How to Use the Popular Science Library; History of Science; General Index

*** START OF THE PROJECT GUTENBERG EBOOK 51133 *** [Illustration: Copyright, Ewing Galloway] [Illustration: _The Majestic, Largest Steamship in the World_] POPULAR SCIENCE LIBRARY EDITOR-IN-CHIEF GARRETT P. SERVISS AUTHORS WILLIAM J. MILLER HIPPOLYTE GRUENER A. RUSSELL BOND D. W. HERING LOOMIS HAVEMEYER ERNEST G. MARTIN ARTHUR SELWYN-BROWN ROBERT CHENAULT GIVLER ERNEST INGERSOLL WILFRED MASON BARTON WILLIAM B. SCOTT ERNEST J. STREUBEL NORMAN TAYLOR DAVID TODD CHARLES FITZHUGH TALMAN ROBIN BEACH ARRANGED IN SIXTEEN VOLUMES WITH A HISTORY OF SCIENCE, GLOSSARIES AND A GENERAL INDEX _ILLUSTRATED_ [Illustration] VOLUME SIXTEEN P. F. COLLIER & SON COMPANY NEW YORK Copyright 1922 BY P. F. COLLIER & SON COMPANY MANUFACTURED IN U. S. A. HOW TO USE THE POPULAR SCIENCE LIBRARY BY GARRETT P. SERVISS HISTORY OF SCIENCE BY ARTHUR SELWYN-BROWN GENERAL INDEX [Illustration] P. F. COLLIER & SON COMPANY NEW YORK PREFACE The final or Index volume of the Popular Science Library not only increases the value of this great set, but actually multiplies it. Volume XVI is in three parts: First, the editor, Garrett Serviss, in "How to Use the Popular Science Library," describes the way the reader may enjoy and profit most from its store of scientific knowledge in connection with his everyday experiences. Then follows Arthur Selwyn-Brown's "History of Science," an excellent foundation for the study of man's achievements in his struggle to understand and turn to his own use the forces of nature. Here is a concise record of progress from the earliest times until now--discoveries and inventions past, present, and about to come. The third part of Volume XVI occupies nearly half the book. It is the General Index, which is as complete and as practical as it is possible for an index to be. Here, then, we have sixteen volumes on science, every work agreeable to read, every work complete in itself, and all of them, including the Index, prepared by specialists, each of whom has already gained distinction in the field he covers. The Index binds the collection into a consistent whole, making every bit of knowledge in the sixteen books available to reader or student without delay. The style employed in the Index is a standard for such material. Volume numbers are represented by the Roman numerals, i, ii, iii, iv, v, vi, vii, viii, ix, x, xi, xii, xiii, xiv, xv, xvi. Pages are indicated by figures. All topics and subtopics are arranged alphabetically. When you read or study the Popular Science Library, keep the Index volume at hand whenever it is convenient. It will add greatly to your interest and give you a depth of insight into these matters if you can compare one author's opinions and descriptions with those of another. If you are consulting the Library as a reference collection for information on particular topics, the Index will give you volume and page for every bit of text on the subject you are considering. The Popular Science Library is unique in the number and standing of its authors and in the care that has been taken to make it the easiest as well as the most engrossing of all scientific collections for the reader or student to use. CONTENTS PAGE HOW TO USE THE POPULAR SCIENCE LIBRARY. BY GARRETT P. SERVISS 9 HISTORY OF SCIENCE 39-198 CHAPTER I. HISTORY OF SCIENCE 39 II. PRIMITIVE MAN AND EARLY CIVILIZATIONS 46 III. PRE-BABYLONIAN SCIENCE 56 IV. EGYPTIAN SCIENCE 64 V. FOUNDING OF SYSTEMATIC SCIENCE IN GREECE 76 VI. GOLDEN AGE OF GREEK SCIENCES 86 VII. THE ROMAN AND MIDDLE AGES 97 VIII. SCIENCE IN THE SEVENTEENTH CENTURY 106 IX. PRELUDE TO MODERN SCIENCE--THE EIGHTEENTH CENTURY 117 X. PHYSICAL SCIENCES IN THE NINETEENTH CENTURY 129 XI. THE NATURAL SCIENCES 139 XII. ORGANIC EVOLUTION, VARIATION, AND HEREDITY 149 XIII. CHEMICAL AND BOTANICAL THEORIES 159 XIV. GEOLOGY, METALLURGY, AND METEOROLOGY 168 XV. MEDICINE AND PHARMACY 178 XVI. ELECTRICITY AND RADIOACTIVITIES 188 XVII. SCIENCE IN THE TWENTIETH CENTURY 195 GENERAL INDEX 199-384 LIST OF ILLUSTRATIONS THE MAJESTIC, LARGEST STEAMSHIP IN THE WORLD _Frontispiece_ FACING PAGE EOHIPPUS--FROM WHICH THE MODERN HORSE DEVELOPED 16 ORNITHOLESTES--A PREHISTORIC ANIMAL OF AMERICA 17 HUNTSMAN, HORSE, AND HUNTING DOG OF LONG AGO--FROM AN ANCIENT CRETAN FRESCO 17 PREHISTORIC PAINTINGS--AN EXHIBITION OF COPIES FROM THE CAVERN AT ALTAMIRA, SPAIN 24 SABER-TOOTHED TIGER THAT ONCE ROAMED OVER NORTH AMERICA 25 GUTENBERG'S PRINTING PRESSES--MODELS ON EXHIBITION 32 BENJAMIN FRANKLIN'S PRINTING PRESS 33 MODEL OF THE "SANTA MARIA," THE FLAGSHIP OF COLUMBUS 48 CURTISS NAVY RACER, THE AIRPLANE THAT WON THE PULITZER RACE OF 1921 49 U. S. ARMY DIRIGIBLE ON A TRANSCONTINENTAL FLIGHT 49 ELECTRIC MOTOR OF 1834 64 TURNING LATHE OF 1843 64 EDISON PHONOGRAPH OF 1878 65 WHITNEY'S COTTON GIN 65 DE WITT CLINTON TRAIN OF 1831 BESIDE A MODERN LOCOMOTIVE 80 LOCOMOTIVE OF THE 1870 PERIOD 81 "JOHN BULL," A LOCOMOTIVE BROUGHT FROM ENGLAND IN 1831 81 WEATHER AND ASTRONOMICAL INSTRUMENTS ON THE ROOF OF GREENWICH OBSERVATORY, ENGLAND 112 MOORING TOWER FOR AIRSHIPS, WITH THE "R-24" FASTENED HEAD ON 113 HOSPITAL ROOM IN WHICH INFECTED ARTICLES ARE STERILIZED 160 MODERN OPERATING ROOM IN PARIS, FITTED WITH A GLASS DOME AND RADIO MICROPHONES FOR OBSERVING STUDENTS AND DOCTORS 161 EDOUARD BELIN AND THE TELAUTOGRAPH, WHICH TRANSMITS PICTURES BY WIRE 176 LEE DE FOREST, INVENTOR OF THE OSCILLATING AUDION 177 AUTOMOBILE WITH RADIO EQUIPMENT FOR LISTENING IN EN TOUR 177 GIFTS FOR TUTANKHAMEN BROUGHT BY ONE OF HIS VICEROYS 192 TUTANKHAMEN'S TOMB--BRINGING UP THE HATHOR COUCH 193 QUEEN NEFERTITI, MOTHER-IN-LAW OF TUTANKHAMEN AND WIFE OF AHKNATON 193 HOW TO USE THE POPULAR SCIENCE LIBRARY This series of books is written for all the people and not for specialists only, though it is the work of specialists who know how to explain their subjects clearly and interestingly, without unnecessary technicalities and with keen appreciation of the popular and constantly increasing desire for scientific knowledge. The supreme importance of science in the wonderful age in which our lot has been cast was demonstrated with overwhelming force of conviction by the events of the World War. If, as certain persons assert, science may be accused of having rendered war more destructive and terrible, yet, on the other hand, no one can deny that it was science that saved the world from sliding backward into an age of despotism. The true importance of science for everybody arises from its rapidly increasing service in the development of human industry in all its forms, for industry is the mother of democracy. Said Gabriel Lippman, the French physicist, inventor of color photography, who died in the summer of 1921: "For thousands of years science progressed by groping and feeling its way, and coincidentally industry got slowly on by guesswork; but within the last century science has developed more than during all preceding time, while industry has sprung upon its feet and begun to march with the strides of a giant." Notwithstanding its immense importance and the vast extent and complication of its application in modern times, science is not really difficult for any person of ordinary school education and of good natural intelligence to comprehend, provided it is presented in a clear, plain, common sense manner, in popular language with illustrations drawn from everyday life and experience. The much talked-of methods of science are, after all, nothing more than the methods of common sense, applied with systematic care by minds disciplined to a high degree of efficiency. And, in fact, the only practical difference between the mind of a trained scientist and that of any other intelligent person is that the scientist has acquired a way or habit of looking at and thinking about things and events, which enables him to get at their inmost nature and meaning more swiftly and accurately than he could do if he went to work in a haphazard manner as, in truth, his forerunners of the earlier centuries were obliged to do. The pioneer must always work by rule of thumb, but when he has exploited his field he knows better ways. Each branch of science has its own particular methods, but it is not necessary for the average reader to study these special methods in order to become able to grasp the facts and principles that have been developed by them. The results are all thrown into a common store--or should be if science is to attain its utmost usefulness to humanity--and from the common store the great public, the people at large, should be enabled freely to draw. The object of this series of books is to form such a store of science for the people. It may encourage those who look with some degree of timidity upon the task of trying to understand the great discoveries and achievements of modern science to know that even the ablest scientists, leaders in their own particular branches, do not pretend, or attempt, to grasp the special methods or the technicalities of any division of science except that one in which their own work is done. They stand, with regard to other branches, practically on the same footing with the unscientific reader, having over him only such possible advantages as their special training in clear thinking and in the intense application of the mental powers may give them. Besides, science is really the most interesting thing in the world--outside of men and women--and _they_ would be less interesting, even to themselves, if science had not transformed their lives as well as their surroundings. If one of Voltaire's favorite messengers from some other, wiser world had visited our earth a few hundred years ago, or even only one hundred, and should now repeat his call, he would be amazed, and no doubt delighted, by the changes in every feature of life and society which he would find that science had brought about, as if by magic, during the interval between his visits. He would be likely to exclaim: "Some great teacher and trainer from a more enlightened part of the universe must have been here since I saw this world before. What a marvelous new spirit he has imparted to these creatures. Through him they have become more masterful and more like sons of God." See if you can find a single detail of your daily life that is not affected by science, or upon which science does not throw new light. It is fascinating to trace out the scientific relations of the simplest things that surround us, or the most ordinary occurrences and incidents. Start with your first awakening in the morning, and you will perceive that there is not a thing that you see, or that in any way attracts your attention, that is not touched and illuminated by science, and often in the most unexpected and delightful ways. It is by considering these things that one may best perceive how to use the volumes of this little library. As you open your eyes in the morning you see a bright glow through the window curtain, then you know that the sun has risen. But stop a moment. What does that mean--"the sun has risen"? The sun has not "risen" at all. But, one of the greatest facts of the science of astronomy is illustrated before your eyes--a fact that it took mankind thousands of years to find out. You are standing in the astronomer's shoes now, if you choose to wear them. This is a part of his field of science. It took him a long time to convince the world that the "rising" of the sun in the east next morning after its "setting" in the west really means that the globular earth has turned half way over during the night. If this seems simple to you now, it seemed very hard to comprehend to our remote ancestors, who, though reasoning men like ourselves, had not learned as much about the relativity of motion as we now know, though even we may be puzzled by some of the consequences that Einstein has drawn from it. And a hundred other things that astronomy has discovered about the sun and the other suns, called stars, and the other worlds, called planets, immediately rush to your mind, and you turn to the volume on astronomy to read about them. But this is only a beginning of the string of everyday incidents that are rendered curiously interesting as soon as their scientific relations and meanings become evident to you. Science is right at your elbow to raise questions and to answer them the moment you step out of bed, and your mind begins to work. As you throw open the window to see what kind of a day it is going to be, whether fair, or cloudy, or rainy, cool or warm, you draw your conclusions from the appearance of sky and air, but in doing that you are entering another field covered by another branch of science and included in our little library--meteorology, or the realm of the air--and you may be sure that the correctness of the conclusions that you draw from the aspect of the clouds and the feeling of the air will be greatly increased, not only in certainty, but also in interest, if you read what the students of this subject have learned about the laws and the mysteries of the rains, clouds, cyclones, barometric pressures, great winds and genial breezes, great storms and little storms; in short, the whole wonderful science of the atmosphere, that invisible, yet powerful kingdom of the air, which we are just beginning to annex to our world of activities without regard to what its natural occupants, the birds, think of such an invasion. Now you leave the window to begin making your morning ablutions. You turn on a faucet and take a drink, or plunge hands and face into the refreshing liquid, so cool, lively, and invigorating. But a bird or any four-footed animal may find just as keen physical enjoyment in the touch and taste of the water as you do. You, however, because you are a thinking being, possess a source of enjoyment from the touch and appearance of the water that is not open to those humbler creatures, and that source of enjoyment springs from the principles and facts of another branch of science which the mere sight of the running water may call to mind if you have caught the spirit of these books--the science of chemistry, whose early history is filled with that irresistible kind of romance that pertains to the search for Eldorado, or the strivings of the human spirit after the powers of magic; for the realm of chemistry was once a kind of semi-scientific dreamland, wherein the "alchemists" delved at the same time for the "philosopher's stone" which was to turn base metal into gold, and for the wand of the magician which would give to its possessor the boundless gratifications of a Faust. Water is no mystery to the lower animals, but it is a great mystery even yet to the highest ones--ourselves--because we have been enabled to analyze it. You cannot look at it pouring from the faucet, and sparkling into bubbles, without recalling the fact that it is composed of two invisible, silent gases, and that chemistry tells us not only how to make the water disappear by taking those gases apart, but also how to form new water by making the two gases combine. The mystery is--why should this be so? It is a captivating question, and the business of the book on chemistry is to give you all possible light on the solution of that question, and others of a like nature. You will find, too, that the very latest chemistry has, strangely enough, discovered a sort of justification for the extravagant expectations of the ancient alchemists, by finding a way in which one substance may actually change, or be changed, into another, different substance--one "element" taking the form of another "element"--and also by getting clues to the existence of marvelous locked-up energies in matter, the release of which would give man control over powers that could properly be called "magical." After finishing your toilet, with all the suggestions and remembrances of chemical science that it has produced, you start to quicken the circulation of your blood by catching up a pair of dumb-bells, or Indian clubs, or by pulling elastic cords, or banging a leather ball with your fists, as if you meant to go in for the championship of the world. Now, what taught you the value of such exercises? You are still on the ground of science, and you are practically demonstrating the principles of another of its branches--the science of health, or hygiene, which is a part of the subject of medicine, taken in its broadest signification, for, as the volume on that subject will assure you, the greatest service that this science can render to mankind is in teaching us the laws of our physical existence, and indicating, directly or indirectly, how all the functions of the body may be kept in the best working order by proper attention and exercise. You will find such things pointed out in the several sciences that deal with the body, such as physiology and medicine. While you are making the leather ball strike the ceiling with resounding whacks, your dog, excited by the inspiring noise, bursts into the room, and interrupts your exercise with his enthusiastic morning greetings, expressed as energetically by his wagging tail as by his joyous barks and licks, all anticipatory of a lively morning run. He brings immediately into your mind the thought of still another division of science--zoölogy--to which you will devote many pleasant half-hours of reading, for it is full of most entertaining matter, as well as of matter calculated to awaken profound and useful thought concerning the relations of the many different members of the animal world to one another, and especially to their head and chief, man, to whom the supervision of the whole was, according to the Bible story, originally committed. Familiar as your dog may be to you, there are a hundred particulars of his family relationships, his descent from wild ancestors, etc., which can only become known to you through the studies that have been devoted to the science of zoölogy by curious-minded investigators from the times of Aristotle and Pliny down to our own day, when we have seen an ex-President of the United States wandering adventurously through some of the remotest portions of the inhabited globe, seeking fresh knowledge of, and personal acquaintance with, the rarer kinds of wild animals, and hunting down in their native wilds great beasts which the Cæsars used to admire from the security of the imperial seat, high above the bloody sands of the Roman arenas. And this modern ruler, after having laid down the political power intrusted to him by fellow citizens, found no occupation so attractive as that of adding something to the growing stores of science. [Illustration: Painting, Chas. R. Knight. (American Museum of Natural History) THE LITTLE EOHIPPUS. FROM WHICH THE MODERN HORSE DEVELOPED] [Illustration: ORNITHOLESTES--PREHISTORIC ANIMAL OF AMERICA] [Illustration: Photo, Metropolitan Museum HUNTSMAN. HORSE AND HUNTING DOG OF LONG AGO From an ancient Cretan fresco] Next, your stomach, awakened to its wants and needs by the restored circulation resulting from your lively exercises, reminds you of what will be at the same time a pleasure and a means of sustained strength for body and mind, your breakfast. Breakfast properly comes under the supervision of the science of physiology. It is also suggestive of mechanics and physics, since it has to do with the stoking of the furnace that keeps the bodily engine up to its work. Here you are face to face with a branch of science which you could no more safely neglect than an engineer or a fireman could neglect to learn the elements and principles underlying his critically important occupation. One of the first sciences to be systematically developed was that of man's body, including its structure, or anatomy, and its functioning, or internal action, physiology. You will find that correct ideas on these subjects were slow in being developed, yet even in the most ancient times men were shrewd and wise enough to understand the importance of knowing something about their own bodies, in order to be able to take proper care of them, and to deal with wounds and sickness. It was an old saying that "the proper study of mankind is man." But that is a study which has two main branches. The first covers the subjects of physiology, anatomy, medicine, etc., while the second relates to that even more intimate part of ourselves which has ever been a fascinating mystery, and which we call the mind, or sometimes the soul. This is the theme of the science of psychology, whose name comes from that delicate, inscrutable spirit, _Psyche_, the Soul, which plays like a flitting sunbeam through the magical atmosphere of Greek mythology. Now, this subtle and exquisite science, often more poetic and mystic than scientific in its original character, presents itself in its more sober and practical dress to you as soon as, having finished your breakfast and prepared your bodily energies for the day's work, you begin to meditate on the problems of the day opening before you. When you went to bed, perhaps your mind was agitated by some important matter of business through whose intricacies you could not clearly see your way. You turned and tossed on your pillow, and stated and restated the facts and arguments and lines of reasoning, but all the while they became more obscure and entangled until at last, in sheer exhaustion, you fell into a troubled sleep. But this morning, to your immense surprise and gratification, without any effort on your part, and while you are occupied with other things--putting on your clothes, hitting the ball, playing with the dog, eating your bacon and eggs, or what not--suddenly the elusive clue or solution, so vainly sought the night before, presents itself plain before you. In an instant, in the twinkling of an eye, the troublesome problem is solved, as easily and naturally as water runs down hill, and you are provoked at yourself for having been so dull and stupid as not to see it all before. But not so fast! You were stupid, to be sure, but it was not your mind's fault as you are now disposed to think, but the trouble lay in your physical fatigue. You were driving your brain too long without refreshment, and it became like an engine whose oil cups are empty. It could not receive and report the impressions of thought. Now this kind of experience comes many times to many men and women, and it is the purpose of the book on psychology in this series to make everybody acquainted with the laws of the working of our minds through our brains. Yet, how many of those who are frequently puzzled by such things are aware that there is a branch of science, one of the most captivatingly interesting of all, devoted especially to this subject? By studying the volume on psychology you will get light on just such things as so greatly puzzled you, and haunted you, before the solution of your problem unexpectedly rose up, as it were, and stood plain before you on the breakfast table, after having for twenty-four hours resisted your utmost efforts to master it, or even to get an effective hold upon it. It is unnecessary to speak of the immense importance to all human beings of a knowledge of the laws governing the manifestations of the mind, by taking advantage of which they may get the most out of themselves with the least loss of time and expenditure of effort. Let us keep on further along the wonderful road of science on which your feet begin almost unknowingly to tread from the moment of your awakening, and which they follow, often just as unconsciously, until you fall asleep at the close of another day; while, as we have just seen, even when we are asleep our minds are not altogether inactive, and may even secretly disentangle the puzzles of the day while our tired brains are restoring themselves with slumber. Perhaps you live in the suburbs of a city, or far from the business center, and have to take a considerable journey from your house to your place of work or business. Maybe you go by automobile, or by street car, or by a trolley route, or take a commuters' train. In any event, whether you drive your own car, or ride in one drawn by a motor or a locomotive engine, you are brought face to face with the science of physics, including, of course, not only mechanics, but also, in our own day, electricity and magnetism. If you glance at a steam locomotive, puffing and blowing, and then at a smooth, silent electric motor drawing a long train, and then at a swift automobile winding and turning with serpentine agility through crowds of slow horse-drawn vehicles--in all cases your memory must recall the long, hard road by which these things were brought about, and you must be lacking in intelligent curiosity if you do not resolve to know for yourself, not only the history of these triumphs of human invention, but the principles of action upon which they depend. If you have a car, it would be a good thing to drive it yourself and learn to take care of its machinery yourself, for thus you would go far toward mastering the elementary principles of the science of mechanics, which has done more than all other things combined to transform the face of the world we live in. You cannot, of course, acquire all this knowledge by practical experience, but by putting together what you observe with what you read in the volumes devoted to mechanics, physics, chemistry, electricity, etc., you will find that every day is a school day for you in which you have learned something new, useful, and interesting, and something, moreover, which every wide-awake person in this wide-awake age ought necessarily to know, and can know by pursuing such a course as that just suggested. Your morning's ride to work will be transformed into a delightful intellectual experience if you prepare yourself by a little daily reading to understand the construction and manner of working of all the machines, engines, and mechanisms presented on every side to your inspection. But machinery is not everything in life. Suppose that as you ride along your eye is caught by the great beauty of the flower gardens by the roadside, their blossoms bright in the morning sunshine and sparkling with the yet undried dew, as if sprinkled with diamonds. Perhaps your attention may never before have happened to be called so strongly to these objects, and possibly you have hitherto remained almost unacquainted with the names and peculiarities of some of the most common plants and flowers. But this morning, for some accidental reason, which may have a psychological origin, you are particularly charmed with the brilliant sight, and you resolve that you will be no longer ignorant of what could, manifestly, give you so much pleasure, besides being of unquestionable usefulness. When you return home you will take up the volume on botany, and it may lead you into a realm of mental delight previously unknown to you. If it is the springtime, you may be interested by the sight of a tall, graceful tree, as lofty as a pine, and as straight in trunk, with many exquisite blossoms hanging from the pendulous stems on its great limbs, fifty or more feet above the ground, as if it were a flower garden in the air for the special delectation of the birds. Having never heard of a flowering tree outside the tropics, you feel a keen desire to know what this one is, and thus a way of introduction, founded on keen, personal interest, is opened for you to the science of botany. And few persons can take a ride, or a walk, anywhere in city or country or park, without having attention attracted by some unknown flower or plant, or tree, and without becoming aware how much pleasure is lost, and how much useful knowledge missed, by lack of the easily acquired knowledge of these things, which anybody can have by giving to it only that amount of time which would otherwise be wasted almost as completely as if the eyes were kept closed and the mind dismissed from its home in the brain. More mysterious, and not less fascinating than flowers and trees, are the birds and insects that flit by on their own errands. To explain them you have the volume on zoölogy, the science of animal life. Botany and zoölogy together go far to revolutionize the ordinary man's ideas about the attractiveness of outdoor life. For the cultivator of the soil, whether farmer, gardener, or fruit grower, botany, of course, is the queen of sciences--though he may not safely remain ignorant of the others mentioned, which form a brilliant court for his queen. In no direction has science lately proved itself so indispensable as in the application of botanical knowledge to the improvement of agricultural operations of all kinds. In France, always one of the richest of lands in this respect, the government has since the war made special provisions for placing instruction in botany and plant physiology, and the results of all advances in the science of the vegetable kingdom, before the pupils of the primary as well as those of the secondary and higher schools. Botanical reading and study are encouraged in every possible way. One of the most significant propositions for the extension of this educational reform consists in the suggestion that the schools in the country districts give much more attention to the various branches of botanical knowledge than the city schools do, for the purpose not only of supplying instruction that will be of fundamental practical use to the young people who grow up on the land and are to make its cultivation their life's occupation, but also of stimulating a love of the country for itself, its scenes, its atmosphere, its society, its amusements, and its simple, beautiful, and healthful ways of life. As your train, or car, rushes through a rock cut where the roadway has been carried, without change of level or grade, through the round back of a hill, you may happen to see on the side walls of the excavation curious striations, or cross checkings, of the rock surface, or alternate strata, or layers, of varying color and texture; some composed of smooth-faced stone, of a dark, uniform color, and others of coarse granular masses of variegated hue, some of whose particles flash like microscopic mirrors in the glancing sunlight that grazes the top of the cut. Here, then, you are plunged into the wonder world of the geologist and the mineralogist, the subject of one of the most interesting of our volumes. That man must indeed be dull of intellect who does not feel a thrill of interest at the sight of these signs and inscriptions, written by the ancient hand of nature in the rocks, and telling, in language far more easily decipherable than the hieroglyphics of Egypt, the story of the gradual growth of this round planet on whose surface we are confined, like flies or ants, as it rotates and revolves in empty space, circling with us around a star, ninety-three million miles away, called the sun, which saw the birth of our world and has ever since kept it warmed and lighted with its rays. In those layers of rock in the railway cut you see the leaves of the book of geology, infinitely older than the oldest scripture from man's hands, and relating things that occurred in those far-off nights and mornings of time that flitted over the globe ages before the human stem had set off from the trunk of terrestrial life. These geologic pages speak of occurrences in the building of the world that happened millions of years ago, and millions of years apart, though they have left marks and vestiges that the eye can discern as easily as if they had been the work of yesterday. No observant person can ride twenty miles through the country, especially in a hilly region, without having the fundamental facts of geology continually before him, and all that he needs in order to comprehend these things is a little preparatory reading, accompanied and followed by intelligent thought and observation. Anybody to whom all rocks look alike, and all hills the same, needs a little awakening of the mind. He is one of the persons had in view when this series was conceived and written, and he has no occasion to feel in the slightest degree offended by such a statement, for the simple fact that probably ninety-nine one-hundredths of his fellow citizens, and they among the best in the community, are just as unfamiliar with the plainest facts of geology as he is. Geology is not a difficult science to master in its main outlines, and there are few more fascinating when once its drift is caught. Even the beginner in the reading of the volume on geology, by seizing such chances of observation as every ride or walk affords, may in a very short time acquire the ability to read the history of a landscape from its face, to recognize the work of the glaciers in the great Age of Ice, to see where ancient streams flowed, or where molten rock has gushed up through the surface layers of the earth's crust, and even to recognize on sight some of the fossils, which are under everybody's feet in some parts of the country, and which still retain the forms of animals some of which were among the primal inhabitants of the earth, whose lines have died out, while others, though their individual lives expired tens or hundreds of millions of years ago, bear in their fossilized forms a close resemblance to modern relatives and descendants whose generations still flourish in the living world in this twentieth century of man's latest historic era. Presently, turning from the attractions of the outdoor world, which seem just as entrancing the hundredth time you look upon them as they did the first time, particularly if you have cultivated the habit not merely of noticing but of thinking and reading about them, you take up the morning newspaper, in which most of your companions of the car are already deeply buried, and amid the political news, the personal gossip, the inevitable exploitation of the deeds of criminals, the foreign intelligence, and the social gossip that falls under your eyes, your attention is caught (this is an actual happening of not long ago) by the headline: "John Daniel, the orang-utan, is dead." This sounds odd. There has been no animal's obituary in the papers since Barnum lost his biggest elephant, and bequeathed its skeleton to science. You read further and find an interview with a professor about the human relationships, or apparent relationships, of the anthropoid apes, of whom "John Daniel" would probably have been the acknowledged king if his relatives of the woods could have understood the regard in which he was held by his white-skinned and clothes-wearing jailers. You will probably cut out that paragraph and put it aside for further consideration, remembering that there are at least three volumes in your Popular Science set at home, that on zoölogy, that on geology, and that on anthropology, in which there will be an abundance of interesting and authoritative matter bearing on this most important subject--for important you will consider it now that the death of a kind of caricature of humanity in the zoölogical garden that had so long amused the children as well as their elders with its humanlike motions, habits, looks, and pranks, has suddenly brought the whole question up among the news of the day, affording you a new light on a matter which you had hitherto thought to belong exclusively to the field of the professors of zoölogy and their students. Hereafter you will disposed to take a broader view of all these things, and will be in a better position to understand and enjoy the discussions of learned scientists when they are interviewed by newspaper men on subjects of this kind. The inquiring spirit of the time requires this concession even if in your private opinion there is no real relationship between men and apes. And, without regard to any such questions, you will find the volume on anthropology immensely interesting and informing. Finally, as your morning's trip comes to an end, your attention is recalled from the natural to the mechanical sciences. You descend from your car or train, to go to your office. Your now fully awakened mind, alert to all the scientific relations of everything about you, can no longer keep from dwelling upon the underlying meanings of this marvelous display of realized human dreams. With the speed of the wind you are carried deep under the city's pavements, inclosed in a little flying parlor, in the midst of an artificial subterranean daylight, far beyond the reach of the solar rays, emulating the self-luminous creatures of the deep sea bottom; or you go shooting past the window of third, fourth, and fifth stories, or even above the levels of roofs, and you cannot but reflect and marvel that electricity does it all; electricity, that strange imp with blue star eyes no bigger than pin points, and a child's crown of little crinkling, piercing rays, which seemed so amusing when you were at school in the old days of frictional electric machines, when it was a great joke to give the cat a shock and see her flee with a squall, her hair standing on end in spite of herself. But now electricity has become a giant of unrivaled and terrific power, spurning the heavy-limbed Brobdingnag, steam, from its swift path, and fast making the world all its own--except its master, man, who is still, however, half afraid of his new and all-capable servant. [Illustration: EXHIBITION OF COPIES OF PREHISTORIC PAINTINGS FROM THE CAVERNS AT ALTAMIRA, SPAIN] [Illustration: Painting by Chas. R. Knight. Photo, American Museum of Natural History THE SABER-TOOTHED TIGER THAT ROAMED OVER NORTH AMERICA IN PREHISTORIC TIMES] This modern genie of limitless power, conjured out of his deceptive bottle, can do the smallest as well as the greatest things for you. When, upon reaching your office, you telephone to your wife that Mr. Blank will be home to dinner with you, you cannot form the slightest idea of how the miracle of distant speech is accomplished unless you are either an electrician yourself, or have read intelligently upon the subject of the applications of electricity to the motivation of all kinds of machinery, a subject to which an entire volume is devoted in our series. It would be a kind of shame and reproach to an intelligent man to be ignorant of the way his telephone works, and of the simple scientific principle on which it is constructed. If telephones, and such things, were products of nature and grew on trees, we might be excusable for not knowing exactly their secret; but being made by men, with the same limitations as those that circumscribe us all, we ought at least to understand them. Thus, by a simple review of the series of common happenings that arrive every day to everybody, we perceive how intimately and indissolubly the various branches of science treated of in this compact library of science, are linked with all that we do, including our most unconscious acts and our most habitual subjects of thought. We have taken for illustration the morning history of a person supposed to live amid urban or suburban surroundings. Equally illuminating would be that of an inhabitant of a village or a rural district, and even more suggestive in many respects. The dweller in the country is brought into closer association with the infinitely changing aspects of nature than the city dweller enjoys. The simplest incident in the life of a person living on a farm may be the beginning of a thread of connection leading, like the clue of a labyrinth, into the heart of some of the most marvelous departments of science, and resulting in a mental revolution for the fortunate person who follows out the clue under such guidance as these volumes afford. The writer has remembered from boyhood the indelible impression made upon his mind by the finding of an Indian arrowhead in a recently ploughed field. The shapeliness of the beautifully chipped piece of flint, almost as translucent at the edges as horn, the delicate tapering point which, as if by miracle, had remained unbroken probably since colonial times, the two curious little "ears" carefully formed on each side of the flat triangular base to facilitate attachment to the head of the arrow, and the thought, suggested by older persons, that this weapon might actually have been used in some midnight attack on a white settlement, made more terrifying by the frightful Mohawk war whoop and the display of the reeking scalps of human victims in the glare of burning stockade and cabins--all these things bred a keen desire to learn the particulars of the history of the red warriors of the Five Nations, the "Romans of the New World," and also to know something about the life and customs of this strange, savage race of mankind which continued to live in an "age of stone" on a continent that had never known civilization. No volume like that on the history and development of man in this series existed at that time; but if such a book had existed and had fallen into the hands of the finder of the arrowhead, it would surely have fascinated him more than "Robinson Crusoe" did, because a boy can distinguish as readily as a grown person the superior interest of the true over the pretended, provided that the true possesses the real elements of romance. So, too, the writer remembers having an interest in mineralogy awakened in his mind, never to be obliterated, by the sight of another plowed field, in the southern skirts of the Adirondack Mountains, whose freshly turned furrows glittered in the sunshine with thickly scattered quartz crystals, some of the larger and more perfect of which blazed across, the whole breadth of the field, like huge diamonds, and made the heart of the finder beat with an excitement akin to that of the discoverer of a Koh-i-noor. There were also some very curious "stone buttons" which one could break out with a hammer from slate rocks along the Schoharie Creek, and which, when cracked open, were found to be composed of pyrites that resembled pure silver--and sometimes gold--freshly broken. Now, things of this sort are always attracting the attention and awakening the curiosity of children living in the country, but the real pleasure and instruction that they might afford are usually missed because of the lack in the family library of popularly written books on the natural sciences--a lack that we are trying to supply. For city children and their elders, whose eyes are constantly greeted, not by hills, creeks, ponds, rivers, woods, and fields, but by sky-aspiring buildings, railroads elevated on stilts, multiple-decked suspension bridges, electric power houses, tunnels that form a second city underground, and the thousand marvels and splendors of electric illumination at night, the volumes on physics, mechanics, and electricity and magnetism have a more immediate interest and value. What the children learn about these things in school is far from sufficient to satisfy their curiosity. They need books at home to guide their inquiries as well as to answer them. Only by that means can the diffusion of scientific knowledge, and the popularization of the scientific method of getting at the truth and the meaning of things be thoroughly effected. Science, as its history plainly demonstrates, progresses most rapidly only when a great number of minds have been led to concentrate their powers upon its problems. Great genius, it is true, rides over obstacles; yet consider how much further its energies might have carried it if the obstacles had been more or less completely removed in advance. Many a young man has been led to a brilliant career, to the great advantage of his country and his time, as a result of the interest awakened in him by the clear statements of a popularly written book on some branch of science. One of the difficulties that persons unfamiliar with certain branches of science encounter in reading about them arises from the excessive use of technical terms, the lack of simple illustrative examples, and also, sometimes, a lack of sympathetic appreciation of the reader's difficulties. It has been a special object of this series to avoid this trouble. Ordinary textbooks are prepared for students in school and are intended to be supplemented by the personal instruction and guidance of a teacher, standing at the pupil's elbow, or readily approachable. But the reader who wishes to inform himself upon some progressive branch of science after his school days are over needs to have the teacher included in the book itself. Then, too, there are many persons who have no comprehension of the great and gratifying power that a knowledge of some of the elementary principles and formulas of science bestows upon anybody who may take the little trouble necessary to master them, a trouble that does not imply a long course of scientific study. The "man in the street," if he possesses these easy-working keys to knowledge, can verify for himself some of the calculations of scientists which, if he did not know how they were done, would always remain for him in the category of the mysterious achievements of genius. To illustrate, let us take a simple example--that of the Newtonian law of falling bodies. Many persons would assume on the face of it that there was nothing in this law that could have a particular interest for them. But let us see. You will find in the volume on physics that the law is stated thus: S = ½gt², i. e., "S equals one-half of the product of g multiplied by t squared." As you look at it you would, perhaps, as soon think of picking up a complicated tool and trying to use it for some ordinary purpose. Nevertheless, let us try. "S" in the formula means the space or distance traversed by the falling body, "g" means the velocity that the force of gravity imparts in each successive second to the body, and "t" means the time elapsed during the fall. What the formula tells us, then, is that if we observe the time during which the body is falling, and then square the number of seconds involved (multiply the number by itself), multiply this square by "g," which is represented practically everywhere on the face of the earth by the number 32, and finally divide the whole by 2, we shall have the distance that the body fell. This distance will be in feet, since the number 32, representing "g," is in feet. Now, it might be a matter of life and death, or at any rate of mental discomfort against quietude of mind, to have that rule in memory and to be able to apply it. For instance, you are on your vacation and stopping in a strange hotel, where they have put you in the top story. On looking out of the window you are dismayed at finding no fire escape, or other appliance of safety, so that your only resource in case of fire would be to make a rope out of the bedclothes and let yourself down with it. But, how far is it to the ground? How long should the rope be? Are there sheets enough on your bed to furnish it? The little formula about falling bodies will answer the question for you in five minutes. First, you let some small solid object drop from the window, and note by your watch, or by counting seconds, which everybody ought to teach himself to do, how long it takes to reach the ground. You repeat the experiment two or three times to make sure. Say the time comes out three seconds. Very well, now apply the rule: The square of 3 is 9, and 9 multiplied by 32 gives 288, and dividing by 2 you have 144 feet for the height! It is to be feared that your bedclothes rope would not be long enough; you had better send to the office for something to supplement it. But if the time of fall should be only 2 seconds, which is more likely, except in skyscraper hotels, then the calculation would give you 64 feet for the height, which you might manage with the aid of the bedclothes. [Illustration: MODELS OF GUTENBERG'S PRINTING PRESSES The models show three stages of development, the first of them at the right] [Illustration: BENJAMIN FRANKLIN'S PRINTING PRESS The original is now in the National Museum at Washington] This is only a single example among many that could be given to show the usefulness and interest of many of the formulas of science which the ordinary reader looks upon as beyond the reach of any person whose occupation leads him another way. But cases of equal simplicity could be found in connection with the subjects of electricity and magnetism, chemistry, medicine, physiology, etc. Sometimes it happens that a technical word contains its own definition and explanation in a nutshell. A striking instance of this will be found in astronomy, in the word "light-year." The meaning of this word stands forth on its face--it evidently expresses the distance that light travels in the course of one year. Now, since it is known by means of direct measurement that light goes at the rate of 186,300 miles per second, manifestly a light-year must be equivalent to an enormous number of miles. In fact that number, roundly stated, is no less than 5,860,000,000,000. But to what marvelous regions of thought such a term opens the way! Yonder star is 2,000 light-years distant from the earth; then its light-waves now entering your eyes left it when Julius Cæsar was conquering Gaul, and have been speeding on their way to the earth ever since! Another star is found to be 5,000 light-years distant; then the light by which you now see it started from the star when Abraham set out from Ur of the Chaldees to settle in the Holy Land, and has not found a resting place anywhere in boundless space until just now when its tiny waves break and expire on the retina of your eye! Such treasures of knowledge and tonics to thought are scattered all through the volumes of this set, the purpose of whose publishers, editors, and writers has been to accumulate such things in small compass and in crystal clearness, for the use not only of those who, after their school days are over, still wish to keep abreast of the progress of science in all its branches--as everyone should strive to do in this most scientific of all ages--but also for those who have hitherto not had the time, or the opportunity, or perhaps even the desire, to make themselves at home in the house of science. It may be well to add a few words on the interrelation of the different subjects treated in the various volumes of the series. This will suggest to the reader himself the best order in which to take up the reading of the books. Naturally he will desire to obtain both a clear general view of the whole field of science, and also more detailed acquaintance with its special parts, the amount of detail depending upon his particular interest in a subject. For the first purpose the preferable way would be to run first over the brief account that follows in this volume, of the history and development of science in general, and then to take up the simpler and more easily grasped branches. But it should be firmly kept in mind that, fundamentally, science is one, having in all its branches but one aim and object, viz., the ascertainment and demonstration of the exact truth of things as far as human capacities are able to reveal and comprehend such truth, and also but one method of procedure, which is the method of common sense trained to the utmost attainable exactitude in observation and the greatest possible clearness and precision of reasoning. Science properly so-called confines itself to things that are subject to observation by the senses and to verification by repeated observation and experiment, while its reasonings and predictions are based entirely upon the unvarying sequence of the phenomena of nature, as they display themselves before us. Science is just as one and inseparable as life, or as an organic being, and its divisions no more imply lack of unity than do the various organs and limbs of an animal, or a tree, or the different structural parts of a building. Astronomy is not entirely independent of geology, nor geology of botany, nor botany of chemistry, nor any of these of physics, nor physics of electricity and magnetism, nor the last of physiology and medicine. Accordingly the question where to begin in studying science is not one that can be answered in the same way for everybody. But the spirit is the same in all the branches. Perhaps the best general indication of the order in which a person who has no predilection for any one branch of science should take up the various parts is afforded by their historic development. This was a result of the natural reaction of man's mind to its surroundings. The things nearest to him, and most immediately important, first attracted his attention. The broadest division would be into the science of things on the earth's surface; the science of things above the earth, in the air and the sky; and the science of things within the earth, concealed from immediate view. If we take these in their order they naturally subdivide themselves as follows: 1--THINGS ON THE EARTH--EXPLAINED BY (a) Anthropology, the Science of Man and His Ancestors, treating of his nature, origin, development, division into races and tribes, society, industry, etc. (b) Zoölogy, the Science of Animal Life, treating of the "lower animals," and of animal life in general as distinguished from the kingdom of the plants, although the related science of biology deals with both plants and animals, its special subject being the phenomena of life in its widest sense. (c) Botany, the Science of Plant Life. (d) Geography, combined with Physiography, the Science of the Face, or Superficies, of the Earth, dealing with lands and seas, rivers and mountains, political divisions, etc. This is covered in our series by the volume on Physiography. (e) In this compartment several branches of science may be grouped, since they are all the product of study of things encountered on the earth's surface. They are: _Physics_, the Science of the Forces of Nature, dealing with the laws of the inanimate world around us, including the phenomena relating to solid, liquid, and gaseous bodies and substances. _Chemistry_, the Science of Matter and Its Changes, dealing with the atoms and their constituents, and with the combinations of atoms into molecules to form the various chemical elements, etc. _Electricity_ and _Magnetism_, the Science of Power, fundamentally underlying all other branches, and through its investigation of the nature of the constituents of atoms--the electrons--going deeper into the constitution of things than chemistry itself. In fact this science, in some respects, blends with chemistry, although it is quite separate when it deals with the mechanical developments of electromagnetism. _Medicine_, the Science of Health, _Physiology_, the Science of the Body, _Psychology_, the Science of Human Behavior, _Mechanics_, the Science of Machinery, etc., also naturally fall into this category of Things on the Earth. 2--THINGS ABOVE THE EARTH--EXPLAINED BY (a) Astronomy, the Science of the Heavenly Bodies. (b) Meteorology, the Science of the Atmosphere, rains, winds, storms, fair and foul weather, the changes of the seasons, and essentially related to the new and fast developing art of aerial navigation. 3--THINGS WITHIN THE EARTH--EXPLAINED BY (a) Geology, the Science of the Earth's Crust, or shell; which also deals with the various stratifications of the rocks, superposed one above another, and containing in the shape of fossils, and other marks, a wonderful record of the character and development of the living forms that have inhabited the earth during the long ages of the past. Of course some of the phenomena dealt with by geology are manifest on the earth's surface, and others, like volcanoes and earthquakes, hot springs and geysers, are partly subterranean and concealed from sight and partly evident by their effects on the surface. (b) Closely associated with Geology are Mineralogy, the Science of the Constitution and Structure of Rocks and of Mineral and Metallic substances; Vulcanology, the Science of Volcanoes, and of earth disturbances in general; and the Science of Mining, which has several branches, and forms the basis of enormous industrial developments. It is manifest, as before said, that the reader must be his own best judge as to the precise order in which to take up the perusal of the volumes in which this immense mass of scientific knowledge is presented. But, where there is no predisposition to choose one subject rather than another, or where there is a desire to follow, as nearly as may be, the natural line of development of human knowledge, it would be well to take first, after the history, the volume on astronomy, a science that from the beginning has had a peculiar power to awaken intellectual curiosity; then that on anthropology; then the various so-called "natural history" subjects, leaving the mechanical and the more technical subjects for the last. Or, the reader might first take up the subjects of personal importance to every human being--Medicine, the Science of Health; Physiology, the Science of the Human Body; Psychology, the Science of the Mind--every one of which is essential to the proper care and preservation of life; and afterward study the other branches in the order already suggested. [Illustration: ~Garrett P. Serviss~] CHAPTER I HISTORY OF SCIENCE The romantic history of science shows how the discoveries of the greatest human minds, slowly operating since the remotest times, have made possible our present-day civilization. Few studies are worthy of greater attention; no other department of knowledge affords more real pleasure. Whoever clearly understands the history of science possesses intellectual advantages over those who are ignorant of the causes that have led to the establishment of the basic principles of our modern industrial arts and applied sciences. Standards of comparison are furnished by the history of science which illuminate many of the wonders of to-day, develop alertness of mind, and afford a never-ending train of suggestions for thought. The term science means knowledge. It was derived from the language of the Romans. It is well to have a clear idea of the meaning of the word. Everyone knows that it has to do with certain kinds of knowledge; few know the particular kinds it embraces. It does not mean the mere knowledge of a single fact. It does not mean a knowledge of something which has to be done. Long before science was born, our early ancestors observed many isolated physical, philosophical, and religious facts. They knew that day followed night, that the stars moved, that every day the sun progressed over the arch of the heavens. Such facts did not constitute science. What we know as science began when man commenced to compare one fact with another, to classify phenomena, and to arrange his knowledge systematically. Order, method, system, are basic principles of science. The best description would, therefore, appear to be systematized knowledge of any kind which had been gained and verified by exact observation and correct thinking. The whole field of human knowledge is now methodically formulated and arranged into rational systems. Modern science may, therefore, be said to embrace all our exact knowledge. Its province is enormous; its subdivisions are limitless. Science takes no account of knowledge which is not exact. Many people acquire valuable information which they profitably use in business, but which they are unable to communicate or describe to others because they do not actually understand it. Farmers and flower growers often possess important practical knowledge of facts which are embraced by the principles of the sciences of agriculture, botany, and biology. But their practical knowledge is not true science. It is rather like an artist's intuitive impulse. It is not the result of scientific analysis, and there is no tangible, communicable residuum. There could be no science if men did not discover principles of knowledge which can be communicated to, and made available for use by others. Scientific knowledge must be stripped of all traces of emotionalism and personal convictions. True science is, therefore, depersonalized knowledge. The history of science shows how our exact knowledge has been developed along irregular paths but with progressive advances. There have been long periods during which little apparent progress was accomplished, which have been succeeded by others made memorable by brilliant discoveries. We must constantly bear in mind that many of the truths generally accepted to-day were doubtful or novel theories at some previous period. The history of science shows the enormous mental effort expended in testing and developing what now appear to us as commonplace truths. Basic principles like those of algebra, geometry, and the planetary motions were tested during several thousand years before they were finally accepted as true. The human intellect at the dawn of history was similar to what it is to-day. But it was not exercised as we exercise ours because it did not have adequate materials and opportunities. For the same reason science made slower progress in early times than it does now. Progress is cumulative. Each advance helps that which follows. The functions of a scientist are to struggle against individual views, and to provide an explanation of phenomena which may be accepted as true by other minds. Ascertained facts must be classified and then sequence and significance recognized from an unbiased viewpoint. The history of science is the written record of countless experiments, theories, and experiences of mankind which have been submitted to the tests of scientific methods. While it is true that science embraces all knowledge its real scope is limited to knowledge which is reducible to laws and can be embodied in systems. The human mind unites all knowledge by a single thread, but we have to chart and map it into larger and smaller divisions which we define by the methods, basic concepts, and plans used in developing them. We may now see how it is that the boundaries of any science are merely approximate. The general grouping of the sciences is likewise approximate. The first large group includes the abstract, or formal, sciences such as mathematics and logic. The other great group comprises the concrete sciences dealing with phenomena as contrasted with formal relationships. Chemistry, biology, physics, psychology, and sociology belong to the concrete group. At the beginning of history man is discovered observing the great phenomena of Nature and struggling to learn their laws and to explain them. Religion is both emotional and intellectual, and through these qualities it attracted primitive man while he was attempting to gather light on the riddles of the world. It was through religion that science was born. Recent researches into primitive beliefs have shown in a surprising manner the psychological unity of man. In all parts of the world, in all periods of history, and under all conditions, the minds of men, in their natural reactions against the basic factors of existence, operate in similar ways. There is a remarkable resemblance in the mental processes of men. The laws of thought appear to work automatically in all men. The minds of prehistoric people worked like those of men to-day. The impressions of the senses appear to be interpreted in similar ways by all peoples. Here is the explanation of the numerous resemblances we find in national histories, national folk lore, and national religions. They differ much in innumerable details, but possess many resemblances in their great fundamental conceptions. Normal man has always been religious. Mankind has always assumed definite attitudes toward the universe and this has resulted in the universality of religion. Early men the world over appear to have been as eager to learn the keys to the riddles of the universe as was the boy Longfellow sang about in the following stanzas: Nature, the old nurse, took The child upon her knee, Saying: "Here is a story-book Thy Father has written for thee." "Come wander with me," she said, "Into regions yet untrod; And read what is still unread In the manuscripts of God." And he wandered away and away With Nature, the dear old nurse, Who sang to him night and day The rhymes of the universe. And whenever the way seemed long, Or his heart began to fail, She would sing a more wonderful song, Or tell a more marvelous tale. Modern science has developed from this instinctive human desire to read Nature's story-book and understand her marvelous tales. Early struggles of mankind taught that human behavior must be regulated in accordance with rigid moral laws. This promoted the primitive social processes which were early concerned with religious beliefs as well as with magic and medicine. Two of the earliest beliefs universally accepted were that we possess souls and that our personality persists after death. These basic principles of faith have caused extremely beneficial results to follow in the development of knowledge. Some of the American Indians and other primitive peoples of to-day still live in the belief that the heavenly bodies, the sky, sea, and earth, as well as plants, animals, and men, all belong to a vast system of all-conscious and interrelated life, in which the degrees of relationship are distinguished by the degrees of resemblance. Religious beliefs were developed from struggles to conceive the inconceivable and discover the infinite. Religions led to studies of mysteries and ceremonies and rites. Magic developed and this also had its customs, dogmas, and rites. The difference between magic and religion was that the magician was consulted by his personal friends, whereas the holders of religious beliefs had a common bond uniting them in one strict form of worship. Magic was not systematized, while religion was a unified system of beliefs and practices relative to sacred things, and chiefly to the regulation of moral concepts and conduct. The intimate association of religion, magic, necromancy, and science continued until the early Greek era. There were many temples erected in Greece and dedicated to Æsculapius, the god of medicine. Cures were believed to be effected through the valuable offerings made to the god by patients and their friends. It was thought that the ways to health would be indicated to them by the god through dreams. Recent investigations of the representative ceremonial rites of the aboriginal peoples of Australasia and of North and South America have yielded a remarkably rich fund of information on the causes and conditions which operated in prehistoric eras in developing the mental, moral, and physical sciences. Some of the most romantic stories ever developed by the human intellect are to be found in recent scientific works dealing with the history and principles of the tribal customs, ceremonies, and religious rites of primitive peoples. The early chapters in the history of man's mental development and the evolution of science from distant origins in mystic forces, through magic and necromancy to religion and philosophy, must give abundant pleasure to all thoughtful persons by showing how it came that the high state of civilization now attained was brought about by slow processes, operating through immense periods of time and blossoming only during the past two or three thousand years. A study of these stories cannot fail to show how intimately science has been associated with religion, why every normal individual is essentially religious, and why the continuation of our civilization, and the very existence of the human race, are absolutely contingent upon the recognition of the moral laws, in the future as in the past. The history of science establishes the fact that moral sanctions, which require religious ceremonies to keep them vital, are the essential bases of human progress. CHAPTER II PRIMITIVE MAN AND EARLY CIVILIZATIONS The development of scientific history has not followed a uniform course. Progress has been rhythmic. There has been always a reaction coming in the steps of brilliant discoveries. Periods of feverish experimental activities have been succeeded by others during which little apparent progress was made. Such dull intervals seem to have been necessary for developing, formulating, classifying, and testing the innumerable details and inferences that the discoveries of the active periods produced. While mankind in general has contributed to the total of our intellectual treasures, some races have been more active in this way than others. For this reason it is advisable to briefly survey the more recent discoveries about the ancestors of existing peoples. Indo-Malaysia, parts of central Asia, and the valleys of the Tigris and Euphrates rivers in Mesopotamia are variously credited with having been the cradle of the human race. It should be understood, however, that we are only permitted to speak authoritatively of existing races, because the land forms of the earth have undergone such remarkable changes that we can know little definitely about the earlier periods of human history. For the purposes of the history of science, while bearing in mind these qualifying suggestions, we may accept the statement that man's ancestors originated in proximity to India. It was around the waters of the Persian Gulf that the earliest known civilizations arose. The people who founded them came from central Asia. They had reached a considerable degree of culture, which suggests that they themselves came from earlier centers of civilization. The study of prehistoric antiquity is termed archæology. Its principal periods have been divided, for convenience, into the Stone, Bronze, and Iron Ages. Each of these is distinguished by the substances used for tools. In the Stone Age men used stone spearheads, arrows, and knives, whereas in the Iron Age similar things were made of iron or copper. The science of mankind is known as Anthropology. It deals with the innumerable steps in the evolution of mankind from remote periods, and with the primitive development of the arts, sciences, and religion. Yet it is one of the youngest of the sciences. One of its essential teachings is that heredity and racial predispositions play, and always have played, more important parts in man's evolution, and in the development of civilization, than environment and education. Hereditary tendencies, such as the religious, moral, and æsthetic instincts have been indispensable in preserving and developing all the races of mankind. Moral discipline has been the chief factor in self-control, and therefore in civilization. It is because the moral sense has proved so beneficial to the human race, and is the most powerful of our instinctive desires, that mankind always has been and must be religious. It controls man's knowledge, desires, and will, and has dominated the race since our early ancestors began to think. When we recognize this fact we can readily see that anything which tends to oppose the moral or ethical sanctions, or detract from religious beliefs, is injurious to civilization and human progress. The histories of religion, ethics, and æsthetics plainly develop the rôles which have been played by moral self-discipline in the protection and development of mankind, as well as of knowledge and science. The moral control of individuals acts also upon society generally, and upon whole racial and national groups. The ethical ideals assist each individual mind to realize its own end and at the same time tend to influence the tribal and social mind to attain a common end. This great moral, instinctive force, which has played such an immensely valuable part in developing civilization and science, is known as the human social and national conscience. It acts both individually and collectively. European races have been divided into classes corresponding to the prevailing cephalic indices. The longheads are grouped as the Nordic, or Baltic, subspecies, because they were formerly numerous around the Baltic countries. People of this group are distinguished by tall statures, fair skin and hair, good physique, and light colored eyes. These peoples include the Scandinavians, Anglo-Saxon, and certain important Teutonic groups, as well as Asiatic peoples who are known as the Aryans. [Illustration: Copyright, Ewing Galloway MODEL OF THE SAILING VESSEL "SANTA MARIA," THE FLAGSHIP OF COLUMBUS] [Illustration: CURTISS NAVY RACER, THE AIRPLANE THAT WON THE PULITZER RACE OF 1921] [Illustration: U. S. ARMY DIRIGIBLE ON A TRANSCONTINENTAL FLIGHT] The most important rôles in the development of modern civilization, art, industry, and science have been played by representatives of the Nordics. The Iberian, or Mediterranean, subspecies, ranks next in importance. The peoples of this great racial division originally occupied the countries between the northern Atlantic coast of Africa and the confines of the areas of the Nordics around the northern provinces of France. They spread down the Mediterranean and over large areas in Asia. Their skulls are long, but differ from those of the Nordics in their absolute size. Their stature is lower, and weaker than that of the Nordics, while their hair, eyes, and skin are dark or black. The Welsh, the Moors, and the early Greeks are chiefly classed with the Mediterranean group. The Carthaginians, Phœnicians, Egyptians, and Etrurians were members of it. The roundheads comprise the Alpine subspecies. This is the strongest numerical group to-day. It is characterized by small round heads, short bodies, dark hair, and dark eyes. It is of Asiatic origin and includes the Slavs, modern Greeks, Italians, Germans, Austrians, Swiss, the pre-Nordic Irish, French, and Belgians. The first Alpine invasion of Europe began about 10,000 B. C. There were many subsequent ones through the plateaus of Asia Minor, the Balkans, and valley of the Danube. They reached England about 1800 B. C., and formed small colonies in Ireland, the descendants of which now call themselves Celts and are clearly distinguished by the characteristic Alpine indices. This race is now so well acclimatized in Europe that most of its Asiatic traces have been lost, and its round skulls and dark eyes and hair are the only reminders of its Mongolian origin. Members of each of these three great racial groups of mankind have throughout the ages contributed to the development of the sciences and arts. The Nordics began to appear in European history as agricultural tribes, speaking Aryan languages, like Celtic and Welsh, who swept down from the north and pushed the earlier settlers back through their irresistible arms, which were made of bronze and later of iron. The earlier settlers were still furnished with arms and implements of the Stone Age. There was a much older intellectual people than the Nordics settled in Europe. The people of this race, about whom we have learned through recent archæological researches, are known as the Cro-Magnons. They lived between 25,000 and 10,000 B. C. Their skulls were distinguished from those of the Nordics by their pronounced cheek-bones and broad faces. Their culture, as their favorable cephalic index would suggest, was of a high character. Numerous drawings and art works of theirs, which have been preserved, place them among the world's superior peoples. Soon after the settlement of the Cro-Magnons in Europe, and their intermarriage with the earlier settlers, their physical development and stature began to decline. They were finally absorbed and destroyed by the inferior peoples among whom they dwelled. Their disappearance, like that of the ancient Greeks, who appear to have been the most intellectual people the world ever produced, shows how the upward development of human physical and intellectual qualities is constantly injured by the contacts of superior and inferior races. The scientific discoveries made prior to the Iron Age, or about 2000 B. C., were not numerous. The struggle for life was so intense that few had opportunity for contemplation and philosophic reflection. It was subsequent to the discovery of the basic principles of metallurgy, in the Iron Age, that science began rapidly to advance. The benefits bestowed upon mankind by the employment of metals reduced the sharpness of life's struggles, permitted and instigated reflection, and provided means for experimentation. Modern history begins with the peoples of Mesopotamia. There were cultured peoples east of the Tigris and Euphrates, in Persia, India, Mongolia, Tartary, and China before the founding of Babylon. But we are more instructed about the Babylonians and Assyrians than about earlier Asiatic races. The Babylonians and Assyrians appear to have originated in central Asia and to have migrated to Arabia about 10,000 B. C., and perhaps earlier. They were well settled in Arabia before the Egyptian pyramids and other Semitic memorials were planned. They brought with them from the farthest Orient many important contributions to civilization and culture, and developed many others. These were religious, philosophical and keen commercial peoples. They shaped the organization of modern religions. The Babylonians reduced the world of gods to a single system with classifications distinguishing between major and minor deities, and between those of heavenly, or stellar, and earthly habitats, and those of time and space. They developed many religious myths of the Creation, the Flood, Paradise, and others which were subsequently embraced by other religions. Both the Babylonians and Assyrians composed beautiful hymns, prayers, parables, and religious tales, and had numerous elaborate religious customs, rituals, ceremonies, and festivals conducted by priests, nuns, and acolytes. Anu, or Anum, the God of Heaven, was the principal Babylonian deity, while Ashur was the leading god of the Assyrians. Religious studies and rites occupied a large portion of the time of these peoples and, consequently, their temples, monasteries, schools, and other religious buildings were large and numerous. Their architecture was elaborately artistic. This was one of their incentives to scientific invention. They made important discoveries in all the basic physical sciences, like chemistry, physics, metallurgy, and mathematics, to enable them to improve their buildings and to embellish them with paintings, pictorial tiles, and fancy metals and textiles. They had excellent professional men, artists, jurists, bankers, contractors, and scientists. They were fond of literature and founded extensive libraries. Music and musical instruments were very popular with them. Their cuneiform writings, as disclosed by numerous beautiful stone and porcelain tablets which have come down to us, were excellently done. The fragments of literature, laws, and religious policies that we are acquainted with indicate that the numerous Babylonian and Assyrian settlements in each great empire possessed social and political conditions similar to those of our days. Science and art were then sufficiently advanced to enable these ancient people to live as agreeable, moral, and legally secure lives as those of any subsequent peoples. The Chinese appear to have been making similar progress to that of the Babylonians about the same period. It would seem that both these peoples were in contact with a similar but earlier cultured race in central Asia. Although the early Chinese were a religious people, they appear to have been more philosophical than the Babylonians. This enabled them to make further progress in the abstract sciences. In subsequent years they made rapid strides in the physical sciences, as will be shown later. The Egyptians came into prominence toward the end of the Babylonian and Assyrian empires, and for many centuries played a great rôle in developing civilization. The numerous benefits which they bestowed upon the world by their researches in science and art are not fully appreciated. Early history pictures two great Asiatic races struggling for supremacy in India. They were the Aryans, a fair-skinned people, and the Dravidians, a colored people. The Aryans succeeded in displacing the Dravidians in the great plains, upon which they settled and developed large cities, important world commerce, and contributed great art works and scientific and philosophical discoveries to the world's stores. The Dravidians retired to the hill country, where their representatives still live. The minds of the various Indian peoples have always been strongly philosophical. This led them to the development of numerous religious sects and philosophical systems, and they made important mathematical discoveries. While the scientific bent of the ancient Greeks was of a concrete nature, which tended toward geometrical proofs for scientific problems, that of the ancient peoples of India was toward numerical symbolism and arithmetical proofs. We find that when the Greeks were developing geometry the Indians were contributing to arithmetic and algebra. The Chinese closely resembled the ancient Indians in the philosophical tendency of their minds; but, owing perhaps to the different conditions under which they lived, they were more concrete in their ideas. They also made progress in mathematics and developed medicine, chemistry, metallurgy, and many of the sciences which were applied to commercial and industrial uses. The progress made in mathematics in China was transmitted to Egypt, and therefore to Europe, through India. Among early Chinese discoveries in mathematics were methods of solving numerical equations and the development of magic squares and circles, which gave a great stimulus to studies in geometry and astronomy. The Arabs, Greeks, and Romans took up the discoveries of the Asiatic peoples, and the Egyptians enlarged them and passed them forward to us. The Arabs solved cubic equations by geometrical means, perfected the basic principles of trigonometry, and made great advances in mathematics, physics, chemistry, and astronomy. A survey of the early history of science indicates that from the remotest period man was engaged in grappling with the great principle of causation. Progress was necessarily slow at first on account of the scarcity of tested data. Then it became more rapid. Soon after the founding of the great city of Babylon we find that the Babylonians were possessed of enough knowledge of the arts and sciences to enable them to become world traders and great industrial undertakers. They built many cities and lived highly civilized lives. The history of modern science may very properly be dated from the building of Babylon. CHAPTER III PRE-BABYLONIAN SCIENCE The transcending wonders of the phenomena of the heavenly bodies attracted the attention of primitive man at an early period of his intellectual development. The succession of day and night, the phases of the moon, comets, meteorites, the eclipses of sun and moon, the recurrence of the seasons were observed and recorded. In this way, through long uncivilized times, many scientific facts were noticed and handed down by tradition, and probably were among the first scientific data collected. We have no means of determining when the primitive science of astronomy became systematized, although there are reasons for believing that it was roughly outlined at a remote date. There was a tradition among the Babylonian priests that their astronomical observations and records went back to a period of more than 400,000 years. This statement was believed by the people of antiquity, and was made to Alexander the Great during his Indian campaign. Astronomy appears to have been developed into an organized system by the primitive peoples of central Asia. It was carried to China, India, and Arabia by learned travelers. There were government astronomers in China before the year 3000 B. C., and history records that two of these officials, named Ho and Hi, were beheaded in the year 2159 B. C. for being careless in their work and failing to issue a timely prediction of a solar eclipse. Chinese history also relates that the Emperor, in 2857 B. C., issued an edict recommending the study of astronomy. From these and other historical references we learn that nearly 5,000 years ago astronomical science was not only well developed, but that its educational value was recognized. While attention was being given to the study of astronomy in China, this science was independently developed in India. The astronomers of India invented a different system from that of the Chinese, and compiled numerous astronomical tables which were published and widely used as far back as 3102 B. C. These early astronomical studies resulted in the division of time practically as we know it to-day. The Babylonians had a week of seven days. The days bore names of the planets and were divided into hours and minutes. Days were combined into months and years. The Babylonian and Chaldean astronomers, like those of China and India, were important men and were credited with great learning. The Babylonian month began on the evening when a new moon was first observed. An adjustment was made necessary between the months, owing to the fact that the actual lunar interval is about twenty-nine and a fraction days. Numerous astrological observations were made with the view of obtaining data to facilitate the monthly adjustments. The taking of these observations was made easier by maps of the heavens which were recorded on baked clay tablets and prisms. Similar maps of the world, with positions fixed by astronomical observations, were likewise made in Babylonian times. The usefulness of astronomical observations and predictions led to the belief that they could be employed with advantage for wider purposes. The astrologers endeavored to deduce omens and forecast horoscopes. In order to facilitate their calculations, the astrologers invented calculating and time-dividing machines. Tablets from the royal library at Nineveh indicate that Chaldean astrologers possessed mechanisms which divided the hours of the day by mechanical means. These were forerunners of modern clocks and timepieces. These early scientists represented the earth as a vast circular plain, intersected by high mountain ranges and surrounded by a large river, with other mountain chains which lost themselves in an infinite ocean. The heavenly vault was believed to be supported by the highest peaks of the outlying mountains. It was owing to the peculiar nature of this cosmogony that the pre-Babylonians and Babylonians were unable to develop a satisfactory mechanical view of the world. The world had to wait for an adequate mechanical theory before general knowledge could be advanced, so that men like Newton and Laplace could correct the errors of early theories and furnish a sound working hypothesis. The advancement of science requires methodical observations and the use of the highest powers of the imagination. It is thinking in picture-like figures that supplies primitive reasoning. While pure reasoning deals with abstract, verbal images, the more concrete picture-thinking deals with object-images. The differences between thinkers and dreamers is chiefly in the way their minds act. But even thinkers are supplied with thought material by the elementary mental operation of picture-thought, dreams, or dream-thinking. Science needs the active use of the imagination to anticipate experience and suggest the issues of a process in course of action. Most great inventions, and probably all primitive inventions, were stimulated by imagination. But the imagination, unless skillfully directed, is liable to numerous errors. That is why in all ages there has been much error in connection with knowledge. There could, however, be little or no progress without imaginative work. It is only within very recent years that the modern sciences have been stripped of much absurd matter derived from crude imaginative work. When we bear this in mind, we have the key to the part played by ancient myths, magic, and ceremonies in developing civilization. The term magic is derived from the Persian term for priest. The magi, or priests of Zoroaster, their religion, learning, and occult practices had important world-wide effects just before the Babylonian era. Magic is a pioneer of religion, philosophy, and science. Medicine was benefited, in some ways, by the priests seeking means for dealing with the work of the spirits of evil. Chemistry and metallurgy were also advanced, and new realms of knowledge were opened even by magicians. The magic of the Babylonians survived their empire. It was handed over to the Egyptians and contemporary peoples, and was in turn passed down to the magicians and alchemists of the Middle Ages, and to the dramatists, poets, and novelists of all ages. The accumulation of scientific facts was greatly facilitated by the improvements made by the Babylonians in the manufacture of earthenware tablets, scrolls, and prisms. Beautifully drawn cuneiform picture signs recorded on these all the knowledge of the day. These stonelike records were filed away in many monasteries and libraries. Subsequently, letters were invented, alphabets were formed, and writing displaced the hieroglyphic symbols. The invention of alphabets made reading easier. This resulted in giving an impetus to education which has had cumulative effects right down through the ages. We are now in a position to realize why scientific discoveries were made very slowly, and at long intervals apart, in early times. Facts had to be accumulated, studied, grouped, and compared. Accounts of these studies had to be pictured and stored away for future use. Only exceptionally learned men did this. But when alphabets were invented and education increased, numerous minds became active and there was a great extension of thought, experimentation, and philosophical contemplation. This was followed by the establishment of new religious houses, schools, and philosophical academies, at all of which the ablest men of the day emulated the scholars in formulating theories and making inventions. Soon after the perfecting of cuneiform writing in Babylon, characters were devised for representing numbers. A vertical, arrowlike wedge represented the figure 1, while a horizontal wedge stood for 10. A vertical and horizontal wedge, placed together, signified 100. Other arrangements of these characters meant that they were to be multiplied, subtracted, divided, or added together. In this simple manner all kinds of arithmetical results could be recorded. The Babylonian mathematicians were familiar with decimals, integers, and fractions, and their tables and records of astronomical and engineering calculations reveal a remarkably high degree of mathematical ability, indicating that peoples who preceded us by several thousands of years were familiar with the more important calculations requisite in trade and industry as well as for astrological computations. Babylon was a great world metropolis. It occupied a position similar to that occupied by London to-day. Its merchants were engaged in world-wide commercial operations which needed good systems of bookkeeping and accountancy. These, in turn, presupposed a highly developed arithmetical system. Practically all the arithmetical calculations used in commerce to-day were employed by them. Their accountants, like those of China to-day, used the abacus, or calculating machine. A lucid illustration of the accuracy of ancient calculations, the efficiency of their reports, and the confidence with which they executed intellectual duties is afforded by the following translation of a Babylonian astronomer's official report: "To the King, my lord, thy faithful servant, Mar-Istar. "... On the first day, as the new moon's day of the month of Thammuz declined, the moon again became visible over the planet Mercury, as I previously had predicted that it would to my master the King. My calculations were accurate." The records of Babylon furnish us with a wealth of documents of this character. The numerous peoples of India have always been divided into castes. This has resulted in the pioneering work in science falling to the priests. However, the principal priests were among the most intellectual men of each generation and, as they traveled in search of instruction, India was always in contact with the progress made in China, central Asia, and Babylonia. These great centers of ancient learning progressed together. The Indians were able mathematicians and discovered and developed at an early period what is now known as "Arabic notation." In this work they were assisted by the Babylonians. The Indians, like the Chinese and Babylonians, solved problems in interest, discounts, partnership, the summation of arithmetical and geometrical series, and determined number changes in combinations and permutations with ease. They were also proficient in algebra, the extraction of the roots of numbers, various classes of equations, and the principles of trigonometry. The Chinese have always been good mathematicians. It is probably due to this fact that they have at all times been such able traders and bankers. We are not so familiar with the works of Chinese mathematicians in pre-Babylonian times as we are with the Indian; but the references of contemporary writers indicate that the Chinese scientists were as able and active as their contemporaries. We have remarked the high degree of perfection which was attained in the Babylonian era by scholars in science and mathematics. Similar perfection was attained in art, industry, law, and medicine. The wonderful law work that has come down to us under the name of the code of Hammurabi indicates not only the extensive progress which had been made in law, but incidentally through its references the progress of agriculture, industry, commerce, and business. Many references in the Hammurabic code, written about 2300 B. C., show that the medical profession had attained considerable advance in Babylon. Surgeons were daring operators. They commonly performed operations for cataract. Many of the common major operations now performed by surgeons were also done by the ancients. They were experts at setting fractured bones. The physicians made effective use of drugs. Many drugs employed to-day were known to them. The discoveries of the early oriental nations were collected and developed in Babylon. The entire fields of science, mathematics, geometry, agriculture, astronomy, philosophy, and art were focused in Babylon and handed down to the Egyptians and the Greeks. Much credit that is given to ancient Greece should be shared also by Babylon. It was from Babylon that Greece obtained the principles of its civilization, arts and sciences. Even Greek architecture and sculpture were originally derived from Babylon. CHAPTER IV EGYPTIAN SCIENCE The early civilization in Egypt developed in the ancient cities of Thebes and Memphis. Authorities on the dawn of history in Egypt are unable to definitely account for the origins of the various peoples who have ruled the land. One school contends that the early negroid inhabitants originated in Africa. Another school opposes this view and suggests an Asiatic origin. Each of these schools can marshal facts to sustain its contentions. The truth is that Africa was inhabited at such an early period that we are unable to fully trace back the movements of its races. Man was divided into species and subspecies at a very remote period. The dominant peoples in each country, in each era, were the successful contestants in long conflicts for supremacy. Many races have vanished without leaving any traces beyond reversional strains which still come to the surface at times in families living to-day. The laws of evolution, only recently deciphered, are the sole means we possess for learning about many of the long-perished species of men. A few races, too weak to ever gain supremacy and themselves to occupy districts, or countries, have survived by dwelling among stronger races. The Ainus, in Japan, and the Jews in Asia and Europe, are well-known examples. [Illustration: MODEL OF AN EARLY ELECTRIC MOTOR The original was invented by M. H. Jacobi in 1834 and was used in 1838 to propel a boat on the Neva at St. Petersburg.] [Illustration: MODEL OF AN EARLY TURNING LATHE This mechanism was invented by Thomas Blanchard in 1843. He also invented a lathe for turning gun barrels.] [Illustration: Copyright, Underwood & Underwood AN EDISON PHONOGRAPH OF 1878 The sound record was made on a sheet of tin foil vibrated by the voice.] [Illustration: WHITNEY'S COTTON GIN This device, invented in 1793, revolutionized the cotton and cotton manufacturing industries.] Egypt, owing to its remarkable geographical situation between Asia, Europe, and the vast continent of Africa, has been a great highway for race migrations. Many peoples have lived and ruled there and passed on before incoming tides of new and more vigorous peoples. Each race, undoubtedly, during its residence in Egypt contributed to the general fund of Egyptian knowledge and customs and assisted in the development of science. The tombs of Thebes have given us bodies of ancient Egyptians of more than six thousand years ago. At that time the people were characterized by the Grecian type of profile. They resembled the contemporary active peoples in India and Arabia and did not differ much from the Egyptians of our day. The incoming streams of people who settled in the Nile valley, both Asiatic and negroid, changed the appearance of the Egyptians at different times by intermarriage, but when their vigor waned and they were crowded out by other peoples, the Egyptians assumed their regular Semitic characteristics. Egyptian history really begins with the old kingdom dynasties, about ten thousand years ago. The tombs of Abydos have furnished material for accounts of this early period. There were eight powerful kings in the first dynasty and all of them contributed to the advancement of civilization. Abydos, and later Memphis, were their principal cities. They ruled in great luxury and were patrons of the arts and sciences. The art works, sculptures, and carvings in ivory and ebony of this era speak in eloquent terms of the taste and high mental powers of the people. Modern museums are well supplied with relics of those times, which illustrate the degree of civilization attained by the Egyptians at the beginning of their history better than any written account. The early Egyptians adopted the sciences, arts and customs of the Babylonians. With these as a basis the priests and learned men experimented and made many independent researches and discoveries. The pyramids, erected near Cairo 3000 B. C., indicate the high degree of culture which the early Egyptians had attained. These renowned monuments to the kings were scientifically designed and constructed to exist for all time. In order to contribute to their usefulness, they were planned so as to exhibit correct geometrical forms and indicate the cardinal points of the compass and the positions of certain astronomical bodies. The details of their construction disclosed much mathematical, geometrical and physical knowledge, and their actual building called for not only an all-around mechanical skill but a high degree of engineering ability. They were constructed of various materials. Some large granite blocks were used in the outside walls and these were brought from the upper Nile. They were towed down the river on barges and were lifted into the positions in which they are found to-day. Various mortars and mortar mixtures were employed in binding the brickwork and masonry. These called for a good knowledge of chemistry and physics. The arches and sloping walls of some of the larger pyramids show how well the architects and engineers of the day knew their professions. With similar means in their possession, the best professional men of the present day would find it difficult to get such splendid results. In the past few years, lapidaries and gem-workers have learned to cut stones and gems with steel disk-wheels, the cutting edges of which are furnished with carborundum or emery powder or insets of diamonds. The pyramid builders knew this method of sawing and cutting stones. They actually employed bronze saws set with diamonds to cut the huge blocks of granite, syenite, diorite, and basalt used in the construction of the pyramids. They also set the cutting ends of their rock drills with diamonds, and bored rocks as we do to-day with diamond core drills. The art of making these tools was afterward lost. Only within the past half-century have mechanical rock saws and diamond drills been reinvented. This brilliantly indicates the inventive ability of the engineers at the dawn of Egypt's history. The builders of the splendid monument of Rameses II in the Memnonium, at Thebes, which weighs 887 long tons, transported the huge stone by land from the quarries at E'Sooan, a distance of 138 miles. Such tasks appear never to have deterred early Egyptian engineers and architects. They were so sure of their ability to carry their great operations to satisfactory completion that they never hesitated in agreeing to the severest penalties for nonfulfillment of contract. Their cranes, levers, wedges, rock drills, pumps, air blowers and compressors, and building tools all showed how well mastered was their knowledge. Their quarrying methods were similar to those used in the best practice to-day. When huge blocks and slabs of stone were needed the required dimensions were marked on the rock and channeled out. Metal wedges were forced into the channels and struck at once by a large number of hammers. The constant vibration, in time, broke off the stone with clean-cut surfaces. When these were to be carved into statuary or ornamental shapes it was often done at the quarries, so as to reduce transportation difficulties. Water transportation was used when possible. When the stone had to be moved over the desert sands it was lifted by cranes and set on sleds drawn by men or animals, or driven forward by levers, just as heavy steel machinery is moved by modern engineers. The principle of the siphon was known to the Egyptians at an early period. It was employed daily in many homes for supplying water and for drawing off wine from barrels and tanks into domestic utensils. Its principal use, however, was in civil engineering works. Siphons were constructed on a large scale for furnishing water to villages, draining land for farming, and for irrigation purposes. They were built, in many known instances, for carrying large quantities of water, in high lifts, over hills. Herodotus tells us that the science of geometry was discovered by the Egyptians as a result of the necessity for making annual surveys of the farming lands in the Nile valley. When geometry was established as a practical science, land and astronomical surveying were simplified and many branches of mathematics were enlarged. The science of marine surveying was also developed and this led to a great improvement in map-making and in geography, in which the Egyptians became famous. The skill attained by the Egyptians in land surveying required accurate surveying instruments. These were invented at an early period. The Greeks claim the invention of the theodolite and similar instruments, but Egyptian history shows that gnomons, surveying compasses, and levels were used by Egyptian surveyors long before the Greeks began to study the learning of Egypt. Astronomical science made great progress in Egypt. The theory attributing to the sun the central place in our planetary system, now called the Copernican theory, was known and used in Egypt. They were familiar with the obliquity of the ecliptic, and knew that the Milky Way was an aggregation of numerous stars of various sizes. They understood that moonlight is simply the reflected light of the sun. The movements of comets, the positions of the principal stars and stellar constellations and other astronomical phenomena were studied and charted on astronomical maps or recorded and forecasted in astronomical tables. The discoveries made by the Greek scientists naturally stimulated philosophical thought, which in turn reacted upon scientific experimentation and led to a broadening of the scope of general research work. We are dependent upon the pictorial records of early Egyptian times for descriptions of the instruments and machinery employed and these are not always clear. They indicate, however, that the Egyptians quickly learned the sciences developed by the Babylonians and other Oriental peoples and improved them. Their knowledge of astronomy, mathematics, geometry, chemistry, physics, medicine, and agriculture was extensive. The priests and learned men taught the pure sciences and constantly experimented; the engineers, architects, surveyors, and mechanics applied the sciences to the arts. In one of the records of an early dynasty the father of a student sailing up the Nile to begin his studies in one of the leading scientific schools gave this advice: "Put thy heart into learning and love knowledge like a mother, for there is nothing that is so precious as learning." The Mesopotamian peoples, as we saw in the last chapter, considered the stars and principal heavenly bodies as deities. The Egyptians did not do this, although they looked upon the heavens as the abode of all pious souls. Their astronomical knowledge at the time of the establishment of the New Empire at Thebes, about the year 1320 B. C., was remarkably extensive. The Egyptians divided time in accordance with the course of the sun into periods of 365¼ days, and these were divided in accordance with the course of the moon into periods of about 29½ days. Thus the basis of the system of years and months used by us was perfectly understood by the Egyptians. The science of medicine was developed at a very early period in Egyptian history. The various divisions of physicians, surgeons, pharmaceutists, veterinarians, and dentists organized by the Babylonians were retained by the Egyptians. Many names of distinguished practitioners have been handed down. Nevertheless, their anatomical knowledge remained poor, and there were many superstitious practices connected with medicine. The various medical manuals which have been preserved show that the Egyptian physicians studied diagnosis with modern thoroughness. They were aware that an exact knowledge of each disease, obtainable only by a complete study of the symptoms, was necessary before a correct treatment could be prescribed. When the magic and the superstitious dressings are abstracted from Egyptian medical works and prescriptions, we find that the broad principles were sound and efficient. They were developed along lines similar to those of modern times. Mathematics attracted much attention in Egypt. The learning of Oriental countries on this subject was readily absorbed by the Egyptians. The Greek historians were so surprised at the efficiency of the Egyptians in this branch of knowledge that they almost unanimously asserted that the mathematical sciences originated in Egypt. The pyramid base lines run in the direction of the four points of the compass, and were determined by correct astronomical methods. The astronomers and surveyors were skilled in trigonometry. Fractions were known to the Egyptians, who were taught in the schools of Babylon. The modern x, representing an unknown factor, was known to the Egyptians under the name of "hau." Quadratic equations were employed by them. The problem of finding x and y, when x² + y² = 100 and x:y = 1:¾, one of the earliest problems of this character known, was found in a papyrus at Kahun. The problem was stated as follows: "A given surface of, say, 100 units of area, shall be represented as the sum of two squares, whose sides are to each other as 1:¾." The papyrus gave the working out of the solution. Many similar problems are given in mathematical works and papyri. They show the proficiency in mathematics that Egyptian scientists had attained at a remote period. But their methods of expressing mathematical problems were crude and, consequently, involved much tedious labor in finding solutions. There can be little doubt that if effective mathematical symbols had been devised the abstract sciences would have made even greater progress than they did in early Egypt. When we study the complicated solutions of algebraic problems made by the Egyptians, owing to the lack of simple symbols, we can appreciate how greatly modern mathematical science is benefited by the devices now employed for expressing quantities, variations, and operations. The Egyptians were expert in applying the discoveries of science to the arts. The Nile made their country potentially rich in agriculture, and they devoted much attention to inventing such things as single and double plows, rakes, and other agricultural machines, many of which were drawn by oxen, donkeys, and other animals. Reaping was done with sickles and scythes. Not only was irrigation understood and widely practiced, but the importance of fertilization was recognized. The farmers understood the preservation of meat, vegetables, and foodstuffs generally, by drying or pickling. They also brewed beer and made wines, vegetable and seed oils, and alcohol. The selection of breeding animals and the principles of variation were understood and employed for developing particular breeds of cattle and farm stocks. The papyrus reed grew luxuriantly in Egypt and this resulted in the discovery of paper making, weaving, thread making and many textile methods. These industries led to the invention of looms, rope and twine twisting appliances, flax weaving and other machinery. The linens and cloths made by these machines have never been excelled. Dyeing was developed with the textile industries. As the skies of Egypt are bright, the people in all ages have had a fondness for brilliant colors. The call for bright textile colors led to a considerable development in the chemistry of dyes and dyeing. Vegetable and mineral dyes were used. Dyes were not always applied to the whole pieces of goods, but stenciling and other methods of patterning were used. The highly organized artistic skill of the people demanded art-designed textiles and the manufacturers responded with beautiful and rich materials. The fur and feather industries became important at an early period. The Egyptians were fond of beautiful ornamental skins like those of the panther or gazelle. Such skins were manufactured into numerous domestic articles, made into clothing or used as rugs, mats, and seat coverings. Skins not valuable for art purposes were sent to the tanners to be converted into various kinds of leather. Tanning was highly developed, and the tanners turned out leathers which are to-day admired for their excellence. The tanners carried on their industries by chemical processes similar to those in use to-day. The scarcity of wood in Egypt led to the invention of various substitutes. One common substitute was a kind of _papier mâché_. This was manufactured out of linen, wood or vegetable pulp and various kinds of paste. When it was used for art work the molded forms were covered with lacquer or various kinds of stucco. Very beautiful objects were manufactured from these substances, which indicate that the artists possessed a wide practical knowledge of physical and chemical principles. Chemical knowledge was also well shown in their manufacture of glass. They excelled in this industry. All kinds of glass were made and decorated by staining and glazing. The glassmakers were able to imitate precious stones in glass and their glass-bead and enamel work has never been excelled. Some modern chemists express the opinion that glass making was carried to a greater degree of perfection in Egypt than any modern nation has attained. Egyptian porcelains were also finely executed. These were enameled, stained, and decorated in numerous ways. The colors, glazes, and art mediums employed by the artists in pottery and porcelain necessitated a wide chemical knowledge. Some of the pigments employed both in glass and porcelain ornamentation were made from metals. Their use required a knowledge of metallurgy. Metals like lead, nickel, manganese required fluxing and refining before they could be secured in a state sufficiently pure to be used as bases for colors. Not only did the artists know the value of many metallic oxides, but they understood how to secure the tints resulting from blending different oxides, and by acting upon metals with acids, just as they acted upon vegetable and metallic dyes with acids to get rare tones in linen dyeing. Mordants were employed in dyeing cloths and these were acted upon by acids and alkalies to produce various colors. We are dependent upon the relics which have been preserved for our knowledge of the chemical and physical learning of the Egyptians. No chemical books of theirs have come down to us, and inferences must be drawn from the results seen. In carrying out metallurgical operations, the Egyptians employed small blast furnaces and melting pots. Air was compressed by bellows and conducted into molten substances by pipes. The methods of metal working, melting, rolling, forging, soldering, annealing, and chasing were similar to common methods in use in modern times. The Egyptians were a practical people. They made wonderful progress in the industrial arts and learned enough of scientific principles to enable them to deal with much success with the mechanical, agricultural, astronomical, medicinal, and chemical problems encountered. But, like the Babylonians, Assyrians and other Oriental peoples, the Egyptians did not systematize their sciences. Their investigations were always carried out with practical objects in view, and when the objects were attained the experiments ceased. They never discovered a true scientific method. That was left to be done by another people who were long students of Egyptian science and who, taking all the learning of Egypt, worked out from it, as a basis, the principal sciences as we have them to-day. The Greeks took the torch of scientific progress from the Egyptians, organized learning, and passed it on to the Romans and other peoples in sound, effective and augmented forms. The Greeks idealized and systematized scientific principles, whereas the Egyptians and earlier peoples rested content with the results they could obtain by their practical efforts. We will find that, throughout the history of science, progress has always been made by similar reactions between peoples possessing the one a practical, the other a philosophical genius. CHAPTER V FOUNDING OF SYSTEMATIC SCIENCE IN GREECE The world is indebted to the Greeks as much for science as for art and literature. The idealistic spirit of ancient Greece invested scientists as well as poets, artists, and thinkers generally. But the Greek scientists were students in the great schools of Egypt and brought much of their knowledge from that country. The greatest contributions made by Greece were in the nature of methods and analysis. They were led to these by the tendencies of the Greek mind to abstract thought and philosophical investigations. They soon recognized that science is knowledge gained by certain methods of abstraction. Data had to be systematically collected, digested, classified, and impartially studied. The results of such studies had to be assembled and expressed in the most useful forms. Progress had to be made by the trial and error method and the results of experiments tested by synthesis as well as analysis; by induction as well as deduction. The Ionian philosophers were the first to break away from the mythological traditions surrounding the principles of Egyptian and Asiatic science. Thales of Miletus about the year 580 B. C. taught that there is an essence, force, or soul in all things. This universal principle of activity is superhuman. Seeking to find of what the world is made, he arrived at the idea that water, or moisture, is the basic element. All matter, he said, is water in various forms and combinations. Here we see scientific knowledge sought with a definite aim and with unity of purpose. None of the earlier peoples had ever attempted to approach knowledge in this logical and fruitful manner. When the learned Babylonians were asked what the earth was they simply said: "When the world was created, Marduk, the sun god, took Tiamat, or Chaos, and divided her. The sky was formed above and the earth below." And the Egyptians answered the question in a similar way by saying: "When the world was created, Shu tore the goddess Nuit from the arms of Keb, and now she hangs above him and he is the earth." It was this kind of statement that Thales cast aside. He sought for more concrete definitions. Customary beliefs were not acceptable to him; his knowledge must be based on reason. Here we see the dawn of a new scientific spirit and the beginning of a new method of investigating knowledge. The world was introduced to a new field of intellectual activities. The theory of Thales was studied by other Greek philosophers. But Anaximander, a friend of Thales, rejected it, and in its place suggested that there is one eternal, indestructible substance which constitutes the basis of matter. This was not water but an infinite eternal motion. Water is subjected to extremes of temperature. Under such conditions nothing could have been stable enough to constitute matter. A primary substance must be free from warring or antagonistic elements. The world arose, said Anaximander, through the evolution of a substance subjected to temperature changes which developed from the eternal, boundless, basic element. A sphere of flame arose from this, as from an explosion, and assumed a rounded form with concentric divisions. As these rings became detached, the sun, moon, stars, and other heavenly bodies and the earth were formed. Aristotle tells us that, according to Anaximander's theory, the terrestrial region was at first moist; and, as the moisture was dried up by the sun, the portion that was evaporated produced the winds and the turnings of the sun and moon, the remaining portion becoming the sea. In time the sea, Anaximander held, would dry up. The heat, or fire, of the world would burn the whole of the cold moist element. Then the world would become a mixture of heat and cold like the boundless, primary element surrounding it, and by which it would be absorbed. This theory of matter and the evolution of the world marks a notable advance over any previous scientific theory. It was well developed by numerous teachers of the Milesian philosophical school and has played a great rôle in intellectual history. The daring nature of some of Anaximander's explanations of earthly organisms may be realized from a sketch of his views on the evolution of animals. He taught that living creatures arose from the moist element as it was evaporated by the sun. Man at first resembled a fish. All animals were developed in the moisture wrapped in a protecting cover or bark. As they advanced in age, they came out into a drier atmosphere and discarded their protective coats. Man was not an original creation, but resulted from the fusion of other species. Anaximander's reason for this statement was that the period of infancy of the human being is so long that had he been born that way originally he could not have survived. There must have been a slow development from ancient ancestors. This may be regarded as an anticipation of the Darwinian theory. Thus man's thoughts in succeeding ages have a rhythmic swing. Anaximenes rejected some of Anaximander's ideas and furnished new ones to take their places. He was not so daring a thinker as his predecessor, and his theory of the world was not as interesting as Anaximander's. Many of his teachings, however, are accepted as sound to-day. Anaximenes contended that the basic element was not boundless, but determinate. Innumerable substances are derivable from it and, just as our soul, like an atmosphere, holds us together, so do breath and air encompass the whole world. Air is always in motion, otherwise so many changes could not be made by it. It differs in various substances in virtue of its rarefaction and condensation. The perpetual changes taking place in the world owing to the instability of matter were emphasized by Heraclitus. He taught that there is nothing immutable in the world process excepting the law or principle which governs it. Cosmological speculations were not the only ones attracting the attention of the Greek scientists. Pythagoras, for example, founded a philosophical college devoted to mathematical studies which resulted in the development of arithmetic to points beyond the requirements of commerce. He made arithmetic the basis of a profound philosophical system. Pythagoras studied science in Egypt and first became familiar with Egyptian and Babylonian mathematics and geometry. He also studied the Milesian cosmological philosophy. On his return to Greece from his foreign studies he sought to discover a principle of homogeneity in the universe more acceptable than any suggested by the earlier philosophers. He had noticed numerous relationships between numbers and natural phenomena, and believed that the true basis of philosophy was to be found in numbers. In seeking data to sustain this thesis, he discovered harmonic progression. His experiments showed that when harp strings of equal length were stretched by weights having the proportion of ½:⅔:¾, they produced harmonic intervals of an octave, a fifth and a fourth apart. Since he saw that harmony of sounds depended upon proportion he concluded that order and beauty in the world originate in numbers. There are seven intervals in a musical scale, and seven planets sweeping the heavens. Seven must, therefore, be a basic number. This suggested to him his ideas regarding the harmony of the spheres. Pythagoras and his students found that the sum of a series of odd numbers from 1 to 2n+1 was always a complete square. When even numbers are added to the above series we get 2, 6, 12, 20, etc., in which every member can be broken into two factors differing from each other by unity. Thus 6 = 2.3, 12 = 3.4, 20 = 4.5, etc. Such numbers were called heteromecic. Numbers like n(n+1)⁄₂ were called triangular. A large number of other arithmetical relations were found and given distinctive names. The Pythagoreans were also familiar with the principles of arithmetical, geometrical, harmonic, and musical proportion. [Illustration: DE WITT CLINTON TRAIN OF 1831 BESIDE A MODERN LOCOMOTIVE] [Illustration: LOCOMOTIVE OF THE 1870 PERIOD STILL IN USE IN THE OZARKS] [Illustration: "JOHN BULL," A LOCOMOTIVE BROUGHT FROM ENGLAND AND PUT INTO SERVICE IN AMERICA IN 1831] Pythagoras made similar advances in geometry. He believed that each arithmetical fact had an analogue in geometry, and each geometrical fact a counterpart in arithmetic. He devised a rule by which integral numbers could be found so that the sum of the squares of two of them equaled the square of the third. He also developed the theory of irrational quantities. The first incommensurable ratio discovered is said to have been that of the side of a square to its diagonal which is 1:√2̅. Euclid (300 B. C.) developed this theory in the tenth book of his geometry as still used. Pythagoras not only placed mathematics on a solid scientific basis, he also established the fact that the physical phenomena of the world are governed by mathematical laws. Little progress appears to have been made in astronomy by the Greeks in the time of Pythagoras. The Milesians and the associates of Pythagoras advanced numerous theories, but none of these was better than some of the Egyptian ideas. Hicetas, and others of this period, believed that the sun, moon, stars, and all other bodies in the heavens were stationary and that only the earth moved. The great turning movement of the earth around its axis produced the illusion that it was the heavenly bodies which were moving while the earth remained stationary. The astronomical theories of Pythagoras, Hicetas, and Philolaus, all affirmed that the universe is composed of the elements earth, air, fire, and water, the whole mass being of spherical shape with the earth at the center and all having life or motion. These early theories, 2,000 years later, did service by aiding to secure acceptance for the Copernican theory. The Pythagorean ideas that the universe is one grand harmonious system, and that thought instead of sense is the sole criterion of truth, have exercised important influence on intellectual speculation throughout the ages. In order to collect data for testing their theories in the physical and mathematical sciences, the Greeks invented many physical appliances. The monochord, employed in determining the relationships of vibrating harmonic strings is one of the first mechanisms used in practical physics that we have definite information about. An anvil, metal and glass disks, and bell-shaped cylinders were employed in studying the movements of sound waves. Alcmæon (508 B. C.) was one of the earliest of the Greek anatomists. He was a disciple of Pythagoras and employed the logical research methods of his teacher in the investigation of medical problems. Although the Egyptians had developed medical science to a considerable extent and had taught the Greeks, their methods were not based upon sound principles. The result was that the more analytically minded Greeks could not accept certain Egyptian ideas. The Egyptian anatomical teachings were particularly crude, and Alcmæon began to investigate that science. His discoveries, both in anatomy and physiology, were very great. He outlined the functions of the principal organs of the body, discovered the optic nerve, the difference between the arterial and nervous systems, the Eustachian tube, the two divisions of the brain, the nerves connecting the brain with the organs of sense and with the spinal column. These advances placed the medical sciences on a logical basis similar to that of the physical, mathematical, and astronomical sciences. This first great anatomist and physiologist invented the practice of anatomical dissection and surgical exploration, and advanced the practice of medicine to a higher degree of usefulness. After the Greeks had satisfied themselves that they possessed a cosmological theory which answered the demands of reason they turned their investigations to the question of how matter was changed into its innumerable forms. Empedocles had taught that when the primary elements, earth, air, fire, and water, were mixed in variable proportions they yielded different kinds of matter. Leucippus, Democritus, Anaxagoras, and others studied the subject more carefully and developed a novel theory. When matter is divided as far as possible do the ratios of the constituents remain the same? This problem attracted their attention. They also asked themselves whether there was not a simpler conception to explain the basic state of matter. When they began their inquiries, the qualities of matter were believed to reflect their essences. For example, the sweetness of honey and the color of the sky were real things which should be studied in themselves apart from honey and the sky. Democritus thought, however, that such changes of color as the sky undergoes at dawn and sunset would not take place if the colors were real elementary things. While meditating on this the thought arose in their mind: "If we assume matter to be composed of an infinite number of minutest particles or atoms, could we not explain the changes in matter by changes in atomic quantities and orders?" This line of thought resulted in the development of the atomic theory and the origin of the philosophic school of the atomists. According to Leucippus some of the atoms darting about in the universe collide and thus give rise to new substances. He also believed that the atoms followed whirling or circular paths and that such rotary motions drew in neighboring atoms, and that as these movements continued indefinitely within the atoms the constituents were being constantly rearranged, the lighter elements being grouped around the periphery; the heavier ones around the center. These changes were due to pressure and impact. These conceptions about atoms were carried into cosmological discussions and it was taught that there are various worlds and planets within the boundless universe, each one moving freely according to physical laws, unless fractured by collision with another. Zeno challenged these doctrines because of the importance attached to the whirling motion. He attempted to show that such atomic motions are impossible. His proofs of the impossibility of atomic motion were designed with the object of sustaining his own theory of an ultimate principle of unity. His mental trend was toward negation. Whenever his rival Parmenides argued affirmatively regarding a scientific principle, Zeno would invariably maintain the negative side of the question. Zeno's first proof of the impossibility of motion referred to the impossibility of passing through a fixed space. He showed that by dividing a line into an infinite number of parts an infinite number of points would be obtained and these permitted no beginning of motion. His second proof tried to show the impossibility of passing through space having movable boundaries. The story of Achilles and the tortoise illustrates this. A pursuer in a race at every interval must reach a point from which the pursued starts simultaneously. But the latter is always in advance. The third, or "resting arrow," argument showed that a moving arrow is at every instant in some one point of its track. Its movement at such instant is then equal to zero. Its track is a group of zeros. No magnitude could be framed from these. Zeno also anticipated much later philosophical discussions, like Einstein's, relating to the relativity of motion. He took for an example a moving wagon. Its movement would appear different to observers on other moving bodies going in various directions. They would see changes in rates of speed as well as in direction. Protagoras, at a subsequent date, developed this idea of relativity and showed that things are as they appear to each individual at the moment they are perceived. He summarized his teaching in the aphorism: Man is the measure of all things. The Skeptics, 200 years later, developed the Protagorean theory of relativity, and by a series of arguments attempted to prove that perceptions change not only with the different species of animate beings, but with many conditions and circumstances. It was also shown that not only man's perceptions are subject to changes, but also his opinions following from his perceptions. Another school taught that to every opinion the opposite can be opposed with equally good reasons. CHAPTER VI GOLDEN AGE OF GREEK SCIENCES Science had made a great advance as a result of the researches and theories of the atomists. A consistent mechanical theory of matter and the universe had been set forth. Science and philosophy were stripped of many of the old superstitions that had clung to them. The leading theories invented were based on logical principles. While these changes were being worked out, numerous inventions of scientific instruments and apparatus were made and systematic methods of studying science were organized. These furnished the means for still greater progress. The apparent completeness of the mechanical theory of the universe satisfied the inquiring intellect. The excitement caused by the scientific discussions and discoveries from the time of Heraclitus subsided. But after a short intervening period, when public attention had been largely centered on practical affairs, there was a reaction against science. When scientific principles were quoted a tendency was shown to question their validity and usefulness. This resulted in inquiries into the sources of knowledge and conduct and ushered in a new intellectual era that is now known as the Humanistic period which, beginning about 450 B. C., extended to 400 B. C. The Sophists, who were teachers of rhetoric and were accustomed to studying the phrasing of verbal statements, became active in searching for the foundations of thought. The Protagorean theory of knowledge was based on Empedocles's doctrine that the inner atoms advance to meet the outer ones. Perception is the resultant product of these atoms when they collide. They believed that this perception is something else than the perceiving subject and is also something different from the object giving birth to the perception. It is conditioned by both, but has a distinct existence. The doctrine of the subjectivity of sense perception was developed in explanation of this psychological problem. From this it followed that knowledge must be strictly personal and could be true only under conditions existing at the instant of perception. These limitations caused Protagoras to advance his theory of relativity, which teaches that man is the measure of all things. Facts are what appear to each individual to be statements of truth. Isocrates, Plato, Aristotle, and Socrates were the leaders of this intellectual movement. Socrates developed the Pythagorean theory of intelligible forms. The specific qualities of the senses belong to the realm of perception. When these are withdrawn from an object of thought there remains only the form or idea. Therefore it is evident that pure, intelligible forms constitute the essences of things. The early scientists, such as Democritus, thought, perhaps, in terms of atom forms. Socrates, Plato, and later teachers looked upon forms as conceptions of similar logical elements. Knowledge, in the view of Democritus, was essentially rationalistic. Plato considered knowledge as having ethical and æsthetic purposes within itself. Each of these types of rationalism stimulated Greek thought and resulted in a strong impulse to philosophical and scientific investigation. They prepared the outlook for Aristotle. Science had been hampered by the confusion raised by the discussions relating to forms. Aristotle realized that proper progress in logic, physics, and ethics, the leading sciences of his time, could not be made unless the essential nature of science were kept in view. He saw that knowledge of the forms of correct thinking can be understood only by keeping in view the object of thought and this requires definite ideas of the general relations of knowledge and its objects. The study of general relationships led to the study of particular or special relations. The connection of general with particular ideas was unfolded, and Aristotle saw that conceiving, understanding, and proving result from the deduction of particular from universal, or general, ideas. Therefore science consists in deriving or deducing facts acquired through perception from their general grounds or phenomena. The logical form of the syllogism naturally suggested itself to Aristotle when engaged with these thoughts and the invention of the syllogism was one of the most brilliant contributions to knowledge made by the Greeks. The logical results of the invention of syllogistic forms suggested a solution of the problem of true reality which Aristotle showed was the essence that unfolds in phenomena themselves. This led to fruitful scientific results. Plato and his contemporaries unified mathematics, formulated the definitions logically, and demonstrated correct methods of criticism and proof. A point was shown to be the boundary of a line; while a line is the boundary of a surface, and a surface the boundary of a solid. This concrete definition of scientific elements progressed through the use of analytic methods, by proceeding from the known to the unknown, and led to the discovery of tests for scientific assumptions and of synthetic proof. None of the earlier philosophers possessed anything like the progressive tools Aristotle placed in the hands of scientists. Their use quickly led to a general review of knowledge and a great increase in the number of sciences. The textbook on geometry compiled by Euclid, still used in many schools, gives us a good picture of the state of scientific methods in his time. Euclid, like Aristotle, Plato, Socrates and others, was a great systematizer. He collected the geometrical proofs of his mathematical predecessors, selected those which were logically correct and simple, and raised on a few axioms, or first principles, a great geometrical system. Archimedes published textbooks on spherical and cylindrical geometry. He proved that the surface of a sphere is equal to four times a great circle. He showed the properties of spherical segments and methods for calculating surface areas and other parts of spherical forms. This great scientist also developed mechanics and physics. He investigated the lever and demonstrated the principle upon which its power is based. He then studied hydrostatics and hydraulics, and discovered the theory of specific gravity and invented methods for determining it. Apollonius began publishing scientific textbooks about forty years after Archimedes. His masterpiece was his textbook on conic sections. The work done by Archimedes on the quadrature of curvilinear figures resulted, centuries later, in the discovery of the infinitesimal calculus, while the theory of conic sections published by Apollonius led to theories for the solution of problems relating to geometrical curves of all degrees. They placed the geometry of measurements and the geometry of forms and positions on strictly scientific bases. Hipparchus applied the new mathematical and geometrical discoveries to astronomy. He found a method for representing the observed motions of the sun, moon, and planets by assumed uniform circular motions. His theory of the sun's motion assumed that the earth was not the center of the sun's orbit. He drew a line through the earth and the real center of the orbit and found where the sun's distance is least and where greatest. He then compiled a large set of solar tables giving the position of the sun among the stars at any time. He next turned his attention to the movements of the moon and prepared tables for determining eclipses. Then the various planets were studied and their mean motions were calculated and recorded. The stars were mapped and catalogued. He described the apparent movements of 1,080 stars and comparing his observations and calculations with those of Aristyllus and Timocharis, made 150 years previously. He also discovered the precession of the equinoxes. The astronomical calculations of Hipparchus led to a great improvement in trigonometrical methods. By using chords, as we use sines, and assuming the heavens to be a plane surface, he fixed the positions of stars (and similarly geographical points) by the intersections of lines of latitude and longitude. A planosphere, an instrument for representing the mechanism of the heavens, was among the many scientific inventions of Hipparchus. While Hipparchus was engaged upon problems in astronomical physics, Hero, a professor of science at Alexandria, was working out numerous problems relating to matter and devising machines for practically applying the teachings of mechanical science. Ctesibius, assisted perhaps by his pupil Hero, made a large number of valuable engineering inventions. He was an authority on hydraulics and pneumatics. He devised improved siphons, a pneumatic organ, a force pump, a vacuum pump, a hot-air motor, and other machines. His studies regarding the physics of gases led him to adopt a molecular theory of matter. He believed that there are vacua existing between the innumerable particles which constitute matter in all its states and forms. Ctesibius improved surveying instruments. His dioptra, an instrument corresponding to a theodolite, was a plane table set on a tripod, furnished with compass points and two sights. The plane was adjusted by screws and a water level. This instrument was used by engineers for leveling, laying out irrigation works and farm lands, sinking shafts for mining and prospecting purposes, and for tunneling. A cyclometer for measuring angles of dip and elevation of rock beds and mountains was also used with this instrument. The Greeks owed much of their knowledge of hydrostatics, mechanics, pneumatics, and physics generally to Ctesibius. He was not only a great inventor and lecturer, but also a writer of valuable textbooks dealing with physical and mechanical sciences. Hero edited a number of editions of the textbooks of Ctesibius, and is credited with inventing some of the theories and machines discussed. He, too, published numerous scientific books. Hero's work in trigonometry was important. He described a formula for estimating the area of a triangle which still bears his name. He defined spherical triangles and arranged methods for determining the volumes of irregular solids by measuring the water displaced by them. The steam turbine is the best known of Hero's machines. Scholars read much about his wonderful musical instruments operated automatically by pneumatic means resembling the mechanisms of player-pianos, and particularly about his mechanical toy mimicking a number of singing birds. A group of birds were made alternately to sing and to whistle. The mechanism consisted of air tubes operating various kinds of whistles. A running stream was made to operate an air compressor. The air from the compressor tank operated the various movements of the birds and supplied air for blowing the whistles. The numerous mechanisms of this character which Hero and his master made indicate that they were as much at home in making pneumatic and similar mechanical toys as is any expert to-day. They not only knew the scientific principles, but had the engineering and mechanical ability to design them and make them work. Hero's fire engine is not as well known as his steam engine. It was a remarkable invention, however. It was worked by levers and force pumps and resembled the engines still employed by fire companies in some remote rural districts. Not the least interesting machine described by Hero was his slot machine for dispensing wine and other liquids. This machine consisted of a cylindrical container with a slot hole on top through which coins were dropped. Beneath this there was a lever with a receptacle for the dropped coin. The weight of a falling coin depressed one arm of the lever and raised the other, which opened a valve and allowed the liquid to escape. When the lever arm had moved a certain distance, the coin slipped off and the valve was automatically closed. Hero's steam turbine was a crude model. Steam was generated in a boiler and conducted through pipes so as to play upon revolving globes or wheel vanes. This machine was invented to operate mechanical toys. It was not until nearly 2,000 years later that it occurred to an inventor that steam could be used to operate more important mechanism than toys. The next great name in science is that of Claudius Ptolemy, an Egyptian astronomer, who lived in Alexandria about 139 A. D. He brought out new editions of the mathematical works of Hipparchus, and published a number of scientific books of his own. His principal work, known as the Grammar of Mathematics, formed the basis of all astronomical studies down to the time of Copernicus, about 1500 A. D. The earth formed the center of the universe, according to Ptolemy's theory. The sun and planets, he thought, revolved around the earth. We obtain our minutes and seconds from Ptolemy's great work. He divided the circle with 360 degrees and its diameter into 120 divisions. Each division of the circumference he divided into sixty parts. The Latin names for these parts were _partes minutæ primæ_ and _secundæ_, or the first small divisions and the second small divisions. The Greek scientists were so interested in logical analysis that they constantly investigated the fundamental facts upon which their teachings were based. They made provisional hypotheses, deduced mathematical consequences, and compared these with the results of observation and experiments. When Hipparchus found that his planetary theories did not meet his tests, he decided to make as many new observations as possible and collect astronomical data to be used at a later period by other scientists. He realized that, while he knew the old theories were incorrect, there was not enough data at hand to enable better theories to be established. He therefore deliberately labored to provide data for posterity. Ptolemy's treatise on geography was an encyclopedia of places, names, and descriptions. In this work he located over 5,000 places between India and Morocco, giving their latitude and longitude. Ptolemy's textbooks on sound and optics were long celebrated. The work on optics contained valuable chapters on refraction, a subject he had done much to develop. These works contained some of the finest collections of experimental data illustrating the best scientific methods used in antiquity. The next great mathematicians and physicists are Pappus and Diophantus. The former lived about 300 A. D. He was the author of textbooks on mathematics and astronomy. Some of these have been preserved and are of great value in exhibiting the status of Greek science at that time. The arithmetical textbook of Diophantus, which is extant, is remarkable as being the first to contain a complete exposition of algebra and the use of algebraic symbols and methods. Euclid solved quadratic equations geometrically and Hero solved them algebraically, although without using symbols. But in Diophantus's arithmetic quadratics are solved by the use of algebraic symbols. After several centuries, when the Euclidean geometry was in the ascendant, and many problems which were suited to arithmetical and algebraic methods of analysis were solved by geometrical and trigonometrical means, Diophantus succeeded in renewing interest in arithmetic and mathematics generally. Political changes and other intellectual interests soon after the time of Diophantus turned men's thoughts in other directions and no great scientists were afterward developed by the Greeks. While the physicists were making their discoveries, medical men were studying anatomy, biology, and materia medica. Medical science in the time of Diophantus had a status, with a theory and practice, closely resembling those of to-day. Hippocrates of Cos (460 B. C.), was the greatest leader of Greek medical science. He cast superstition aside and based his researches and practice upon the same principles of inductive philosophy that had proved so valuable in other sciences. He established hospitals for the nursing of the sick, and had attendants note the symptoms and the histories of the cases. In this way a number of casebooks were made. He wrote a work on Public Health. His operations in trepanning were more heroic than would be undertaken by good surgeons to-day. These are described in his book on Injuries of the Head. Many of his works are extant and furnish very interesting and valuable pictures of the state of medical science in Greece. During the several centuries in which the Greeks placed science and all the leading departments of knowledge upon firm bases, stripped of the sentimental and traditional trappings which had come down from remote times, changes of a political nature were causing the immigration of foreign peoples to Greece. The importance of preserving racial purity was not recognized. The result was that the original Greeks, who were of the long-headed type, were forced to give way to the hordes of inferior peoples coming in from Asia. These new, round-headed people were not original thinkers, and were unable to advance science and the arts as the Greeks had done. They were, to a large extent, even unable to appreciate the wonderful treasures of knowledge bestowed upon them by the cultured people they had displaced. The Egyptians and Babylonians advanced knowledge for practical purposes and when these were served they showed no desire to explore further. But the analytical mind of the Greek called for knowledge of basic laws and first principles. CHAPTER VII THE ROMAN AND MIDDLE AGES The Romans succeeded to Greek culture; but they were a business people. They exhibited smaller intellectual capacity than the Greeks for analytical thinking. This precluded them from advancing the sciences. The Romans attained great eminence in oratory, history, art, and literature. They probably equaled the Greeks in music. They never produced any great thinkers like Aristarchus, Hipparchus, Euclid, Ptolemy, Archimedes, Democritus, Hippocrates, Plato, Aristotle, and others referred to in the preceding chapters. What the Romans lacked in intellect they made up in energy. They became good soldiers and sailors, good politicians, able architects, engineers, and farmers. This explains how they became so powerful politically. They were the most practical people in a practical world. Instead of bequeathing us great scientific masterpieces like the Greeks, they have left us miles of useful roads, waterways, walls, fortresses, bridges, buildings, and statuary. Remains of these objects occur throughout Europe and northern Africa, showing that Roman engineering practice has been as universally useful as Roman law and political practices. The great scientific discoveries of the world have been made by only a few peoples. Those nations which have possessed the scientific temperament have not always been productive. Great inventions and discoveries appear to be made in response to national needs and are preceded by long periods during which the preparatory work is being done. The great men of science being active generalizes, need the cooperation of many lesser scientists to collect data and observations upon which general theories may be built. This appears to be the explanation of the irregular periods of great scientific activity. Julius Cæsar, great in many departments of human endeavor, carried through two important scientific reforms. He caused the rectification of the calendar. In the year 47 B. C. there was an accumulated error of nearly 85 days in the calendar. This was corrected and the year was made to consist of 365 days, with an additional day every four years. Cæsar's calendar is still in use. His other reform, which was not completed until the reign of Augustus, was a scientific survey of the Roman empire. This conferred great benefits not only upon Rome, but upon the world. Geography, commerce, and industry were enlarged, many practical scientists were trained, and the various data and maps which had to be collected and drawn resulted in many improvements in statistical methods and in surveying and astronomical computations. An early contribution to science by Rome was the textbook on Architecture by Vitruvius. This great work became the standard guide to building until the changed conditions in the Middle Ages called for new architectural methods. The works on natural philosophy by Lucretius, the geography of Strabo, the books on natural history by Pliny, and the encyclopedic medical works of Galen were successive contributions. These chiefly aimed at developing the teachings of the great Greek scientists for the practical use of the Romans. Roman history shows that all branches of the learned professions were popular and Roman professional men were very competent. None, however, stands out as a great discoverer. The names just above recorded are those of the chief lights of Roman science, and they simply reflect the practical nature of the Roman intellect. The best the Romans did was to preserve Greek science, test it extensively by practical applications throughout their vast empire, and hand it on to succeeding nations. Philosophical thought in the declining years of Greece turned to theosophical speculations, and finally to ethics and theology. Much interest was evinced by the Romans in ethics, æsthetics, and theology. A new religion, destined to exert profound influences on intellectual developments, gradually attracted the attention of thinkers. The Romans were fascinated by the monotheism of Christianity and the doctrines of a future life and good will and love. There grew out of the critical attacks on this new theology a powerful scholastic philosophy aiming at the exposition, systematization, and demonstration of the principal Christian doctrines. Aurelius Augustinus, a native of Africa (353-430 A. D.), championed the opinion that knowledge of God and self was the proper kind to study. The sciences have only value in illuminating the power of God. Intelligence is necessary to comprehend what we believe; faith is required to believe what we comprehend. As the highest good, or moral ideal, is transcendent, Christians cannot realize it, so human perfection should consist in the love of God and bearing good will to others. The conditions brought about by this turn of thought were not favorable for scientific development. The world had to wait until the scholastic philosophy lost itself in metaphysical discussions. Then Roger Bacon (1214-1294) released science and mathematics from the chains which had so long confined them. While European thought was occupied in discussing scholastic philosophy, the Arabs and Moors were carrying on the practice of the sciences. The Moors in Spain published many valuable textbooks and developed new principles in architecture and medicine. Their Giralda observatory in Seville was the first astronomical building erected in Europe, and their university in Cordova remained for a long period the leading professional school. The universities of Paris, Salerno, Oxford, and Cambridge, and the law school at Bologna, were founded in the eleventh and twelfth centuries and have continued to hold up the torch of science until our time. Roger Bacon, an English Franciscan monk, was a graduate of the University of Paris. He was a brilliant student of physical and mathematical sciences. Pope Clement IV invited him to write a textbook of science. Bacon did this in 1266. He became a professor in Oxford University in 1268. His _Opus Majus_ (1267) summarized ancient and current philosophy and science and included the researches of the Moors. This great book reasserted the fact that science must be based upon experiments and that the astronomical and physical sciences must rest upon geometry and mathematics. Bacon's clear recognition of the value of experimental methods and logical exposition mark him as the greatest intellectual force of his century. The errors in the calendar were estimated and corrected by Bacon. He criticized the astronomical principles of Ptolemy, which were still generally accepted. His experiments in physics led him to make important discoveries in optics. He improved lenses and apparently made microscopes and telescopes. He proposed a lunar theory in accounting for the movements of the tides. Roger Bacon made so many accurate comments on physical phenomena and so accurately forecasted recent mechanical inventions that his book, which was so far in advance of his time that it was unintelligible and caused him to be charged with witchcraft, still astonishes its readers. Lenses were used for spectacles in Asia in the remotest times, but there are reasons for believing that Bacon was the first to prescribe them on scientific principles for the correction of defective vision. He also appears to have appreciated the value of gunpowder as an explosive agent and had it introduced into Europe from Morocco. Being misunderstood, Bacon founded no school and left no students. Nicole Oresme, Bishop of Normandy (1323-1382), used fractional powers in mathematics and developed a notation. About the same period, Thomas Bradwardine, Archbishop of Canterbury, wrote on star polygons, and other Englishmen, like Boethius and Bath, wrote new textbooks on astronomy and mathematics. They started a school of trigonometry in England that made great improvements in that branch of science. Between 1200 and 1400 A. D. the magnetic compass was improved and used at sea, clocks were improved and made popular, improvements were made in weaving, printing was invented, textbooks were written on many subjects, and education began to spread in Europe. All these factors prepared the way for a great industrial and scientific awakening. Nicholas de Cusa (1401-1464), Bishop of Brixen, published books on mathematics and suggested that the earth's movements indicate a diurnal rotation. The way was now paved for a new theory of planetary motions. Nicolaus Copernicus (1473-1543) a Pole, developed the astronomical system bearing his name, as a result of suggestions gained by studying the works of the Greek astronomer Hicetas, and Plutarch's Lives of Greek Scientists. His great work was entitled "De Revolutionibus Orbium Celestium, or the Movements of Heavenly Bodies," which treated the sun as the center of the planetary system. Weather forecasting was improved by Tycho Brahe (1546-1601), and many fine astronomical observations were made by him. He greatly improved astronomical instruments and built and splendidly equipped a great observatory in Uraniborg, Denmark. Numerous important observations were made there. John Kepler, the discoverer of the ellipticity of the planetary orbits and the laws of their movements, was a student under Brahe, and continued his master's researches. His observations on the movements of the planet Mars led to his discovery that the planets travel in ellipses and not in circles. Besides his numerous works on astronomy he wrote valuable books on optics and other scientific subjects. Galileo (1564-1642) took up the work of Tycho Brahe and Kepler and carried it forward to new triumphs. He made the first telescope ever used for astronomical observation, and with it was able to discern that the Milky Way was composed of aggregations of innumerable stars; that the surface of the moon was covered with plains and mountains, that there were four moons revolving around the planet Jupiter, that the planet Venus showed phases like those of the moon as she moved around her orbit, and that there were black spots, at times, upon the sun, which revealed its rotation on its axis. Galileo did equally fundamental work in developing the laws of motion, and the principles of mechanism and physics. The development of modern mathematics began with three intellectual feats--the invention of the Arabic notation, of decimal fractions, and of logarithms. The notation was derived by the Arabs from India about 700 A. D. They had used numerals long before, but the old system was crude like the systems employed by the Egyptians and Greeks. The Textbook on Mathematics by Mohammed ibn Musa, published at Bagdad about 825 A. D., contained the first notable exposition of modern numerals. This important work gave rise to many more Arabic treatises, some of which showed improved methods. Decimal fractions were used by the early peoples of central Asia and were transmitted by them to the Babylonians. Their system was based, apparently, upon a sexagesimal scale. Simon Stevin (1548-1620), a Belgian, made great improvements in decimals. He adopted the plan of William Buckley, of England, and other mathematicians, and made the base 100,000, instead of 60. John Napier (1550-1617), a Scottish nobleman, invented logarithms. The story of this great mathematician's work is one of the most interesting in the history of science. Napier's first table of logarithms was published in 1614. Henry Briggs (1556-1631), professor at Oxford, made suggestions for the improvement of the tables, and persuaded Napier to make the base 10, as is now done in tables of common logarithms. Briggs published tables in 1624 containing the logarithms to 14 places of decimals for the numbers between 1 and 20,000 and from 90,000 to 100,000. Adrian Vlacq (1600-1667), a Dutchman, computed the logarithms of the numbers running from 20,000 to 90,000, and thus completed the whole series of logarithms between 1 and 100,000. Edmund Gunter (1581-1626), of London, calculated the logarithmic sines and tangents of angles for every minute to seven places. He invented the terms cosine and cotangent and used them in a work published in 1620. Another Englishman, William Oughtred (1574-1660), wrote textbooks on mathematics, and invented numerous mathematical symbols which are now in general use, as well as rectilinear and circular slide rules. Bonaventura Cavalieri (1598-1647) made many improvements in mathematical formulæ and expounded a new method of indivisibles which solved some of the difficult astronomical problems raised by Kepler, and enabled Torricelli, Viviani, de Roberval, and others to solve abstruse problems relating to all types of curved figures. Pierre de Fermat (1601-1665), one of the greatest of French mathematicians, developed rules for calculating maxima and minima. His functions in this type of equation closely approached those of the differential calculus. The calculus was developed from Fermat's work by Lagrange, Laplace, Fourier, and other Frenchmen. Pascal and Fermat developed the theory of probability. Pascal worked out many useful methods for dealing with curves. The intense mathematical activity in England and France resulting from the stimulation given by the invention of Napier, prepared the way for the discovery of the infinitesimal calculus by Newton and Leibnitz. Newton was born in England the same year that Galileo died in Italy. His greatest work is presented in his celebrated "Principia," or "Mathematical Principles of Natural Philosophy," in which the law of gravitation, the laws of motion, and the mathematical principles of mechanics are developed. The "Principia" was published in 1687, and it has ever since been regarded as the corner stone of mathematical and physical science. CHAPTER VIII SCIENCE IN THE SEVENTEENTH CENTURY The wonderful advances made in the mathematical, physical, and astronomical sciences, and the invention of many new scientific instruments, together with the publication of improved textbooks and scientific tables, like those mentioned in the preceding chapter, stimulated interest in other fields of science at the beginning of the seventeenth century. Medicine, which failed to advance with the astronomical and physical sciences, began to improve. The Moors had established great medical schools in Spain, but their teachings were based upon the principles enunciated by Hippocrates and the Greek schools. Modern medicine was started upon a firm basis by John Harvey (1578-1657). Hippocrates taught that the blood was one of the principal parts of the body--one of the four great "humors." Its movements, however, had never been investigated until Harvey began to study the functions of the arterial system by the dissection of animals. The arteries had been considered as merely air tubes. This was due to the fact that they were studied only in post-mortem examinations when they were empty. The anatomists of the sixteenth century failed to grasp their importance. Harvey, who was a penetrating observer, had studied in several continental universities as well as in England, and having an original mind he determined to test the medical theories which he had been taught. His discoveries of the functions of the heart, the arteries, and the veins were epochal. He did his work so well and made such simple, yet telling, demonstrations that he had less difficulty than his predecessors in getting his teachings accepted. He was soon recognized as the peer of Hippocrates and Galen. Harvey died without actually seeing the blood coursing from the arteries into the veins, but four years after his death Marcello Malpighi (1628-1694) exhibited microscopically the passage of blood corpuscles through the minute vessels in the lung of a turtle, on their way from the heart through the arteries into the veins and returning to the heart. The blood circulation was demonstrated at a subsequent date by applying a microscope to the web of a frog's foot. With low-powered lenses a good view is obtainable in this manner. Many other important discoveries were made by Harvey, particularly in embryology. He demonstrated that the embryo chicken is formed by gradual development and processes of differentiation and not, as had previously been believed, from a minute perfect chicken. Microbes were discovered in 1683 by Antonius von Leeuwenhoek (1632-1723), when he was examining some scrapings from his teeth. He saw for the first time the long and short rods of bacilli and bacteria, the spirillum and the micrococci. He tried means for destroying them and met with a fair degree of success with a gargle composed of a mixture of vinegar and hot coffee. This experiment was one of the early anticipations of antiseptic surgery, which was invented by Lister in the nineteenth century. A French surgeon, Ambroise Paré (1517-1590) was a pioneer in the treatment of wounds. The old method was to use boiling oil. He found that by simply cleaning and bandaging wounds he could get better and quicker results than with hot oil, which was a very painful treatment. Paré used ligaments in stopping hemorrhages, improved the surgery in harelip and hernia operations and for suprapubic lithotomy. He learned the principles of these operations from Peter Franco (1505-1570), an itinerant surgeon, who had much skill in operations for kidney and bladder troubles. Franz de la Boë (1614-1672), a professor in the university of Leyden, who is best known under the name of Sylvius, the discoverer of the brain fissure of Sylvius, founded a new school of chemical medicine. Van Helmont suggested to him the possibility of the stomach being the seat of many common disorders. When this was investigated, many experiments were made with new medicines. The success of these experiments led to a great reform in medical practice. Thomas Willis (1622-1675), an English physician, completed the development of the treatments suggested by Van Helmont and Sylvius as a result of their studies of the works of Harvey. Another great English medical genius arose to establish the practice of medicine on a scientific basis. Thomas Sydenham (1624-1689) founded a school of medicine in accordance with these three principles: (1) Accurate descriptions of the courses of diseases, (2) following a fixed method of treatment in each disease, (3) searching for specific remedies for each diseased condition. The results of these teachings were very pronounced. Before Sydenham's time, the only drug used in medicine was an extract of cinchona. The Dutchmen above named and Sydenham discovered many active medicinal substances. Sydenham's principal discovery in materia medica was that of the properties of laudanum. William Gilbert, court physician to Queen Elizabeth of England, while Galileo and Stevin were developing the laws of gravitation and hydrodynamics, undertook the investigation of the laws of terrestrial magnetism and chemistry. His researches in chemistry were extensive and valuable. His fame, however, was perpetuated by his study of magnetism and electricity. He found that the earth is a vast magnet with north and south poles. His remarkable textbook on magnetism covered many of the fundamental facts known to-day. He noted the distinction between magnetism and electricity, described electrical charges, the principles of conductivity and methods for magnetizing iron. Galileo wrote of him: "I extremely admire and envy this author." The mercurial barometer and its laws were discovered by Evangelista Torricelli (1608-1647) a student of Galileo. By means of his barometer, Torricelli was able to make great advances in knowledge relating to the physics of the air and to gas pressures, and he investigated the principles of hydraulics. The microscope, telescope, sextant and other instruments were greatly improved by him, and his mathematical work ranks only second to his contributions to experimental science. The Torricellian tube, used as a barometer, was a means of creating a vacuum, which was formed at the top of the column of mercury. Pascal, the French mathematician, took up the study of the physics of the vacuum and published an important work on his own experiments. These and other experiments made by European scientists prepared the ground for, and suggested, the investigations of gases and vacua by Boyle, Mariotte, and others which finally resulted in the invention of the steam engine and many other modern machines. Robert Boyle (1627-1691) published at Oxford in 1660 a book which distinguished between chemical compounds and chemical mixtures. He adopted the use of the term gas, which was first proposed by Van Helmont, and made some valuable studies on the physics of boiling and freezing. The oxidation of metals, the results of calcination, and of the fusing of metals and alloys, calculation of the atmospheric pressure, a study of colors as affected by light rays, and investigations in electricity were among the scientific works carried out by this great experimenter. But his fame rests mainly upon the results of his researches on gases. Boyle began life as an alchemist and died a well-trained chemist. Edme Mariotte, a French contemporary of Boyle's, carried out similar experiments and assisted in formulating the physical laws of gases bearing the names of Boyle and Mariotte. A German physicist, Otto von Guericke (1602-1686), also followed up Boyle's work and invented a new form of air pump. He also carried on important experiments in electricity. Gilbert, Harvey, Van Helmont, Torricelli, Boyle, Mariotte, and other similar pioneers in scientific methods not only invented numerous valuable instruments and wrote suggestive textbooks, but advanced scientific learning and the love of it by their delightful accounts of their experiments. Modern education started with these men. Before this period there had been a sterile age in which the fundamental purpose of education was only to teach men how to protect the soul and to serve God. This humanistic principle, however, failed to advance knowledge of the laws of nature, and the researches of the scientists gradually caused a strong reaction against it. This in turn resulted in further advances being made, not only in the sciences, but in all departments of learning. The way was paved for the era of naturalism, developed by Hobbes, Locke, Descartes, Voltaire, Kant, Rousseau, and others. Naturalism aimed at explaining all phenomena in the simplest terms, and correlating all things by universal principles. It has received a great impetus in modern times from the Darwinian theory of evolution. The great scientific discoveries of the sixteenth and seventeenth centuries had other important educational effects. They led to professional specialization and the founding of scientific institutions, schools, and universities. The Lyncean Society of Scientists was founded in Italy in Galileo's time. It subsequently became, in 1657, the Accademia del Cimento. The Royal Society of England was organized about 1645 and chartered in 1662. It did much valuable scientific work from its inception. It has assisted the foremost scientists in their work, directed scientific researches, and financed the printing of scientific records and the carrying out of foreign expeditions. Nearly all the leading countries in the world have formed institutions with similar aims. The chemical discoveries of Boyle attracted widespread attention and led to investigations started with the view of discovering the constitution of matter. Hermann Boerhaave (1668-1738) of Leyden, took up the study of organic chemistry. Stephen Hales (1677-1761) did similar work in England. Both of these chemists invented valuable laboratory processes and instruments. Hales improved the pneumatic trough used for collecting gases. Scientists were now furnished with the telescope, compass, sextant, microscope, barometer, thermometer, air pump, manometer, and other instruments so that cellular structures of plants, animals, and insects, the microbes and bacteria, the animalculæ found in water and in the sea, as well as the phenomena of the air, sky, and earth crust could now be studied by trained observers. The invention of these instruments caused workers to specialize more and more, and completely severed science from philosophy, of which it had been an appendage since the earliest times. The microscopical investigations of Malpighi, Kircher, Leeuwenhoek, Grew, and Hooke opened up an immense field for research. They developed microscopical chemistry and anatomy, and changed the prevailing ideas regarding animal and vegetable tissues. The sciences of mineralogy, botany and entomology were benefited and the medical sciences were practically revolutionized. The first publications of the Royal Society show the widespread attention microscopical and telescopic studies were then receiving. [Illustration: Copyright, Keystone View Co. WEATHER AND ASTRONOMICAL INSTRUMENTS ON THE ROOF OF GREENWICH OBSERVATORY, ENGLAND] [Illustration: Courtesy "Aeronautics," London A MOORING TOWER FOR AIRSHIPS, WITH THE R-24 FASTENED HEAD ON] Francis Bacon (1561-1626), René Descartes (1596-1650) and Gottfried Leibnitz (1646-1716), in England, France, and Germany, respectively, lent powerful aid to the advance of science at this time. Bacon's great learning enabled him effectively to describe scientific methods and to direct scientific criticism. He attracted general attention to scientific methods based on inductive processes. Descartes, seeing that the world's best intellects had long been exercised with philosophy and metaphysics, without discovering anything with certainty, resolved to accept no beliefs upon the authority of any name or reputation. He would reach his own conclusions based upon the scrupulous examination of data. He hoped to solve the mysteries of nature by the aid of mathematics and geometry, and developed the Cartesian philosophy. The mathematical works of Descartes are now better known than his general scientific ideas. He published in 1637 his "Discourses on Method" and on Geometry. In the last-named work, suggestions are given for the development of analytic methods. It has been said of his formulæ that they are even cleverer than himself. The general use of his analytic methods by other mathematicians resulted in the solution of many scientific problems that had been handed down for centuries as insoluble. Descartes also advanced algebra. The application of the doctrine of curved lines to algebra greatly enlarged the scope of its usefulness. In making these innovations, Descartes introduced the methods and symbols of modern exponential notation. The English mathematician Wallis was also an important agent in the development of mathematical notation. He based his work on the Greek notation and that of Nicolas Chuquet (1484), J. Bürgi, Thomas Harriot (1631), Johann Hudde (1659), and others. Descartes was familiar with the writings of these scholars and, undoubtedly, was influenced by them. Roberval, Fermat, and Pascal were contemporary mathematicians in France and left great names in the history of the mathematical sciences. They all made contributions which permanently enriched mathematics and made further progress in other sciences possible. The geographical sciences now began to attract attention. The new scientific instruments made it possible to collect data in all parts of the world that was needed in unraveling scientific mysteries. William Dampier (1653-1715) was one of the pioneers in scientific voyages of discovery. In voyages to the Orient and Australasia he collected much important data on zoölogy, botany, meteorology, the winds, tides, currents, and on fish and sea life. His book on winds became the first great standard work on meteorology. The doctrine of spontaneous generation had long held sway in Europe. The Greeks entertained it and it was accepted as true in the time of Martin Luther. Francesco Redi (1626-1697), an Italian biologist, showed that when the flesh of dead animals is protected it remains fresh. The Abbé Spallanzani (1729-1799) carried Redi's theory further and showed that microbes and bacteria do not develop in concoctions which have been boiled and sealed. Here we note the beginning of antiseptic science. Under the leadership of Bacon in England, Calvin in France, Luther in Germany, and Knox in Scotland, European thought was being stirred up while the great discoveries just related were being made. Just as Boyle's chemical discoveries caused the divorcing of chemistry from alchemy, and the naturalistic philosophy of the times led to the specialization of scientists and the breaking off of philosophy from science, so the intellectual awakening aroused by Bacon and his contemporaries led to the suppression of belief in witchcraft and to revolutionary ideas in religion and ethics. Locke endeavored to base a "rational Christianity" on the ground of experience. Until his times, theology was tangled up with a maze of physical problems which dismayed even such intellects as those of Newton, Hume, and Locke. Newton's researches were chiefly based upon mathematical and astronomical problems. While a student at Cambridge in 1660, he studied the works of Descartes, Kepler, Van Schooten, Barrow, and particularly those of the Greek and British mathematicians. The works of J. Wallis were very valuable to him. The "Arithmetic of Affinities" of Wallis drew his attention to astronomical problems and thus led to his great triumphs later on. Newton's "Principia" has already been referred to as being one of the greatest works of the intellect ever produced. The result of Newton's meditation upon the nature of the central force that keeps the planets in their courses was that he furnished a mathematical basis for Kepler's laws by proving that if the planets describe elliptical orbits about the sun, the force acting toward the sun, keeping them in revolution, must vary inversely as the square of the distance. On the revolution of the moon around the earth he found a practical confirmation of this law of gravitational attraction. He then took up the study of motion in general and showed that every particle of matter attracts every other particle in accordance with the same principle of inverse squares. Botanical gardens were established in Padua in 1545, and not long after in Pisa, Leyden, Paris, and London. Much attention was devoted to medicinal plants, and numerous herbal books were published. Malpighi, Grew, and Camerarius (1665-1721) published works on botany and plant morphology. Ray and Linnæus (1707-1778) studied the classification of plants and compiled textbooks of descriptive botany. Buffon (1707-1788) published his famous "Natural History of Animals" which did for zoölogy what the works of Linnæus did for botany. Looking backward, we can now see that all scientific knowledge has been gained by the trial and error method and cumulative analyses of a multitude of observations. Progress is not made uniformly but in a recurrent, cyclic manner. Reactions follow advances, but in the end all goes forward. CHAPTER IX PRELUDE TO MODERN SCIENCE--THE EIGHTEENTH CENTURY When the eighteenth century opened science had begun to make men think, and the works of the great scientists had changed the trend of thought on all sides. Liberty of conscience, of worship, and of opportunity were demanded, as well as representative government, economic freedom, and individual equality before the law. Men wanted to be free agents. The philosophical writings of Berkeley, Locke, Hume, Spinoza, Voltaire, Rousseau, and others supplemented the books of the scientists and promoted rational thinking. Syllogistic reasoning displaced the practice of accepting beliefs upon authority. This change in public thought reacted most favorably upon science. Gottfried Wilhelm Leibnitz (1646-1716) conceived matter as a plurality of simple forces. Many kinds of matter, he said, exist. There is no single natural force, but an infinite number. Each force is represented by some individual substance. Force is indivisible, immaterial, and unextended. Simple forces he called essential forms, units, atoms, or monads. The monads are not mathematical points, nor physical points. Real points are metaphysical. In other words, Leibnitz created a philosophy of eternal force atoms. The Greeks were taught by Leucippus, Empedocles and Anaxagoras that matter is formed of atoms. Space is infinite; atoms are indivisible. Atoms are in a continuous state of activity. Atoms constitute worlds and planets. Falling through space they give rise to eddying motions by mutual impact. Many philosophers rejected these views. Throughout the ages, however, they were learned by students and when Leibnitz advanced his new atomic theory, the world was ready to consider it. The Leibnitzian monads were like Plato's ideas--eternal purposes. Aristotle held that monads are absolute, indivisible beings. Leibnitz suggested that each monad is in process of evolution and realizes its nature through inner necessity. It is not determined from without. Each form of matter existed in germ in an embryo. Nothing in a monad can be lost, and future stages are predetermined in the earlier stages. Each monad is charged with the past and big with the future. The biologists at this period generally accepted this incasement theory. Caspar F. Wolff suggested, in 1759, that there is an epigenesis or a progressive evolution and differentiation of organs from a homogeneous primitive germ. This view did not meet with approval until Darwin published his great discoveries in the middle of the last century. The history of the atomic theories furnishes a clear illustration of the long period of preparation that great scientific ideas must pass through before they are united by a generalizing genius of exceptional capacity and launched in the form of a new theory. Modern mathematical science grew out of the analytical geometry of Descartes. He showed that the true method for the discovery of scientific facts was to accept nothing as true which was clearly not recognizable as true. All assumptions should be proved. Each difficulty should be separately studied. No intermediate steps should be skipped, and details should be methodically enumerated. Thoughts must be guided in an orderly manner, beginning with the simplest characteristics of an object and proceeding in a logical sequence to the most complicated aspects of each subject. Descartes carried out his own rules in his work. His improvements in the differential calculus, and those in the integral calculus made by Cavalieri, and in the calculus of probabilities by Pascal and Fermat, furnished scientists with instruments capable of solving almost every physical problem met with in their investigations. One of the first results of the new analytical methods was the establishment of the science of optics. Newton demonstrated that white light is composed of rays of various colors, and that the color reflected by any object is due to the ability of the object to reflect certain rays while absorbing the rest. The Dutch physicist, Huygens, championed the undulatory or wave theory of light. Refraction was explained by both Newton and Huygens, and the latter, while studying the double refraction of crystals of Iceland spar, discovered the phenomena of polarization. Boyle's chemical discoveries led to much research in chemistry. Black, Bergman and Van Helmont investigated the properties of carbonic acid gas. Joseph Black treated limestone with acid and collected the gas evolved in a Hales pneumatic trough. He weighed the gas and the remainder of the limestone, finding that what the limestone lost was equivalent to the weight of the gas. He then reversed the process and succeeded in making chalk from a solution of lime. This simple experiment paved the way for chemical analysis and syntheses which have added profoundly to our knowledge of the composition of matter. Bergman tested Black's gas with litmus and found it gave an acid reaction and in 1779 Lavoisier demonstrated that it consisted of carbon and oxygen. Priestley and Cavendish, both English chemists, then took up this study. Cavendish treated iron, tin, zinc, and other metals with sulphuric acid and discovered a new gas which he termed hydrogen. Rutherford discovered nitrogen in 1772 and Priestley isolated nitric oxide, and in 1774 discovered oxygen. In the course of his experiment Priestley also discovered ammonia, sulphur dioxide and other chemicals. His greatest achievements, however, were the isolation and recognition of oxygen, and the discovery of the composition of water. Following up these discoveries, he noted that the air is not a simple elementary substance, but a mixture of nitrogen and oxygen with several impure gases. The work of this great chemist became as fruitful in the chemical field as that of Newton in physics, astronomy, and mathematics. Carl Wilhelm Scheele, a Swede, carried out many experiments which resulted in the discovery of tartaric acid, the decomposition of silver chloride by light, magnesium nitrate, magnesia, microcosmic salt, and sulphureted hydrogen, chlorine, hydrofluoric, and other inorganic acids. He also discovered the following organic acids: lactic, gallic, pyrogallic, oxalic, citric, malic, mucic and uric. He isolated glycerin and sugar of milk and determined the nature of hydrocyanic acid, borax, plumbago, Prussian blue, and other chemicals. He invented many new chemical and laboratory processes. Scheele was an apothecary's assistant and lived in poverty. But although his experiments were conducted under disadvantageous circumstances his discoveries ranked him as the greatest chemist of his time and one of the greatest chemical experimenters of all time. Cavendish established the proportions of the constituents of air, demonstrated the nature of water and its volumetric composition. The character of the experiments conducted by Cavendish, his elegant methods of weighing, measuring and calculating have caused him to be looked upon as the founder of systematic chemistry. He was more scientific in his methods than the brilliant Lavoisier, and much more learned and philosophical than the practical Scheele. While the chemists were making these great advances there were important developments in physical science. Benjamin Franklin (1706-1790), the first American scientist to acquire world-wide fame, announced that lightning was an electrical phenomenon. In 1752 he showed by his famous kite experiments that atmospheric and machine-generated electric charges are of a like nature. Franklin suggested to Cavendish certain electrical experiments with a view to studying the electric force between two charges. These experiments led Cavendish to the discovery of the law of electric attraction between charged bodies. Franklin subsequently discovered the law of conservation of an electric charge. Charles Augustin Coulomb (1736-1806) rendered great service to electrical experimentation. He resurveyed the experiments of Cavendish, Priestley, and other pioneer electricians, and established a theory of molecular magnetization which provided a working formula to explain electrical currents and magnetic fields. Simeon Denis Poisson (1781-1840) discovered the law of induced magnetism which bears his name. Luigi Galvani (1737-1798) observed that the limbs of a frog are convulsed whenever they are connected up through the nerves and muscles with a metallic arc formed from more than one metal. He thought the convulsions were due to a peculiar fluid which he called galvanism, or animal electricity. Another Italian, Alessandro Volta (1745-1827) discovered and explained the theory of the voltaic pile. Nicholson and Carlisle discovered frictional electricity while William Cruickshank showed that a voltaic current decomposes solutions of metallic salts. William Hyde Wollaston used Cruickshank's discovery to prove that frictional and voltaic electric currents are identical. Humphry Davy (1778-1829) in 1807 established a new voltaic theory which combined the chemical and contact theories previously held, and showed that electrical and chemical attractions are produced by similar causes. Chemical affinity he found to be an essentially electrical phenomenon. Francis Hawksbee, in 1705, communicated to the Royal Society a monograph which showed that when common air is passed over mercury in a well-exhausted receiver an electric light is produced. This was the first demonstration of the availability of electricity for the production of light. Dufay (1699-1739) described positive and negative electric currents. Watson determined, for the Royal Society, the velocity of an electric current and found it practically instantaneous. These, and numerous lesser, discoveries did for electricity what the chemical discoveries of Priestley, Cavendish, Scheele, Boyle, Lavoisier, and others had done for chemistry. The numerous voyages of discovery in the eighteenth century helped to develop the geographical sciences. Special expeditions were fitted out for the acquirement of geographical knowledge without any thought of trading profits. The Jesuits carried out a valuable survey of China and Mongolia early in the century. A Danish scientific expedition studied Arabia, the results of which were published by Niebuhr in 1772. James Bruce visited Abyssinia with the view of solving the ancient problem of the source of the Nile. Mungo Park studied the course of the Niger. Captain James Cook led a scientific expedition to Tahiti with the object of making astronomical observations. This resulted in one of the greatest and most valuable voyages of discovery in history. Cook determined the westernmost point of America in 1778 and his accounts of Bering Sea and Alaska revived interest in the Polar seas, which resulted in numerous Arctic and Antarctic expeditions yielding rich scientific returns. The Hudson's Bay Company sent out many investigators to determine the characteristics and resources of Arctic America. The Russians did the same for their own northern lands. These activities of geographical investigators led to improved methods of navigation, nautical surveying, sounding and shipbuilding, besides supplying an enormous amount of scientific data. The British naval authorities pointed out to King Charles II the need for correct nautical tables. Flamsteed, one of the leading astronomers of the day, was appointed Astronomer Royal in 1675, with the definite object of producing a new catalogue of star positions, tide tables, and other nautical data. He immediately founded the Greenwich observatory, which has supplied the world with data for the navigator. Bradley, a successor of Flamsteed at Greenwich, made many important astronomical discoveries while carrying on the star maps. He discovered the aberration of light and the mutation of the earth's axis. Locaille studied the parallax of the sun and made numerous stellar observations at the Cape of Good Hope in 1751. He located the positions of 10,000 stars in the southern hemisphere. Measurements were made in Peru, Lapland, and elsewhere to discover data regarding the earth's curvature. Pendulum observations to detect variations of gravity were made in many countries. Maskelyne, the astronomer royal, made observations on the transit of Venus at St. Helena in 1761. On this expedition he perfected the method of finding longitude at sea by lunar distances. Sir William Herschel discovered the planet Uranus in 1781, and subsequently found its satellites. Many star groups, double stars and nebulæ were discovered by him and he found that the solar system is traveling through space in the direction of a point in or near the constellation of Hercules. Greenwich observatory was publishing at the end of the eighteenth century the Nautical Almanac, and annual reports on star and meteorological observations as well as important astronomical monographs. Similar publications were founded in the next century in France, Germany, and Italy. The discoveries in mathematics during the eighteenth century included the differential, integral, and other forms of the calculus, differential equations, and various formulæ for dynamics, mechanics, and physical and astronomical calculations. Euler, Lagrange, Laplace, D'Alembert, and Carnot were prominent mathematical investigators. Heat in earlier times had been regarded as an imponderable substance called caloric which was supposed to be emitted by hot and absorbed by cold bodies. Thus the expansion of mercury was explained by the addition of caloric and not by the increase of distance between the molecules. Francis Bacon and the Scotch chemist Black did the preliminary work which enabled Count Rumford finally to establish the true theory of heat. Watt and Newcomen were attracted by these studies and reduced their theories to practice in the steam engine. Black described specific and latent heat and invented, and used, the calorimeter bearing his name. Hall invented an achromatic lens for telescopes in 1733, and Dollond, another English optician, improved achromatic lenses and made, in 1758, achromatic telescope objectives. The lenses were primarily designed for astronomical telescopes, but they were also applied to microscopes and other scientific instruments, resulting in improvements in our knowledge of light. The voyages of discovery, in this century, encouraged study of zoölogy and natural history subjects generally, including mineralogy and geology. Hooke, Ray, and Woodward made collections of rocks and fossils in England and advanced hypotheses to explain their origins. Lazzaro Moro suggested that fossils must have been deposited in rocks when they were being formed. He also distinguished rock formations by the characteristic fossils found in them. Hutton and Smith then made scientific studies of English rocks, fossils, and earth sculpture, and prepared the materials for the subsequent brilliant discoveries of Lyell. The first governmental school of mines was established in Freiberg, Saxony, in 1775. This institution, and others which were afterward established in different countries, led to an intensive study of the geological and metallurgical sciences, which eventuated in great advances during the nineteenth century. Aristotle and Theophrastus in early times, Gesner in the sixteenth century, Ray, Grew, Malpighi and Willughby in the seventeenth century, had been the writers of the principal textbooks on zoölogy. Buffon (1707-1785) and Linnæus (1707-1778) were the founders of modern natural history in the eighteenth century. Buffon described species, while Linnæus classified them. Linnæus named _Homo sapiens_ as a distinct species in the order of primates which includes apes, lemurs, and bats, and fixed man's place in nature. The medical sciences were revolutionized by the researches of Edward Jenner. He applied the scientific methods of the chemists, mathematicians, and astronomers to medicine and through accurate observation, skillful experimentation, careful generalization, and thorough verification, founded preventive medicine. His discovery of vaccination as a preventive for smallpox, communicated to the Royal Society in a very interesting paper in 1798, was the pioneer of the many brilliant advances of our day. The Freiberg School of Mines, the Woolwich Observatory, the School of Civil Engineering in Paris (1747), the Universities of Göttingen (1737), Bonn (1777), Brussels (1781), Yale (1701) and Princeton (1746) were founded in this century. Modern industrialism began in the final part of this century. The invention of the steam engine by Watt resulted in giving the greatest impulse to material civilization the world ever experienced. This invention was the direct result of the experimental work of Boyle, Newton, Black, Cavendish, Davy, Priestley, and Lavoisier. It illustrates how the scientific discoveries of one generation furnish the data for the advancement of knowledge by the next generation and how a single invention may change the whole aspect of life, giving employment for vast numbers of people, developing settlement in foreign lands, starting new industries, and extending the fields of commerce. The history of the development of the steam engine from the results of a few basic physical researches by British scientists forms one of the grandest stories in the history of science. The new aspect assumed by the world as a result of the great scientific discoveries and the increases in industry and commerce which followed them seemed strange to the people who were unused to rapid progress. There was a disturbed feeling akin to fear abroad while the new ideas were being popularized and disseminated throughout the world. The movement in favor of enlightenment was strongest in France because of the social, political, and religious oppression of the people. It ended in the French Revolution, which strengthened the respect for reason and human rights throughout the world. CHAPTER X PHYSICAL SCIENCES IN THE NINETEENTH CENTURY During the nineteenth century, the path of scientific discovery might almost be represented by a vertical line. Never before was such rapid and marvelous progress made. The releasing of the mind from the oppressive restrictions of earlier conservative ages liberated the intellectual energies of mankind. A new idealistic philosophy supplanted that of an earlier period and universal attention was given to science and material things. Amidst these changes social science was devolved, and, with it, the study of psychology. But it was the physical sciences which most felt the stimulus of the new rationalistic spirit. The relationships between physical magnitudes are established by measurements. When these are accurately ascertained, questions regarding their variable functions can be solved by mathematical principles. Physics is thus linked with mathematics through measurements. The more science advances, the greater is the accuracy needed in physical measurements. The strictness and clearness of experimentation which has been attained in physics has given birth to a science of measurement, which has its own instruments, rules, methods, and formulæ. Measurement of length is one of the bases of physics. It is a relative operation carried out by comparing the length of one body with that of another. Standards of length are preserved by a Bureau of Weights and Measures in most countries. Delambre, a French authority on the decimal system of measures, taught at the beginning of the nineteenth century that magnitudes as small as the hundredth of a millimeter are incapable of observation. The International Bureau of Weights and Measures now guarantees to determine two or three ten-thousandths of a millimeter. So much has the science of measurement progressed in a century. The undulations of light rays are used for determining standard lengths. Michelson and Benoit measured a standard length of ten centimeters, in 1894, in terms of the wave lengths of the red, green, and blue radiations of cadmium, and then in terms of the French standard meter. These experiments yielded very accurate results. The measurement of mass is another important base of physics. Mass is the quantity of matter in a body and the action which gravity exerts on mass is called weight. Weight does not depend entirely upon mass, but also upon the position of the body weighed, because when the body is weighed in one place and reweighed in another, there will be a difference in the force of gravity due to change of latitude and of altitude. National standards of mass have been made of alloys of iridium and platinum. Many remarkable measurements of time, temperature, and physical constants were carried out during the century. High and low temperature charts were completed, showing temperatures in the air, the earth, and the sea. Instruments and methods were devised for measuring any temperature whether of high furnace gases or low freezing mixtures. The measuring units of mass, length, time, and temperature are fundamental, others like velocity, acceleration, power, and area are referred to them. For that reason the latter are called derived units. Many of these are important and call for accurate determinations. One of the first achievements of the century was the establishment of the doctrine of the conservation of energy. Francis Bacon had suggested that motion is a phenomenon of heat, and Newton had divined the principle of the conservation of energy, but it was Benjamin Thompson, Count Rumford, who discovered the nature of friction and made the first estimate of the mechanical equivalent of heat. Sir Humphry Davy showed that two pieces of ice could be melted by simply rubbing them together, in a vacuum. But he failed to draw the great inference that this experiment warranted. If he had observed that the heat could not have been supplied by the ice because ice is an absorber of heat, he would have anticipated the great work done by James P. Joule, an English physicist, who published the results of many experiments carried out by him prior to 1843. His task was to find the exact mechanical equivalent of heat. His best results were secured by dropping a mass of lead from a measured height and using the energy generated during the descent to operate a revolving paddle in a dish of measured water. Delicate thermometers recorded the increase of temperature in the water and showed that the descent of 424 grams of lead through a distance of one meter, or one gram of lead through 424 meters, generated sufficient heat to raise one gram of water one degree centigrade (1° C.). Otherwise expressed, a fall of 772 lbs. of lead through a distance of 1 foot, or 1 lb. of lead through 772 feet, raises the temperature of 1 lb. of water one degree Fahrenheit (1° F.). These 772 foot-pounds, or 424 gram-meters, represent the mechanical equivalent of heat upon which so many important theories have been based. But Joule's equivalent was determined for common air temperatures whereas the specific heat of water increases with the temperature so that the value of the equivalent rises with increased temperatures. Osborne Reynolds, in 1897, found the mean equivalent for temperatures between the freezing and boiling points to be 777 foot-pounds. The discovery of Joule's equivalent established a relationship between motion or mechanical work performed and the amount of heat generated when work is completely expanded in friction. The same relationships continue good when the work is transformed by indirect means as by generating electric currents or expanding gases. The multitude of elegant experiments used to confirm the truth of Joule's law showed that heat is not a substance, or calorie, but a purely mechanical effect. This great discovery of the relation of friction and heat lies at the basis of electricity, molecular physics, and chemistry, and is the source of the formulæ used by engineers in designing power machinery. The internal combustion engine is largely a result of the discovery of Joule's equivalent and the physical theories derived from it. This great discovery caused a new theory of matter to be developed. Dalton had suggested, when applying the atomic theory to chemistry, that when two elements combine to form a third substance, it is probable that one atom of one element joins itself to one atom of the other, unless some exceptional condition exists. When water is formed by bringing oxygen and hydrogen together, he supposed that one atom of oxygen combined with one atom of hydrogen. Gay-Lussac subsequently proved that not only does one volume of oxygen combine with two volumes of hydrogen (not one as Dalton believed) in the production of water, but that nitric and carbonic acid gases combine with ammonia gas in the ratio of 1:1 or 1:2. He also demonstrated that one volume of nitrogen united with three of hydrogen form ammonia, and that carbonic oxide burning in a mass of oxygen consumes half its volume of oxygen. He concluded from these and other facts that gases always combine together in simple proportions by volume and that the apparent contraction of volume they show on combining bears a similar simple relationship to the volume of one or more of the gases. Avogadro, working on Gay-Lussac's experimental data, suggested that the number of integral molecules in any gas is always the same for equal volumes, or is always proportional to the volumes. He also suggested that equal volumes of different gases at the same pressure and temperature contain the same number of molecules. Experiments on alcohol made by Williamson raised doubts as to the validity of Avogadro's hypotheses when applied to chemical combinations. These doubts were cleared in 1860, when the new chemical atomic weights and formulæ were introduced into English textbooks. The molecular theory of matter derived from these experiments supposes that all visible forms of matter are aggregations of simpler and smaller chemical elements. Mendeléeff and Newlands showed that the physical and chemical properties of the elements are functions of their atomic weights. Investigations of radioactivity and the observations based upon the passage of electric currents through gases have recently modified our views with respect to the atomic theory, but these points will be dealt with in the chapter dealing with radiation. Questions regarding the eventual loss of energy in matter are best studied in gases. A considerable number of important investigations are now being carried on in Europe with the view of tracing the interchanges of molecular energies in gas molecules. Maxwell and other investigators found long ago that the motion of molecules cannot go on perpetually. The energy of motion will in time be frittered away by friction, air resistance, collisions with other molecules, vibrations set up by collisions, and other molecular movements. It has been found that the energy which is dissipated by air resistance is transformed into energy in the air. That which is lost by collisions is converted into internal vibrations within each molecule. The question now arises as to what effects are exerted on a gas. It involves the effects of the communicated internal molecular vibrations and their transference of energy to the surrounding medium. What is known as the Quantum dynamic theory has been proposed to account for this phenomena. Quantum dynamics appear to be distinct from the Newtonian. Carnot and Clausius discovered that the motive power of heat is independent of the agents brought into play for its realization. The motive power of a waterfall depends, for example, on its height and on the quantity of water falling within a given time. Clausius stated the Carnot idea in mechanical terms by saying: That in a series of transformations, in which the final is identical with the initial stage, it is impossible for heat to pass from a colder to a warmer body unless some other accessory phenomenon occurs at the same time. A heat motor, which, after a series of transformations, returns to its initial state, can only supply work, or power, if there exist two sources of heat, and if a certain quantity of heat is given to one of the sources which can never be the hotter of the two. The output of a reversible machine working between two given temperatures is greater than that of any nonreversible engine, and it is the same for all reversible machines working between these two temperatures. Clausius showed that this principle conduces to the definition of an absolute scale of temperature and there is another factor assisting in restoring physical equilibrium which he termed entropy. It is a variable which, like pressure or volume, serves concurrently with another variable to define the state of a body. These discoveries of Carnot and Clausius showed the impossibility of finding a source of perpetual motion and helped to solve many of the difficulties in securing efficiency from internal combustion engines. Industrial, as well as scientific results of immense importance have developed from these principles. Theories on the compressible fluids and elastic equilibrium were developed as the result of work done between 1875 and 1896 by J. W. Gibbs, Helmholtz, Duhem, and others on internal thermodynamic potentials. These theories have proved of incalculable value in elucidating electrical and radiation phenomena. Another discovery of Gibbs, made in 1876, has also had brilliant results. It is known as the Phase Law. The homogeneous substances into which a material system is divided is called a phase. Carbonate of lime, lime, and carbonic acid gas are the three phases of a system which comprises Iceland spar partially dissociated into lime and carbonic acid gas. The number of phases, combined with the number of independent bodies entering into the reactions, fixes the general form of the law of equilibrium of the system. This discovery of Gibbs has resulted in greatly extending the field of physics. It is of importance in molecular and atomic investigations, in osmosis, electrolysis, and in most questions dealing with thermodynamics. Light is generally defined as the sense impression received by the eye. It was formerly believed that it was caused by streams of corpuscles emitted by the source of light. This was known as the emission theory. Early in the nineteenth century, the undulatory displaced the emission theory. According to this, light is a transverse vibratory motion extended longitudinally through the ether. The experiments of Faraday, Maxwell, Fresnel, Hamilton, Green, and others suggested that the undulatory theory required for its validity a new medium different from the atmospheric air and from every substance known to man. Just as the results of investigations into reflection, refraction, diffraction, and polarization showed that the old corpuscular theory of light was untenable, so these experiments seemed to cast doubt upon both the undulatory and emission theories. Fresnel, when studying problems in polarization, noticed that a theory of light proposed by Hooke appeared to be true. Hooke asserted that light vibrations are not longitudinal but transverse. Fresnel found by his experiments that the idea of longitudinal vibrations acting along the line of propagation in the direction of the rays would not explain the polarization changes in light. They suggested that there was a transverse movement perpendicular to the ray. When Fresnel's researches were published, physicists realized that if the transverse direction of luminous vibrations was denied the undulatory movement of light would also be denied. Now transverse vibrations cannot exist in any medium resembling a fluid, because it is characteristic of fluids that, so long as the volume continues constant, its different parts can be displaced without the appearance of any reaction. This necessitates the assumption that light needs a solid body for its transmission and Lord Kelvin asserted that this body must be a solid more rigid than steel. When the vibratory theory was accepted, it became necessary to investigate the nature of the ether and to determine its characteristic properties. Neumann, MacCullagh, Green, and Stokes then developed an elastic solid theory of the ether. The experiments of Lord Rayleigh, Lorentz, Drude, Larmor, and others suggested that light is identical with electromagnetic disturbances and, consequently, is an electrical phenomenon. Some of the finest developments in physics during the nineteenth century were in the realm of electricity. They resulted in an enormous extension of the use of electricity in industry and commerce and led to the investigation of radioactivities of various kinds and these in turn are developing investigations of a most brilliant character. CHAPTER XI THE NATURAL SCIENCES Manifestations of animal life are everywhere visible. They may be seen on mountain peaks, in desert plains, and by the seashores. Even the bleak arctic ice fields have their faunas. This extraordinary distribution of life has attracted attention since the dawn of history. Primitive man, by his often beautiful cave drawings, indicated that he studied intimately the wild life surrounding him. The basic facts of natural history were studied by the early peoples of the Near East. The Greeks prepared many books on natural history and anticipated modern evolutionary theories. The natural sciences, however, made slow progress until toward the end of the eighteenth century when Linnæus and Buffon began their great works. When the nineteenth century opened, the broader fields of nature were segregated, classified, and described. Linnæus took broad views regarding the principles of classification based upon general structure, and his work was enlarged and improved by Cuvier. Buffon contributed suggestions regarding the probable mutability of species with respect to changes in environment, and improved on the old Greek evolutionary ideas by formulating a definite theory of the causes of mutability. He was an important agent in promoting the modern theories of evolution in zoölogy and botany, which have done more than anything else to augment our knowledge of terrestrial life. The numerous scientific exploring expeditions in the eighteenth and nineteenth centuries collected an enormous amount of data regarding animals and animal life. Early in the nineteenth century this data was worked up and classified. It soon became apparent that the range of any given species of animal is strictly limited. A new science, that of the geographical distribution of life, was developed. This has been very fruitful in defining the true home areas of all species of animals, insects, birds, and fish, and locating their principal paths of migration. The world has been divided into about a dozen terrestrial life regions, subregions and transitional regions. These have been mapped and described. The work of Dr. A. R. Wallace, in 1876, showed the comparative importance and extent of these life zones and their variable richness in zoölogical forms, the relationships of the species in different zones, and their degrees of isolation. The descriptions of these great geographical zones fill many interesting volumes and cover all the important forms of existing life. The naturalists who studied particular zones, or classes of animals, frequently did extraordinary work. The bird studies in North America, recorded in a series of wonderful paintings by Audubon, and the studies of Fürbringer and other naturalists, are comparable with Wallace's great book on the Geographical Distribution of Animals, published in 1876. The morphological researches of Parker, Huxley, Quatrefages, Owen, and others revolutionized many of the subdivisions of natural history and led to important discoveries in biology. The effects of climate upon the development, migration, and decline of species and upon the extension and upbuilding of civilization have been minutely studied. Kropotkin showed that climatic changes in Asia drove the hordes of native tribes into Europe at early periods. They were forced to migrate on account of droughts leading to a food shortage. Many historical events have been shaped by climatic factors. Just as men who inhabit dry districts are usually nomads on account of their need of seeking new food supplies, so animals and insects are forced to migrate for a similar reason. The life changes wrought by disease epidemics under climatic influences have also been studied and have shed much light upon the origin and development of many organs and upon the habits of animals. Some of the chief inferences arising from investigations on the effects of climatic variations on life are that certain types of climate favor the development of certain animal species; certain climates have prevailed in historical times in centers where civilization flourished greatly. Therefore it may be presumed that definite climatic conditions are required for the specific development of each type of species and for each kind of civilization. Just as history shows that one of the many conditions of human progress has changed repeatedly from century to century on account of variations in climatic factors, so these stimuli have, from the earliest times, swayed and modified all classes of organic life. Climate serves to develop, retard, or extinguish animal characteristics, habits, and development. The study of the rôle of climate in modifying living conditions has disclosed data which throws much light on the philosophical problems surrounding organic life, its laws and progress. The voyage of the _Beagle_ in 1831, for a scientific cruise to South America, with Charles Darwin aboard as naturalist; that of the Ross Antarctic expedition in 1839, with Sir W. J. Hooker as botanist; that of the _Rattlesnake_ for Australia and the South Seas in 1846, with T. H. Huxley as surgeon, resulted in the assembling of scientific data in natural history fields which, when classified and developed, revolutionized the natural sciences. The work of the _Challenger_, in 1872, and many other memorable British scientific expeditions augmented and confirmed the data collected in the earlier explorations. Harvey's explanation of the movement of the blood by the pumping pulsations of the heart quickened interest in biology. Mayer and Helmholtz, when chemists, had succeeded in artificially making urea and sugar and investigated living organisms from the viewpoint of mechanisms operated on the principle of the conservation of energy. They traced the manifold functions of the body to chemical and thermal energies developed by the destruction of food. These valuable discoveries were augmented by Schleiden and Schwann, showing that all organisms are built up of living cells. The offices performed within cells by colloids and solutions, and in the nerves by electric movements, were traced. Investigations into the most minute forms of animal life also furnished startling results. Schwann found, in 1838, that fermenting yeast consists of living vegetable cells, and that organic putrefaction is caused by the activities of such cells. Louis Pasteur (1822-1895) demonstrated that the presence of bacteria in any animal is always due to the entrance of bacteria and microbes from the outside, or by means favoring the abnormal increase of existing germs. He also showed by experiments that diseases like chicken cholera, phylloxera, or the silkworm disease are caused by particular microbes. These discoveries led to the tracing of many common diseases to their special living germs. While these impressive additions to scientific knowledge were being made, other naturalists were studying the instinctive emotional and intelligent behavior and psychology of animals, both singly and in herds. Animals and insects were found to display signs of intelligence, sometimes of a high order; to live socially, in many cases; and to play and court with emotional attributes. Throughout the animal kingdom, until man is reached, animals are guided in their activities by self and racial preservation. Play was found to be a fruitful factor in animal education, even in minute insects. The behavior of any animal does not stand alone, but is related to that of others. Animals which hunt, or are hunted, combatants, rivals, mates, and enemies, react upon one another. Entomology, the science of insects, has been extensively systematized. Practically every phenomenon relating to the insect metamorphosis has been disclosed. The works of Binet, Lubbock, Fabre, and many others have illuminated the psychology of insect life. The charming writings of J. H. Fabre on the life of a fly, on the mason bees, the hunting wasps, the life of a caterpillar, of a grasshopper, of the sacred beetles and other insects, are as thrilling and instructive as any masterpiece of romantic writing. What could be more interesting than Fabre's account of his observations on the glowworm, when he discovered that its luminescence is due to oxidation by air forces through a special lightning tube, and that it occurs in males as well as females and in the eggs and grubs likewise? He shows that the glowworm's life, from start to finish, is one carnival of light. The females are living lighthouses which brilliantly illumine the wild thyme and other flowering plants they haunt on dark nights, making miniature fairylands in country districts. Studies in the growth and form of living bodies have opened up many interesting problems in physical biology. The cell and tissue, shell and bone, leaf and flower are various portions of matter, the particles of which are moved, molded, conformed, or shaped in obedience to the laws of physics. Forms like those of the lovely wing scales of butterflies, of lace flies, or the spiral shells of the foraminifera are natural diagrams of the results of physical forces. Biologists not only study the nature of the motions of living organisms as animal kinetics, but also the conformation of the organism itself, whose permanence or equilibrium is explained by the interaction or balance of forces leading to static conditions. The dynamics of cell formation and cell division and their karyokinetic figure drawings are the result of numerous complex physical force struggles brought about by chemical and physiological reactions. Studies of these have shown that the spermatozoön, nucleus, chromosomes, or the germ plasms, which develop organic life, can never act alone. They must be started by other forces which make them seats of energy. The experiments of George Rainey on the elementary formation of the skeletons of small animals, of Carpenter upon the formation of shells, and those of Professor Harting on the same subjects, have shown how lime solutions acting in conjunction with gelatinous substances, or membranes, build up the numerous geometric shapes of the frames of so many kinds of primitive organisms, and the scales of fish or the extraordinarily beautiful markings and sculpture of shells. The application of the Cartesian coordinates to the outline of organisms, skulls, bones, and organs of animals has opened up a new field of mathematics--biological research which has yielded many results confirming theories based on other data and supplying facts of great interest that may at any time result in the establishment of important generalizations. The fact of beauty in animate nature is so pronounced, and man's contemplative delight in beautiful things is so natural that investigations have been made into the æsthetic emotions of other animals. A vast array of facts has been collected which leaves no doubt of the universal appreciation of beauty. The lovely colors of shells, butterflies and birds, the extraordinary beauty of the designs of the frames of the Foraminifera, radiolarians and sponges, the graceful logarithmic spirals of horns and flower and leaf buds, and the charming flowing lines in the shape of the race horse and gazelle, these elements of organic beauty which emphasize and enhance the forms of animals, all contribute to the general embellishment of nature. The combinations of beauty of form, color, and movements in parrots, humming birds, the fish inhabiting coral reefs, butterflies, and orchids, are always perfect. We likewise find that in all parts of the globe, and in each life zone, organic beauty conforms to that of the landscape and the heavens. The biological significance of this universality of beauty in the organic world will be dealt with in the following chapter. The fishes of the seas, rivers, streams, and lakes have been studied, classified, and described as completely as the insects of the air, the field, the soil, and those parasitic upon other organisms. The surveys of the Atlantic have brought to light many types of fish which inhabit only the deepest parts of the ocean. These fish are modified in most extraordinary ways to fit their surroundings. Owing to the darkness of their living zones, they are provided with luminescent appendages which are practically similar to the firefly's and glowworm's electric generators. The lights are formed, as in the insects, by the oxidation of material exuded by the fish. There are more than 180 families of fishes recorded. Each family contains an average of twenty genera and each genus about five species. The known species of fish are, therefore, between 19,000 and 20,000. The Danish naturalist Hensen found 278,795,000,000 fecundated fish eggs per square mile in the summer waters of the Skagerrack. The waters of the seas from the Arctic to the Antarctic limits are full of fish eggs as well as those of shellfish and sea organisms generally. This shows that organic life is as abundant in the sea as anywhere on land. Just as temperature and salinity are the chief agents of oceanic circulation and current movements, so they are the leading factors in promoting the organic life of the sea. The vast heterogeneous mixtures of living creatures, comprising vegetable and animal organisms, larvæ, and eggs of fish and animals, which are swept hither and thither by the sea tides are called plankton. This term means the living dust or emulsion of the sea. It has been shown that vegetable plankton is composed of bacteria and adult microscopic algæ, largely of the Diatomaceæ, Peridinaceæ, Cyanophyceæ, and other primary groups. The animal plankton comprises a mass of microscopic creatures belonging to the Protozoa, Radiolaria, and Globeriginæ. There are also immense numbers of tiny, invisible crustaceans like the Copepoda, and eggs and spores of all kinds of fish and algæ. These organisms are so dense in certain sea areas that their particular colorations are reflected in the water. The Red Sea, for example, is colored by a reddish algæ; the Baltic and ocean areas near Greenland are colored green by swarms of algæ, and certain tropical seas are often brilliantly colored in the same manner. Plankton furnishes fish with nutriment. The study of the movements of plankton, at seasonal intervals, has led to the discovery of the causes, extent, and results of the migration of the principal commercial fishes. These researches are so valuable that most large nations support marine biological stations and ships to regularly make observations. The Norwegian naturalist Särs, Sir John Murray, the Prince of Monaco, and others have furnished accounts of the life histories, feeding grounds, metamorphoses and migrations of many fishes, and have shown how the inhabitants of the plankton masses live upon themselves or produce nitrifying or denitrifying bacteria, chemicals, and mineral substances like lime, phosphates, and horny membranous material. The development of biology and embryology, and the peculiar habits and color schemes of certain fish, insects, birds, and animals led to inquiries about design in nature, the causes of the development of species, and the instincts and habits of animals. Erasmus, Darwin, Buffon, Cuvier, and others began these studies, but it was Charles Darwin (1809-1882), who by the publication of his "Origin of Species" in 1859, first furnished many of the keys to the riddles of organic life. The next chapter will show what has developed from his labors. CHAPTER XII ORGANIC EVOLUTION, VARIATION, AND HEREDITY Science developed when primitive man began pondering over the problems of the creation. He sought the causes of life, of the development of life forms, and the authorship or origin of the uniformity and apparent design in nature. It is, therefore, probable that what we now study as the science of organic evolution is one of the oldest of the sciences. As the ages have rolled on, the origin of life has been explained in turn by theories of: (1) eternity of present conditions; (2) miraculous creation; (3) catastrophism with (a) increases by immigration (b) increases by successive creations; and, finally, by (4) organic evolution. The term organic evolution means the forming of new combinations of the elements of organisms. It does not mean the arising of an animal or plant out of nothing--a new creation. That idea was exploded long ago. The science which Darwin started surveys the whole course of natural history in terms of four dimensions--length, breadth, depth, and duration. This was the plan which led Darwin to his great discoveries. While studying the minor changes taking place in common animals and plants, and looking over the broad vistas of nature back to the remotest times, he saw how each year countless weak and ill-adapted plants, insects, and animals were killed off. When he reflected that this process has been going on throughout all time, the idea flashed into his mind that it is through this testing ordeal that adaptability of surviving organisms is derived. One of the grandest conceptions of the human mind is that the apparently complex, inharmonic system of nature has developed from a simple beginning on a cooled globe from a jellylike cell. The theory of the permanence of species was generally held by biologists before publication of Darwin's first great book. Darwin said that no naturalist of his time doubted the accuracy of the theory of the eternity of existing conditions and they refused to listen to his views regarding the mutability of species. Darwin put forth the theory of organic evolution by natural selection and the survival of the fittest. The great beauty of this theory lies in its simplicity and its appeal to agencies which we can see in full operation every day and night. The skillful manner in which Darwin marshaled data to substantiate his theory quickly converted the scientific world, and led to revolutionary changes in the general tendencies of knowledge, and in practically all fields of human activity. Darwin's terse statement of his conception was: "As many more individuals of each species are born than can possibly survive, and as consequently there is a frequently recurring struggle for existence, it follows that any being, if it vary in any manner profitable to itself, under the complex and sometimes varying conditions of life, will have a better chance of surviving, and thus be naturally selected. From the strong principle of inheritance any selected variety will tend to propagate its new and modified form." ("Origin of Species," Intro.) This statement of the doctrine of the survival of the fittest, suggesting a glimpse at the great pageant of nature from the remotest times, shows how the organisms existing at this moment are the descendants of the victors in the world's greatest battles. The struggles for life, always keen and persistent, shared in by every individual organism, both animal and vegetable, are the instigators of all progress in the natural world. They are nature's means for the attainment of beauty, usefulness, and perfection. The Darwinian theory was based upon the observed facts that members of any given species are not alike, while their offspring may differ in numerous ways from their parents. The data furnished by zoölogy, botany, physiology, and other sciences supply overwhelming evidence that the present species of animals and plants have arisen through the modification from various causes of many pre-existing species. The organisms with which we are familiar owe their characteristics to the accumulation of a long series of changes similar to those that we may see that they are still undergoing. The methods pursued in studying variation in species, and its important accompaniment, heredity, consists in comparison, statistical examinations, cultural experiments, and crossbreeding. Evolution is the process of differentiation accompanying the operations of nature. All the great naturalists before Darwin's time noted facts indicating this universal differentiation, but it required the particularly wide sweep of Darwin's mind to phrase and demonstrate it. The law of origin by evolution, as Herbert Spencer showed, is not confined to the method of bringing into existence new species of animals and plants. The stars, planets, the geological strata and earth contours and forms, human institutions, social customs, and practically everything in nature are obedient to it. Much research work in evolution has been done since Darwin stated his theory, but the basic principle of the survival of the fittest remains untouched by criticism. Some of his views respecting minor details of selection and the effects of various factors have been modified or enlarged, and many new evolutionary forces have been discovered. It has also been found that a single cause is usually followed by more than one effect. Weissmann has drawn attention to the importance of adaptations. Most organic beings are usually closely fitted for the conditions under which their lives are spent. The principal parts of every animal and plant, and all the points in which one species differs from a nearly related species, have been shown to have arisen on account of their usefulness to the creatures possessing them. As natural selection is always progressive, it follows that no adaptation is ever perfect. There is always progress from the useful to the more useful--a continual striving for greater beauty of form and color and higher efficiency. Works on evolution furnish an abundance of interesting evidence showing how adaptation works. A single instance may be cited here. One of the Mexican yucca plants common in our Southern States is pollinated by a moth of the Pronuba family. This moth is adapted for its work by several special organs including a special ovipositor and peculiar maxillary tentacles which are not found in other moths. The female moth collects pollen with these tentacles from several yucca flowers, rolls it into a ball and kneads it into a pellet. When the pellet is ready the moth seeks an unvisited flower and, after depositing a few of her own eggs in the ovary, she climbs the style and forces the pollen pellet into the stigma. This is the way the yucca is pollinated and fertilized. Two important purposes are served by this arrangement: a species of plant and a species of moth, together with those dependent upon them, are enabled to survive by this moth's activities. There are many known cases of similar cooperative adaptation to living conditions. Quetelet, in 1845, followed by Francis Goltin and Karl Pearson, have applied statistical methods in dealing with evolutionary problems, and a new science called biometry has been developed. This science has yielded much important data regarding the effects of inherited characteristics. The studies of variations in plants by mutations, made by the Dutch botanist De Vries, have opened up wide fields of study regarding the causes of variation. He has shown that increased bulk or better coloration may result from improved nutrition and more light, and that such improved characteristics may be inherited. A law of ancestral heredity has been worked out for men by biometricians, and this has been confirmed by the experiments of Professor Johannsen, of Copenhagen, on self-fertilizing beans, and by Jennings on protozoa. This hypothesis suggests that every ancestor of a particular man or woman contributes its quota to the heritable qualities displayed by that individual. The average amount of resemblance between an individual and any of his particular ancestors is capable of being numerically expressed. The experiments and conclusions of Gregor Mendel (1822-1882) tend to oppose the law of ancestral heredity, but it is believed that any exceptional cases may be explained by the operation of special conditions. Karl Pearson has shown by the analyses of numerous statistical records of Englishmen that by artificial selection any selected characteristic, such as facial contour or stature, can be changed within a few generations. But when the character has been changed about 90 per cent within a short time another method must be employed, because the original one then becomes less efficient. Individuals in any given population who differ in size from the mean of the population give rise to offspring which differs from that mean value in the same direction but to a smaller extent. The same law applies to the color of the hair or to intelligence or constitution. Selection will always produce a change in the average character of a population taken as a whole. But selection within a pure line, or one which shows only normal variability about a mean or type value, does not produce marked changes. The usual selection within any particular population consists in the partial separation of extreme types. The personal characteristics of any ancestor do not influence his descendants. Only the typical characteristics are handed down. These and many other facts developed by investigations in biometry should be of value in regulating immigration, so as to guard against degenerative influences, and they have greatly increased the efficiency of farming by showing how to improve farm stocks and crops so as to yield larger returns. Farmers have been more ready than politicians to avail of their advantages. We note how the speed of racing and trotting horses, and the milking capacity of cows, have been improved by the past century, but we are doing little to reform national health and efficiency. Mutation is the name given to the process of origination of a new species or character accomplished by a single step or by a series of steps. Bateson, in 1894, showed that symmetry is a characteristic common to all organisms. This may affect the whole or parts of an organ. Major symmetry involves the whole organism and minor symmetry only an organ or part. There are meristic variations, involving the symmetrical pattern, and substantive variations involving changes in the constitution or substance of the organism. Red-flowering plants, for example, may yield offspring bearing white flowers. Substantive variations are often discontinuous, or accidental, and are infrequent. Organic bodies are built up of a number of cells. The living material of cells is protoplasm formed out of many elements, of which carbon, oxygen, hydrogen, nitrogen, and sulphur are the more important. New cells arise from bipartition of existing cells. Therefore by following back the history of any animal or plant we will arrive at a stage when its ancestors had only one cell. Every animal or plant which is propagated sexually actually starts as a cell and develops through its main evolutionary changes in the embryonic state. Cells are liable to all the evolutionary changes that the organism as a whole is subject to. Studies of embryology have shown that the fusion of biparental reproductive cells results in the formation of a complete new individual which, at the time of the fusing of the two conjugating cells, called gametes, or germ cells, inherits the characteristics of each parent and its ancestors. The determination of the sex of the cell, plant, or animal, depends upon the presence of extra male or female sex-chromosomes, or sex-determinant fibers of the cell nucleus. Certain animals and plants transmit male characteristics to the female descendants, while the female transmits her characteristics to the male descendants. There are many variations of this kind. These strange movements in heredity are explained by the laws governing chromosomes and idio-chromosomes and elementary cells. According to the germ plasm theory of inheritance, the separate parts of living organisms are assumed to be represented by separate material particles in the germ cells. In the Mendelian theory each cell is assumed to contain a large number of _ids_, or complete sets of sex determinants, half the total being derived from each parent. This permits the germ cells to contain a certain number of ids from each parent. Studies of these subjects show that the great harmonies of the natural world are manifested in form, number, pattern, and color, which we find to be basically simple and, when studied systematically, they appear quite clearly, so as to be capable of being described and expressed as laws. The study of the agencies under social control which may improve, or impair, the racial qualities of future generations, either physically, socially, or mentally, is called the science of eugenics. This new science is another outgrowth of the revolution in intellectual development originating with the publication of Darwin's theory. Sir Francis Galton was the pioneer worker, and he has been followed by Pearson, Yule, Lombroso (1836-1909), and others. Eugenic studies, confirmed by those of genetics and biometry, show that the human race, which is the masterpiece of Nature's evolutionary processes, is capable of much further development through the careful guiding of the very forces used in evolving man to his present state. Man can be improved by selection and education to greater beauty, clearer intellect, larger stature, sounder character, and better physique. The measure of what man has done is a good criterion of what he is capable of doing under the guidance and encouragement of science. Genetics, the study of the hereditary phenomena of organisms, is based upon the law of inheritance discovered by Mendel in 1865. This law relates to the inheritance of certain definite characters called allelomorphs. These characters are found to group themselves in pairs which exhibit more or less antagonistic qualities. A knowledge of these characteristics is necessary to conduct selective breeding experiments scientifically. It is found that when two similar germ cells, each bearing the same new combination of allelomorphs, meet in fertilization, they result in the development of a new zygotic combination of a pure type which breeds true. This accounts for the establishment of new species. When, on the other hand, the coupling is unequal, or only partial, there will be irregularities in the characters of the offspring and no new species is likely to develop. Immense value is attached to this law by naturalists working in all fields. The three new sciences of eugenics, genetics, and biometry have prepared the way for a regeneration of humanity through breeding in the desirable and breeding out the undesirable. CHAPTER XIII CHEMICAL AND BOTANICAL THEORIES The World War served to demonstrate the degree of perfection which has been attained in chemistry. The wonderful high explosives used, the poisonous gases, the lubricating and motor oils and a multitude of valuable chemicals employed for military and naval purposes, many of which were developed at short notice, showed the modern chemist's command of his science. Yet chemistry is a new science. Practically it began with Robert Boyle, in England, in 1661. Boyle conducted experiments on the rarefaction of air and the nature of gases, and in his book, "The Sceptical Chemist," he made this remarkable statement: "I am apt to think that men will never be able to explain the phenomena of nature, while they endeavor to deduce them only from the presence and proportions of such or such ingredients, and consider such ingredients or elements as bodies in a state of rest; whereas, indeed, the greatest part of the affections of matter, and consequently of the phenomena of nature, seem to depend upon the motion and contrivance of the small parts of bodies." Thus Boyle anticipated the chemical theories of matter developed in the nineteenth century. Lavoisier, about 1777, advancing from the quantitative study of one chemical change to another was able to describe many processes, and to distinguish between an element and a compound. He cast aside all the alchemical formulæ and expressed the results of his experiments in fractions and proportions. J. B. Richter between 1791 and 1802 made a series of experiments by which he secured the weights of various bases neutralized by constant weights of several acids, and the weights of several acids neutralized by constant weights of several bases. He found that the composition of chemical compounds is constant, as had been assumed by Lavoisier and Boyle. Dalton described the atomic constitution of gases in 1808, and sketched the law of multiple proportions in chemical combinations and described binary, ternary and quaternary combinations. Prussic acid was investigated by Gay-Lussac in 1815, when he isolated cyanogen and found that although it is a compound it plays the part of an element with hydrogen and the metals. Berzelius also found that ammonium possessed all the properties of an alkali metal. Ten years after the above discoveries were made, Faraday prepared a compound of carbon and hydrogen from liquefied coal gas which led to the general study of isomerism and the great discoveries of the organic radicals with their important combinations. When isomeric combinations were studied by Jacob Berzelius (1779-1848), he was led to devise a means of expressing organic reactions. He wrote to Wöhler and Liebig a letter outlining his new method in which he said: "From the moment when one has learned to recognize with certainty the existence of ternary atoms of the first order which enter compounds after the manner of simple substances, it will be a great relief in the expression of the language of formulæ to denote each radical by its own symbol, whereby the idea of composition it is desired to express will be placed clearly before the eye of the reader." [Illustration: Photo, Fifth Avenue Hospital ROOM IN WHICH INFECTED ARTICLES ARE STERILIZED] [Illustration: MODERN OPERATING ROOM IN A PARIS HOSPITAL. IT IS FITTED WITH A GLASS DOME AND RADIO MICROPHONES FOR THE USE OF STUDENTS AND DOCTORS WHO WISH TO WATCH THE OPERATIONS AND HEAR DISTINCTLY THE COMMENTS OF THE SURGEONS] An example of this method of expressing reactions was given in the case of the action of chlorine on benzoic acid. He wrote B₂O for benzoic acid, B₂CL₂ for chlorbenzol and B₂ + NH₂ for benzamide. With certain simple improvements made subsequently by Gmelin, the method devised by Berzelius was generally adopted and is in use to-day. The numerous investigations now being made with the object of discovering the various combinations of the elements led to many improvements in chemical analyses. When we read Berzelius' accounts of his analyses they seem to have been written only yesterday. He and his contemporaries developed analytical and synthetic methods to almost the efficiency that we see to-day. We also owe to Berzelius a table of the elements showing their electrical qualities, an electrochemical theory, identifying chemical affinity with electric attraction, and a new nomenclature, besides a vast amount of descriptive chemistry. The discovery of the specific heats of various solid elements by Dulong and Petit in 1819, and Mitscherlich's finding of the isomorphic phenomena in 1818, resulted in the publication of a new atomic weight table in 1826 by Berzelius. The experiments made in isomorphism by Mitscherlich led him to discover dimorphism and study crystallography. He used his knowledge of crystal measurement extensively and developed synthetic chemistry and the laws of crystallization. Thompson, Prout, and Wollaston were working on problems in England similar to those examined in Sweden by Berzelius and Mitscherlich. Molecules were discriminated from atoms in 1826 by Jean Baptiste Dumas and Faraday discovered his law of electrochemical action in 1834. Organic chemistry originated in Manchester, England, when Dalton read his paper before the Manchester Philosophic Society in 1803 on the theory of atomic weights. This paper led Gay-Lussac, Thenard, Berthollet, de Saussure and others to study organic analyses as devised by Dalton. Gay-Lussac and Thenard greatly improved Dalton's methods and in 1824, as shown by Chevreul's work on fats and greases, organic analyses had been brought to high perfection. The phenomena of substitution in hydrocarbon compounds like the petroleum oils were studied by Laurent who proposed a theory of basic nuclei. C₁₀H₈ being the nucleus of the naphthalene group and C₂H₄ that of the ethylene group, derived nuclei can be obtained from these by substitution and hydrogen and other elements acting on derived nuclei from numerous hydrocarbon series. The homology of the hydrocarbons was discovered by Gerhardt in 1844 while he was investigating the alcohols. Wurtz's work on the ammonia compounds, Williamson's on the ethers, Hoffmann's on anilines, Graham's and Liebig's on the citrates, and Frankland's, Kolbe's and Kekulé's work on other compounds raised organic chemistry to such a high plane that industrial chemists were able to use their theoretical conclusions and build a great number of important industries upon organic principles. Lothar Meyer, in 1868, and Mendeléeff, in 1869, published atomic weights showing improvements in the theories of valency and the interrelationship of atomic weights. Mendeléeff was able to predict from the vacant positions in his table the discovery of important new elements. A number of these elements have since been discovered. The aniline dye industries have grown out of the discoveries of many chemists. The basic work was done by Faraday, Laurent, and Runge, who isolated valuable hydrocarbons from coal gas tar. Hoffmann discovered aniline and Perkin obtained mauve in 1856 by the oxidation of aniline with chromic acid. It was this and subsequent discoveries by Perkin which gave the greatest impetus to synthetic dyes. The solubility of a dye was improved by increasing its acidity (sulphonation) or by increasing its alkalinity (alkylation). Similar dyes are now made by the same methods from many common aromatic substances. The chemistry of explosives was developed by Van Helmont, Debus, Bunsen, Abel, Nobel, and, others. Fulminates were used for detonators by Ure in 1831, picrates were employed as explosives by Fontaine and Abel; nitrocellulose (guncotton) discovered by Braconnot in 1832 and used as an explosive by Schönbein in 1846, and nitroglycerine was produced by Sobrero in 1847. Smokeless powders made from guncotton, dynamite, and gelatine were introduced by Nobel in 1890. Pasteur showed, in 1848, that when the double sodium ammonium racemate was crystallized, two kinds of crystals separated from the solution. When one set of crystals was dissolved in water the solution rotated a beam of polarized light to the left, while the aqueous solution of the other crystals rotated the light to the right. These crystals thus revealed their geometrical properties with perfect light while in solution in water. Pasteur noted that optical activity of this kind is the expression of some form of molecular asymmetry. Le Bel in 1874 also pointed out that optical activity is an expression of the asymmetry of the chemical molecule and showed that all carbon compounds which are optically active contain a carbon atom combined with four different atoms, or groups. Van't Hoff showed in 1875 that there were definite relations between the arrangements of tetrahedral carbon atoms and polarization phenomena and established the theory of such atoms. Willard Gibbs, of Yale, discovered what is known as the phase rule, which shows, by thermodynamic methods, how the conditions of chemical equilibria can be systematically grouped. Van't Hoff, Pfeffer, and others noticed that when two solutions are brought together, if one is more concentrated than the other, diffusion begins in the concentrated and extends to the weaker solution. This shows a talent force in concentrated solutions which is now known as osmotic pressure. Van't Hoff and Arrhenius showed that for comparable concentrations the osmotic pressure of a solution is exactly equal to the pressure of a gas. These discoveries led to a brilliant series of investigations into electrolytic chemistry. The theory of electrolytic dissociation advanced by Ostwald shows that the molecules of electrolytes in aqueous solutions are broken down into electrically charged parts called ions. In very dilute solutions the dissociation of strong acids, bases, and salts is practically complete as was suggested by Williamson in 1851. Catalysis, or reaction brought about by agents which do not enter into the chemical changes, was discovered by Berzelius. Ostwald investigated and developed catalytic reactions which are now extensively employed in industry, particularly in refining oils and in the fixation of nitrogen. Hot platinum, for example, is used to act catalytically in causing sulphur dioxide and oxygen to combine and form the basis of sulphuric acid, sulphur trioxide. One of the most important applications of catalysis to industry is the Haber process for securing nitrogen from the air. When air and hydrogen are compressed and heated to a high temperature in the presence of a catalyzer such as metallic uranium or iron carbide, the nitrogen and hydrogen combine and form ammonia. The experiments of Sir William Crookes on vacuum tubes subjected to electrical impulses led the way to the discovery of radioactivity, and investigations of radium have revolutionized our conceptions of the nature and properties of matter. The discovery of helium, argon, the niton emanation from radium and other elements by Ramsay, Collie, Soddy, and others will be referred to later. Carl Linnæus, who is called the father of modern botany, established the genera and species of plants upon philosophical principles. He established a binomial nomenclature and formulated modern descriptive methods. Thus he prepared the way for the systematic works of De Jussieu and De Candolle. De Candolle, in 1819, published a new method of classification based upon morphological characters. He defined and illustrated the doctrine of the symmetry of plant organs and asserted that a natural classification must be based on a plan of symmetry. The relationships between the endosperm and embryo were shown in 1810 by Robert Brown in his monograph on the Australian Proteaceæ. The morphological nature of seed reserves was described by him. He also discovered the functions of the cell nucleus and founded cytology. He showed that the oscillation of minute particles in the fluids of plants when viewed under high microscopic powers, known as the Brownian movement, is due to purely physical causes. Schultze, Unger, and others, working on suggestions previously made by Knight, Robert Brown, and Hooke, discovered the rôle of protoplasm in plant cells. Alexander Braun and De Bary correlated the movements of protoplasm with the locomotory movements of free zoögonidia and the amœboid movements of Mycetozoa. These investigations directed research to further studies of the structure and constitution of protoplasm and helped develop the cellular theory. The Algæ were studied and classified by Naegeli, Unger, Von Mohl, Haustein, and others in 1847-1850. The vascular cryptogams were studied by Hofmeister. He found that the alternation of a sexual with an asexual generation is common to all plants of the mosses, vascular cryptogams, and gymnosperms, as well as among angiosperms. Hofmeister's work led to appreciation of the fact that a natural system of plant classification must be based, not on balancing the values of the morphological parts of fruits and flowers, but on the anatomy of the real and concealed reproductive organs. Fossil botany, or paleophytology, was founded, in 1828, by Adolphe Brongniart. Witham, Goeppert, Unger, Corda, and others helped to advance this science. The publication of Darwin's "Origin of Species" in 1859 found the various botanical sciences already well worked out by numerous capable experts. A huge amount of data and descriptive matter had been assembled and botany, like the other sciences, was ready to be quickened by the Darwinian theories. The idea of a progressive evolution in plants had been suspected by many botanists, but the genius of Darwin developed it. Living plants were pictured as a multitude of units competing for food, light, air, and room for growth, and struggling against unfavorable environments. The classification of tissues was begun, and the phenomena of absorption of water and salts, the ascent of sap, the absorption of minerals and nitrogen, and metabolism and growth were elucidated. Investigations were made into the nature and functions of chlorophyll and other plant substances. These studies resulted in suggesting means for improving crops by artificial selection, as shown in the work of Luther Burbank. CHAPTER XIV GEOLOGY, METALLURGY, AND METEOROLOGY Geology is essentially a nineteenth century product. Fossils, minerals, rocks, and rock strata had attracted more or less attention from the earliest times. The Egyptians, Greeks, and Romans had books dealing with such subjects, and Greek philosophers, like Aristotle, lectured upon them. But it was only in the last century that geology was placed upon a scientific basis and began to make progress. The reformation was begun by Cuvier's work on paleontology, the chemical and physical discoveries of the eighteenth century, and the works of Hooke, Boyle, Buffon, Linnæus, and others. The special technique required in geographical research could not be developed until the biological, anatomical, botanical, and physical sciences had been established on a scientific plane. That is why geology remained for so many centuries undeveloped, and then rapidly advanced during the nineteenth century. Its preparation was long and involved, while its fruition was rapid and brilliant. William Smith (1769-1839), called the father of English geology, was a mining surveyor engaged in making colliery and farm surveys in Oxfordshire and the west of England. His professional work led him to study the coal outcrops, and in 1793 he mapped the inclined coal deposits in Somersetshire. The numerous rock strata accompanying the coal beds contained fossils which he found could be used to identify the beds in that field with others in northern counties. He published an account of this manner of using type fossils for identifying fossiliferous rock formations in 1799, and in 1815 issued his geological map of England, Wales, and southern Scotland. This map showed the advantages that scientific geology and mineralogy offered to industry and caused scientists all over Europe to study geological phenomena and make sketch maps of local geology. A work on paleontology, dealing with the fossils of the Old Red Sandstone deposits, published in England by Hugh Miller (1802-1856), which had an enormous popularity and has been described as the most fascinating book ever written on a geological subject, followed Smith's "Strata Identified by Organized Fossils." A large amount of mapping resulted from the issuing of these two works. These maps called for detailed descriptions, and these in turn resulted in the accumulation of many interesting data which, when collected, and systematized, led to many important discoveries. While these authors were preparing their books, Werner, De Luc, De Saussure, Lamarck, and others were working out paleontological problems, Romé de l'Isle, Brongniart, Haüy, d'Aubuisson, and others were building up the science of mineralogy. "The Theory of the Earth," of Dr. James Hutton (1726-1797), was published in 1785, and in an enlarged form in 1795. This book described the metamorphoses of sand into sandstones, quartzites, schists, and other rock formations; the work of floods and lava floods; the sculpturing powers of streams, rains, and winds, etc. He indicated the effects of the alternate sinking and raising of strata through earth shrinkings and volcanic phenomena, and taught that purely physical causes can be found for every geological effect. Playfair's "Illustrations of the Huttonian Theory of the Earth" augmented the teachings of Hutton's book, while works by Jameson, Kirwan, Boué, Sir James Hall, Daubrée, St. Claire-Deville, Buckland, Sedgwick, Bakewell, Breislak, Maclure, and others rapidly appeared sustaining the Huttonian, or the Wernerean theories of geological deposition. The work of James Sowerby (1757-1822), entitled "The Mineral Conchology of Great Britain" and that of James de Carle Sowerby (1781-1871), published between 1812 and 1845, marked the establishment of paleontology as a science. Both father and son were well-trained naturalists and artists, and, like William Smith, reproduced the fossils and their containing rocks to scale and in natural colors. These works greatly simplified the labors of field geologists in identifying rock strata and type fossils. In Germany geology was worked out by Baron von Schlotheim (1764-1882), Goldfuss (1782-1848), and Count Munster (1776-1844). Brocchi (1772-1826) described Italian fossil strata. The "Geological Classification of Rocks," of MacCulloch, marked the separation of petrology as a science from descriptive geology. MacCulloch noted that the ancient granites and granite schists are among the oldest rock forms. Von Humboldt, Murchison, Lyell, De la Beche, Von Buch, Elie de Beaumont, Holley, Geikie, Bonney, Wollaston, Scrope and Daubeny were among the pioneer geologists in Europe, while James Dwight Dana (1818-1895), E. S. Dana, Conrad, Hitchcock, Warren, Lesley, Fremont, and others published descriptive geological accounts in the United States. References to the geology and minerals of New Mexico were made in Humboldt's "New Spain." Greenhow's work on Oregon and California, published in 1845, and Lewis and Clark's reports added much to our knowledge of American topography and geology. These reports were followed by those of Stanton, Clarence King, Hague, Emmons, Custer, Powell, Davis, Gilbert, Agassiz, and others which dealt with various phases of American geology, paleontology, glaciation, and mineralogy, and prepared the way for the publication of the valuable works of Dana, Williams, Iddings, Washington, Pirsson, Clarke, Grabau, Brush, and others. The treatment of geological problems from the viewpoint of present causes was begun after the publication of Lyell's "Principles of Geology" (1830-1833). Earlier geologists were aware of the fact that many of the rock formations had been derived from other consolidation of sand and mud beds and by other actions which may be studied in operation to-day. But the systematic manner in which Lyell treated the whole field of geology made such an impression upon geologists that the publication of his great work marked a new era in the science. De la Beche, Buckland, Geikie, Bonney, and other geologists in England; Dana, and a number of scientists in the United States Geological Survey, in America; Vogt and Naumann, in Germany; Studer in Switzerland; Stopanni, in Italy, and many specialists in other countries took up the work of Lyell, and at present practically every important geological factor is known and the effects of its operations have been described. The succession of life in geological periods is studied under paleontology. This science developed at the same time as systematic and descriptive geology. Many great naturalists have contributed to it. Agassiz, Hall, Dawson, Walcott, Marsh, and others in the United States and Canada; Owen, Prestwich, and others in England; and numerous writers in Europe have published valuable monographs on various phases of fossil and strata-graphical geology. Paleontology, by fixing the succession of animal and vegetable eras, has served as a basis for measuring time, revealing the antiquity of man and of the principal mammals, as well as showing changes in climate, and in land and sea areas. The application of geology to many industries called forth another branch of the science known as economic geology. This deals with the origin and geographical distribution of the useful minerals, the derivation of underground waters and petroleum, and the changes undergone by soils. The first important impetus to economic geology was given by the publication of Whitney's "Metallic Wealth of the United States" in 1854, Von Cotta's work on ore deposits in 1859, and the economic references in the textbooks of the leading European and American geologists. The recent work of Bonney, Groddeck, De Launay, Phillips, Prosepny, Van Hise, Emmons, Le Conte, Lindgren, and others has greatly advanced the interest and usefulness of the science. These writers carried out an extended series of investigations on the depth temperature and physical and chemical condition of the earth's crust. Chemical analyses of rocks and soils were made and the changes wrought by physical and chemical forces were noted. On these were based theories as to the formation of rocks, soils, minerals, and ore deposits. The erosive properties of soil water were found to be limited to a depth not exceeding 20,000 feet, although hydrostatic water bodies are rarely found as low as half that distance, the rise in temperature precluding their existence. The work of these men revealed the part played by vulcanism in rock changes, and the effects produced through hot solutions and magmatic intrusions. Various systems of classification of minerals and ore deposits were developed. Richard Beck's, "The Nature of Ore Deposits" (1900), and Lindgren's "Mineral Deposits" (1919), are works which have contributed to the systematizing of economic geology from the mineral standpoint, and the establishment of epochs of metal generation. The ore deposits of the United States have been described in the monographs of the United States Geological Survey, and by Kemp, Spurr, Grabau and other writers. This branch of geology emphasizes the strong tendency to concentration shown by mineral elements. All climatic forces are found to aid this work. Underground waters, both flowing and stationary, are powerful assistants. Other phases of economic geology have been developed in studies of subterranean waters, microscopical petrology and mineralogy, the chemical analyses of rocks, etc. Among the leaders in this work have been Pirsson, Emmons, Iddings, Washington, Van Hise, Clarke, and others. The enormous metallurgical industries of to-day are all dependent upon scientific principles chiefly discovered and applied in the nineteenth century. Metallurgists in the previous century knew that by adding certain metals to molten steel it could be hardened. A method of this kind was published by Réaumur in 1722. Tool points, he showed, could be hardened if the steel when red hot was forced into solid tin, lead, copper, silver or gold, thus producing an alloy stronger and harder than the pure steel. A series of calorimetric researches on metallic alloys, carried on by Bergman, led to the discovery that steel differs from iron merely in the carbon contents. Clouet, in 1798, followed this by an experiment in which he melted up a little crucible iron with a diamond and obtained a mass of steel. This created a sensation and led to many other experiments on the metallurgy of cast and wrought iron and steel. Thomas Young, in 1802-7, studied the mechanical properties of iron and steel and developed the theory of the modulus of elasticity. A patent was issued to the Rev. Robert Stirling, in 1817, for a regenerative iron smelting furnace. The next year Samuel Baldwin Rogers substituted iron bottoms for sand bottoms in puddling furnaces. Faraday and Stodart produced the first alloy of nickel and steel in 1820, and in 1822 Faraday showed that there is a fundamental chemical difference between hard and soft steel. The first patent for a hot blast for iron furnaces was granted to James Beaumont Neilson in 1828. All these discoveries led to important improvements in iron making. The steam hammer was patented by Nasmyth in 1842, and between 1843 and 1848 Thomas Andrews conducted valuable investigations into the heat of combination. The ground was now prepared for one of the greatest of metallurgical inventions--the conversion of pig iron into steel by an air blast in a Bessemer converter. This invention not only vastly extended the use of steel, but drew attention to the valuable oxidizing effects of a hot air blast and in that way induced many important improvements in the metallurgy of copper, lead, and zinc. Siemens, Whitworth, Bell, Graham, Percy, Richards, Martin, Thomas, Holley, Hewitt, Fritz, Howe, Jones, and others made further important improvements in the metallurgy of iron and steel in the United States and Europe. One of the early American iron smelters was built by Governor Keith, in 1726, in New Castle County, Delaware. A rolling mill and forge were subsequently built at Wilmington. The first American smelted iron was shipped to England from smelters in Maryland and Virginia in 1718. The Bessemer steel process was introduced into the United States by Abram Hewitt at the Troy smelter, New York, in 1865. From these beginnings the iron industries of the United States have grown so that they now produce more than two-fifths of the world's annual supplies. The alloys of iron and steel have now attained importance and a new science known as metallography has developed. Professor Arnold, of Sheffield, Sherard Cowper-Coles, Roberts-Austen, Sorby, Tschermak, Tschernoff, Wüst, and Ziegler have been active promoters of this branch of metallurgy, and a closely related one dealing with the effects of the heat treatment of metals. Developments in the iron industries led to others in the metallurgy of copper, lead, and zinc. The application of the blast furnace to copper, lead, and zinc smelting was chiefly made in America. One of the early furnaces was built in Leadville, Colorado, in 1877. From that time, pyritic smelting has been chiefly developed by American metallurgists. The metallurgy of lead, copper, and zinc has reached a similar high plane to that attained by iron and steel. The metallurgy of gold and silver began to improve after the discovery of the Californian deposits in 1848. The stamper battery and amalgamation processes were improved; when sulphide ores were encountered, chlorination processes were developed. Subsequently, in response to demand for a cheaper chemical solvent for low-grade ores, the cyanide and bromide processes were devised. The application of the electric furnace to metallurgy greatly increased the scope of metallurgists' methods. Pichon, in 1853, described a small arc furnace with which he was experimenting, and in 1878 Sir William Siemens built a furnace for reducing iron ores. Moissan made numerous tests of furnaces and smelting methods in the nineties and did much to develop commercial electric smelting. Faure, Cowles, Borchers, De Chalmont, Girod, Heroult, and others invented furnaces, smelting methods, and metallurgical processes. The aluminum, carborundum, acetylene, and other important industries are developments from the electrometallurgy of iron and copper. Zinc, copper, nickel, silver, gold, and platinum plating and the electrodepositing of copper in the form of tubes by the Elmore process are dependent upon the principles of electrometallurgy as is the electrorefining of metals. [Illustration: Copyright, Keystone View Co. EDOUARD BELIN AND THE TELAUTOGRAPH, WHICH TRANSMITS PICTURES BY WIRE] [Illustration: LEE DE FOREST, INVENTOR OF THE OSCILLATING AUDION] [Illustration: AUTOMOBILE WITH RADIO EQUIPMENT FOR LISTENING IN EN TOUR] The physical phenomena of the earth's atmosphere are studied under the science of meteorology. The art of weather forecasting is as old almost as mankind, but only in recent years has it been placed upon a sound basis. Torricelli, in 1643, invented the barometer; Boyle, in 1685, developed it and applied it to measuring gas pressures. The chemists of the eighteenth century, Boyle, Black, Rutherford, Priestley, Scheele, Lavoisier, and Cavendish, all studied the chemistry of the atmosphere. Franklin, in 1749, raised thermometers by kites to measure temperatures. Balloon ascents were made by Jefferies and Blanchard, in 1784, for atmospheric observations. Soundings of the upper air by balloons, kites, and other apparatus have been conducted since the closing years of the nineteenth century. CHAPTER XV MEDICINE AND PHARMACY Medicine was in a state of transition at the beginning of the nineteenth century. The great scientific discoveries of the eighteenth century had carried people away to such an extent that they showed a tendency to exaggerate their bearings upon medicine. The result was a wild diffusion of extravagant speculation and unsubstantial hypotheses. One of the leading physicians of the eighteenth century, who wielded broad influence throughout Europe, was Herman Boerhaave (1668-1738). His work, entitled "Aphorismi," published in Leyden, 1709, was immensely popular. It was translated into all the European and several Asiatic languages. His reputation now depends upon his chemical discoveries and his medical teachings. One of the most brilliant students of Boerhaave's medical school was Albrecht von Haller (1708-77). Haller published many medical works and monographs. His "Elements of Human Physiology," (1759-66) is the best known. The function of bile in the digestion of fats, the demonstration of Glisson's hypothesis that irritability in an excised muscle is a specific property of all living tissues, and several theories explaining the heart's activities, were among his best contributions to medical science. The discovery of the existence of lacteal and lymphatic vessels in birds, reptiles, and fish brought William Hewson into prominence and secured him membership in the Royal Society. He published his monograph on the coagulation of the blood in 1771. William Cumberland Cruikshank (1745-1800) investigated the surgery of the nerves, the functioning of the Fallopian tubes, the physiology of absorption. The electrical discoveries of Galvani, Volta, Benjamin Franklin, Henly and others caused much experimenting with the electric current in the treatment of muscular diseases. The Monros, father, son and grandson, by their wonderful teaching abilities, caused the medical teaching center of Europe to be transferred from Leyden to Edinburgh in 1720. These men, and many of their students, did brilliant work in all branches of medicine. The medical school which they so established in Edinburgh University still maintains its great reputation. The best anatomists of the eighteenth century were Cheselden, Pott, the Monros, the Hunters, Desault, and Scarpa. Their work was largely topographical. Surgical anatomy started with the writings of Joseph Lieutaud (1703-1780), Albinus, Eisenmann, Soemmering, Mascagni, Sandifort, and Caldani. The anatomical textbooks in use in the year 1800 gave general accounts of the body's structure and included current theories of the functions of organs and their relationships to injuries and disease. More than half of the chapters were occupied with morbid anatomy and the recital of cases. The anatomy of the tissues and finer structures was neglected because the microscopes of the period were little better than simple lenses. Physiology was studied by all medical students, but the science was so badly developed that it never stood alone. For many years it formed a part of studies in anatomy. Early in the nineteenth century it began to expand, and in 1846 physiology was taught as a separate subject for the first time at Guy's hospital, London, by Sir William Gull. Before that it was taught by the professors of midwifery. It was the great developments made in chemistry and physics, referred to in previous chapters, that pushed physiology to the front as an important branch of medical science. Denman's "Introduction to the Practice of Midwifery," the work of the greatest living authority at the time of its publication in 1805, shows that gynecology hardly existed at that time. Anesthetics and antiseptics, together with the systematic employment of abdominal and bimanual palpation, all were revolutionary discoveries of the nineteenth century, unknown when Denman presided over the obstetric department of the Middlesex Hospital. When the nineteenth century opened, medical men were unaware of the value of auscultation and percussion. They were familiar with the symptoms of fevers and with diseases of the heart and chest, but they had no means of determining differences between them. Textbooks of that time show that the now common forms of heart disease were known only from post-mortem inspections. But they distinctly state that physicians were unable to determine, in case of changes in stricture of the heart's valves, what part was affected. The seat of disease in heart and chest troubles could not be located. Parasitology was no better advanced. Books published as late as 1810 indicated that parasites, like hydatids, threadworms, etc., were very puzzling phenomena to the physician. The status of surgery throughout the eighteenth century was very low. The best work was done in France and Holland, until Cheselden, the Hunters, the Monros, and Abernethy established their schools in England and Scotland. German medical practitioners were barbers until after the army authorities formed the Medico-Chirurgical Pépinière in Berlin in 1785. There were several good medical schools in the United States in 1800 including those of the King's College, New York, and of the Harvard, Dartmouth, and Philadelphia Colleges, and the University of Pennsylvania. There were also numerous medical societies. European medical and surgical textbooks were used like those of Cheselden, Monro, Haller, Boerhaave and Sydenham. Medical practice was on the same plane in America as in Europe. There were many patent remedies used, but the authorities recognized the importance of regulating the practice of medicine. Regulation acts were passed in New York City in 1760, New Jersey in 1772, and a general quarantine act was enacted by Congress in 1799. The modernization of medicine was brought about to a large extent by the publication of the "Conservation of Energy" by Helmholtz, in 1847, and Darwin's "Origin of Species," in 1859. These books cleared away completely the myths and legends which had surrounded medicine at earlier periods, and taught medical students the strict need of proceeding entirely upon scientific grounds precisely as chemists, physicists, engineers, and others were already doing with wonderful success. Darwin's biological teachings appealed very strongly to medical men and influenced all their activities. Virchow's "Cellular Pathology," published in 1858, Huxley's textbooks on "Physiology" (1866) and on "Vertebrate and Invertebrate Anatomy" (1871-77) Haeckel's "General Morphology" (1866), and numerous medical encyclopedias and textbooks on practice and special diseases were the result of the new scientific spirit. New medical associations were formed and these promoted discussions, the reporting of observations, and the publication of innumerable monographs. Medical journals and magazines of a high character did fine educational work. The investigations on fermentation and putrefaction made in France by Pasteur caused Joseph Lister, professor of surgery at Glasgow University, to reflect upon the great mortality witnessed daily in the hospitals from pyæmia, erysipelas, tetanus, septicemia, gangrene, and other similar diseases. He observed that in spite of his great care to maintain scrupulous cleanliness in treating wounds, 45 per cent of his surgical cases were mortal. Pasteur's dictum that putrefaction is a micro-organic phenomenon, caused Lister to experiment with the view of preventing the development of microorganisms in wounds. Beginning with weak solutions of zinc chloride and zinc sulphite, he accidentally tried carbolic acid, securing surprising results, and two years later, in 1867, he published his monograph on antiseptic surgery which instantly became world-famous. Lister, instead of being carried away by the celebrity he attained, turned his attention to the scientific development of his important discovery. He investigated lactic-acid fermentation, the relation of bacteria to flesh inflammations and to the best methods of treating wounds antiseptically. Lister, however, was not the first to employ antiseptics in the treatment of wounds, and his great contribution to medical practice was due to the systematic manner in which he experimented. He was not a brilliant surgeon, but a deliberate and careful one whose chief desire was to have the patient recover. His whole surgical career was guided by this principle which proved so successful that before his death the whole medical profession saluted him as master, and when he died, rejoiced that his remains were entombed in Westminster Abbey. Theodor Billroth was one of Lister's greatest disciples. He introduced Lister's methods into continental surgery and through their use improved the treatment of wounds and opened up new fields in the surgery of the alimentary tract. He was the first to make a resection of the esophagus and pylorus and to excise the larynx. Mikulicz-Rodecki, a Pole, was Billroth's chief assistant. He was also a pioneer in Lister's practice. Specializing on the surgery of the alimentary organs, he promoted antiseptic methods and introduced the modern modes of exploring the esophagus and stomach. He was also a master in the treatment of diseases of the mouth. Felix Guyon applied Lister's system to surgical treatment of the genitourinary ailments, and became a leader in this class of surgery. Bernard Naunyn, a well-known German writer on surgery, became a leading authority on diabetes and diseases of the liver and pancreas. Jean Martin Charcot made the Salpêtrière Hospital, Paris, the greatest of the world's neurological clinics. He was also a great authority on diseases of the biliary passages and kidneys. Sir James Paget, Sir Jonathan Hutchinson, Sir William Gull, Jenner, Wilks, Spencer Wells, and Clifford Allbutt, besides doing much by their writings to advance the practice of medicine, all closely allied themselves with large hospitals, giving as much attention to the hospitals as to the treatment of disease. Modern hospitals are largely due to their pioneering work. Louis Pasteur's studies in fermentation led to the discovery of lactic-acid bacteria and this was the starting point for a number of revolutionary discoveries in bacterial diseases. Infectious diseases were placed in new categories by his work. The etiology of traumatic infectious diseases was advanced by the researches of Robert Koch (1843-1910). His work in discovering the cholera vibrio, the microorganisms of Oriental ophthalmia and his researches on the nature and treatment of tuberculosis, made his name known everywhere. His isolation of the tuberculosis germ in 1882, and that of Asiatic cholera in 1884, were leading steps toward the discovery of a great number of disease germs. Fevers, like typhus, typhoid, yellow fever, and malaria, a few generations ago, took a great annual toll of lives. The work of the men mentioned above, Lister, Pasteur, Koch, and the French physiologist, Claude Bernard, gave medical men the means of curbing the ravages of these diseases so that to-day they are incidental annoyances rather than human scourges. The germ of typhoid fever was discovered in 1880 by Eberth. The cocci of pneumonia were isolated by Frankel in 1886. Modern surgery has been greatly facilitated by the employment of numerous anesthetics, chemicals which possess the power of inducing local or general insensibility. Soporific drugs have been used in surgical operations since the remotest antiquity, but modern practices in the employment of anesthetics followed the discoveries of Faraday in 1818. He described the properties of nitrous oxide, or ether and other gases in that year and suggested their use in medicine. John Godman (1822), James Jackson (1833), and Drs. Wood and Bache (1834) were among American medical men who made use of Faraday's suggestions. Dr. Horace Wells, a dentist at Hartford, Connecticut, used ether in 1844. Two years later W. T. Morton, a dentist in Boston, employed it successfully. Chloroform was described as a useful anesthetic by Dr. Flourens, of Paris, in 1847, the year in which Sir James Simpson introduced ether as an anesthetic in obstetric practice. Mesmer introduced hypnosis into medical practice about 1777, and in 1784 Benjamin Franklin reported favorably on the medical value of what he called magnetic sleep. Alexandre Bertrand, about 1831, described the nature of hypnosis and in 1841 James Braid employed it in his English medical practice. The employment of hypnosis has not become general, although it is recognized that in certain nervous troubles there is a field for it. Among other American medical men who advanced their science in the past were James Marion Sims (1813-1883) and Thomas Emmet, who acquired wide fame for successful methods of operating in obstetric diseases. William Beaumont (1785-1853) investigated the offices of the gastric juice and devised treatment for digestive troubles. John Shaw Billings served his profession by compiling, with the assistance of Robert Fletcher, an Index Catalogue of the Surgeon General's library, Washington. Pharmacology is as old as medicine. The medicinal qualities of herbs, roots, and gums were known to primitive man. There have been herbalists and druggists in all important communities at all times. Scientific pharmacology, however, is just as new as modern medicine. Cordus published a pharmacopœia, which listed drugs in use in 1535. Since that time many such works have appeared. The second of the Monros of Edinburgh University Medical School, Magendie, and Claude Bernard placed pharmacy upon a scientific basis. They followed scientific methods used by Fontana in Florence in 1765 in studying the effects of snake poisons. Pareira's "Elements of Materia Medica" was the leading textbook in 1842. This work gave very brief accounts of the physiological effects of drugs. The physiological values were not properly appreciated until about twenty years later. Drugs are now scientifically classified and prepared, the full resources of science being used in their manufacture. American chemists have invented machinery and methods of preparing new drugs. Citrate of magnesia was invented by Henry Blair, of Philadelphia. Many other valuable remedies came from his laboratory, including sirup of phosphates. CHAPTER XVI ELECTRICITY AND RADIOACTIVITIES Among the most marvelous scientific developments of the nineteenth century those in the electrical field claim universal attention. It was only as recently as 1844 that Morse introduced electric telegraphy. The telephone was introduced by Alexander Graham Bell in 1876 and Edison built one of his early dynamos in 1878 and in 1879 made his first high resistance incandescent lamp for parallel operation. The first Edison power and lighting station was opened at 257 Pearl Street, New York City, in 1882. Although electrical phenomena were understood in a general way thousands of years ago, they were not studied and applied to practical purposes until the sixteenth century when William Gilbert carried out his classical experiments in the reign of Queen Elizabeth. The Leyden jar was discovered in the early half of the eighteenth century. From experiments carried out with these jars a great number of important inventions were derived and our knowledge of electricity was for many years dependent upon researches of this kind. Benjamin Franklin in experimenting with the Leyden jar found that its electrical discharges were similar to those of lightning and he subsequently discovered that the inner part of the jar, when charged with a frictional current, was positively electrical while the outer portion was negative. The voltaic pile was invented in 1796 as a result of Galvani's experiments in physiological electricity and Sir Humphry Davy exhibited the first practical electrical lamp before the Royal Society in 1809. The dynamo was, in substance, invented by Faraday, and described by him before the Royal Society in 1831. This was, perhaps, the greatest of all electrical triumphs because it gave engineers a practical means of generating and using electrical currents of any desired dimensions. Bunsen in 1840 devised a means for making carbon rods for arc lamps, and Edison made practical carbon incandescent lamp filaments in 1879. Faraday's invention promoted all of these lighting discoveries. The engine-driven electric dynamo was made a practical machine in 1870 and thenceforward became the source of power of a great multitude of secondary machines, such as electric street cars, marine engines, power plants, and forging hammers. A new and profitable field was opened for the use of electricity by the invention of the electric furnace. Sir Humphry Davy produced his electric arc in 1808 and was greatly impressed with its fusing properties. He melted many metals with the arc and found that it fused platinum just as easily as an ordinary tallow candle melts beeswax. The electric furnace, which is now extensively used in chemical and metallurgical works, is simply a large electric arc provided with means for containing the heat. Furnaces lined with carbon are now heated to over 4,000 degrees centigrade. When the electrical manufacture of aluminum on a large scale was started at Niagara, Dr. Edward Acheson, who was impressed by the industrial needs of cheap abrasives, accidentally discovered that by heating a piece of porcelain to a high temperature in an electric furnace and bringing it in contact with pure carbon, the carbon was rendered very hard. In 1891 he carried on experiments with high currents and a mixture of ground coke and sand. He found a method of fusing these so that the oxygen of the sand passed off with carbon in the form of carbonic acid gas, and the reduced metallic silicon combined with an equal atomic weight of carbon and produced a new body which he named carborundum. The success met with in making carborundum led to the devising of a method of manufacturing artificial graphite in the electric furnace. A soft, non-coalescing graphite was made in 1906. This is extensively used in lubricating heavy machinery. Dr. Acheson produced the first chemically pure artificial carbon in his electric furnace in 1911. By using pressure during consolidation this carbon may eventually be converted into diamonds. Another valuable product of the electric furnace, acetylene gas, was discovered in Dublin by Edmund Davy in 1836. Subsequently numerous chemists discovered means for making carbides. T. Sterry Hunt, an American chemist, observed in 1886 that oxides of the alkaline metals and of calcium, magnesium, aluminum, silicon, and boron could be reduced in the electric furnace in the presence of carbon and could be alloyed with other metals. He also found that silicon and acetylene could be made that way. T. L. Wilson, a Canadian engineer, in attempting to make aluminum bronze in an electric furnace, devised an experiment for reducing lime with carbon. He found that this produced calcium carbide and secured a patent for the invention in 1892. Variations of this process are now used for manufacturing nitrogen and nitrates from atmospheric nitrogen. Wireless developments have resulted from the work of many separate investigators. K. A. Steenheil in 1838 used the earth return in live telegraphy and suggested the possibility of wireless telegraphy. Joseph Henry produced the first high-frequency oscillations in America in 1840. Lord Kelvin in 1853 enunciated the mathematical principles governing uncoupled electrical oscillatory circuits. Joseph Heyworth patented a wireless telegraphic process in 1862. Clark Maxwell in 1867 predicted the existence of electromagnetic radiations and these were demonstrated by Hertz in 1887. Hughes discovered the phenomena of the coherer and Branby used Hughes's coherer for wireless wave detection in 1892. A. E. Dolbear secured United States patents for a system of wireless telegraphy using aerials in 1886. Sir Oliver Lodge described his wireless system before the Royal Society in 1894 and in the same year Popoff issued descriptions of his wireless system. Wireless telegraphy became commercially practicable in 1897 when G. Marconi secured the promotion of the Wireless Telegraph and Signal Company in England. Marconi succeeded in turning to commercial account a long series of brilliant discoveries in electricity, and this success has led to numerous kindred discoveries. De Forest's three-electrode thermionic detector, known as an Audion, invented in 1907 and improved in 1911 by Lieben and Reiss, in 1913 by Meisser and in 1914 by Langmuir, opened up great possibilities for sound transmission by wireless telephony. The electric deposition and refining of metals have been referred to in previous chapters. Many industries are based upon these. Niepce produced commercially successful photographs in 1838. Earlier, in 1824, he had etched plates for printing and in that year published his photo-engraving of Cardinal d'Amboise. Fox Talbot patented a mixture of gelatine and bichromate of potash to take the place of the bitumen used by Niepce as a plate coating. Gillot found in 1872 that Fox Talbot's method of making intaglio plates could also be used for making relief blocks. In 1885-1886, F. E. Ives sealed two single-line screws together and made a new fine cross-line screen, which resulted in the development of the half-tone process. Ives at this time also developed the three-color photo-engraving process. Photography and photo-engraving are so widely used and are so intimately connected with our civilization that few people now realize that the great industries based upon them are the results of a few scientific discoveries of a couple of American and European scientists made only a generation or two ago. [Illustration: GIFTS FOR TUTANKHAMEN BROUGHT BY HUY, VICEROY OF ETHIOPIA. THE MAN IN THE GAY COSTUME, AT THE RIGHT, MAY BE A PHŒNICIAN. (EGYPTIAN PAINTING)] [Illustration: TUTANKHAMEN'S TOMB--BRINGING UP THE HATHOR COUCH. THE COW WAS SACRED TO ISIS OR HATHOR OF WHOM THE HORNS WITH THE MOON DISK WERE EMBLEMS] [Illustration: QUEEN NEFERTITI, MOTHER-IN-LAW OF TUTANKHAMEN This wonderful work of an unknown Egyptian sculptor represents the wife of Ahknaton, the "heretic" king of Egypt (originally Amenhotep or Amenophis IV). The original is now in the Berlin Museum.] Chemists had long recognized the fact that certain chemicals like preparations of zinc, fluorine, and phosphorus were phosphorescent. It was found early in the eighties that Welsbach gas mantles, when placed on a photographic plate and exposed in a dark room for two weeks, made a fine picture. Invisible rays in the mantle imprint its image. Röntgen, in 1895, discovered what are now known as the X-rays. This discovery was the result of experiments begun in 1859 by Plucker to ascertain the cause of fluorescence in light glass, and Sir William Crookes, between 1879 and 1885, carried out beautiful experiments on fluorescence. These were the immediate pioneers of the discovery of the cathode rays and the other great radio discoveries of recent years. Crookes, remembering Faraday's suggestions concerning a fourth state of matter, expressed the opinion, in 1885, that the matter constituting cathode rays is neither solid, gaseous, or liquid, but in a fourth state which transcends the gaseous condition. Perren found in 1895 that the rays carried electrically negative charges and Sir J. J. Thomson noticed that their velocities are appreciably less than the speed of light. Owing, however, to their great momentum, hardly anything can long endure their impacts. They fuse platinum and make diamonds buckle up into coke. Electrons, which constitute the cathode rays, were originally studied in Crookes vacuum tubes, though they are now found to pervade the universe. Larmor in 1897 proposed an electronic theory of magnetism. Henri Becquerel was the first to discover radioactivity. He made radiographs from uranium salts in 1896. M. and Madame Curie undertook the investigation of uranium and found that among the minerals occurring in pitchblende, or uranium ore, bismuth and barium showed radioactive properties, whereas when these metals are found in their ordinary ores they are not radioactive. This discovery led to the finding of two new metals, polonium and radium. Radium is now obtained by fractional distillation of solutions obtained from American and Australian pitchblende. Helium, one of the lightest substances known, was discovered in 1895 by Sir William Ramsay, and liquefied, at a temperature 3 degrees above absolute zero, or -270 degrees centigrade, by Onnes in 1908. Helium appears to be one of the ultimate products of the disintegration of all radioactive elements. Some of the most interesting discoveries about radioactivity are very recent. Radium prepared from uranium in 1915 was found in 1919 to have increased proportionately to the square of the time interval. The amount of radium in some preparations was found to have increased ten times in four years. The old idea of the constant fluxation of matter was thus shown to have been based upon a scientific truth. CHAPTER XVII SCIENCE IN THE TWENTIETH CENTURY It is obvious that we are now in a great period of transition. Scientific discoveries came so quickly at the end of the last century that a recasting and readjusting of scientific conceptions had to be undertaken. This process was in progress when the World War began. The world-wide disturbance led to temporary scientific infertility except in such directions as served the purposes of war. But therein science became allied more closely than ever before with certain branches of industry, and the cooperation thus established has been recognized in all civilized countries as of the utmost value to the future progress of mankind. The philosophic thought of each era generally develops in harmony with social and intellectual conditions. The philosophical doctrines of the leading writers may, therefore, be taken as representative of the spirit of their age. When Darwin in the middle of the last century published his doctrines of evolution, of the struggle for existence and the influences of living conditions upon survival of species, philosophy turned away from the utilitarianism and tolerance of Hamilton, Hume, and Mill and the positivism of the French to the synthetic evolutionism of Herbert Spencer. One of the basic teachings of Spencer was the relativity of knowledge. The process of thinking involves relation, difference, and likeness. This is merely relationing. Therefore no thought can ever express more than relations. The primary act of thought through which we discover likeness and difference underlies all our knowledge. A reaction against this new empiricism began in 1898, when William James published his "Philosophical Conceptions and Practical Results." This work popularized the philosophy of pragmatism which denies the absoluteness or ultimateness of the traditional antithesis between theory and practice and relies for its justification upon the fact that everything which we think about, and do, must first be willed. Reality consists in pure experience quite independent of thought. Bergson developed this philosophy of practicalism further and taught that knowledge of reality comes through intuition and that life is merely intuitive knowledge. Intuition, is deeper than scientific reason because it feels, and links us with, the eternal processes of nature. Philosophic thought is now temporarily influenced by the revival of an old principle known as the principle of relativity. The popular name for this is the Einstein theory, because in 1905 Albert Einstein, working on some theories developed by Lorentz and Fitzgerald, published his first principle of relativity which suggested that the velocity of light is constant, however the position of an observer may vary and that space and time are variable. In 1917 Einstein enlarged this idea in order to include all the laws of nature. Space and time are treated as just mental concepts. They lack the concreteness of matter, but they compose the framing of the universe and give it form and continuity. Consequently we see so much of them that we attribute reality to them. The theory of relativity suggests that time is not continuous. There is no identity of instants at different places. The present instant really does not extend beyond this immediate point. At other points there are instants older, younger, and contemporaneous with this instant. They are, however, quite distinct from this one. In order for an instant to be simultaneous it would be necessary that it should occur at the same point. An object or event gains its substance and form from activities of our minds. Any meaning or significance that an object or event has is also derived from our minds. The reality of the universe is an activity, or series of activities, which are manifested in life and mind. The relativity of space is illustrated by an example given by Professor Henri Poincaré. Assume that I meet you in Wall Street, New York, and say, "I will meet you here again at this time to-morrow." You promise to do so. But you could not keep such a promise except with regard to position on the surface of the earth, because between now and to-morrow the earth will have moved over an enormous distance carrying Wall Street and a great mass of other things with it. The sun also will have moved away the stars, carrying the earth with it. Another interesting mental picture is drawn by Professor Herbert Wildon Carr to illustrate the philosophical meaning of the principle of relativity. Suppose that on a very frosty morning we were to see a watery vapor in the air we breathe condense into a little cloud and after floating around a while gradually disappear and become reabsorbed in the atmosphere. Assume that at the moment of this reabsorption we should undergo an instantaneous transformation of all our proportions so that our new dimensions become infinitesimal in comparison with our former state. Do you think that we would recognize the fact that we had changed? The theory of relativity declares that we would not know what had happened, because with the alteration in proportions the ratios would remain constant. The change would express itself in the new dimensions of objects around us. The little globules of water composing the little cloud would now appear like stars and planets occupying immense areas in distant spaces, far apart from each other, and all undergoing a slow age-long evolution. Such a change would be signalized as a new time and a new space. Yet the principle of relativity does not appear to our physical senses to represent a truth of nature. It is noteworthy that the principle of relativity is usually invoked when conditions are unstable, when thought is confused, and when a period of readjustment is in progress. Thus the Einstein theory may be representative of present-day harmonies, but yet may prove, in the future, to have been merely a passing philosophic mood. Bagehot, a shrewd observer, writing in 1868 about the changes wrought by Darwin's evolutionary theory, said: "There is scarcely a department of science or art which is the same, or at all the same, as it was fifty years ago. A new world of inventions has grown up around us which we cannot help seeing; a new world of ideas is in the air, and affects us though we do not see it." Those were very true words more than half a century ago, yet they serve to describe present conditions! GENERAL INDEX A, vowel sound, record of, iv, 234 Aard-vark, xii, 281-2 Abacus, or calculating machines, xv, 183-4, xvi, 61 Abalones, xii, 71 Abbe, Prof. Cleveland, i, 216-17 Abbot, Dr., solar studies, ii, 171, 186-7 Abdomen, blood circulation in, ix, 196, 197; methods of examination, x, 147, 371; muscles of, ix, 77 Abdominal Organs, control of circulation of, ix, 215, 216, 217, 220; development of, in black and white races, xv, 50; mesentery support of, ix, 59; smooth muscles in, 160-1 Aberration of Light, ii, 91-2 Abert, Lake, Oregon, xiv, 203 Abnormal Complexes, x, 355-6 Absaroka Range, xiv, 104-5, 226 Abscesses, cause (germs) of, x, 195, 198, 221; cure of neurasthenic, 58-9 Absinthe, source, xiii, 266 Absolute, technical meaning, iv, 381 Absolute Magnitude (stars), ii, 317; Adams' method of determining, 124, 153; spectral type and, 115, 317; used in measuring star distances, 318, 330 Absolute Maximum & Minimum (meteorology), i, 204, 365 Absolute Scale (thermometry), i, 73, iv, 141, viii, 107-8 Absolute Units, iv, 64, 69, 70 Absolute Zero, i, 73, iv, 141, v, 347-8, viii, 107-8; molecular condition at, iv, 142-3, viii, 108; nearest approach, i, 32, iv, 173, xvi, 194; of outer space, vi, 270 Absorption Lines, ii, 111-12 (see Fraunhofer Lines, Spectrum) Abstract Ideas, difficulty of attention to, xi, 228, 233-4; expression of, in primitive language, xv, 144-150 Abul Wefa, Arab astronomer, ii, 38 Acceleration, definition & measurement, iv, 57, 381; force in relation to 59-61, 63-4, 71-2; of gravity, 65 Accidents, from electricity, x, 254; from fatigue, xi, 274; prevention of, vii, 32-3, xi, 365 Accidents (geological), xiv, 188 Accommodation, of vision, ix, 110-11, 113; muscles of, 161, 162 Accumulators, storage batteries, iv, 300 Accumulators, water-pressure, v, 106 Accuracy, habit and, xi, 253; indifferent types of men, 156, 157, 158-9 Acetic Acid, vi, 111, viii, 220; solubility, 112; in vinegar, 218, 249, 293 Acetylene Gas, discovery, xvi, 190; formation, vii, 312; in steel making, 321; luminosity of flame, viii, 60; preparation & uses, 231 Achenes, xiii, 58-9, 344, 345 Acheson, Dr. Edward G., vii, 300-1, 309-10, xvi, 189-90 Acheulean Implements, xv, 105, 107 Achromatic Lenses, iv, 373; invention, xvi, 125-6 Achromatic Refractors, ii, 100-1, 103 Acidosis, x, 280 Acids, viii, 19-20, 114-15, 373; action on saccharides, 226, 228; amino, 230 (see Amino Acids); bases and, 115; defined by ionization theory, 122; electrolytes, 125; formation, 20, 39, 118, 373; formation in body, x, 280-1; hydrogen prepared from, viii, 32-3, 102; ionization in solution, 119-25, 300-1; manufacture of, 275-6; molecular structure, 218; molecular structure & physical state, 298; nomenclature, viii, 98; organic, 52, 219-21; oxygen in, 34; salts formed from, 72, 83, 114, 373; vegetable, 222-3, 336, 349; volumetric analysis of, 292-3 Acid Salts, viii, 116 Acne, causes of, x, 201, 311 Aconite, xiii, 252 Acorns, xiii, 193; dispersal by squirrels, 55-6, 340; survival rate, xv, 21 Acoustic Clouds, i, 190 Acoustics, atmospheric, i, 186-96; of auditoriums, iv, 239 (see also Sound) Acquaintanceships, selection of, xi, 257, 380-1 Acquired Characters, inheritance of, ix, 325-7, x, 230 Acquired Tastes, xi, 72-3 Actinic Rays, iv, 365-6, 381, vii, 250, 361 Actinolite, iii, 321-2 Action & Reaction, iv, 33-4, v, 143; Newton's law, ii, 66, iv, 69 Activity, food needs dependent on, ix, 295, 296, 297; mind as, xi, 12, 13, 236; temperature effects on, i, 323-4 Activity (mechanics), iv, 80 Adaptations, of eardrum to sound, xi, 100; of eye to colors, 95; of nose to odors, 80-1; of skin to pressures, 111; of tongue to tastes, 72; to warmth and cold, 113 Adaptation to Environment, xv, 16; by animals, 16-18; by man, 3, 25, 26, 28, 31, 36; by plants, xiii, 11, 12, 28-31, 89-90, 149-50, 346, 355-83, xv, 16, 18-19; between insects & plants, xiii, 144, xvi, 152-3; mental efforts at, x, 361-2; natural selection and, xv, 24-5; principle never perfect, xvi, 152-3 (see also Environment, Environmental Variation) Adder's Tongue Fern, xiii, 159 Adding Machines, v, 326-7 Addison, Thomas, x, 106, 112 Adenoids, ix, 104, 224, x, 341-2; as infection foci, 220 Adenoid Tissue, ix, 223, 224 Ader, C., v, 231 Adiabatic Changes, iv, 158-9, 381 Adipose Tissues, ix, 298 Adirondack Mountains, age, iii, 191; club mosses in, xiii, 305; erratic bowlders in, iii, 70; fault blocks in, 89; fault lines and streams, xiv, 128; granite formation, iii, 112; Grenville strata, 165, 167; ice age survivals, xiii, 321; iron district, iii, 359; lakes, how formed, 145; lightning effects, 24; Ordovician strata eroded, iii, 186; quartz & slate formations, xvi, 29 Adjutant Bird, xii, 255 Admiration, sentiment of, xi, 146-7 Adolescence, mental conditions of, x, 236-7 Adrenalin, ix, 171-2, 209, 219, xi, 137, 138, 273 Adrenals, ix, 170-1; Addison's disease of, x, 112-13; functions, xi, 60, 137; shock effects, 59 Adriatic Sea, bora, i, 133; coasts of, xiv, 252-3, 263; filling in by deltas, 53; Karst district, 150 Adsorption, viii, 316, 373 Adulteration of Food, viii, 370-1 Adults, basal metabolism in, x, 271; growth in, ix, 287, 288-9; heart rate in, x, 334; protein needs of, ix, 281-3 Advance Metal, resistance, vi, 77 Advertising, psychology of, xi, 343-9; sign & display, vii, 339-43; tied images in, xi, 221; weather considerations, i, 255-6 Ægean Sea, volcanoes, xiv, 317, 319 Æolian Tones i, 195 Aerial Echoes, i, 190, 193 Aerial Roots, xiii, 20-2; of fig tree, (illus.), 48 Aerials, iv, 314, vii, 261; Dolbear's patent, xvi, 191; in aeroplane sets, vii, 282 (see also Antennæ) Aeroclinoscope, i, 282, 365 Aerology, i, 18-19, 20-3, 89, 365-6 Aeronautical Meteorology, i, 284-305 Aeronautics, accidents & safety questions, i, 49-50; accidents in World War, x, 246; aneroid barometer importance in, iv, 124; fog in, i, 94, 95, 300-2; history & future, 39-51; Langley's work in, iv, 43-4; pilot balloons in, i, 22; therapeutic possibilities, 51; weather importance, 284-6; wind & air currents, 126, 130, 289-300 (see also Aeroplanes, Balloons) Aeroplanes, altitudes attained, i, 22, 46; altitude effects, 303; astronomical use, ii, 208, 212, 225-6, 382; Brocken specters seen from, i, 185; engine efficiency, v, 170; gyroscopic stabilizing, 343-4; helicopter, i, 42; history & development, 40-1, iv, 43-4, v, 230-3, 382, 383-4; landings, i, 42, 45, 294 (fig.) 302; mail service, 44-5, vii, 76; meteorological uses, i, 22; passenger, 41-2, 43-5, 50; photographic mapping by, 45-8; principles, i, 286-305, v, 233-8; propellers (tractors) of, iv, 34; radiotelephony and, vii, 282-3; rise or "taking off" of, iv, 43; safety question, i, 49-50; stereograms from, xi, 180-1; uses, present & future, i, 41-2, 43-9; war uses, v, 107, 372-3, 375; wind effects, i, 285-6, 289-300; wireless directing, vii, 283; World War, i, 185, 308, 312, vii, 283, x, 246 (see also Aeronautics, Aviators) Æsculapius, x, 16, 17; temples of, 17, xvi, 44 Æsthetic Arts, development of, xv, 297-324 Æsthetic Instinct, xvi, 47, 48 Æther of Space, vi, 118-20; constitution, vii, 368; elastic solid theory, xvi, 137; universal presence of, iv, 180-1 Æther Waves, various kinds, vi, 119, 269, vii, 249, 250, 259-61, 371 Aetius, medieval writer, x, 31 Ætna (see Etna) Affection, emotion of, xi, 147; importance, 129; seat of, ix, 200 Africa, animals of (carnivora), xii, 339, 342, 344, 345, 348, 352-3, 355, 356-7, 359, 360, 365; animals,(herbivora) xii, 302, 303, 304-5, 308, 310, 320-1, 327-8, 329; anteaters of, 281; antiquity of man in, xvi, 64; bats of, xii, 370; birds of, 249, 260, 266, 267; "bush" lands of, xiv, 378-9, 380; coasts & islands, 251-2, 263; coasts contrasted, xii, 40, xiv, 305; coffee production in, xiii, 233; crocodiles, xii, 199-200; drainage system, xiv, 190; dust haze, west coast, i, 55; elephant-trapping in, xv, 225; exploration of, xiv, 196-7; forests of, 366, 368-9, 382; fishes of, xii, 151, 154, 160, 166; former submergences, iii, 216, 235; geographical features & results, xv, 136; Gold Coast, death rate on, 50; grasslands in south, xiv, 384; health conditions, 197, 223-4; lemurs of, xii, 374, 375; lizards, 208; monkeys & apes, 379, 380, 383; palm oil, importance to, xiii, 11; plains of, xiv, 217-18; plateau of interior, 196, 221, 222; rivers, broken courses, 155; rivers, navigability of, 196; rock weathering in central, 78; rodents of, xii, 288, 289-90; rubber production, xiii, 248; salt lakes, viii, 139; short races of, xv, 38-9; sleeping sickness in, x, 167-70; smallpox superstition of natives, 285-6; snakes of, xii, 214, 226, 227-8, 231-2; timber supplies, xiv, 382; vegetables originating in, xiii, 222-7; volcanoes & lava fields, xiv, 317; yellow fever on coasts, x, 160 (see also East, North, South, West Africa) African Savages, body decoration of, xv, 256, 257-8; debtors, treatment of, 370; language changes, 155; rule of fathers among, 367 (see also Bushmen) African Sleeping Sickness, x, 167-70, 199, xiv, 197, 223, 357; chemotherapy in, x, 381; Koch's work on, 150, 169 After-Images, xi, 90-2, 220; of sun (green flash), i, 171 After-Summers, i, 362, 366 Agassiz, Lake, iii, 144, xiv, 201; plain of, 215-16 Agassiz, Louis, discoverer of Ice Age, iii, 236; on fish scales, xii, 134; on snapping turtles, 188 Agate, iii, 337 Age, chronological & physical, ix, 214; effect on disease, x, 236-7; growth in relation to, ix, 288-9 Agonic Lines, iv, 246, 247 Agoutis, xii, 289 Agramonte, Dr. Aristide, x, 160, 200 Agricultural Chemistry, viii, 334-47 (see also Fertilizers, Nitrogen, Potash, Soils) Agricultural Implements & Machinery, v, 239-50, xv, 235-6; Egyptian, xvi, 72; electricity in, vii, 230 Agricultural Meteorology, i, 245-60 Agricultural Stage, xv, 187, 199-203; polygamy in, 288; rulers in, 367 Agriculture, ancient centers of, xiii, 221; beginnings of, 209-10, xv, 200-2; civilization and, 128; fundamental importance, xiv, 218; grasslands and, 383; plains most favorable to, 218-19; possibilities, by what determined, 64; summer rain importance, 352 Ailerons, i, 289, 299, v, 238, 343 Air, amount consumed by breathing, ix, 256; ancient ideas, xvi, 79; as balloon ballast, v, 226; boiling point of, iv, 173; buoyant power of, 107, 108; burning of, in gas, viii, 55, 56; burning, in gasoline engines, v, 156-7; "change of" (vertical), i, 51; closeness or stuffiness of, (see Ventilation); combustion and, i, 10; composition, 9-16, vii, 321, viii, 66-8, ix, 254, 268; composition, discovery of, xvi, 120, 121; compressed (see Compressed Air); compressibility, v, 126; cooling power, i, 318, 319-21; critical temperature & pressure, iv, 172, 173; decay in relation to, xiii, 312-13; density of, iv, 113, 198; drying power, i, 77, 323; dryness & dampness, viii, 67, xiv, 353-4; elasticity of, iv, 198, v, 126; electrical conductivity, i, 144-5, iv, 259, 265; expansion by heat, 151; frozen, v, 345; health benefits of special types of, x, 241; heat conductivity, iv, 178, 179; ionization, i, 142-4, 146, 150; life without, (see Anaërobic); liquefaction of, iv, 171, 172; (see Liquid Air); moisture capacity, xiv, 352-4 (see also Humidity); molecular velocity in, iv, 133; necessity to life, ii, 244, 245; necessity to plants, xiii, 102, 109; physics of, historical development, iv, 28-30; popular & scientific conceptions, i, 9-10; pressure of, iv, 132 (see also Atmospheric Pressure); purifying by ozone, i, 15, vii, 354; purity tests, i, 321-2; resistance due to inertia, v, 234; resistance effects on aeroplanes, i, 286-9, iv, 43, v, 235-6; resistance to falling bodies, iv, 42, 97; resistance to projectiles, v, 369; saturated, i, 14, viii, 67; shimmering of, i, 174, iv, 328, 329; in soil, xiii, 92; solubility in water, viii, 111; sound transmission by, i, 186, iv, 195, 198-9, 201, ix, 98-9; specific heat of, iv, 161; specific heat ratio, 156; surfeit of, bodily effects, 31; ventilation of, (see Ventilation); vibrations of, 215; warming of, by sunshine, 182; warming of, by freezing water, 161; weight of, 107, 116, 124, v, 221-2, 230; weight, discovery of, iv, 29, 114-16; weight of heated, v, 223 (see also Atmosphere) Air Bladder, xii, 135-6, 164-5 Air Brakes, iv, 129, 200, v, 130-3, 380, 381; on electric cars, vii, 185-6 Air Columns, resonance of, iv, 226-31; vibrations of, 215 Air Compressors, i, 26-7, iv, 128, v, 89-93, 127-8 Air-cooled Engines, v, 160-1 Air Currents in aeronautics, i, 293-300; pilot balloons to discover, 21-2 Air Cushioning, v, 133-5 Air Holes, i, 298-9, 374, v, 224 Air Jets, v, 135-6 Airlifts, iv, 130, v, 114-15 Air Locks, v, 118-19, 124 Air Pumps, iv, 126-7 Airships, in forest service, i, 49; future landing places, 43; future uses in transportation, 42-3; high altitude effects, 303; history of development, 40-1; possibilities of, iv, 107-8 (see also Dirigible Balloons, Zeppelins) Air Springs, v, 126-38 Air Waves, i, 294 (fig.), 298 Akeley, Carl E., v, 136 Alabama, aluminum production, iii, 369; chalk deposits, 216; coal beds, 199; iron production, 358-9; soil of, xiv, 218 Alabaster, iii, 331, 332, viii, 149 Alaska, animals of, xii, 318, 319, 320, 337; auks of, 265; blackfish of, 163; coal fields, iii, 348; coast changes, earthquake of 1899, 97, xiv, 34, 114, 334-5; coast formations, iii, 57; fiord coasts, xiv, 258, 259; glaciers, iii, 59, 60, 62, xiv, 55, 60; gold production, iii, 366, 367; ice age in, 239 Albania, story of unchangeableness, v, 251 Albategnius, ii, 38 Albatross, xii, 251-2 Albe, E. Fournier d', v, 332 Albucasius of El-Zahra, x, 32 Albumens (see Proteins) Albuminuria, x, 345-6 Alcmæon, Greek anatomist, xvi, 82-3 Alcohol, (ethyl or grain), viii, 212, 213-14; boiling point, iv, 168; cooling by, 174; conversion to acetic acid, viii, 218; denatured, 250; flame of, 60; formula of, 218; freezing point of water lowered by, 299-300; frozen, v, 345; frozen in liquid air, i, 31; future motor fuel, viii, 209; manufacture, 250; per cent in distilled beverages, 250; physiological effects, ix, 94, 214, 244, 248-9, 320-1; production by fermentation, viii, 213-14, 248-50, ix, 248, x, 138; solvent properties, viii, 217; specific gravity of, iv, 112; (see also Alcohols) Alcoholic Drinks, viii, 249-50; arterial elasticity impaired by, ix, 214; food value, viii, 366, ix, 248-9; in tropics, xv, 126-7; stomach absorption increased by, ix, 244; warmth produced by, 94, 320-1 Alcoholic Fermentation, viii, 248-9; in body, ix, 248-9; Pasteur's studies, x, 138 Alcoholometer, iv, 113 Alcohols, viii, 212-14, 373; boiling points, 299; double & triple, 215; in esters, 221; molecular complexity & physical state, 298; in plants, 349; relation to ethers, aldehydes & acids, 216-18, 219; solubility, 37, 112 Aldebaran, angular diameter, ii, 151; Arabic name, 39; chemical composition, 114-15; color, 297; gaseous state, 382 Aldehydes, viii, 218, 219, 373; in sugars, 225 Alder Flies, xii, 106 Alder Trees, xiii, 193, 271-2 Aleutian Islands, blue foxes of, xii, 344; former connections, xiii, 351; volcanic nature, iii, 106, 139, xiv, 315, 316 Alexander of Tralles, x, 31, 59 Alexanderson Generators, vii, 274-5, 290-1 Alexines, of blood, x, 210-11 Alfalfa, fertilization, xiii, 138-9; in pea family, 198; nitrogen fixation by, xiv, 66 Alfonsine Tables, ii, 39, 44 Alfred the Great, language of, xv, 156; navy of, xiv, 261 Algæ, xiii, 72-3; classification work, xvi, 166; curious "showers" of, i, 358-9; fossils of, xiii, 303, 304 (illus.); found in hot springs, ii, 249, xiii, 299; in sea, xii, 16-7, xvi, 147; number of species, xiii, 323; oldest of plants, 303-4; reign of, 314, 323 Algeria, animals of, xii, 326, 359; dust storms, i, 54; record temperature, 209; snowfalls, 210 Algol, actual magnitude, ii, 321-2; secondary minimum, 328; type of variables, 325-6 Algonquin Lake, iii, 149-50 Alimentary Canal, ix, 233 (fig.); foci of infection in, x, 220; in infants, ix, 346; operation of muscles, xi, 37-8, 69; protection against germs, x, 202; sterile at birth, 201; X-ray examinations of, 373 Alimentary Disorders, x, 319-38 Aliphatic, defined, viii, 373 Alkali Industries, viii, 276-8 Alkali Metals, viii, 132-47 Alkalis, defined, viii, 373; deposits, 139; volumetric analysis, 292 Alkaloids, viii, 240 Allbutt, Clifford, xvi, 184; Osler and, x, 151; quoted, 35 Allegheny Plateau, xiv, 221; coal of, iii, 346-7; origin of present relief, 231-2 Allelomorphs, xvi, 157 Allergy, x, 216-7 Alligators, xii, 182, 196-8; savage methods of luring, xv, 222 Allotropic Forms, viii, 43, 87, 373 Alloys, viii, 272-3; aluminum, iii, 369-70; antimony in, viii, 169; copper, 164; electrolytic refinement, vii, 319-21; melting point of, iv, 161-2 Alluvial Cones, iii, 33 Alluvial Soils, xiv, 63, 70-1 Almanacs, ancient Greek & Roman, i, 67-8; Arabic word, ii, 39; weather predictions in, 243-4 (see also Nautical Almanacs) Alpenglow, i, 168, 366 Alphabet, invention & development of, xv, 175-6, xvi, 60 Alpha Centauri, magnitude, motion and type, ii, 319; parallax and distance, 312, 313, 314-15 Alpha Lyræ, drift of sun toward, ii, 18, 306; parallax, 312 Alpha Rays, i, 143, viii, 185 Alpine Glaciers, iii, 60, 62-3 Alpine Racial Group, xvi, 49-50 Alps Mountains, Alpenglow, i, 168; Arctic species in, xiv, 365-6, 377; chamois of, xii, 325; foehn wall, i, 105; forming of present, iii, 236, xiv, 233; Glacial Epoch, lakes from, iii, 146, xiv, 200; glaciers and snow line, iii, 59, 60, 62, 240, xiv, 55; goats of, xii, 326; hanging valleys and electric plants, xiv, 57; historical and economic importance, 240-2, 243, 244, 245, xv, 137-8; intense folding of, xiv, 36, 230; lakes, iii, 143-46; marine deposits, 235; massif of, xiv, 234; Napoleon's passage of, 244; passes of, 58, 240-1; population and industries, 241-2; railways and tunnels, 240-1; rainfall effects, 355; rivers of, 167; rock destruction by frost, 76; snowfall measurement, i, 118; solar heat at Davos, 210; thickness of strata in, xiv, 229; winds, i, 131-2, 133; youthfulness of, xiv, 96 Alsace, potash deposits, viii, 279, xiv, 67-8, 209 Altamira, Spain, cave pictures, iii, 305, xv, 114, 116, 118, 298 Alternating Currents, iv, 307, vi, 153, 154-5, vii, 361; ammeters for, vii, 166, 169-72; carbon arcs on, 208-9; circuit breakers for, 37-8, 40-1; condensers' effects, vi, 304-5; conversion to direct, 330-48; cycles, 153, 154-5; inductance, 166-7, 169 (see Inductance); lag and lead phases, vi, 167-9, 171-4, vii, 362; lighting and magnetic effects, vi, 155-7; measurement of power, 165-9, 172; Ohm's Law for, 164-5, 170; sonic waves and, v, 108; transmission of power by, vi, 159-60, 195-6; uses, common and special, 152; use in electric furnaces, vii, 305-6; use in electrotherapy, 236-7, 244, 248-9; use in traction, vi, 161-3, vii, 186, 196; use in wireless, iv, 315, vi, 163; voltage changed, 159-60 (see Transformers); voltmeters for, vii, 154-5, 161-5; wattmeters for, 172, 173, 177 Alternating Current Generators, iv, 307 (see also Alternators) Alternating Current Motors, vi, 240-63 Alternation of Generations, xiii, 160, xvi, 166 Alternators, construction, types, and uses, vi, 157-9, 196-216; operation in power plants, 357, 374; ratings, 192-4; synchronizing action, 383-4; voltages attained, 159; wireless, vii, 290-1 Altimeter, i, 72, 366 Altitude, barometric measurement of, iv, 124; barometric pressure and, i, 23, 72, 171, 303; climatic effects, xiv, 220, 223, 364-6; potential variations with, i, 144-5; pressure table, iv, 124; rock weathering in relation to, xiv, 40; sound and, i, 186-8; temperature and, 19, 20, 303 Alto-Cumulus Clouds, i, 100, 101, 103, 298 Alto-Stratus Clouds, i, 100-3 Alum, Alums, viii, 312-13; in water filtering, 320 Aluminum, Aluminium, affinity strength, viii, 128; atomic weight and symbol, 383; chemical activity, 149, 155; compounds, unstable, 137, 257; density of, iv, 113; electrical conductivity, 283; electrolytic reduction, vii, 320, viii, 271, 284; gold plating of, vii, 319; in heavy metal group, viii, 126-7; melting point and heat, iv, 162, viii, 384; occurrence, 19, 129, 148, 154, 198; percentage in earth's crust, iii, 308, viii, 192; production and uses, iii, 369-70, viii, 154-5; salts astringent, 116; sound velocity in, iv, 201; specific gravity, viii, 384; test for, 287, 288-9 Aluminum Arresters, vii, 17, 50 Aluminum Wire, vi, 80, vii, 23 Amalgam, defined, viii, 373 Amalgamation, defined, vi, 132; in electric cells, 132, 139; in gold and silver extraction, viii, 131, 270 Amaryllis Family, xiii, 188 Amatus Lusitanus, x, 58 Amazon River, arapaima fish of, xii, 154; arrau turtle of, 193-4; Black caiman of, 198; electric eel of, 160; forests and swamps, xiii, 360; jaguars of, xii, 362; length and volume, xiv, 189; poison of natives on, xv, 228; tributaries, connections, xiv, 187; water boas of, xii, 216; water lily of, xiii, 359-60 Amazon Stone, iii, 328 Amber, in varnishes, viii, 265; insect remains found in, iii, 16, 280; magnetism of, iv, 256, vi, 11, 12 Ambergris, xii, 299 Ambrose Channel, dredging of, v, 257-8; sediment in, xiv, 269; wireless pilot system, vii, 284-5 America, antiquity of man in, xiv, 149; compass needle directions in, iv, 246; discovery and settlement of, xiv, 309-11; discovery of, effect on botany, x, 45; first hospital in, 81; plants restricted to, xiii, 320; vegetables and fruits originating in, 222-7 (see North and South America) American Buildings, dryness and heat in, i, 322-3, xiv, 353 American Colonies, Appalachian barrier, xiv, 191, 194, 242, 243, 249; first hospital, x, 81; independence results, 107; medicine in, 81, 104; ordeals practiced in, xv, 373; westward growth by rivers, xiv, 193-4 American Indians (see Indians) American System (Manufactures), v, 48-56, 213-14 Amethyst, iii, 337; oriental, 327 Amides, viii, 373; acid, 230 Amines, viii, 210, 214, 215, 373 Amino, defined, viii, 374 Amino Acids, chemistry of, viii, 230, 309-10; physiological origin and use, ix, 279-84, 287-8, x, 204, 277, 278, 279; proteins compose of, viii, 230, 351, 352 Amino Compounds, viii, 236-7 Amino Derivatives, viii, 210, 214, 215 Ammeters, iv, 279-80, vii, 165-72, 361; automobile, 121; galvanometers as, 179; hot-wire, 163-4 Ammonia, viii, 68-70; amines from, 215; atmospheric, i, 11, 13, ix, 269; boiling and freezing points, iv, 173; critical temperature and pressure, 173; density of, 113; discovery, xvi, 120; Gay-Lussac's studies, 133; in explosives, viii, 74, 75, 253; in fertilizers, 147, 253; in ice-making, v, 357, 358, 380, viii, 69, 70; in nitrogen cycle, 73; in sweat, ix, 276; metal test, viii, 288-9; name, 98; production, natural and artificial, i, 13, 35, 36, 153, viii, 46, 47, 68, 74, 75, 252, 253, 276, 278, xvi, 165; production and disposition in body, ix, 284-5, x, 279-80; refrigeration by, iv, 174, 187-8, viii, 69-70; solubility, 111 Ammonia Water, viii, 68, 147 Ammonites, iii, 275, xii, 75 Ammonium, viii, 93, 147; test for, 287, 289 Ammonium Compounds, viii, 147; carbonate, 137; hydroxide, 70, 121, 147, 288; nitrite, 121; salts, 147, 280; sulphide, 289 Amorphous, defined, viii, 374 Ampère, A. M., vi, 20-1; current unit named for, iv, 278; rule of magnetic deflection, 275 Ampere, electric current unit, iv, 278, 284, vi, 69, 70, vii, 361 (see also Electric Currents, Ohm's Law) Ampere-turns, iv, 288, vii, 362 Amphibians, iii, 285, xii, 167-81; age of, iii, 20; first appearance of, xv, 71; in oceanic islands, xiv, 278; relations to fishes and reptiles, iii, 284, 286, xii, 165, 183 Amphibole, iii, 321-3 Amphitheatres, mountain, iii, 66 Amphoteric, meaning, viii, 352 Amundsen, Capt., aeroplanes of, i, 46 Amyl Acetate, viii, 221 Amyl Alcohol, viii, 210, 214, 249 Amylases, viii, 357, x, 326 Amyloid, viii, 255 Anacondas, (boas), xii, 216 Anadromous Fishes, xii, 155 Anaërobic Bacteria, in peat production, xiii, 313; in sewage treatment, viii, 328 Analytical Chemistry, viii, 285-95 Analyzers, crystal, iv, 354 Anamnesis, x, 370 Anaphylaxis, x, 212-15, 223 Anatomy, Chinese systems of, x, 13; development of science of, 24, 30, 41-2, 44-5, 49, 51-2, 81, 116, 117, xvi, 82-3, 179-80 Anaxagoras, on origin of earth, ii, 366-7; theory of matter, xvi, 83, 118 Anaximander, theory of universe, ii, 367, xvi, 77-8 Anaximenes, theory of universe, ii, 366-7, xvi, 79 Andes Lightning, i, 149 Andes Mountains, glaciers of, xiv, 54; impassability, 250; lightning, i, 149; mineral wealth, xiv, 237; rivers, 167; snow pinnacles, i, 116-17; upraised in Cretaceous Period, iii, 219; volcanoes, xiv, 315; youthfulness of, 96, 235 Andrews, Thomas, i, 29, xvi, 175 Andromeda, nebula in, ii, 135-6, 136-7, 357, 361; new stars in nebula, 332-3 Anel, Dominique, x, 90-1 Anemia, x, 337; blood transfusion in, 338; cause and effects, xi, 370-1; of adolescence, x, 237; pernicious, discovery of, 112 Anemograms, i, 295, 366 Anemometers, i, 83-4, 366; for gusts, 295 Aneroid Barometer, i, 71, 72, 366, iv, 123-4, 381 Anesthetics, discovery and use in surgery, x, 123-5, 148, xvi, 180, 185; effect on impulses, xi, 20; Hindu use of, x, 13; medieval, 41 Aneurisms, x, 28 note; formation and rupture of, 336; treatment of, 28, 91-2 Angel Fish, xii, 164 Anger, xi, 139, 141; basic causes of, ix, 153, 166; expression of, by monkeys, xv, 64; in various sentiments, xi, 146, 148, 149, 150; pain and, 120; physical accompaniments of, ix, 240-1; self-forgetfulness in, xi, 134 Angiosperms, xiii, 175-9; alternation of generations in, xvi, 166; first appearance and spread, iii, 256-7, xiii, 317-18 Anglers, (fish) eyes of, xii, 138; "lure" of, 133 Angleworms, xii, 51-3; power of distinguishing light, ix, 105 Anglo-Saxon Language, xv, 156-7 Anglo-Saxons, in Nordic group, xvi, 48; use of tea, xiii, 229 Angular Diameters of Stars, ii, 150-1; measurement of, 322-3 Anhydride, defined, viii, 374 Aniline, viii, 52, 237 Aniline Dyes, xvi, 163; fluorescence of, iv, 379 Animalculæ, (see Unicellular Animals) Animal Electricity, vi, 16, 17, 19, 23, 64 (see also Electric Fishes) Animal Fats, viii, 246 (see Fats) Animal Kingdom, classification, iii, 259-60, xii, 25-9; how distinguished, viii, 349, xii, 14, 15, xiii, 13, 14; relations to vegetable, viii, 334 Animal Protein, ix, 279, 280 (see also Proteins) Animals, xii, 270; activities of, ix, 20-1; adaptation to environment, v, 16-18, 24, xvi, 152; admiration unfelt by, xi, 146; æsthetic emotions, xvi, 145-6; anaphylaxis in, x, 212, 213, 214; appendix uses in, xv, 56; appetite in, ix, 88; arctic, in mountains, xiv, 376-7; artificial heat use by, ix, 308, xv, 229-30; body heat regulation in, ix, 307, 308, 311; brain in, xv, 62-3; cannibalism in, ix, 280-1; care of skin and coverings by, x, 310; care of young, xv, 275-6; carnivorous, xii, 332-65; cell structure, 25; chemistry of body and nutrition, viii, 348-70; chromosomes in different species, ix, 46; classification, xii, 25-9; climatic influences, xvi, 141; climatic limitations, xiv, 363-64; cold-blooded (see Cold-blooded Animals); communication means, xv, 140-1; courtship of, 274-5; differences of protoplasm in, ix, 278-9; direction perception by, 117; differences of complexity in, 48-50; diseases of, x, 206; distribution facilitated by land arrangement, xiv, 21; domestication of, xv, 197-8; ear movements in, ix, 82, 117; educability of, xv, 66; embryological development, 54-5; evolution, Anaximander on, xvi, 78-9; experience, profiting by, ix, 139, 152, xv, 66; expressions of emotions by, 63-5; face and brain case in, 43; fear in various, xi, 136; fear and anger effects, ix, 166; flesh of, as food, 24, 284-6, xv, 333-4; foods of, viii, 349, 350, ix, 24, 29, 30; food procuring by, 18-20, 73-4; geological history, iii, 12, 259, 306; grasping ability of, ix, 67, 68, 82; growth of, on what dependent, 287-9; hair erection in, 161, 166; heredity in, x, 231-2; hoofed, xii, 300-31; hunger and thirst senses in, ix, 87; hunting and trapping of, xv, 222-7, 227-8; hypertrophy of heart in, x, 331-2; imagination in, xi, 224; imitation in, xv, 66; impulses instinctive, 273; instincts of, 65-6; land (see Land Animals); later than plants, xiii, 298; Latin names, xii, 28-9; leadership among, xv, 361; light and darkness effects on, x, 253; locomotion, v, 215, ix, 73-4; luminous, i, 346-7; man's lessons from, xv, 206, 208, 220; man's relation to, 53, 68; marine (see Marine Animals); "moral standards" applied to, xii, 351; mutation in, ix, 342; nitrogen uses, viii, 73; of continental islands, xiv, 271; of oceanic islands, 277-8; oldest known remains, iii, 238, (Pl. 13); physiology of, remarks on, ix, 305; plants and interrelations, viii, 334, 335, 347, 349, 350, xiii, 82; power development in, ix, 15, 16, 17, 18; protective devices, xv, 16-18; qualities, studies of, xvi, 143; rate of increase, xv, 19-21; reason in, xi, 243-4, xv, 67-8; reflex actions in, 65; regulatory mechanism in, x, 249-50; reproduction from cells, 228, xvi, 155-6; salts in body fluids, ix, 175-6; seasonal phenomena, i, 254, 256; seed dispersal by, xiii, 55, 58, 340, 343; sense of sight in, ix, 105; sense of smell in, 96-7, xi, 82; sex relations among, xv, 274, 276-7; smelling motions in, ix, 82-3; struggle for existence among, xv, 21-2; tool-using by, v, 9-11, x, 67-8; touch sense in, 91; unicellular, (see Unicellular Animals); useful, xii, 324-31; variation in, xv, 22-3 (see Variation); vitamine needs and stores, x, 256-60; warm and cold blooded, ix, 305; water scarcity effects, 37-8; wild, xii, 332-65; young, metabolism in, ix, 38-9 Animal Starch, viii, 350 Animal Worship, xv, 333-4, 340-1 Animists, Animist Theory, x, 84-5 Anion, defined, iv, 381 Annuals (plants), xiv, 367; garden species, xiii, 289, 297; life of, 53, 152; roots of, 15, 16 Anoa, of Celebes, xii, 330 Anode, defined, iv, 317, 381, vii, 251, 362; first defined by Faraday, vi, 23 Antarctica, blizzards of, i, 133; coal deposits, 199; extent and elevation, xiv, 20, 22, 26; former connection with S. America, 290; glaciers of, 55; island or continent, 23; plateau, 222; penguins of, xii, 251; rainlessness, i, 109; uninhabitability, xiv, 21; winds of, i, 128-9 Antarctic Ice Sheet, iii, 62, 237 Antarctic Ocean, current of, xiv, 299, 305; extent of, 22-3; sea elephant of, xii, 335; whales of, 298 Antares, angular diameter, ii, 151, 322-3; color, 297; former name, 302; gaseous state, 382; type III star, 115 Anteaters, xii, 281-3; banded, 274; scales of, xv, 220-1; spiny, xii, 272-3 Antecedent Rivers, xiv, 164-70, 174 Antelopes, xii, 326-8; fear in, xi, 136; hunting of, with cheetah, xii, 365; pronghorn, 322-3 Antennæ, of insects, xii, 100-1 Antennæ (wireless), iv, 314, vii, 261; construction, 264-5; effective resistance, 298; fundamental wave-lengths, 266, 294; of receiving stations, 267; types, 295-6 Antenna Circuit, vii, 263-7; energy dissipation, 297-8; inductance and capacitance, 294-5, 296-7; radiation, on what dependent, 298 Anthelion, i, 366; oblique arcs of, 378 Antheridia, xiii, 158, 159, 161 Anthers, of flowers, xiii, 45, 118, 119 Anthracene, viii, 240, 253 Anthracite Coal, iii, 344; beds in U. S., 347-8; constituents, 345, viii, 44; graphitic, iii, 345; lessening supply, 346; loss of heat with, v, 155 (see also Hard Coal) Anthrax, Koch's studies of, x, 149; Pasteur's work on, 140-2 Anthropoid Apes, xii, 381-4; primates, 373; susceptibility to human diseases, x, 206 ANTHROPOLOGY, Volume xv, defined, xv, 10, 11, 15, xvi, 36, 47; daily interest, 26, 29 Antibodies, x, 205, 216 Anticathode, defined, iv, 381 Antichlor, viii, 140 Anticline, defined, iii, 377; illustrated, 85, 128 (Plate 7), xiv, 95 Anticrepuscular Rays, i, 169, 366 Anticyclones, i, 134-5, 366, xiv, 349, 350; Siberian, i, 218 Antigens, x, 205, 217 Antimony, affinity strength, viii, 128; atomic weight and symbol, 383; expansion on solidifying, iv, 150; fusibility, viii, 384; ores, 198, 270; specific gravity, 384; tests, 287-8; uses in industry, 169; use of, in medicine, x, 12, 50, 169 Antinodal Current, vii, 297 Antinori, Luigi, i, 213 Antiseptics, viii, 332-3; Carrel-Dakin solutions, x, 181-3, 382; discovery, 40, 145-6, xvi, 180, 182-3 Antiseptic Surgery, x, 146-7; history of development of, 40, 55, 145-6, 381-2, xvi, 108, 114, 182-4; in World War, x, 181-3, 381-2 Antitoxins, x, 218, 296-8; of diphtheria, 197, 212, 213-14, 218, 296-8; of tetanus, 218, 299 Antitrade Winds, i, 366, xiv, 348 Anti-twilight Arch, i, 167, 366 Antlers, xii, 316, 317, 319 Ant Lions, xii, 106 Antony, Mark, speech on Cæsar, xi, 331 Ants, aphids of, xii, 101; appearance in Triassic, 104; nest repairing by larvæ, v, 10; numbers in tropics, xii, 282; "showers" of, i, 357; social habits, xii, 124, 125, 126; underground rooms of, xv, 266 Antwerp bombardment, audibility, i, 191; harbor of, xiv, 270 Antyllus, x, 28 Anuria, x, 344-5 Aorta, ix, 196, 201 (fig.), x, 334; elasticity of, ix, 210; ligation of, x, 129-30 Aoudad, xii, 326 Apatite, iii, 323, viii, 193 Apes, anthropoid, xii, 381-4; black of Celebes, 379; brain of, xv, 62, 90-1; embryological development, 54-5; imitation in, 66; manlike, iii, 301-3, xv, 88-95; man's relation to, xv, 56-7; nostrils of, xii, 376, xv, 46; physical comparison of, with man, iii, 301, (fig.), xv, 57-62; reasoning power, 67-8; sex relations among, 277-8; skull capacity, xv, 89; skull shape, 42-3; tigers and, xii, 362; tool-using by, v, 9; working methods, xv, 58 Aphids, xii, 118; ants and, 101 Aphis Lions, xii, 106 Aphrodite (sea mouse), xii, 54 Apian, Peter, ii, 41; comet of, 85 Aplysia, xii, 68 Apollonius of Perga, ii, 31, xvi, 90 Appalachia, iii, 195, 205, 210 Appalachian Mountains, antiquity of, xiv, 96, 235; Catskill formation, iii, 195; coal beds, iii, 346-7, 204, xiv, 237; folding intensity, iii, 86, xiv, 36, 230; forests, xiv, 372; former elk of, xii, 317; geological history, iii, 130, 132-4, 135-6, 140, 191, 205-7, 210, 219, xiv, 97-8, 168-9, 228-9, 235-6; "grain" of, xiv, 99; historical rôle, 191, 194, 242-3, 249; igneous formations absent, 228, 230, 234; iron deposits, iii, 358-9; length and breadth, xiv, 36-7, 227; limestone soils, iii, 27; marble production, 371; metallic ores of, xiv, 237; non-marine deposits in trough, iii, 209-10, 214; petroleum fields, 350; plateau west of, xiv, 221; present relief, origin, iii, 231-2; ridges and valleys, 36, 137, 233-4, xiv, 94, 97-8, 234, 236; rivers across, iii, 36, 137, 233, xiv, 166-7, 168-9, 180-2; site formerly submerged, iii, 12, 130, 168, 181, 184, 187, 194-5, 197, 198; springs, thermal and mineral, 128, xiv, 143; strata, thickness and composition, iii, 132, 180, xiv, 228-9; strata of various periods, iii, 184, 187, 195-6, 203; stream capture in, xiv, 180-2; thrust faults, iii, 90; typical range, xiv, 226; wind and water gaps, iii, 39, xiv, 58, 98, 169 Appalachian Revolution, iii, 205, 208, 210 Appalachian System, xiv, 227 Appalachian Valley, xiv, 167 Appendicitis, asepsis in, x, 147; cause of, 224 Appendix, ix, 233 (fig.); as infection center, x, 220; in man and animals, xv, 56 Appetite, ix, 87-8, 299; exercise effects, x, 303-4 Apples, acids of, viii, 223; development of, xiii, 54; food value, viii, 365, ix, 250-1, 299, x, 268 Apple Tree, family, xiii, 197-8; origin, 224; petal arrangement, 190 Apteryx, xii, 249 Aquamarine, iii, 325 Aqua Regia, viii, 174 Aquatic Animals, mental inertness of, xii, 140, (see also Crustaceans, Mollusks, Naids, Polyps) Aquatic Plants, first on earth, xiii, 300, 301, 303; fertilization, 123, 149-52; fossils, 303; in lakes, xiv, 210 Arabia, animals of, xii, 249, 327, 342, 344, 359; Danish scientific expedition, xvi, 123; plains of, xiv, 217; source of coffee, xiii, 231, 283 Arabian Horses, xii, 307 Arabian Language, xv, 162; words from, in English, 161 Arabic Numerals, xv, 184, xvi, 62, 103 Arabs astronomy of, ii, 11, 36-9, 302, xvi, 100; bananas known to, xiii, 216; mathematical advances, ii, 12, xvi, 54, 103; medical science of, x, 31-3, 36, 37-8, 39, 40, 100; sciences of, xvi, 54, 100; sugar introduced by, xiii, 215 Arago, discovery of magnetism of rotation, vi, 21; lightning studies, i, 146 Aral, Sea of, depression of, xiv, 203; shallowness and salinity, 206-7; size of, 204 Arapaima Fish, xii, 154 Arara Cockatoo, v, 9-10 Arcadian Range, xiv, 227 Arcathagus, x, 25 Arc Furnaces, vii, 303 Arc Generators, vii, 291 Archæopteryx, xii, 239-41 Archegonia, xiii, 158, 159, 161 Archeozoic Era, iii, 164-75; life in, 262, 263, 265, xv, 71 Archeozoic Rocks, iii, 164-74; graphite found in, 249-50; iron ores in, 358 Arches, false and true, xv, 268-9; weak in earthquakes, xiv, 342 Archimedes, iv, 25, 26; mathematical and other work, xvi, 89, 90; principle of, iv, 30, 102-5, 107; screw of, 26-7 (fig.) Arc Lamp, Arc Light, iv, 310-11, 352, vi, 279, 280-3; Bunsen's carbon rods, xvi, 189; compared with sun, ii, 169; Davy's experiment with, vi, 19; direct and alternating currents on, vi, 332, vii, 208-9; graphite electrodes, vii, 300, 308 Arc Process, i, 36, vii, 323-4 Arcs of Lowitz, i, 366 Arctic Archipelago, xiv, 20 Arctic Current, xiv, 304-5 Arctic Ocean, copepods of, xii, 84; depths, xiv, 22; enclosed character, 22, 290, 299 Arctic Plants, in mountains, xiii, 321, xiv, 365-6, 376-7 Arctic Regions, conditions of life in, xv, 123-4; forests of Coal Age, xiii, 307; frozen soil of, xiv, 75; growing season in, 375; plant conditions in, 365; seals of, xii, 335; skin canoes of, xv, 264; snow line in, 72-3; wolves of, xii, 340-1; winds, i, 127, 128 (see also Polar Regions) Arcturus, angular diameter, ii, 151; decreasing distance, 120; displacement lines in spectrum, 119; gaseous state, 382; origin of name, 302; parallax, 316; "solar" star, 115 Arequipa Observatory, ii, 145-6 Arethusa (plant), xiii, 186 (fig.) Argentina, ancient sloths of, xii, 283; hail rods, i, 343; pampas of, (see Pampas); stock-raising, xiv, 384; weather service, i, 228-9 (note), ii, 186-7; wheat cultivation, xiii, 211 Argon, discovery and character, i, 10, 11, 12, viii, 67, 181, 309; electric lamp filler, i, 33; periodic classification, viii, 182-3; symbol and atomic weight, 383 Argonauts, (shellfish), xii, 77-8 Argonne Forest, xiv, 91 Arid Regions, alkali deposits, viii, 139; dust whirls, i, 60; mineral matter in waters, viii, 196; plants of, xv, 18-9; rainfall of, i, 109, 112; rock weathering in, xiv, 41-2, 51-2, 77-9, 124; soils of, 68-9, 383 (see also Deserts) Aristarchus of Samos, ii, 10, 27-8 Aristillus, ii, 28-9, 31 Aristocracy, changing ideas of, xv, 377 Aristocratic Type, xiii, 356 Aristotle, association principles, xi, 197-8; authority in Middle Ages, ii, 33, 42; conception of cosmos, ii, 367; lectures on fossils, etc., xvi, 168; medical work of, x, 23, 27, 74; meteorological treatise, i, 67; monad theory, xvi, 118; on falling bodies, ii, 53; on knowledge and perceptions, xvi, 87; on Mars, ii, 227; on origin of earth, xvi, 78; on shooting stars, ii, 283; scientific methods, xvi, 88-9; syllogism invention, 88; zoölogical work, 126 Arizona, arid topography, xiv, 42; cactus plants, xiii, 28, 106-7; chapparal of, xiv, 379; cliff lines of, 88; climate of plateau, 222; copper mines, iii, 360; faults at Bisbee, 90; forests of, xiv, 220-1, 373-4; Gila monster of, xii, 204, 207; mesas, xiv, 82; sunniest state, i, 86; timber limits, xiv, 373; volcanic fields of, 102, 315, 317, 318 Arkansas, aluminum production, iii, 369; hot springs of, xiv, 143, 144; malaria campaign in, x, 173-4 Arkwright, Richard, v, 274, 376 Armadillos, xii, 282, 283-4; scales of, xv, 220 Armature Reaction, vi, 190, vii, 145-6 Armatures of Dynamos, iv, 307, vi, 176, vii, 362; of direct current generators, vi, 178, 179-86; of alternators, 196, 197-8, 202, 205, 207, 210, 212-13 Armatures of Magnets, iv, 250, vi, 30 (fig.), vii, 362; uses of, iv, 291-2 Armatures of Motors, vi, 223, 224-5, 235-6 Armies, crowd psychology in, xi, 326-7; fatigue in retreat, 275 Armor, development of, xv, 220-1 Armored Cable Wiring, vii, 61-2, 362 Armor Fishes, iii, 281, 282, 284 Armorican Range, xiv, 96, 235 Armor Plate, making of, v, 323, 382 Arms, arteries of, ix, 196-7; bones of, 67-8, (fig.), 77, (fig.); bones, growth of, 58; equal length of, 169-70; freedom of movement of, 66; grasping organs, 82; length as yard measure, iv, 45; length in man and apes, xv, 57, 59; muscles of, ix, 76-7 Arnold of Villanova, x, 41 Aromatic Hydrocarbons, viii, 232-6, 374 Arrack, from coco palm, xv, 125; Indian, xiii, 213 Arrhenius, on Martian life, ii, 248 on osmotic pressure, xvi, 164; theory of life, xii, 9 Arrows, development, and use of, xv, 213-16; Indian, 196 (fig.) Arsenic, affinity strength, viii, 128; atomic weight and symbol, 383; in copper ore, vii, 320; ores of, viii, 198, 270; properties, 169; specific gravity, 384; tests for, 201, 287, 288 Art, primitive types of, xv, 110-21; science and, iv, 9 Arterial Blood, ix, 260, 263, 264 Arterial Pressure, ix, 213-14, x, 334 Arteries, ix, 191, 196-7, x, 334; bleeding from, discovery of, 39; caliber changes in small, ix, 215; connection with veins, 192-3 (fig.), 197; elasticity of, 59, 210-12, 213-14; former ideas of, x, 62, 63, 65, xvi, 106; hardening of, x, 334-6; ligating of, 56, 96; "man as old as," ix, 214, x, 335; passage of blood along, ix, 211-12; systole and diastole of, x, 62, 63-4, 65 Artesian Wells, iii, 118-19, xiv, 138; constancy of, 152; of North Dakota, 12, 139; warm water from, 144 Arthropods, iii, 260, 263, 264, 276-80, xii, 81, 126 Arthur's Seat, Scotland, xiv, 112 Artichokes, xiii, 206, 222 Artificial Ice, production, v, 349-50, 354-8, viii, 69, 70 Artificial Light, colors in, ix, 115; gains from, iv, 51 Artificial Limbs, x, 190 Artillery, armor versus, v, 368; distance audible, i, 188-9 (see also Guns, Projectiles) Artillery Plant, xiii, 56 Arts, æsthetic, origin and development, xv, 296-325 Arts of Life, xv, 205-72 Arum, fertilization of wild, xiii, 153 Arum Family, xiii, 188; flower arrangement, 52 Aryan Languages, xv, 161, 162, 163 Aryans, in Nordic group, xvi, 48; of India, 53; rule of fathers among, xv, 367 Asbestos, iii, 338 Ascension Island, xiv, 289 Ascidians, xii, 19, 20, 129 Asclepiades, x, 25-6 Asepsis, in surgery, x, 14, 134, 146-8; Lister on, 144-5 Ash, viii, 374; handling in power plants, vi, 356; of coal, viii, 44, 45; of plants, xiv, 65-6; volcanic, 324 Ash Trees, for gardens, xiii, 271-2; leaves, 36-7; seed dispersal, 58, 343 Asia, animals of, xii, (herbivora), 302, 305, 313, 314, 317, 320, 327; animals (carnivorous), 336, 339, 344, 345, 352, 356, 357, 365; birds of, 263; climate changes, results, iii, 75, xiv, 361-2, xvi, 141; climate of eastern, xiv, 345; crocodiles of, xii, 201; drainage system, xiv, 190, 195-6; earthquake belts, 331-2; eastern coast, 248-64; faulted topography of eastern, 124-5; food plant regions, xiii, 221; forests, xiv, 369-77; formerly united with America, xii, 313, xiii, 351, xiv, 30; geological history, iii, 216, 235-6; grasslands and deserts, xiv, 381; monsoon countries, conditions in, 359-60; plains, 217; plants common with America, xiii, 351; plateaus and mountains, xiv, 217-22; rodents of, xii, 287-9; rubber production, xiii, 248; salt lakes, viii, 139; snails of, xii, 69; snakes of, 218, 226, 229, 231, 232; terrestrial leeches, 55-6; trees of eastern, xiv, 377; vegetables and fruits originating in, xiii, 222-7; volcanic fields, xiv, 316-18; wind types, i, 131, 134, 136 Asia, Central (see Central Asia) Asia Minor, climate changes in, xiv, 361-2; plateau of, 222 Asiatic Volcanic Belt, xiv, 316 Asparagus, effects on urine, ix, 274-5; green food, 27; origin, xiii, 222; stem of, 30 Asps, xii, 230 Assam Earthquake, iii, 98, xiv, 334 Asses, xii, 308 Association of Ideas, ix, 150-1, xi, 197-207; in language, ix, 151-2; memory and, 149-50; in imagination, xi, 219-20, 209, 212, 216-17; necessary to attention, 232-3, 234; normal and abnormal complexes, x, 355 Assyria, civilization conditions, xv, 127; art of, 301; cuneiform writing, 175 (fig.); history and civilization, xvi, 51-3; skin rafts of, xv, 264; sun-worship and astrology, ii, 20-1 Assyrian Language, xv, 162 Asteroids, discovery, ii, 254-7; in solar system, 163-4; life on, 248; origin, 258, 371, 373, 374; photographic study, 131-2; size, shapes, and orbits, 162, 257-8 Asthma, bronchial, ix, 162, x, 223; from adenoids, 342 Astigmatism, ix, 113-14, xi, 85 Astonishment, and fear, xi, 131 Astraphobia, i, 330-66 Astrolabes, ii, 11, 29, 34, 46-7, 93 Astrology, astronomy and, ii, 9, 20; history in various countries, ii, 20-1, 23, 37, xvi, 58; medical progress and, x, 14 Astronomical Instruments, Bessel on, ii, 93; development of, 10, 11, 12-13, 13-14, 16, 161 Astronomical Photography, ii, 125-38; in corona studies, 221-2, 225; in parallax work, 314; in nebular studies, 358; telescopes used in, iv, 372-3 Astronomy, daily interest of, xvi, 12; defined, 37; exact science, x, 368; history of, ii, 9-92, iv, 19, xvi, 56-8, 61, 69, 70, 81-2, 90-1, 100, 101, 102, 103, 124-5; mathematical and descriptive, ii, 15, 16; meteorology and, i, 7; new and old, ii, 113-14; personal measurements in, xi, 155-6; spherical, ii, 29 Astronomy Today, Volume ii Athletes, "form" in, ix, 159 Athletic Contests, value to spectators, xi, 139-40 Atlantic Cables, laying of first, vi, 24; Telegraph Plateau and, xiv, 288 Atlantic Coast, shoal-water belt, xiv, 25, 285 Atlantic Coastal Plain, xiv, 213-14; artesian wells in, iii, 119; forests, xiii, 371, xiv, 372-3; geological history, iii, 212-13, 216, 221, 231; soils and agriculture of, xiv, 218-19 Atlantic Drainage System, xiv, 189-90 Atlantic Ocean, airship flights across, iv, 107, v, 228-30, 233; birds of, xii, 251, 252, 253; climates on opposite coasts, xiv, 345, 346-7; clipper's time across, v, 188; conformation of floor, xiv, 288-90; coral reefs in, 264; depths, iii, 51; extent of, xiv, 22; first steamship, v, 192-3, 378; herring fisheries, xii, 156; oceanic islands of, xiv, 277; salt in, viii, 139; temperature of water, xiv, 14, 297; trade winds, i, 127, 130; tree corals of, xii, 43; unchanged for ages, iii, 55; weather charts, i, 276; wireless weather reports, 280 (see also North Atlantic) Atlantic Seaboard, rainfall, i, 112; super-electric zone, vi, 384 Atlantic Type of Coasts, xiv, 247, 249-50 Atlantic Volcanic Belt, xiv, 316 Atmometers, i, 88-9, 366 Atmosphere, anatomy of, i, 9-23; circulation (winds and storms), 123-40, xiv, 347-51; composition (gases), 9-16, viii, 66-8, 152; dense, effects of, iv, 31-2; density decrease upward, i, 16, 17, 171, 173, 303, iv, 108, 124, ix, 267-8, xiv, 354; density irregularities, optical effects, i, 171-2; disease germs in, 325-6; dust and smoke in, 52-65, 325, vii, 216-17, ix, 269; effect on colors of stars, ii, 296; effect on meteors, 283, 285, 290; effect on sunlight and colors, i, 165-6, 167-71; electrification, 144, 145, 146, 150, vii, 207, 212-13, 216-17; heat absorption by, iv, 194; heating of, by sun, i, 123; heat retention by, ii, 244, 382, iv, 183-4; height, i, 16-18, ii, 244, iv, 116; highway, i, 39-51; layers (see Stratosphere, Troposphere); light of, 164; magnifying of, by telescopes, ii, 98, 140, 141; meteorology, science of, i, 7; nitrogen fixation from (see Nitrogen Fixation); oxygen in upper, ix, 267-8; radioactive emanations in, i, 143; resources in, 24-38; theories of origin, iii, 160, 163; topographical work of, xiv, 62-79; weight, i, 23, ii, 279, v, 222-30 (see also Air) Atmosphere (unit of pressure), iv, 121, 123, 381, viii, 107 Atmospheric Acoustics, i, 186-96 Atmospheric Electricity, i, 141-63, vii, 201-19, 362; in climatology, i, 211; physiological effects, 330 Atmospheric Engine, Newcomen's, v, 144 Atmospheric Optics, i, 164-85, iv, 327-9 Atmospheric Pressure, amount and direction, i, 23, ii, 244, iv, 116-23, v, 222, viii, 107; amount at different elevations, iv, 124; body regulation to, x, 250; boiling point and, iv, 170, viii, 303; discovery of, iv, 114-16, 132, v, 112; early experiments with, iv, 29-30; equalization in ear, ix, 102; isobars, i, 125-26; life in relation to, ii, 245-48, xi, 53; measurement, i, 70-2, iv, 120, 121, 123, 124; physiological effect of changes, i, 303, 327-9; stratosphere in relation to, 20; unit of, iv, 121, 123, 381, viii, 107; variations with temperature, iv, 121-3, 124-5; weather and, i, 70, 237-8, 241-2 (see also Pressure Areas); winds in relation to, 124, 125-6, 127-9, 134-5; work done by, 25, v, 112-15, 137-8 Atmospheric Refraction, i, 167-74, 380, iv, 327-30; early studies of, ii, 32, 41 Atolls, xii, 41 Atomic Energy, ii, 384, v, 181, viii, 186-7 Atomic Numbers, viii, 183, 309 Atomic Theory, history and deductions, viii, 110; in Greek philosophy, xvi, 83-4, 87, 118; Leibnitz's, 117-18 Atomic Volume, determination, viii, 307 Atomic Weights, viii, 92, 383; chemical calculations by, 96; classification of elements by, viii, 177-83, 189, xvi, 163; determination of, viii, 306-7; hydrogen basis, 33; introduction, xvi, 134; physical state and, viii, 297-8; properties dependent on, xvi, 134; radioactivity and, viii, 184, 185-6, 188; regular increase in similar elements, 132, 176, 179; specific gravity and, 313; specific heat and, 308-9; table, vii, 384, viii, 383 Atomists, school of, xvi, 84-6 Atoms, viii, 25-7; asymmetric, 309-10; chromophor groups, 258; defined, iv, 21, vi, 110-11, viii, 374; vii, 362, disintegration, 185-7, 188; dissociated, in ball lightning, vii, 214-15; electrification, vi, 122-3; energy of (see Atomic Energy); Greek theory, xvi, 118; laws involving, viii, 110; Leibnitz on, xvi, 118; magnetic fields of, vi, 117; motion within, viii, 309-10; of body, Epicurean theory, x, 26; size, vi, 112-13, 115; stability, vii, 215; structure of, iv, 23, 55, vi, 113-15, 120-1, viii, 187-9, 307; unchangeableness, 175-6 Attention, xi, 228-36; habit and, 253-5; methods of arousing, in advertising, 344-8; ordinary meaning, 40 Attraction, scientific meaning, vii, 362, iv, 96 Audibility, distances and variations, i, 187-92; vibration limits of, iv, 204, ix, 99 Audion, iv, 315-16, vi, 339 (fig.), vii, 279, xvi, 191-2 (see also Vacuum Tube) Auditoriums, acoustic qualities, iv, 239; cooling system, 188; echoes in, 238 Auditory Nerve, ix, 101 (fig.), 142, xi, 30, 102; internal and external stimulations, iv, 203 Auenbrugger, Leopold, x, 98-9, 110 Augite, iii, 336 Augustinus, Aurelius, xvi, 99-100 Auks, xii, 264-5 Aurelians, xii, 116 Aureoles, i, 184, 370 Aurignac Cave, iii, 305 Aurignacian Implements, xv, 100, 105, 108-9 Aurochs, xii, 331 Aurora, i, 158-62, 367; altitude, 17; magnetic disturbances with, vi, 40; ozone from discharges, i, 16; sun-spots and, ii, 176, 186 Ausable Chasm, iii, 44, 243, xiv, 128, 131 Auscultation, x, 108-10, 371 Australia, animals of, xii, 204, 249, 272, 274-5, 276-7, 278-80, 285; barramundi fish of, 154; barrier reef of, xii, 41, xiv, 263; big trees, xiii, 26; black swan of, xii, 259; "bush" of, xiv, 378-9, 380; bushmen, iii, 304; climate, xiv, 358; coasts, coral reefs on, xii, 40, 41; desert sounds, i, 196; former connections, xii, 277; glacial and coal deposits, iii, 203-4; grasslands, xiii, 373; island or continent, xiv, 23; ladybirds and scales, xv, 22; landlocked area, xiv, 190, 222; mining production, iii, 362, 365, 368, 370; monsoons, i, 131; mountains in Permian Period, iii, 205; parrots of, xii, 266; pearl fisheries of, 62; plateau and plains, xiv, 218-22; rabbit pest in, xv, 20; ria coasts of, 257; rivers and drainage of, xiv, 197; sheep raising, 384; snakes of, xii, 214-29; temperate forests, xiii, 372; timber supplies of, xiv, 382; weather effects on history, i, 324; wheat cultivation, xiii, 211; wild rice, 214 Australians, xv, 193-5; avenging of death by, 368; beards, 38; bird-catching by, 224; boats of, 262; body scarring by, 257-8; boomerang of, 194, 208; chieftains, 364; color, 37; cooking methods, 195, 233; dances and music, 313-14; digging sticks of, 235; dogs used in hunting, 223; dramatic ceremonies and plays, 306, 308-9; duck hunting by, 222; ideas of white men, 334; message sticks, 166-7; parrying stick of, 221; sand drawings, 296; songs of, 319-21; spear-throwers of, 212 (fig.); use of toes by, 61 Austria, beet sugar production, xiii, 216; forests of, xiv, 238, 382; Italy and, xiv, 244-5, 253; Lake Dwellers of, xiii, 210; loess deposits, xiv, 72; Serbia and, 306 Autogenous Vaccines, x, 218 Auto-intoxication, ix, 249-52, x, 255, xi, 370; in mothers, ix, 343-4 Automatic Heat Regulators, vii, 87-8 Automatic Regulation, vi, 101-2, vii, 362-3; of motors, vi, 218, 224-9, 232 Automatic Telegraphy, vii, 112-13 Automatic Telephones, vi, 87, vii, 92-3, 106-7 Automobile Industry, v, 213-14, 383; machine-tools and, 55-6, 214, 383 Automobiles, American, v, 213-14; benzene fuels, viii, 235-6; carburetors, vii, 124-8; clutches, 143; clutches, magnetic, vi, 104; crank shafts, vii, 130-1; cylinders, 130-1; cylinder test, 128; electric systems, 120-50; engines, v, 156-61; engine operation, vii, 123-33; frost around exhaust, v, 128; freezing of radiators, prevention, viii, 299; future fuels, 209; generator output regulation, vii, 144-50; high and low speed air mixtures, 126-7; history of development, v, 207, 212-13, 377, 383; horns, iv, 240-1; ignition system, vii, 130-41, 243; ignition test, 128; ignorance of drivers, 122-3; lighting systems, 122, 135, 141-2; limitations on use, i, 41-2; lubrication, vii, 300; magnesium parts, viii, 127-49; magnetos, vii, 135, 139-41; motion pictures of, iv, 349; mufflers, v, 165; Owen's magnetic, vi, 104; power source, ix, 15, 74; present attitude toward, vii, 299; racing cars, v, 214; roads and, 214-15; springs air-cushioned, 134; starters, vi, 99, 238-9, vii, 120, 127, 135, 142-3; steel alloys used in, xiv, 238; steering-gear, v, 38; storage battery care, vii, 121, 127, 144; tires, v, 133-4, 204; tires burst by heat, iv, 151; unit systems, vii, 135-6; voltmeters, 163 Autonomic Nervous System, xi, 134-5, 137 Autophytes, xiii, 96-7 Autosuggestion, xi, 305-10; in hypnotism, 311-20; in salesmanship, 336-41; in sleep, 287-8; positive, 278 Autotransformers, vi, 327-8, 337 (fig.); in wireless systems, vii, 266-91 Autumn, frosts, i, 258; leaves in, xiii, 79, 175; rate of advance (U. S.), i, 256 Aviators, altitude effects, i, 303; complete rainbow seen by, 175; fog effects, 300-1; heights attained by, ix, 267-8; sense of balance, v, 343; sixth sense, i, 292; training of, x, 242; visibility obstacles, i, 303; weather service for, 206, 227, 230, 231, 233, 286, 304-5 Avicenna, x, 32-3; arterial bleeding unknown to, 39; books burned by Paracelsus, 47; translation of, 38; views of fossils, iii, 14 Avitaminoses, x, 264 Avocations, importance of, xi, 375-6 Avogadro's Hypothesis, viii, 108-9, xvi, 133 Awe, sentiment of, xi, 147 Axolotl, xii, 173 Axons, of nerves, ix, 123-4, 125, 126, xi, 19 Aye-Ayes, xii, 374 Azaleas, xiii, 202, 203 (fig.), 289 Azores, xiv, 276, 289; ocean depths near, 289; rediscovery of, 309; volcanic activity in, 316 Azores Plateau, xiv, 288 Aztecs, civilization, in temperate climate, xv, 123; kings' oath, 366; picture writing of, 169-78 (fig.); tobacco use among, xiii, 257 Azurite, iii, 323 Baal, Phœnician sun-god, ii, 20 Babakotos, xii, 375 Baboons, xii, 379-81; primates, 373 Babylon, wind-blown sand over, iii, 75; world metropolis, xvi, 61 Babylonian Language, xv, 162 Babylonians, astronomy of, ii, 19-21, xvi, 56, 57-8, 61-2; cuneiform writing, xv, 174, 175 (fig.), xvi, 60; debt of Greeks and Egyptians to, 63, 66, 69, 70, 71; Hammurabic code, 63; history and civilization, 51-3, 55, 62-3; idea of cosmos, 77; magic of, 59; mathematics, 61, 62, 103; medicine of, x, 14, 15; science, remarks on, xiv, 96 Babyroussa, xii, 310 Bacilli, x, 195; of various diseases, 149, 165-6, 292, 295, 296, 298-9 Backstays of Sun, i, 169, 367 Bacon, calories in, ix, 299 Bacon, Francis, evolution known to, x, 136; Harvey's small esteem for, 66; influence on his times, 67; on brontides, i, 196; on knowledge, xi, 10; scientific work, xvi, 113, 115, 125, 131 Bacon, Roger, xvi, 100-1 Bacteria, anærobic, xiii, 312-13; atmospheric electricity and, i, 330; breeding of, true, x, 195; classification of, 195; destruction by disinfectants, viii, 332-3; destruction in blood, x, 209-11; disease-making (see Disease Germs); fermentation by, ix, 248; flowerless plants, xiii, 13; food of, ix, 27, 248; in air, i, 61; Chicago standards, viii, 332; in body, x, 201-2, 204; in intestines, ix, 247-9; in sea, xii, 16; Leeuwenhoek's studies, xvi, 107-8; low temperature effects, i, 32; luminous, 346, 349, xii, 20; nitrogen fixation by, i, 35, viii, 340, 345, 346, x, 193-4, xiii, 98, xiv, 66; number of species, xiii, 323; origin of, xii, 12; Pasteur's studies, xvi, 143; preserving foods against, viii, 372; sewage treatment by, 325, 327-9; single-celled, xiii, 166; size, i, 61, xiii, 63; soil, xii, 15; ultramicroscopic, x, 200; useful forms of, 193-4 Bacteriemia, x, 220 Bacteriology, x, 194; foundations of, 143, 196 Badgers, xii, 347-8 Bad Lands, iii, 139-40, 230, xiv, 62, 81-2 Bagehot, quoted, xvi, 198 Baglivi, x, 76, 77-8, 155 Bag-pipes, xv, 317 Baguio, Philippines, rainstorm at, 1, 110 Baguios, i, 136, 367 Bahamas, hurricane grass of, xiii, 344; sisal production, 240; wild fig tree, 18 Baikal, Lake, depth of, xiv, 204; in rift valley, 123 Bailey's Beads, ii, 87 Baking Powders, viii, 136-7, 223 Baking Soda, viii, 135-6, 146, 278 Balance, sense of (see Equilibrium Sense) Balanced Forces, v, 183-6 Balance Levers, v, 63-4 (fig.) 65 Balance Spring, invention, v, 65 Balance Wheels, v, 68-9, 71-2 Baldness, ancient treatment of, x, 12; hats and, 309 Balearic Basin, xiv, 291 Balfour, Francis, x, 131 Ball-bearings, iv, 93, v, 206 Ballistic Wind, i, 313-67 Ball Lightning, i, 149-52, vii, 205-6, 213-15; as ignis fatuus, i, 347 Ballon-sonde, i, 21, 367 Balloons, iv, 107-8, v, 219-30; aerological uses and kinds, i, 18, 19, 20-2, 89, xvi, 177; dirigible (see Dirigible Balloons), heights attained, i, 18, 22, 303, v, 225; hydrogen in, iv, 108, viii, 33; sounds heard, i, 188; why they rise, 286, v, 221-2 Baltic Provinces, coasts of, xiv, 247 Baltic Racial Group, xvi, 48-9 Baltic Sea, development of trade of, xiv, 308; formation of, 287; green color, xvi, 147; salt in, viii, 139, xiv, 296 Baltimore, harbor of, xiv, 268 Bamboo, in grass family, xiii, 179, 181; rapid growth, 358; stem, 26, 183; tropical wood, xiv, 383 Banana, xiii, 216-18; calories in, ix, 299; flavor and odor, to what due, viii, 221; food value, 365, x, 266-8; in tropical forests, xiv, 368 Banana Oil, viii, 214, 221, 251 Bandai-san, eruption of, xiv, 324 Banks, oceanic, xiv, 286 Banyan Tree, xiii, 16 (illus.), 21 Bar, pressure unit, i, 70, 367 Barbados, overpopulation of, xiv, 282 Barbed Fruits, xiii, 58 Barbers, as surgeons, x, 35, 41, 54, 105, xvi, 181 Barberry Bush, xiii, 128-30 Barisal Guns, i, 195, 367 Barite, iii, 323; gangue mineral, viii, 199 Barium, viii, 148; affinity strength, 128; atomic weight and symbol, 383; flame color, 301; fluorescence of, vii, 254; specific gravity, viii, 384; test for, 287-89 Barium Chloride, viii, 290, 301 Bark Lice, xii, 112 Barker, Dr., quoted, x, 375-6 Barley, composition and value, viii, 364; malt from, 249; ripening time, xiv, 365; source, 382; vitamines in, x, 262 Bar Magnets, iv, 242-3, 250, vi, 30-4 Barnacles, xii, 82, 84-5 Barns, electricity for, vii, 227-8; lightning rods on, i, 156 Barocyclonometer, i, 280, 367 Barographs, i, 71-2, 367 Barometers, i, 70-2, 367, iv, 119-24; Torricelli's development of, i, 68, iv, 29, 30, 114, xvi, 109, 177 Barometer Wells, i, 354, 367 Barometric Gradient, i, 126, 373 Barometric Pressure (see Atmospheric Pressure) Barometric Tendency, i, 71-2, 367 Barotaxis, xi, 53, 61 Barramunda, xii, 154, 165-6 Barrel Gears, v, 27-8 Barrier Reefs, xii, 40-1, xiv, 263 Barton, Prof. W. M., author Medicine, Volume x Bars, vibration rate of, iv, 223-4 Basal Metabolism (see Basic Metabolism) Basaltic Lava, defined, iii, 377; in Grand Canyon, 177; jointing in, xiv, 129-30; soils from, iii, 28 Basalt Rock, magnetized by lightning, i, 152-3 Base, Bases (chemistry), viii, 374; defined by ionization theory, 122; electrolytes, 125; formation and character, 20, 39, 115, 117-18; ionization in solution, 119-25, 300-1; litmus effect, 114; production, 276 Baseball, pitching of curves, iv, 67-9 Baseball Games, crowd psychology at, xi, 327; value to spectators, 139-40 Baseball Players, sensory type, xi, 156 Base Level of Erosion, defined, iii, 30, 377, xiv, 40; form of rivers at, 49; of waves, 254 Base Plugs, vi, 276-7, vii, 72 Basic Metabolism, ix, 37, 78, x, 271; daily amount in calories, ix, 296, x, 271; disease effects on, ix, 302-4, x, 272; heat production by, ix, 307; of obese persons, x, 274; protein stimulation of, ix, 301-2; protoplasmic wastage by, 282-3; temperature and water effects, 37-8 Basilar Membrane, of ear, iv, 203 Basin Ranges, formation of, xiv, 117 Basins, ocean, xiv, 286 Basket Fish, xii, 49 Baskets, Indian, xv, 248 Basques, isolation of, xv, 130 Bathrooms, lighting of, vii, 71-2 Baths, Bathing, ix, 313, 321-2, x, 311-12; need of, after exercise, x, 304; therapeutic uses, 311, 383; warm for insomnia, xi, 289-90 (see also Cold Baths, Hot Baths) Bats, xii, 369-72; in oceanic islands, xiv, 277 Batteries, electric (see Electric Batteries) Battles, crowd psychology in, xi, 326-7; rain from, i, 336-8 Battleships, electrical applications (U. S. N.), vii, 325-35; gun-training on, v, 104; importance, vii, 325-6; radio directing of, 284; wireless telephony and, 281-3 Bauxite, iii, 369; in basic refractories, vii, 307 Bayberry Bush, xiii, 191, 341 Bayliss, hormones discovery, x, 320; secretin discovery, 325; quoted, xi, 198-9 Bays, in irregular coasts, xiv, 252; of ria coasts, 257 Beach, Alfred E., v, 138 Beach, Prof. Robin, author Electricity, Vols. vi, vii Beaches, amphipods of, xii, 85; features of, xiv, 246; formation of, iii, 58, 81; plants of, xiii, 381-2; raised, iii, 81, xiv, 209; rapid development of, iii, 58 Beach Fleas, xii, 81-5 Beach Walls, xiv, 246 Beachworms, xii, 54 Beaded Lightning, i, 149 "Beagle," voyage of, x, 134-5, xiv, 142 Beam Balance, iv, 101-2 Beam Warpers, v, 280 Beans, as food, viii, 365, ix, 34, 36, 299, x, 262-79; food-obtaining devices, xiii, 97; leaves, 36-7, 113; movement of tendrils, 111; in pea family, 198; origin, 222; petals, 47; seeds, 56; seed-leaves, 176 Beards, as race character, xv, 38 Bears, xii, 336-8; canine teeth in, 333; first cave-dwellers, xv, 206; in Great Britain, xiv, 273 Beasts of Prey, xii, 332-65 Beats (sound), iv, 219-20, vii, 279 Beaufort Scale, i, 84, 367 Beaumont, William, ix, 240, x, 121, xvi, 186 Beauty, universal appreciation of, xvi, 145-6 Beaverdam Creek, iii, 38-9 Beaver-dam Lakes, iii, 157 Beavers, xii, 295-6; first lumberers, xv, 206 Beckel Process, v, 287-8 Becquerel, Henri, xvi, 193 Bedbugs, xii, 114; ancient, 104 Bedded Rock (see Sedimentary Rock) Bedford Limestone, iii, 371-2 Bedrooms, air of, xi, 285; furnishings and sleep, xi, 290; lighting of, vi, 275-6, vii, 71 Beds, right, for sleep, xi, 290 Beebread, xiii, 124 Beech Forests, carbon used by, i, 14; of Chile, xiv, 371; of Denmark, xv, 86-7; water requirements of, xiv, 377-8 Beech Trees, family, xiii, 193; in landscaping, 271-2; leaf-bud protection, 34; of U. S., 368, xiv, 372 Beef, calories in, ix, 299; proteins in, 279; vitamines in, x, 262 Beef Extracts, value, viii, 362 Bees, xii, 125-6; appearance in Tertiary, 104; jaws and maxillæ in, 100; plant visitors, xiii, 123-4, 126-7, 128-30, 137-9 Beeswax, viii, 221-45; melting requirements, iv, 162 Beetles, xii, 121-4; appearance of, 104 Beets, antiscurvy vitamines in, x, 266; origin and antiquity, xiii, 222; sugar storage in, ix, 27-8; swelled roots, xiii, 19 (see also Sugar Beet) Beet Sugar, viii, 226-7, 242, xiii, 216; compared with glucose, ix, 230 Beginners' Luck, xi, 253 Begonias, coloring of leaves, xii, 42; reproduction, 165-6 Beheaded Streams, xiv, 182-3 Behel, Jacob, v, 248 Belgians, in Alpine group, xvi, 49 Belgium, fossils found in, iii, 292; German invasion, reasons, xiv, 91-2; low elevation, 247; mistpoeffers, i, 195; tobacco consumption, xiii, 256; topography of, xiv, 86 (map), 90-1; zinc production, iii, 364 Bell, Alexander Graham, telephone invention, vii, 92, xvi, 188 Bell, Charles, x, 117 Bell, John, x, 129 Bell, Rev. Patrick, v, 246 Bell-crank Levers, v, 24-5 Belle Isle Strait, proposed damming, i, 345 Bells, vibrations of, iv, 221-2 Bell Telephone System, vii, 92; automatic telephones, 106 Benedictine Order, medical work of, x, 36 Benguella Current, xiv, 305 Ben Nevis, rime growth, i, 122; St. Elmo's Fire, 158 Benz, Karl, v, 213 Benzaldehyde, viii, 239 Benzene, viii, 51, 234-5, 374; derivatives, 236; from coal tar, 253; freezing and melting points, iv, 163-4 Benzene Hydrocarbons, viii, 206, 232-6; derivatives, 236-40; products, 52, 241, 258 Benzene Ring, viii, 233, 234, 240 Benzine, viii, 234-5 Benzoic Acid, viii, 236, 239, 372 Benzol, viii, 234-5 Benzyl Alcohol, viii, 239 Benzyl Bromide, viii, 263 Berea Sandstone, iii, 372 Berengario of Carpi, x, 52, 60 Bergman, chemist, xvi, 119, 120, 174 Bergshrund, iii, 66 Bergson, philosophy of, xvi, 196 Beriberi, ix, 35-6, x, 257-9, 264; cause of, viii, 369; racial susceptibility to, xv, 50-1 Bering Sea, seal breeding in, xii, 334 Bering Strait, xiv, 22 Berkshire Hills, formation, iii, 188, 190 Berlin, sewage disposal, viii, 327 Berliner, Emile, gramophone, v, 328-9, 382; transmitter, 381 Bermudas, climate of, xiv, 370-1; coral reefs of, xii, 40 Bernard, Claude, x, 127-8, xvi, 185-6 Berries, xiii, 54; poison in wayside, 252 Berson, balloon ascension, i, 18, v, 225 Bertrand, Alexandre, xvi, 185-6 Beryl, iii, 324-5 Berzelius, Jacob, xvi, 160-1, 165; on fermentation, x, 138 Bessel, dismissal from Greenwich, xi, 156; instruments and methods, ii, 16, 55; on genius and instruments, 93; prediction of, 124; study of stellar parallaxes, 311-12, 313 Bessemer Converter, v, 319, 320, 322, 380, viii, 159; invention, xvi, 175 Bessemer Steel, ore for, iii, 356 Besson, Dr. Louis, i, 181; nephoscope, 86, 85 (fig.) Beta Aurigæ, ii, 123 Beta Rays, i, 143, viii, 185 Betelgeuse, angular diameter, ii, 151, 322-3; chemical study of, 114; color, 297; name, 39 Betel Nut, xiii, 254-5 Bevel Gears, v, 30-1; primitive, 27-8 Beverages from various plants, xiii, 213, 219, 227-35 Bharal, xii, 326 Bianchini, ii, 99, 227 Bias, psychological effects, xi, 103, 208-9, 216 Biberthal, Switzerland, xiv, 186 Bible, account of man in, xv, 69; Anglo-Saxon passage from, 157; emotions depicted in, xi, 131; "Great Sea" of, xiv, 358; rice and sugar not mentioned, xiii, 214-15; weather proverbs, i, 67 (see also New and Old Testaments) Bicarbonate of Soda, medical uses of, x, 12, 322 Biceps, ix, 76-7 (fig.) Bichat, x, 117 Bicycle Pump, i, 26-7 Bicycle Races, energy expenditure in, ix, 297 Bicycles, equilibrium maintenance on, iv, 62; gyroscopic action, v, 343; pedal invention, 380; riding of, ix, 155-6, 158-9 Biela's Comet, ii, 280, 286 Biennials (plants), roots of, xiii, 16, 18 Bifocal Lenses, ix, 112; invented by Franklin, x, 104 Big Creek Power Plant, v, 79, 81 Bigelow, Henry J., x, 125 Big Horn Sheep, xii, 326 Bigourdan, astronomer, ii, 358-9 Big Trees, Californian, age and size, xiii, 26; branches, 86; climatic changes seen in rings, i, 199, 200, xiv, 362; former wide distribution, iii, 256, xiii, 352 (see also Sequoias) Bihar, India, hailstorm, i, 120 Bile, ix, 237, 243, 275-6, x, 325-6, 329-30 Biliousness, x, 330 Billfish, xii, 152 Billings, John Shaw, xvi, 186 Billroth, Theodor, xvi, 183 Binary Stars, ii, 122-4, 334-5; distance, 319-20; orbit eccentricity, 377; origin, 378-9; periods, 319; relation to Galaxy, 327; variability, 326-7 (see also Double Stars) Binding Machines, v, 247-8 Binoculars, principle of, xi, 180 Binomial Nomenclature, x, 84 Binturongs, xii, 353 Biochemistry, viii, 205, 348 Bioclimatic Law, i, 256, 367-8 Biology, defined, xvi, 36, 42; history of development, 118, 142, 144-58; medicine and, x, 369; modern, due to Darwin, 134-6; remarks on science of, 368 Biometry, science of, xvi, 153-8 Biot, balloon flights, i, 18; meteor studies, ii, 284-5 Biotite, iii, 334 Birch Trees, antiquity of species, xiii, 324-5; family, 193; fertilization, 148; in landscaping, 271-2; seed dispersal, 343; in U. S., 368, xiv, 372 Bird-catching, by Australians, xv, 224 Bird-catching Spiders, xii, 97 Birds, xii, 239-69; anatomy of, 239, 247-8; appearance in eocene, xv, 71; care of young by, 275-6; carinate, xii, 250; colors of, 245-6; courtships of, xv, 274-5; embryological resemblances, 54; evolution, iii, 286, 295-7, xii, 195, 239-43; eyes of, xi, 98; fear in, 136; feathers of, xii, 243-7; flower fertilization by, xiii, 123; food of, ix, 24; game, xii, 261-3; heart of, x, 332; infectious diseases of, 206; luminous, i, 346-7; man's lessons from, xv, 206; migrations, cause, xiii, 55; monogamy of, xv, 276-7; oil-secreting organ of, x, 310; orders of, xii, 249; passerine, 268-9; phosphorus in excrement, xiv, 68; protective coloration in, xv, 17; ratite, xii, 243-49; ribs of, 184; seed dispersal by, xiii, 55, 58, 59, 340-3; sense of smell, xi, 78; singing of, iv, 209; singing organs, xii, 248-9; sleeping habits, xi, 287; teaching of young to fly, xv, 66, 275-6; temperature regulation in, ix, 306, 307, 308; used in hunting and fishing, xv, 223-4; various groups, xii, 264-7; warm-bloodedness of, ix, 305; water, xii, 250-9 Birds of Paradise, courtships of, xv, 275; plumes of, xii, 244 Birds of Prey, xii, 260-1 Birmingham Iron Region, iii, 358-9 Birs River, Jura Mountains, xiv, 94 Birth, ix, 344; body conditions and development at, 345-52; bones at, 58; freedom from germs at, x, 201; heart rate at, 334, ix, 347; muscle cells at, 48, 348; skull capacity at, xv, 40; temperature changes at, xi, 36-7; weight at, ix, 31 Births, male and female, ix, 340 Biscay, Bay of, depths, xiv, 289; sand destruction in, iii, 75 Bishop's Ring, i, 58, 183, 368 Bismarck, skull capacity, xv, 40 Bismuth, affinity strength, viii, 128; atomic weight and symbol, 383; expansion on solidifying, iv, 150; in Rose's fusible metal, 162; melting point, viii, 384; melting point, pressure effects on, iv, 163; occurrence, viii, 131; specific gravity, 384; tests for, 287-8 Bisons, xii, 329-30; formerly in Europe, xv, 76; pictured in Cro-Magnon art, 114-18 (fig.) Bitter, taste of, ix, 95, xi, 70, 71, 72 Bitterns, xii, 254-5 Bituminous Coal, beds in U.S., iii, 200-1, 346-7, 348; elements, 345; per cent carbon in, viii, (see also Soft Coal) Bituminous Strata, origin, iii, 249-50 Bivalves, xii, 58, 63 Black (color), absorption of light by, iv, 364, x, 309; produced by interference of lights, iv, 377-8; sensation of, ix, 115 Black, Joseph, chemical work, xvi, 119-20, 125, 177; discovery of respiration physiology, x, 88-9 Black Beetles, xii, 107 Blackberry, aggregate fruit, xiii, 55; in rose family, 197; origin, 224; running, 28 Blackbirds, xii, 269 Black Death, x, 163-4 "Black Earth," of Russia, xiv, 217 Blackfish, xii, 297 Black Forest, Germany, xiv, 238-9; geology of, 87 (map), 90, 117, 128 Black Hills, xiv, 93, 227; core of, 111; former forests of, 373; mineral springs of, 145 Black Hole of Calcutta, i, 321, ix, 268, x, 238 Black Lead, iii, 331, viii, 43 (see Graphite) Black Lightning, i, 148 Black Powder, viii, 144-5, 260 Black Race, xv, 32; brain and skull capacity, 41; disease immunity and susceptibility, 48-9, 50-1; facial angle in, 45; fitted to tropics, 50; jaw angle, 44; nose index and nostril shape, 46; peoples, 37; separate origin theory, 69, 70; skull shape, 42; type characters of, 35 Black Sea, hanging valleys on shore of, xiv, 58; importance of ports, 267; salinity of, 296, viii, 139; sturgeons of, xii, 152 Blacksnakes, xii, 218-19, 229 Blair, Henry, xvi, 187 Blanc, Mount, observatory on, ii, 142-9; "resurrection," i, 168; sound intensity on, 186 Blankets, warmth of, iv, 178 Blast Furnaces, v, 317-18; air blast of, viii, 158; ancient Egyptian, xvi, 74; carbon uses, viii, 157; cooling of air for, v, 347; development of modern, 315-16, xvi, 174, 175, 176; oxygen in, i, 33; potash from dust, viii, 279 Blasting, v, 261-2; explosives for, viii, 260; with compressed air, i, 27; with water, v, 100 Blasting Powders, viii, 137-8 Bleaching, chemistry of, viii, 86; chlorine, 85-6; hydrogen peroxide, 41, 86; ozone, vii, 354; sulphur dioxide, viii, 78, 146; of wool, 256 Bleaching Powder, viii, 86-7, 146, 153, 274 Bleeders, Bleeding Sickness, ix, 181; transmission of, x, 234 Bleeding, from arteries and veins, x, 39; leeches used for, xii, 55; stopping of, ix, 179-81 Blended Inheritance, ix, 334, x, 230-1; in animal and plant breeding, ix, 337 Blériot, flight of, i, 43 Blight, cause of, xiii, 71 Blind, optophone reading for, v, 332, 334-5, 384; space perception by, xi, 168-9 Blindness, black seen in, ix, 116; cause, xi, 96-7; from brain disease, ix, 146; from cataract, 112 Blind Spot, xi, 87-9 Blish, Commander, v, 367-8 Blizzards, i, 133-4, 368; device against, 345 Block and Tackle, v, 34-5 Block Mountains, iii, 138-9, xiv, 117, 226 Block Signal Systems, v, 211, vii, 355-9 Block Tin, viii, 161 Blood, absorption of digested food by, ix, 226, 243-6; adrenalin effects, 171-2, xi, 137-8; aeration of, by lungs, x, 62, 331; amount in circulation, 337; anemia, 337; arterial, ix, 260, 263, 264; carbon dioxide in, 190, 262-3; effects, 264-7, x, 339; carbon monoxide effects, viii, 50-1; circulation of (see Circulation of the Blood); clotting of, ix, 180, x, 88, 337; coagulation after emotion, xi, 138-9; coloring matter related to Chlorophyll, xii, 14; color of, in relation to oxygen, ix, 259-61; composition, 173-90; control of vital processes by changes in, 168-72; conveyer system, 191, 225; corpuscle-forming tissues, growth of, 287; distribution efficiency, x, 238-9; emergency emotion effects, ix, 166, 171, 293, xi, 136-7; fats in, ix, 289; flow, how controlled, 215-16, 219-21; functions, summarized, 50-1, x, 331-7; germ destruction by white corpuscles, 197, 209-11; in embryo, ix, 343; interchange with tissue, fluids, 51 (fig.), 191, 193-5, 221-2; iron and salts in, uses, viii, 354; liver action on, x, 329; maternal influences through, ix, 343-4; mountain-sickness effects, i, 328; neutrality or alkalinity of, x, 280-1; oxygen supply and transportation, ix, 182-3, 198-9, 253-62, x, 338-9; platelets of, ix, 188-9; proteins of, 176-7, 194-5, 262-3; rate of passage through heart, 210, 211, 212; red corpuscles, 181-4 (see Red Corpuscles); renewal of, 173; sensations, effect on, xi, 68; sleep effects, 283-5, 289; soul in, Greek idea of, xv, 330; sugar in, regulation and excess, ix, 290-3, x, 329, 330; sugar increase in excitement, xi, 138; temperature, v, 348-9; temperature rise, effects, ix, 169, 315-16; transfusion of, x, 337-8; venous, ix, 263-4; waste removal by and from, 271-6; water absorption and supply, 247; white corpuscles, 182 (fig.), 184-8 (see also White Corpuscles) Blood-destroying Germ, x, 221 Blood Heat, i, 319 Blood Pressure, ix, 213-20, x, 334-6; color effects, xi, 63, 96; in sleep, 283-4 Blood Rains, i, 358 Blood Suckers, x, 91 Blood Vessels, ix, 191-3, 196-8; classes and disorders of, x, 334-6; climatic effects on efficiency, 238-9; control of caliber of, ix, 161, 168, 215-16, 219-20, 311; functions of, 50-1; injuries, how mended, 180 Blooms, iron and steel, v, 317, 322 Blowers, electric, vii, 86 Blow Guns, xv, 216-17 (fig.) Blowing Wells, i, 353-5, 368 Blowout, magnetic, vii, 37-9 Blue, complementary color of, iv, 367; in birds' feathers, xii, 245; in interior decoration, vi, 274; of sky, i, 165, penetration of ocean by, xii, 22; wave length of, iv, 365 Blueberries, xiii, 202, 224 "Blue Coal," v, 174 Blue Columbine, xiii, 126-8 Blue-grass Region, xiv, 68 Blue Grotto of Capri, iii, 81 Blue Gum Trees, xiii, 26, 94, 350; leaves of, 106; swamp draining by, xiv, 379 (see also Eucalyptus) Blue Ridge Mountains, metamorphism in, xiv, 234 Bluffs, formation of, xiv, 84 Blunderbuss, v, 361 Boa Constrictor, xii, 215 Boas, family of, xii, 213, 215-16 Boats, evolution of, xv, 261-3; propulsion of, 265 Bobcats, xii, 364-5 Bode's Law, ii, 254-5 Bodies, of matter, defined, iv, 12, 381 Body, anatomy and physiology of, ix; care of against fatigue, xi, 279-80; care of, instruction in, x, 282-5; changes in, untransmitted, ix, 326; chemical composition, viii, 348, 349, 353, 354-5; construction features and units, ix, 12, 13; dissection of, x, 30, 41-2, 45, 81; efficiency of, viii, 367, ix, 306, x, 238-9; electrical conductivity, iv, 259; electricity effects, vii, 246-9, xi, 117; emergency responses of, ix, 166-7, 171-2, 209, 220, 221, 293; exercise effects, x, 303-4; fatigue conditions, xi, 270-4; fatigue results on resistance, x, 248; food needs and utilization, (see Food); functional disorders, x, 318-65; functional regulation, 346-7, 352-3; functions, chemical explanation of, xvi, 142; functions, close connection of, xi, 31; growth of (see Growth); hair on, xv, 38; hardening processes, x, 240; infection portals, 198, 201-2; kinetic system, xi, 57, 60-1; living and nonliving parts, ix, 12, 13, 31; machine parts suggested by, v, 20; mechanisms of, 248; metabolism (see Metabolism); mind and, relations, xi, 13, 14, 61, 369-75; motions, different kinds, ix, 82-3; mutilations among savages, xv, 257-60; painting of, 255-6; poisonous effluvia of, ix, 269-70; positions of, in relation to health, x, 241-2 (see also Postures); pressures, xi, 53; pressure of atmosphere on, i, 23; proper clothing of, x, 306-10; regulation to environment, 249-51; reproduction from cells, ix, 324-5, 332-3; resistance to disease germs, 177-9, 185-6, x, 203-12, 240, 248, 289, 292; salt requirements, ix, 174; seat of life in, 11, 12, 17; shame of, xv, 254-5; temperature, v, 348-9, ix, 306-7, 312, x, 250-1, 306; temperature after hard work, ix, 317; temperature equality, advantages of, 78-9; temperature in different scales, iv, 137 (fig.); temperature in fever, ix, 317-19; temperature regulation, i, 316-17, 320-1, 322, v, 348-9, viii, 331, ix, 169, 305-23, x, 310; temperature rise from excitement, xi, 140; temperature rise in dense atmosphere, iv, 31; tissues (see Tissues); unstable chemical organization, xi, 134; wastage and repair of, ix, 278-86; waste elimination in tropics and cold climates, xv, 49, 50; water functions in, viii, 355-6, wonders of, vi, 272; X-ray effects, vii, 250 (see also particular parts and functions) Body Cells, ix, 13, 41-3, xi, 15, 17, 49; development of, ix, 43-8, 324-5, 332-3; different kinds, 13, 39, 42-3, 277, 329; living and nonliving, 12-17; maintenance and growth, 34-6, 38-9, 189, 278-84, 287-9; metabolism of (see Cell Metabolism); oxygen needs and supply, 182, 199, 253, 254, 260; power development in, 16, 17, 22, 36, 40; salt needs, 174; size of, 12; sugar and fat supplies, 289-91; supply and renewal system, 49-52, 193-5, 221-2, 262, 271; supporting tissue, 71-2; waste of, in starvation, 298; X-ray effects on, vii, 253 (see also Muscle Cells, Nerve Cells, Germ Cells, etc.) Body Fluids, ix, 50-1, 173-90; in connective tissues, 59; sugar in, 290, 291 (see also Blood, Tissue Fluids) Boë, Francis de la, x, 69, 70, xvi, 108 Boerhaave, Hermann, x, 76-7, 87, xvi, 112, 178 Boer War, kopjes in, xiv, 82 Boethius, xvi, 101 Bog Iron Ore, iii, 13, viii, 156 Bog Mosses, xiii, 68-9 Bogoslof Islands, xiv, 319 Bog Plants, xiii, 104, 381-2 Bogs, formed from filling lakes, xiv, 210-12 Bohemian Glass, viii, 281 Boiler Explosions, caused by electrolytic corrosion, vi, 64-6; due to scale, xiv, 147; violence, v, 140 Boilers, Steam, v, 139-42; boiling point of water in, viii, 303; hard water in, 151-2, 323, xiv, 147; heat loss, v, 155; pressure in, iv, 119, 170 Boiling, of foods, xv, 233; of liquids, iv, 167-75 Boiling Point, iv, 168; chemical composition and, viii, 298, 301; in various thermometers, i, 73, iv, 136, 137, 141, viii, 27; of various substances, iv, 173; pressure effects on, 168, 169-70, v, 354, viii, 303-5 Boils, causes of, ix, 186, 187, x, 195, 201, 311 Bolivia, Chilean control of, xiv, 306 Bologna, University of, xvi, 100; medical school of, x, 38 Bolometers, iv, 301, vii, 363; in corona studies, ii, 212, 225 Bombay Duck, xii, 163 Bombing Machines, v, 233 Bombs, aerial, v, 372-3 Bombs, volcanic, xiv, 323 Bond, Dr. A. R., author Mechanics, Vol. v Bonds (chemistry), defined, viii, 374 Bone Black, viii, 47 Bone Fertilizers, viii, 153, 280, 343 Bones, of body, ix, 59, 71; cartilage beginnings of, 58; condition of, in infants, 345-6; food needed for, 33; formation, structure, and growth, 54-7, 58; inflammations of, x, 224; lime salts in, ix, 57; red marrow of, 183; used in hearing, iv, 204; X-ray pictures of, iv, 320, vii, 253-4, 255 Bonneville, Lake, iii, 153 Books, ancient making of, xv, 178-9; printing and binding of, v, 306 Book Scorpions, xii, 90 Boomerangs, xv, 194, 208; principle of, iv, 42 Bora Winds, i, 133, 368 Boracic Acid, viii, 89, 90, 372 Borates, preparation, viii, 117; test, 290 Borax, composition, viii, 141; deposits, 89, 90, 197, 275; uses, 89, 141, 146, 333, 372 Boredom, in work, xi, 275-6, 277-8, 280 Borelli, Giovanni Alfonso, x, 70, 71-2, 83 Boric Acid, natural sources, viii, 90, 118; preservative, 89, 333, 372; solid, 114 Boring Machines, v, 44, 376 Boring, deep, xiv, 11, 12 (see also Wells) Borneo, continental island, xiv, 274; coconut gathering in, xii, 378; orang-utan of, 381; rhinoceros of, 306; sun bear, 337; tattooing in, xv, 259; tribal morality in, 374 Boron, viii, 19, 89, 90; atomic weight and symbol, 383; in silicates, 193 Bosphorus, importance to Russia, xiv, 267 Boston, drumlins near, xiv, 60; harbor of, 269; sewage disposal, viii, 326; water supply, 317, xiv, 140 Boston Ivy, xiii, 28 BOTANY, Volume xiii Botany, xvi, 36; binomial nomenclature in, x, 84; daily interest, xvi, 20-2; discovery of America, effects, x, 45; history of development, xvi, 112, 116, 165-7; public education in (France), 22 Bothnia, Gulf of, salinity, xiv, 296 Bow-and-Arrow, evolution of, xv, 213-15; fish-shooting with, 227; stringed instruments developed from, 317-18 Bowditch, Henry Pickering, x, 131 Bowels, care of, x, 316-17; "yearning of," xi, 64, 131, 160 (see Intestines) Bowfin, xii, 152; nests of, 154 Bowlder Clay, iii, 67, xiv, 59 Bowlders, glacial, iii, 70, 237, 352 (pl. 20), xiv, 69, 70 Boyle, Robert, air pressure experiments, iv, 29, 125; chemical work, xvi, 110, 111, 112, 115, 119, 177; "Sceptical Chemist," quoted, 159 Boyle's Law, iv, 125-6, 133, 143, 156, viii, 106-7 Boys, education of, xi, 266-7; food consumption by, viii, 367 Brachiopods, iii, 259, 263, 270-2, xii, 47-8; deep sea 23; illustration, iii, 256 (Pl. 14) Bracken Fern, xiii, 350 Bracts, xiii, 43, 45, 206 Bradley, James, astronomical work, ii, 90-2, xvi, 124 Brahe, Tycho (see Tycho Brahe) Braided Goods, v, 276-7 Brain, ix, 131, 144-7, xi, 15-32, 60; areas for different functions, xv, 89-90; as seat of life, ix, 11, 14, 17; association fibers, xi, 200; association region of, ix, 151; auditory area, xi, 108; blood supply of, ix, 197, 216-17; cells of, 14; changes caused by shock xi, 59; condition of, at birth, ix, 351; connections in nervous system, 142-4, 147-51; convolutions of, xv, 62-3; delayed nervous impulses in, ix, 140, 141-2, 145, 146-7; diseases, results of, 146; emotional processes in, 154, 200; gray matter of, xv, 63; in dreams, xi, 301; in sleep, ix, 218, xi, 285, 286, 287, 289; inflammation of, cause, x, 224; insensitive to pain, xi, 118; intellectual processes, ix, 147-53, 154; magnetism effects, vii, 247; mental incapacity from defects, xi, 13; motor area, ix, 147; of insects, xii, 103; of men and lower animals, compared, xv, 62-3, 96; of primitive men, iii, 302-3, 304, xv, 89-91, 96; various animals of past, iii, 289, 290, 292, 298, 299; overuse effects, xi, 288-9; protection of, in infants ix, 345; Sherrington on, xi, 12; skull capacity in relation to, xv, 41; stomach and, relations, xi, 370; storehouse of past environment, 58; tissues unaffected in starvation, ix, 298; visual area, xi, 96-7; waste of energy of, 377; weight in man and apes, xv, 62; weight in various men and races, 39-41; wounds of, early treatment, x, 55, 56 (see also Brain Stem, Cerebellum, Cerebrum) Brain Case, ix, 61; face and, xv, 43, 62 Brain Power, development of, in man, xv, 190-1; racial expressions and, 39, 63-4 Brain Stem, ix, 144-5, 146 (fig.); vital process centers of, 167-9, 257, 315 Brain Work, energy consumed by, viii, 367; fatigue from, ix, 138, x, 247 Brain Workers, ailments, xi, 371; attractive foods for, ix, 242; exercise needs, x, 304 Brakes, air (see Air Brakes); electromagnetic, vi, 92, 94; friction, iv, 93-4; regenerative, vii, 200 Bramah, Joseph, hydraulic press, v, 98-9, 376; planer, 377 Bran, in diet, x, vitamines in, 261, 266 Branches of Trees, as leaves, xiii, 378, 379; why clear of ground, 86 Brandes, H. W., i, 215 Brasher, Philip, v, 124-5 Brass, alloy of copper, viii, 156, 164, 273; electrical conductivity, iv, 283; electric welding of, 312; expansion and contraction of, 145-6, v, 72 Brave West Winds, i, 128, 368 Brazil, bushmaster snake of, xii, 234; butterfly orchid of, xiii, 145; coasts, xiv, 257; coffee production, xiii, 232, 233; coral reefs on coast, xiv, 305; forests, xiii, 365, xiv, 366; frogs of, xii, 178, 179; glacial and coal deposits, iii, 203, 204; interior unexplored, xiv, 26, 250; jaguarundi of, xii, 364; lizards of, 208; matamata of, 193; public health scholarships, x, 172; rubber production, xiii, 246-7, 248; shirt tree of, xv, 256; soil depths, iii, 26; tea cultivation, xiii, 228; wolf of, vii, 342; yellow fever in, x, 163 Brazilian Basin, xiv, 289 Brazilian Current, xiv, 304 Brazil Nut, source, xiii, 266 Bread, chemistry of, viii, 368-9; digestion of, x, 326; food value of, viii, 364, ix, 34-5, 299, x, 267, 268, 269, 273; rising of, due to bacteria, 194; yeast action in, ix, 248 Breadfruit, origin, xiii, 224 Breadfruit Trees, xv, 124 Breakwaters, pneumatic, v, 125; strength of, xiv, 300, 301 Breath, holding of, ix, 256-7, 266; holding of, in infants, 348; shortness of, in heart failure, x, 340-1; smell of, ix, 97; soul in, savage idea of, xv, 330 Breathing, action and control of, ix, 256-8, 263-6, x, 339; body heat regulation by, 251; color effects on, xi, 96; deep, value of, ix, 259; deep, sensations from, 266-7; how learned, xi, 36-7; in fatigue, 272; in sleep, 283; muscles of, in voice production, ix, 83; of insects, xii, 103; periodic, x, 339-40; quickened by exercise, 303; rate of, in infants, ix, 347-8; rib cage movements in, 65; through mouth, effects, x, 341-2 (see also Respiration) Breeding (animal and plant), blended inheritance and pure breeds, ix, 337; in ancient Egypt, xvi, 72; in captivity, xv, 197; selective, ix, 327, xvi, 157-8 Brennan, Louis, v, 342 Brenner Pass, xiv, 240-1 Bretonneau, Pierre, x, 106, 110 Brewing, chemistry of, viii, 249 Bricks, invention of, xv, 268; making of, in Egypt, 267 (fig.) Bridges, steel, electrolysis in, vi, 64, 66; strains on, v, 194; sympathetic vibration of, iv, 225 Briggs, Henry, xvi, 104 Bright's Disease, x, 112, 225, 335, 340-1, 345, 346 Bristol Channel, tides of, xiv, 293 British Columbia, fjord coasts, xiv, 258; no volcanoes or earthquakes in, 315, 331 British Gum, viii, 243 British Meteorological Office, i, 222; aeronautical service, 230, 286; forecasts, 241; in World War, 310 British System of Units, iv, 46, 69-70, 79, 80 British Thermal Unit, iv, 154, v, 350-1; erg and calorie equivalents, vii, 382 Brittle-stars, xii, 23, 49 Broadway, N. Y., display lighting vii, 340-1 Broca, Paul, x, 130 Brocken Specter, i, 184, 185, 382 Bromine, a halogen, viii, 18, 84; atomic weight and symbol, 383; manufacture, 274; properties and uses, 84-5, 86, 181, 297-8, 333; test, 290 Bronchial Tubes, as infection center, x, 220, 224; defence against germs, 202; subdivisions of, ix, 255 Bronchitis, causes, x, 253, 295 Brongniart, Adolphe, 167, 169 Brontides, i, 195-6, 368 Brontosaurus, xii, 195 Brooklyn, water supply of, xiv, 140 Brooklyn Bridge, completion, v, 382; corrosion of, vi, 66 Brooks Comet, ii, 134, 275, 286 Brook Trout, xii, 159 Broths, viii, 362, 369 Brounov, Prof. P., i, 249 Brown, John, medical work of, x, 89-90 Brown, Robert, xvi, 166 Brownian Movements, viii, 314, xvi, 166 Browning John M., v, 363, 366-7 Browning Machine Gun, v, 366-7, 384 Brown Paper, making of, v, 294; source, xiii, 240 Brown Race, xv, 32; diseases of, 51; peoples of, 37; separate origin theory, 70 Bruce, James, xvi, 123 Bruce Telescope, ii, 136, 302 Brush Discharge, vii, 10-11, 363 Brushes, dynamo, vi, 178, vii, 363 Brussels Sprouts, xiii, 197, 222; mutant nature, 333-4 Buansuah, xii, 345 Bubonic Plague, x, 163-7; native immunity to, xiv, 357; Paré and, x, 153; prevention of, 171; spread by lice, 311 Buckwheat, xiii, 56; family, 194; flower, 46; food, viii, 364; life of, xiii, 53 Budapest, deep drilling, iii, 120-1 Buddhism, development of, xv, 199; Nirvana of, 334 Buds, never on roots, xiii, 22, 23, 29; of perennials, 53 Buenos Aires, harbor of, xiv, 270 Buffalo, N. Y., electric power system, vi, 377-8 Buffalo Bugs, xii, 123 Buffalo Dance, xv, 305-6 Buffaloes, xii, 328-9; of Great Plains, xiv, 383 Buffalo Grass, xiii, 374 Buffalo Hot Springs, xiv, 145 Buffon, founder of modern natural history, xvi, 128; lightning experiments, vi, 15; "Natural History," xvi, 116; on evolution of species, 139-40, 148 Bugles, sounding of, iv, 231 Bugs, xii, 110-14; jaws and maxillæ in, 100 Buildings, development of, xv, 266-72; dryness of air in American, i, 322, 323; earthquake construction, xiv, 342, 343; electric wiring, vii, 55-65; weathering effects, iii, 22, 24 Building Stones, iii, 370-2 Bulgaria, long life of peasants, xiii, 172 Bull Durham Sign, Broadway, vii, 341 Bullets, form and flight, v, 362, 365 Bullfrogs, xii, 180-1 Bumps, in aeronautics, i, 293, 298, 368 Bunch Grass, xiv, 380 Bunsen, carbon arc, xvi, 189; chemical work, 163; solution of spectrum lines, ii, 112 Bunsen Burner, viii, 60-1 Buoyancy, law of, iv, 103-4, 105; of air, 107, 108 Burbank, Luther, xvi, 167 Burdock, seed dispersal, xiii, 58 Burette, viii, 294, 295 (fig.) Burma, elephant of, xii, 302; rivers of, xiv, 195-6; viper of, xii, 230 Burning Oils, viii, 209 Burns, of body tissues, x, 252; from X-rays, vii, 250, x, 254 Burrels, xii, 326 Burs, chestnut and beech, xiii, 193; seed dispersal by, 343 Bus Bars, vi, 358-9 Bushland, xiv, 378-9, 380, 381 Bushmen (African), xv, 133-5; art of, 119 (fig.), 120-1, 298-300; civilization at collection stage, 196; hair of, 38; height of, 39; ostrich-hunting of, 212, 222; use of baboons, in water searching, xii, 380 Bushmen (Australian), iii, 304 Bushnell, David, v, 197 Butane, derivatives, viii, 210 Butcher's Broom Plant, xiii, 29-30 Butte Mining District, iii, 361, 368 Butter, calory value, ix, 299, x, 269, 273; composition, viii, 364; digestion of, x, 326; made by electricity, vii, 226, 227, 228; pure food, ix, 300; substitutes for, viii, 363, 364, x, 262, 267, 268; vitamines in, 259, 261, 267 Buttercup Family, xiii, 196 Buttercups, double, xiii, 51; petal arrangement, 190 Butter Fat, viii, 245, 246, 364; in milk, 363; vitamines in, 369 Butterflies, xii, 114-18; antennæ of, 101; earliest appearance, iii, 279, xii, 104; evolution of, xii, 106-7; jaws and maxillæ in, 100; number of species in N. Y., 99, origin of name, xv, 157; plant fertilization by, xiii, 123-4, 133-5, 142-3 Butterfly Orchid, xiii, 145 Buttes, made by erosion, iii, 140 Buttonball Tree, xiii, 343-4 Buttonhole Machine, invention, v, 382 Butyric Acid, viii, 220, 248 Buys Ballot's Law, i, 125, 134 Buzzards, xii, 261 Buzzards Bay, oysters of, xii, 61; tidal race at, xiv, 294 Byron, skull capacity, xv, 40 Byssus, xii, 64 Cabbage, calories in, ix, 299; in mustard family, xiii, 197; origin and antiquity, 222; sport plant, 333-4; vitamines in, x, 261, 262 Cabbage Bug, xii, 114 Cables (ocean), breaks in, xiv, 284; laying of, 283, (See also Atlantic Cables) Cables, underground, vii, 12-13, 27 Cabot, John, birth and training, xiv, 310 Cacao, xiii, 234, 235 Cachalot, xii, 298-9 Cactus, characteristics of, xiii, 378, xv, 19; leafless forms, xiii, 15; leaves of, 378, xiv, 378; prickly pear, xiii, 29 (fig.); regions of dominance, 355; stems of, 31; water-storage by, 28, 106, 379 Cactus Family, xiii, 200; restricted area, 320 Caddis Flies, xii, 106 Cadmium, symbol and atomic weight, viii, 383; test for, 287, 288 Cæsar, Julius, scientific reforms, xvi, 98 Cæsarian Section, ancient practice of, x, 14, 27 Cæsium, chemical properties, viii, 128, 132, 133, 383; spectrum, 302 Caffeine, composition, viii, 230; polyuria induced by, x, 344 Caffre, xii, 355 Caimans, xii, 198 "Cain," picture, xv, 69 Caissons (pneumatic), iv, 30-2, v, 116-21; pressure in, i, 329, iv, 129 Cake Urchins, xii, 50 Caladium, leaves of, xiii, 79 Calamus, of India, xiii, 361 Calamus Root, xiii, 188, 255 Calcite, iii, 325-6; gangue mineral, viii, 199; light polarization by, iii, 319, iv, 354 Calcium, viii, 148-9; affinities, 31-2, 101-2, 128; atomic weight and symbol, 383; compounds, 130, 138, 149-53, 195; compounds in hard water, 318, 322-4; electrolytic production, vii, 320-1; fusibility, viii, 384; in body tissues, 354; in earth's crust, iii, 308, viii, 19, 129, 192, 195, 196; in light metal group, 17, 127; plant needs of, viii, 337, 341, 344; specific gravity, 384; test for, 287, 289 Calcium Carbide, viii, 153; acetylene prepared from, 231; in nitrogen fixation, 74, i, 36; production and uses, vii, 312, xvi, 191 Calcium Carbonate, viii, 151-2; composition, 117; deposits of, 195; lime from, 149, 150; in soil sweetening, 150, 347; in water, 40, 151, 322. (See also Limestone) Calcium Chloride, viii, 152-3, 322-3; mixture with snow, iv, 175 Calcium Group, viii, 148-53; spectra, 302 Calcium Hydroxide, viii, 150, 347 Calcium Light, compared with sun's, ii, 169 Calcium Oxide, viii, 149-51. (See Lime) Calcium Pentasulphide, viii, 333 Calcium Phosphate, viii, 89, 153, 279-80, 354 Calcium Stearate, viii, 143, 323 Calcium Sulphate, viii, 117, 149, 153; in water, 40, 322-3 Calcium Sulphite, viii, 153, 372 Calcium Tungstate, color in X-rays, iv, 378 Calc Spar, iii, 325 Calculations, mathematical, development of, xv, 181-4, xvi, 61 Caldwell, Kansas, region, iii, 34 Calendar, Babylonian, xvi, 57-8; Bacon's work, 101; clothing in relation to, x, 309; Egyptian, xvi, 70; reforms of Cæsar, 98 Calibration, vii, 158, 363; of condensers, 293-4 California, aerial fish patrol, i, 48; Big Trees (see Big Trees); borax deposits, viii, 89-90; climate, xiv, 348-9, 358; climatic changes in, 361, 362; cretaceous deposits, iii, 216; crustal movements in southern, 81-2, 225; earthquakes and volcanoes, xiv, 331; forests and trees, 374; geese of, xii, 258; gold production, iii, 226, 365, 367; hot springs, xiv, 143; live oaks of, 370; lemon trees of, xv, 22; mercury production, iii, 370; ocean waves used for power, v, 174; oil fields, iii, 350; rainfall, i, 112; raisin-drying industry, v, 257; record temperature, 209; redwood forests, fog drip, 351; "road-runners" of, xii, 265; sea elephant of, 335; sea lions, 334; southern, xiv, 42; "Sunshine State," 86; tin production, iii, 368; valley of, xiv, 215 Callao, harbor of, xiv, 265 Callina of Spain, i, 96, 368 Calms of Cancer and Capricorn, i, 129, 368 Calomel, viii, 170 Caloric, iv, 47, 154, xvi, 125 Calories, definition and value, iv, 154, 312, vii, 369, viii, 361, 374, ix, 295, x, 269; electrical equivalents, vii, 382; food requirements in, ix, 296-7; in various foods, viii, 361, 366-7, ix, 299, x, 269; major, viii, 361; mechanical equivalent, ix, 295; use of, in rating food values, iv, 48 Calorimeter, viii, 360-1, x, 269 Calumet Copper Mine, heat increase in, xiv, 12 Calyx, xiii, 44, 45; absent in some plants, 46, 182; incorporated in fruits, 54 Camber, of aeroplanes, i, 288 Cambium, xiii, 24, 26, 177 (fig.) Cambrian Period, iii, 181-4, 377; animals of, 263, 267, 268, 272, 273, 277; climate, 184-5; first life in, xv, 71; fossils from, iii, 174; metamorphism of rocks in, 189 Cambridge University, founding of, xvi, 100 Cambyses, burial of army of, iii, 73 Camels, xii, 313-15; hoofs of, iii, 300; trypanosome in, x, 168 Camera, iv, 339-40, ix, 106-9; Langley on the, ii, 221; power to pierce water, i, 47 Camphor, viii, 240, 252; in celluloid, 255; smell, xi, 80; source, xiii, 255, 263 Cams, v. 39-40 Canada, animals of, xii, 287, 318, 320, 336, 348, 350, 351, 365; Atlantic ports closed by ice, xiv, 267; forests of, 371, 372; French colonization of, 191; geology, iii, 165, 167, 219, 231-2; Glacial Epoch effects, xiv, 56, 61-2, 170; Indian summer, i, 361; lakes of, xiv, 200; mining products, iii, 360, 365, 368, 376; plains of, xiv, 217; plutonic formations, 111; rainfall of, 360; tobacco production, xiii, 258 Canadian Rockies, formations in, xiv, 229; glaciers of, 55 Canals, lift locks, v, 103 Canaries Current, xiv, 304 Canary Islands, xiv, 252, 289; dragon tree of, xiii, 183-4 Cancer, cause, nature, and treatment, x, 119-20, 382, 383-4; early knowledge of, 39, 41; racial immunity and susceptibility to, xv, 48-9, 50, 51; spread and cure by surgery, ix, 255 Candle, Candlepower, iv, 351-2; compared with sun, ii, 169 Candles, blowing out of, viii, 57; burning of, in caissons, iv, 31; flame of, viii, 58, 59; materials of, 247 Candy, boiling point, viii, 299; dextrin in, 243; glucose uses, 225 Cane Sugar, xiii, 83, 214-15; chemical properties, occurrence, and use, viii, 226-7; extraction and refining, 242; fermentation, 225, 227; large molecules, 356; making of, by plant, 335; solutions, freezing point, 299; sweetness of, ix, 230; testing of, by polarized light, iv, 356 Canned foods, vitamines lacking in, x, 262, 263, 266, 267-8 Cannel Coal, iii, 344, viii, 202 Cannibalism, remarks on, ix, 280-1 Cannon, Dr., medical work, x, 295, 327; quoted, xi, 137-9 Canoes, primitive, xv, 262-4; propulsion of, iv, 33-4 Canopus, gaseous state, ii, 382; parallax and distance, 316 Canvas Buckets, use of, v, 350 Canyons, depth dependent on altitude, xiv, 159; occurrence in dry climates, 51-2 (see also particular canyons under river names) Caoutchouc, xiii, 245; chemistry and manufacture, viii, 257-8 (see Rubber) Capacity, electrical, iv, 267-8, viii, 363; in overhead transmission, 104, 105; in oscillating circuits, 286-7, 289; measurement in oscillating circuits, 294-5, 296-7; unit of, iv, 284, vii, 368 Cape Nome, Alaska, iii, 57 Capella, binary star, ii, 123; color, 297; solar star, 115 Cape of Good Hope, climate of, xiv, 358; discovery of, 309 Cape Town, oak trees at, xiv, 370 Cape Verde Islands, xiv, 252, 289; ocean deeps around, 289 Capillaries, ix, 54, 192-5; in circulatory system, x, 63, 334; oxygen diffusion through, ix, 260; passage of blood through, 210, 212, 214, 215; unknown to Galen & Harvey, x, 63 Capillarity, of soil water, viii, 37, xiii, 92-3 Capri, level changes at, iii, 81 Caproic Acid, viii, 220 Capsules, plant, xiii, 56, 69 Capuchin Monkeys, xii, 377-8 Capybaras, xii, 289 Caracels, xii, 356 Caraway Seed, xiii, 201, 265 Carbohydrate Industries, viii, 241-4 Carbohydrates, viii, 223-9, 374-5; body fuels, xi, 271, 278; daily consumption, viii, 366-7; digestion and utilization of, 356, 357, 358-9; food requirements and values, 361, 362, x, 268, 269, 271; formation by plants, viii, 219, 335, 349, 350, xiii, 81; storing of, in body, x, 272; structure and hydrolysis, viii, 217-18; use of by animals and vegetables, 246, 348, 349, 350 Carbolic Acid, viii, 238, 253, 333; as antiseptic, x, 145 Carbon, viii, 18, 42-52; affinity for oxygen, 12, 102; atomic weight and symbol, 383; chemical energy, 186-7; colors due to, 258; combustion of, 12-13, 308, ix, 26, 190; diamonds and graphite pure, iii, 328, 331, viii, 42, 43; electrical conductivity, iv, 283; electric positiveness, vi, 59, 61; ignition of, viii, 53; in body, elimination, 353; loss in fatigue, xi, 271; in hydrocarbons, viii, 205-7, 233, 234; in iron, v, 316-17, 319, 320-1, viii, 157, 158; in iron preparation, 157; in neutral refractories, vii, 307; in organic matter, viii, 42, 64, 204, 336-7; in proteins, 351; in steel, 159, 160; luminosity of flame due to, 59-60; melting point, iv, 162; necessity of, to life, ii, 242-3; percentages in coal series, iii, 345; plant uses of, viii, 49, 340-1, xiii, 14, 80, xiv, 64-5; potential energy in, iv, 82; production of pure, xvi, 190 Carbonaceous Matter, in soils, viii, 340 Carbonaceous Strata, iii, 249-50 Carbonated Beverages, viii, 43, 50 Carbonated Waters, natural, xiv, 142, 146 Carbonate Group, viii, 93 Carbonate of Lime, ancient layers of, iii, 250, 251; animal shells and skeletons of, 259, 266, 267, 268, 270; hard water due to, 126; limestone composed of, 25, 308; in sandstone, 27 (see also Calcite, Calcium Carbonate, Limestone) Carbonates, formation of, viii, 49; in blood, x, 280; metal compounds, viii, 130, 147, 198; metal extraction from, 131, 271; test of, 290 Carbon Compounds, viii, 42, 48-52, 61; optical activity, xvi, 164 Carbon Cycle, viii, 49-50, 325-6, 334-5, 349-50 Carbon Dioxide, viii, 42, 48-50; atmospheric, i, 10, 11, 13-14, 25, 322, viii, 48, 49, 67-8, 152, ix, 26, 254; body production and elimination, ix, 190, 248, 253-4, 262-7, 268, x, 270, 280, 281, 338, 339; boiling and freezing points, iv, 173; critical temperature and pressure, 172, 173; fatigue product, xi, 270-2; in blood, ix, 263, 264-7, x, 331, 339; in blood, loss in mountain sickness, i, 328; in Carbon cycle, viii, 334, 350; in limestone, 42, 49, 152; in minerals, 201; in water, 40, 111; leavening agent, 50, 136, 137; plant uses of, 219, 335, 347, 349, ix, 26-7, xiii, 80-1, 82, xiv, 65; product of combustion and decay, viii, 12-13, 26, 45, 61, ix, 26, 190; produced by fermentation, 248; production, commercial, viii, 48, 276; rock disintegration by, 194-5; thrown off by lungs, 353; vitiation of air by, 331, 332, ix, 268, x, 238 (see also Carbonic Acid) Carbon Disulphide, combustion of, viii, 61; light refraction by, iv, 331; refrigeration by, 174 Carbonic Acid, viii, 48-9, 101, 115; atmospheric content affected by light, x, 253; chemical action on rocks, iii, 24, 25, 27, viii, 194; critical temperature and pressure, iv, 172; early studies, xvi, 119-20; elimination in sleep, xi, 283; formation in body, x, 280; heat absorption by, iii, 248; in ground waters, xiv, 142, 146; in sea water, iii, 54; in sodium compounds, viii, 134-6; in urea, 230, x, 279, viii, 61; light refraction by, iv, 331; refrigeration by, 174 Carboniferous Period, iii, 197; animals of, xv, 71; landscape of, xiii, 320; length and antiquity, 314, 322; plants of, 307-11, 315-17 Carbon Monoxide, viii, 50-1, 157 Carbon Tetrachloride, vi, 101, viii, 212 Carborundum, chemical composition, 90; discovery, manufacture, and uses, vii, 300, 301, 309-11, xvi, 190; refractory, vii, 308, 311; in wireless detectors, 269 Carboxyl Group, viii, 220, 375 Carbuncles, cause of, x, 195, 311 Carburetors, vii, 124-8; mixtures in, v, 156 Caribbean Sea, hurricane reports, i, 282, 309 Caribe (fish), xii, 159-60 Caribou, xii, 320; horns of, 316 Carlsbad, Bohemia, xiv, 145, 152 Carlyle, dyspepsia of, xi, 369; on work, 276; on shame and clothing, x, 306 "Carnegie," magnetic survey ship, i, 193, vi, 39 Carnelian, iii, 337 Carnivorous Animals, xii, 332-65 (see also Flesh-eating Animals) Carnot, mathematician, xvi, 125; on heat, 135 Carolina Parakeet, xii, 266 Carolina Poplar, as index plant, i, 255 Carps, xii, 161 Carrel, antiseptic methods, x, 146, 181-3, 382 Carrel-Dakin Solutions, x, 181-3, 382 Carrion Crow, xii, 260 Carroll, Dr. James, x, 160, 161, 200 Carrots, flowers of, xiii, 49; origin, 222; swelled roots, 19; taproot of, 17 (fig.); vitamines in, x, 262, 266, 268; wild, xiii, 353-4 Carthage, and Rome, xiv, 307; destruction of fleet before, xv, 232 Carthaginians, elephants of, xii, 302; in Iberian group, xvi, 49 Cartilage, ix, 57-8; making of, 54; rib connections made of, 71; skeletons of, xii, 142 Cartridges, explosion of, v, 157; hydraulic, 100; lampblack, i, 33; modern, v, 362, viii, 145, xv, 218 Cartright, power loom, v, 376-7, xv, 246 Cascade Mountains, cirques of, iii, 66; Columbia river canyon, 39, xiv, 165-6; former volcanic activity, iii, 226; geology of, 106, 139, 213-14, 226, 227; glaciers of, 60; lakes, 143; precipitation on opposite sides of, xiv, 355; snowfall, i, 119; volcanic cones of, xiv, 100-1, 225, 315 Casein of Milk, food value, x, 259, 278 Caspian Sea, area and depth, iii, 154, xiv, 204; commercial importance, 212; formation of basin, iii, 154, xiv, 203, 205; monsoons, i, 131; salinity, iii, 154-5, viii, 139, xiv, 206-7 Cassini, Domenico, astronomical work, ii, 13, 59, 85, 133, 227-8; telescopes, 59, 99 Cassiopeia distortion from sun's motion, ii, 306; new star in, 331 Cassiterite, iii, 326, 369 Cassowaries, xii, 243, 249 Castillo, Grotto of, xv, 100 (fig.); picture from, 112 Castings, of different metals, iv, 150 Cast Iron, v, 316, 319, 320-2, viii, 157, 158 Catalan Forge, v, 315; air compression for, 89 Catalpa Trees, xiii, 271-2 Catalyzers, viii, 102-3, 375; discovery, xvi, 165; effect on speed of reactions, viii, 310, 311; enzymes as, 103, 357; various applications, i, 36-7, viii, 81, 82, 86, 174, xvi, 165 Cataphoretic Medication, vii, 247-8 Cataract, of eyes, ix, 112, 116, x, 41; ancient operations for, 27 Catarrh, germ of, x, 221 Catastrophism, xvi, 149 Cat Briers, xiii, 188 Caterpillars, xii, 115-16, 117 (fig.), 118, 119; "rains" of, i, 356-7 Caterpillar Tractors, v, 216-18, 383 Catapults, xv, 219 Cat Family, xii, 354-65 Catfishes, xii, 161-2 Cathode, defined, iv, 317, 382, vii, 251, 363 Cathode Rays, iv, 317-18, x, 184; discovery and nature, xvi, 193; fluorescence from, iv, 380 Cathode Stream, vii, 252 Cation, defined, iv, 382 Catkin-bearing Trees, fertilization of, xiii, 148 Catkins, xiii, 190, 192, 193-4 Catnip, flowers of, xiii, 205 Cats, xii, 354-56; body heat, conservation of, ix, 307; embryological resemblance to dog, xv, 54; hair erection in, ix, 161, 164; instincts of, xi, 48 Catskill Aqueduct, v, 262, 263-5 Catskill Formation, iii, 195 Catskill Mountains, formation, iii, 139, xiv, 179, 225; New York water supply from, xiv, 140; section of, iii, 138 (fig.); stream piracy in, xiv, 179-80 Cat-tails, xiii, 59, 181, 187 Cattle, domestic, origin of, xii, 330; elastic cord in neck, ix, 59; hornless, breeding of, 327; salt consumed by, viii, 140; surra disease of, x, 168; tetanus germ in, 298-9; tick diseases of, xii, 98; ungulates, 300; young of, ix, 346 Cattle Family, xii, 324-31 Cattle-raising, on grasslands, xiv, 383-4 Cattle-Raising Stage, xv, 187, 196-9 Caucasus Mountains, iii, 236; Ice Age in, 240; recent formations, xiv, 235 Cauliflower, a modified bud, xiii, 41; in mustard family, 197; origin, 222; sport plant, 333-4 Caustics, x, 255 Caustic Soda, viii, 278 Cauterization, batteries used, vii, 242; former use of, x, 38, 55, 56 Cavalieri, Bonaventura, xvi, 104, 119 Cave Bear, xiv, 149; cave pictures of, xv, 110 (fig.); relics of, 79, 82, 100 (fig.) Cave Fishes, eyes of, xii, 138 Cave Lions, xii, 359 Cave Men, xv, 76-84, 88-102; art of, 148-9, xv, 110-20, 298, 299, 300; clothing of, 257; life of, 188-91; tools and weapons, 102-10 Cavendish, Henry, chemical work, xvi, 120, 121, 177; electrical work, vi, 16, 17, xvi, 121; experiment to prove gravitation, iv, 98; hydrogen discovery, results, x, 89 Cavendish Experiment, ii, 68 Caves, Caverns, formation in limestone, iii, 127, viii, 151, xiv, 147-8; importance in history of man, 148-9, xv, 266; primitive life in, 80-1, 82-3; wind-eroded, iii, 73 Caviar, acquired taste for, xi, 72; sources of, xii, 151, 152 Cavies, xii, 289 Cavitation, v, 235-6 Cayuga, Lake, xiv, 203 Cazorla, Spain, hailstorm, i, 119 Ceiling, of aeroplanes, i, 303 Celebes, xiv, 274; animals of, xii, 310, 330, 379 Celery, blanching of, xiii, 76; calories in, ix, 299; family, xiii, 200-1; origin and antiquity, 222 Celestial Equator, ii, 70 Cell Metabolism, ix, 37-40; oxygen requirements, 182, 199, 253, 254, 260; part of cell engaged in, 42-3; sugar and fat supplies, 289; supply system, 49-52 (see also Metabolism, Basic Metabolism, Functional Metabolism) Cells (electric) see Electric Cells Cells (organic), basis of life, ix, 12, x, 119, xii, 10, 14, 25, xiii, 74, xv, 16, xvi, 142; dynamics of, xvi, 144-5; growth by division of, ix, 43-8, xiii, 166-7; living and nonliving, ix, 12-17; maintenance and growth, 34-6; metabolism of (see Cell Metabolism); motions of, ix, 73-4; of plants, viii, 337, 338, 352, ix, 26; reproduction from, 43, 324-5, 332-3, x, 228, 232, xiii, 166-7, xv, 54, xvi, 155-6, 157-8; size of, ix, 49; substance of, (protoplasm), 13 (see also Body Cell) Celluloid, composition of, viii, 255 Cellulose, viii, 223, 227-8, 229, 254-6, ix, 30; as food, 30; industrial uses, viii, 229, 241, 254-6, 261; in plants, iii, 344, viii, 49, 223, 335, 348, 349, ix, 30; in wood composition, iii, 345, viii, 44, xiv, 65 Celsius, thermometer of, iv, 136 Celsus, A. Cornelius, x, 27, 43; on sleeping sickness in Rome, 301; rediscovery of "De Re Medicina," 44 Celtic Languages, xv, 162 Celts, of Ireland, xvi, 49 Cement, chemistry of, viii, 280; manufacture, iii, 373-4 Cement Floors, in factories, xi, 361-2 Cement Gun, v, 136 Cementite, viii, 160, 273 Cement Plants, potash from dust, viii, 279; smoke precipitation, vii, 347-8 Cenozoic Era, iii, 20, 377; animals of, 284, 293, 295, 298-301; birds developed in, 297; divisions and surviving species, xv, 71; in North America, iii, 221-48; plants in, 256, 257-8 Centaurus, "coal sack," ii, 352; star cluster, 336-7 Center of Gravity, iv, 99-101; tendency of wheels to turn on, v, 150 Centers of Action, i, 218, 241-2, 368; Iceland area, 361 Centigrade Thermometer, i, 73, iv, 136, 137, viii, 27; comparison with other scales, iv, 137, 141, viii, 27, 384 Centimeter-gram-second System, iv, 46 (see Metric System) Centipedes, xii, 87-8 Central America, animals of, xii, 198, 208, 276, 289, 349; coasts, coral reefs on, 40; rainfall and rivers, xiv, 135, 195; volcanoes of, 315, 316, 325-6, 338 Central Asia, antelopes of, xii, 327; climatic changes, results of, iii, 75, xiv, 361, 362; cradle of human race, xvi, 46; desert basins, xiv, 215, 217, 355; flowers of, xiii, 202; horses of, xii, 306-7; manual of, 356; marriage custom of, xv, 282; migrations from, xiv, 362; oases of, 150-1; plains of, 215; rock weathering in deserts, 79; rodents of, xii, 294; salt lakes of, xiv, 199 Central Nervous System, ix, 129-32; at birth, 348-9; connections with glands and smooth muscles, 159-60, 162-3; in the chordata, xii, 128; preferred pathways of, ix, 134 Central Park Obelisk, iii, 23, xiv, 78-9 Central Sun Hypothesis, ii, 305 Centrifugal Force, iv, 71-5; of earth's rotation, ii, 69, iv, 74-5, 101 Centrifugal Pumps, vi, 363 Centrifugal Railroads, iv, 74 Centripetal Force, iv, 72-3 Century Plants, single flowering, xiii, 43, 53; sisal from, 240-1; water-storage by, 41 Cephalopods, iii, 20, 260, 273-6, xii, 58, 74-80 Ceraunographs, i, 163, 368 Cereal Dusts, i, 63 Cereals, best grown in grasslands, xiii, 373; evolution, iii, 257; food value, viii, 364; fruits for seed dispersal, xiii, 56, 182; phosphate requirements, xiv, 67; vitamines in, x, 260, 262 Cerebellum, ix, 144 (fig.), 145, 146 (fig.), xi, 28, 31; locomotion control through, ix, 156, 158, 167 Cerebrospinal Fluid, xi, 29 Cerebrospinal Meningitis, antiserum treatment, x, 218; germ of, 216 Cerebrum, ix, 144, 145-7, xi, 28, 29, 31-2; at birth, ix, 351; auditory area, xi, 108; locomotion action of, ix, 157, 158; seat of thought processes, 167; visual area, xi, 86 Ceres (planet), discovery, ii, 255 Cerium, atomic weight and symbol, viii, 383 Ceylon, animals of, xii, 201, 302, 328; chocolate production, xiii, 234; cinnamon production, 263, 264; coco palm of, xv, 125; leeches of, xii, 56; pearl fisheries of, 62; polyandry in, xv, 286; quinine production, xiii, 251; tea cultivation, 228, 224 (illus.) Chagres River, xiv, 195 Chahas, xii, 256-7 Chain Pump, iv, 26 Chain Reflex, xi, 39; in habit formation, 250-1 Chain Structure, viii, 233, 375 Chalcedony, iii, 337 Chalcocite, iii, 326, 360, 361 Chalcopyrite, iii, 326, 360, 361 Chaldean Eclipse Cycle (see Saros) Chaldeans, astronomy of, ii, 9, xvi, 57, 58 Chalk, iii, 377; deposits of, 216-18, 266 "Challenger," voyages of, xiv, 283, xvi, 142 Chambered Nautilus, iii, 273-5, xii, 76, 77 (fig.) Chamberlens, obstetricians, x, 79-80 Chameleons, xii, 204, 207-8, 208-10 Chamois, xii, 325 Champlain, Lake, formation, iii, 155 Champlain Sea, iii, 150, 151 Change, Albanian story of, v, 251; attention attracted by, xi, 229, 344; Cardinal Newman on, xiii, 325-6; Heraclitus on, xvi, 79; in earth's features, xiv, 28-30; need of outside influence, viii, 113; physical and chemical, 14-15 Channels, aerial mapping, i, 47; dredging of, v, 257-8 Chaparral, xiv, 379 Characters, Characteristics, inheritance laws, ix, 333-8, x, 230-2, 233-4, xiii, 332, xvi, 154, 156, 157-8; inherited and environmental, x, 228-9; racial, xv, 36-52 (see also Acquired Characters, Heredity) Charades, xv, 169 Charcoal, viii, 44; combustion of, 12-13; glow of burning, 57; heat from, 186; heat resistance, vii, 308; in gas masks, viii, 47-8, 263, 264; in gunpowder, 145 Charcot, Jean Martin, x, 360, xvi, 184 Charges, Charged Bodies (Electricity), iv, 256-67, vi, 284-302, vii, 363; chemical production of, iv, 271-2; discharge of, 262, 264-5, 267, 269, vii, 209, 366; discovery of laws, xvi, 121; electrical condition, i, 142; electricity on surface, iv, 282; induced, 260, vii, 370; leakage, 371; measurements and units, iv, 260-1 (see also Electrification, Ionization) Charlemagne, clock of, v, 62; Vikings and, xiv, 261 Charles II, founder of Greenwich Observatory, ii, 83, xvi, 124 Charles's Law, iv, 140, viii, 107-8 Charleston (S. C.) Earthquake, iii, 95, 97-8 Charleston (W. Va.) region, iii, 34 Charts, marine, i, 271-6; meteorological, 206-8; phenological, 254; synchronous and synoptic, 214-15 Chautauqua, Lake, origin, iii, 145-6 Chaucer, "Doctor" of, x, 41; language of, xv, 156 Chauliac, Guy de, x, 39, 40-1 Checkered Adder, xii, 222 Cheese, calories in, ix, 299; composition and value, viii, 363; manufacture of, xiii, 71 Cheeta, xii, 365 Chellean Implements, xv, 105, 106-7 Chemical Affinity, viii, 12; electrical nature, xvi, 122; electromotive series, viii, 127-9; intensity measured by heat, 308, 360; of metals for nonmetals, 20; source of energy, 267, 268 Chemical Changes, nature of, viii, 9-15, 188; signs of, 100-1 Chemical Compounds (see Compounds) Chemical Elements (see Elements) Chemical Energy, viii, 12, 186-7, 267, 268; electricity from, 167-8 Chemical Equations, viii, 13, 94-6, 376 Chemical Industries, viii, 241-84 Chemical Reactions, viii, 99-105; defined, 381; equations of, 94-6; equilibrium, 103-5, 190-1; heat of, 308; reversibility, 21, 101; of solutions, 36, 37, 119-25, 311; speed of, 310-11; types, 20-1 Chemical Warfare, viii, 262-4, x, 186-8 Chemical Warfare Service, x, 187-8; device, viii, 233 CHEMISTRY, Volume viii Chemistry, beginnings of modern, viii, 34; concrete science, xvi, 42; daily interest of, 13-15; defined, viii, 11, xvi, 36; difficulties of study, viii, 10-11; exact, positive science, x, 368; former realm, xvi, 14; historical development, 54, 59, 73-4, 109, 110, 112, 115, 119-21, 133-4, 159-65; medicine and, x, 81, 369; nomenclature, viii, 97-8; subjects dealt with in, iv, 12; ultimate identity of organic and inorganic, x, 69 Chemosynthetic Organisms, xii, 15 Chemotaxis, xi, 50-1, 59, 61 Chemotherapy, x, 381 Cherbourg, breakwater at, xiv, 301; wave power at, 300 Cherrapunji, Assam, rainfall at, i, 111-12 Cherries, drupes, xiii, 54; origin and remarks, 224-5 Cherry Trees, xiii, 271-2; lenticels on, 26 Chert, formation of, iii, 13 Chesapeake Bay, aerial fish patrol, i, 48; drowned valley formation, xiv, 40, 255-6; ducks of, xii, 257; oysters of, 61; ria coast, xiv, 257; wave erosion in, iii, 56 Cheselden, William, x, 92, 123 Chest, diseases, studies of, x, 110, 112; examination methods, 98-9, 108-9, 371, 373; fixation of, 304-5 Chestnut Trees, family of, xiii, 193; in American forests, xiv, 373 Chevrotains, xii, 313 Chewing, act of, ix, 82; importance of, 227-8, 229, 230 Cheyne-Stokes Respiration, x, 340 Chiasmodus, xii, 24 Chicago, growth due to railways, xiv, 219; level changes at, iii, 82; sewage of, viii, 326; terminals, electrification, vi, 162; underground trolleys, vii, 12; ventilation standards, viii, 332 Chicago Fire, dust from, i, 56 Chicago, Lake, iii, 148, 149 Chickadees, xii, 268 Chicken Cholera, inoculation for, x, 141-2, 208 Chicken Pox, immunity to, x, 207 Childbirth, among savages, xv, 278 Child Labor, factory system and, x, 244; laws, remarks on, vii, 33 Children, adenoids in, ix, 224, x, 341-2; artistic impulse in, xv, 296; basal metabolism in, x, 271; bones of, ix, 56, 57; care in development of, 352; care of, by state, xv, 290-1; choice importance to, xi, 266-7; clothes for, x, 308; cold baths for young, 312; convulsions in, ix, 133-4; cretinism in, x, 349-50; darkness effects on, 253; dreams of, xi, 293; ear troubles in, ix, 104; education and environment importance, 344, 352; exhaustion in, xi, 273; foods for, ix, 33-4, 242, 295, x, 314-15; grasping reflex, importance, xi, 43; growth period, ix, 47-8; habit acquisition, xi, 247, 249; habit of evacuation in, ix, 252; heart rate in, x, 334; house-breaking, xi, 251-2; imitation in, xv, 66-7; language of, 142-3, 153; malnutrition causes, ix, 228; objection to sour tastes, 95; relationships under polyandry, xv, 286, 294; resemblance to parents (see Heredity); savage attitude towards, 135, 195, 198; skull growth in, 40; soaps desirable for, x, 311; suggestibility, xi, 307; teeth, care of, ix, 228, x, 312-16; transmission of nonhereditary characters to, ix, 343-4; walking of, on what dependent, 351 Chile, Bolivia and, xiv, 306; climate of, 358, 371; coasts, 258, 265; deserts of northern, xiii, 377; nitrate fields, i, 34, 35, viii, 64, 72, 197, 280, xiv, 66; temperate forests, xiii, 372 Chilled Iron, v, 241 Chilling, of body, x, 252-3, 306, 311; effects, ix, 323 Chimborazo, Mount, formation, xiv, 225; observatory site, ii, 149-50 Chimpanzees, xii, 383-4; brain of, xv, 62 (fig.), 96; expression of passion by, 65; hand and foot in, 58-60; mandible of, 94; reasoning power in, 67-8; skeleton compared to man's, 59 China, agriculture in north and south, xiv, 72-3; ancient civilization, x, 13, xv, 123, 127; beriberi in, ix, 35; bubonic plague in, x, 165; Cambrian deposits, iii, 184; coal, in, 345; coasts, xiv, 248, 251, 257; corn growing, xiii, 212; David's deer, xii, 316; dust whirls, i, 60; famines, xiv, 73; fault-blocks of north, 125; fishing with cormorants, xv, 223-4; ginkgo tree, xiii, 315; goral of, xii, 325; gunpowder invention, v, 361; hookworm in, x, 174; influence on West, xiv, 357; Jesuit survey, xvi, 123; loess formations, i, 53-4, iii, 74, xiv, 63, 72-5; medical education and Rockefeller Fund, x, 172; medicine of ancient, 13; meteorological service, i, 223; mountain valley conditions, xv, 131; opium and, xiii, 253; plains and mountains, xiv, 217; population distribution, 219; rice-growing, xiii, 213, 214; rivers of, xiv, 196; shark's fins as food in, xii, 147; smallpox inoculation in, x, 100, 207; storm signals, i, 283; sugar in, xiii, 215; tea in, 227, 228; temple orientation, ii, 26; trees of, xiv, 377; wheat in, xiii, 210 (see also Chinese) China (pottery), viii, 283 China Clay, iii, 333 Chinch Bug, xii, 114 Chinchillas, xii, 289 Chinese, ancestor worship of, xv, 341; ancient agriculture, xiii, 210; ancient civilization, x, 13, xvi, 53, 54, 62; ancient knowledge of cloves, xiii, 262; ancient knowledge of lodestone, iv, 52, vi, 28; calculating machines, xv, 183, xvi, 61; finger nails of, xv, 260; ideas of future life, 336; ideas of eclipses, ii, 209; in tropics, xiv, 356; opium use, xiii, 253; paper invention, v, 290; prepotency in crosses, x, 230; printing invention, v, 300-1, xv, 179; use of feet by, 61; veneration for writing among, 164; well-water boiling, xiv, 140; women, feet of, xv, 254-5, 260, 261 (fig.); women, hairdressing of, 261 Chinese Astronomy, ii, 21-2, 331, xvi, 56-7 Chinese Language, xv, 170-1 Chinese Writing, xv, 169-72 Chinooks, i, 133, 369 Chipmunks, xii, 293-4 Chitin, xii, 39, 69 Chitons, xii, 58, 67 Chloramin, x, 181, 183 Chloramine T., x, 382 Chloride of Lime, viii, 333 Chlorides, halogen derivatives, viii, 210; metal occurrence in, 130, 198 Chlorine, viii, 18, 22, 84-5, 181, 297-8; as antiseptic, 333; atomic weight and symbol, 383; bleaching by, vii, 354, viii, 86, 146, 256, 274; gold reaction with, 174; in body tissues, 354; in silicates, viii, 193; manufacture and uses, 274, 284; molecular speed, 24; obtained from salt, 138, 140, 275; plant uses, 337, 341; solubility, in water, 111; tests, for, 286, 287, 290; use in chemical warfare, 262-3, x, 186; water disinfection by, viii, 86, 274, 319, 321 Chlorine Derivatives, viii, 210, 211-12, 231 Chlorite, iii, 326-7 Chloroform, viii, 52, 212; as anesthetic, x, 125 Chlorophyll, ix, 26, 27, xii, 11-12, 14, xiii, 79-80, 81, 84; absent in saprophytes, 99, 100; action in plants, viii, 335 Chocolate, calories in, ix, 299; history and production, xiii, 233-5 Choice, power and importance, xi, 260-3, 265-7; power of, in muscular responses, ix, 95, 121, 140 Choke Coils, vii, 17, 50 Cholera, discovery of germ of, x, 149, xvi, 184; former ideas of, x, 286; from water pollution, viii, 318; germ of, x, 195; immunity to, 207; inoculation against, 208; racial susceptibility to, xv, 50, 51 Choleric Temperament, xi, 153 Cholesterin, ix, 275 Chordates, xii, 127-9; coelom in, 27 Chords, major and minor, xi, 106-8 Chorea, epidemic of, in Europe, x, 60; rheumatism and, 224; Sydenham on, 74 Christianity, Locke's "rational," xvi, 115; Roman and medieval development, 99-100 Christian Science, attitude toward pain, xi, 116; source of power, 306 Christmas Trees, electric lighting, vii, 342 Chromatic Aberration, ii, 99-100 Chromatin, ix, 41, 42, 44-7, 328 Chrome Yellow, viii, 162 Chromium, viii, 154; affinity strength, 128; alloys of, 273; atomic weight and symbol, 383; extraction from ores, 271; specific gravity, 384; test for, 287, 288-9; use and occurrence, xiv, 238 Chromophor Group, viii, 258, 259 Chromosomes, ix, 46; arrangement in pairs, 329, 330; heredity controlled by, 328-41, x, 232-3; human varieties, 233; likeness in all cells, ix, 329; number of, 46, 329, 339; origin of energies, xvi, 145; sex, ix, 339, x, 234, xvi, 156; splitting of, in cell division, ix, 45 (fig.), 46-7, 332, 333 Chronic Diseases, wasting process of, x, 214 Chronometers, v, 65-7; regulation to temperature changes, iv, 148 Chrysolite, iii, 334 Church, Prof. J. E., i, 118 Chyme, x, 325, 326 Cicadas, xii, 112 Cider, making of, viii, 249; turning to vinegar, 218 Cigarette-smoking, dust particles from, i, 62 Cilia, of bronchial tubes, x, 202; of simple animals, ix, 73-4 Cinchona, use of, in medicine, x, 154-5, xvi, 109 Cinchona Plantations, xiii, 251-2 Cincinnati, early growth, xiv, 219; water supplies, viii, 318, 322 Cinder Cone, eruption, iii, 226 Cinder Cones, xiv, 100, 102 Cinematograph, in astronomy, i, 162, ii, 212 Cinnabar, iii, 327, 370 Cinnamon, xiii. 263-5 Circles, appearance of circumscribed, xi, 186; divisions invented by Ptolemy, xvi, 94; regarded as perfect curves, ii, 34, 49 Circuit Breakers, vi, 101-3, vii, 36, 37-48 Circuits, Electrical, kinds defined, vii, 364; overloading of, vi, 9, 72; primary and secondary, 9, 308; proportioning of partial, iv, 300-1; protection against overloaded, vii, 34-50 Circular Mils, iv, 282-3, 382 Circular Reflex, xi, 42; in habit formation, 252-3 Circulation of Blood, ix, 195-200, 51 (diagram), x, 331, 337; discovery, ix, 192, x, 61, 63-6, 69, xvi, 106-7; discovery prepared by Vesalius, x, 51, 52; efficiency, climatic effects on, x, 238-9; former ideas of, 62-3, 65-6 Circumcision, among early Jews, x, 15; untransmitted, 230 Circumzenithal Arc, i, 178, 180, 181, 369 Circues, iii, 66, xiv, 58 Cirro-Cumulus Clouds, i, 100, 103, 298 Cirro-Stratus Clouds, i, 99-100, 103, 179 Cirrus Clouds, i, 97, 99, 103, 179; false, 102, 104, 372 Cirrus Haze, i, 100 Cities, aeroplanes to relieve congestion, i, 41-2; climate, 333; dependence on farms, vii, 221; importance of lighting, vi, 279-80; sewage disposal, viii, 324-9; sites, favorable to, xiv, 219; snow removal, i, 117, xiv, 140-1; transportation facilities, vii, 198; water supplies and purification, viii, 317-24; white ways of, vii, 339-41 Citric Acid, viii, 222, 223; formed by plants, 336; solubility, 112 Citrus fruits, acids of, viii, 223 Civet (oil), xii, 353 Civets, xii, 351, 352-3, 354 Civilization, American, xv, 12, 131-2, 203; arts and sciences in, iv, 9, 10; climate and, xiv, 344, 357-62, xv, 31, 123-7, 383, xvi, 141; clothing, shelter, and fire in, ix, 308-9, xv, 229; conditions necessary to, 127-32; development of, 3-4, 13-14, 28-31, 187-204; dominant human impulses in, 185, 383; earliest seats, xvi, 47; evolution in, xv, 382, 383-4; foresight and, 383; geographic factors, xiv, 10, 31, xv, 122-3, 128-39; government and, 380; historic and prehistoric periods, xv, 167, 322; influence of environment on, 122-39; labor and, 125-6; measured by timepieces, v, 57; medicine and, x, 31; moral laws and, xvi, 45, 47-8; natural laws and, xv, 47-8, 382-3; specialization in, 131-2, 203; stages of, 187-204; struggle to establish high associations, xi, 204; transportation and, v, 18; various machines and, 300 (see also Progress) Civilized Races, facial angle in, xv, 45; feet of, 60-1; jaws in, 43; monogamy of, 289, 290, 295; natural selection in, 47-8 Civil War, Appalachian mountaineers in, xiv, 243; captive balloons in, v, 225; improvement of weapons in, 362, 380; medical service in, x, 180; scurvy in, 265; Selfridge's periscope, v, 200; Virginia weather, i, 308, 338; western rivers in, xiv, 194 Clams, xii, 58-60, 66-7; shells of, iii, 272 Clam Shell Cove, Staffa, xiv, 130 Clans, formation of, xv, 362-3 Clarinet, iv, 234 Clark, Alvan, telescopes, ii, 106, 109, 143 Clarksburg, W. Va., deep well at, iii, 120 Clausius, xvi, 135 Clavichord, xv, 318 Claw Hammers, v, 25 Clay, composition and properties, viii, 90, 282; composition, origin and uses, iii, 25, 372-3; elasticity of, iv, 36; imperviousness to water, xiv, 137; in soils, iii, 27-8; red, on sea bottom, 54; residue of primary rock, viii, 195; rock formed from, iii, 13 (see Shale) Clay Worm, xii, 54 Cleanliness, bathing for, ix, 313; health and, x, 311; in war against tuberculosis, 290; ventilation factor, ix, 270 Cleansing, action of soap in, viii, 141-2; chemicals used in, 135, 141, 146, 147, 208-9 Cleavage, of crystals, iii, 318, viii, 202; of various minerals, iii, 321-41 Cleistogamous Flowers, xiii, 120 Clematis, as index plant, i, 255; family of, xiii, 196 "Clermont," steamboat, v, 192, 377 Cleveland, Ohio, water supply system, v, 260-1; water supplies and typhoid rate, viii, 322 Cliffs, formed by faulting, iii, 87-8, xiv, 38; in inclined strata, xiv, 84-5, 88; loess, iii, 74; of jointed rocks, xiv, 133; sea, 251; undercut by wind, iii, 73 Climate, Climates, i, 197-211; altitude effects, xiv, 220, 223; carbon dioxide effects, viii, 49; changes of, i, 199-202, xiv, 29-30, 360-2, xv, 72, 73, 74; changes affecting drainage systems, xiv, 188; changes, artificial, i, 345; changes, extinction of races by, xv, 99; changes in relation to plant distribution, xiii, 320, 321; civilization, and, xiv, 344, 357-62, xv, 123-7, 383; classification, i, 208; data and statistics, 202-8, 214; definitions, 199; determining elements of, xiv, 344-56; earth's internal heat and, 13; effects, historical and biological, xvi, 141-2; forest and prairie types, xiii, 348-9; forest effects on, xiv, 379; Gulf Stream effects, viii, 37; hot, unhealthfulness of, x, 251; human effects of, i, 316, 323-4, 327, 331; human efficiency and, xiv, 357; of past ages, iii, 172-4, 178, 184-5, 202, 203, 204, 220, 241, 246-8, xiii, 307-8, xv, 72, 73, 74, 76; of plateaus, xiv, 222-4; plant societies determined by, xiii, 381-2; rugged, effects on circulation, x, 238-9; therapeutic value of, 383; topographical effects of, xiv, 41-2, 51-2, 124; vegetation determined by, 363-79, 380-1; zones of, (see Zones) Climatic Charts, i, 206-8, 212-13 Climatography, i, 208, 369 Climatology, in therapeutics, x, 383; present state, i, 211, 369 Climbing Plants, xiii, 27, 65; in tropical forests, xiv, 368 Climographs, i, 324, 369 Clinton Iron Deposits, iii, 358 Clione, xii, 19 Clippers, old Atlantic, v, 188 Clocks, balance wheels of, v, 68; Chaldean, xvi, 58; electric regulation, v, 74; first conceived in cathedral, 109; historical development, 58-65; Jerome's standardized, 50-1; pendulum escapement, 73-4 Closed Circuits, defined, vii, 364 Cloth, making of, v, 268-83 (see also Weaving) Clothes, Clothing, body heat regulation by, v, 348, ix, 308-9, 311-12; civilization in relation to, ix, 308-9; colds in relation to, x, 240, 253; "habit" in, xi, 247; hygiene of, x, 306-10; infants, ix, 351-2; origin and purposes of, x, 306, xv, 252-5; primitive, v, 14, xv, 256-7; touch sensations of, ix, 92; warmth dependent on air insulation, iv, 178; working, xi, 279, 362 Clothes-driers, centrifugal, iv, 73 Clotting of Blood, ix, 180, 189 Cloud Banners, i, 104-5, 369 Cloudberry, spread, xiii, 342 Cloudbursts, i, 109, 110, 111, 369, vii, 218; destruction effected by, xiv, 41 Cloud Caps, i, 104-5, 369 Cloudiness, measurement, i, 85 Clouds, i, 90-105; aviation in, 300-2; Brocken specters in, 185; earth heat retention by, iv, 183, 184; electrical discharges, vii, 18, 207-10, 213; electrification, i, 150, 151, vii, 206, 207, 217; electrification of earth by, iv, 269, 270; formation and kinds, i, 90-105; formation, cause of rapid, viii, 304; formed by forest fires, i, 333; heights, 17-18, 103-4; light diffraction by, 183, 185; noctilucent, 17-18, 58, 377; none in stratosphere, 20; observation at weather stations, 85-6; paintings of, 105; pictures, where obtainable, 103; self-luminous, 149; snow and rain without, 119; thunderstorm, vii, 217 Clouet, steel experiment, xvi, 174 Cloven-footed Animals, xii, 310 Clover, fertilization, xiii, 138; nitrogen fixation, by, viii, 74, xiv, 66; sleeping of leaves, xiii, 113 Clover Seed, method of gathering, v, 240 Cloves, Clove Trees, xiii, 262-3 Club Mosses, fixity and variation, xiii, 326, 327; history, 305-6, 307, 314, 317, 323; number of species, 323; present and former species, iii, 254, xiii, 306, 308 Clutches, automobile, vii, 143; electromagnetic, vi, 104 Cnidus, School, of, x, 22-3 Coagulation, by cooking, viii, 368; of colloids, 315; of proteins, 352 Coal, "Blue," v, 174; carbon dioxide from, amount, i, 13; conversion to electric power, vi, 216; deposits in mountains, xiv, 237; deposits in U. S., iii, 345-8; excavating by machine, v, 262; formation, iii, 198-201, 253-4, 343-5, viii, 44-5, xiii, 10, 68, 311-13; handling in power plants, v, 353-4, 357; heat measurement, viii, 360-1; heat value, iv, 193; importance, iii, 343, 345-8; kinds, 344; not a mineral, 307; Permian deposits, 204; specific gravity of, iv, 112; supply, use, and waste, iii, 346, v, 171-2, vi, 352, viii, 283; water power and, xiv, 191; "white," v, 76; work value, how estimated, iv, 189-90, 193-4 Coal Age, iii, 202; insects of 279; landscape of, 272 (Pl. 15); length and antiquity, xiii, 314; plants, iii, 253-4, xiii, 307-11, 315-16 (see also Pennsylvanian Period) Coal Dust, as engine fuel, v, 156, 212; explosions, i, 63 Coal Gas, in balloons, v, 223; liquefaction of, iv, 171 Coal Gas Engines, v, 155 Coal Mines, compressed air uses, i, 26 (see also Mines) Coal Series, iii, 344-5; carbonization in, viii, 44 Coal Tar, production and products, viii, 252-4; saving of, 47 Coal Tar Hydrocarbons, as motor fuels, viii, 209 Coastal Plains, xiv, 213-14, 215 Coast Range Mountains, geology of, iii, 89, 94-6, 130, 224, xiv, 127-8, 229 Coast Range Revolution, iii, 224 Coasts, xiv, 246-71; Atlantic and Pacific types, 247-50; compound, 254, 264; cycles of development, 254-5; economic importance, 264-5; emerged, iii, 56-7, xiv, 253, 262-3; hanging valleys on, 57-8; historical effects of, 249-50; neutral, 248, 254, 263-4; photographic mapping, i, 47-8; regular and irregular, iii, 56-7, xiv, 250-3, 255; submerged, iii, 57, xiv, 253, 255-62; wave destruction of, iii, 55-8, xiv, 44-7, 216, 301-3 Coatzacoalcos, harbor of, xiv, 266 Cobalt, viii, 154; affinity strength, 128; atomic weight and symbol, 383; classification place, 178, 183; magnetic susceptibility, iv, 251; ores, viii, 198, 270; specific gravity, 384; test for, 287, 289 Coblenz, Roman name, xiv, 89 Cobras, xii, 226-9; mongooses and, 352 Cocaine, an alkaloid, viii, 240; history and uses, xiii, 254-5; taste sensations reduced by, xi, 72 Cocci, (bacteria), x, 195 Cochineal, source, xii, 112 Cockatoos, xii, 266; Arara, v, 9-10 Cocklebur, xiii, 57 (fig.), 343 Cockroaches, xii, 107; ancient, iii, 279, xii, 104 Cocoa, xiii, 235; American origin, xiv, 382; source, 383; polyuria induced by, x, 344 Cocoa Butter, viii, 246 Coco de Mer, xiii, 60, 154 Coconino Forest, xiv, 373-4, 378 Coconut Oil, ix, 28, xv, 125 Coconut Palm, xiii, 219-20, 244, xv, 125; chatties, intoxication from, xii, 371; on coral islands, 42; fossil found in France, xiii, 319; seed dispersal by, 59, 346 Coconuts, character, uses, and production, xiii, 219-20; double, of Seychelles Islands, 60; gathering of, by monkeys, xii, 378; source and uses, xv, 125; unaffected by sea water, xii, 42 Cocoons, xii, 118 Coction, x, 21, 40 Cod (fish), xii, 163-4; eggs of, 141 Cod Liver Oil, vitamines in, x, 261 Coefficient of Expansion, iv, 145, vi, 265 Coelenterates, iii, 259, 266-7, xii, 26, 33-43 Coelom, xii, 27, 48 Coeur d'Alene Mining District, iii, 362-3, 368 Coffee, history and production, xiii, 231-3; insomnia from drinking of, ix, 219; polyuria induced by, 274-5, x, 344 Cog Wheels, v, 29; screw and, iv, 92, 93 (fig.) Coils, electromagnetic, vi, 92, 93, 98-9; form-wound, 202, 223; induction, vii, 364; primary and secondary, iv, 304, 383, vi, 308, vii, 364; resistance, 364 Coins, chemical analysis of, viii, 286, 291; copper alloys in, 164, 171; gold and silver, making of, iv, 150 Coke, discovery, v, 315-16; manufacture and use, viii, 46-7, 252 Col (meteorology), i, 238, 369 Cold, body regulation to, x, 250; clothing as protection against, 306; comparative degree of, v, 345; physiological effects of, ix, 37, 78-9, 319-20, x, 239, 252-3, 271; "production" of, v, 345-7; sensation of, ix, 93-4, 319-21, xi, 109, 112-13, 114; skin defense against, 113 Cold Air Machines, v, 352-3 Cold Baths, ix, 313, 321-2, x, 240, 253, 312, 383 Cold-Blooded Animals, ix, 305; diseases of, x, 206; heart of, ix, 84; temperature changes and, 78-9, 306-7, x, 250 Colds, air during epidemics of, viii, 332; catching of, ix, 322-3, x, 239, 252-3, 306; diseases from, 253; ears affected by, ix, 103; from uncleanliness, x, 311; head, 341; infectiousness, i, 326; susceptibility of men and women to, x, 240; taste sensations in, xi, 73 Cold Storage, iv, 187-8, viii, 371; effect on vitamines, x, 263; electrical, vii, 229-30 (see also Refrigeration) Cold Sweat, xi, 131, 132 Cold Waves, i, 370; prediction of, 239 Coleus, xiii, 42, 79, 205 Collectors, electrical, i, 144, 370 Collection Stage, xv, 187, 188-91 College Students, study habits, xi, 212, 289 Collodion, making of, viii, 255 Colloids, viii, 314-16, 375; origin of life from, xii, 11-12; relation of water to, viii, 355-6 Colonnaded Spectrum, ii, 115 Color--Colors, chemistry of, viii, 85-6, 258, 259, 312; complementary, iv, 366-7, xi, 91-4; contrast, ix, 95; determined by vibration rate, 114, 115; distance effects, xi, 182; flame, viii, 301; heat absorption by, x, 309; hue, tint, and saturation, xi, 90; illusions of, in different lights, iv, 323, 324, 370, 379-80; induction of, xi, 94-5; in interior decoration, vi, 273, 274-5; memory, xi, 220-1; mineral identification by, viii, 201-2; mixtures, iv, 369, xi, 92-3; neutralization, 91-3; of glass, viii, 282; of objects, iv, 364, xvi, 119; of pigments, iv, 369-70; perception and sensation of, 360-1, 364-5, 366, vi, 282, ix, 114-17, xi, 89-90, 91-2, 95-6; physical effects, 63, 96; primary, iv, 366, xi, 90; psychological effects, vi, 273, 274-5; racial classification by, xv, 32-34, 36-7; rainbow, i, 175, ix, 115; spectrum, iv, 357-9; sunrise and sunset, i, 166, 167-8; temperatures for different, iv, 361; wave lengths of, 359, 360, 365, xi, 90; white light, (see White Light) Colorado, arid topography of, xiv, 42; glaciers of, 54; Jurassic strata of, xii, 165; mining products, iii, 362, 363, 364, 366 Colorado Plateau, iii, 140, 229-30 Colorado River, navigability, xiv, 195; Salton Sink and, iii, 156-7, xiv, 205; superimposed character, 173; water supply of, 182 (see also Grand Canyon of the Colorado) Color Blindness, ix, 116, xi, 93; inheritance of, ix, 340-1, x, 234; in men and women, ix, 340-1 Colored Hearing, xi, 222 Color-Index of Stars, ii, 297-8 Color Photography, iv, 368-9 Color Printing, iv, 370-1; in newspapers, v, 304 Color Vision, iv, 364-5; inheritance of, ix, 340; limits of, iv, 360-1; theory of, x, 96 (see also Colors) Colt Gun, v, 363-4 Columbia Plateau, iii, 105, 181, 227-8, xiv, 104, 164, 170, 172, 188 Columbia River, xiv, 174-5; canyon of, iii, 39, 226, 228, xiv, 165-6; navigability, 195; salmon of, xii, 157 Columbine, fertilization, xiii, 126-8; flowers, 196 Columbium, atomic weight and symbol, viii, 383 Columbus, compass troubles of, iv, 52-3, vi, 27; debt to early scientists, ii, 12, 13, 40; discovery of America, xiv, 309; Genoese birth, 310; in Sargasso Sea, xiii, 73; on rubber balls in Haiti, 245; potatoes found by, 218, 219; syphilis introduced by sailors of, x, 60; tobacco-using seen by, xiii, 256; trade winds on voyage, i, 128-9 Columnar Structure, iii, 111, 212 Combustion, iv, 138; chemistry of, viii, 11-13, 53-63, 100; heat of, 308; oxygen and, i, 10; oxygen and, viii, 35-6, 61; power developed by, ix, 15-16 Comets, ii, 273-82; asteroids and, 258; dangers to earth, 279-80; disintegration, 286-7, 288; families related to planets, 270-1; first scientific studies, 40, 41, 57; former ideas, 83-4, 85; habitability, ii, 250-1; in relation to solar system, 164; Newton's views, 85; orbits discovered, 85; orbits and meteor streams, 287; photographic study, 134; Seneca on, 85; solar corona and, 224; various particular, 280-1, 286 (see also Halley's Comet) Commensalism, xii, 32 Commerce, ocean, development of, xiv, 305-11 Commercial Meteorology, i, 261-70 Common Salt, composition and properties, iii, 332, vi, 109-10, 111, viii, 84; deposits, iii, 332, 374-5, viii, 139-40, 196, xiv, 141; deposits from atmosphere, i, 59-60; in body fluids, ix, 174, 175; in diet, x, 256; in ground water, xiv, 142; in protoplasm, ix, 32; in sea and inland waters, iii, 51-2, 152-3, 154-5, 332, 374, viii, 138-9, 195-6, xiv, 206, 295-7; mixture with ice, temperature resulting, iv, 175; physical and chemical divisions, 21; plants and, xiv, 364; production, iii, 374, 375, viii, 140, 275; refining of, for table, xiv, 296; size of molecules, vi, 112; taste of, xi, 70, 71, 72; uses, iii, 332, viii, 138, 140, 276-7 (see also Sodium Chloride) Commutators, electrical, iv, 308, vi, 159, 177-9, 344-5; use and construction, vii, 364-5 Como, Lake, iii, 146 Comparisons, measuring by, vii, 341 (see also Contrasts) Compass, (Gyroscopic), iv, 254-5, v, 201, 340, 384 Compass (Magnetic), vii, 365; compensation on iron ships, iv, 254, v, 340, vi, 42; development, xvi, 102; deviation, defined, iv, 247, vi, 42; disturbances accompanying aurora, i, 161; electric current effects, vi, 20, 88; invention, 29; magnet effects, 27, 32, 42-3; modern improvements, 41-2; needle, pointing and declination of, iv, 246-7, (see also Magnetic Needle); sun disturbances, vi, 40; variation, defined, iv, 247; variations on voyage of Columbus, 52-3, vi, 27 (see also Mariner's Compass) Compensators, electrical, vi, 253-5 "Complete Recall," xi, 378 Complexes, mental, x, 355-6; in hysteria, 361, 362 Composing Machines (see Linotype, Monotype) Composition of Forces, iv, 75-7 Compostella, Spain, shrine at, xii, 65 Compounds, Chemical, viii, 16, 100, 375; analysis of, 285-95; colors of, 312; combustion of, 61; constancy, 110, xvi, 160; contrasted with mixtures, viii, 15; decomposition, 101-2; electrical balance, 121; formation types, 20, 100; formulæ, 91; metallic, 130, 146; molecular weights, 92; multiple proportions law, 110; nomenclature, 97-8; organic (see Organic Compounds); substitution in, 102; unstable, 66; with water, 20, 38-9 Compound-Wound Dynamos, vi, 187, 188-9, 191-2 Compound-Wound Motors, vi, 233-5 Comprehensive Terms, xi, 191 Compressed Air, applications and uses, i, 25-6, 27-9, iv, 30-2, 106, 129-31, v, 111-38; discovery, 109-11; expansion effects, cooling by, iv, 191, v, 128-9, 351-3, xiv, 14; heat of, v, 126-8, 161, 351; methods of compression, 89-93, 126-7, 174; physiological effects, i, 329, iv, 31-2, v, 119-21; pressures used, i, 27 Compressed Air Locomotives, i, 26, 27, iv, 129, v, 133 Compression, heat of, i, 90, v, 126-8, 161, 351 Compressors, Air, v, 89-93, 127, 351 Compte, on sciences, x, 368 Comstock Mines, Nevada, iii, 366, 368; temperature in, 121 Concentration, chemical, viii, 310-11; mental, xi, 235-6, 378-9 Conchs, xii, 72-3, 73-4 Concordant Coasts, xiv, 248, 249 Concrete Buildings, value in earthquakes, xiv, 343 Concrete Dams, expansion joints, v, 71 Concrete Sciences, xvi, 42 Concrete Ships, v, 194-5 Concubinage, xv, 289, 290 Condensed Milk, scurvy from, x, 266 Condensers, electrical, iv, 265-7, vi, 170-4, 301-5, vii, 365; applications, vi, 285-6; capacity of, iv, 267-8; dielectric, vii, 366 (see Dielectric); discharge methods, iv, 267, vii, 366; in automobiles, vii, 138-9; oscillating currents, 373-4; plate, vi, 170, 293-4, 295; purpose, vii, 363; synchronous, vi, 262; use in wireless communication, iv, 314, vii, 263, 264, 266, 267 Condensers, Steam, v, 145, vi, 354-6 Condiments, as foods, viii, 362, 366; effects on stomach, ix, 243-4; sources, xiii, 265 Conditioned Reflex, xi, 198-201, 204; in advertising, 348; in habit formation, 251-2; in hypnotism, 321-2 Condors, xii, 260 Conduct, rules of, how enforced, xv, 374-5 Conduction, of heat, iv, 138, 177, 178-9 Conductors (electrical), iv, 259, vi, 77, 294; acids and bases as, viii, 122, 123; air, i, 144-5; copper, viii, 164; discovery, vi, 13; for radio currents, vii, 296; resistance of, iv, 281-2 (see Resistance); tabular information, vii, 377-84; temperature effects on, iv, 301; various materials as, 283 Conductors, (heat), iv, 176, 177, 179 Conduit Wiring Systems, vii, 55-60, 365 Condyle, xii, 239 Confectionery, poppy seed used in, xiii, 250, 254; pure food law on, viii, 370-1 Confidence, psychological effects, xi, 212-13 Conglomerate, iii, 13, 377; sedimentary rock, xiv, 18 Congo River, connections with Nile sources, xiv, 186-7; furrow of, 287; ocean slope at mouth of, 24; varied course, 155 Congo River Basin, hippopotamus of, xii, 310; okapi of, 321 Congo Tribes, habits of, xv, 225, 370 Conies, xii, 288, 304 Conifers, xiii, 174, 178; American forests of, xiv, 371, 372, 374; ancestors of modern, xiii, 310; first appearance, iii, 256; number of species, xiii, 323; transitional form, 318 (see also Gymnosperms) Conjugated Proteins, viii, 352 Connecticut, drainage studies, xiv, 131; oyster industry, xii, 61 Connecticut River, course, iii, 234; preglacial valley, xiv, 60 Connecticut Valley, down warping of, iii, 210; igneous rock formations, xiv, 107, 111; lava deposits, iii, 212; origin, 232; rocks under, 213 (fig.); tracks of extinct animals in, 16, 291; volcanic action in, xiv, 318 Connecting Nerve Cells, ix, 127, 128 (fig.), 129, 130; of brain, 148-9, 150-1 (see also Connector Neurones) Connective Tissue, ix, 13, 58-9; growth of, 287; in muscles, 75, 79; ligaments formed of, 71; making of, 54; scars formed by, 48, 287 Connective Tissue Skeleton, ix, 71-2 Connector Neurones, xi, 21; in brain, 31-2, 200; in spinal cord, 26; development in embryo, 35 (see also Connecting Nerve Cells) Conscious Life, parts concerned in, ix, 21-2 Consciousness, in mental life, xi, 47; habit and, 253-5; motor response and, 27-8, 123-4, 202; psychology as science of, 10-11; "stream" of, 193 Consequent Streams, xiv, 157, 174 Conservation, technical meaning, iv, 382 Conservation of Energy, iv, 40-1, vi, 128; establishment of doctrine, xvi, 131; remarks on doctrine, iv, 9 Conservation of Resources, coal, v, 172, viii, 283; forest, vi, 366, xiii, 9, 371-2, xiv, 382; petroleum supply, vii, 309; soil, xiv, 64 Constantinesco, George, v, 107-8 Constantin Metal, vi, 77 Constipation, causes and treatment, ix, 250-2; chronic, x, 316-17, 328-9; hyperacidity caused by, 322 Contact Catalysis, viii, 82-3, 103, 316 Contact Senses, ix, 86, 91-5; connections with brain, 142 Contempt, sentiment of, xi, 148 Continental Climates, i, 208, 370, xiv, 346, 347 Continental Islands, xiv, 271-6, 278-81 Continental Platforms, major relief features, xiv, 9, 27; margins and slopes, 25, 287-8 Continental Rivers, xiv, 153 Continental Shelves, iii, 52, xiv, 287; area covered by, iii, 52, xiv, 26; breadth of, 25, 285; cutting of, by waves, iii, 55-6, xiv, 46-7; deposits on, iii, 53, xiv, 284-5 Continental Slope, xiv, 287-8; deposits on, iii, 53 Continents, average elevation of, xiv, 26-7; climate on opposite sides, 346; distinction from islands, 23; drainage systems, 190; former connections, xiii, 320, xiv, 290; former submergence, iii, 216, xiv, 19-20; present, never covered by deep sea, iii, 55; rate of wearing away, xiv, 41; tides modified by, 292 Continuity, of action, xi, 264-5; of training, 257 Contrast, association by, xi, 197; attention aroused by, 344; effect on tastes, 72; illusions of, 189 Convection, iv, 139, 178-9, 185 Converters, electrical, vi, 162, 332-48, vii, 365; speed-limiting devices, 48; in traction systems, 199, 365 Convolutions of Brain, xv, 62, 63, xi, 29 Convulsions, production of, ix, 133-4 Cook, Capt. James, xvi, 123; story of Polynesian, xv, 124 Cooke, Dr. R. P., x, 161 Cooking, chemistry of, viii, 367-9; development of art of, xv, 13, 195, 232-3; effect on vitamines, ix, 36, x, 263, 266; frying habit, ix, 286; good, advantages to digestion, 241-2; "pressure cookers," iv, 171; use and advantages, xv, 229 Cooking (electric), vii, 89; special rates for, 174; in U. S. Navy, 332-3 Cooking Utensils, aluminum, viii, 155; copper, 164 Coolidge Tube, x, 185 Cooling, contraction by, iv, 134-5, viii, 107-8; dynamic, i, 90 (see also Expansion, cooling by); use of water in, viii, 37; water changes in, iv, 149, 150-1, viii, 38 (see also Refrigeration) Coon Bear, xii, 338 Cooper, Astley, x, 129-30 Coordinates, iv, 16 Copal, in varnishes, viii, 265 Copepods, xii, 18, 84 Copernican Theory, ii, 43-4; aided by Pythagorean teachings, xvi, 82; establishment of, iv, 95; Galileo and, ii, 54, 56; Kepler, and, 49; not accepted at once, 45, 46, 60, 311 Copernicus, ii, 42-4, iv, 19, xvi, 102; as astrologer, ii, 21; "De Revolutionibus," 12, 43; ideas of motion, 63; on speed and orbits of planets, 49; studies in Italy, 12 Copper, affinity intensity, viii, 128, 164; alloys, 164, 171, 273; atomic weight and symbol, 383; density of, iv, 113; electrical conductivity, iv, 283, vi, 77, 79, 80, viii, 164; electrical positiveness, vi, 59; electric welding of, iv, 312; electrochemical analysis, viii, 295; extraction methods, 270-1; fungicide uses, 170; formerly mined in New Jersey, xiv, 112; heat conductivity, iv, 176, 179; melting point and requirements, 162, viii, 384; name, origin of, xv, 157; native, iii, 327; occurrence and production, 360-2, viii, 129, 130-1, 163, 198, xiv, 237, 288; refining of, vii, 319-20, viii, 166-7, 272; specific heat of, iv, 155; specific gravity, viii, 384; tests for, 286, 287, 288; uses, iii, 359-60, viii, 126-7, 163-4, 167; valences of, 94, 189 Copper Bromide, color, viii, 123 Copper Chloride, color, viii, 123; electrolysis of, 124 Copperhead Snakes, xii, 233 Copper-Plating, vii, 314-15, 317-18, viii, 165-6 Copper Pyrites, iii, 326 Copper Smelting, smoke precipitation, vii, 347 Copper Sulphate, color, viii, 123; electrolysis of, 125; uses, 146, 332; used in Egyptian medicine, x, 12; water and, mixture of, iv, 131 Copper Wire, for electrical transmission, vi, 77, 79, 80, vii, 20, 22-3, 104; standard tables, 378-80; table of carrying capacities, 381 Copra, xiii, 220, xv, 125 Coquina Rock, viii, 152 Coral Reefs, xii, 40-2, xiv, 263-4; formed in shallow water, iii, 53, xiv, 276; oceanic islands built of, 276, 277; temperature limitations, 263-4, 305, xii, 40 Corals, iii, 259, 266, 267-8, xii, 38-43; calcium carbonate in, viii, 151; false, xii, 47 Coral Snakes, xii, 213, 225-6 Corbeil, Gilles de, x, 37 Corcovado Peak, xiv, 112 Cordage, sources, xiii, 238-41 Cordaitales, xiii, 310, 317 Cordaites, iii, 255, 256 Cordova, university of, xvi, 100 Cores, in electric machines, vii, 365 Cork, specific gravity of, iv, 109, 112 Cormorants, xii, 253; fish-catching with, xv, 223-4 Corn, American origin, xiii, 182, 211, 212, 221, 222; economic importance, 208; food value, viii, 364, 365, x, 262, 278, 279; grains of, fruits, xiii, 56; in grass family, 179; leaves of, 32, 176; monocotyledon, 178; stalks, glucose from, ix, 230; stalk structure, xiii, 26; starch manufacture from, viii, 243; time to plant, i, 255; tryptophane in, viii, 351; weather best for, i, 245-8 (see also Indian Corn) Corn Crakes, xii, 262 Cornea, of eye, ix, 109, 110 (fig.), xi, 84, 85; astigmatism of, ix, 113-14; no warm spots in, xi, 112 Cornets, iv, 231 Corn Flour, vitamines in, x, 267 Corn-Harvesting Machines, v, 249 Corn Syrup, as food, ix, 292; vitamines in, x, 262 Corolla, xiii, 45; absent in some plants, 46, 182; evolution of, 201 Corona Discharge (electricity), vii, 10-11, 23 Corona of Sun, ii, 219-26, 184; appearance in eclipses, 213-14; comets and, 281; photographic studies, 128, 129; rotation, 121; study of, proposed method, 225-6; study in various eclipses, 211-12, 214, 218 Coronas, atmospheric, i, 183-4, 370 Coronium, discovery, ii, 211, 223 Corposants, i, 157-8 Corrasion, defined, iii, 29; by ice, 63-4; by sand, 72; in Grand Canyon, 40; potholes formed by, 39-40 Correlation, mathematical, i, 253 Correlation of Energy, iv, 40 Corries, of Scotland, xiv, 58 Corrigan, John, x, 112 Corrosion, chemical, viii, 10, 13, 100; Electrolytic (see Electrolytic Corrosion) Corrosive Sublimate, viii, 170 Cort, Henry, v, 316 Corti, Organ of, xi, 102 Corundum, iii, 327-8 Corvisart, x, 110 Corymb, flower-form, xiii, 50 Coryza, x, 295, 341 Cos, School of, x, 21-2; influence in middle ages, 37 Cosmogony, defined, ii, 362; theories, ancient and modern, 366-84, xvi, 58, 76-9, 80, 81-2, 84 Cossacks, bows and arrows of, xv, 214 Cotopaxi, Mount, xiv, 225 Cotton, as clothing material, ix, 311, x, 307, 308, 309; cultivation, xiii, 238; dyes for, viii, 259; fiber, 229, 254, ix, 30, xiii, 237; fiber to fabric, v, 269-83; humidity effects, i, 78; importance, xiii, 208, 235, 236; kinds, v, 269, xiii, 236; Mediterranean origin, xxiv, 382; mercerized, viii, 255; preparation for manufacture, xiii, 237-8; removal of, from wool, viii, 255; vegetable silk from, 255-6 Cotton Cloth, making of, v, 269-83 Cotton Crop, forecasts, i, 251 Cotton Gin, Macarthy's, xiii, 238; Whitney's v, 269-71, 376 Cotton Plant, xiii, 236-7 Cotton Seed, uses, xiii, 238 Cottonseed Oil, viii, 246; solidified, 232, 247 Cottrell, Dr., vii, 216 Cotyledons, xiii, 60; classification by, 176 Cougars, xii, 363 Coughing, reflex action, ix, 135, 258, xi, 20 Coulomb, electric quantity unit, iv, 280, 284, vi, 17, 69, 82, vii, 365, 374 Coulomb, C. A., electrical work, vi, 17-18, xvi, 122; quantity unit named for, iv, 280 Countertrade Winds, i, 130, 366 Counter Voltage, vii, 365; in motors, vi, 226-8, 232, 233, 236 Counting (see Numbers) Country Rock, definition and character, xiv, 105 Courage, motor origin, xi, 61 Courtship, among animals and birds, xv, 274-5 Cows, domesticating qualities, xv, 197; fat production by, ix, 298; milking by electricity, vii, 222, 226-7 Cow's Milk, for infants, ix, 33-4, 346 Cowries, xii, 73 Coyote, xii, 340 Crabs, iii, 260, 276, 279, xii, 85-7; deep sea, 23; hard and soft-shelled, 83; "no-body," 89; sponges and, 32 Cramps, from cold baths, ix, 313; significance, xi, 120 Cranberry, bogs, xiii, 382; origin, 225; ovary, 202 Cranes, (birds), xii, 262 Cranes, hydraulic, v, 101-2, 106 Cranial Nerves, ix, 131, 132, 142, xi, 29-31, 76; doggerel verse on, 214 Crater Lakes, iii, 155, xiv, 101, 203 Craters, formation of, xiv, 101-2; of Hawaiian volcanoes, iii, 104, 105, xiv, 322; of Mount Katmai, iii, 101, (fig.) Crawfish, xii, 87 Creation, ancient conceptions, ii, 366, xvi, 77 Creative Imagination, xi, 225-7 Creepers (birds), xii, 268 Creeping Speedwell, xiii, 28 Creodonts, xii, 332, 339, 366, 375 Creosote, constituents, viii, 333; source, xiii, 255 Crepuscular Rays, i, 169, 370 Cress, xiii, 197, 222 Cresylic Acid, viii, 238, 253, 333 Cretaceous Peneplain, iii, 232 Cretaceous Period, iii, 214-20; animals and plants of, 20, 256-7, 266, 295-6, 292, 297, xii, 154, 202, 210, 242-3, 275; first mammals in, xv, 71 Crete, ancient meteor in, ii, 284; early civilization of, xiv, 281; elevation changes, 33; Phaestos disk, xv, 176 (fig.) Cretinism, x, 350 Crevasses, formation, iii, 63; cirques from, 66 Crex Rugs, xiii, 188, 236 Cribo, (snake), xii, 219 Crickets, xii, 110 Crile, Dr. George W., on emotion effects, xi, 135-6; on fear in animals, 136; on kinetic system, 57-60; on laughter, 355, 356; on pain, 119, 120; on suppressed desires, 141-2 Crime, hypnosis and, xi, 320; of crowds, 329-31; punishment of, among primitive peoples, xv, 369-75, 379-80; street lighting and, vi, 279 Crinoids, xii, 23, 49 Cripple Creek Gold District, iii, 367 Crisis, in diseases, Hippocratic doctrine, x, 21 Critical Period, of crops, i, 248-50, 370 Critical Pressure, iv, 171-3 Critical Temperatures, i, 29, iv, 171-2, viii, 303-4; of various substances, iv, 173 Crocker Land, i, 173 Crocodiles, xii, 182, 196, 198-202; resemblance to tuatera, 184; sleeping sickness due to, x, 169; ziczacs and, xii, 263 Cro-Magnons, xv, 99-102, xvi, 50; art of, xv, 110-21; implements of, 109 Crompton, mule-spinner of, v, 274, 376 Cromwell, sea captain, v, 305 Crookes, Sir William, cathode ray studies, x, 184, xvi, 165, 193; on nitrogen needs, i, 34; theory of fourth state of matter, iv, 54-5, xvi, 193; vacuum tubes named for, iv, 317 Crookes Tube, iv, 317, vi, 114, vii, 251; electron study in, xvi, 193; fluorescence in, iv, 380; phenomena of, 50; X-ray discovery and uses, x, 184, 185 Crop Forecasts, i, 250-2 Crops, critical period, i, 248-50, 370; rotation of, viii, 342-6; sun spots and, ii, 186; weather and, i, 245-50, 252-3 Crossbows, xv, 215 Crosses, inheritance of characters in, ix, 333-7, x, 231-2, xiii, 332 Crossfell, helm and bar of, i, 105, 374 Cross Fertilization (plants), methods to insure, xiii, 120-54; variations due to, 331-3 Croton Bugs, xii, 107 Croton Dam, iv, 119, 120 (fig.) Croup, antitoxin in, x, 298 Crowberry, spread of, xiii, 342 Crow Blackbird, coloring of, xii, 245 Crowd-poisoning, i, 321 Crowds, psychology of, xi, 323-33; leaders of, 332-3; legal responsibility, 329-31 Crucibles, graphite, viii, 43; platinum, 173 Crucible Steel Process, vii, 312 Cruickshank, William, electrical work, xvi, 122 Cruickshank, Wm. Cumberland, medical work, xvi, 179 Crusaders, coffee not known to, xiii, 232; heroic crowds, xi, 326; paper introduced by, v, 290 Crusades, effect on medicine, x, 37; horse improvement by, xii, 307 Crust of Earth, xiv, 16; chemical constituents, iii, 308, viii, 19, 90, 118, 129, 138-9, 148, 190-1, 192; chemistry of, 190-203; layers in, 191-2; movements, iii, 76-98, xiv, 31-2, 33-9, 341 (see also Earth Movements); rocks in iii, 12-14, 110-12, xiv, 17-19; settling, cause of brontides, 196; specific gravity, xiv, 11; theory of formation, iii, 160; thickness, 17, viii, 191-2; waters in, iii, 113-29 Cryptograms, xiii, 63; cycads and, 309; earliest plants, 303; forests of, of Silurian, xv, 71; in coal age, xiii, 310; numbers, 168; reproductive process, 154-65; spore-dispersal by wind, 344; water necessary to fertilization, 300 (see Flowerless Plants) Crystalline Form, iii, 309-11, viii, 203, 312-13; solidification in relation to, iv, 163 Crystalline Rocks, iii, 378; of oldest eras, 169, 170-1, 189 Crystals, Crystallization, iii, 309-20, 377-8; cleavage, 310, 318, viii, 202; electrification by cleavage of, iv, 260; growth, iii, 311, 316; growth of alum, viii, 313; light polarization by, iii, 319-20, iv, 354; Mitscherlich's studies, xvi, 161; Pasteur's studies, 163-4; snow and ice, i, 115-16; water of, viii, 38; X-ray studies, iii, 311, viii, 313 Ctesibius, discovery of compressed air, v, 109-11; ignorant of atmospheric pressure, 112; inventions and theories, xvi, 91-2; water clocks, v, 59-62 Cuba, almiquis of, xii, 367; American occupation, x, 160; earthquakes in, xiv, 331; jute production, xiii, 241; sugar production, 215; tobacco production, 258; yellow fever eradication, x, 160-2, xiv, 356; zoölogy of, 274-5 Cuckoos, xii, 255-6 Cucumbers, as food, viii, 365; origin, xiii, 223 Cud Animals, xii, 311-12 Cugnot, Joseph, v, 207 Culinary Paradox, iv, 168-9 Cullen, Dr., refrigerating machine, v, 350, 354-6 Cullen, William, x, 88 Cultivated Plants, birthrate in, xiii, 51; original sources, 221-7, xiv, 381-2 (see also Garden Plants) Cultivation (soil), reason for, xiii, 92 Cultural Advance, requisites of, x, 107 Cumberland Plateau, xiv, 221; height, 27 Cumberland Valley, xiv, 167 Cumene, viii, 235, 253 Cumulo-Nimbus Clouds, i, 102, 103-4 Cumulus Clouds, 1, 98, 101-2, 103-4; air currents and, 293; formation of, 93 Cuneiform Writing, xv, 174, 175 (figs.), xvi, 60 Curassows, xii, 261 Curie, Madame, radium discovery, xvi, 193 Curiosity, instinct of, xi, 55; of crowds, 328 Curlews, xii, 262 Currents (water) power of, iii, 30-1, xiv, 39, 52-3 Current Transformers, vii, 44 Current Wheels, v, 76 Curtis, on spiral nebulæ, ii, 362 Curtis Turbines, v, 151, 152, 382 Curved Motion, forces producing, iv, 72-3 Curves, pitching of, iv, 67-9 Cusa, Nicolas de, xvi, 102 Custom, Cicero on, x, 135; modesty and, xv, 254-5; morality and, 286; obedience to, how enforced, 374-5; crowd psychology in, xi, 333 Customs Examinations, by X-rays, vii, 256-7 Cut-off, of steam engine, v, 146-7, 208 Cutting of Metals, v, 46-7, 54-5, 383; by oxygen jet, i, 33 Cuttings, (plants) propagation by, ix, 337, xiii, 166, 167 Cutting Tools, of ancient Egypt, xvi, 66-7 Cuttlebone, xii, 79 Cuttlefish, iii, 260, 275-6, xii, 58, 78-9 Cuvier, biological works, xvi, 139, 148; work on paleontology, 168 Cyanamide Process, i, 36, viii, 74, 153 Cyanide Solution, vii, 317 Cyanogen, xvi, 160 Cycads, iii, 251, 255, xiii, 309, 316, 317 Cycles, chemical, viii, 334-5, 349-50 (see also Carbon, Hydrogen, nitrogen Cycles) Cycles, geographical and geological, xiv, 29 (see also Cycles of Erosion) Cycles, of alternating currents, vi, 153, 154-5; degrees of, 204 Cycles of Erosion, in land surfaces, iii, 33-6, xiv, 30, 34-5, 47-9, 155-64; in mountains, iii, 135-6; in shore lines, 56-7, xiv, 254-5 Cyclones, i, 135-8, 370, xiv, 349-50; electrification by, vii, 212-13; handling of ships in, i, 277-8 Cyclonic Thunderstorms, i, 138, 151 Cyclonopathy, i, 330, 370 Cyclonoscopes, i, 279, 370 Cyclops, (crustacean), xii, 84 Cygni, 61, measurement of distance, ii, 16, 315; parallax, 311-12 Cygnus, nebulæ in, ii, 360; new star in, 332 Cylinders, boring of, v, 44-5; cooling, 159-61, 166-7; in internal combustion engines, 157-61, 166-7; of steam engine, 147; pressure in, iv, 119 Cyme, flower form, xiii, 50 Cynodictis, xii, 346-7 Cypress Trees, in landscaping, xiii, 270; in southern forest, xiv, 372 Czecho-Slovakia, public health fellowships, x, 172; stone age remains in, 108 (fig.) Daboia, xii, 231 Daddy Longlegs, xii, 90 Da Gama, Vasco, xiv, 309, 351 Daggers, development of, xv, 212 Daguerre, ii, 125 Daimler, Gottlieb, v, 213, 382 Dairies, electricity in, vii, 226-7 Dairy Products, drain on farm of, viii, 342-3 Daisies, flowers of, xiii, 49-50; introduction to America, 353-4; seed dispersal, 58-9; stems, 23 Daisy Family, xiii, 206; fertilization in, 144; flower forms, 44 (fig.); fossil species, 324; in New Zealand, 380; in pampas, 376; original home and spread, 350, 353; petal arrangement, 190; seed dispersal, 344, 345 Dakin, antiseptic solutions of, x, 181-3, 382 Dakota Sandstone Formation, iii, 114, 115 (fig.) Dalmatia, coast of, xiv, 252, 257; harbors of, 268 Dalton, John, xi, 93, xvi, 133, 160, 162 Daltonism, inheritance of, ix, 340 Damaraland, desert plant of, xiii, 380 Damascus, swords of, v, 315 Damped Waves, vii, 264, 273, 286-8, 290 Dampier, William, i, 130, xvi, 114 Damping, in meters, vii, 159 Dams, beaver, xii, 295-6; use of, v, 76, vi, 361, 364 Damsel Flies, xii, 105 Dances, Indian, xv, 305-6; primitive, 310-12, 313, 316 Dandelion, family of, xiii, 206; flower of, 49; origin, 223, 353-4; roots, 16; seed dispersal, 58-9, 344 Daniell Cell, viii, 167 Dante, skull capacity, xv, 40 Danube River, delta of, xiv, 185; historical importance, xv, 138-9; longitudinal character, xiv, 154; varied course, 155 Danzig, Poland and, xiv, 306 Darby, Abraham, v, 316 Dardanelles, important to Russia, xiv, 267 Dardanelles Expedition, i, 308 Dark Days, i, 56-7, ii, 211 Darkness, distinguishing of, by primitive animals, ix, 105; effect on plants, xiii, 72, 76, 77, 84-90; effects on plants, animals, and man, x, 253; from interferences of light, iv, 377-8; horrors of world of, 51; periodic seeking of, xi, 52-3; sleep and, 282, 288; tuberculosis germ and, x, 290, 291 Dark Segments, i, 167, 371 Darning Needles (flies), xii, 105 Darwin, Charles Robert, x, 134-6, xv, 15; book on fertilization of orchids, xiii, 145; book on restless plants, 110; epigenesis theory, xvi, 118; experiment on destruction of seedlings, xv, 21; experiment with tendrils, xiii, 112; naturalist on "Beagle," 224, x, 134-5, xvi, 142; on descent of man, xv, 56; on emotions, xi, 131-3; on expression of emotions by animals, xv, 64-5; on fossil record, xiii, 302; on Madagascar orchid, 48; on self-fertilization, 135; on sexual selection, xv, 274; on variations, 334; "Origin of Species," x, 135, xiii, 334, xvi, 148, 167, 181-2; skull capacity, xv, 40 (see also Darwinian Theory) Darwin, Erasmus, x, 134, xvi, 148 Darwin, George H., tidal friction theory, ii, 375-6, 377, 156-7 Darwinian Theory, x, 135, 136, xv, 15, 24-5, 56, xvi, 149-51, 152; Bagehot on changes wrought by, xvi, 198; Greek anticipation of, 79; horror first caused by, xv, 53; naturalism and, xvi, 111; philosophical effects of, 195 Dassies, South African, xii, 304 Dasyures, xii, 278 Date Palm Tree, xv, 125 David's Deer, xii, 316 Davos, health resort, i, 210, 325 Davy, Edmund, xvi, 190 Davy, Sir Humphry, electrical work, vi, 16, 19, xvi, 122, 189; heat studies, iv, 43, xvi, 131; laughing gas discovery, x, 123-4, 125 Day, divisions of, v, 57, xvi, 57; mean solar, iv, 15-16; periods of high and low temperatures, i, 76, xiv, 347-8; periods of highest energy, xi, 277 Day and Night Breezes, i, 131 Dayflies, xii, 104 Dead Reckoning, v, 65-6 Dead Sea, formation of basin, iii, 151, xiv, 118, 120-1; level and level changes, iii, 151-2, xiv, 121, 205, 362; salinity, iii, 152, viii, 139, xiv, 207 Deaf and Dumb, sign language of, xv, 148, 150 Deafness, ix, 103-4; from brain disease, 146 Death, correlative of life, xii, 13; "irritability" theory of, x, 86, 87; James on phenomena of approaching, 242; physiological meaning, ix, 17; primitive conceptions of, xv, 327-9, 331-8; vital knot in relation to, ix, 257 Death Adders, xii, 229 Debtors, treatment of, in African tribes, xv, 370 De Candolle, plant classification, xvi, 165-6; vegetable table, xiii, 221 Decay, air and, xiii, 312-18; carbon dioxide from, viii, 49, 61; humus produced by, 340; nitrogen from, 73, 346; phosphorescence from, i, 346, 349, xii, 20 Deccan of India, lava fields, iii, 105, 228, xiv, 103 Deciduous Trees, xiii, 175, 269, 271-2; of temperate forests, xiv, 370, 371, 372, 373, 374 Decimal System, xv, 181 Declination, of compass needle, iv, 247 Declination of Stars, ii, 299 Decomposition, (chemical), viii, 12, 101; contrasted with dissociation, 121; double, 104-5; of salts, 117 Decrement, of oscillating currents, vii, 286, 287-8 Deeps, ocean, iii, 52, xiv, 9, 23, 286; volcanoes and, 316 Deep Sea, animal life in, xii, 21-4; animals, luminosity of, 139; conditions of life in, 21-2; darkness of, 22, xiv, 298; density of, xii, 21; deposits, iii, 54-5, xiv, 285, 286; fish of, xi, 53, xii, 20, 23-4, 136, 138-9, 163, xvi, 146; ground sharks of, xii, 143, 147; movement of water in, xiv, 284, 298-9; never over present continents, iii, 55; ooze, xii, 18, 19; plants of, 16-17; seaweeds not found in, xiii, 72; soundings of, xiv, 284; temperature, 297, 298, 299; topographical features, 284, 286-7, 288-90; unknown to us, v, 202 Deer, xii, 317-20; evolution of hoofs, iii, 300; fear in, xi, 136; heart in, x, 332 Deer Family, xii, 315-20 Deer-hunting, in India, xv, 223 Defectives, human, increase in, xv, 27 De Forest, audion detector, xvi, 191 Degrees, electrical, vi, 204 De Haen, x, 77 Dejection, emotion of, xi, 146; posture and, 337, 338-40 (see also Despondency) DeLaval Steam Turbine, v, 148-50, 382 Delaware Indians, prayer song of, xv, 346-7 Delaware River, estuary of, xiv, 40; geological history, 40, 60, 168-9, 171; heterogeneous course, 155; rapids of, 159; shad season in, xii, 155; superimposed stream, iii, 233; transverse characters, xiv, 99, 154, 167; valley and gap, 50-1, 52, 169 Delaware Water Gap, iii, 233, xiv, 50-1, 167, 169; rock weathering at, 76 Delco Automobile System, vii, 137 Delco Power Sets, vii, 232 De Lesseps, Ferdinand, Saharan proposal, xiv, 205 Deliberation, after contact and distance sensations, ix, 95, 121, 140; nervous delays in, 140, 141, xi, 20, 21; value of, 139 Delirium, Brown on, x, 89; hot baths in, 311 Delta Connections (electric), vi, 210-11, 318, 325 Delphi, Oracle of, xv, 351-2 Deltas, iii, 32, xiv, 53; alluvial soil of, 70; coasts formed by, 53, 263; in lakes, 202, 210-11; lakes formed by, 203; rivers joined by, 185 Delusions, x, 358-9 Demagnetization, vi, 37-8, 117, vii, 366; by heat, iv, 253; test, vi, 43 Dementia Precox, x, 237 Democritus, on knowledge, xvi, 87; on matter, 83; on origin of earth, ii, 366-7 Demosthenes, timed speeches, v, 62 Denatured Alcohol, viii, 250 Dendrites, xi, 18, 19; receptors for pain, 117 Denmark, antiquity of man in, xv, 86-7; föhrden of, xiv, 259; forests and peat bogs, xv, 86-7 Density, absolute, iv, 110-11; methods of determining, 111-12; of liquids, how measured, 113, vi, 147; of various substances, iv, 113; specific, 111; standard of, 149 Densmore, James, v, 312 Dental Arches, xv, 98 (fig.) Dentistry, hypnosis in, xi, 316; protection against pain, 121 Denudation (see Erosion) Denver, boiling temperature in, iv, 170 Deodorants, inhibition in, xi, 81 Department Stores, Christmas lighting, vii, 342; pneumatic tubes in, iv, 130; rain and business, i, 265 Deperditometer, i, 319, 371 Depolarization, of electric cells, vi, 137, 139, vii, 366 Depression, of land and sea areas, (see Subsidence) Depressions, (geological) in land, xiv, 204-5; in ocean floor, 286 Depressions (meteorological), i, 135, 371 (see Lows) Depth, perception of, ix, 119-20, xi, 173-85 Derborence, lakes of, xiv, 202 Derived Proteins, viii, 352-3 Derived Units, iv, 46, xvi, 131 Dermographism, xi, 317 Dermoid Cysts, x, 120 Desault, Pierre, x, 91-2 Descartes, influence of, x, 67; mathematical and scientific work, ii, 15, xvi, 113-14, 118-19; theory of vortices, ii, 60 Descriptive Astronomy, development of, ii, 15-16, 113-14, 119, 139 Deserts, density of air over, i, 171; dust whirls, 60; evaporation in, 323; in trade wind belts, xiv, 355-6, 380; irrigation by sun-power, v, 178; lizards of, xii, 206; mirages, i, 172-3, 174, iv, 328-9; rainfall, i, 112; rainfall and plants, xiii, 377-81; rock weathering in, iii, 23, 71-3, xiv, 42, 77, 79; salt deposits, viii, 197; "stretching" of, xi, 173; water-storing plants, xiii, 28, 30, 41-2, 104, 106-7, 336 (illus.); wind action in, iii, 71-5 (see also Arid Regions) Desert Sounds, i, 196, 371 Desert Topography, xiv, 41-2 Design, elements of (prehistoric), xv, 299 Designs, enlargement of by lanterns, iv, 342 Desires, suppression of, xi, 140-2 (see also Suppressions) Despondency, indigestion and, xi, 370 (see also Dejection) Detectors, wireless, iv, 315-16, vii, 261, 268-70, 278-80; to guide ships, 284-5 Determiners, inheritance, ix, 329-42, x, 233-4, xiii, 330, xvi, 156 Detonation, of explosives, viii, 262 Detroit, steamers passing, xiv, 212 Devilfish, xii, 78, 148-50 Devil's Tower, Wyoming, iii, 111, 176 (Pl. 10), xiv, 129-30 Devil Whirlwinds, i, 60, 371 Devonian Period, iii, 20, 194-6, 378; "Age of Fishes," 283, xv, 71; animals and plants in, iii, 252, 271, 277, 278, 282-4, 285; extension of sea in, 192 (fig. 37) De Vries, variation studies, xvi, 153 Dew, i, 120-1, 371, xiii, 108; former belief about, i, 119; not formed on cloudy nights, iv, 183 Dewar, liquid air inventions, i, 31, vii, 323 Dewar Flask, viii, 68 Dew Bow, i, 177 Dew Point, i, 78, 79, 371 Dew Ponds, i, 352-3, 371 Dextrin, viii, 227-8; in bread crust, 368; molecules of, 356; production and uses, 241, 243, 244 Dholes, xii, 345 Diabetes, ix, 290, 293-4, x, 276, 330 Diablerets, peaks of, xiv, 202 Diagnosis, art and science of, x, 366-79; Brown's system, 89; chest, 99, 371; Egyptian study of, xvi, 70; of infectious diseases (serum method), x, 215-17; X-rays in, vii, 251, 254, 255, 256, x, 185-6, 372-4 Diamond Drills, v, 263, 264, 380; in ancient Egypt, xvi, 67 Diamonds, iii, 328, viii, 42-3; artificial, vii, 301, 311, xvi, 190; cathode ray effects, 193; cutting of, vii, 300, 309; electrification, vi, 12; in meteorites, ii, 292; X-ray tests, vii, 257 Diana of the Ephesians, ii, 284 Diarrhea, ix, 249, x, 253, 307, 328 Diastole, arterial, x, 62, 63-4, 65; of heart, 65 Diathermanous Bodies, iv, 182 Diatoms, deposits of, iii, 257-8, xiii, 67-8; in tripolite, iii, 335; in sea, xii, 17; oil from, iii, 349; oil storage by, ix, 28 Diatonic Scale, iv, 207 Dichloramin-T., x, 183, 382 Dicotyledons, xiii, 60; antiquity, 207; leaves and flowers, 176, 178; leaves and stems, 177 (fig.); subdivisions, 180, 189-90; various families, 189-205 Dictation, memory after-images in, xi, 220 Dieffenbach, Johann Friedrich, x, 130 Dielectric, of condensers, iv, 264, vi, 302, 305, vii, 366; in lightning, 206; losses due to imperfect, 297-8; strain, 366 Diesel Engines, v, 161-2, 382; efficiency, 164; fuel, 156; in submarines, 199 Diet, bile in relation to, ix, 275; deficiency of, diseases from, x, 255-68, 276; fads of, ix, 285-6; fats and proteins in, 300-1; for reducing weight, 301-2; mixed, man adapted to, 246, 285-6; natural regulation of, 301, x, 255, 257; need of amino acids in, 278; nutrients in daily, viii, 366-7; starch foods in ordinary, ix, 290, 300 (see also Foods, Nutrition) Difform Motion, ii, 80 Diffraction of light, iv, 326, 378; optical phenomena, i, 183-5 Diffraction of sound, iv, 52, 236-7 Digestion, ix, 226-46, x, 319-30, 353; benefited by savory food, ix, 98, 241-2; chemistry of, viii, 356-8; color effects, xi, 96; emotion effects on, ix, 165, 241; enzymes in, viii, 103, 357 (see Enzymes); excitement effects, xi, 374-5; exercise and, 339; fried foods and, ix, 286; fruit stimulation of, viii, 365; glucose in, 225-6; historical studies of, ix, 239-40, x, 121, 128; hot baths and, ix, 313; in men and plants, xiii, 109; of proteins, x, 204; sleep in relation to, ix, 219, xi, 285; soups as aid to, ix, 241, x, 320 (see also Indigestion) Digging with water jets, v, 88 Digitalis, source, xiii, 256; use of, in heart diseases, x, 333, 383 Dikes (geological), iii, 13, 110-11, 378, xiv, 106-8; columns in, 130; illustrations, iii, 102, 160 (Pl. 9); veins and, 383-4 Dilated Stomach, ix, 85 Dimension, illusions of, xi, 186, 188, 189; perception of, 162, 165, 171-2, 172-83 Dining rooms, lighting, vi, 275-6, vii, 69-70 Dinosaurs, iii, 288-93, 304 (Pl. 17), xii, 182, 194-5 Diœcious Plants, xiii, 47 Dionysus, worship of, xv, 352 Diophantus, xvi, 95 Dioptra, of Ctesibius, xvi, 91 Diphenyl, viii, 240 Dipper (constellation), moving clusters in, ii, 343 Diphtheria, x, 296-8; antitoxin of, 197, 212, 213-14, 218, 296-8; immunity to, 207, 298; named by Bretonneau, 110; toxin of, 196, 197 Direct Current Generators, iv, 307-8, vi, 159, 175-94, 344; commutators on, vii, 364-5; employment, vi, 215; voltages, 159 Direct Current Motors, vi, 217-39; in traction, vii, 182-3, 198-200; on farms, 224; speed flexibility, vi, 224-6, 229, 230, 232, 240-1 Direct Currents, vi, 152, 153-4, vii, 365; ammeters for, vii, 166-72; circuit-breakers for, 37, 39, 40; conversion from alternating, vi, 330-48; generation (See Direct Current Generators); inductance in, 166; lighting and magnetic effects, 155, 156-7; open-circuited by condensers, 170, 304; power consumed by, 165; transformers unusable, 309; transmission by, 160, 161, 195, 332; uses, 152, 332; used in electric furnaces, vii, 305-6; used in electrochemistry, vi, 163; used in electrotherapy, vii, 244; used in smoke precipitation, vi, 164; used in traction, 161-2, vii, 182, 186, 195; value of current flow, vi, 164-5 (see Ohm's Law); voltages, vii, 164; voltages, production of high, 349-50; voltmeters for, 154-65; wattmeters for, 172, 173, 175 Direct Lighting, xi, 277, 373 Direction, perception of, ix, 117-18, 120, xi, 165, 167-71 Directional Wireless, i, 291, 302 Dirigible Balloons, iv, 107-8, v, 226-30, 382; in forest service, i, 49 Disaccharides, viii, 224, 226-7, 375; enzyme of, 357 Discomfort, atmospheric, i, 318, 320, 322; senses of, in infants, ix, 351 Discordant Coasts, xiv, 249 Discouragement, conquering of, xi, 337-40 (see also Dejection, Despondency) Discoveries, accidental, xv, 212-13, 232, 241-2; great, usual way of, x, 40; priority in scientific, 122 Disease Germs, x, 193-226, xiii, 71; body resistance to, ix, 177-9, 185-7, x, 197-8, 203-12, xi, 34; campaign against, x, 285-315; discovery of, x, 194, 381, xvi, 143; identification of, x, 150, 215-17; in air, danger from, i, 325-6; in sewage, viii, 326, 328; in water supplies, 41, 318, 319; man's struggle with, xv, 25-6; "portals of entry," x, 198, 201-2. (See also Infectious Diseases) Diseases, anciently ascribed to spirits, x, 12; atmospheric electricity and, i, 330; "atom" theory of, x, 26; Brunonian theory of, 89; causes and factors other than infection, 227-81, 283; causes of infectious, 193-226; causes of, historical conceptions, 380; climatic treatment, i, 331, x, 383; diagnosis, (see Diagnosis); electric treatment (see Electro-therapeutics); habit in, xi, 248; Hoffmann's nervous fluid theory, x, 85-6; Humoral Doctrine of, 21; hypnotic treatment, xi, 319; infectious (see Infectious Diseases); James on, x, 244; lesion differentiated from, 98; living causes, 193-226; Locke on curing of, 75; manifestations of, in organs, 318-65; mechanical theory of, 23, 70, 71; mental, 354-65; mental factors in, 242-4; metabolism, effects of, ix, 179, 302-4; nature in cure of, x, 21, 73, 75-6, 84-5, 367; occupational, 244-6; Paracelsus on causes of, 48-9; pneumatic theory, 26-7, 29; prevention of, 282-317, xv, 49; Pythagorean theory of, x, 18; racial susceptibility to, xv, 47-52; recognition of, x, 366-76; savage conceptions and treatment, xv, 352-3, 359; solidistic theory, x, 25-6; specific, 196; sthenic and asthenic, 89; spread by tainted water, xiv, 140; suppressed emotions and, xi, 140, 141; Sydenham on meaning of, x, 73; Sylvius's chemical theory of, 69; thirst unimpaired in, ix, 89; treatment of, x, 379-84 (see also Therapy); tropical, xiv, 356-7, xv, 49-50; Van Helmont's conception of, x, 68; (see also Disease Germs) Disgust, in various sentiments, xi, 146, 148 Disinfectants, viii, 332-3; chlorine, 86, 274, 333; formaldehyde, 219, 333; hydrogen peroxide, viii, 41; mercuric, 170, 333; ozone, vii, 354; sulphur dioxide, viii, 78, 333 Dismal Swamp, coal-forming conditions in, iii, 199 Displacement Currents, vi, 302, 305 Display Lighting, vi, 280, vii, 339-43; colors in, iv, 51; psychology of, xi, 344, 345, 346 Dispositions, sour and sunny, xi, 55 Dissection of human bodies, x, 30, 41-2, 45, 81 Dissociation, chemical, viii, 120, 121, 122, 375 Dissociation of Ideas, xi, 206, 209; in mental troubles, x, 355, 360-1, 365 Distance, method of measuring, ii, 197-8; perception of, ix, 118-19, 120, xi, 165-9, 173-89; units of, iv, 283 Distance Senses, ix, 86, 96-121; choice in relation to, 121, 140; connections with brain, 142 Distillation, alcoholic, viii, 249-50; apparatus, 213 (fig.); fractional, i, 32, iv, 168 Distillation of coal, vii, 252-3 Distractions, fatigue from, xi, 277 Distress Signals, vii, 284 Ditch Grass, fertilization, xiii, 151-2 Ditching Machines, v, 216, 253, 254-5 Divers, compression and decompression, v, 120-1; pressure on, i, 329 Diversion, need of, in brain work, ix, 138 Diving Bells, v, 115-16, 121 Divining Rods, iii, 123-4 Division of Labor, first form of, xv, 279; in plants, xiii, 61-2 Divorce, xv, 290-1 Dizziness, from over-ventilation of lungs, ix, 266-7; sensation of, xi, 64 "Doctor" Winds, i, 131, 371 Dodder, plant, xiii, 100, 101 (fig.) Dodo, xii, 265 Dog Family, xii, 338-46 Dogfish, xii, 143, 146; eggs of, 140; name changed, i, 224 Dogs, xii, 344-6; baboons and, 380; canine teeth of, 333; cat's hatred for, origin of, 355; domestication of, xii, 345-6, xv, 197, 198; embryological resemblances, 54; employment in hunting, 223; expression of emotions by, 64; heat-loss regulation by, ix, 307-8; hyenas and, xii, 351; imitation in, xv, 66; language methods of, 141; mode of attack, xii, 354; reasoning power in, xv, 68; sense of smell in, ix, 97, 117; wild, xii, 344-5; zoölogical interest, xvi, 16 Dogwood, xiii, 271; flowering, 45; index plant, i, 255 Doldrums, i, 127, 129, 136, 371, xiv, 348, 349 Dollond, telescopes, ii, 100, 103, xvi, 125 Dolomite, viii, 149; in refractories, vii, 307 Dolphins, xii, 297 Domestic Animals, development of, xii, 345-6, xv, 197-8 Dominants, in crosses, ix, 334, 335, x, 231, 233 Donati's Comet, ii, 275, 277, 280-1 Donkeys, xii, 308 Door-checks, pneumatic, v, 134 Doppler's Principle, ii, 119, iv, 209-10; astronomical applications, ii, 123, 129, 133, 363 Dormice, xii, 291 Double Decomposition, viii, 104-5, 375 Double Images, xi, 175-81 Double Stars, ii, 122-4, 334-5; colors, 296; connections, 340; proportion of, 320; telescopes required for, 97-8; theory of origin, 377 (see also Binary Stars) Doubt, reasoning and, xi, 239-40; retardization of impulses in, 20 Douglas Fir, forests, xiii, 340, xiv, 374 Dover, England, breakwater, xiv, 301 Doves, mating of, xv, 276; plumage of neck, xii, 245 (see also pigeons) Down, character of, xii, 244; warmth of, x, 309 Downs of England, dew ponds, i, 352-3 Dowry System, xv, 285 Dragon Flies, xii, 105-6; ancient, iii, 279, xiii, 308; eyes of, xii, 102 Dragon Tree, xiii, 183-4 Drainage Systems, continental, xiv, 189-90; development stages, iii, 33-4, xiv, 48, 49, 155; earthquake effects, 335; Ice Age changes, iii, 243-5, xiv, 60-1, 170-1; joints and, 131 Drake, Daniel, x, 116 Drama, origin and development of, xv, 303-10, 322, 325; sentiment in, xi, 151 Draper, Dr. Henry, astronomical work, ii, 17, 114, 116, 126, 130, 134, 135, 307, 358; reflectors of, 103, 106 Draper Catalogue of Star Spectra, ii, 116-18, 146, 307, 309, 310 Dravidians, of India, xvi, 53 Drawing, development of art of, xv, 296, 298-9 Drawing Rolls, Arkwright's, v, 273-4, 376 Dreams, xi, 292-302; images of, 221; primitive conception of, xv, 328-9, 358; psychoanalysis of, x, 364-5 Dredges, modern, v, 255-9, 381; walking-machine, 216 Dried Foods, viii, 371; antiscurvy vitamines in, x, 262, 266 Drift, Glacial, iii, 378 (see Glacial Debris) Drills, ancient Egyptian, xvi, 67; core, v, 263; diamond, 263, 264, 380; metal-cutting by, 47; multiple, 53 (see Multiple Drills); oil, v, 265-7; pneumatic, i, 27, iv, 129, v, 129-30, 261-2, 263, 380, 381; rock, 129, 261-2; sonic-wave, 108; spiral chisels, 46 Dropsy, polyuria in disappearance of, x, 344; Van Helmont's idea of, 68 Droughts, i, 79, 371; financial panics and, 263; records of, in tree rings, xiii, 25; springs and wells in, xiv, 136, 138 Drowned Valleys, iii, 37, 378, xiv, 40, 164, 255-6; as harbors, 268 Drugs, blood riddance of, ix, 274; coal tar, viii, 253; in mother's blood, effects, ix, 343-4; plant sources, xiii, 249-55; pure food law on, viii, 370; taste deadening by, xi, 72; use of, in medicine, x, 21-2, 22-3, 30, 44, 45, 75-6, 77-8, 380-1, xvi, 109, 186-7 Drumlins, iii, 69, xiv, 60 Drums, xv, 316; African, 313 (fig.) Drupes, xiii, 54, 194 Dry Cells, iv, 297-8, vi, 59, 126, 127, 138, 143-4 Dry Docks, floating of ships in, v, 95 Dry Fogs, i, 96, 371; of 1783, 57, 58-9 Dry Fruits, xiii, 54, 55-6, 57 Drying Machines, iv, 73 Dry Steam, v, 140 Duckbills, xii 272, 273 Ducks, xii, 257-8; darkness effects on, x, 253; primitive methods of hunting, xv, 222 Duckweed, xiii, 31 Ductless Glands, x, 346-53; secretions used in therapy, 382 Dufrausne, x, 181 Duluth, Lake, iii, 149 Dunes, i, 53, iii, 71, 74 Duplex Telegraphy, vii, 112, 114-17, 376 Dupuytren, Guillaume, x, 130 Duralumin, v, 228 Duryea, Charles E., v, 213 Dust, atmospheric, i, 52-65; atmospheric, elimination methods, ix, 269; body handling of, 223-4; deep sea deposits, iii, 54-5; effects on light, i, 165, 183; electric precipitation, vii, 216, 301-2, 347; in cloud formation, i, 91; in fog formation, viii, 304; in stratosphere, i, 20, 144; meteoric (see Meteoric Dust); methods of measuring, i, 61-3; physiological effects, i, 325; volcanic (see Volcanic Dust); wind-carrying of, i, 52-5, iii, 71, 73, 75, xiii, 344 Dust Count, Chicago standard, viii, 332 Dust-counter, i, 62, 371 Dust Whirlwinds, i, 60 Dusty Trades, i, 325 Dutch Language, relations of, xv, 160, 162 Dutchman's-pipe Vine, xiii, 131-3 Dyes, Dyeing, ancient Egyptian, xvi, 72-3, 74; antiquity of use, xiii, 210; chemistry of, viii, 258-60, xvi, 163; coal tar, viii, 253-4; importance of industry, 253-4; purple, sources of, xii, 68, 72 Dynamic Electricity, vii, 367 Dynamic Heating and Cooling, i, 90 Dynamic Meteorology, i, 123, 371 Dynamite, viii, 261; blasting with, v, 100; invention, 380 Dynamo-Electric Machines, defined, vii, 367 Dynamometer, iv, 102, vii, 367 Dynamos, iv, 306-8, vi, 49-56; discovery of principle, 22, 50; function, 72; Gramme's, 26; interchangeability with motors, discovery of, iv, 54; invention and development, xvi, 189; parts, vii, 367; pole pieces, 374; separate and self-excited, vi, 186-7; source of energy, 129; submarine, double uses, v, 199; voltage, on what dependent, vi, 131 (see also Generators) Dynamotors, vii, 136-7 Dyne, unit of force, iv, 69-70 Dyrenforth, Gen. Robert, i, 338 Dysentery, amoebic, x, 195, 199; from water pollution, viii, 318; in tropics, x, 251, xv, 50; overheating and, x, 307 Dyspepsia, from tight lacing, x, 309; mental effects, xi, 369-70 Dysprosium, atomic weight and symbol, viii, 383 Eads, Captain, Mississippi River jetties, xiv, 270 Eagles, xii, 260, 261; bald-headed, unions among, xv, 277 Earache, in children, ix, 104 Ear-mindedness, xi, 222 Ears, ix, 100-3, xi, 98-102; basilar membrane of, iv, 203; cartilage in, ix, 57; direction perception by, 117, xi, 167-9; disorders and care of, ix, 103-4; equal size of, 169-70; equilibrium organs in, 89-90; hearing by, iv, 203-4 (see Hearing); infections of, ix, 61-2, x, 219; limits of hearing power, iv, 204, ix, 99, 100; liquids of inner, iv, 203; movements of, in animals, ix, 82, 117; mutilations of, by savages, xv, 259; nerve connections, ix, 124, 142, 143 (fig.); origin, xi, 109; outer, in hearing, ix, 117; reddening of, in cold, 311; receptor organs, attunement, xi, 62; ringing in, iv, 203; sensitiveness of, 204, 211-12, 360; static sense organs in, xi, 126; temperature of, ix, 93 Ear Trumpet, iv, 239 Earth, agonic lines of, iv, 246; ancient ideas, xvi, 58; antiquity, iii, 21, 43, 201, 218, xiii, 306, 314, 322, xiv, 29, (see also Geological Ages); axis mutation, discovery, xvi, 124; center of universe, ii, 9 (see Geocentric Theory); centrifugal force of, iv, 75; changeableness of features, iii, 9-12, xiv, 3-4, 15-16, 28-30; changes in historic times, xv, 72; chemistry of, viii, 190-203; climate in past ages (see Climate); comets in relation to, ii, 279-80; crust (see Crust of Earth); density and specific gravity, iv, 98, 164, xiv, 11; diameter, ii, 64, 192, iii, 51; diameters, equatorial and polar, iv, 101, xiv, 9; electrification, i, 144, 145-6, iv, 269, 270, vii, 207, 209-10, 212-13; energy sources and losses, ix, 25-6; geological history, iii, 164-248, xv, 70-1, 72-6; gravity of, iv, 98-9, 101; heat from sun, amount of, 194; heat radiation and protection, 183-4; Hindu conception, ii, 36; interior, heat and condition, iii, 107-8, 120-1, 160, 162, iv, 164, xiv, 11-17, 312; internal heat utilized, v, 178-81, ix, 25, xiv, 15; internal waters, 151; land and water distribution, 20-7; life on, antiquity of, xv, 71; life on, beginnings, xiii, 298-304; life on, conditions necessary, ii, 242-5; life on, origin of, xii, 9-13; magnetic axis, iv, 250; magnetic field and lines of, 252-253; magnetic poles, 246, vi, 29-30; magnetism, ii, 178, 186, iv, 248-50, vi, 12, 29, 39-40; magnetism and internal iron, xiv, 11; magnetism in relation to aurora, i, 159-61; man's machining of, v, 251-67; mass of, iv, 98; motions (see Revolution, Rotation); origin, ancient ideas, ii, 366-7, xvi, 77, 78; origin, modern theories, ii, 373, iii, 158-63; rigidity, 107-8, xiv, 17; sciences of, xvi, 36; shadow in space, ii, 206; shape, 59, 69, 71, iv, 101, xiv, 9; shape, ancient ideas, ii, 10, 28, 30, 34-5; shrinking of, iii, 83-4, 108, 160, 162; size, ii, 162, 163; surface features, xiv, 9-11; temperature layers, 13-15; temperature ranges and control, ii, 243-4; temperature regulation by atmosphere, iv, 183-4; water circulation and supply, xiv, 134-5, 151; waters, past and future, ii, 244; waters within, iii, 109-10, 113-29; weight, ii, 68-9, 76, iv, 98, 164; wind and pressure belts, i, 128-9 Earth-Air-currents, i, 145, 371 Earth Movements, xiv, 32, 33-9; importance to human life, 341 Earthquakes, iii, 92-8, xiv, 330-43; faulting in, 39, 115, 128; lakes formed by, 203; submarine effects, 284; water table affected by, 136 Earthquake Waves, transmission of, xiv, 17, 332-3 Earthworms, xii, 51-3; power of distinguishing light, ix, 105 Earwigs, xii, 107 East Africa, ancient dinosaurs of, xii, 195; clan ceremonies in, xv, 363; development of, 136; glaciers in, xiv, 54; Great Rift Valley, 118-20, 121; lava fields and volcanoes, 103, 317 East Indies, animals of, xii, 145, 288, 352, 353, 359, 362, 370; beriberi in, x, 257; chocolate growing, xiii, 234; land and sea breezes, i, 131; nautilus of, xii, 75; nutmeg production, xiii, 261-2; Portuguese and Dutch in, xiv, 310; rattan palm of, 368; smallpox inoculation in, x, 207; spices from, xiii, 259; wild arum of, 153 East River, pipe-thawing under, vii, 338-9 Eastport, Maine, tide at, xiv, 293 Eating, effect of excitement during, xi, 374-5; kinaesthetic sensations in, 127; metabolism increased by, x, 271; obesity and, 273 Eccentric, of steam engine, v, 40-1 Echidnas, xii, 272-3 Echinoderms, iii, 259, 268-70, xii, 48-50 Echoes, iv, 237-9; aerial, i, 190, 193 Eclipses, ancient studies of, ii, 9, 32, 37; annular or ring, 214; elements of, 216; of Jupiter's moons, 263; of moon, 206-8; of sun, 209-18 (see also Solar Eclipses) Ecliptic, ii, 162, 350; plane of, 70, 163; poles of, 92; trepidation of, 38 Ecology, xiii, 354-7 Economic Botany, xiii, 208-66 Economic Geology, iii, 342-76, xvi, 172-4 Ectoderm, xii, 26 Ecuador, glaciers in, xiv, 54; yellow fever in, x, 160, 172-3 Eddies, wind, i, 292, 294, 371 Eddington, astronomer, ii, 17, 330, 341, 342, 347, 348-9, 354, 356, 382; quoted, 151, 320, 344, 384; "Stellar Movements," 319 Eddy Currents, vi, 192, vii, 365-6; in various machines, vi, 213, 225, 316 Edinburgh University, medical school, xvi, 179 Edison, carbon lamp, v, 381; carbon lamp filaments, xvi, 189; carbon microphone, v, 381; early dynamos, xvi, 188; electrical work, vi, 26; father of electric lighting, vi, 265; first incandescent lamp, xvi, 188; kinetoscope, v, 330; phonograph, 328, 381; quadruplex telegraph system, vii, 112; storage battery, vi, 149-51; vacuum tube discovery, vii, 276; Edison Closed Circuit Cell, vi, 137 Edison Electric Company, load factors, vi, 381-2; storage battery reserves, 382-3; tied with Interborough System (N. Y.), 384 Edison-Lelande Cell, vi, 139-40 Edison Storage Battery, vi, 130, 149-51 Education, association principle in, xi, 200-1, 203, 204; botanical, xvi, 22; environment in, xi, 249; grasping reflex, importance, 43; hygienic, x, 282-5; imitation in, xv, 66-7; importance of choices in, xi, 266-7; language and, xv, 145-6; modern, a summary of past, 145-6, 164; modern, beginnings, xvi, 111; necessity of, ix, 344, 352; progress in relation to, xv, 30-1, xvi, 47; reaction speeds, xi, 158, 159; sensation as, 68; Spencer on, x, 282, 284; waste of time in spelling, xv, 177; (see also Learning Processes) Eelgrass, fertilization, xiii, 150-1 Eels, xii, 162-3; vinegar and paste, 45 Effector Neurones, xi, 21, 22, 26; in embryo, 34 Efficiency, human, viii, 367, ix, 296, 306; climatic effects, x, 238-9, xiv, 357, xi, 369-82; temperature effects, i, 323-4 Efficiency, industrial, xi, 360, 362, 363 Efficiency of Machines, iv, 192, vi, 214, vii, 367; electric lamps, vi, 268; generators, 357, 379; heat engines, highest attainable, iv, 192; motors, vi, 228; power plants, 380-3; transformers, 317-18; various kinds of engines, v, 155, 161, 164, 170, 172 Egg Cells, production and development of, ix, 332-3, 335, 339, 343-4 Eggs, albuminuria from eating of, x, 345; amino acids in, 278; boiling of, viii, 368; boiling of, on mountains, iv, 170; calories in, ix, 299; composition and use, viii, 364; poisoning from, x, 212; vitamines in, viii, 369, ix, 33, x, 260, 261; white of, composition, ix, 176; white of, digestion of, 233 Egrets, xii, 244, 255 Egypt, antiquity of civilization in, xiv, 196, xv, 84; bats of, xii, 371; buffaloes in, 329; cats of, 355; geographical changes in, xiv, 33; lions of, xii, 359; locust plagues, 109; Nile inundation, xiv, 70-1; Nile valley fertility, 53, 71, 219; Pyramids (see Pyramids); rock weathering in, xiii, 23, xiv, 78-9; snowfall in Lower, i, 210; storks of, xii, 255; ziczac of, 263 Egypt (Ancient), agriculture, xiii, 210; astrology and astronomy, ii, 21, 23-6, xv, 269-70, xvi, 69, 70, 71; baboons in, xii, 380-1; brick-making in, xv, 267 (fig.); calendar, xvi, 70; civilization conditions, xv, 123, 127; crocodile in, xii, 199; dogs of, 346; donkeys in, 308; duck-hunting in, xv, 222; hairdressing in, 255 (fig.); history and civilization, xvi, 53, 65-75; humped cattle of, xii, 330; hunting dog of, 345; irrigation methods, iv, 27 (fig.), v, 18-19, 178, xv, 240; machines, v, 42; medical science, x, 11, 12, 31, xvi, 82; monuments and temples, ii, 24-6, 165; musical instruments, xv, 314, 317, 318, 319; papyrus, v, 289-90; peoples, xvi, 64-5; plague of blood, i, 358; poppy cultivation, xiii, 253; pottery-making in, xv, 249-50, 251 (fig.); sacred ibis of, xii, 255-6; sacred ichneumons of, 352; sailing vessels, v, 182; sciences, xvi, 54-75, 77, 96; scribes of, xv, 177 (fig.); slavery in, 378-9; spinning and weaving in, 243, 244, 245, 246 (figs.); stone-cutting in, 271 (fig.); stone-moving in, 270-1; sun-worship, ii, 20, 23, 24, 25-6; tops, v, 339; water clocks, 58-62; weapons of, xv, 211 (fig.); wheat in, xiii, 210; wheel in, v, 18-19 Egyptian Art, xv, 300-2; no perspective in, xi, 181 Egyptian Comet, ii, 134 Egyptians, ancient and modern, xvi, 65; ideas of cosmos, 77; ideas of insanity, x, 356; in Mediterranean group, xvi, 49; not seamen, xiv, 265, 306-7; scarabs of, xii, 123 Ehrlich, Paul, "atoxyl" of, x, 169; chemotherapy founded by, 381; immunity theory, 209, 211-12 Eiffel Tower, hail rods, i, 342, 344; horizontal rainbows seen from, 177 Einstein Theory, ii, 79-82, xvi, 196-8; æther constitution and, vii, 368; anticipations of, xvi, 85; Newtonian system and, iv, 18 Elands, xii, 327 Elasmosaurus, xii, 202 Elastic Cords, vibrations, iv, 216 Elasticity, iv, 35-6, 156-9; molecular, perfect, viii, 24; temperature effects on, iv, 198; vibration dependent on, 198, 213, 215, ix, 98, 100-1 Elation, in various sentiments, xi, 140, 150 Electrical Capacity, iv, 267-8 Electrical Conductors (see Conductors) Electrical Machinery, remote and automatic control, vi, 99-101; ratings, 192-4, 212, 317 Electrical Protective Devices, vii, 32-50 Electrical Terms, vii, 361-76 Electrical Units, iv, 284-5 Electric Arcs, direct currents best, vi, 332; extinguishing of, 102; Faraday's experiments, xvi, 189; heat of, iv, 312, vi, 348; heat and light, 280; on alternating circuits, vii, 208-9; used in nitrogen production, 323-4 (see Arc Process) Electric Batteries (cells), iv, 271-3, 295-300, vi, 58-62, 126-51, vii, 363; chemical action, viii, 167-9; defined, iv, 381, 382; depolarization, vii, 366; direct currents, vi, 154; direction of currents, 59; function, 72; invented by Volta, 18-19; local action, vii, 361; polarization of, iv, 296, 298, 383; primary and secondary defined, iv, 383; used in electrotherapy, vii, 241-4 (see also various kinds of batteries and cells) Electric Bell, iv, 290-2, vi, 99, 127, 138, 144, 306 Electric Breeze, vii, 238-9 Electric Cars, circuit-breakers in, vi, 101-2; construction, types, and operation, vii, 182-6; former and present feeling about, 75-6; growth and improvement, 180; movement on hills, vi, 232-3 (see Electric Traction) Electric Clocks, v, 74 Electric Currents, vi, 67-85; alternating and direct, 152-3 (see Alternating, Direct Currents); attracting and repulsion of, 20-1; cause of, iv, 265, 271, 273, vi, 46, 72; detection, 91; direction, 54-7, 59, 124; distribution (see Power Transmission); effects on human body, vii, 246-9; electron theory, vi, 123, 152, vii, 366; flow, vi, 46, 47, 67-9; follow least resistance, 96; Galvanic Faradic, and Franklinic, vii, 242, 243, 245; heat and light production by, iv, 310-12, vii, 337-8; induced, iv, 303-8, vi, 22 (see Induced Voltages); intensity, vii, 370; leakage, 371; magnetic effects of, iv, 273-9, 286-7, vi, 20-1, 88-91; measured by ammeters (see Ammeters); overloading lines, vi, 9, 72; production, 46, 72 (see also Dynamos, Electric Batteries, Thermal Couples); protection against overloading, vii, 34-50; selenium control valve, v, 332; surges, vii, 16-18; units and measurements, iv, 277-85, vi, 69-76, 82, 84-5; values, effective and maximum, 346-7; value in oscillating circuits, vii, 289-90; velocity, Watson's study, xvi, 123; wire capacity table, vii, 58 Electric Discharges, iv, 264-5, 267, 269, vii, 366; atmospheric, i, 157, 158-62; fog dispersal by, 94; in vacuums, iv, 317-18; nitrogen fixation by, viii, 73, 74, 346; rain-making by, i, 340; through gases, vii, 216, 301-2 Electric Eel, vi, 16, 64, xii, 160-1 Electric Energy, vii, 368; conversion into heat, 89, 303-5; due to difference of potential, iv, 263, 264, 265; equivalents, vii, 382; transmission (see Power Transmission); unit of, vi, 82; unit (joule), iv, 284, 294, 310, 312, vii, 370 Electric Fans, vii, 76-7, ix, 317 Electric Fishes, catfishes, xii, 161; electric eel, 160-1; torpedo fish, 149-50 Electric Furnace, iv, 312, vii, 302-12; history and uses, xvi, 189-91; invented by Acheson, vii, 301; operation and products, viii, 283-4 Electric Hammer, vi, 94 Electricity, iv, 256-321 vols. vi, vii; advantages in home and industry, vii, 51-2; animal (see Animal Electricity); atmospheric, i, 141-63, vii, 201-19, 362; attraction and repulsion law, iv, 256-8, 261, vi, 18, 122; basis of matter, iv, 23, vi, 107-8, 113, 118 (see Electron Theory); battleship applications, vii, 325-35; chemistry and, viii, 164 (see Electrochemistry); commercial units, iv, 312; conductors and nonconductors, 258-9, vi, 294-5 (see Conductors, Nonconductors); daily applications, xvi, 19, 20, 26-7, 30; defined, vii, 367; disadvantages in mines, v, 129; farm uses, vii, 220-34; flow, vi, 46, 67, 292-3; flow, direction of, iv, 265, vi, 56-7; frictional (see Frictional Electricity); history of development, iv, 52-5, vi, 9-26, xvi, 121-3, 188-92; home applications, vii, 73-90; identity of kinds, vi, 23; importance of understanding, 9-10, 64-6; late discovery and use, vii, 235; lightning and, vi, 10-11, 13-16; magnetism and, iv, 257, 276, vi, 12, 19-20, 21, 27-8, 86; "messenger" of physics, iv, 50; miscellaneous applications, vii, 336-59; name, origin of, iv, 256, vi, 12; not made, but moved, 46, 49, 72, 128; origin, latest views of, 105-25; physical effects of, x, 250, 254, xi, 117; popular applications of, iv, 10; positive and negative, i, 141, 142, iv, 258, 265, vi, 287; precise measurements, vii, 152; production of (see Electric Batteries, Generators, Power Plants); production by wind power, i, 38, v, 173; quantity unit, iv, 261, 277, 280, vii, 365, 374; science of power, xvi, 36-7; single-fluid theory, vi, 11, 288-93; static (see Static E.); transmission (see Power Transmission); uses and power, vi, 10; use in medicine (see Electro-therapeutics); wave lengths and frequency, vii, 260; wide familiarity with, 152-3; widespread interest in, vi, 330-1 (see further Electric Currents, Electric Power, Electromotive Force, etc) Electric Lamps, iv, 310, vi, 265-8; candlepower of, iv, 352, xvi, 189; detonation on breaking, vii, 211; Edison's inventions, xvi, 188, 189; energy requirements, iv, 311; light and heat, vi, 268; neon and argon fillers, i, 33; number used, vii, 51; short-circuiting by burning out, 35 Electric Lighting, vi, 264-83; advances in applications of, iv, 50-1, vi; direct and alternating current effects, 155-6; due to glowing of a solid, viii, 60; farm uses, vii, 231, 232, 233; fire hazard reduced by, vii, 51; history, xvi, 122-3, 188, 189; homes and interiors, vi, 275-8, vii, 68-72, 75; leading inventors, vi, 26, 265; meter units, iv, 312; outdoor, vi, 278-80, 283, vii, 339-4; small fraction of power used in, vi, 381; wide use and advantages, vii, 51, 52 Electric Locomotives, v, 212, vi, 161, 162, vii, 182; induction motors in, vi, 249; motors and currents, vii, 195-6, 200; power and efficiency, 193-4; regenerative brakes, 200 Electric Meters, vii, 151-79; for alternating currents, vi, 346-7; screening of, 32; units used in, iv, 312, vi, 82-3 Electric Power, costs, on what dependent, vi, 380-2; costs for farm work, vii, 224-6; extra charges for peak hours, vi, 301, vii, 177-8; measured in watts, iv, 310, 312, vi, 84-5; transmission (see Power Transmission); water power and, viii, 283 Electric Pumps, vii, 86-7; remote control, vi, 99-100 Electric Ranges, vii, 88-9; special rates for, 174 Electric Traction, vii, 180-200; block signals, 355; converters used, vi, 342; current used, 161-3; motors used, 231, 241 (see also Electrification of Railroads) Electric Waves, discovery of, iv, 55, 313 (see also Electromagnetic Waves) Electric Wiring (see Wires, Wiring) Electrification, iv, 256-62, vi, 11, 12, 13, 286; degree of, 17; methods of, iv, 265-7; of atmosphere, vii, 207, 212-13, 216-17; of earth and air, i, 144-6, 150 (see also Charged Bodies) Electrification of Railroads, v, 212, vi, 162, 249, vii, 181-2, 193-6; block signal system, vii, 359; brake system, 200; smoke relief by, i, 64; trolley and third rail systems, vii, 197-8 (see also Railroad Terminals) Electrochemical Analysis, viii, 294-5 Electrochemistry, vii, 299-324, viii, 164-9, 283-4, 312; organic, 266; use of direct current in, vi, 163; water power and, viii, 267 Electrodes, iv, 297, 317, 382, vi, 60, 129, 130-5, 367; graphite, vii, 308, 309 Electrolysis defined, iv, 382, vii, 367, viii, 375; industrial applications, vii, 312-24, viii, 164-7, 271, 272, 284; ionic hypothesis of, viii, 123-5; of organic compounds, 266; of water, 30-1 Electrolytes, iv, 382, vi, 23, 58, viii, 376; acids, bases, and salts called, 125; action of currents in, vi, 131-5, vii, 247; don'ts about, vi, 149; double-fluid, 137; in primary and secondary cells, 130 Electrolytic Cells, vii, 313, 367 Electrolytic Corrosion, vi, 65-6, vii, 189; alternating currents and, 305 Electrolytic Dissociation, viii, 123-4, xvi, 164-5 Electromagnetic Units, iv, 278-82 Electromagnetic Waves, form and lengths, vii, 371; length and frequency, 259, 260; transmitted by æther, vi, 119, 269 (see also Radio Waves) Electromagnetism, Electromagnets, iv, 286-94, vi, 30, 31, 86-104, vii, 367, 372; Einstein theory and, ii, 80-1 Electromotive Force, defined, iv, 271, 294, 382, vi, 46-9; dangers of uncontrolled, 64-5; generation, 49-66 (see Electric Batteries, Generators, Thermal Couples); induced and generated, vii, 370; measured in volts, iv, 280-1, 284, vi, 53-4, 57; phase relations, 167-9, 171-4, 242; self-induction, vii, 375; uses, vi, 56 (see also Voltage) Electromotive Force Waves, vi, 198-200, 208 Electromotive Series, viii, 127-9, 376 Electrons, vi, 113-15, vii, 367; beta rays, viii, 185, 186; from sun in upper air, i, 144, 146; in charged bodies, 142, 143; in sun, ii, 177-8; knowledge of, from radioactivity, viii, 307; motions in light, heat and electricity, vii, 371; nature, vi, 118, 120; negative electricity, viii, 187-8; original study, xvi, 193; size and weight, i, 141-2, viii, 187; speed in cathode rays, iv, 318 Electron Theory, iv, 321, vi, 26, 122-5, vii, 366, 367, 371, viii, 187-8; compared with Franklin's theory, vi, 288, 292; in various electrical actions, 133-4, 152, 153, 284, 288, 302, 338-9, 340; Larmor's proposal, xvi, 193 Electroplating, vii, 314-19, 374, viii, 164-6, 284 Electro-Refining, vii, 319-21, viii, 166-7, 284 Electrostatic Fields, iv, 261-2, vii, 368; intensity of, 370 Electrostatic Generators, vi, 298-301 Electrostatics, defined, iv, 259; importance of, 271 (see also Charges, Charged Bodies) Electro-Therapeutics, vii, 235-57, 368 Electrotyping, vii, 313-14 Elements, vi, 108-9, viii, 12, 16, 376, 383; atomic numbers, 183, 309; atomic weights (see Atomic Weights); classification, metals and nonmetals, 17-19, 126, 175-7; discoveries through Mendeléeff's tables, 180, 181, 182, xvi, 163; Greek idea of primary, 81, 83; in earth's crust, iii, 308, viii, 19, 190-1, 192, 194; in heavenly bodies, 302; in meteorites, ii, 292; in sea water, xiv, 295; in stars, ii, 115-18; in sun, 114, 128, 185, 211; isotopic and isobaric, viii, 189; made up of molecules, 26; number, 16, 183, 309; only things man cannot produce, vii, 310; origin in silicates, viii, 193; origin, remarks on, 84; periodic classification, 177-83; physical state and chemical properties, 297-8; potentials against hydrogen, vii, 383; properties dependent on atomic weights, xvi, 134; Prout's hypothesis of hydrogen basis, viii, 177; radicals or groups, 93; radioactive, 184-9; spectra of, ii, 113, viii, 302; symbols, 91, 383; tests of, 285-91; transmutation of, 188-9, xvi, 14-15; union types, viii, 20-1, 99-100; valency, vii, 384, viii, 93, 122 Elephants, xii, 301-4; breeding and domestication of, xv, 197; breeding rate, 20; evolution, iii, 300; fearlessness, xi, 136; formerly in Europe, xv, 76, 92; strength of, 18; trapping of, 225, 226 (fig.), 227; trypanosome in, x, 168 Elevation (geological), denudation increased by, xiv, 39, 40; effects on streams, 163, 164-70, 187-8; instances of, 33-4; of coasts, 253, 262; of ocean floor, xiv, 286 (see also Level Changes, Rejuvenation) Elevators, air cushioning, v, 134-5; first passenger, 380; hydraulic, 102-3; motors used, vi, 231, 234; power for fast and slow, 83, 85; sense of giddiness in, xi, 126-7 Elk, xii, 317, 318 Elm Trees, xiii, 194, 271-2 Embroideries, machine-made, v, 285-7 Embryo, development in man and animals, xv, 54, 55; development of human, ix, 343-4; development of nervous system in, xi, 34-6; flexed form of hand, 42-3; gill slits and notochord in, xii, 128; of mammals, 273; of marsupials, 274; past stages of race seen in, xv, 53-4; semiaquatic conditions, xi, 36 Embryo, of plants, xiii, 60 Embryological Development, x, 228 (see Embryo) Embryology, history, xvi, 107, 156 Emeralds, iii, 325; oriental, 327 Emergencies, body responses in, ix, 166-7, 171-2, 209, 220, 221, 293 Emerson, metaphor of, i, 187; on common mind, xi, 152; on narrowness of men, 376 Emery, iii, 327-8 Emmet, Thomas, x, 122, xvi, 186 Emotional Glycosuria, xi, 138 Emotions, xi, 129-42; associations determined by, 205-6; brain processes in, ix, 154; classes of, 153-4; combinations in sentiments, xi, 146-50; expression of, in men and animals, xv, 63-5, 152; fatigue and, xi, 274-6; hypnotic suggestion of, 317-18; in crowd psychology, 331-2; not localized in body, 62; pain and, 119, 120; physiological effects of, ix, 163-7, 171-2, 200, 209, 240-1, 348, x, 339, 353; primary varieties, xi, 55-6; suppression of, 140-2 (see also Suppressions) Empathy, xi, 172-3, 186; in advertising, 346-7; in salesmanship, 335 Empedocles, atomic theory, xvi, 87; malaria prevention by, x, 154; on matter, xvi, 83, 118 Empiric Doctrine (medicine), x, 24, 28 Emu, xii, 243, 249, xv, 194 Emulsions, colloidal state, viii, 314, 316, 356; defined, ix, 289 Encke's Comet, ii, 280; used to find Mercury's weight, 77 End Buds, of fishes, xii, 137 Endless Screw, v, 38, 37 (fig.) Endocarditis, x, 195, 332 Endoderm, xii, 26 Endoskeleton, xii, 127 Endothelial Cells, x, 197, 210 Energy, conservation of, iv, 40-1 (see Conservation of Energy); defined, 13-14, 37-9; equation of, 78; force contrasted with, 41; forms and transformations, 81-8; future sources of, v, 171-81; heat equivalent (see Mechanical Equivalent of Heat); kinetic and potential, iv, 79, 81-5, vii, 368; matter and, iv, 13-14; of plants and animals, viii, 334, 335, 336, 347, 349, 350 (see also Human Energy); physics as science of, iv, 12, 13-14, 50; power differentiated from, 80; radiant (see Radiant Energy); sources in nature, viii, 267-8, ix, 25-6, xiv, 31-2; sun as source of, v, 177, viii, 267, 334, 350, ix, 25-6, xiv, 32; transference and transformation of, iv, 37-41, 81-88, vi, 128-9; units of, iv, 79-80, ix, 295; unit equivalents table, vii, 382; universality of, iv, 13-14; work and, 37-40, 78-88; (see also Atomic E., Chemical E., Electrical E., Human E., Molecular E., Power) Engines, air and water cooled, v, 160-1; Clausius's principle, xvi, 135; heat, efficiency of, iv, 192; reciprocating and rotary, v, 148; two-cycle and four-cycle, 157-9; (see also Gas Engines, Gasoline Engines, Internal Combustion Engines, Steam Engines, etc.) Engines of Destruction, v, 359-75 England, Alpine Invasion, xvi, 49; beet cultivation in, xiii, 216; "Blackthorn winter," i, 363; chalk deposits, iii, 266; climate of, xiv, 345; coal supply, v, 172; coast destruction, iii, 56, xiv, 47, 301; coffee consumption, xiii, 232; early criminal justice in, xv, 372; first recorded eclipse, ii, 210; former connections with Europe, xiv, 271-3, xv, 76; grass snake of, xii, 217-18; insular position and results, xiv, 279-81, xv, 137; iron industry, v, 316; jute manufacture, xii, 243; lakes of, xiv, 200; landscape gardening, xiii, 267, 268; maritime supremacy, xiv, 262, 280-1, 307-8, 310; oak-hazel copses, xiii, 369-70; primitive inhabitants, xv, 83, 92-3; rainfall and verdure, xiv, 352; recent restrictions on power vehicles, v, 212-13; smallpox inoculation in, x, 207; sugar in, xiii, 215; surgery made a profession, x, 105; tea in, xiii, 228-9; tobacco introduction, 256; trees in, xiv, 375 English Alphabet, xv, 176 English Channel, first aeroplane flight, i, 43; historical importance, xiv, 279-80, xv, 137; impassable to quadrupeds, xiv, 273; tidal power system, v, 175-6; tides of, xiv, 294 English Language, changes in, xv, 156-7; double meanings of words, 158-9; foreign words in, 161; imitative words in, 153-4; origin of various words, 157, 161; relationships, 160, 162; spelling and pronunciation, 176-8 English People, characteristics, xiii, 172; insularity of, xiv, 280 English Sparrow, increase in U. S., xv, 21 Entada Scandens, xiii, 347-8 Enterokinase, x, 326 Entropy, iv, 193, xvi, 135 Environment, adaptation to (see Adaptation to Environment); change of, to relieve fatigue, x, 247; changes of, new species from, xv, 24-5; defined, x, 228; geographical, influence on civilization, xiv, 30-1, xv, 31, 122-39; habit and, xi, 249; health and disease factor, x, 237-44, 249-55, 303; heredity and, ix, 344, x, 228-30, xvi, 47; instincts as response to, xi, 49-53; man creature of, 57-8; man's conquest of, xv, 25-6; man's regulation to, x, 249-51; man the product and molder, of, xi, 33; mental effects of, x, 354; mind as response to, xi, 12, 24, 58; plant response to, xiii, 355-7; selection of, xi, 257; will and, 265 Envy, sentiment of, xi, 148 Enzymes, viii, 376, ix, 227, xiii, 83; in digestive processes, viii, 103, 226, 228, 357, 358, ix, 227, 228, 229-30, 235, 242; in infants, ix, 346; in tea, xiii, 230; in tobacco curing, 257 Eocene Period, animals of, xii, 306, 366; birds of, xv, 71 Eolithic Period, xv, 103-5 Epic Poetry, development of, xv, 321 Epicurus, atom theory, x, 26 Epicycles, ii, 35-6 Epidemics, Sydenham on, x, 74; tainted water and, xiv, 140 Epigenesis, xvi, 118 Epileptics, multiplication of, x, 235-6; primitive ideas of, xv, 350, 353 Epiphytes, xiii, 185, 362-3, 366; in tropical forests, xiv, 368 Epithelial Cells, x, 201, 202 Epsom Salts, viii, 149 Epyornis, eggs of, xii, 249 Equator, altitude of stratosphere at, i, 20; bulging at, ii, 69, 71; magnetic, xiv, 246; of wind system, xiv, 347; solar eclipses seen at, ii, 215; upper air temperatures, i, 20; weight of bodies at, ii, 69, iv, 75, 101; winds at, i, 127, xiv, 351 Equatorial Belt, winds and weather of, xiv, 348, 349 Equilibrium of Chemical Reactions, viii, 103-5, 190-1 Equilibrium of Forces, v, 183-4; science of, iv, 25 Equilibrium Sense, ix, 89-90, 156, x, 126, xi, 64, 126, 127; in infants, ix, 350 Equinoxes, defined, ii, 70-1; observed in Egypt, 25, 26, xv, 269-70; precession of (see Precession of Equinoxes) Eras, Geological, iii, 19-21, 378 Erasistratus, x, 23-4 Eratosthenes, ii, 10, 30 Erbium, symbol and atomic weight, viii, 383 Erg, energy unit, iv, 80; table of equivalents, vii, 382 Ericsson, air engine, v, 380; Monitor, 380; solar engine, ii, 169; steam fire engine, v, 378 Erie Canal, importance to New York, xiv, 267-8; through Mohawk Valley, 194 Erie, Lake, salt in, viii, 139; water constituents, 40; water supplies from, v, 260-1 Ermines, xii, 349-50 Eros (asteroid), ii, 191; distance, 132, 259 Erosion, iii, 28-9, 378; agents and processes, xiv, 39-79 (see also Glaciers, Ocean Waves, Streams, Wind); bad lands and canyons due to, iii, 139-40; base level, 30, 377 (see Base Level); by ground water, xiv, 141, xvi, 173; cycles (see Cycles of Erosion); earth movements and, xiv, 39, 40; final effect of, 80; illustration of recent, iii, 64 (Pl. 3); in deserts, 72; in Ice Age, 242; of faulted areas, xiv, 127; of folded areas, 94-6; of mountains, iii, 135, 139, 140-1, 188, 190-1, xiv, 233-4; present relief due to, iii, 32; rate of, xiv, 41; unequal operation of, 35 Erosion Surface (see Unconformity) Errors, fatigue and, xi, 274; of memory, 215-17; in space perceptions, 183-90 (see also Mistakes) Erysipelas, germ of, x, 195; immunity to, 207; puerperal fever and, 114 Eskers, iii, 70, 352 (Plate 20), xiv, 59-60 Eskimos, conditions of life, xv, 123-4; customs concerning dead, 338; ideas of future life, xv, 333, 335; kayaks of, 264 (fig.); language lacking in abstract words, 144; leadership among, 363; meat eating by, ix, 284, 309; polar bear catching by, xv, 224-5; reindeer uses, xii, 320; weapons of, xv, 209 (fig.), 210-12 Esophagus, functions and connections, ix, 230, 231; heartburn in, 232; operations of, xi, 37-9 Esparto Grass, v, 292 Espy, James P., i, 215, 345 Essential Oils, viii, 251-2, 336, 349 Esters, viii, 221, 245, 248, 376 Estuaries, formation of, iii, 37, xiv, 255, 256 Eta Argus, ii, 324 Eternity, real meaning, xi, 196 Ethane, derivatives, viii, 210 Ether, composition and properties, viii, 216-18, 376; density of, iv, 113; explosibility, viii, 62; refrigeration by, iv, 174; use as anesthetic, discovery of, x, 123-5, xvi, 185 Ether of Space (see Æther) Ether Structure, viii, 217, 224 Ethyl, defined, viii, 376; derivatives, 210 Ethyl Acetate, viii, 221 Etna, Mount, xiv, 100, 225, 316-17; flashing arcs, i, 194; water from eruption, iii, 107 Etruscans, vase decorations of, xv, 251 Eucalyptus Tree, xiii, 358; fertilization of, xii, 266-7; used in draining swamps, xiv, 379 Euclid, ii, 29, xvi, 81, 89, 95 Eudoxus, ii, 31, 300 Eugenics, x, 235-6, xvi, 157, 158 Euler, scientific work of, ii, 15, xvi, 125 Euphrates River, union with Tigris, xiv, 185 Europe, aeroplane routes, i, 44-5; after-summers, 362; Alpine invasions, xvi, 49; ancient animals, xii, 275, 310, 359; animals (carnivora), 336, 340, 348, 349, 350, 355, 356; animals, (herbivora), 307, 317, 318, 329, 330-1; aristocracies of, xv, 377; Asiatic invasions, xiv, 74-5, 362, xv, 138-9, xvi, 141; beet sugar production, xiii, 216; birds of, xii, 255, 261, 262, 263, 266, 268-9; Black Death in, x, 163-4; cave period in, xiv, 148-9; civilization in northern, 359; climate of, 346-7, 359; coast, western, 249; coffee introduction, xiii, 232; continental slope, xiv, 287; cretinism in, x, 350; Cro-Magnons in, xv, 99, 102, xvi, 50; dowry system in, xv, 285; drainage systems, xiv, 190; earthquake belt, 332; forests, 375-6, 377-8, 380-1; former connection with America, 290; geological history, iii, 180, 198, 216, 235-6; glacial topography, xiv, 3, 30, 43, 61-2, 200; gunpowder introduction, xvi, 101; hail prevention devices, i, 340-3; Ice Age in, iii, 62, 236-7, 239, 240, xv, 74, 75, 76, 102; languages of, 161, 162; map discrepancies, xiv, 10; mediæval astronomy in, ii, 39-41; meteorological statistics, i, 203; monkeys of, xii, 378; moor fires, i, 56; mussel-eating in, xii, 65; Nordic invasion, xvi, 50; nutmeg introduction, xiii, 261; paper introduction, v, 290; paper making, 292; plains of, xiv, 217; population increase, xv, 27; potato in, xiii, 218; primitive man types found in, xv, 88, 92-102; rainfall distribution, xiv, 352; rainfall stations, i, 79; revival of learning (see Renaissance); rice in, xiii, 214; rodents of, xii, 287, 288; snails of, 69, 70; snakes of, 218, 220, 231; snow removal in cities, i, 117; sugar introduction, xiii, 215; syphilis in, x, 60; tea introduced, xiii, 228; telegraph systems, vii, 108; tobacco introduced, xiii, 256; trees of, xiv, 363, 375-6; vegetables and fruits originating in, xiii, 222-7; volcanic belts, xiv, 316-17; weather observations, i, 217-18; windmills, 37 European Races, classification and history, xvi, 48-50 Europeans, comparative measurements of, xv, 57; hair of, 38; northern and southern, color of, 37 European Sleeping Sickness, x, 301-2 Europium, symbol and atomic weight, viii, 383 Eustachian Tube, ix, 101 (fig.), 102, xi, 101; adenoid effects on, x, 341-2; deafness from closing of, ix, 103-4; discovery, xvi, 82 Eutheria, xii, 271, 273-4, 281 Evaporation, body heat regulation by, i, 317, 318, ix, 316, 317; by trees, xiv, 377-8, 378-9, 379; (see also Transpiration); cooling by, iv, 174, viii, 69, ix, 316; electricity, caused by, vii, 212; ice made by, v, 349-50; measurement of, i, 88-9; of liquids, iv, 167; of terrestrial waters, xiv, 135; water table affected by, 136 Evaporimeter (see Aumometers) Everglades, Florida, draining of, v, 255 Evergreen Trees, deciduous, xiv, 370, 371; in landscape gardening, xiii, 269, 270, 271 (See also Conifers) Evesham Experiments, vii, 352 Evil Spirits, savage belief in, xv, 234, 304-5, 336, 339-40, 348, 352 Evolution, animals the main proof of, iii, 259, 260; Buffon on, xvi, 139-40; climatic, iii, 174; Darwinian theory, x, 135, 136, xvi, 149-52; Greek theories, 78-9, 139; human, xv, 26-31, xvi, 47; laws of, xv, 15-25, 381-2; laws and goal of, xiii, 325-36; Le Conte on, iii, 164; social, xv, 29-31, 382, 383-4; universality of, ii, 366, xv, 29, xvi, 152; Wolff's theory, xvi, 118 Exaggeration of Parts, iii, 277 Excavating, air pressures in, v, 120; through quicksands, 115-18, 123; under river-beds, 121-4; with water jets, 88 Excavating Machinery, v, 252-9; for swampy ground, 216 Excitement, blood changes in, ix, 293, xi, 137, 138; insomnia from, ix, 219; pain and, xi, 119; recovery period, 21 Exclusive Inheritance, x, 230-1 Exercise, effects, needs and rules, x, 303-6; effects on breathing, ix, 256, 258; effects on heart rate, 168-9, 207, 208-9, 261-2, x, 334; effect on lymphatics, ix, 223; effects on sweat glands, 169, 315-16; for constipation, 251, x, 317; heat produced by, 270, 306; obesity and, 273-4, 275; oxygen consumption in, ix, 261; psychological importance, xi, 339, 371-2; pulse rate after, x, 334; tuberculosis preventative, 292; violent, albuminuria from, 345 Exfoliation, iii, 24, 378 Exhaust, of engines, v, 164-5 Exhaust Fans, vii, 86 Exhaustion, kinetic theory, xi, 59-60; mental and physical, 135-6; nervous system in, 274; pain in, 119; unlike sleep, 286 Exoskeleton, xii, 127 Expansion, by heat, iv, 134-5, 138, 140, 145, 151, v, 71, viii, 25, 107; coefficient of, iv, 145; cooling by, i, 30, 90, iv, 188, 191-2, vii, 323, viii, 68; of fused quartz, vii, 311-12; of water and other substances on solidifying, iv, 149-51, viii, 38 Experience, ability to profit by, ix, 139-40, 152-3; accumulation and results, xi, 33; contradictions of, 11; learning and, viii, 269; learning by, in man and animals, xv, 66; psychology science of, xi, 10-11; sensations as, 68; subconscious storing of, 47; Sylvius's test of truth, x, 69 Explanations, slower than events, xi, 210 Exploration Drilling, v, 262-5 Exploratory Laparotomy, x, 147 Explosions, boiler (see Boiler Explosions); cause of detonations, vii, 211; chemical and physical processes, viii, 61-3; dust, i, 63; gunpowder, viii, 62, 145; hydrogen in air, 33, 36, 62; speed of sound in, i, 187 Explosives, viii, 63, 260-2; detonation, 262; history of development, xvi, 163; nitrogen compounds in, viii, 66, 71-2, 74, 75, 237, 253, xiv, 66; nitrogen waste in, viii, 345-6; sulphuric acid in, 80; weather making by, i, 335-9 Exposure (outcrop), iii, 381 Extemporaneous Speeches, xi, 245 Extension, perception of, xi, 166, 171-2, 183-9 Extensor Muscles, ix, 76-7, xi, 54, 166 Exteroceptive Senses, xi, 63 Extrusive Rocks, xiv, 105 Eye-and-ear Method (astronomy), xi, 155 Eyeglasses, benefits of, iv, 51 (see also Glasses) Eye-mindedness, xi, 222 Eye of the Storm, i, 136, 372 Eyes, vi, 270-3, ix, 109-11, xi, 83-97; abuse of, mental effects, 373-4; color, inheritance of, ix, 335-6; color in different races, xv, 37, xvi, 48, 49, 50; color perception by, ix, 116-17; color perception limits, iv, 360-1; comparable with camera, ix, 108; connection with brain, 124, 142; controlling nerves, xi, 30; depth perception by, ix, 120; diseases and defects, 112-14; distance of distinct vision, iv, 342, 343; distance perception by, ix, 118-19; double images, xi, 175-81; fatigue from, 279; fear effects, 132; fixation, how learned, 39-40; inflammation due to lack of vitamines, x, 260; in infants, ix, 350, 351, xi, 39, xv, 61; in sleep, xi, 282, 283, 286; muscles around, ix, 77; of various animal forms, xii, 67, 101-2, 138-9, 205-6, 209; origin, xi, 109; persistence of vision, iv, 346-7; position in attention, xi, 232; pupil size, iv, 343; receptor organs, xi, 30, 62; regulation to light, x, 254; sensibility to light waves, iv, 360; smooth muscles of, ix, 161-2; soul in, savage idea of, xv, 330-1; space perception by, xi, 169-70, 171-2, 173, 174-83, 186-90; winking and watering of, 19, 23, 63 (see also Sight, Vision) Eye Sockets, ix, 62 Eyestrain, ix, 113, 114, 239; Behan on, xi, 374 Eyra, xii, 364 Fabre, J. H., xvi, 143-4 Fabrics, making of, v, 268-88; manufacturing processes, viii, 256; Philippine fiber, xiii, 236, 239; warmth of different, ix, 311-12, x, 309 Fabry, Wilhelm, x, 78-9 Face, anthropological measurements, xv, 43-5; brain case and, 43, 62; in infants, ix, 345; pallor and flushing of, 161, 165, 166; brain power expressed in, xv, 39, 63-4; color in different lights, iv, 364-5; painting of, xv, 256 Facial Angle, xv, 44-5 Facial Expressions, xv, 63-4; dejection and, xi, 337, 339; man's trained control, 82, 350-1; smell and, 82; smiling, 357; taste and, 74, 75, 76; tone of voice and, xv, 144 Factor Differences, xiii, 330, 331-2 Factories, fatigue reduction, xi, 277; importance of conditions, 361-2; instruction of beginners, 363-5; lighting importance, 361; rest periods, 363; warm floors, importance of, ix, 320 (see also Industrial Plants, Industrial Psychology) Factory System, beginning of, x, 244; occupational diseases in, 245 Fahrenheit, Daniel Gabriel, iv, 135-6 Fahrenheit Thermometer, i, 73, viii, 27; compared with other scales, iv, 137, 141, viii, 27, 384; invention, i, 69; scale, how prepared, iv, 135-6, 137 Fainting, cause and relief, ix, 217; due to weakness, x, 89; low blood pressure in, 336 Fairmont, W. Va., deep well at, iii, 120, v, 265 Faith Healing, Barton on, x, 76; effectiveness, xi, 374 Falcons, xii, 260, 261; hunting with, xv, 223 Falkland Islands, groundsel of, xiii, 345 Falling Bodies, Galileo's studies of, iv, 19, 28, 97; laws of, 96-7, xvi, 31-3; velocity of, ii, 64, iv, 65; velocity on sun and earth, ii, 168 Falling Stars (see Meteors, Meteorites) Fall Line, xiv, 28, 214 Fallopius, x, 51, 53 Fallowing, viii, 341-2 Fall Winds, i, 132-3, 372 False Cirrus, i, 102, 104, 372 False Coral, xii, 47 Family, origin and evolution of the, xv, 273, 278-85, 360-1, 362 Fancy, pictures of, xi, 202 Fanning, benefits of, ix, 316-17 Farad, electric capacity unit, iv, 284, vii, 368 Faraday, chemical work, xvi, 160, 162, 163; discovery of anesthetics, 185; dynamo invention, 189; electrical work, vi, 16, 21, 22-3, 50; farad named after, iv, 284; metallurgical work, xvi, 174; on lines of force, iv, 252; on philosophers, x, 376; suggestion of fourth state of matter, xvi, 193 Faradic Currents, vii, 243, 248-9 Fargo, N. D., region, iii, 34 Farmers, ancient and recent methods, v, 239-40; motor machines, 214; past injustice and hardships, vii, 220-1; small, and machinery, v, 249-50 Farms, cost of horse work, vii, 224-6; electricity on, iv, 10, vii, 220-34; migration of boys from, 221; motor machines on, v, 214, 215-18 Far-sightedness, ix, 112-13, xi, 85 Fata Morgana, i, 172, 372 Fatigue, xi, 268-80; adrenalin effects, 137; cure for, x, 247-8; disorders and diseases due to, 246-9; from muscles, xi, 124; from posture, ix, 83, 84; habit and, xi, 253; insomnia from, 289; mental and physical, relations, x, 247, xi, 135-6; mental effects, 13; mental effects illustrated, xvi, 18; muscular, cause and effects, ix, 80-1; nervous, 137-8; no sense organs of, 91; physical effects of, x, 246-7; rest periods and, xi, 363; retardation of impulses in, 20; sleep in relation to, ix, 219; smooth muscles free from, 84-5; stimulation to change, xi, 338-9; suggestibility in, 307 Fatness, (obesity), x, 272-5; adipose tissues in, ix, 298; reduction of, 301-2 Fats, amount in daily diets, viii, 366-7, ix, 300-1; animal, viii, 246, 348, 349, 350, x, 260; animal, vitamines in, ix, 33; calories in, viii, 361, x, 269; composition, viii, 221, 245, 247, 335-6, 376; digestion and utilization, 356, 357, 359, ix, 242-3, 244-5, 289-90, 294, 298-9, x, 326, 330; extraction of, viii, 246; food value and requirements, 335, 336, 362, 363, ix, 33, 300-1, x, 256, 260-2, 268, 269, 271; identification of, viii, 310; indigestibleness of, ix, 286; in human body, viii, 348, 349; lipins, 350-1; liquid and solid, 232, 244, 247 (see also Oils); metabolism of, x, 270; molecular structure, viii, 217-18; not antigens, x, 205; preserving of, viii, 371; skin excretions, x, 310; soap effects on, viii, 141-2; soap made of, 141, 221, 246; tastelessness, 366; uses, 246-7; vegetable, 246, 335-6, 349, 350; vegetable, lack of vitamines in, x, 259, 260-1, 262 Fatty Acids viii, 220; butter percentage, 245, 364; candles made from, 247; in fats and oils, 221, 244, 245; soap made from, 221, 246 Faults, Faulting, iii, 86-92, 378, xiv, 37-8, 114-28; coasts formed by, 264; earthquakes and, iii, 87, 90, 93, 94-6, 97, 98, xiv, 39, 115, 128, 334-5, 339-41; greatest displacement, 39; hot springs in relation to, 143; lakes formed by, iii, 151, 152, 153; mountains formed by, 138-9, xiv, 226, 229, 230 Fault Scarps, iii, 378, xiv, 38; denudation of, 115-16; persistency of, 122, 123, 124 Fault Valleys, xiv, 127-8 Fear, cause and accompaniments of, ix, 153, 166, xi, 131-3, 136, 138; dominant human impulse, xv, 185; dreams from, xi, 293, 294, 299-300, 301-2; expression of, in animals, xv, 64; in various sentiments, xi, 146, 147, 148; pain deadened by, 120; subconscious processes and, 212-13, 214 Feathers, of birds, xii, 243-7 Feeble-mindedness, inheritance of, x, 234, 235-6; reflex action in, xi, 36 Feelings, brain processes in, ix, 154; classes of, 153-4; essentials of, xi, 25; expression of, xv, 143; motor response and, xi, 43 (see Consciousness, Emotions, Sensations) Feet, bones of, ix, 68-9, 70 (fig.); care of, x, 312; Chinese women's, xv, 260, 261 (fig.); cold or warmth felt in, ix, 320, 322; custom of covering, xv, 254; equal size of, ix, 170; mental impairment by troubles with, xi, 373; of ape and men, compared, iii, 301 (fig.), xv, 57, 60-1; of infants, 61; of Tertiary mammals, iii, 298, 299-300; proper shoeing, ix, 69-70, x, 306; relative lengths, xv, 57; soles of, nerve connections, ix, 132, 135; uses of, by men and monkeys, xv, 60-1; wetting of, and colds, x, 239, 306, 341 Feldspar, iii, 308, 328-9; chemical composition, viii, 90, 193; clay from, iii, 25, 27, 28, 373; disintegration, viii, 194; potash in, 201 Felt, making of, v, 289 Fer-de-lance, xii, 234 Ferdinand II of Tuscany, i, 69, 213 Fergusson, William, x, 130 Fermat, Pierre de, xvi, 105, 114, 119 Fermentation, alcoholic, viii, 248-9; of sewage, 328; of sugars, 225, 227; on what dependent, xiii, 66, 71; Pasteur's studies in, x, 137, 138-9, 141, 143 (see Alcoholic Fermentation) Ferments, viii, 357, 376; as catalyzers, 103 Ferns, xiii, 63-6; classification, iii, 251; cycad-like, xiii, 309; evolution, iii, 252, 254, 256, xiii, 303, 317; fossils, iii, 272 (Pl. 15), xiii, 324; in tropical forests, xiv, 368; mosses and, xiii, 69; number of species, 323; power of roots, 19; reproductive processes, 155-60 Ferrel's Law, i, 124-5 Ferrets, xii, 349 Ferric Compounds, viii, 161 Ferrite, viii, 160, 273 Ferrous Compounds, viii, 161; action of oxygen on, 194 Fertilization of Plants, xiii, 118-65; devices to insure, 48-53; of yucca plant, xvi, 152-3 (see also Cross Fertilization) Fertilizers, viii, 278-80, 342-6; ammonium, 147; garbage, 330, 343; natural, 327, 342-4; natural, in southern China, xiv, 73; nitrogen, i, 34, viii, 72, 74, 75, 137, 280, 345-6, xiv, 66; phosphate, viii, 89, 153, 279-80, 344-5, xiv, 67, 68; potassium, viii, 134, 146, 278-9, 344; potash, xiv, 67-8; primitive knowledge of, xv, 202 Festoon Clouds, i, 104, 372 Fetal Anlage, x, 120 Fetishes, xv, 348-9 Fevers, cause, temperature, and treatment, ix, 317-19; cooling of skin in, iv, 174; explanation of phenomena, x, 214; heart rate in, 334; improvement of treatment, xvi, 184-5; inanition in, x, 276; racial immunity and susceptibility to, xv, 50, 51; Sydenham's treatment of, x, 73; use of antipyretics in, 381 Fibers, cellulose, viii, 254-6; sources, uses, and kinds, xiii, 235-45 Fibrin, ix, 180 Fields, electrostatic and magnetic, vii, 368 (see Electrostatic Fields, Magnetic Fields) Field Strength or Intensity, vii, 368, 370 Figs, for constipation, ix, 251; origin, xiii, 225 Fig Trees, antiquity of species, xiii, 324-5; of Bahamas, 18; of Brazil, 365; of India (illus.), 16; of West Indies, 21 Filled Space, xi, 187 Filled Time, xi, 194 Filterable Viruses, x, 200 Final Common Path, xi, 22-3; in acquired tastes, 73; in association of ideas, 199; in attention, 230; preoccupation of, 119, 120, 121 Finches, coloring of, xii, 245-6 Fingal's Cave, jointed rocks in, xiv, 129 Fingers, bones of, ix, 67, 68, (fig.); curling of, in infants, ix, 349; flexed position, xi, 42-3; muscles for operating, ix, 76; of men and apes, xv, 60 Finland, coast of, xiv, 247, 259; lakes of, 200 Finland, Gulf of, salinity, xiv, 296 Fiords, (see Fjords) Fire, Civilization in relation to, ix, 308, 309, xv, 229; discovery of, v, 349; possibility of life in, ii, 251; production and sources, viii, 89, xv, 229-32; production by air compression, v, 128; production of, by friction, iv, 48-9; religious associations of, xv, 234 "Fire Animal," xii, 20 Firearms, v, 361-8, 379; ignition systems, viii, 145 Fire Balloons, v, 223 Fire Damp, iii, 354 Fire Engine, Ericsson's steam, v, 378; Hero's, xvi, 92-3 Fire Extinguishers, carbon tetrachloride in, v, 212; chemical and electric, vi, 101, 102 Fireflies, xii, 124; as ignis fatuus, i, 346; light of, vi, 268 Fire Hazard, electricity and, vii, 51-2, 223, 224; in rural districts, 231; reduced by lightning rods, i, 156 Fire Proof Type of Construction, vii, 55 Fire Pumps, v, 114 Fire Underwriters, Board of, vii, 53-4 Fires, caused by overloaded circuits, vii, 34; cause of "spalling" in, iii, 24; crowd psychology at, xi, 327-8; dust from, i, 56-7; extinguishing of, viii, 56-7; prairie, xiii, 374, 375; rain control by, i, 345; records in tree rings, xiii, 25 Fire-Weather Warnings, i, 240 Fireweed, seed dispersal, xiii, 343-4 Fir Trees, dominance in north, xiii, 350; forests of U. S., 367-8; in landscaping, 270-1 (see also Conifers) Fish, as food, ix, 24; calories in, 299; food value, viii, 362-3; vitamines in, x, 262 Fishes, Age of, iii, 20, 21, 283, xv, 71; anatomy and physiology of, xii, 132-6; bony, 151-3; breeding habits, 140-1; carelessness of offspring, xv, 275; cartilage skeletons of lowest, ix, 58; catching of, by savages, xv, 227-8; catching of, with cormorants, 223-4; classification, iii, 260, xii, 142; deep sea (see Deep Sea); eggs, 140-1, 155, xv, 21, xvi, 116; evolution, iii, 282-5; food of, ix, 24; intelligence in, xii, 139-40; leeches and, 56; migrations in relation to plankton, xvi, 147-8; modern, xii, 154-66; number of species, xvi, 146-7; of oceanic islands, xiv, 278; oxygen supply of, viii, 35, ix, 182; rate of increase in, xv, 20; regeneration in, xii, 170; reproduction in, 140-1; sense organs, 137-9; "showers," of, i, 355; temperature variations, 317; temperature variations, effects, ix, 78 Fish-eye Views, iv, 374 Fishhawks, xii, 260 Fish Patrol, Aerial, i, 48 Fission, xii, 26 Fissures, defined, iii, 378; ore deposits in, viii, 199 Fissure Springs, xiv, 138, 152 Fitch, John, steamboat, v, 189 FitzRoy, Admiral Robert, i, 224-5, 282, 363 Fiume, importance to Jugoslavs, xiv, 268, 306 Fixation (sight), how we learn, xi, 39-40 Fixed Stars, ancient idea of, ii, 350; motions of, 46, 86-7, 121-2, 304-5 (see Stars) Fjords, Fjord Coasts, xiv, 258-62; Norwegian, formation of, iii, 79; Norwegian, frost smoke, i, 95 Flagellate Cells, xii, 30-1 Flame, viii, 57-61; colors as metal tests, 133, 134, 144, 289, 301; heat production by, iv, 138, 144 Flamingos, xii, 256 Flammarion, books on Mars, ii, 238; on curious showers, i, 355; on lightning pranks, 153-4 Flamsteed, astronomer, xvi, 124; star numbering, ii, 302-3 Flannel, heat conductivity, iv, 179 Flannelette, x, 308 Flashboards, vii, 40 Flash Boiler, v, 213 Flashes, electric, vi, 91; extinguished by electromagnets, 102 Flashing Arcs, i, 194, 372 Flatfish, eyes of, xii, 138 Flatulence, sleeplessness from, ix, 219 Flatworms, xii, 18, 44-5 Flavors, ix, 95, 97; chemistry of, viii, 251-2; food value, 366, ix, 98, 240, 242; in plants, viii, 349; perception of, ix, 97-8 Flax, retting of, xiii, 243; spinning of, in ancient Egypt, xv, 243, 244 (fig.) Flax Plant, products and origin, xiii, 235, 244, xiv, 382 Flesh-eating Animals, as food, ix, 24; bile color in, 275; intestine length in, 246; protein surplus in, 284-5 Flexner, medical work of, x, 200, 218, 302 Flexor Muscles, ix, 76-7; strength, xi, 41, 43; withdrawing reactions by, 54 Flies, xii, 120; appearance in Jurassic, 104; buzzing of, 103; claws of, 102-3; evolution and varieties, 104-6; plant fertilizers, xiii, 131-3; typhoid fever spread by, x, 287, 288; wings of, xii, 103 Flight, bodily preparations for, ix, 166; instinct of, xi, 55, 132, 136 Flint, iii, 13, 337; fire production by, iv, 48; flaking of, xv, 103, 104, 107 (fig.), 109 Flint and Steel, xv, 232 Flint Implements, ancient, xv, 79, 81, 82, 87, 104, 105, 109 Flintlock, viii, 145, xv, 217, 218 (fig.) Floating Bodies, v, 95, 195-6; laws of, iv, 103-4, 107 Flood Lighting, vi, 283 Flood Plains, iii, 379, xiv, 53; alluvial soils of, 70, 71; embankments and slopes, 161-2; illustration, iii, 80, (Pl. 4); in old and new areas, 33, 34; plant societies of, xiv, 372 Floods, power of, iii, 31; rainfall and, i, 110-11 Flood Warnings, i, 240 Floors, warm, importance of, ix, 320 Flora, defined, xiv, 363 Florida, alligators of, xii, 197; coal forming conditions, iii, 199; coasts of, xiv, 251; co-, xii, 40, 42; crocodiles of, 198; frosts in, xiv, 370; serpula quina rock, viii, 152; coral reefs, tubes, xii, 55; shad fishing in, 155; snakes of, 226, 236; tarpon of, 154; wolves of, 341; youthful topography and drainage system, xiv, 157-8, 199-200, 201 Florissant, Colorado, insect remains at, iii, 279-80 Flour, calories in, ix, 299; Graham, ix, 35; vitamines in various kinds of, x, 262, 267 Flourens, Dr., x, 126, xvi, 185 Flowering Plants, beginnings and development, iii, 20, 252, 255, 256-7, xiii, 318-19; classification, 60-1, 173-81; classification place, iii, 251; culmination of plant life, xiii, 73-4; description of parts, 15-62; families and relationships, 168-207; in relation to animal life, iii, 257; none in earliest ages, xiii, 303; number of species, 168, 319, 323; origin of present, 323-5; reproductive methods, 117-54, 167 Flowerless Plants, iii, 251, xiii, 13, 14, 43; evolution, iii, 252, 253; ferns, xiii, 63-6; nonvascular, 66-73; numbers, 168; reproduction, 62-4, 154-65 (see also Cryptogams) Flowers, annuals and perennials, (tables), xiii, 289-97; coloring and fragrance, 124-5; colors in various shrubs, (table), 274-88; family groups determined by, 184; fertilization devices, 48-51, 117, 123-48; fertilization the climax of life, 152; highly cultivated, 51; largest, 363-4; love in, 115; matings of, remarks, 116-17; male and female, 46-7; motion pictures of growth of, iv, 348; of monocotyledons and dicotyledons, xiii, 176, 178, 189-90; parts of, 43-6; purpose, 46, 52-3, 61; various forms and colors, 47-53, 181-207 Flu, (influenza), x, 294-5 Fluctuating Variations, xiii, 328 Flue Gases, electric clearing, vii, 216, 343 Fluids, distinguished by pressure and diffusibility, iv, 22-3; elasticity of, 158; osmosis, xiii, 90-1 (see Osmosis); pressure of, iv, 116-19; pressure on moving inclined planes, i, 287-8; principles applicable to, iv, 126 (see Gases, Liquids) Flukes, sea, xii, 44 Fluorescence, iv, 379-80; produced by X-rays, 318, 320 Fluorescent Screen, iv, 320, vii, 254-5, viii, 184 Fluorine, a halogen, viii, 18, 84, 85, 87; atomic weight and symbol, 383; in apatite, 193; in tissues, 354 Fluorite, iii, 329-30 Fluoroscope, iv, 320 Flushing, of skin, ix, 161, 162, 163, 215 Flute, development of, xv, 316, 317 (fig.); Egyptian, 314 (fig.) Fluxing, of ores, viii, 270 Fly-Catcher (plant), xiii, 40-1 Flying Dragons, xii, 206 Flying Fish, order of, xii, 163; wings of, 134 Flying Mice, xii, 278 Flying Reptiles, iii, 293-4, 320 (Pl. 18), xii, 202, 203 (fig.) Foci of Infection, x, 198-9, 218-26 Focus, defined, iv, 335; of cameras, ix, 108-9; of eye, 110-11; of lenses, iv, 338; real and virtual, 335 Foehn Sickness, i, 328 Foehn Wall, i, 105, 372 Foehn Winds, i, 133, 372 Fog, i, 93-7, 372; aviation effects, 300-2; costs and dispersion, 94, 302; dust nuclei, x, 62, viii, 304; dry (see Dry Fog); light diffraction by, i, 183, 185; rime formed from, 121-2; sound transmission by, 190 Fog Bows, i, 176, 372 Fog Drip, i, 351, 353, 372 Fog Hiccups, i, 195 Fog Signals, audibility, i, 189-91; sirens, iv, 205 Folded Mountains, iii, 131-8, 190-1, xiv, 36-7, 226-34; ridges in, 93-4, 95-6 Folding of Rocks, iii, 84-6, 349 (fig.), 379, xiv, 36; theories of process, 231-2; topography made by, 38, 93-9 Food, Foods, adulteration of, viii, 370-1; amount consumed, 366-7; artificially prepared, x, 257, 267-8; benzenes and paraffins as, viii, 234; calories in various, 361, ix, 299, x, 269; calories, valuation in, iv, 48; chemistry of, viii, 348-72; children's, x, 314-15; cold storage of, iv, 187, 8; constituents all in air and water, i, 25; cooking of, viii, 367-9, x, 263, 266 (see Cooking); deficiency of, diseases from, x, 255-69, 276; digestion and utilization, viii, 356-9, ix, 226-52, 277-304, x, 268-71, 319-20; fat-producing, x, 273; infants', ix, 346-7; kinds needed during exertion, xi, 278; methods of obtaining, importance of, xv, 186-7; nitrogen importance, viii, 66, 229; of animals and plants, 349, 350, xii, 15; procuring of, by animals, ix, 18-20 (see also Chemotaxis); requirements, viii, 362-7, 369-70, x, 255-68, 278-9; selection of, viii, 369, ix, 300-1; sources of, 24-30; storing of, by animals, xii, 292-3; taste and smell of, ix, 94-5, 97-8, 240, 241-2; use of, for energy development, 15-16, 24, 36-40, 289-301; use of, for growth, 31-4, 38-9, 286-9; use of, for tissue repair, 34-6, 278-84 (see also Diet, Nutrition) Food-poisoning, indigestion from, ix, 239 Food Plants, xiii, 209-27 Food Preserving, viii, 371-2; chilling and refrigeration, v, 346, 353; X-ray sterilizing, vii, 257 Food Supply, its making by plants, xiii, 77-84, 95, 96; of tropics, 359 "Fool's Gold," iii, 335 Foot Candle, iv, 352, vii, 368 Foot-pound, iv, 79, vi, 82; erg and calorie equivalents, vii, 382; equivalent in watt-hours, iv, 312; heat equivalent, v, 350-1 Foot-pound-second System, iv, 46 (see British System) Foot-poundal, unit of work, iv, 79 Foraminifers, iii, 54, 259, 261, 266; in pelagic plankton, xii, 17-18 Force (mechanics), iv, 33-4, 41; centrifugal and centripetal, 71-5; defined, v, 182-3; law of, in machines, iv, 90, 92; Leibnitz's theory, xvi, 117; magnetic, vii, 369; measurement and units of, iv, 46, 58, 63-5, 69-70; momentum and, 66-7; motion and, 56-69, 71-2, 78; Newton's and Huygens' studies of, 11; primary forms of, 25; static and kinetic measures of, 33; work in relation to, 37-8, 78-9 Force Pump, v, 113-14 Forces, composition and resolution of, iv, 75-7; parallel, 99; parallelogram of, v, 184-6 Forecasts, i, 224 (see Weather Forecasts, Crop Forecasts) Foreign Languages, advantages of learning, xv, 146; jabbering sound, xi, 103; difficulty of learning, 201 Foreign Plants, importation forbidden, xiii, 272, 289; introduction aided by phenology, i, 254 Foreign Trade, meteorology in, i, 268-9 Forest Fires, aeroplane lookouts, i, 48-9; dust from, 56-7; losses by, xiii, 371-2; number and losses, i, 48-9; rain and, 333-4; records in tree rings, xiii, 25 Forests, ancient, iii, 252, 253-4, xiii, 10, 307-10, 312, 313; branching of trees in, 86; burial by sand dunes, iii, 74; climate affected by, xiv, 379; climax, xiii, 370; conservation of, xiv, 238-9, 382-3 (see also Conservation); earthquakes in, 333; European, 238-9; grasslands and, xiii, 348-9, 368 (illus), 374-5, xiv, 380-1; importance to industry, vi, 366; leaving of trees in, xiii, 86-7; migration of, xiv, 375-6; mountain, 239-9; northern limit, 375; park, 374; products, 382-3; rainfall and, xiii, 372, xiv, 377-8; soil protection by, 42, 379; squirrel planting of, xiii, 340; temperate, 366-73, 272 (illus), xiv, 370-1; trees in American and European, 363, 375-6; tropical, xiii, 358-66, xiv, 366-70; types of, xiii, 357-8; United States, xiv, 239, 372-4; United States national, xiii, 371-2; water supply and, 371-2, 9, xiv, 239 Forgetting, process of, xi, 209; rate of, 216 Forked Lightning, vii, 205, 206-11; sinuous character, i, 146 Form, athletic, ix, 159 Formaldehyde, viii, 219, 333, 335, 372 Formic Acid, viii, 220 Formosa, rice paper tree of, xiii, 214; continental island, xiv, 274 Form-wound Coils, vi, 202, 223, 245 Fortin's Barometer, iv, 119-20 Fossane, xii, 353 Fossil Botany, xvi, 167 Fossil Record, extent, iii, 13-14; imperfectness, xiii, 302-3, 306-7, 323-4, 325; of various geological strata, iii, 165, 174, 179, 180, 263-5, 268 Fossils, defined, iii, 13, 379; formation, 15-17; formation of plant, xiii, 301-2; former views of, iii, 14-15; geological strata determined by, 15, 18-19, xvi, 126, 169; of earliest animals, iii, 261-2, 263, 265-6; of earliest birds, xii, 239-43; of herbs and woody plants, xiii, 319, 324; of sharks' teeth, xii, 142; of water plants, xiii, 303; of worms, iii, 270; oldest known, 250; some remarkable, 286-8, 291, 292, 295, xiii, 306, 347 Four-Cycle Engines, v, 159, vii, 123-4 Fourdrinier Paper Machine, v, 291, 295-8, 377 Four o'Clock (flower), colors in crosses, ix, 334, 336 Foussa, xii, 353, 354 Fowls, white meat of, xii, 247 Foxes, xii, 342-4; excavators, xv, 206; storing of food by, xii, 292 Fox Fire, i, 346 Fractional Distillation, i, 32, iv, 168 Fracto-Cumulus, i, 102 Fracto-Nimbus Clouds, i, 101 Fracto-Stratus Clouds, i, 102 Fractures, Pott's, x, 92; X-ray locating of, vii, 254, 255, x, 185 France, aluminum production, iii, 369; ancient fossils found in, 252, 263, xiii, 319; botanical education, xvi, 22; chalk deposits, iii, 266; coasts, xiv, 46, 47, 257; Cro-Magnons in, xv, 102; early civilization of, xiv, 359; first balloons, v, 219-21; forestry in, xiv, 239, 382; hail devices, i, 341, 342-3, 343-4; harbors of north coast, xiv, 270-1; invasions of, course taken, 92; mistral winds, i, 133; Northmen in, xiv, 261; oyster culture in, xii, 62; Paleolithic remains in, iii, 304-5; rainfall of northern, i, 338; river changes in, xiv, 184; standard gun-manufacturing, v, 49; tidal power plants, 176-7; surgery made a profession, x, 104-5; topography in World War, xiv, 86 (map), 88-93; tuberculosis campaign in, x, 175-6 Franco, Peter, x, 57, xvi, 108 Franklin, Benjamin, cold season theory, i, 58-9; climatic changes paper, 200-1; electrical work, vi, 10-11, 13-16, xvi, 121, 188-9; lightning experiments, i, 141, iv, 269-70, vi, 11, 14-16, vii, 204-5, xvi, 121; lightning rods, vii, 218-19; medical work of, x, 104; meteorological work, xvi, 177; on "magnetic sleep," 185; single-fluid theory, vi, 11, 288 Franklinic Currents, vii, 245 Fraunhofer Lines, ii, 112, iv, 362, viii, 302 Frazer, Sir J. G., i, 334 Frederick Barbarossa, medical interest of, x, 38 Freeze, defined, i, 372 Freezing, expansion of water on, iv, 149-51; heat production by, 161 Freezing Mixtures, iv, 175; known to ancients, v, 349 Freezing Point, in various thermometers, i, 73, iv, 136, 137, 141, viii, 27; of solutions, 299-301; of various substances, iv, 173; pressure effects on, 163-6 Freiberg, School of Mines, xvi, 126, 127 Freight Engines, modern, v, 210 French, in Alpine group, xvi, 49; in America, xiv, 31, 191-2, 242, 310, 311 French Language, descent from Latin, xv, 160, 162 French Revolution, causes and results, xvi, 128; crowds of, xi, 326; metric measures adopted in, iv, 136; results on cultural advance, x, 107 Frende, Gabriel, i, 244 Fresnel, light studies, xvi, 137 Freud, Sigmund, on dreams, x, 364; on hysteria, 361; psychoanalysis of, 363 Freudian School, work of, xi, 142 Friction, iv, 92-4, v, 203-7; fire obtained by, viii, 89; heat production by, iv, 48, 138; in tubes, ix, 215 Frictional Electricity, iv, 257-8, 260, vi, 11, 12, 13, 286-7; discovery, xvi, 122; electron theory, vi, 122-3; identical with other kinds, 23; single fluid theory, 288 Frictional Machines, iv, 265, vii, 236, 245 Friction Matches, iv, 49, 138, viii, 88 Fried Foods, ix, 286 Frigate bird, xii, 253-4 Fright, physiological effects of, ix, 161, 165, 221, 240-1 Fringed Gentian, a biennial, xiii, 16; corolla of, 44 (fig.) Fringing Reefs, xii, 41, xiv, 263 Frisian Islands, coast destruction in, xiv, 46 Frogs, iii, 285, xii, 169, 174-6, 177-81; evolution of, 167; heart of, ix, 84; regeneration in, xii, 170; sense organs in, 169, 174; "showers" of, i, 355; temperature effects on, ix, 78-9, 306 Frostbite, x, 252 Frosts, i, 257-60, 373; insurance, 270; rock weathering by, iii, 24, xiv, 62, 75-7, 233 Frost Smoke, i, 95, 373 Fructose, viii, 226 Fruit, defined, xiii, 53-4; development, 54-5; dry and fleshy, 54-5; family groups determined by, 184; flavors due to esters, 221; food value, 365, ix, 34, 300, x, 262, 266, 268, 273, 317; in grasses and sedges, xiii, 179, 182; purposes of, 61; seed dispersal, 55-9 (see also Seed Dispersal); sugar storage in, ix, 27-8 Fruit Trees, as index plants, i, 255-6; frost danger points, 258 Fuels, future motor, viii, 209; heat measurement, 360-1; our waste of, v, 172; power from oxidation of, ix, 15-16, 24 Fuel Value, viii, 360-1 Fuji-san, Japan, xiv, 100, 320 Fujiyama, Japan, as observatory site, ii, 145, 149; shadow in sky, i, 170 Fulgurites, i, 153, 373 Fuller Cells, vi, 137, 142-3 Fully, Lake, water drop, v, 81 Fulminating Mercury, viii, 262 Fulton, Robert, steamboat, v, 192, 377; steam war vessel, 378; submarine, 197-8 Functional Metabolism, ix, 39; control of, 39-40, 77-8, 170; daily amount in calories, 297; food requirements dependent on, 295; heat production by, 307; no tissue wastage by, 282-3; of glands, 159; of muscle cells, 74, 77-9; of nerve cells, 122-3; of posture, 84; of vital processes, 295-6 Fundamental Tones, iv, 213; of bells, 222; of organ pipes, 228-30; of vibrating strings and rods, 223-4 Fundy, Bay of, tides, v, 175, xiv, 293 Fungi, xiii, 70-1; in coal formation, 312; luminous, i, 346; reproductive processes, xiii, 164; in rotten plants, 99; species, 323; spores in atmosphere, i, 61 Fungicides, viii, 77, 333 Funk, Casimer, x, 259 Furs, source of costly, xii, 346-51; warmth of, iv, 178, ix, 311, x, 309 Furrows, of continental shelves, xiv, 287 Fusel Oil, viii, 214 Fuses, purpose and construction, vii, 34-7, 369; inverse time features, 37, 39 Fusibility, of minerals, viii, 202, 384 Fusion, latent heat of, iv, 152, 160, 161; table, 162 Fusions, of odors, xi, 81; of tastes, 73; of tones, 106; of touch, 111 Future, a habit of thought, xi, 192; predictions of, xv, 354, 355 Future Life, primitive conceptions of, xv, 332-6, 339, 340, 345, 358 Gadflies, xii, 120 Gadolinium, symbol and atomic weight, viii, 383 Gailey, James A., v, 383 Galactose, viii, 226 Galagos, xii, 375 Galapagos Islands, xiv, 276; turtles of, xii, 187, 192 Galaxy, ii, 350-6; as basis of star distribution, 350, 353, 354, 364-5; globular clusters and the, 339, 343; nebulæ and the, 363, 364-5; solar system and, 353-4; spectra of stars, 116; star streams and, 346; studies at Mt. Wilson, 158-9, 160; type of stars, 122; variable stars and, 327, 328, 330, 332 Galen, x, 28-31; anatomical ideas disputed by Vesalius, 51, 52, 53; arterial bleeding unknown to, 39; authority in Middle Ages, 32, 34, 36, 37, 39, 41, 43, 51, 52; classification of minds, xi, 152-3, 155; classifying tendency of, x, 83; Locke, on, 75; medical works, xvi, 98; on circulation of blood, x, 22, 62-3, 65-6; on convulsions, fainting, etc., 89; on occupational diseases, 244; Paracelsus on, 47, 48; revival of writings, 44, 45 Galena, iii, 330, 362, 363, 368 Galilee, Sea of, formation, iii, 156; level, xiv, 121 Galileo, astronomical work, ii, 14, 53-6, iv, 27-8; astronomical and other work, xvi, 103; discoveries, ii, 83, 94, 96, 262; falling bodies demonstration at Pisa, iv, 28, 97, 101; medical advances due to, x, 67; motion studies of, iv, 19, 28, 35, 61; on Galaxy, ii, 351; on Gilbert, xvi, 109; on laws of motion, ii, 63; on Mars, 227; pendulum discovery, v, 63-5; pendulum clocks suggested, 65; studies of nebulæ, ii, 357; telescopes, 12, 94, 95; thermometer invention, i, 68, 69, x, 71; Torricelli pupil of, iv, 114 Gall Bladder, inflammations of, x, 220, 224 Galley Worms, xii, 88-9 Gallium, discovery of, viii, 180; symbol and atomic weight, 383 Gallon, cubic inches in, iv, 46 Galls, on plants, xii, 125; on roots, xiii, 98 Gall Stones, ix, 276 Galton, Sir Francis, eugenic work, xvi, 157; on ancestral heredity, x, 231; on fatigue, xi, 275; on sun's corona, ii, 222; statistical methods, xvi, 153 Galvani, electrical work, vi, 16-17; electrical work, xvi, 122, 189 Galvanic Batteries, vii, 369 Galvanic Cells, vii, 236, 241-2 Galvanic Currents, vii, 242, 244, 248 Galvanism, discovery, xvi, 122 Galvanized Iron, vii, 318-19, viii, 155-6, 273 Galvanometers, iv, 279, vii, 179, 369; invention, vi, 23, 24 Galveston, harbor of, xiv, 269; hurricanes, i, 136; hurricane of 1900 and rebuilding, xiv, 302-3 Game Birds, xii, 261-3 Games, athletic, advantages from, x, 304 Gamma Rays, i, 143, viii, 185 Gamopetalae, xiii, 47, 190, 201-5 Ganges River, crocodiles of, xii, 201; delta, iii, 32, xiv, 53; erosion by, iii, 31; furrow of, xiv, 287 Ganglia, of nerves, xi, 26 Gangue Minerals, viii, 199; handling of, 269, 270 Gannets, xii, 253 Ganoids, iii, 283 (fig.), 284, xii, 152-3 Ganoid Scales, xii, 134 Garbage, as fertilizer, xv, 280, 343, 344; disposal of, 330, 346 Garda, Lake, formation, iii, 146; in rift valley, xiv, 123 Garden Plants, xiii, 267-97; origin of, xiv, 382 Garfield, James A., speech of, xi, 323 Garnet Group, iii, 330 Gar Pikes, xii, 134, 152, 153 Garua, Peruvian fog, i, 95, 373 Gas Carbon, electrical conductivity, iv, 283 Gas Constant, iv, 142 Gas Engines, v, 155-6, 381; efficiency, on what dependent, iv, 192; ignition, vii, 369; in submarines, vi, 239; operation in automobile, vii, 123-33; starting of, vi, 235 Gases, adiabatic change in, iv, 158-9; atmospheric, i, 9-16; Boyle's Law, iv, 125-6, 133, 143; Boyle's and Mariotte's researches, xvi, 110; buoyant effect, iv, 30; Charles's Law, 140; chemical properties, viii, 297-8; combinations, Gay-Lussac's studies, xvi, 133; compressibility variations, iv, 143; condition at absolute zero, 142-3; conversion of liquids into, 152-3, 173-4; cooling by expansion, i, 30, 90; critical temperature, 29, iv, 171-3; diffusibility of, iv, 23, 131, viii, 22-3, 23, 108; distinguished by pressure and diffusibility, iv, 22-3; elasticity of, 158-9, 198; electric discharges through, 54-5, vii, 216, 301-2; electrolytic separation, 321-4; electrical conductivity of, iv, 259; expansion by heat, 135, 151; expansion coefficient, 145; flame due to burning, viii, 57; gram-molecular volume, viii, 109; heat absorption, 309; heat convection in, iv, 178; heat effects on, 139-40; heat from compression, i, 90, v, 351; heat non-conductivity, iv, 177, 178; ignition, viii, 54; interchanges of molecular energies, xvi, 134; ionization of molecules, i, 142, 143; isothermal changes in, iv, 156; latent heat of, 153, 173-4, v, 353, 354 (see Latent Heat); laws not inflexible, iv, 142-3; liquefaction of, 143, 153, 191-2 (see Liquefaction); Mariotte's law, 141; mechanical energy of, 142; molecular velocity in, 133; molecules in, iii, 309, iv, 22, 131, 132-3, 152-3, viii, 23, 24, 106, 305-6; molecules, number in, iv, 133, viii, 108-9, xvi, 133; monatomic, viii, 309; pressure of, v, 223, viii, 24-5, 109-10; pressure, to what due, iv, 30, 132-3; pressure, volume, and temperature laws, iv, 125-6, 139-43, v, 347, viii, 106-8; Regnault's constant, iv, 142; solidifying of, i, 32, iv, 153, 192; solubility in water, viii, 40, 111, 112; sound velocity in, iv, 155-6, 198, 199; specific heat ratio, 155-6, 159; spectra of, ii, 112-13, iv, 361-3; suspended change of state, viii, 113, 304, 305; vibration of, iv, 215; volume taken at atmospheric pressure, v, 223 Gas Lighting, vi, 195, 264; fire hazards, vii, 51 (see also Illuminating Gas) Gas Mantles, viii, 60, 252 Gasoline, combustion of, viii, 13, 52; explosiveness, vii, 124, viii, 23, 54, 62; production and uses, 208, 209, 235 Gasoline Engines, v, 156-61; in aeroplanes, 231; efficiency, 155; compared with motors, vii, 223; operation, 123-33 Gas Plant, xiii, 136-7 Gas Shells, i, 308, 314, viii, 263 Gastric Digestion, ix, 234-6, x, 319-25 Gastric Glands, control of, ix, 162, 240-2 Gastric Juice, viii, 358, ix, 234-8, x, 319-20; control of secretion of, ix, 240-2; conveyance of, 189-90; disorders of, x, 321-3; historical studies of, ix, 239-40; indigestion from failure of, 239-41 Gas Warfare, viii, 262-4, x, 186-8 Gatling Guns, v, 362-3, 364, 380 Gatun Lake, Panama, xiv, 195 Gaurs, xii, 330 Gay-Lussac, balloon ascensions, i, 18; chemical work, xvi, 133, 160, 162 Gazelles, xii, 327 Gearing, in turbine-driven ships, v, 105, 153-4, vii, 329 Gears, v, 25-31; hydraulic, 104-6; spiral, 38-9; toothed, disadvantages, 104; worm, 37 (fig.), 38 Geckos, xii, 205-6 Geese, xii, 257, 258 Gelatine, colloidal state, viii, 314, 315, 356; food value, ix, 288 General Electric Company, autotransformers, vi, 337; bulletin on motor costs, vii, 224-6; machinery for Niagara Plant, vi, 374, 375, 376, 377; Mazda lamps, 267; radio engineering work, vii, 274; small power sets, 232 Generators, vi, 49-56, vii, 369; alternating current, vi, 158-9, 196-216 (see also Alternators); armature reaction, vii, 145-6; direct current, vii, 175-94 (see also Direct Current Generators); efficiency, vi, 192-4, 214-15, 357, 379; electrostatic, 298-301; induction motors as, 249-50; neutral points, vii, 373; operation in power plants, vi, 357-8, 362; of Niagara Plant, 374-5; principal parts, 176; purpose and parts, vii, 367; radio, 274-8, 282-3, 290-1; ratings, vi, 192-4, 214-15; regulation of output, vii, 144-50; short-circuit protection, 49; size of units, vi, 378-9; slow and high speed, 182; turbine-driven, v, 151, 154; use in therapeutics, vii, 236-7, 241-5 (see also Dynamos) Genetics, xvi, 157-8 Geneva Lake, filling of, by Rhone River, xiv, 53; former connections, 185; slow movement of water, 210 Genital Organs, foci of infection in, x, 220, 221 Genius, Bessel on, ii, 93; obstacles and, xvi, 30; reflex action of, xi, 36; Titchener on, 225-6 Genoa, growth of, xiv, 308; sea captains of, 310 Gentians, xiii, 190, 205 Genus, Genera, defined, xii, 28, xiii, 170, 171 Geocentric Theory, ii, 9-10, 34-5 (see Ptolemaic System) Geo-Chemistry, viii, 190-203 Geocoronium, i, 192, 373 Geographical Change, agents of, xiv, 31-2, 33-79 Geographical Cycles, xiv, 29, 34-5, 48 (see Cycles of Erosion) Geographical Distribution, science of, xvi, 140 Geography, changes since prehistoric times, xiv, 29-30; civilization and, xv, 122-3, 128-39; defined, iii, 9-10, 379, xvi, 36; development of science of, 94, 98, 114, 123-4; genetic conception of, xiv, 3-4; history and, 10, 30-1, 191-7, 239-45, 249-50, 261-2, 279-82, 305-11 Geological Ages, iii, 19-21, xv, 71; determined by fossils, iii, 15, 18-19; estimate of lengths, xiii, 314, 322; length seen in coal formations, iii, 201; length seen in chalk deposits, 218; length shown by mosses, xiii, 306 GEOLOGY, Volume iii Geology, daily interest, xvi, 22-5; definition and scope, iii, 3, 9, 11, 12, 378, xvi, 37; history of development, 126, 168-73; mineralogy and, iii, 309 Geometry, of Greeks and Hindus, xi, 239-40; history of, xvi, 54, 68, 81, 89, 90 George, Lake, iii, 145; stream changes around, 243 Georgia, aluminum production, iii, 369; cotton of, xiii, 237; glacial period in, xiv, 376; soil of, 218 Georgian Planet, ii, 267 Geotropism, xiii, 85 Geranium Family, xiii, 200 Geraniums, fertilization, xiii, 136; killed by hot water, 299; multiples of five in, 176; turning to light, 85; petal arrangement, 190 Germanium, discovery, viii, 180; symbol and atomic weight, 383 Germans, in Alpine group, xvi, 49; grouped as Huns, xi, 22 German Silver, copper alloy, viii, 164; resistance, vi, 76, 77 Germany, aeronautical weather service, i, 304; barley growing in, xiv, 365; beet sugar production, xiii, 216; coal deposits, iii, 345; coasts of, xiv, 247; early surgery, xvi, 181; earthquakes of, xiv, 128; forest policy, xiii, 372, xiv, 238-9, 382; geological works, xvi, 170; hail insurance, i, 344; in World War (see World War); loess deposits, xiv, 72; medicine of, Muller's influence, x, 118; meteorological establishments, i, 222-3; meteorology in World War, 309, 310; military aviation development, 40; mining products, iii, 362, 364; moor fires in old, i, 56; mountains of, xiv, 96, 235; nitrogen fixation in, i, 36-7, xiv, 66; plains of, 217; potash deposits, viii, 130, 143, 144, 344, xiv, 67-8, 209; salt beds of north, iii, 204, xiv, 141; "sheep-cold", i, 363; topography of western, xiv, 87 (map), 90; unke toad of, xii, 176 Germ Cells, ix, 324-5, 327, 332, 339, x, 232, xvi, 156, 157-8; in reproduction, x, 233; source of, xii, 27 (see also Germinal Tissue, Germ Plasm) Germinal Tissue, ix, 324-5; chromosomes of, 328, 329, 339; development of germ cells in, 332, 339; heredity dependent on, 325-8; independence of, 325 (see also Germ Plasm) Germination of Seed, after low temperatures, i, 32; acacia plant of Natal, xiii, 375; ancient wheat grains, 211, ix, 16-17; bird-carried seed, xiii, 340, 341; seed in sea water, 346, 348 Germ Plasm, x, 228, 229; immortality theory, 230; origin of energies, xvi, 145; theory of inheritance, x, 233-4, 235, xvi, 156 (see also Germinal Tissue) Germs, disease-producing, (see Disease Germs); in body, ix, 177; universal presence of, x, 193-4 Gestures, language of, xv, 146-52, 167-8 Geyserite, iii, 335 Geysers, iii, 128-9, xiii, 299; artificial, in Michigan, v, 92 Gharials, xii, 199, 201 Ghizeh, Pyramid of, xiv, 78, xv, 270; temples of, ii, 26 Ghor, of Syria, xiv, 120-1 Ghosts, as visual hallucinations, xi, 91 Giant and Dwarf Stars, ii, 153, 294, 309, 310, 382-4 Giant's Causeway, Ireland, xiv, 104; columnar structure, iii, 111, xiv, 129 Gibbons, xii, 381-2; reasoning power in, xv, 67; skeleton compared with man, 59 Gibbs, James E. A., v, 285 Gibbs, J. W., xvi, 136, xvi, 169 Gibraltar, apes of, xii, 378 Gibraltar, Strait of, depth, xiv, 299 Giddiness, sensation of, xi, 126 Giffard, Henri, v, 227 Giffard Injector, v, 140-2, 380 Gila Monster, xii, 204, 207 Gilbert, Dr. William, electrical work, vi, 11-12, xvi, 109, 111, 188 Gilbertus Anglicus, x, 41 Gills, of fishes, xii, 128, 135; functions and structure of, ix, 253, 254 Gills (plant), of mushrooms, xiii, 163 Ginkgo Tree, xiii, 315-16, 326 Ginseng, antiquity, xiii, 324-5; distribution, 351; origin, 255 Giraffes, xii, 320-1; trapping of, xv, 224 (fig.) Giralda Observatory, xvi, 100, ii, 38 Girls, education of, xi, 266-7 Givler, Prof. R. C., author "PSYCHOLOGY," Vol. xi Glacial Bowlders, iii, 70, 237, 352 (Pl. 20), xiv, 69, 70 Glacial Deposits, iii, 66-70, xiv, 59, 60; in U. S. and Canada, 170-1; lakes formed by, iii, 144-6, xiv, 200-2 Glacial Epoch, iii, 236-48; distribution of plants and animals, xiv, 375-7; drainage changes, 30, 52, 164, 170-1; fjords due to 259-61; lakes formed by, iii, 143-51, xiv, 200-2; topographical changes, 3, 30, 59-62, 158, 170 (see also Ice Age) Glacial Periods, theories of, i, 58, iii, 247-8 Glacial Plants (see Arctic Plants) Glacial Soil, xiv, 63, 69-70 Glacial Valleys, xiv, 56-8 Glacier National Park, cliff glaciers in, iii, 60; Swift Current Valley, Plate 5, p. 96; thrust faulting in, 90 Glaciers, iii, 59-62, xiv, 54-5; "autographs of," 56; cirques of, 58; cracks and fissures in, iii, 63; defined, 379; deposits of, 66-70, xiv, 59-60; erosion by, iii, 63-70, xiv, 55, 56, 57-8, 60-2, 233; falls formed by, iii, 48; flow, 62-3, 68, 240-1, iv, 165-6; lakes formed by, iii, 142-51; occurrence, xv, 72-3; topography produced by, xiv, 42-3, 44, 55-62; valleys cut by, iii, 64, 65, 66 (see also Plates 4, 5, and 6); valleys "overdeepened by," xiv, 259-60 Gland Cells, functions, ix, 39, 43, 59; number unchanging, 48 Glanders, germ of, x, 195; immunity to, 207 Glands, activity and blood supply, ix, 220-1; adrenalin effects on, 171; control of, 159-69, x, 346-7; ductless, x, 346-53; energy release by, xi, 24; fatigue effects, xi, 272; nerve connections, ix, 159-60; reflex responses by, xi, 23; with ducts, x, 347 Glare, direct and reflected, vi, 277-8 Glasgow, soot-fall, i, 65 Glass, antiquity of, viii, 269, 280-1, xvi, 73-4; coloring of, viii, 282; colors in X-rays, iv, 378; composition and properties, viii, 281, 304-5; effects on light and heat waves, iv, 183; electrification of, 257, 258, 259; ground by sand blast, 130; heat conductivity, 179; light decomposition by, ii, 100-1; light deviations in strained, iv, 330; light refraction by, 327; sodium compounds in, viii, 137, 146 Glasses (lenses), for various eye defects, ix, 111, 112, 113, 114 Glazed Frost, i, 108, 121, 373 Glidden, Carlos, v, 312 Glisson, Francis, x, 86, xvi, 178 Globefishes, xii, 164 Globigerina Ooze, xii, 18 Globular Clusters (Stars), ii, 336-40; Hyades as, 342; studies of, at Mt. Wilson, 159-60 Globular Lightning, i, 149, vii, 205-6, 213-15 Glory (meteorology), i, 184-5, 373 Glowworms, i, 346; Fabre's studies, xvi, 144 Glucinum, atomic weight and symbol, viii, 180, 383; in calcium group, 148 Glucose, viii, 225-6, 377, ix, 230; converted from cellulose, viii, 255; fermentation of, 225, 248; formula, 219, 225, 229; in human body, 359; manufacture and uses, 228, 243-4; production by plants, 335; use of, by body, ix, 230, 243, 244, 245 Glutton (weasel), xii, 348, 349 Glycerine, viii, 215, 247-8; base of fats, 221, 245; boiling point, 299; melting requirements, iv, 162; production in wine-making, x, 138 Glycogen, xi, 136-7, 138; chemistry of, viii, 228-9, 350; production and storage in liver, 359, ix, 291, 292, 297, 298, x, 329; reconversion into sugar, ix, 293 Glyptodon, xii, 283-4 Gnawers, xii, 285-96 Gneiss, iii, 379; formation, 169, xiv, 19; jointing of, 133 Gnomons, ii, 24, 25, 300 Gnus, xii, 327 Goats, xii, 325-6; horns of, 328; usefulness, 324 Gobar, of Nile region, i, 96 God, conceptions of, xv, 344; ideas of, in Old Testament, 374 Goddard Rocket, i, 22-3 Godman, John, x, 116, xvi, 185 Gods, evolution of belief in, xv, 341-4, 347-8, 357 Goethe, evolution known to, x, 136; on cloud forms, i, 98 Goethals, Panama Canal Zone work, x, 162 Goitre, ix, 303; exophthalmic, x, 272, 276-7, 351-2; removal of thyroid gland in, 349 Gold, atomic weight and symbol, viii, 383; California mines, iii, 226, 365; chemical inactivity, viii, 127-8, 163, 174; contraction on solidifying, iv, 150; density of, 113; electrolytic refinement, vii, 301, 320; extraction methods, viii, 131, 141, 170, 174, 269, 270; fusibility, 384; in sea water, 197, xiv, 295; melting point, iv, 162; metallurgy, development of, xvi, 176; occurrence, iii, 330-1, 365-7, viii, 131, 198; "parting" of silver from, 272; positiveness, vi, 59; production, iii, 365; profitable ores, viii, 197; properties, 126-7, 174, iii, 330-1; recovered in copper refining, vii, 319, 320; specific gravity, viii, 384 Golden Age, x, 18, 20; of Greek science, xvi, 86-96 Golden Gate, formation, xiv, 258; furrow of, 287 Goldenrod, bracts, xiii, 43; stems, 23; in the pampas, 376 Golden Showers, i, 61 Goldfish, family of, xii, 161; in liquid air, i, 32 Gold Leaf, color between glasses, iv, 324 Gold Mining, dredges in, v, 256-7; water jets in, 88 Gold-Plating, of aluminum, vii, 319 Goldschmidt Generators, vii, 274 Goldschmidt Method, of welding, viii, 155 Golf, as exercise, x, 317; report of match, xi, 161 Goodwin, Rev. Hannibal, v, 330 Goodyear, Charles, xiii, 245 Goose Barnacle, xii, 84-5 Gooseberry, origin, xiii, 225 Goose-Flesh, ix, 161, xi, 112-13, 123 Gophers, xii, 290, 294; badgers and, 348 Gopher Snake, xii, 219 Gopher Turtle, xii, 191 Gorals, xii, 325 Gordius (hairworm), xii, 45 Gorgas, William C., yellow fever work, x, 162, 172 Gorges, formation of, xiv, 50-1, 51-2; in old and new areas, iii, 33, 34; of New York and New England, 44, 242-3 Gorham, Marquis L., v, 248, 381 Gorillas, xii, 382 (fig.), 383-4; brain weight of, xv, 62; physical comparison with man, 57-8; family groups among, 276, 360-1; use of stones and clubs, v, 9 Gorner Grat, boiling temperature at, iv, 170 Gouffre, i, 196, 373 Gourd Seed, growth of, x, 229 Gout, uric acid and, x, 343 Government, beginnings of, xv, 360-74, 379-80; cultivation and, 380 Grackle, coloring of, xii, 245 Gradients, meteorological, i, 373 (see Barometric, Potential Gradients) Graduated Flask, viii, 294, 295 Graham Flour, ix, 34 Graham's Law, viii, 108-9 Grain Cradles, v, 240-1 "Grain of the country", xiv, 99; in river classification, 153 Grains, fruit of grasses, xiii, 56, 182; milling of, xv, 237-9; proteins in, ix, 34; "showers", i, 357; storing of, viii, 371 Gram, unit of force, iv, 70; unit of mass, iv, 46, 69, viii, 28; value in pounds and poundals, iv, 70 Gram-Molecular Volume, viii, 109 Gramophone, v, 328-9, 382 Grampuses, xii, 297 Grand Banks, dogfish of, xii, 146; petrels of, 252; scallop fisheries of, 65 Grand Canyon of the Colorado, iii, 40-3, 140, 230, xiv, 83; conical fragments in, 81; outer and inner gorges, 173; plateau of, 124, 159, 220; Proterozoic strata in, iii, 177; rock pyramids in, xiv, 224-5 Grand Canyon of the Yellowstone, iii, 44, and Pl. 2, p. 48; color of rocks in, 26; youthful valley type, 33; relief model of, xiv, 10 Grand Point Tobacco, xiii, 258 Granite, composition, iii, 308, 326, viii, 192-3; disintegration of, 194; igneous nature, iii, 112; jointing of, xiv, 133; mountain cores of, 110-11; occurrence and production, iii, 371; plutonic rock, 13, xiv, 18; weathering of, iii, 22, 27-8, 32 (Pl. 1), xiv, 78-9; wells in, 137 Grapes, acids of, viii, 223; origin and antiquity, xiii, 225, 324-5; true berries, 54; water content, viii, 365 Grape Sugar, viii, 224-5; polarization of light by, iv, 356 Grapevines, xiii, 27, 28 Graphite, iii, 331, viii, 43; in Archeozoic rocks, iii, 173, 249-50; Rhode Island beds, 345; use and production, vii, 308-9, xvi, 190 Graptolites, iii, 259, 266 (fig.), 267 Grasp, in infants, ix, 349, xv, 61; of man, ix, 67-8; grasping importance and organs of, 82; reflex processes in, 157, 349 Grasping Reflex, xi, 40-5, 59 Grass, blue-eyed, xiii, 189; leaves of, 176; monocotyledon, 178; veins, 32 (see also Grass Family) Grasses, dominant on prairies, xiii, 350, 374; evolution, iii, 251, 257; fertilization, xiii, 148; first appearance, 319; true and incorrect, 179, 180; water requirements, xiv, 381 Grass Family, xiii, 179, 181-3 Grasshoppers, xii, 108-10; jaws of, 100 Grasslands, xiii, 373-7; contests with forests, 348-9, 368 (illus.), 374-5, xiv, 380-1; distribution of, 380, 381; economic importance, 383-4; vegetation of, 380, 381 Gratitude, sentiment of, xi, 147 Graupel, i, 107, 373 Gravel, rocks formed from, iii, 13, 53 (see Conglomerate); sedimentary rock, xiv, 18 Grave Sacrifice, custom of, xv, 336 Graves, Robert, x, 112 Graves Disease, x, 351-2 Gravitation, universal, discovery and laws, ii, 63-72, iv, 20, 95-8, xvi, 115-16; Einstein theory, ii, 79-82; magnetic force compared with, iv, 249-50; nature of, ii, 78; things unexplained by Newton's laws, 73-4, 78-82; various applications of Newton's laws, 77, 78, 375, 380 (see also Gravity) Gravitation Units, iv, 64, 70 Gravity, ii, 63-4, 69, iv, 65, 109; acceleration of, 65; center of, 99-101; direction of earth's, 98-9; force in falling bodies, 42, 65, xvi, 32; gyroscope and, v, 335, 336, 337-9; Huygens's studies, ii, 58; on asteroids, 257; on moon, 199, 204; on sun, 168; Richer's observations, 59; water-power due to, v, 76-7, 139; weight due to, iv, 58, 74, 109 Gravity Battery, iv, 297, vi, 137, 140-1 Gravity Faults, xiv, 115 Grayfish, i, 224 Graylings (fish), xii, 159 Gray Matter, ix, 124; of brain, xv, 63 Great Auk, xii, 265 Great Basin, block mountains in, iii, 138-9; drainage changes in, xiv, 188; faulting in, iii, 89, 229, xiv, 117, 127; formerly submerged, iii, 181; not being worn down, 32; saline lakes of, xiv, 206; streams, base level of, 164; wind-eroded materials of, iii, 73 Great Britain, aerial travel statistics, i, 50; aeronautical research, 51; animals of, xiv, 272-3; coal supply, iii, 345; coast destruction, xiv, 46; empire of, 279; geology related to continent, 271-2; manufacturers, American System in, v, 50; manufacturing future, 173; rainfall of, xiv, 41; recent separation from continent, 30, 271-3; serpents of, xii, 218; soot studies, i, 65; standard units in, iv, 45-6; storm signals, i, 282; thermometer scale in, iv, 136; tides of, xiv, 293-4 "Great Eastern," steamship, v, 193 Greater Antilles, geological history of, xiv, 274-5 Great Indian Earthquake, xiv, 333, 334, 335, 336 (fig.); cause, 340 Great Lakes, commerce on, xiv, 62, 212; fish of, xii, 156, 159; former drainage farther north, iii, 46; level changes in region, 82; origin and history, 146-51, xiv, 61, 62, 201-2, 203; recentness of formation, iii, 12; recessional moraines near, 67; sewage disposal in, viii, 325; sizes and depths, xiv, 204; water supply of Lake cities, 140 Great Plains, elevation of, xiv, 27, 213; evaporation in, 135; geology of, 215; grasses of, xiii, 181, 374, xiv, 380, 381; horses of, xii, 306, 307; pronghorns on, 322-3; red beds, iii, 208; rejuvenation, 230; rodents of, xii, 294; stock-raising on, xiv, 383-4; trees in, xiii, 372-3, 374, xiv, 372; volcanic action in, 318; wind-fertilization of plants, xiii, 149 Great Rift Valley, xiv, 117-21; lakes in, 203; volcanoes of, 317 Great Salt Lake, crustal warping at, iii, 82; history and formation, 152-3, xiv, 207-8; mirages, i, 172; plain of, xiv, 215-16; salt in, iii, 374, viii, 139, 140, 275 Great Sea Waves, xiv, 337-343 Grebes, xii, 250-1 Greece, earthquakes of, xiv, 332, 333-4; geographical changes in, 33; rainfall of, 358; rift valleys in, 123 Greece (ancient), astrology in, ii, 21; Babylonian influences, xvi, 63; civilization conditions, xv, 123; civilization pictured in Odyssey, 324; copyists of, 178-9; foreigners called barbarians, xi, 22; Golden Age, x, 20, xvi, 86-96; musical instruments, xv, 316, 317 (fig.); northern invasion, xiv, 281; religion and science associated, xvi, 44; slavery in, xv, 378-9; timing of orators, v, 62; weather records, i, 67-8 Greek Astronomy, ii, 10-11, 27-36, xvi, 81-2, 90-1 Greek Language, xv, 162 Greek Medicine, x, 16-25, xvi, 95-6; preservation and revival of, x, 31, 36, 43-4, 45 Greek Philosophers, remarks on, ii, 27, 30; on origin of earth, 366-7 Greeks (Ancient), boiling of foods unknown to, xv, 233; degeneration of stock, xvi, 96; gods of, xv, 343, 352; idea of insanity, x, 356, 357; idea of soul, xv, 330; in Mediterranean group, xvi, 49; intellectual height, 50; knowledge of loadstone, vi, 28, 29; monsoons used in navigation, i, 130; oar-propelled ships, xiv, 265; plants known to, xiii, 215, 216, 253; sacrifices of, xv, 347-8; scientific bent, xvi, 54; superstitions of, xv, 355; surveying inventions, xvi, 68-9; trade and colonies of, xiv, 307 Greeks (modern), in Alpine group, xvi, 49 Greek Science, xvi, 75, 76-96; debt to Egypt, 75; influence on Copernicus, 102; Roman development of, 99; spread and continuation of, x, 23, 25 Greek Sculpture, xv, 302 Greek Vases, xv, 251, 253 (fig.) Green, complementary color of, iv, 367; effect on blood pressure, xi, 63; in interior decoration, vi, 274; primary color, iv, 366; seeing of, in color-blindness, ix, 116 Green Flash, i, 170-1, 373 Greenhouses, effects of glass on heat, i, 59, iv, 183; electric lighting, xiii, 76 Greenland, climate, xiv, 345; discovery, 261; fjord coasts, 258, 259; foxes of, xii, 344; glaciers of, xiv, 55; ice sheets, iii, 61-2, 237; marriage customs in, xv, 282-3; mirages, i, 173; ocean colors near, xvi, 147; rainlessness, i, 109; winds, 128, 129 Greenland Ranch, Cal., i, 209 Green Mountains, iii, 188 Green River, Uinta Mts., xiv, 166, 168, 175 Greenwich Observatory, founding of, ii, 83, xvi, 124; publications, 125 Grenville Strata, iii, 165-8 Grew, biologist, xvi, 112, 116, 126 Greylock, Mount, iii, 232 Grief, exhaustion from, xi, 135-6; expression of, by monkeys, xv, 65 Ground Sharks, xii, 143 Grinders, invention, v, 48, 381 Grip, disease, x, 294-5 Grison, xii, 349 Ground Moraines, iii, 67 Ground Pines, iii, 254 Groundsel, seed disposal, xiii, 345 Ground Water, iii, 113-29, xiv, 135-52; how plants absorb, xiii, 91-3; landslips facilitated by, xiv, 233; mineral concentration by, iii, 126, xvi, 173; petrifaction by, iii, 15, 126-7; rivers and, xiv, 157 (see also Soil Water) Ground Wires and Plates, vii, 369 Groups, Chemical, viii, 93, 377; interchange principle, 211; ionization, 121-2; nomenclature, 97; valences of, 94 (see also Radicals) Groups (human), formation of, x, 9, xv, 361-3 Grouse, xii, 261 Growing Season, i, 373 Growth, age in relation to, ix, 47-8, 288-9; by cell division, 43-8; chemical regulation of, 169-70; food requirements for, 31-4, 286-8, 295; life and, xii, 13; metabolism of, ix, 38-9, 295; of bones, 56, 58; of skin, 312; of various tissues, 47-8, 286-7; of skull, xv, 40; rate of, in man, ix, 32 (diagram); vitamines necessary to, x, 261, 262 Gruener, Prof. H., author CHEMISTRY, Vol. viii Guam, ocean depths near, iii, 51 Guango Tree, i, 350 Guatemala, Santa Maria eruption, xiv, 328-9 Guava, xiii, 196, 225 Guayaquil, sanitary measures, i, 327; yellow fever campaign, x, 173 Guericke, Otto von, iv, 29, 116, xvi, 110 Guillemots, xii, 264-5 Guinea Pigs, xii, 289; anaphylaxis in, x, 213 Gulf Coastal Plain, xiv, 214; chalk deposits, iii, 266; Cretaceous deposits, 216; geological history, 222, 231 Gulf Stream, climatic influences of, viii, 37, xiv, 304; meeting with Labrador current, 305; origin and course, 304; "paper sailors" of, xii, 78; plan for protecting, i, 345; Portuguese man-of-war in, xii, 37; seed dispersal by, xiii, 346 Gull, Sir William, xvi, 180, 184 Gulls, xii, 264 Gum Arabic, source, xiii, 226 Gumboils, ix, 56, 187 Gums, composition of, viii, 223, 229; electrical conductivity, iv, 259 Gums (mouth), chilling of, by ether, iv, 174; germ infection through, x, 202, 219, 222 Guncotton, composition and action, viii, 63, 255, 261; discovery, xvi, 163 Gunite, v, 136 Gunnison River, Colorado, xiv, 172-3, 175 Gunny Sacks, xiii, 241 Gunpowder, viii, 144-5; explosion, v, 156-7, viii, 62, 145; introduction, v, 361, 368, xvi, 101 Guns (big), v, 368-71; locating of, by sound velocity, i, 313, iv, 201-2; making of, v, 323-5; operation on battleships, v, 104, vii, 333-4; phenomena in World War, i, 193-4 (see also Artillery, Projectiles) Guns (small), development of, v, 361-2, xv, 213, 216-19; kick, v, 143; kick utilized in Maxim gun, 363; machine, 362-8; percussion lock invention, 377; standardization in manufacture, 49-50 Gunshot Remedies, vii, 241, x, 76 Gunter, Edmund, xvi, 104 Gushers, oil, iii, 353-4 Gusts, i, 295, 373 Gutenberg, Johann, v, 300; printing invention, xv, 179 Guttation, of plants, i, 350-1 Guyon, Felix, xvi, 184 Gymnarchus Fish, xii, 154 Gymnastic Exercises, x, 304-5 Gymnosperms, xiii, 174, 175, 178; alteration of generations, xvi, 166; first appearance, iii, 252, 255 (see also Conifers) Gynecology, development of, x, 80-1, 122, xvi, 180 Gypsum, iii, 331-2, 375-6; composition, viii, 153; deposits and use, xiv, 209; in sea water, 295 Gyro-compass, iv, 254-5, v, 201, 340, 384 Gyroscope, iv, 254-5, v, 335-44, 384; in torpedoes, 373 Gyroscopic Action, of bullets and shells, v, 362 Haber Process, i, 36-7, viii, 74, 105, xvi, 165 Habit, xi, 247-58; autosuggestion and, 306; in physical functions, ix, 81, 88, 251; slaves of, xi, 263; will and, 261 Habits of Thought, xi, 198, 203-4, 247 Habitual Images, xi, 222 Hackberry Tree, xiii, 194 Haeckel, Ernst, biological work, x, 136, xvi, 182; on phosphorescence of sea, xii, 18-19 Hail, i, 106-8, 373-4; formation, 120; storms and stones, 119-20 Hail clouds, i, 102 Hail Insurance, i, 269, 344 Hail Rods, i, 341, 342-3, 374 Hail Shooting, i, 341-2, 374 Hailstorms, devices to avert, i, 340-4 Hair, cells of, ix, 13; color and form in different races, xv, 37-8, xvi, 48, 49, 50; cutting of by electricity, iv, 10; dyeing of, x, 58; emotion effects on, xi, 142; erection of, ix, 161, 162, 166, xi, 113; of mammals, xii, 270-1; on face and body, xv, 38 Hairdressing, among savages and Chinese, xv, 260-1; ancient Egyptian, 255 (fig.) Hairsprings, v, 70, 71-2 Hairworms, xii, 45 Hags (fish), xii, 130, 131 Haiti, gouffre of, i, 196; rubber growing, xiii, 245; words derived from, xv, 161; yellow fever of, x, 160; zoölogy of, xiv, 274 Hakemite Tables, ii, 38, 39 Hale, Prof. George E., ii, 147, 148, 177, 178, 225, 241; spectroheliograph of, 129, 183 Hales, Stephen, x, 88, xvi, 112 Halite, iii, 332 Haller, Albrecht von, x, 77, 87-8, 97, 98; medical works, xvi, 178 Halley, Edmund, comet and other discoveries, ii, 83-9; discovery of moon's deviations, 73; discovery of star motions, 304; on Eta Argus, 324 Halley's Comet, ii, 84, 85-6, 273-4, 275, 281; tail of, 134 Hallucinations, definition and kinds, x, 358; of crowds, xi, 328-9; visual, 91 Hallucinatory Images, xi, 221 Halogenation, viii, 266, 377 Halogen Derivatives, viii, 210, 211-12, 236 Halogens, viii, 18, 84-7, 377; similarity of, 176 Halos, i, 177-183, 374; circumscribed, 181, 369; tangent arc, 383 Haly, "Royal Canon," of, x, 32, 37 Hamadryad, xii, 228-9 Hamburg, Deutsche Seewarte, i, 223, 276; harbor of, xiv, 270 Hamilton Mill, vi, 296, vii, 209 Hamilton, Mount, ii, 142 Hammers, measurement of blows of, iv, 67; pneumatic, i, 28 Hammurabic Code, xvi, 63; on medical practices, x, 15 Hands, ape's and human compared, xv, 57, 58-60; bones of, ix, 67-8; cold or warmth felt in, 320; color in different lights, iv, 364-5; deftness of human, v, 248; evolution of, xii, 167-8; grasping reflex of, ix, 349, xi, 40-5; importance in child's education, 43; origin of flexed position, 42-3; reciprocal innervation, 86; tools resembling, 44-5; temperature of, ix, 93; X-ray pictures of, iv, 55 Hangars, i, 43 Hanging Glaciers, iii, 60-1 Hanging Valleys, iii, 65, xiv, 57 Hanks, of yarn, v, 272 Hanseatic League, xiv, 28, 308 Harbors, xiv, 266-71; necessity of, to modern ships, 265; photographic mapping of, i, 47-8 Hard Coal, combustion process, viii, 45; flames from, 57; origin, xiii, 10 (see Anthracite Coal) Hardening of Arteries, x, 334-6, 340 Hardening Processes, (health), x, 240 Hardness, defined, viii, 377; scale of, iii, 320, viii, 202; sensation of, xi, 128 "Hard Shell," xii, 83 Hard Water, cause, iii, 126, viii, 151, 322-3, 377; effects of, 143, 151-2, 323; effects, xiv, 147; occurrence in nature, ii, 147; softening of, viii, 323-4; taste of, 40 Hares, xii, 286-8 Hargreaves, spinning jenny, v, 273, 376, xv, 246 Harmattan, i, 134, 374 Harmonica, iv, 235 Harmonics, iv, 213 Harmony, due to tonal fusion, xi, 106 Harney's Peak, xiv, 227 Harpoons, xv, 209 (fig.), 210-12 Harps, development of, xv, 318 Harpsichord, xv, 318 Harrisburg, Pa., topography near, iii, 36 Harrison, John and William, v, 66-7 Hartness, telescope of, ii, 101 Harun-al-Raschid, astronomy under, ii, 37 Harvard Classification of Stars, ii, 116-18, 146, 310 Harvard College, first eclipse expedition by, ii, 211 Harvard Football Team (1913), excitement effects, xi, 138 Harvard Observatory, Arequipa station, ii, 145-6, 148; photographic work, 116, 118, 127, 130, 136, 137, 301-2; star spectra studies, 307 Harvard Photometry, ii, 297 Harvesting Machines, ancient, v, 240; modern, 244-9 Harvestmen (scorpions), xii, 90 Harvest Moon, ii, 196 Harvey, William, x, 61-2, 66-7, 97; discovery of circulation of blood, ix, 192, x, 22, 61, 63-6, 69, 81, xvi, 106-7, 142; other work, 107, 111 Hashish, xiii, 239 Hate, emotion of, xi, 139; motor character, 58; sentiment of, 148-9 Hats, hygiene of, x, 240, 309; renovation by electricity, iv, 10 Havana, harbor of, xiv, 268; sanitary measures, i, 327, x, 162; water supply, xiv, 140 Havemeyer, Dr. L., author ANTHROPOLOGY, Vol. xv Havre, port of, xiv, 271 Hawaii, geological formation, xiv, 101; paper in sugar-growing, v, 291; radio station, vii, 281; screw pine of, xiii, 354 Hawaiian Islands, lava formations, iii, 28, 103; oceanic character, xiv, 276; rainfall on Mt. Waialeale, i, 112; trade wind effects, xiv, 356; volcanic soils, 329; volcanoes, iii, 103-5, xiv, 322-3 Hawaiian Music, xv, 315 Hawk Moths, xii, 119-20; facets of, 102 Hawks, xii, 260, 261; man's lesson from, xv, 206 Hawksbee, Francis, xvi, 122-3 Hay Fever, cause of, x, 212, xiii, 118 Haze, atmospheric, i, 374; dry fog, 96; dust (African coast), 55; from smoke, 56, 57; in distance perception, xi, 182 Hazel Copses, xiii, 370 Hazelnut Tree, xiii, 193 Head, binding of, among savages, xv, 260; blood supply of, ix, 197; bones of, 61-3; motions and position, how sensed, 90; saving heels by, xi, 376-7; shape in race classification, xv, 42-3; washing of, x, 312; word, various uses of, xv, 158-9 Headaches, electrical treatment, vi, 285, vii, 238-9; eyestrain and, ix, 113; hypnosis and, xi, 315; significance of, 120-1 Head of Water, v, 94; high and low, 79-81 Health, care of, instruction in, x, 282-5 (see also Personal Hygiene); dependent on kinetic system, xi, 61; emotions and, 129; mental efficiency and, 369; regulation to environment, x, 249-50; resistance to disease strengthened by, ix, 185-6; Science of, vol. x; worry and, ix, 167 Health Resorts, i, 331 Hearing, iv, 203-4, 211-12, ix, 98-103, xi, 98-108; "arrival platform" for, ix, 146; colored, xi, 222; direction perception by, ix, 117, 120; distance perception by, 121; ear movements and, 82; in fishes, xii, 137-8; in insects, 101; limits (vibration rates) of, iv, 204, ix, 99, 100; nerve of, 30; organ of, position, ix, 61; sense of, in infants, 351; space perception by, xi, 163, 167-9 Heart, anatomy and operation of, ix, 200-12; of, x, 332, 333-4; as seat of affections, ix, 200; emotion effects on, ix, 200, xi, 135, 136-7; emotions attributed to, 130-1; examination methods, ix, 205; exercise effects, 261-2, x, 303, 304-5; fatigue effects, xi, 272; fear and terror effects, 131, 132; high temperature effects, x, 251; hypertrophy of, 331-2; motions, Harvey on, 64-6; nerve centers and control, ix, 168; part in maintenance of life, 21-3; passage of blood through former ideas, x, 52, 62, 65-6; removed from body, beating of, ix, 84; rest and sleep needs (eight-hour day), 209-10; septum of, x, 66, 113; sleep effects, xi, 283; sounds, how listened to, ix, 205-6, x, 108-9; supposed "pores" of Galen, 52, 62, 65-6; systole and diastole, 64-5, 109; valves of, ix, 202, 204, 206-7, x, 332; work of, how measured, ix, 213-14 Heart Beat, ix, 202-3; adrenalin effects, 171, 172, 209; chemical theories of, x, 84; control through nerve centers, ix, 168; disturbances of, x, 333; emotion effects, ix, 166, 209; exercise effects, 168-9, 207, 208-9, 261-2; rate of, 203, 204-5, x, 334; rate increased by heat, 251; rate in infants, ix, 347; sounds of, 205-6; variations in rate and vigor, 207-10 Heartburn, ix, 232 Heart Disease, atmospheric conditions best for, x, 241; digitalis in, 333, 383; early ignorance, xvi, 180-1; modern therapy of, x, 382-3; rheumatism and, 224; valvular, 332 Heart Failure, x, 333; symptoms accompanying, 340-1, 344 Heart Muscle, ix, 74-5, 84, x, 333-4; "eight-hour day" of, ix, 210; hypertrophy of, x, 331-2, 335; nervous control of, ix, 207-335; nervous control of, ix, 207-9 Heartwood, xiii, 24, 25, 26, 177 (fig.) Heat, absorbers of, iv, 182; absorption by colors, x, 309; absorption by gases, viii, 309; absorption by mixtures, iv, 175; artificial, man's dependence on, ix, 308; available supply in universe, iv, 193; bacteria destroyed by, viii, 332; "caloric" or "imponderable" theory, iv, 47, xvi, 125; capacity, iv, 154-5; change of state by, 151-3, 192-3; chemical reactions and, viii, 12, 15, 53, 62, 95-6, 100, 308, 360; chemical reactions hurried by, 310; "closeness" due to, ix, 268-9, 270; compression and, i, 26-7, 90, v, 126-8, 161, 351; conduction and conductors of, iv, 138, 176-7, 178-9, x, 307, 308, 309; convection of, iv, 139, 177-8; demagnetization by, 253, vi, 34-5, 38, 117; direction of flow of, iv, 190, v, 351, xvi, 135; effects of, on bodies, iv, 144-59; electrical production of, iv, 310-12, vii, 89, 337-8, 303-5, viii, 283-4; electricity generated by, vi, 340 (see also Thermal Couples); electromagnetic theory, vii, 371; energy form, iv, 138, 140, 189; "engineer" of physics, 50; entropy, iv, 193; expansion by, i, 27, iv, 134-5, 138, 140, 145, 151, viii, 25, 107; forms, ii, 383; from charcoal, viii, 186-7; from foods, 361, 367, x, 269, 271; from infrared waves, iv, 366; from moon, ii, 200; from radium, viii, 186-7; from sun, ii, 169-71, iv, 181-2, 183, 194, ix, 25-6; insulators, iv, 178, 184-5, vii, 307-8; kindling temperature, viii, 53-4; latent (see Latent Heat); measurement for fuels and foods, viii, 360-1; measurements, physico-chemical, 307-8; measurement of quantity of, iv, 154; mechanical equivalent of, (see Mechanical Equivalent); mechanical (dynamical) theory of, iv, 48-9, 140; molecular activity and, iv, 138-9, 140, viii, 25, 37-8; motive power, xvi, 135; of earth's interior, iii, 108, 120-1, 160, 162, v, 178-81, xiv, 11-16, 31-2, 312; of electric arc, iv, 311, vi, 280; of electric lamp, vi, 268; of volcanoes, iii, 106; power from, v, 139-54, 351; pressure of gases increased by, iv, 140; production, electrical, 310-12; production of, by friction, iv, 48-9; production by mixtures, 174-5; production by solidification, 160, 161; radiant energy, vibration rate, ix, 114, 115; radiation of, iv, 180-4; reflectors of, 182-3; resistance of charcoal, vii, 306; rolling friction and, v, 204; scientific meaning of, iv, 139-40; sensation of, ix, 93, xi, 109, 113-14; shrinkage in relation to, ii, 170 (see Lane's Law); solvent action and, viii, 112; specific, iv, 155-6, viii, 308-9; "stuffiness due to", i, 321, x, 237-8; temperature and, iv, 14-45; thermodynamic laws, 189-90; transmission through bodies, 176-9; transmission through space, 180-4; units, iv, 154, 189-90, vii, 369, viii, 374, x, 269; universal presence, v, 345; vacuums, v, 345-58; wastage in engines, v, 155, 161, 165-6, 351 (see also Heat Waves, Temperature) Heat Engines, iv, 192, 193-4, xvi, 135 Heat Equator, xiv, 347 Heating, dynamic, i, 90 Heating Systems, iv, 185-7; dryness from, xiv, 353; water advantages in, iv, 162 Heat Lightning, i, 148, vii, 205, 213 Heat Prostrations, ix, 316 Heat Regulators, vii, 87-8 Heat Stroke, x, 251-2, 274 Heat Thunderstorms, i, 138, 151, vii, 217 Heat Waves, vi, 119, 269, 270, vii, 371; length and frequency, 260; transmission of, iv, 180-4; volcanic dust effects, i, 59 Heath Family, xiii, 202; shrubs of, 274 Heavier-than-air Machines, v, 230-8; principles, i, 286-9; remarks on, vii, 76 Heberden, William, x, 104 Hebrew Language, xv, 162; religious words from, 161 Hebrews, hemp fiber unknown to, xiii, 239; ideas of insanity, x, 356; unclean animals of, xii, 311 Hedgehogs, xii, 366, 367 Heidelberg Man, xv, 92, 93-5; period of, 102 Heidelberg Race, xv, 96-7 Height, human, at morning and night, ix, 65; rate of growth, 32; of various races, xv, 38-9 Heights, oceanic, xiv, 286 Helicopter, i, 42 Heligoland, coast destruction, iii, 56 Heliocentric System, ii, 43-4; known in Egypt, xvi, 69; taught by Aristarchus, ii, 28 (see also Copernican System) Heliometer, ii, 311 Helioscope, ii, 172-3 Heliotaxis, xi, 52-3, 61 Heliotropism, in hydroids, xii, 34 Helium, atmospheric, i, 11, 12, ii, 232; boiling and freezing points, iv, 173; critical temperature, 173; density of, 113; discovery, i, 12, viii, 302, xvi, 194; frozen, v, 345; liquefaction, i, 32, xvi, 194; liquefaction temperature, v, 348; molecular velocity in, iv, 133, viii, 185, 186; monatomic, viii, 309; production by disintegration, i, 12; specific heat ratio for, iv, 156; symbol and atomic weight, viii, 383; use of, in balloons, iv, 108 Hellbenders, xii, 171-2 Hell Gate, tidal race of, xiv, 294 Hellgrammite, xii, 106 Helmets, modern, xv, 221 Helmholtz, chemical work, xvi, 142; "Conservation of Energy," 181-2; contraction theory, ii, 380; medical work of, x, 131; on Young, 97; pupil of Muller, 118, 128; sound studies, iv, 52, 233; theory of life, xii, 9; thermodynamic studies, xvi, 136; theory of color vision, x, 96 Heloderma, xii, 207 Hematite, iii, 332, 356, 358, viii, 47, 156 Hemlocks, in class of conifers, xiii, 174; foliage, 270-1; planting conditions, 270; poison, 250; roots, 17; in northern forests, xiv, 372 Hemoglobin, ix, 181-3, 184, 258-9, 275, x, 337; deficiency in anemia, 337 Hemorrhages, blood transfusion in, x, 338; low blood pressure in, 336; prevention of, in surgery, 14, 148; stopping of, ix, 179-81 Hemostat, x, 148 Hemp cellulose composition, viii, 254; sources, xiii, 238 Hemp Plant, xiii, 238-9 Henna Dye, of Amatus, x, 58 Henry, induction unit, iv, 285 Henry, Prof. Joseph, i, 189, vi, 24, xvi, 191; induction unit named for, iv, 285 Henry I, (England), arm's length of, iv, 45 Henry the Navigator, xiv, 309 Henry Mountains, iii, 139, xiv, 109, 227 Hens, language methods of, xv, 141 Heraclitus, on change, xvi, 79 Herbivora, xii, 300-31; intestine length in, ix, 246 Herbs, antiquity, xiii, 319, 310; in American summer forests, 368, 369; as class of plants, 175; fossil and existing species, 324; garden, 289; hairy covering, 104-5; none among gymnosperms, 175; planting table of annuals and perennials, 290-7; stems, 23; in temperate forests, 366 Hercules (constellation), star clusters in, ii, 336, 340; stars moving from, 305 Herd-Instinct, x, 9 Hereafter, primitive conceptions of, xv, 332-6, 339, 340, 345 Heredity, x, 227-8; diseases and, ix, 103, 181, 304, x, 234-5, 292, 303; importance in human evolution, xvi, 47; importance of knowledge of, x, 236; laws and facts of, ix, 325-44, x, 228-34, xiii, 326-7, 331-4, xv, 22-3, 24, 27, xvi, 153-8; social, xv, 30-1 Hering, Prof. D. W., author PHYSICS, Vol. iv Hering's Illusion, xi, 189 Hermit Crab, xii, 85 Hernia, operations for, x, 14, 41, 57 Hero, Greek scientist, inventions, xvi, 91, 92, 93; mathematical work, 95; steam turbine, v, 142-4, 148, xvi, 92, 93 Herodotus, Barton on, x, 20; on fossil shells, iii, 14; on Egyptian geometry, xvi, 68; on Nile River, xiv, 71 Heroism, in crowds, xi, 326-7, 330 Herons, xii, 254-5 Herophilus, x, 23-4 Herring, xii, 154, 156; limacina and, 19 Herschel, Caroline, ii, 104 Herschel, Sir William, astronomical work, ii, 15-16, xvi, 124-5; discovery of Uranus, ii, 267; father of descriptive astronomy, 139; ideas of nebulæ, 368-9, 380; knighting of, 254; on habitability of sun, 252; on proper motion of stars, 305; picture of solar system, 162-3; reflectors of, 103, 104; studies of Galaxy, 352; studies of Mars, 227; studies of nebulæ, 358 Herschel, Sir John, dismantling of telescope by, ii, 104; on spectrum lines, 112; on Galaxy, 352; studies of nebulæ, 358-9; studies of star clusters, 336-7 Hertz, Heinrich, vi, 25, vii, 258, xvi, 191 Hesperornis, xii, 242 Hesperus, ancient name of Venus, ii, 191 Hessian Fly, i, 256 Hetchy-Hetchy Canyon, iii, 225 Heterodyne Receivers, vii, 278-9 Heterogeneous Rivers, xiv, 154-5 Heteromecic Numbers, xvi, 80 Hevelius, astronomer, ii, 57, 85; telescopes of, 48, 99; halo of, i, 374 Hewson, William, x, 88, xvi, 179 Hexane, viii, 206, 224 Heyl, Henry, v, 330 Hi and Ho, Chinese astronomers, xvi, 56-7, ii, 22 Hicetas, Greek astronomer, xvi, 81, 102 Hickory Trees, in American forests, xiv, 373; in apetalae group, xiii, 190; family, 191; fertilization, 148; leaves, 36-7; leaf-bud protection, 34; roots, 17; sexes in, 46, 191 Hides, drying and tanning of, viii, 257 Hieroglyphics, Egyptian, xv, 172-4 High Blood Pressure, ix, 214, x, 334-6, 340 Highbrow, xv, 43 High Cost of Living, results in disease, x, 268 High Frequency Circuits, vii, 263 High Frequency Generators, vii, 290-1 Highlands, and lowlands, xiv, 213 Highlands-of-the-Hudson, iii, 188, 189 Highs, High Pressure Areas, i, 135-6, 137, 374; movements, 134-5, 237; weather significance, 236, 237; winds in relation to, 125 (see also Pressure Areas) Hill, James J., quoted, xi, 377 Hill, Prof. Leonard, i, 319, 320, 321, 322 Himalayas, animals of, xii, 288, 322, 325, 330, 337, 357; forming of, iii, 236, xiii, 319; glacial erosion in, xiv, 233; height and importance, xv, 137; impressiveness of, xiv, 9; rainfall, i, 111; rainfall on opposite sides, xiv, 355; rhododendrons and azaleas in, xiii, 202; rivers of, xiv, 167; site formerly submerged, iii, 235; sky line from Tibet, xiv, 234; snow pinnacles, i, 117; youthfulness, xiv, 96, 235 Hinds, xii, 317 Hindu Language, words from, xv, 161 Hindus, animal worship of, xv, 334; astronomy, ii, 21, 26; belief concerning trances, ix, 11, 17, 266-7; cloud classifying by ancient, i, 97; conception of earth, ii, 36; crocodile veneration by, xii, 201; geometry of, xi, 239; in brown race, xv, 37; marriage ceremonies of, 292, 293; medicine and surgery of, x, 13-14, 57, 100, 123; monkeys revered by, xii, 379 Hip Joint, dislocation of, ix, 67, 71 Hipparchus, ii, 10, 30-2, xvi, 90-1; data gathered by, 94; discoverer of precession, ii, 70; novae observed by, 331; star catalogue of, 300 Hippocrates, x, 18-22, 97, xvi, 95-6, 106; aphorism of, x, 192, 379; description of diseases by, 17; humoral doctrine, 21, 98; influence in Middle Ages, 31-2, 34, 36, 37; "Oath" of, 18-19; references to teachings, 55, 78, 154, 244, 289; revival of teachings of, 44, 47, 48, 72, 73, 74 Hippopotamus, xii, 310; trapping of, xv, 225 Hiqua, xii, 74 His, Wilhelm, x, 131 Histology, defined, xiii, 75 History, beginnings of, xv, 322, xvi, 51; climatic influences, xiv, 29, 357-9, 361-2, xv, 123; crowds and individuals in, xi, 333; emotions in, 130; geographical influences, xiv, 10, 30-1, 191-7, 239-45, 249-50, 279-82, 305-11, xv, 122-3, 136-9; poetry and, 323-4; sentiments the moving force, xi, 150; suggestibility and records, 310; warriors and artisans in, v, 15 Hoang-ho, shifting of courses, xiv, 184 Hoarfrost, i, 121, 258, 374 Hoatzin, xii, 241 "Hobble-Skirt" Cars, vii, 184 Hoe Printing Press, v, 301, 379, 381 Hoffmann, Friedrich, x, 85-6 Hogs, descent of, xii, 310; embryological development, xv, 54, 55; feeding garbage to, viii, 330 Hohenbergia, leaves, xiii, 106 Hohenheim, Aureolus von (see Paracelsus) Hoists, in power plants, vi, 353 Holland, commercial history, xiv, 262, 280-1, 310; low elevation of, 247; rain-deposited salt, i, 60; vaccination in, x, 103; windmills, i, 37; Zuider Zee of, xiv, 45-6 Holland Submarine, v, 382 Holly, American, xiii, 367 Holmes, Dr. Oliver Wendell, x, 114; anesthetics named by, 125; "goodly company" of, 134; puerperal fever studies, 114-15, 122; quoted, on therapeusis, 75 Holmium, symbol and atomic weight, viii, 383 Holothurians, xii, 23 Holyoke, Mount, xiv, 111 Home, electrical appliances in, iv, 10, vii, 73-90; electric wiring, 67-8; lighting and lighting systems, vi, 274-8, vii, 68-72, 75 Homer, historic value of poems, xv, 323-4; medical references in, x, 16-17; on blood showers, i, 55; on the loadstone, vi, 29 Hominy Block, xv, 238-9 Homogeneous Rivers, xiv, 154 Honey, as food, ix, 292; purpose in flowers, xiii, 124, 126, 142-3, 184; "showers" of, i, 357 Honeydew, on plants, i, 351-2, 357 Honeysuckle, Italian, fertilization, xiii, 142-3; leaf arrangement, 38; tendril movement, 111 Hood, Mount, beauty of, xiv, 315; cone of, iii, 226, xiv, 100-1, 225 "Hoodoo Country," xiv, 105 Hoofed Animals, xii, 300-31; evolution, iii, 299, 300 Hooke, balance spring invention, v, 65; geological work, xvi, 126; light theory, 137; microscope invention, x, 67; microscopic work, xvi, 112; on protoplasm, 166 Hooker Telescope, ii, 148, 156, 157-8, 159-60 Hookworm, campaign against, x, 171, 174-5; parasite of, 199, 201; in tropics, xiv, 357 Hookworm Anemia, x, 337 Hoosac Tunnel, drills in building, i, 27 Hope, physical effects, xi, 339 Hopkins, Dr. A. D., i, 255, 256, 367 Hop-vines, xiii, 27, 111 Horizontal Rainbows, i, 177 Hormones, ix, 170, 171, 189, 303, x, 320, 331, 347; disease poisons as, ix, 178 Hornbeam, family, xiii, 193; European, 271-2 Horneblende, iii, 321; chemistry of, viii, 193 Horned Screamers, xii, 256-7 Horned Toad, xii, 204, 206 Horner, William, x, 116 Horn Gaps, vii, 17-18 Horns, in cattle family, xii, 324-5, 328; of deer, 316 Horns (musical), from shells, xii, 74; origin of, xv, 317; sound production by, iv, 239-41 Horrocks, Jeremiah, ii, 58 Horseback Riding, as exercise, x, 304, 317 Horsechestnut Tree, dense shade, xiii, 86; in landscaping, 271-2; leaf-bud protection, 34; stipules absent, 34 Horse Latitudes, i, 129, 374, xiv, 349 Horsepower, defined, iv, 80, vi, 83, 84, vii, 369; electrical equivalent, vi, 84-5; erg and calorie equivalents, vii, 382; men's labor in, iv, 311; thermal equivalents, v, 350-1 Horsepower-hours, iv, 80 Horseradish, aconite and, xiii, 252; in mustard family, 197; origin, 223 Horses, xii, 306-7; automobiles and, v, 215; class of, xii, 300; cost of work, vii, 224-6; diphtheria antitoxin from, x, 297; domestication of, xv, 197; ear movements, of, ix, 82, 117; fear in, xi, 136; geological history, iii, 299-300; pictured in ancient art, xv, 112, 114, 116; surra disease of, x, 168; young of, ix, 346 Horseshoe Magnets, iv, 250, vi, 34, 45, 333 Horsetail Plants, iii, 251, 254, 256, xiii, 308-9, 314, 317, 323 Hoses, force, vi, 47-9; rate of flow, 70-1 Hospitals, disease germs of, i, 325-6; rise of modern, xvi, 184; "Sunday temperatures" in, xi, 140 Hospital Tanks, v, 120 Hot Air Heating System, iv, 185 Hot Baths, ix, 322, x, 311-12, 383; after eating, ix, 313; cold sensation on entering, 93; therapeutic uses of, x, 311, 383 Hot Climates, clothing for, x, 307, 308; oiling of skin in, 311 Hot Springs, occurrence and explanation, iii, 128, xiv, 143-5; plant life in, xiii, 299; proof of earth's internal heat, xiv, 12; travertine deposits, 146 Hottentots, hair of, xv, 38; marriage by purchase among, 284 Hot-water Bottle, iv, 162-3 Hot Water Heating System, iv, 185-6, 187 Hot Water Plants, xiii, 299, 300, 301 Hot Waves, i, 374 Hot Winds, i, 134, 374 Hotchkiss Machine Gun, v, 365 Hotels, color lighting, vi, 274-5 House-breaking, of children, xi, 251-2 House Meters, vii, 174-7 Houses, dry air of, xiv, 353; electric wiring, vii, 65-8; evolution of, xv, 266-8 Howard, Luke, i, 97-8 Howe, Elias, sewing machine, v, 284, 379 Howitzers, v, 368-9 Huanacos, xii, 313 Huckleberry, growth of, x, 229 Hudson River, course, iii, 234, 245; estuary of, xiv, 40; locating rock under, v, 263-4; mouth, xiv, 25, 270; Palisades (see Palisades of Hudson); sediment in channel, 268; submerged channel, iii, 37 (fig.), 78, 234, xiv, 25, 287; superimposed stream, iii, 233 Hudson River Valley, drowned character, iii, 38, 77-8, xiv, 25, 40, 255; origin, iii, 232; section of, 138 (fig.) Hue, of colors, xi, 90 Hughes, D. E., vi, 26; coherer of, xvi, 191 Human Energy, consumption in life processes and work, viii, 367; daily expenditure in calories, ix, 297; efficiency in use of, 296, 306; food sources and requirements, viii, 334, 349, 350, 359, 361, ix, 289-301; from foods, calculation of, x, 269-70; per cent used, xi, 264; Ostwald's imperative, 257; production in kinetic system, 60-1 Humanists, "medical," x, 45 Human Life, temperate zones most favorable, xi, 51; temperature limits, v, 348, ii, 243 (see also Life) Human Race, cradle of, xvi, 46-7; grouping tendency of, x, 9; improvement by selection, xvi, 157 Humanistic Period, xvi, 86 Human Voice, range of, ix, 99 (see Voice) Humboldt, Alexander von, discovery of orchid insect, xiii, 48; geological work, xvi, 170, 171; on the Ghor of Syria, xiv, 121; on thunder at sea, i, 193; studies of electric eel, vi, 16 Humboldt Current, xiv, 305 Humboldt Range, iii, 214 Humidifying Systems, i, 78 Humidity, i, 76, xiv, 353-4; absolute and relative, i, 76-7, 375, xiv, 352-3, 354; atmospheric, viii, 67; body heat and, i, 317, v, 348-9, ix, 316, 317, x, 237, 251, xiv, 354; danger in thunderstorms, i, 156; heat prostration from, ix, 316; measurement of, i, 78-9; practical importance, 77-8; ventilation and, 321, viii, 331, 332, ix, 268-9, 270, x, 237 Hummingbirds, xii, 269; colors of, 245; family of, 267; plant fertilization by, xiii, 144 Humor, psychology of, xi, 350-7 Humoral Doctrine, x, 21, 28-9, 69, 98, 380 Humped Cattle, xii, 330 Humphreys, Dr. W. J., i, 58, 59, 113, 152, 153, 155, 172 Humus, formation of, viii, 340, 341, 346-7 Hungary, loess deposits, xiv, 72; plains of, xiii, 373, xiv, 217; stone implements of ancient, xv, 109 Hunger, "best sauce," ix, 242; food regulation by, 299; impulse of, in civilization, xv, 185-204, 273; sensation of, ix, 87-8, 231, xi, 65-6, 67, xv, 65; sense of, in infants, ix, 349-50; sleep and, xi, 290 Hunger Strikes, water in, x, 275 Hunt, T. Sterry, xvi, 190 Hunter, John, x, 93-6, 97; electric eel studies, vi, 16; Jenner pupil of, x, 94, 99; Virchow compared to, 129 Hunter, William, x, 92-3, 94 Hunter's Moon, ii, 196 Hunting, primitive methods and devices, xv, 222-8 Hunting Dog, African, xii, 345 Hunting Dogs, heart in, x, 332 Hunting Stage, xv, 187, 192-6; equality of members in, 376; leaders in, 366; polygamy in, 287 Hurdy-Gurdy Wheel, v, 77 Huron, Lake, size, xiv, 204 Hurricane Cliffs, xiv, 124 Hurricane Grass, xiii, 344 Hurricanes, i, 136, 375; electrification by, vii, 212-13; handling of ships in, i, 277-8; warnings in Caribbean Sea, 282, 309 Hurry, modern spirit of, xv, 12 Hussey, Obed, v, 244-5, 246, 247, 249, 379 Hutton, Dr. James, geologist, xvi, 126, 169-70 Huxley, gorilla studies of, xv, 57; on herring, xii, 156; work of, x, 136, xvi, 140-1, 142, 182 Huygens, as astrologer, ii, 21; Kepler's Laws and, 61; light theory, xvi, 119; mechanical method of, iv, 11; micrometer invention, ii, 58; on planetary pull, 63; on rings of Saturn, 54, 57; pendulum clock invention, v, 65; studies of Mars, ii, 227, 228; studies of nebulæ, 357; telescopes, 13, 57, 99 Hyacinth, xiii, 120, 184 Hyacinth Stone, iii, 341 Hyades, ii, 341-3 Hyalite, iii, 335 Hybrids, defined, ix, 334, xiii, 147; transmission of characters, ix, 334-7, x, 231-2, 233, xiii, 332, 333 Hydra, fresh water, xii, 33-4 Hydraulic Jets, v, 88 (see Water Jets) Hydraulic Machinery, v, 97-108 (see also special heads, as Cranes, Elevators, etc.) Hydraulic Press, v, 97-100, 376; mechanical gain in, iv, 41 Hydraulic Ram, v, 84-6 Hydriodic Acid, formation of, viii, 95-6 Hydro-acids, viii, 98, 114, 377 Hydrocarbons, and derivatives, viii, 51-2, 205-40; molecular complexity and physical state, 298; oxygen affinity for, 36; substitution phenomena, xvi, 162 Hydrochloric Acid, viii, 86-7, 115; action on cellulose, 255; in gastric juice, x, 320, 325, ix, 234-5, 236, 237-8; metal tests by, viii, 288; production, 87, 105, 275, 277; solubility in water, 111; test for, 285 Hydroelectric Plants, v, 79, 83, vi, 351-2, 361-78; on farms, vii, 233-4; use of alternators, vi, 215; (see also Power Plants) Hydroelectric Power, called "white coal," v, 76; in Switzerland, xiv, 242 Hydrogen, viii, 18, 29-33; affinity strength, 128; affinity for halogens, 85, 86; atmospheric, i, 11, 192, ii, 232; atomic weight and symbol, viii, 383; atomic weights based on, 33, 92; basic element, Prout's hypothesis, 177; boiling and freezing points, iv, 173; compressibility and volume, 143; critical temperature and pressure, 173; density of, 110, 113; diffusibility of, viii, 108; discovery, xvi, 120; elimination from body, viii, 353; explosions of, 33, 62; flame of, 57, 58, 59-60; increasing demand for, vii, 321; in acids, viii, 114; in organic compounds, 64, 204; in plants, 336-7, 340-1; in proteins, 351; in water, weight and volume, 39-40; liquefaction of, iv, 171, 191; melting point, 162; molecular speed, viii, 24, iv, 133; percentage in coal series, iii, 345; plant uses and sources, xiv, 64-5; positive ionization, viii, 122; preparation, 30-3, 102; sound speed in, i, 192; uniqueness of, viii, 182-3; use of, in balloons, iv, 108; valence basis, viii, 93; valences to, 178, 179-80; weight, iv, 110 Hydrogen Compounds, viii, 29, 36, 41, 51-2, 68-70, 205-40 Hydrogen Cycle, viii, 334, 350 Hydrogen Peroxide, viii, 41, 97; bleaching by, 86, 256 Hydrogen Sulphide, viii, 77-8; in metal tests, 288; solubility in water, 111 Hydrogenation, viii, 232, 247, 377 Hydroids, xii, 18, 23, 33-7; regeneration in, 170 Hydrology, problems, vi, 365-7 Hydrolysis, viii, 39, 217-18, 377; by enzymes, 357, 358; in cement setting, 280; ionization and, 120 Hydrometers, iv, 113, vi, 147 Hydrophobia, Pasteur's work on, x, 142-3; reduction of mortality in, 217 Hydroplanes, v, 192; of submarines, 197-8 Hydrostatic Pressure, v, 95-6 Hydrotherapy, x, 383 Hydroxides, viii, 93, 377; bases as, 115; commercial preparation, of, 276; metals found as, 130, 131, 198 Hydroxyl Derivatives, viii, 210, 212-14, 215, 218 Hydroxyl Group, viii, 377; in bases, 115; boiling point raised by, 299; negative ionization, 122; solubility, 112 Hyenas, xii, 351-2 Hygiene, among early Jews, x, 15; daily applications, xvi, 15; instruction in, remarks on, x, 282-5; mental, xi, 368-82; personal, disease prevention through, x, 302-17 Hygrometers, i, 78-9, 375; invention, 68-9 Hygroscope, i, 375 Hymenoptera, xii, 124-6 Hyperfunction, defined, x, 348 Hyperopia, ix, 113 Hypersensibility, x, 212-15 Hypnotism, xi, 311-22; use in medicine, xvi, 185-6 Hypo, of photography, viii, 140, 172 Hypofunction, meaning, x, 348 Hypophysis, (gland), x, 347, 352 Hysteresis, vi, 192, 213-14; in motors, 225; in transformers, 316 Hysteria, x, 360-3 Ianthena, xii, 19 Iatrochemical School, x, 69-70 Iatrophysical School, x, 69, 70-2 Iberian Racial Group, xvi, 49 Ibervillea, xiii, 106-7 Ibexes, xii, 325-6 Ibises, xii, 254, 255-6 Ibn-Yunos (Jounis), ii, 38, 210 Ice, ancient use in refrigeration, v, 349; artificial, iv, 188, v, 349-50, 354-8, viii, 69-70; color of, 40; comparative heat, v, 345; cooling by, iv, 178, v, 346; density of, iv, 149; disadvantages in refrigeration, vii, 230; erosion by, (see Glaciers); expansion of water in, viii, 38; heat conductivity, iv, 179; keeping of, v, 346, 349; melting point and requirements, iv, 152, 161, 162; melting point, pressure effects on, 163, 164, 164-6; mixture with salt, temperature resulting, 175; mixture with water, temperatures obtained, 160-1, v, 353-4; regelation of, iv, 164-6; specific gravity, iii, 321; specific heat of, iv, 155; temperatures at different pressures, v, 345; transformation of snow into, iii, 59-60; warming of, iv, 151-2 Ice Age, Great Quaternary, iii, 236-48, xv, 72-6; antiquity of, xiii, 209, 322; lakes formed, iii, 143-51; man during, 302, 303, xv, 102; Mississippi Valley remains, iii, 35; moraines left by, 67-8; sea level in, 83; subsidence of land in, 80; Yosemite Valley formed in, 48, 64 (see also Glacial Epoch) Ice Age, Permian, iii, 203-4 Ice Ages, theories of, iii, 247-8; volcanic dust theory, i, 58 Icebergs, submergence of, iv, 149 Ice Breakers, gyroscopes on, v, 342 Ice Caps, iii, 60, 61; of Greenland and Antarctica, xiv, 55 Ice Clouds, i, 92-3, 103; halos produced by, 177 Ice Dam Lakes, iii, 143-4, xiv, 201 Ice Crystals, i, 115-16; halos from, 177, 178, 182-3 Ice Fogs, i, 95-6 Ice Houses, insulation method in, iv, 178 Iceland, discovery and settlement, xiv, 261; fault displacement in, 39; foxes of, xii, 344; future manufacturing center, v, 173; ice caps, iii, 61; low pressure area, i, 361; volcanic eruptions, 57, 59; volcanic formation, xiv, 277, 289, 316 Icelandic Language, xv, 162 Iceland Spar, iii, 325; effect on light, 319, iv, 354 Ice Needles, i, 92-3, 96 "Ice Pavement," xiv, 56 Ice Rain, i, 107, 375 Ice Saints, i, 363, 375 Ice Sheets, iii, 60, 61-2; of Great Ice Age, 237-42, xv, 74-6 Ice Storms, i, 108 Ice Water, drinking of, ix, 229; temperature of, viii, 38 Ichneumon Flies, xii, 125 Ichneumons, xii, 352 Ichthyornis, xii, 243 Ichthyosaurs, iii, 286-8, xii, 182, 202 Idaho, lava formations, xiv, 102, 103, 318; mining products, iii, 362-3, 368 Idaho Fire (1910), i, 57 Ideal Metal, resistance, vi, 77 Ideas, psychological meaning, xi, 201-2 (see also Association of Ideas, Dissociation, Repression) I-em-hetep, x, 11 Igneous Rocks, iii, 13, 379, xiv, 17-18; common modes of occurrence, iii, 102 (fig.); illustrations (Pl. 8, 9, 10); intrusive and extrusive, xiv, 105; intrusions in mountain ranges, 228, 230, 232-3, 234; jointing in, 129-30; land forms in, 44, 99-113; oldest by nebular theory, iii, 160; soils from, 28; volcanic and plutonic, 106, 110, xiv, 99-100 Ignis Fatuus, i, 346-9, 375 Ignition, electric, vii, 369; in automobiles, 130-41, 369; in firearms, viii, 145; temperatures of, 53-4 Iguanas, xii, 207; boas and, 216; color of, 204; spiny crest of, 204 Ilkhanic Tables, ii, 39 Illinois, coal beds, iii, 199; prairies of, xiv, 373, 383 Illinois River, sewage effects, viii, 326 Illuminating Gas, acetylene, viii, 60, 231; burning of air in, 55, 56; flame of, 57-9; production, 46, 47, 252; requisites, 60; transfusion of blood in, poisoning from, x, 338 (see also Gas Lighting) Illumination, art of, vi, 273; measurement of, iv, 350-2; unit of intensity, vii, 368 (see also Lighting, Lighting Systems) Illusions, x, 358 (see also Hallucinations) Illusions, Optical (see Optical Illusions) Ilopango, Lake, draining of, xiv, 198 Images, formed by reflection, iv, 335-7; formed by refraction, 337-9; formation of, ix, 106-9; real and virtual, iv, 335, 338, 339 Images (psychology), xi, 218-22 (see also After-Images) Imagination, xi, 218-27; due to conditioned reflexes, 202-3; in science, xvi, 58-9 Imbeciles, reflex action in, xi, 36 Imhoff Tanks, viii, 328 Imitation, education by, xv, 66-7; in language, 153-4; instinct of, xi, 56; suggestion and, 304 Immunity, against disease, ix, 179, x, 204-12; racial, xv, 48-52 Impedance, in alternating currents, vi, 170, 171; in oscillating circuits, vii, 289 "Imponderables," iv, 47 Impressions, first, xi, 211-12 Impulsiveness, of motor type men, xi, 157, 158-9; will and, 264 Inanition, x, 275-7, 279 Inattention, xi, 25, 236 Inbreeding, in plants, xiii, 119-20 Incandescent Bodies, spectra of, ii, 112-13, iv, 360-3 Incandescent Lights, iv, 311 Incas of Peru, civilization in temperate climate, xv, 123; corn in tombs, xiii, 212; hunts of, xv, 222; quipus of, 165, 166, (fig.) Inclined Plane, iv, 90, v, 35-41; primitive use of, iv, 24 Index of Refraction, in chemical analysis, viii, 310 Index Plants, i, 255 India, aborigines in black race, xv, 37; aconite used as poison, xiii, 252; adjutant bird of, xii, 255; aerial photographic service, i, 46; ancient astronomy, ii, 25, 26, xvi, 57; ancient meteorology, i, 68, 213; ancient science, xvi, 54, 62; ancient sun-worship, ii, 23-4; animals (carnivora), xii, 337, 340, 344, 345, 359, 365; animals (herbivoral), 302, 303, 305, 308, 320, 327, 328, 330; artificial ice in ancient, v, 349; banana plants, xiii, 216; betel nut, 254; brontides, i, 195; bubonic plague in, x, 164, 165; Catalan forges in, v, 315; cinnamon growing, xiii, 264; civilization and climate, xv, 123; coco palm of, 125; copra production, xiii, 220; cotton production, 237, 238; cradle of human race, xvi, 47; crocodiles of, xii, 199, 201; deer-hunting in, 365, xv, 223; dust whirlwinds, i, 60; earthquake of, xiv, 333 (see Great Indian Earthquake); famines, xiii, 214; forests, government-controlled, 372; former trade routes, xiv, 307, 309; glacial deposits, iii, 203; hailstorms, i, 120; Himalayas as protection to, xv, 137; ideas of eclipses, ii, 209; jungle fowls of, xii, 261; jute production, xiii, 241, 243; monkeys of, xii, 379; monsoons, importance, i, 66-7, 131, 218, xiv, 350-1; monuments and records, ii, 24; music of, xv, 314 native marriage customs, 282; peoples and civilization, xvi, 53-4; pipal tree, xiii, 108; plains of, xiv, 47, 217; polyandry in, xv, 286; poppy growing, xiii, 253; quinine production, 251; rainy seasons, xiv, 352; rattan palm, xiii, 27, 361; religious cults, ix, 266; religious philosophy, xi, 116; rice in, xiii, 213; rivers of, xiv, 195-6; rubber growing, xiii, 247, 248; serpents of, xii, 214, 219, 228-9, 231; smallpox inoculation in, x, 100; sugar production, xiii, 215; Suttee in, xv, 335; tarpon of, xii, 154; tea cultivation, xiii, 228; telegraph plant, 114; tobacco production, 258; tortoises of, xii, 191; weather conditions, distant causes, i, 241; wine palm, xiii, 53 (see also Hindus) Indiana, glacial drift in, xiv, 69, 170; limestone quarries, iii, 371-2; prairies of, xiv, 373 Indian Corn, American origin, xiv, 382; history and uses, xiii, 211-13; prop roots, 20 (fig.); stem, 183 (see also Corn) Indian Meteorological Dept., i, 241 Indian Ocean, extent of, xiv, 22; monsoons of, 350-1; salt in, viii, 139; sharks of, xii, 146; tortoises on islands of, 192 Indian Pipe Plant, xiii, 99, 202 Indians, American, acuteness of vision, vi, 272-3; arrows of, xv, 196 (fig.); basket-weaving of, 248; bows of, 214 (fig.); canoe-making, 262; cattle-raising stage absent, 187, 199; chiefs, 364; color of, 37; corn-growing, xiii, 211-12, 212-13, xv, 201 (fig.); dogs used in hunting, 223; domestic animals lacking to, 199; dramatic ceremonies and plays of, 305-6, 306-7, 308; fear of pogonip, i, 96; fertilizing method of, xv, 202; guardian spirits, 348-9; hair of, 37; Happy Hunting Grounds of, 333; "hiqua" money of, xii, 74; language deficiencies, xv, 144; lodgepoles of, xiv, 374; long houses of, xv, 267; marriage practices, 283-4, 284; measles and, 48; mineral springs used by, xiv, 145; note to Jenner, x, 103; painting of faces by, xv, 256; pottery of, 250 (fig.), 252 (fig.); prairie firing, xiii, 374; prayers of, xv, 346-7; religious beliefs, xvi, 44; signal fires, xv, 165-6; sign language, 148-51; sign writing, 172, 173 (fig.); stone pestles of, 238 (fig.); tents of, 266; tomahawks of, 208; tree-felling by, 262; tribal morality of, 374; tribes in mountains, 129-30; unions among, 363; weaving of, 247 (fig.), 301 (fig.) (see also South American Indians) Indian Summer, i, 361-2, 363, 375 India-rubber, elasticity of, iv, 36; low temperature effects, i, 31 Indicators, chemical, viii, 114, 294, 378 Indigestion, causes and results, ix, 238-42; from worry, 165, 167; mental effects, xi, 369-70 Indigo (color), ix, 115; changed to indigo white, viii, 259 Indirect Lighting, vi, 277, vii, 70 Indium, symbol and atomic weight, viii, 383 Individuals, differences in, ix, 327, xi, 152-9; influence of, in history, 333; inheritance of extreme characters, xvi, 154; moral control, 48; new species from variations of, xiii, 325, 328-9; psychology in crowds, xi, 324, 325-30; transmission of acquired characters, ix, 325-6 Indo-China, food plant source, xiii, 221; python of, xii, 214 Indo-Chinese, in yellow race, xv, 37 Indo-European Languages, xv, 161, 162 Induced Currents, iv, 303-9 Induced Voltages, vii, 370 Inductance, defined, vi, 91, 166; in direct and alternating currents, 166-7, 169; flashes caused by, 102, 312; in induction motors, 248; in telephone lines, vii, 104; in wireless communication, 264, 286-7, 289, 293-5, 296-7 Inductance Coils, vii, 105, 264, 266, 267 Induction, charging by, vi, 290-2, 297-301; discovery, 22, 23; electrification by, iv, 260; electrodynamic and static, vii, 370; law of, vi, 313; Lenz's Law, vii, 371; magnetization by, iv, 243; self, vii, 375; unit of, iv, 285 Induction, Proof by, xi, 242 Induction Coils, iv, 265, 303-5, vii, 364, 370; in automobiles, 133-4; in electrotherapy, 242-4, 245; in wireless telegraphy, iv, 313, 314 Induction Machines, vi, 292, 298-301, vii, 245 Induction Motors, vi, 241, 242-56; in motor-generator sets, 332, 342 Induction Regulators, vi, 328-9, 346 Inductivity, vi, 293-4 Industrial Plants, advantages of electricity, vii, 51-3; lighting, 52; wiring, 57 Industrial Psychology, xi, 358-67 Industry, electricity in, vi, 195-6, 381; energy sources, viii, 267-8; metals of, 154; motors most used, vi, 241; science in, xvi, 9-10; water power and, vi, 352 Inertia, defined, vi, 90-1, vii, 370; examples of, iv, 35, 62, 66, 67, v, 148, 234, 336-9; in electrical currents (see Inductance); in perception errors, xi, 184, 189; law of, ii, 62, iv, 19-20, 61-2; of æther, vi, 120; of ear, xi, 105; of sense organs, 71 Infancy, period of, x, 283, xvi, 79 Infantile Paralysis, germ of, x, 200, 202; immunity to, 207 Infants, ape-like structures in, xv, 61; bodily condition and care of, ix, 345-52; clothing of, x, 309; grasping reflex, xi, 40-3; heart rate in, x, 334; learning to breathe, xi, 36-7; learning to fixate, 39-40; learning to swallow, 38; milk modifications, viii, 363; nervous system in, ix, 344, 348-9; new-born, free from germs, x, 201; new-born, weight of, ix, 31; periodic breathing in, x, 340; skull capacity in, xv, 40; space perceptions, xi, 162-3, 166 Infections, ix, 177-8, x, 193; by germs, x, 193, 204; body resistance to, 197-8, 203-12; body resistance to, ix, 177-9, 185-6; exhaustion from, ix, 59-60; focal, x, 198-9, 218-26; in surgery, prevention of, 14, 123, 145-7, 181-3; local and general, 198; "portals" of, 198, 201-2; pus, ix, 186-8 Infectious Diseases, x, 193-226; atmospheric electricity and, i, 330; danger from, 326; heredity and, x, 234-5; immunity to, 204-12, ix, 179; infants' susceptibility to, ix, 352; pain in, 87; Pasteur and Koch's work, xvi, 184; prevention and treatment, x, 217-18, 285-302 (see also Antitoxins, Inoculation, Vaccination); ticks as cause of, xii, 98; transmission and history of various, x, 153-70 Infinity, meaning, xi, 191, 196 Inflammations, germ-produced, x, 195; terms used to define, 30 Influence Machines, vi, 292, 298-301, vii, 372; in therapeutics, 236 Influenza, x, 294-5; from chilling, 306; immunity to, 207; present knowledge of, 153, xv, 48 Infra-red Rays, iv, 365, 366 Ingersoll, Dr. E., author Zoölogy, Vol. xii Ingots, steel, v, 322; "pipes" in, 323 Injections, subcutaneous, ix, 59 Injectors, of boilers, v, 140-2, 380 Ink, Acheson's, vii, 301 Innominate Bone, ix, 63 (fig.), 66-7 Inoculation, early practice of, x, 207; for anthrax and rabies, 141-2; for smallpox, 100-3 (see also Vaccination) Inorganic, defined, viii, 378 Inorganic Chemical Industries, viii, 267-84 Inorganic Compounds, colors of, viii, 312; solubility in water, 37, 111-12 Inorganic Matter, plant use of, viii, 339, 349, xiii, 14, 79, 81 Inorganic Nature, chemical inactivity, viii, 267 Insanity, definition and symptoms, x, 357-9; former ideas and treatment, 11, 356-7; increase of, xv, 27; increase prevention, x, 235-6; Pinel's treatment, 110-11; primitive conceptions of, xv, 350, 353 Insecticides, arsenic, viii, 169 Insectivora, xii, 366-8; lemurs and, 376 Insects, xii, 99-126; capture of, by plants, xiii, 39-41; classification, iii, 260, 276; cold effects on, ix, 306; evolution, iii, 20, 257, 279, xii, 104-7; flower fertilization by, xiii, 48, 123-46, 318, xvi, 152-3; fossil remains, iii, 16, 279-80; hearing of sounds by, iv, 204; jaws in, xii, 106; larvæ affected by light, x, 253; musical, xii, 109-10; number of species, 99; popular definition, 90; primitive groups, 104-7; protective coloration in, xv, 17-18; reproduction in, xii, 104; respiration in, 103; structure of, 99-103; studies of, xvi, 143-4; tool-using by, v, 10-11 Inside Passage, xiv, 258-9 Insomnia, xi, 288-91; caused by vasoconstrictor activity, ix, 218-19; exhaustion from, xi, 59-60 Inspiration, as intuition, xi, 245; Titchener on, 226 Instincts, defined, xi, 46-8; fundamental, 49-56, xv, 185; in man and animals, 65-6; reflex nature, xi, 48-9; self-preserving, x, 9-10, 282-3 Instrument-Shelter, i, 375 Instrument Transformers, vii, 44, 165 Insular Climate, xiv, 347 Insulation, importance, vi, 9-10; in dynamos, 192, 211-12; types of wire, vii, 58 Insulators, electrical, iv, 259, vi, 294-5, vii, 370; pin and suspension types, 15-16 Insulators, heat, iv, 178, vii, 307-8 Insults, emotions from, xi, 150 Insurance, weather, i, 269-70, 344 Intake-Output Test, x, 379 Intellectual Processes, in brain, ix, 147-53, 154 Intelligence, artificial selection of, xvi, 154; mental economy and, xi, 377; instinct and, 46, 47, 50; nervous organization and, 13 Intelligence Tests, xi, 359-60 Intemperance, arteries injured by, ix, 214 Intensity, electric, vii, 370 Intensity, of sounds, iv, 211 Interborough Rapid Transit Company, great alternators, vi, 216, 378-9; synchronized plants, 384 Interchangeable System, v, 48-52, 53-4, 55-6 Interest, advertising value, xi, 345-6; associations determined by, 203, 205-6; attention and, 235-6; fatigue and, 275; in salesmanship, 341-2 Interference of Light, iv, 376-8 Interference of Sounds, iv, 218-22 Interferometer, ii, 151, 323 Interior Lighting Systems, vi, 275-8, vii, 68-72 Interior Wiring, vii, 51-72; insulators in, 370 Interlaken, Switzerland, lakes at, xiv, 202 Internal Combustion Engines, v, 155-70; in aeroplanes, 231; in automobiles, 213; in submarines, 199; efficiency, securing of, xvi, 135; Joule's equivalent and, 132-3 Internal Senses, ix, 86-91 Interoceptive Senses, xi, 63 Interpoles, of dynamos, vi, 190-1 Interurban Traction, vii, 181; automatic substations, 192-3; cars and motors, 186; voltage drop, 189 Intestinal Stasis, x, 220 Intestines, ix, 233 (fig.); development in black and white races, xv, 50; emotion effects on, xi, 135, 137; functions of, viii, 356-7, 358; functions, operations, and disorders of, ix, 232-4, 236-8, 242-52, x, 325-9; germs in, ix, 247-9, x, 193, 194, 201, 287-8; infections through, x, 198, 220, 221; in infants, ix, 346; inflammation of, cause, x, 224; length in animals and man, ix, 246; mucous membrane, functions of, x, 347; position in circulatory system, ix, 196 (fig.), 198; smooth muscles in, 74, 160-1, 162 Intrenched Meanders, xiv, 165 Intrusive Rocks, xiv, 105 Intrusive Sheets (sills), xiv, 108 Intuition, xi, 245-6; Bergson on, xvi, 196 Inventions, imagination in, xvi, 59; inspiration and labor in, xi, 226; method of great, xvi, 98; misuse of ancient, v, 15-16, 111; necessity and laziness in, 282; production increased by, 17-18; pure science preliminary to, iv, 44-5; summary of mechanical, v, 376-84; war as stimulus to, 12, 359-60, 375 Inverse Time Relays and Switches, vii, 37, 39-40, 41, 42 Invertases, viii, 357 Invertebrates, xii, 127; age of, iii, 20; largest, xii, 80 Invincible Armada, xiv, 280 Inyo Earthquake, iii, 225 Iodine, a halogen, viii, 18, 84-5, 86; as antiseptic, 333; atomic weight and symbol, 383; classification place, 182, 183; indicator uses, 294; in seaweed, 197; manufacture of, 274; physical state and, chemical properties, 22, 297-8; test of, 290; thyroid secretion of, x, 351 Iodoform, viii, 52, 212 Ion-Counters, i, 142-3, 375 Ionic Reactions, viii, 119-25 Ionization, vi, 133-5, vii, 247, 248, 370; defined, viii, 378; electron theory, 188; in electric precipitation, vii, 348-9; of atmosphere, i, 142-4, 146, 150; of solutions, viii, 119-25, 300-1; origin of theory, 296, 300-1 Ionogens, viii, 122, 125, 378 Ions, iv, 382, vii, 370, viii, 378; in electric batteries, vi, 133, vii, 247; number in air, i, 142-3; of solutions, viii, 120-4, 286-90; origin of name, 124; positive and negative, i, 142, vii, 247, 370 Iowa, glacial deposits, iii, 241; gypsum deposits, 376; loess deposits, xiv, 72; porous rocks beneath, iii, 114; soil of, xiv, 383; wells, iii, 118, 119, 125 Ireland, Alpine invasion, xvi, 49; coast formations, xiv, 24, 47, 249, 251, 257; continental island in character, 273; "Emerald Isle," 352; eskers and drumlins, 59, 60; former volcanoes, 318; Ice Age in, xv, 74; lakes of, xiv, 200; lava plateau of, 104; potato in, xiii, 218; rainfall in, xiv, 41, 352; scurvy and potato crop, x, 266; snakes in, xii, 217 Iridescence, cause of, xii, 245 Iridium, viii, 173, 383 Iridocytes, xii, 135 Iris, xiii, 22-3, 57 (fig.) Iris Family, xiii, 189 Irish, pre-Nordic, xvi, 49 Irish Language, xv, 162 Irish Potato, xiii, 218, 219 Irish School, of Medicine, x, 112 Irish Wakes, xv, 336 Iron, affinity strength, viii, 128; antiquity of use, v, 314-15; atomic weight of, viii, 180, 383; body use of, ix, 184, x, 256; cast and wrought, v, 316-17; cast and wrought, viii, 157, 158, 159; castings of, iv, 150; density of, 111; electrical conductivity, 283, vi, 77; electrical positiveness, 59; electrolytic refining, vii, 320; expansion on solidifying, iv, 150; expansion rate, 145-6; extraction from ores, viii, 271; fusibility, 384; galvanized, vii, 318-19, viii, 155-6, 273; heat conduction by, iv, 179; importance, v, 314, viii, 156; in blood, 354; in chlorophyll, xiii, 79-80; in earth's crust, iii, 308, viii, 19, 129, 192; in earth's interior, xiv, 11; magnetic, iv, 242, 243 (fig.); magnetization, 243, 245, 251, 287-8, vi, 35-6; melting point and requirements, iv, 162, 163; metallography of, viii, 273-4; meteoric, ii, 292; meteoric, in deep sea, iii, 55; ores and occurrence, 355-9, viii, 47, 130, 148, 156, 198; ores, profitable, 197; plant needs of, 337, 341; properties of, 126-7, 154; rusting, iii, 25, viii, 9, 13, 155-6; sheet tin, 161; shortness, hot and cold, iii, 356; sound velocity in, iv, 201; specific gravity of, 109, viii, 384; specific heat, 308; symbol, 383; test for, 287, 288-9; valences, 161, 189 Iron Age, xvi, 51; tools of, 47 Iron Compounds, viii, 160-1 Iron Industry, history, xvi, 174-6; processes in, v, 315-18, viii, 157-9, 273, 345 Ironing Machines, Electric, vii, 82-3 Iron Oxides, viii, 13, 156, 157; in pigments, 265; in rock decay, iii, 25, 27; in soils, iii, 28; removal in steel-making, v, 320; rock coloring due to, iii, 25-6, 27, 44 Iron Pyrites, iii, 335, viii, 156, 198; in wireless detectors, vii, 269 Irons, Electric, vii, 77 Iron Ships, floating of, iv, 104-5; magnetization of, 254 Iron Structures, magnetization of, iv, 253 Iroquois, Lake, iii, 149, 150 Iroquois Indians, and Mohawk Valley, xiv, 194; power of women among, xv, 295; union in nation, 363 Irrationality of Dispersion, ii, 101 Irrigation, development of methods, v, 239; in Egypt, 18-19, 178; electrical methods, vii, 231; in relation to critical periods, i, 250; sewage disposal by, viii, 327; snow sources, i, 118 Irritability (life), doctrine of, x, 86, 87, 88 Isallobars, i, 238 Ischia Earthquake, xiv, 339 Isinglass, iii, 334 Islands, classes, continental and oceanic, xiv, 271-9; formed on coasts, 251-2, 256, 258; historical importance, 281-2, xv, 137; new volcanic, xiv, 319; overpopulation of, 282; plants of oceanic, xiii, 348; tidal races produced by coastal, xiv, 294 Isobaric Elements, viii, 189 Isobars, i, 125, 375-6; classification, 238; spacing, 126; winds in relation to, 126 Isohyet, defined, i, 376 Isohyetal Charts, i, 206 Isomer, defined, x, 137 Isomerism, defined, viii, 378 Isomorphism, viii, 313 Isothermal, defined, iv, 382 Isothermal Changes, in gases, iv, 156, 159 Isothermal Layer (atmosphere), i, 19 Isotherms, i, 206, 207, 376; barriers to plants and animals, xiv, 364 Isotopic Elements, viii, 189 Israelites, "Cities of Refuge," xv, 369; life of, 199 Italian Honeysuckle, xiii, 142-3 Italian Language, descent from Latin, xv, 160, 162; musical terms from, 161 Italians, in Alpine group, xvi, 49 Italy, Adriatic coast, xiv, 252, 263; aeronautical weather service, i, 230, 304; Alps Mountains and, xiv, 244-5, xv, 138; "blood showers," i, 55; boric acid sources, viii, 90; brontides, i, 196; bubonic plague measures, x, 164; buffalo use in, xii, 329; earthquakes of, xiv, 332, 340-1; former connection with Tunis, 291; geographical changes in, 33; hail-shooting, i, 341, 342, 343; lakes, beauty of, xiv, 200; lakes, breezes of, i, 132; mercury production, iii, 370; meteorological observations, i, 68-9, 213; Napoleon's campaigns in, xiv, 244; paper-making, v, 290; rainfall, xiv, 358; Renaissance and science in, ii, 12-13; rice growing, xiii, 214; sea captains of, xiv, 310; volcanic power, v, 179-80; in World War, xiv, 244-5, 252-3, xv, 138; in World War, medical preparedness, x, 176 Itching, sensation of, ix, 92-3, xi, 109, 114 Ivory, elasticity of, iv, 36; sources of, xii, 302, 303 Izalco Volcano, xiv, 321, 325 Jackals, xii, 339-40; dogs and, 344; ears of, 346 Jack-in-the-Pulpit, in arum family, xiii, 188; flower, 52 (fig.); leaves, 183 (fig.); stems, 23 (fig.) Jacks, Hydraulic, v, 100, 101, 124, 260 Jackson, Dr. Charles T., x, 124, 125 Jackson, James, x, 116, xvi, 185 Jacquard Loom, v, 280-2, 377 Jade, iii, 322-3; pyroxene, 336 Jaguars, xii, 360-2 Jaguarundi, xii, 364 Jamaica Earthquake, cause, xiv, 340 James, William, on associations, xi, 204-6; on attention, 232; on emotions, 141; on habit, 255-6, 256-7; on instincts, 48; on memory, 208; on stream of consciousness, 193; on will and action, 264; on complexity of life, x, 244; on seasickness, 242; on outdoor treatment, 241; pragmatic philosophy, xvi, 196 James, W. T., link motion invention, v, 208, 379 James, I. Harvey, physician to, x, 62; of England, submarine trips, v, 196-7 James River Valley, N. D., wells in, xiv, 12, 139 Janet, Dr. P., x, 360-1 Janssen, Jules, astronomer, ii, 114, 127, 180-1; station on Mt. Blanc, 142 January Thaws, i, 363, 376 Japan, Ainus of, xvi, 64; beriberi in, ix, 35, x, 257; brown bears of, xii, 336; copper production, iii, 360; earthquakes of, xiv, 332, 341; earthquake studies in, 337, 342; geology of, 125; ginkgo tree in temples, xiii, 315; goat antelope of, xii, 325; historical development from insulation, xiv, 281; idea of eclipses in, ii, 209; octopod fishing, xii, 78; railway bridges, earthquake construction, xiv, 342; rice, xiii, 213; tea cultivation, 228; temperate rain forests, 372; tidal waves, xiv, 337; trees of, 377; volcanic eruption effects, i, 57, 59 Japan Current, xiv, 304 Japanese, artificial immunity practiced by, xv, 49; food and stature of, xiii, 172; in yellow race, xv, 37; tattooing among, xv, 258 Japanese Earthquake, iii, 94; fault formed by, xiv, 334, 335 Jasper, iii, 337 Jaundice, cause of, ix, 243; epidemic, x, 201 Java, ancient man-ape of, iii, 302, xv, 88-92; bats and fruits of, xii, 370; cinnamon production, xiii, 264; continental island, xiv, 274; tea cultivation, xiii, 228; transplanting rice in, (illus.) 208; zoölogy of, xiv, 274-5 Javelins, Roman, xv, 213 Jaws, bones and functions of, ix, 62-3; deformities of, results, 228; in aged people, 57; in apes and men, xv, 62; of primitive men, 91, 92, 95; protruding, classification by, 43-5 Jealousy, absent in polygamous countries, xv, 288; sentiment of, xi, 149-50 Jefferson, Thomas, on climatic changes, i, 201; on standard muskets, v, 49; vaccination interests, x, 102 Jelly-Fishes, iii, 259, 266-7, xii, 35-7; coelenterates, 26; phosphorescence of, 18, 19 Jenkins, C. Francis, v, 330 Jenner, Edward, x, 99-103, xvi, 126-7, 184; love affair, x, 95; pupil of John Hunter, x, 94, 99; vaccination discovery, x, 100-2, 122, 207-8 Jerboas, xii, 289-90 Jesuits, meteorological services, i, 213, 223; survey of China, xvi, 123 Jewelweed, seed dispersal, xiii, 56 Jewish Medicine, x, 15-16 Jews, of Asia and Europe, xvi, 64; circumcision, untransmitted, x, 230; history in relation to Ghor of Syria, xiv, 121; immunity from trichina, xv, 49; polygamy among, 289; prepotency in crosses, x, 230 Jew's Harp, iv, 232 Jibon River, Salvador, xiv, 198 Jihar River, xiv, 185 John Daniel, orang-utan, xvi, 25 "John H. Grindle", (fish), xii, 152 John of Gaddesden, x, 41 Johns Hopkins Hospital and Medical School, x, 151, 172 Johnson, Prof. D. W., coast classification, xiv, 253; on climatic changes, 361 Johnson, Samuel, compared with Paracelsus, x, 48; on Heberden, 104 Johnstown Flood, iii, 31 John the Baptist, locusts and honey of, xv, 134 Joints, arm and hand, ix, 67; diseases of, x, 224-5; dislocation of, ix, 71; fastening at, 70-1; hip, 67, 71; motion sense in, ix, 90; muscles to move, 76-7; sensations of, xi, 124-5, 128; shoulder, ix, 66, 71 Joints, Joint Blocks (geology), iii, 23, 379, xiv, 128-30; illustration, iii, 144 (Pl. 8); residual cores, iii, 32 (Pl. 1); topography and drainage effects, xiv, 130-3; various examples, iii, 48, 49-50, 65 Joint Worms, xii, 125 Joliet, expedition of, xiv, 192 Joplin, Mo., mining district, iii, 362, 364 Jordan Engine, v, 294-5 Jordan River, base level of, xiv, 164 Jordan Valley, iii, 151, xiv, 118, 120, 167 Jorullo, Mexico, xiv, 320 Joule, electrical energy unit, iv, 284, 294, 310, 312, vii, 370; used as heat unit, 369; erg and calorie equivalents, 382; work or energy unit, iv, 80 Joule, James Prescott, energy unit named for, iv, 284; heat experiments of, 49-50; mechanical equivalent of heat, xvi, 131-3 Joule-Thomson Effect, i, 30 Joy Stick, i, 299 Judæa, Wilderness of, xiv, 121 Judaism, development of, xv, 199 Jumping Hare, xii, 290 Juniper, a conifer, xiii, 174; in landscaping, 270; spread by buds, 340 Junker Engine, v, 163-4 Jupiter (planet), ii, 260-3; atmosphere, 249, 261; comet families, 271; disturbing effect on asteroids, 258; "great inequality," 87; habitability of moons, 250; life on, ii, 248-9; lucid planet, 249, 261; photographic studies, 132-3; rotation period, 377; satellites, 261-3; satellites, discovery of, 54, 83, 94, 110, 267; size and orbit, 162, 163; weight, 76, 77 "Jupiter", U. S. collier, vii, 326 Jura Mountains, xiv, 93-4; age of, 232; folding of, 36, 93-4, 229-30; little metamorphism in, 234; streams of, 94, 95, 157, 167 Jurassic Period, iii, 213-14; Age of Reptiles, xv, 71; animal and plant life in, iii, 20, 255, 270, 276, 289, 295; flies of, xii, 104 Juries, as crowds, xi, 326 Justifying (printing), v, 308; on linotype, 310; on monotype, 311-12 Jute, cellulose composition, viii, 254; uses and production, xiii, 241-3; economic importance, 208 Juvenile Water, xiv, 151-2 Kaaba of Mecca, ii, 284 Kaguan, Malayan, xii, 367 Kalahari Desert, xv, 133; antelopes of, xii, 327 Kames, glacial, iii, 69-70 Kayaks, xv, 264 (fig.) Kangaroo Mice, xii, 290 Kangaroos, xii, 278-80; young of, 274 Kansas, ancient birds of, xii, 242; former reptiles of, 202; gypsum deposits, iii, 376; locust plague of, xii, 109; volcanic dust beds, xiv, 327 Kansas City, automatic telephony, vii, 92 Kant, excessive professionalism of, xi, 376; nebular hypothesis, ii, 367-8, 380; on structure of universe, 350, 352; philosophy of, xvi, 111 Kaolin, iii, 333; formed from feldspar, 25, 27, 373 Kapteyn Plan, ii, 353 Karnak, Temples of, ii, 25-6 Karst District, xiv, 150 Katathermometer, i, 319-20, 321, 376 Katmai, Mount, crater, iii, 101 (fig.), 102; eruption, i, 59, iii, 102; lake in crater, 155 Katydids, xii, 109-10; Florida, 100 (fig.) Kaye, John, x, 45 Keewatin Glacier, iii, 238-9 Keewatin Series, iii, 169 Kelvin, Lord, contributions to electricity, vi, 23-4; on oscillatory circuits, xvi, 191; on rigidity of ether, 137; theory of life, xii, 9 Kelvin-Chetwynd Compass, vi, 41-2 Kelvin's Law, vii, 21-2 Kent's Cavern, England, xv, 77-83 Kentucky, "Blue-grass Region," xiv, 68; "dark and bloody ground" of, 243; glacial period in, 376; non-glacial topography, 56; underground streams, 149 Kentucky Blue Grass, xiii, 179 Kenya, Mount, glaciers of, xiv, 54 Keokuk Power Plant, v, 81-3, vi, 352 Kepler, Johann, ii, 14, 49-52, iv, 19, 95, xvi, 102-3; as astrologer, ii, 21; on comets, 83-4; eclipse calculations, 216; Galileo and, 53; idea of moving bodies, 63; new star seen by, 331; on star distances, 350; on sun's corona, 221; Tycho Brahe and, 12 Kepler's Laws, ii, 49-52; Newton's explanations, 62-6, 88, xvi, 115-16; proved by Keeler's discoveries, ii, 121; used in weighing planets, 75-6 Kerosene, viii, 51, 208; combustion of, 52, 54, 57, 59; soap and, 142; used in mosquito campaign, x, 300 Ketones, viii, 225 (note) Kettle Holes, iii, 144 Keyhole Nebula, ii, 355, 365 Key Instruments, xv, 318 Kidney Diseases, atmospheric conditions best for, x, 241; blood pressure and, 335; Bright's Disease, 112, 346; from focal infections, 224, 225; nephritis, 344-5, 346; salt in, 256; therapy of, 382-3 Kidneys, development in black and white races, xv, 50; emotion effects, xi, 135; functions and disorders, x, 342-6; functions and structure, ix, 271-4; functional capacity tests, x, 377-9; position in circulatory system, ix, 51 (diagram), 197, 198, 199; Simon's removal of, x, 131; sugar handling by, ix, 291-2 Kilauea, volcano, iii, 103, 104, 105, 106-7, xiv, 322, 323 Kilimanjaro, Mount, xiv, 317 Killdeer (plover), xii, 262 Kilogram, iv, 46, viii, 28; standard, iv, 69 Kilowatt, iv, 80, 312, vi, 85, vii, 370 Kilowatt-Hour, iv, 81, vi, 82, 84; meters and charges for, vii, 174 Kinaesthetic Sensation, xi, 124-8; space perception by, 166-7, 169-70, 175, 183, 186; strain in attention, 228, 231-2; in will, 265 Kindling Temperature, viii, 54 Kinematic, defined, iv, 382 Kinetic, defined, iv, 382 Kinetic Energy, iv, 79, 81, 83; defined, v, 84, vii, 368; forms of, iv, 82-5, 87-8 Kinetic System of Body, xi, 57, 60-1; action in attention, 231-2; connection with sensation, 67, 68, 127 Kinetic Theory, iv, 30, 131; of gases, viii, 305-6, 378 Kinetics, defined, iv, 25 Kinetoscope, iv, 348, v, 330 King, Prof. L. V., i, 190-1 Kingfishers, xii, 267 King's River Canyon, iii, 43, 225 Kingston Earthquake, xiv, 340 Kiosks, weather, i, 75, 267, 376 Kipling, airship prediction, i, 43; "female of the species," x, 162; on dew ponds, i, 353 Kirchhoff, spectrum lines, ii, 17, 112-13 Kitasato, x, 164 Kitchens, lighting, vi, 276, vii, 71 Kite Balloons, v, 226 Kites, v, 230, 233-5; action of wind on, iv, 42-3, 76 (fig.); aerological uses, i, 18, 19, 22, 89 Kittatinny Ridge, Delaware Water Gap through, xiv, 169; rock weathering at, 776 Kiwis, xii, 243, 249 Klamath Mountains, iii, 214 Klebs, Edwin, x, 141, 155 Knee-cap, ix, 69, 70 (fig.) Knee Jerk, ix, 136 Knitted Goods, threads in, v, 277 Knitting machines, inventions, v, 282-3, 377, 378, 379 Knots, tying, by machine, v, 247-8 Knotweeds, xiii, 194 Knowledge, Bacon on, xi, 10; Bergson on intuitive, xvi, 196; Greek theories, 87-8; growing thirst for, vi, 330; relativity of, xvi, 195-6; St. Augustine on proper, 99-100; science and, 39-40, 41-2; scientific, remarks on, iv, 26; transmission means, xv, 142, 145-6, 167 Koch, Robert, x, 149-50, 169, 292, xvi, 184, 185; "postulates" of, x, 150, 160, 196 Kodak, invention, v, 382 Koenig, acoustician, iv, 52, 233 Kohl-rabi, xiii, 223, 333-4 Kopjes, of S. Africa, xiv, 82 Korea, geology of, xiv, 125 Kraft Paper, v, 294 Krakatoa Eruption, xiv, 324-5; atmospheric waves from, i, 188, xiv, 324; distances heard, i, 188; dust from, 57-8, iii, 100-1, xiii, 344, xiv, 325; noctilucent clouds from, i, 18; plant and animal extinction by, xiii, 345, xiv, 278 Krakatoa Island, xiv, 324; restocked after eruption, xiii, 344-5, xiv, 278 Krasnoiarsk Iron, ii, 284 Kril, xii, 19 Krypton, in atmosphere, i, 11, 12; symbol and atomic weight, viii, 383 Kut-el-Amara, i, 308 Labor-saving Machinery, remarks on, vii, 73-4, 75, xi, 268 Labrador, auks of, xii, 265; climate of, xiv, 345 Labrador Current, i, 345, xiv, 305 Labradorite, iii, 329 Laccoliths, xiv, 109 Lace Coralline, xii, 47 Lace Leaf Yam, xiii, 89-90, 32 (illus.) Laces, machine-made, v, 287-8 Lactic Acid, viii, 222, 223, 248, xi, 24-5; fatigue product, 271-2; stimulant, 272-3; from fermentation, x, 138; in body, 280 Lactometer, iv, 113 Ladakhis, character of, xiv, 245 Ladybirds, xii, 122; lemon tree scales and, xv, 22 Laënnec, René, T. H., x, 108-10 Lag, angle of, vii, 362; in electric currents, vi, 167; correction, 262 Lagrange, mathematical work, xvi, 105, 125; scientific work of, ii, 15, 71-2, 73, 74, 75, 216, 375 Laid Paper, v, 296 Lake, Simon, submarine of, v, 382 Lake Dwellers, agriculture, xiii, 210; houses and implements, v, 14 Lakes, iii, 142-57, xiv, 198-212; color of, viii, 40; economic importance, xiv, 212; ephemeral character, iii, 142, xiv, 198-9, 209-12; few in mature regions, xiv, 160; freezing of, iv, 150; processes of destruction, iii, 157, xiv, 198, 210-12; salt, 206-9; shore-line development, iii, 57-8; sizes and depths, xiv, 204 Lake Superior Region, glacial topography of, xiv, 56; mines, iii, 356-7, 358, 361, viii, 163; rock formation, iii, 172, 175, 176-7 Lakeview Gusher, iii, 354 Lamarck, cloud classification, i, 97; on inheritance of acquired characters, ix, 325-6; paleontological work, xvi, 169 Laminated Construction, vi, 316, vii, 371 Laminated Magnets, vi, 34 Lammergeiers, xii, 261 Lampblack, viii, 47 Lampreys, xii, 130-1 Lamps, portable, vi, 276-7, vii, 68-9 Lamp-Shells, xii, 47-8 Lancashire Cotton Mills, xiii, 236 Lancelets, xii, 129 Lancisi, x, 98, 154 Land, Land Surfaces, always some unsubmerged, xiv, 19-20; area and distribution, 20-2; area measurements, 10-11; changes in features of, 28-30; character of old and new, iii, 33-5, xiv, 48-9, 155-63; elevation distribution, 26-7; forms determined by earth movements and erosion, xiv, 33-79; forms determined by rocks, 80-113; heating and cooling of, i, 208, xiv, 346; level changes (see Level Changes); oldest, iii, 168-9; relief features, orders of magnitude, xiv, 27; rock formation, 19; wind variations on, 351 (see also Continents) Land-and-Sea Breezes, i, 131, 376 Land Animals, beginnings of, iii, 20, ix, 176; development of, iii, 285-6, xii, 167; salt in body fluid of, ix, 175-6 Land Filling, by machine, v, 258-9 Landlocked Areas, of continents, xiv, 190 Land Plants, beginnings, iii, 252; development, xiii, 304-22 Land Plaster, iii, 376 Landscape Gardening, xiii, 267-97; color contrast and induction in, xi, 95 Landscape Painting, xv, 302 Landscapes, changes in, iii, 10, xiv, 28; dramatic interest in, xiii, 11 Land-sculpture, xiv, 30 Lane's Law, ii, 309, 371, 380, 383 Lanfranchi of Milan, x, 38, 39 Langenbeck, Bernard von, x, 130-1 Langley, Prof. S. P., aeronautical work, iv, 43-4, v, 231, 382; astronomical work, ii, 144, 169, 213, 223-4; measurement of heat of moonbeams, iv, 301; on the camera, ii, 221; spectrobolometer, 128, 186 Language, xv, 141-2; association principle in, ix, 151-2; clearness of, xi, 379; importance of, ix, 152-3, xv, 68, 142, 143, 145-6; inadequacy in feelings, 143; making of, xv, 140-63; psychological importance, xi, 200, 224, 225; race and, xv, 159; thought and, 143-5, 146 Languages, Aryan and Semitic, xv, 161-3; changes in, 154-6; difficulty of learning new, xi, 201; foreign, advantages of learning, xv, 146; foreign, sound of, xi, 103; relationships and common origin, xv, 159-63 Lantern Gears, v, 27-8 Lanterns, enlarging and projecting, iv, 341-2 Lanthanum, symbol and atomic weight, viii, 383 Lap, cotton, v, 272; wood pulp, 293 Lapilli, volcanic, xiv, 323-4 Laplace, asteroid hypothesis, ii, 258; mathematical work, xvi, 105, 125; nebular hypothesis, ii, 369-72, 374-5, 378, 380 (see Nebular Hypothesis); on sound velocity, iv, 198-9; other work, ii, 15, 72, 73, 74, 87 La Plata River, connections of tributaries, xiv, 187; fish of, xii, 160 Lapwings, xii, 262, 263 Lard, animal fat, viii, 246; calories in, ix, 299; vitamins absent in, x, 261, 262 Larks, xii, 268 Larmor, light theory, xvi, 137-8; magnetism theory, 193 Larrey, Jean, x, 130 Larvæ, affected by light, x, 253; used in nest repairing, v, 10; "rains," i, 356-7 Larynx, aphonia of, x, 29-30; infection center, 220 La Salle, xiv, 192 La Soufriere, eruption of, xiv, 28, 338 Lassen Peak, iii, 103, 226, 176 (Pl. 10); activity of, xiv, 315 Latent Heat, iv, 152-3, v, 169, 353-4, viii, 37-8, 378; of fusion, iv, 152, 160, 161, 162; of vaporization, 173-4, 187 Latent Period, of pain, xi, 121; of sound, 105; of touch, 111 Lateral Line, of fishes, xii, 137 Lateral Moraines, lakes formed by, xiv, 202 Lathes, development of, v, 42-6, 47, 52-3, 376, 378, 380, 383 Latin, in animal classification, xii, 29; in cloud classification, i, 98; in plant classification, xiii, 169; languages derived from, xv, 160, 162 Latitude, barometric corrections for, iv, 122-3; color of skin and, xv, 36-7; of ships, how determined, v, 65; plant distribution determined by, xiv, 364-6; temperature and, 344-5; weight of bodies, affected by, iv, 101-2 Laudanum, discovery of uses, xvi, 109; first prepared by Paracelsus, x, 50 Laughing Gas, viii, 71, x, 123-4; critical temperature and pressure, iv, 172 Laughter, emotional control of, ix, 164; in infants, 349; kinetic theory, xi, 355-7; psychology of, 350-7 Laurel Family, xiii, 196-7 Laurel-leaf Points, xv, 109 Laurel Magnolia, xiii, 318 (fig.) Laurent, chemist, xvi, 162, 163 Laurentian Highlands, antiquity of, xiv, 235 Laurentide Glacier, iii, 238 Lava, iii, 380, xiv, 17-18; fissure flows, iii, 105-6; forms of fragments, xiv, 323-4; heat of molten, iii, 106-7; heat retention by, xv, 230; in Hawaiian craters, iii, 103, 104, 105, xiv, 322-3; porous, iii, 101 (see Pumice); rate of flow, 104-5; sheets, 102 (fig.); soils from, 28, xiv, 329; spine of Mount Pelee, iii, 103 Lava-dam Lakes, iii, 156 Lava Formations, xiv, 102-4, 164, 170, 172, 188; erosion effects, 103-5; extent of, iii, 106; in Appalachian trough, 212; in British Isles, 191; in Colorado, 177; in Columbian Plateau, 105-6, 227, 228, xiv, 102-3, 104, 164, 170, 172, 188; in Deccan of India, 105-6, 228, xiv, 103; in East Africa, 103; in Keewatin Series, iii, 169; in Lake Superior region, 177; in Snake River Valley, 228 Lava Rocks, not crystallized, iii, 170-1 Lavender, source, xiii, 205 Laveran, Alphonse, x, 155 Lavoisier, chemical work, xvi, 120, 121, 159-60, 177; combustion theory, viii, 34 Law, beginning of, xv, 360-3, 367-74, 379-80 Lawn Sprinklers, revolving, v, 143 Laxatives, use of, ix, 252 Lazear, Dr. Jesse W., x, 160, 162 Lead, affinity intensity, viii, 128; alloys with tin, melting point, iv, 161-2; atomic weight, viii, 189, 383; commercial source, iii, 330; compounds, viii, 29, 162; density of, iv, 113; extraction from ores, viii, 270, 271; from radium disintegration, 185; fusibility, 384; melting point and requirements, iv, 162; occurrence of, viii, 129; opaque to X-rays, vii, 250, 251; ores of, viii, 154, 198, 199-200; positiveness, vi, 59; production, iii, 362-3; properties, viii, 126-7, 154, 162; refining of, 272; refining, electrolytic, vii, 320; specific gravity, viii, 384; symbol, 383; test for, 287, 288; uses, iii, 362, viii, 162 Lead (of electric currents), vi, 171-4, 261, 262; angle of, vii, 362 Lead Arsenate, viii, 169 Lead Cells, vi, 130, 146-7, 150-1, viii, 167-9 Leaders, of crowds, xi, 332-3; of primitive peoples, xv, 363-6 Lead Pencils, graphite of, viii, 43 Lead Peroxide, in storage batteries, viii, 167-9 Lead Pipes, corrosion of, viii, 162 Leadville Mining District, iii, 363, 364 Leaf Mosaic, xiii, 38 Leafstalks, xiii, 34, 35 (fig.); light effect on, 87-8 Leakage, electrical, vii, 10-11, 371 Leaning Tower of Pisa, ii, 53, iv, 100-1; Galileo's use of, iv, 28, 97 Learning, Egyptian advice, xvi, 70; experience and, viii, 269 Learning Processes, xi, 33-46, 68; rules, 211-15 Leather, making of, viii, 257 Leather Collar, Maudsley's, v, 99 Leaves, xiii, 32-43; absent in some plants, 15, 28, 30, 31, 99, 100; arrangement on stems, 38; branches as, 378, 379; buds of, 34; colors, 42; coloring in autumn, 79; coloring in tropics, 361; compound, 36-7; first, 60-1; forms and varieties, 34-6; fossils of, 302; functions, 37-8, 42, 61, 77-84; hairy covering, 104-5, 379; insect-capturing, 39-41; light and, 38-9, 87-90; large, examples, 189, 217, 359; moving, 105-6, 113, 114; none in fungous plants, 70; not decisive in family grouping, 184; of desert plants, 41-2, 106-7, 378, 379-80, xiv, 378-9; of evergreens and deciduous trees, xiii, 174, 175; of ferns, 63, 65; of monocotyledons and dicotyledons, 176, 178; osmotic pressure, 94; reproduction by division of, 165-6; rigidity of, viii, 338; shedding of, in dry periods, xiv, 369; skeleton (Madagascar yam), xiii, 90; sleeping, 88-9, 113; stems acting as, 28-31, 378; structure, 78-9; struggle for sunlight, 38-9, 87-90; tendrils on, 38; transitional form, 43; transpiration, 103, 104, 113, 374, 378, 379; uses, summarized, 42-3; veins, 32-3; water-dripping, 107-8; water-storing, 41-2, 106-7, 379-80; water-supply methods, 102-9; wilting, 102, 103, 114 Leblanc Process, viii, 276-7 Leclanche Cell, vi, 138 Lee, Dr. Willis T., i, 47 Lee, William, knitting machine of, v, 283 Leeches, xii, 51, 55-6 Leeuwenhoek, Antonius von, xvi, 107-8, 112 Legs, bones of, ix, 68-9, 70 (fig.); bones, growth, 56, 58; equal length, 169-70; evolution of, xii, 167; in insects, 102; length of men and apes, xv, 57, 59; muscles of, ix, 76; nerves of, 124-5; vestiges of, in snakes, xii, 213 Legumes, xiii, 56; nitrogen fixation by, viii, 74, 346, xiv, 66 Lehigh River, gap of, xiv, 51, 167 Leibnitz, mathematical work of, ii, 14, xvi, 105; monad theory, 117-18; scientific work, 113 Leif Ericson, xiv, 261 Lelande Cell, vi, 137, 139 Lemmings, xii, 290, 291 Lemon Oil, viii, 240, 252 Lemon Tree, origin, xiii, 225; scale on, xv, 22; spread, xiii, 354 "Lemuria", xii, 192 Lemurs, xii, 374-6; primates, 373; feet of, iii, 301 (fig.) Length, British units, iv, 45, 69, 283; measurements and standards, xvi, 130; metric units, iv, 46, 69, viii, 28 Lenoir Motor Car, v, 213 Lenses, iv, 337-8; achromatic, iv, 372-3, xvi, 125-6; Bacon's improvements, 101; for eye defects, ix, 111, 112, 113, 114; formation of images by, iv, 337-42, ix, 108-9; of eye, 109-11, 113 (fig.); refraction of light by, ii, 99 Lenticels, xiii, 26 Lenticular Clouds, i, 104, 376 Lentils, xiii, 198, 223 Lenz's Law, vi, 311, vii, 371 Leonardo da Vinci, anatomical work of, x, 51-2; astronomical work, ii, 41; idea of moving bodies, 63; views of fossils, iii, 14 Leonids, ii, 288 Leopards, xii, 357; deer-hunting with, xv, 223 Lepidoptera, xii, 115-20; "blood rains" of, i, 358 Lepidosirens, xii, 142, 166 Leprosy, immunity and susceptibility to, xv, 50, 51 Lesions, meaning, x, 98, 322; X-ray treatment, vii, 253, 255-6 Lettuce, as food, ix, 27, 30; family, xiii, 206; origin, 223; wild, 105 Leucippus, theory of matter, xvi, 83, 84, 118 Leukaemia, metabolism in, x, 272 Leucocytes, germ destruction by, x, 209-10 Levees, effects of, xiv, 162 Level Changes, iii, 76-83, xiv, 33-6; due to earthquakes, iii, 97, 98; due to lateral pressure, 85; effect on erosion cycles, 36-7, xiv, 40, 163-4; shown by erosion of rocks, iii, 171-2 (see also Elevation, Rejuvenation, Subsidence) LeVerrier, astronomical work of, ii, 16, 79, 189, 269; meteorological work, i, 217, 228 Levers, v, 21-5; Archimedes on power of, iv, 25; classes of, remarks on, 89; clubs as, v, 12; friction in, iv, 93; legs as, v, 215; liquid, 97-103; mechanical gain in, iv, 41; primitive beginnings of, 24, v, 9, 14-15; principles shown by Archimedes, xvi, 89; revolving, v, 25-35 "Leviathan," steamship, v, 193-4 Leviathan Reflector, ii, 16-17, 105-6 Levulose, viii, 226, 248 Lewis & Clarke reports, xvi, 171 Lewis Machine Gun, v, 365-6 Lex Talionis, xv, 371 Leyden Jar, iv, 267, 368 (fig.), vii, 259, 260; discovery and experiments, xvi, 188-9; oscillations of, iv, 313 Lianes, xiii, 362, 363, 366 Liberty Engines, v, 53-4 Libyan Cat, xii, 355 Libyan Desert, rain in, i, 210 Lichens, species, xiii, 323 Lick Observatory, ii, 142-4, 148 Licorice Plant, leaves, xiii, 113 Liebig, Justus von, x, 126; chemical work, xvi, 162; on fermentation, x, 138-9 Liège, siege of, xiv, 92 Life, antiquity on earth, xiii, 314; beginnings on earth, iii, 20, 173, 249, xv, 71; Bergson on, xvi, 196; brain in relation to, xi, 15; Brunonian (excitability) theory of, x, 89; cell basis of, ix, 17, x, 119, xii, 10, 14, xv, 16, 381; chemical nature of processes, viii, 353, 355; chemical theories of, x, 69, 84; colloidal theory, xii, 11-13; conditions necessary, ii, 242-5; conscious, parts concerned in, ix, 21-2; demand for, in nature, xiii, 69; dependence of, on sugar products, ix, 27; distinctions from inorganic realm, xii, 13-14; fundamental instincts, xi, 49-56; Hoffman's "ether" theory, x, 85; instinct for renewal, xiii, 116, 167; instinct of preservation of, x, 9-10, 282-3; interest and triteness, vi, 330; irritability theory of, x, 86, 87, 89; James on complexity of, 244; low temperature effects, i, 32; maintenance of, ix, 18-23; mechanical explanations of, x, 70, 71, 72; metals congenial to, viii, 148; nature of processes, ix, 34; necessity of water, xi, 66; only thing man cannot produce, vii, 310; origin, ii, 243, 245, xii, 9-13, xiii, 300-1; Paracelsus on process of, x, 49; possibility in other worlds, ii, 242-53; possibility on Mars, 228-32, 237-8; protoplasm the seat of, viii, 356, ix, 13, 17, x, 228, xiii, 74; recent lengthening in U. S., x, 291; salts in relation to, ix, 174-5; savage attitude toward, xv, 327; seat of, in body, ix, 11-12, 17; sea water favorable to, viii, 355; signs (proofs) of, ix, 9-17; soul as source of (Stahl), x, 84; spontaneous generation of, 139; temperature in relation to, ii, 249, v, 348, x, 250-1; universality, Indian belief, xvi, 44 (see also Vital Processes) Life Plant, xiii, 165 Lift, of aeroplanes, i, 288, 298 Lifting Magnets, iv, 289, vi, 86, 94 Lifting Pump, iv, 126 Lift Locks, of canals, v, 103 Ligaments, ix, 70-1 Ligatures, history of use of, x, 14, 27, 55-6, 91, 121-2, 123, 129-30, 146, 148 Light, iv, 322-34; aberration of (see Aberration of Light); absorption in space, ii, 160, 354-5; absorption of, by objects, iv, 364; actinic effects, vii, 250; artificial, applications of, iv, 50-1; artificial, colors, of, ix, 115; bacteria destroyed by, viii, 332; body regulation to, x, 250; chemical action of, viii, 171-2; chromatic aberration, ii, 99-100; corpuscular theory of, iv, 47, 50, xvi, 136; decomposition, ii, 99, 111, 112, iv, 357-9 (see also Spectrum, Spectroscope); deflection of, 330, 374; deflection by sun, ii, 81-2; diffraction, i, 183, iv, 326; effects of objects on, 323-4; effects on organisms and man, x, 253-4; Einstein theory, ii, 80-2; electrical production, inefficiency, vi, 268; electromagnetic theory of, iv, 54, vi, 25, vii, 371, xvi, 137-8; eye and, vi, 270-2, xi, 86, 95-6; eye regulation to, x, 254; from sun, importance of, ix, 25-6; "gentleman" of physics, iv, 50; glowing effects on minerals, vii, 254; injury from excessive, 153; intensity unit, iv, 351-2; interference of, 376-8; instinct of seeking, xi, 52-3; invisibility, iv, 333-4; machines responding to, v, 331-2, 332-3; measurement of illumination of, iv, 350-2; measurement of intensity, viii, 374; monochromatic, iv, 364, 365; of electric lamps, vi, 268; of firefly, 268; of glowworms, xvi, 144; of moon, ii, 200; of stars, 296; of sun, 168-9; penetration of ocean by, xii, 22; perception limits, iv, 360-1; perception of, in animals, ix, 105; physiological sensation, vii, 249; polarization, iii, 319-20, iv, 353-6; polarization, discovery, xvi, 119; production by various kinds of rays, iv, 378-80; quantity unit, 352; radiant energy, 322, ix, 114; rays of, iv, 323; reflection and refraction (see Reflection and Refraction); seeing by, iv, 322-3, 324-9; shadows cast by, 332-3; theory of, present state, 50; transformed to musical sounds, v, 332-5; transmitted by ether, vi, 119, 120, 269, vii, 259; traveling of, in straight lines, iv, 330; velocity, 323; velocity constancy, xvi, 196; velocity in different media, iv, 327; velocity, methods of obtaining, ii, 59-60, 91, 167; vibrations and colors of, ix, 115; wave theory, iv, 47, 353, vi, 118-19, 269, xvi, 136-8; wave theory discovery, 119; white (see White Light); wind effects on, iv, 211 (see also Light Waves, Sunlight) Light-headedness, production of, ix, 266-7 Lighthouses, strength of, xiv, 300-1 Lighting, art of, modern advances in, iv, 50-1; direct, xi, 277, 373; emotional effects, vi, 273; factory, xi, 361; flood, vi, 283; modern gas, viii, 60; proper and improper, vi, 273-5; unit of intensity, vii, 368 (see also Electric Lighting, Lighting Systems) Lighting Systems, color effects, iv, 370; exterior, vi, 278-83, vii, 339-43; interior, vi, 275-8, vii, 68-72 Lightning, i, 146-57, vii, 201-19; annual deaths by, x, 254; awe-inspiring power, vii, 201, 202; causes, i, 149-52, iv, 269, vii, 206-15, 217-8; current strength, i, 152-3; danger and protection, 155-7, vii, 201-2, 218-19; danger in aeronautics, i, 303; defined, 376, vii, 371; displays, 203; distance, how determined, i, 187, vii, 210; electromagnetic waves from, 260; fire from, xv, 320; Franklin's experiment, i, 141, vi, 10-11, 14-16, vii, 204-5; large raindrops and, 215-17; multiple flashes, i, 146-8; nitrogen fixation by, 13, 34-5; oscillations, vii, 208, 366, 374; ozone produced, i, 15; photographic study, 146-8, 151; protection of electric lines, vii, 16-19, 49-50; thunder from, i, 192-3, vii, 210-11; types, i, 146, 148-9, vii, 205-6, 211-15; visibility, i, 152; voltage, 151-2, vii, 206-7; weathering agency, iii, 24; wind effects, i, 148 Lightning Arresters, vii, 17-18, 49-50, 362, 371 Lightning Prints, i, 154-5, 376 Lightning Rods, i, 156-7, 376, iv, 270, vii, 218-219, 371; invention, i, 141, vi, 14, 16; principle, vii, 209; use of points, vi, 297 Light-Pillars, i, 376 Light Waves, iv, 353, vi, 118-19, 269; atmospheric effects, i, 165-6, 170-1; caused by molecular vibrations, iv, 360, 363, 379; Doppler's principle, ii, 119, iv, 210; glass and, 183; interference of, 376-8; length and frequency, vii, 250, 260; length and frequency with different colors, iv, 359, 360, 365, ix, 114, 115; motion of, xvi, 137; unit of length, iv, 359, xvi, 130 Light-Year, ii, 315, xvi, 33 Lignite, iii, 344, 345, 346, 347, 348, viii, 44, 45 Lilac, fertilization, xiii, 143-4; leaves, 38 Lilienthal, Otto, v, 231 Lily, African, xiii, 38; leaves, 38, 176 Lily Family, xiii, 183-4 Lily of the Valley, xiii, 45, 47, 178 Lima Beans, variation in, xiii, 331 Limacina, xii, 19 Lime, calcium oxide, viii, 149; in earth's crust, iii, 308; in water, viii, 40, xiv, 142, 147; production, iii, 373, viii, 150, 276; slaking of, 38-9; uses, iii, 373, viii, 149-50, 278, 323, 347 Limes (fruit), origin, xiii, 225; spread, 354 Lime Salts, body needs of, ix, 32, 33, 33-4, 174; in bone, 57; in diet, x, 256 Limestone, iii, 13, 380; cliffs of, jointing in, xiv, 133; composed of carbonate of lime, iii, 25, 308; destruction by frost, xiv, 76-7; formation of, viii, 152; lime making from, 149, 150, 276; marble from, iii, 169, 189, 371; occurrence in U. S., 371-2; polyzoans in, xii, 47; residual soils from, xiv, 68, 145; sedimentary rock, 18; solubility, iii, 24-5, 126, viii, 151, xiv, 145-6, 147; travertine deposits, 146; uses, iii, 325-6, 373-4, v, 315, 318, viii, 151, 280; weathering of, iii, 27 Limestone Formations, iii, 185, 267, 270; caves in, 127, viii, 151, xiv, 147-8; underground streams in, iii, 116, xiv, 149-50 Limonite, iii, 333, 359, viii, 130, 156 Lincoln, assassination incident, xi, 323; in Holmes's "goodly company," x, 134 Linden Trees, xiii, 324-5, 345-6 Linen, antiquity of, xv, 243; as clothing material, ix, 311-12, x, 307, 309; cellulose composition, viii, 254; from flax plant, xiii, 235; paper from, v, 290-1, 292 Lines of Force (electric), iv, 261-2, vi, 295-6 Lines of Force (magnetic), iv, 251-2, 261, 274-5, vi, 33, 54, vii, 371; cutting of, iv, 301-8, vi, 23, 54, 307-8; direction, iv, 277-8, vi, 54-5, 88-90; leakage, vii, 371; least resistance tendency, vi, 43-4, 96; shortest direction tendency, 219; terrestrial, 39, 40; terrestrial, in relation to aurora, i, 159-60 Line Squalls, i, 138-9, 376 Link Motion, v, 208-10, 379 Linnæus (Carl von Linné), x, 84, 134; natural history work, xvi, 116, 126, 139, 165; rattlesnake named by, xii, 235 Linotype, Mergenthaler, v, 308-10, 381-2 Linsangs, xii, 353 Linseed Oil, viii, 231-2, 246; action in paint, 264, 265; source, xiii, 235; spontaneous combustion of, viii, 55-6 Lions, xii, 359-60; fearlessness, xi, 136; instinctive fear of fire, 46; strength of, xv, 16, 18 Lipari Islands, volcanoes of, xiv, 317 Lipases, viii, 357, x, 326 Lipins, viii, 350-1 Liquefaction of Gases, i, 29, 32, iv, 143, 153, 171, 188, 191-2, viii, 303-4 Liquid Air, i, 26, 29-33, iv, 190-2, vii, 323, viii, 68; boiling point, iv, 173; oxygen production from, viii, 67, 274; temperature, and pressure, iv, 172 Liquids, boiling of, iv, 167-74; boiling point and chemical composition, viii, 298-301; boiling point and pressure, iv, 168, 169-72, v, 354, viii, 303-5; buoyant powers of, iv, 30, 103-7; chemical aspects, viii, 22, 297-301; compressibility, v, 107; conversion to gases, iv, 152-3, 153, 167; critical temperature, 171-2, viii, 303-4; density, how measured, iv, 113, vi, 147; distinguished by pressure and diffusibility, iv, 22-3; elasticity of, 156, 158; evaporation, 167, 174; expansion by heat, 135, 138; expansion coefficient, 145; fractional distillation of, 168; heat effects on, 144, viii, 25; heat transmission in, iv, 138-9, 177-8; intermingling of, in contact, 131; latent heat (see Latent Heat); molecules in, iii, 309, iv, 22, 131, 152, 167, 363, viii, 23, 24; osmosis, xiii, 90-1; pressure of, iv, 116-19; solubility in water, viii, 111-12; sound velocity in, iv, 198; specific gravity, how determined, 112, 113; spectra of incandescent, ii, 112, iv, 360, 363; supercooled and heated, viii, 113, 304-5; vapor pressure of, 303-5; vaporization of, iv, 173-4; vibrations of, 196, 215; volatile, 174 Lister, Joseph, x, 144-6, xvi, 182-3; importance of work of, x, 40, 107, 149, 381; on Pasteur, 143 Liter, standard of volume, viii, 28 Lithium, viii, 128, 132, 133; atomic weight and symbol, 383; flame color, 301; specific gravity, 384; spectrum of, 301-2; test for, 287, 289 Litmus, viii, 114 Little Falls Gorge, iii, 243 Little Red Riding-hood, xv, 358 Littoral Fauna, xii, 16, 17 Live Oaks, xiv, 370 Liver, bile secreted by, ix, 237, 275; changes caused by shock, xi, 59; development in black and white races, xv, 49-50; disorders of, x, 330; emotion effects on, xi, 136-7, 138; failure in diabetes, ix, 293; functions, x, 329-30, 347, xi, 60; gall stones in, ix, 286; glycogen storage in, 291, 292, 293, 298; hemoglobin decomposed in, 184, 275; in circulatory system, 196 (fig.), 198, 245; inflammation of, x, 224; secretin effects on, 325; therapy of, 382-3; urea production in, ix, 284, 285; waste removal by, 271, 275 Liverwort, reproduction, xiii, 166, 167 Livingstone, David, African exploration, xiv, 196; quoted, 78 Lizards, xii, 182, 203-10; descent of, 203; embryo of, xv, 54; Mesozoic, iii, 295 Llamas, xii, 313, 315 (fig.) Lloyd's, insurance of, i, 270 Load Factor, vi, 380-2 Loadstones, vi, 28-9, vii, 372; at magnetic pole, vi, 30; Gilbert's studies, 11, 12; used as suspended compass, 29, 31 (fig.); (see also Lodestone) Lobsters, iii, 260, 278-9, xii, 87 Locaille, xvi, astronomer, 124 Locke, John, medical work of, x, 74-5; philosophy of, xvi, 111, 115, 117 Lockjaw, x, 298-9; immunity to, 206, 207; prevention of, 218 Lockyer, Sir Norman, discovery of sun prominences, ii, 181; collision theory, 327, 333; star classification, 309-10; on temple orientation, 26 Locomotion, forms of, ix, 82, 155-6; friction necessary to, iv, 94; of animals, means of, ix, 73-4; of serpents, xii, 212; reflex processes in, ix, 156-9; rolling, v, 215 Locomotives, Steam, v, 207-12, 377, 378-9; boilers, 140 (see Boilers); efficiency, 155; compared with electric, vii, 193-4; power source of, ix, 15; smoke from, i, 64, vii, 345; sound of passing, iv, 210 Locomotor Ataxia, ix, 90-1 Locusts, xii, 108-9; jaws of, 100; seventeen-year, 112, 113; as food, xv, 134 Locust Trees, in landscaping, xiii, 271-2; in Long Island, 354; in pea family, 198; lightning danger, i, 155; petals, 47; sleeping of leaves, 89, 113 Lodestone, iv, 52-3, 242, viii, 156; name of, iv, 243, (see also Loadstone) Lodge, Sir Oliver, Evesham experiments, vii, 352; on atmospheric electricity, 212; on electrons, vi, 114; on forces in atoms, 115; on luminiferous æther, 118; wireless system, xvi, 191 Lodgepole Pines, xiv, 374 Loess, i, 53-4, iii, 73-4, 380, xiv, 63, 72-5 Loire River, base-leveled stream, xiv, 49 London, "Black Day," ii, 211; eclipses in, 214; fogs, i, 94; harbor of, xiv, 270; sewage disposal, viii, 327; smoke deposits, i, 65; tea market of world, xiii, 231; water purification, viii, 319-20 London-Paris Air Route, i, 44-5, 95, 285-6 Long, Crawford W., x, 124, 125 Long Branch, N. J., wave destruction at, xiv, 45, 302 Long Distance Electrical Transmission, alternating and direct currents in, vi, 159-61, 195-6; choke coils in, vii, 50; condensers in, vi, 285-6; difficulties, 367; high voltages best, 159, 161, 163, 331-2; high voltages and leakage, vii, 10-11; of Niagara Power Plant, vi, 376-8; power-factor correction, 262; present distances attained, 365; progress in, vii, 9-10; synchronous condensers in, vi, 262; three phase alternators in, 206; transformers, 309, 324; transcontinental, 10, 367-8; vacuum tubes in, 125 Long Distance Telephony, inductance reduction, vii, 104-5; method of connecting cities, 104; phantom circuit, 105-6, 119; repeating stations, 114; in United States, 91-2 Longfellow, stanzas on nature, xvi, 43 Long Heads, physical characteristics, xv, 47; racial divisions, xvi, 48-9; skull index in, xv, 42 Long Island, bowlders on, xiv, 69; locust tree on, xiii, 354; opossums in, xii, 275; outwash plain on, iii, 69; plant conditions, xiii, 382; scallop fisheries, xii, 65; terminal moraine on, iii, 68, 237, 238 Long Island Sound, false corals of, xii, 47; oysters of, 61; oyster "drills" of, 72 Longitudinal Rivers, xiv, 153-4 Looking-glass, images in, iv, 335-6 Looming, optical, i, 172, 174, 376 Looms, history and development, v, 268, 277-82, xv, 245-7; various inventions, v, 376-7, 381, 383 Loons, xii, 250 Loop-the-loop Cars, iv, 74 Loosestrife, xiii, 140-1, 203 Lop-Nor Desert, xiv, 209 Lorentz, light theory, xvi, 137-8; relativity theory, iv, 18, xvi, 196 Lories, Australian, xii, 266-7 Los Angeles, electric power supply, v, 81, vi, 363; telephone connection with New York, 367-8 Loudness, of sound, iv, 211; to what due, xi, 104 Louis XIV, high heels introduced by, x, 306; observatory founded by, ii, 58; on Pyrenees Mts., xiv, 239 Louis, Pierre C. A., x, 108 Louisiana cotton, xiii, 237; salt deposits, viii, 140; sulphur deposits, 76 Louisiana Purchase, xiv, 192, 193, 311 Louisville, early growth, xiv, 219; water supply, viii, 318 Loup Fork, xiv, 161 Love, fundamental impulse, xv, 185; motor character, xi, 58; sentiment of, 149-50; unknown to savages, xv, 279, 321 Lowbrows, xv, 43 Lowell, Percival, ii, 233-4, 237, 271; reference to, xi, 218 Lowell Observatory, ii, 146-7, 148 Low German, xv, 162 Lowlands, xiv, 213 Lows, Low Pressure Areas, i, 135-6, 137, 376; of Iceland, 361; movement, 134-5, 237; physiological effects, 330; thunderstorms and, 138; wind and weather attendants, 125, 218, 236, 237 (see also Pressure Areas) Lubricants, fatty, viii, 247; graphite, 43, vii, 308, 309; oil-dag, 300 Luciferin, xii, 20 Lues, curability of, x, 134; germ of, 195, 199; immunity to, 207 Lumber, chief source of, xiv, 383; from heartwood, xiii, 25 Lumen, light unit, iv, 352 Luminous Plants and Animals, i, 346-7, xii, 20, xiii, 203-4, xvi, 144, 146 Lunation, defined, ii, 196 Lundy, Lake, iii, 149 Lung Fish, iii, 283 (fig.), xii, 164-6 Lungs, ix, 254-6; aeration of blood by, 253, x, 62, 63, 331; carbon dioxide diffusion by, ix, 263-7; circulation of blood through, 196 (fig.), 198-200; congestion of, x, 341; development in black and white races, xv, 50; diseases of, susceptibility to, 50, 51; dust in, ix, 223; evolution in animal kingdom, xii, 164-5, 169, 187, 248; external respiration by, x, 339; functions in maintenance of life, ix, 21-3; infection through, x, 198, 220; in pneumonia, 289; oxygen supply through, ix, 51 (diagram), 253, 258; poisons exhaled by, 269; water loss by, i, 317, ix, 274 Lupine, leaves, xiii, 113 Luray Caverns, iii, 127, xiv, 148 "Lusitania," loss of, xi, 332 Luster, of metals, viii, 126; of minerals, 201 Lycopodium Selago, xiii, 305-6, 322 Lycopods, iii, 253-4, 256 Lye, making of, viii, 276, 278; in soap-making, 221 Lyell, geological work, xvi, 126, 171 Lymphatics, ix, 222-5; in circulatory system, 196 (fig.) Lynx, xii, 364-5 Lyra, elliptic nebulæ in, ii, 360; movement of sun toward, 18, 122, 137, 305-6 Lyric Poetry, primitive, xv, 319-21 Lysins, x, 211 Maas River, shifts in delta, xiv, 186 (see also Meuse) Macaques, xii, 378-9 Macaws, xii, 266 McCormick, Cyrus, reaper, v, 244-7, 249, 379 MacCulloch, on rocks, xvi, 170 McDowell, Ephraim, x, 122, 147 Mace, spice, xiii, 261, 262 Mace, symbol of power, xv, 208 McGehee, Arkansas, antimalarial work in, x, 174 Machine Guns, v, 362-8, 380, 382 Machines, advantages of electrical drive, vii, 62; air-cushioning in, v, 134; "animated," 326-44; contract with operators, vii, 121-2; displacement of men by, v, 17-18; early, iv, 26; efficiency (see Efficiency of Machines), elementary, iv, 89-94, v, 20-41; fascination of, vi, 175; force and resistance law, iv, 90, 92; for making machines, v, 42-56; friction in, iv, 92-4; history of development, v, 15-19, 376-84; hydraulic, reliability, 106; instruction of workers, xi, 363-5; labor-saving, vii, 73; mechanical advantage, iv, 89, 98; parts named from human parts, v, 20; skilled artisans and, 42, 46; standardization of parts, 48-50, 53-4; summary of progress in, 376-84 Machine Tools, development, v, 42-56, 376; in relation to automobile industry, 55-6, 214, 383 Mackerel Sky, i, 100, 376 Mackerel Year, i, 359 Mackintosh Waterproof Cloth, xiii, 245 Madagascar, chameleons of, xii, 210; crocodiles of, 199; former union with Africa, 376; fossane of, 353; lemurs of, 374, 375; laceleaf yam, xiii, 89-90; orchid, 48; ratite birds in, xii, 249; separation from Africa, xiv, 273; tenrecs of, xii, 367; tortoises of, 191, 192 Madder Family, xiii, 205-6 Madeira, discovery of, xiv, 309; oceanic volcano, 289, 316 Madrepores, xii, 39-40 Maeterlinck, on eelgrass, xiii, 150-1 Magazines, printing and binding, v, 305-7 Magdalenian Period, xv, 105, 109; clay models of, 118-19 Magdeburg Hemispheres, iv, 29 Magellanic Clouds, ii, 355 Magendie, François, x, 126, 127, xvi, 186 Maggiore Lake, iii, 146 Magi, Persian, xvi, 59 Magic, history of, xvi, 44, 59 Magic Lantern, iv, 341-2 Magma, viii, 191 Magnesium, viii, 17, 127, 148-9, 153; affinity intensity, 128; atomic weight and symbol, 383; automobile parts made of, 127, 149; electrolytic production, vii, 320-1; fusibility, viii, 384; ignition, 53, 54; in body, 354; in body fluids, ix, 174; in earth's crust, iii, 308, viii, 19, 129, 192, 195, 196; light of, 60, 172; plant needs of, 337, 341; specific gravity, 384; test for, 287, 289 Magnesium Chloride, in sea water, xiv, 295-6 Magnesium Compounds, viii, 130, 148-9; deposits of, 138, 195, 196, 275; in hard water, 40, 318, 322-4; lightness of, 29 Magnesium Oxide, medicinal uses, viii, 153 Magnetic Axis, of earth, iv, 250 Magnetic Blowout, vii, 37, 39 Magnetic Circuits, vii, 364; force of, vi, 93 Magnetic Disturbances, accompanying aurora, i, 161; due to moon, ii, 201; sun-spots and, 176, 186 Magnetic Equator, iv, 246 Magnetic Fields, iv, 251, vi, 31, vii, 368; concentration of, vi, 91-2; distortion, 43-4; electromotive force created by, 50-3, 54; electron theory, 128; generator and motor actions in, 218-19; of atoms, 117; of earth, iv, 253, vi, 39, 40; of electric currents, iv, 274-5, 277, 279 (fig.), vi, 19-20, 88-91; of sun, ii, 177-9; spectra of vapors in, 178; strength or intensity, iv, 252, vii, 368, 370 Magnetic Force, vii, 369 Magnetic Leakage, vii, 371 Magnetic Meridians, iv, 246 Magnetic Needle, iv, 243-4; dip or inclination of, 245-6; earth's action on, 248; electric current effects on, 273-4, 275-6, 278-9 Magnetic Permeability, vii, 372 Magnetic Poles, vii, 374; force of attraction between, iv, 249 Magnetic Poles (of earth), iv, 246, 248, vi, 29-30; aurora in relation to, i, 159-60 Magnetic Saturation, vii, 372 Magnetic Screens, vi, 32 (fig.) Magnetic Storms, vi, 40 Magnetism, iv, 242-55, vi, 27-45; daily application, xvi, 19, 30; effects on body, vii, 246, 247; electricity and, vi, 12, 19-20, 27-8, 86, iv, 256, 276; electron theory, vii, 371; energy in, iv, 82; force of, how measured, 249; history of, 52-5, vi, 9-26, xvi, 109, 122; law of attraction and repulsion, vi, 18, 42-3, 286-7; of direct and alternating currents, 155-6; lines of force (see Lines of Force); of earth, iv, 248-50, 252, vi, 29-30, 39-40; of earth, connection with internal iron, xiv, 11; of rotating bodies, ii, 178, vi, 21; residual, vi, 191, vii, 372; science of power, xvi, 36-7; term as used, vii, 372; universal presence, vi, 40 (see also Electromagnetism, Magnetic Fields, Magnets) Magnetite, iii, 333-4, viii, 156; ores in Adirondacks, iii, 359; properties of, iv, 242 Magnetization, iv, 242; aided by striking, 253; by electric currents, 286-8, vi, 30, 50; by induction, iv, 243, 253; by lightning, i, 152-3; by loadstone, vi, 29; internal effects, 36-7; of iron structures, iv, 253; molecular effects, 245, 253; processes of, vi, 44-5; test, 43 Magneto Generators, vi, 215-16 Magnetomotive Force, vi, 92-3 Magnetos, automobile, vii, 140-41 Magnets, iv, 242-4; action of, 250-1, vi, 31-2; aging of, 45, vii, 159; attraction and repulsion of, iv, 242, 244, 245, 249, vi, 33, 42-3, (fig.); demagnetization methods, iv, 253, vii, 366; effect on compass, vi, 27, 42-3; electromotive force produced by, iv, 303; force, how measured, 249-50; heat and jarring effects, vi, 34-8, 117; internal constitution, 36-7; laminated, 34, 35 (fig.); lines of force, 33 (see also Lines of Force); lifting force of, iv, 289; making of, vi, 44-5 (see Magnetization); natural, iv, 242; penetrability, 250, vi, 31-2; permanent and temporary, iv, 243, vi, 30; poles of, iv, 242, 244-5, 253, 262, vi, 31, 42, 43; types, 30-1, vii, 372; uses, commercial and industrial, iv, 255, viii, 270 (see also Electromagnets) Magnifying Glass, iv, 343 Magnitude, illusions of, xi, 184-90 Magnitude of Stars, absolute (see Absolute Magnitude); catalogued by Hipparchus, ii, 31; classification by, 295-6, 297; conditions affecting, 322; determined by photoelectric methods, 328; different kinds, 296; different stages, 383, 384; spectral type in relation to, 309 Magnolias, antiquity, xiii, 324-5; development, 55; fertilization, 130-1; former distribution, xiv, 375; fossil ancestor, xiii, 318; index plants, i, 255; in landscaping, xiii, 271-2 Mahogany, from tropical forests, xiv, 383; in anacardiaceae family, xiii, 200 Maidenhair Tree, xiii, 315-16; in landscaping, 271-3 Mail-Order Business, in stormy weather, i, 264 Maine, coast of, iii, 37-8, 57, 235, xiv, 256, 257, 262-3; coast destruction, 46; dikes on coast, iii, 110, xiv, 108; harbors, 268; moose of, xii, 318 Mains, electric, vii, 373 Maize, history and uses, xiii, 211-13 Major Triad (music), iv, 206-7 Make-and-Break (electricity), iv, 382 Malachite, iii, 334, 360 Malaise, sensation of, ix, 91 Malaria, x, 153-9; campaign against, 173-4, 299-301; control of, in tropics, xiv, 356, 357; former idea of causes, x, 286; quinine and, xiii, 250-1 Malaspina Glacier, iii, 70 Malay Archipelago, bananas native to, xiii, 216; continental relationships, xiv, 274; crocodiles of, xii, 201; lemurs of, 374, 375; largest flower in, xiii, 363-4; parrots of, xii, 266; rain forests, xiv, 369 Malay Peninsula, beriberi in, x, 257; coco palm of, xv, 125; leaf butterfly of, xii, 117; rhinoceros of, 306; snakes of, 214, 218; tapirs of, 306; tin production, iii, 369 Malays, hair of, xv, 37; immunity to tuberculosis, 51; in tropics, xiv, 356; members of brown race, xv, 37 Malic Acid, viii, 222-3, 336 Malicious Animal Magnetism, xi, 311 Malleable Iron, v, 319 Malleability, viii, 126; in mineral identification, 202 Mallow Family, xiii, 200 Malmags, xii, 374 Malpighi, Marcello, x, 77, xvi, 107, 112, 116, 126 Malt, viii, 249 Malta Fever, diagnosis of, x, 216 Maltase, viii, 357 Maltose, viii, 227, 241, 243, 244; in brewing, 249; formed in digestion, ix, 230 Mammals, xii, 270-384; Age of, iii, 20; appearance in Cretaceous, xv, 71; egg-laying, 272-3, 274; evolution of, xii, 185, 271-2; geological history, iii, 20, 297-306; growth in relation to flowering plants, 257; in oceanic islands, xiv, 277-8; order of succession, xii, 338-9; primitive types, 272-4; smallest of, 368; temperature maintenance in, ix, 307-8; warm-bloodedness of, 305, 306 Mammato-Cumulus Clouds, i, 104, 376 Mammoth Cave, iii, 127, xiv, 148; fishes of, xii, 163 Mammoth Coal Bed, iii, 201, 347-8 Mammoth Hot Springs, terrace, iii, 192 (Pl. 11); travertine deposits, 325, xiv, 146 Mammoths, xii, 301 (fig.), 302; of Ice Age, xv, 76, 79; prehistoric pictures of, 85, 86; remains found in Siberia, 16 Man, activities of, ix, 21; adaptation to environment by, xiv, 344, 363, xv, 25, 26, 28, 31, 36; adapted to mixed diet, ix, 246, 285; Age of, iii, 20; anthropology science of, xv, 10-11, 15, xvi, 36; antiquity of, ii, 19, iii, 301-2, 303, v, 11, xv, 11-12, 69-87, 95, 163; apes and, physically compared, xii, 373, xv, 57-62, 94; brain in, 39-41, 62-3, 96; broadened interests of, x, 10; cell development in, ix, 44; chromosome number in, 46, 339; dependence on fire, shelter and clothing, 308-9; descent of, 349, xii, 384, xv, 56; distribution over earth, xiv, 21, 344, xv, 12; distribution mostly on plains, xiv, 218-19; dominant impulses, xv, 185; educability, 66; embryological development, 53-5; environmental control of, xi, 33, 58, xiv, 30-1; environment conquest by, xv, 25-6; environment of present, x, 354; erect posture and walking, xv, 58; evolution of, iii, 283, 301-6, xv, 25, 26-31, 53-4, 70, 88-102; evolution, Anaximander on, xvi, 78-9; face and brain case in, xv, 43; fear in, origin of, xi, 136; fire generation confined to, ix, 308, xv, 229-30; fundamental instincts, xi, 50-6; grasp of, ix, 67-8; grouping tendency in, xv, 361-3; improvement by selection and education, xvi, 157; impulses conscious, xv, 273; increase in numbers, 26-7; infectious diseases peculiar to, x, 206; instincts and reason in, xv, 65-6, 68; language evolution, 140, 142-3, 146-63; language importance, ix, 152-3, xi, 224; "measure of all things," xvi, 85; origin of, various accounts and theories, xv, 69-70; Paracelsus on, x, 48; physical, xv, 32-52; physical measurements, comparative, 57; place in nature, iii, 260, 281, xvi, 126; primate, xii, 373; psychological unity, xvi, 42-3; races of (see Races); rate of growth in, ix, 32 (diagram); reasoning power, xi, 237, 243-4, xv, 65, 66, 68; relation to lower animals, 53-68; rudimentary structures in, 56; sense of smell, xi, 77-8; sex determiners in, ix, 338-9; skull capacity, xv, 40-1, 89; skull shapes in, 42-3; stages in development of, 188-204; structure compared with apes, 57-62; struggle for existence in, 25-6, 27; struggle for perfection in, 28-9; survival of fittest in, 27; symmetrical instinct in, 251; tool-using animal, v, 9, 10-11, ix, 67-8, xv, 205; tropical animal, ix, 308-9 (see also Primitive Man) Manatees, jaguars and, xii, 362 Mandan Indians, buffalo dance, xv, 305-6 Mandibles, of insects, xii, 99; of men and apes compared, xv, 94 Mandrills, xii, 379-80 Mangabeys, xii, 379 Manganese, viii, 154; affinity strength, 128; atomic weight and symbol, 383; electrochemical analysis, 295; fusibility, 384; ores, 198, 271; specific gravity, 384; test for, 287, 289 Manganin, resistance, vi, 77, vii, 364 Mangrove Keys, xii, 42 Mangle, Electric, vii, 82-3 Manhattan Elevated Railway, engines and turbines, v, 152-3 Manholes, construction, vii, 30 Mania, hot baths in treatment of, x, 311; of adolescence, 236-7 Maniacs, strength of, xi, 264 Manila Hemp, xiii, 236, 239-40 Manila Paper, source, xiii, 240 Manna, "rains" of, i, 355, 357 Mantids, xii, 107-8 Manual Labor, fatigue from, ix, 81; food requirements in calories, 297 Manufacturing Centers, of future, v, 173 Manufacturing Stage, xv, 187, 203 Manures, as fertilizers, viii, 342-3; as nitrogen source, xiv, 66; waste of, viii, 346 Map-Making, aeronautical, i, 45-8 Maple Tree, antiquity, xiii, 324-5; as forest tree, 86-7; fruit, winged, 57, 58 (fig.); in landscaping, 271-2; petals absent in, 195; seed dispersal, 343; source of sugar, viii, 242-3; in United States, xiii, 368, xiv, 372 (see also Sugar Maple) Maps, discrepancies in, xiv, 10-11; tinting of, iv, 130 Marble, iii, 371; green, 338; metamorphic rock, 380, xiv, 19; reaction with acids, viii, 37 March (of weather elements), i, 205, 376-7 Marchetti, Peter, x, 79 Marconi, distress signal system, vii, 284; wireless messages, 258, 259; wireless work, xvi, 191 Marconi Transmitting System, vii, 263-5 Mare Tenebrosum, i, 55 Mare's Tail Clouds, i, 99, 377 Margarines, vegetable, x, 261, 267 Marine Animals, conditions necessary, iii, 17; large, xii, 297-9, 333-5, 347; mollusks, 57-80; primitive types, 16-24, 26, 32, 128-9; worms, 45, 51, 54 Marine Climate, i, 208, 377 Marine Deposits, iii, 52-5 Marine Meteorology, i, 271-83; founding of, 216 Marine Rivers, xiv, 153 Marine Rocks, xiv, 19; found above sea level, iii, 82-3, 85, 132, 235; in mountains, xiv, 231 Mariner's Compass, iv, 253-4, vii, 365; invention and improvements, vi, 29, 41-2 Mariotte, Edme, xvi, 110, 111; law of, iv, 140 Markhor, xii, 325 Marmosets, xii, 376 Marmots, xii, 294-5 Marne, Battle of, defence of "Grande Couronne", xiv, 90; soldiers asleep on retreat, xi, 286-7 Marne River, topographical features, xiv, 89 Marquette, Père, xiv, 192 Marriage, xv, 273-95, 364 Mars, (planet), ii, 227-34; atmosphere, 228-32, 247; canals, 235-41, 248; distance, 235-6; Kepler's studies, 50; life on, 228-32, 237-8, 247-8; "lucid" planet, 264; motions and orbits, 50, 162, 163; photographic study, 131, 132; rotation period, 59, 377; satellites, 241, 110; size, 162, 163; surface study, 238-9; Tycho Brahe's studies, 49; weight, 76, 77-8 Marshes, draining of, by trees, xiv, 379; malaria and, x, 154, 300 Marsh Gas, iii, 345, 354, viii, 51; as ignis fatuus, i, 347, 348 (see also Methane) Marshmallow, family, xiii, 200 Marsupials, xii, 274-81; evolution of, 271 Martens, xii, 350, 351 Martensite, viii, 274 Martha's Vineyard, waves action, iii, 56 Martin, Prof. E. G., author PHYSIOLOGY Vol. ix Maryland, former volcanoes, xiv, 318; oyster industry, xii, 61 Maskelyne, astronomer, xvi, 124; mountain-weighing, ii, 68-9 Mass, defined, iv, 35, xvi, 130; density and, iv, 110; measured by beam balance, 102; momentum in relation to, 62-3; motion in relation to, 60-1, 63-5, 72, 78; standard units of, 46, 69, xvi, 130; weight and, iv, 35, 110, xvi, 130 Massage, ancient Chinese, x, 13; effect on lymphatics, ix, 223 Massasauga, xii, 235 Mastoiditis, ix, 61-2 Matches, friction and safety, viii, 88; invention of, xv, 232 Materialism, xi, 13-14; in mediæval philosophy, x, 35 Materia Medica, Mesue's work on, x, 32; 17th century improvements, xvi, 109 Mathematical Astronomy, ii, 15, 113-14; culmination of, 15, 71-2; spectroscopic methods in, 119-24 Mathematical Calculations, development of, xv, 181-4, xvi, 61 Mathematical Machines, v, 326-7 Mathematics, coordinates used in, iv, 16; Golden Age, ii, 15; history of development, xvi, 54, 60-3, 68, 71-2, 79-81, 88-90, 92, 94-5, 103-5, 113-14, 118-19, 125; practice of challenges in, iv, 89 Mather, Cotton, on disease, x, 380; on inoculation, 101 Mating Instinct, xiii, 116 Mato Tepee, xiv, 129-30 Matter, chemical energy of, viii, 267; chemistry, science of, 11, iv, 12; constitution of, 21, 23, vi, 35-6, 78, 108, 109-12, viii, 22-8 (see also Atomic Theory, Electron Theory, Molecular Theory); elasticity of, iv, 35-6; elements of, viii, 11-12, 16-21; energy and, iv, 12, 13-14; energies in, xvi, 15; energy loss, 134; ether in, iv, 181; fluxation idea, xvi, 194; fourth state of, iv, 54-5, xvi, 193; Greek theories, 77, 83-4, 86, 91, 118; indestructibility, vi, 128, viii, 110; inertia of, iv, 20; kinetic theory of, 30, 131; monad theory, xvi, 117-18; primary concept, iv, 15, 16; sciences of, xvi, 36-7; states of, iv, 21-3 (see also Physical States) Matterhorn, formation of, iii, 236 Matriarchy, xv, 295 Maudsley, Henry, inventions, v, 45-6, 99, 376 Mauna Loa, iii, 103-4, 107, xiv, 322-3; real height and diameter, 101, 225 Maury, Lieut. M. F., i, 216, 271-2, xiv, 288 Maxim Machine Gun, v, 363, 364, 382 Maxwell, Clerk, electromagnetic theory, iv, 54, 55, vi, 25, vii, 371; on loss of molecular energy, xvi, 134; on motor-dynamo discovery, iv, 54; on rings of Saturn, ii, 133, 265-6; prediction of electromagnetic radiations, xvi, 191 Mayans, number and time systems of, xv, 181, 182 (fig.) May Bugs, xii, 123 Mayflies, xii, 104 Mazama, xii, 325 Mazda Lamps, vi, 267, 268; ohms of, 75; sizes and light, vii, 153 Mazda Nitrogen Lamps, vi, 278 Meadow Pink, xiii, 133-5 Meals, agreeable surroundings, at, ix, 241, x, 319-20; alcohol at, ix, 244; bathing after, 313; eating between, 88; excitement at, xi, 374-5; soup value at, ix, 241, x, 320; water at, ix, 229 Meanders, iii, 380; in old and new areas, 33, 34, xiv, 162, 165; intrenched, 165 Measles, Brown's treatment of, x, 89; consumption and, 292; eardrum affected by, ix, 103; epidemic of 15th century, x, 59-60; first description of, 32; germ of, 200; Indian susceptibility to, xv, 48, 51 Measurements, British and metric systems, iv, 45-6, 69-70, viii, 27-8; chemical apparatus, 294, 295 (fig.); in different fields, vii, 151-2; sciences and standards of, xvi, 129-31 Meat, body heat production by, ix, 309, x, 271, 273; calories in, 269; calory loss in preparing, ix, 299; composition, viii, 362; cooking effects, 368; digestion of, x, 326; eating of, effects, ix, 384-6, x, 279; eating of, in relation to bile, ix, 275; food constituents in, 300; gristle of, 13; proteins in, 34, 35, 280; salted, tinned and dried, x, 263; salts and extracts of, viii, 366; structure of lean and coarse, ix, 75; vitamines in, x, 260, 261, 262, 266 Mechanical Advantage, iv, 89, 92, 93 Mechanical Equivalent of Heat, iv, 49-50, 140, 142, 189-90, v, 350-1, viii, 186-7, xvi, 131-3 Mechanical Progress, summary, v, 376-84 MECHANICS, Volume v Mechanics, "artisan" of physics, iv, 50; daily applications, xvi, 16-17, 19-20, 30; defined, iv, 25; history, xvi, 67-8, 72, 89, 91 Medical Education, requirements of, x, 367-8, 369; Rockefeller Foundation and, 172 Medical Humanists, x, 45 Medical Meteorology, i, 316-31 MEDICINE, Volume x Medicine, history of, x, 9-192, xvi, 59, 63, 70-1, 82-3, 95-6, 98, 106-9, 112, 126-7, 178-87; Paracelsus on science of, x, 49; science of, remarks on, 368, xvi, 15, 37 Medicine Men, xv, 349-53, 354, 359, 365-6 Medicines, electrical application of, vii, 247-8; quack, 240-1; plants used as, xiii, 249-55; specific, x, 49-50 Mediterranean Lands, climate of, xiv, 348-9, 358-9; source of cultivated plants, 381-2 Mediterranean Racial Group, xvi, 49 Mediterranean Sea, ancient civilization around, xiv, 290, 306-7, 358, 359; concordant coasts, 249; darkness at depths, 298; geology of, 290-1; petrels of, xii, 252; "pilgrim shell" of, 65; salt in, viii, 139, xiv, 296, 297; sponges of, xii, 32; temperature of waters, xiv, 299 Mediterranean Volcanic Belt, xiv, 316-17 Medium, technical meaning, iv, 382 Medulla, xi, 28, 29, 76 Medusae (jellyfish), xii, 36 Megabar, iv, 123 Megaphones, iv, 239-40 Megatheres, xii, 283 Melampus, xii, 68-9 Melancholia, of adolescence, x, 236-7 Melancholic Temperament, xi, 153, 205 Melanesia, xiv, 277 Melanesians, beards of, xv, 38; hair of, 38 Melting Point, iv, 153; chemical composition and, viii, 298-301; of various substances, iv, 161-2; pressure and, 153, 162, 163-6 Membranes, fluid equalization through, ix, 194, xiii, 90-1; vibrations of, iv, 101 Memory, xi, 208-17, ix; association of ideas in, 149-51; delayed nervous disturbances in, 141-2; of emotions, 154; hypnosis and, xi, 317-18; reason and, 243-4; right use, 378; seat of, in cerebrum, ix, 145, 146-7 Memory Colors, xi, 89, 220-1 Men, basal metabolism of, x, 271; brain in, xv, 39; color-blindness in, ix, 116, 340-1; hats of, x, 309; heart rate in, 334; height of, xv, 38; skull capacity, 40; susceptibility of, x, 240; voice vibration rates in, ix, 99 Mendel, Gregor, x, 231-2, 13, 333, xvi, 154; experiments on peas, ix, 328, 333-4 Mendel's Law, xiii, 333, xvi, 157 Mendeléeff, chemical work, xvi, 134, 163; classification of elements, viii, 177; prediction of elements, 180 Mendelian Theory, xvi, 156 Mental Activity, insomnia due to, ix, 219; seat of, 145-6; temperature effects, i, 323-4 Mental Fatigue, ix, 137-8, x, 247, xi, 269 Mental Healers, x, 242-3, 365 Mental Hygiene, xi, 368-82 Mental-Nerve Diseases, x, 353 Mental Processes, in brain, ix, 145, 147-54; similarity in all men, xvi, 42-3 Mental Tests, in diagnosis, x, 371; in vocational guidance, xi, 359-60 Mental Types, xi, 152-9 Mercaptan, smell of, xi, 80 Mercerized Cotton, viii, 255 Mercuric Chlorides, viii, 170, 333 Mercuric Mercury, test for, viii, 287, 288 Mercuric Oxide, instability, viii, 101; oxygen preparation from, 34, 170 Mercurous Mercury, test for, viii, 288 Mercury (metal), affinity intensity, viii, 128; atomic weight and symbol, 383; barometric column of, iv, 30; compounds, viii, 170; density of, iv, 113; electrical conductivity, 283; expansion by heat, 135; freezing point, 153; heat capacity, 155; light of, viii, 172; melting point and requirements, iv, 162, viii, 384; ores and production, iii, 370, viii, 198, 270; properties and uses, iii, 370, viii, 126-7, 170; specific gravity, 384; specific heat, iv, 155; use of, in syphilis, x, 60, 104; use of, in thermometers, iv, 135, 137, 153 Mercury (planet), ii, 189-90; atmosphere, 190, 246; life on, 245-6; "lucid" planet, 264; motion at perihelion, 79, 81; non-rotation theory, 377; orbit, 39, 73, 162, 163; size, 162; weight, 76, 77 Mercury Arc Converters, vii, 365 Mercury Arc Lamp, vi, 281-3 Mercury Arc Rectifiers, vi, 331, 333-9 Mercury Fulminate, viii, 145 Mercury Vapor, viii, 309 Mergansers, xii, 257 Mergenthaler Linotype, v, 308-10, 381-2 Meridian Photometer, ii, 297 Mesaba Range, iii, 358 Mesas, iii, 140, 380, xiv, 81, 82 Mesenchyme, xii, 26-7 Mesentery, ix, 59 Mesopotamia, ancient empire of, xiv, 306; astronomy of ancient, xvi, 70; British campaign, i, 308; cradle of human race and history, xvi, 46, 51; food plant center, xiii, 221, xiv, 381-2; mirage in World War, i, 173; ostriches of, xii, 249; photographic mapping, i, 47; present desert character, xiv, 219; scurvy in, during World War, x, 265; wild wheat of, xiii, 210 Mesozoic Era, iii, 20, 208-20; animal life in, 270, 272, 275, 285, 286; birds of, xii, 239, 242; divisions and species of, xv, 71; mammals of, iii, 297, xii, 271; marsupials in, 277; plants of, iii, 255, 256, 257; reptiles of, 286-95, xii, 183, 188, 194-5, 202-3; sharks of, 143 Messages, primitive methods of sending, xv, 165-7 Messina Earthquake, xiv, 340-1 Mesue of Damascus, x, 32 Metabolism, ix, 37, x, 268; calculation of, 269-70; daily total in calories, ix, 296, 297; disease in relation to, 302-4, x, 268-81; fatigue caused by, ix, 80, 81; food requirements for, 289, 295-301; protein, x, 277-80; protein effects on, ix, 301-2; rate of, how influenced, x, 270-1; studies of, 128, 382; temperature effects on, ix, 37, 306-7 (see also Cell Metabolism, Basic Metabolism, Functional Metabolism, Growth Metabolism) Metal-Bearing Deposits, iii, 355-70 Metallography, vi, 78, viii, 273-4, xvi, 175-6 Metallurgy, viii, 269-74; historical development, xvi, 51, 59, 74, 174-7 Metals, viii, 17, 126-74, 379; affinities (electromotive series), 127-9; affinity for sulphur, 76, 77; atomic weights, vii, 384, viii, 383; atomic weights in relation to activity, 133, 180; chemical analysis, 286-9, 291-2; colors of compounds due to, 312; common states of, iv, 153; compounds of, viii, 130, 146, 202; corrosion of, 13, 100; cutting of (see Cutting of Metals); electrical conductivity, iv, 259; electrification of, 257, 259; electrochemical analysis, viii, 295; electromotive positiveness, vi, 59; expanding on solidifying, iv, 150; extraction from ores, viii, 131, 269-72; groups of, 181-2; heat conductors, iv, 177, 178-9; identification of, viii, 201, 202, 313; industrial, 154; internal structure, vi, 78-9; in body, viii, 354; in sea, 197; melting point and requirements, iv, 162; melting points, viii, 384; occurrence, 129-31, 198-200; occurrence due to igneous action, xiv, 234, 237-8, 329; original form in earth, viii, 193; periodic classification, 180-1; plant uses of, 337, 341; positive ionization of, 122; potentials against hydrogen, vii, 383; rare earths, viii, 182; refining of, 272; refining, electrolytic, vii, 319-21; resistance (electrical), vi, 77-9; resistance tables, vii, 384; resistance reduced by low temperatures, i, 32; specific gravity table, viii, 384; thermoelectric powers, vii, 383; valency, vii, 384; welding by oxyacetylene blowpipe, 33; X-ray examination, vii, 257 Metamorphic Rocks, iii, 13, 380, xiv, 18-19; jointing of, 133; land forms in, 44, 113; ores in, 234, 237 Metamorphism, iii, 380; by molten intrusions, xiv, 112; fossils and, iii, 265 Metazoa, xii, 25, 26-7 Metchnikoff, x, 143, 201, 209-10, xi, 218 Meteoric Dust, i, 53, 56; in deep-sea deposits, xiv, 285 Meteoric Iron, ii, 292 Meteorites, ii, 290-3; energy from, ix, 25; iron and dust from, iii, 55; origin of life from, xii, 9 Meteorograph, i, 88, 377 Meteorological Instruments, i, 68-89; public display, 266-7 Meteorological Observations, history and organization, i, 212-23; marine, 272-3, 274-6 Meteorological Terms, i, 365-84 METEOROLOGY, Volume i Meteorology, daily interest, xvi, 13; defined, i, 7, 377, xvi, 37; history of development, 114, 177; organized, i, 212-23 Meteors, ii, 283-9; carborundum found in, vii, 310; cause of brontides, i, 196; dust from, i, 53, 56; former meaning, 7; in relation to corona, ii, 224, 225; in relation to solar system, 164; orbits, 287, 288, 289; photographic study, 134-5; planetesimal theory, iii, 162 (see also Meteorites) Meter, length unit, iv, 46, 69, viii, 27-8; radio unit, vii, 272; value in yards, iv, 70 Methane, viii, 51, 206; combustion products, 61; derivatives, 210, 230-1; flame of, 60; name of, 98 Methodism (medical), x, 26, 28, 29 Methyl, defined, viii, 379 Metric System, iv, 46; adoption in French Revolution, 136; advantage in specific measurements, 111; units in, iv, 69-70, 80-1, 154, viii, 27-8 Meuse River, xiv, 89; delta and shifts, 186 Mexico, ancient civilization (see Aztecs); century plants, xiii, 355; chocolate cultivation, 234; climatic belts, xiv, 223; copper production, iii, 360; corn-growing in ancient, xiii, 212; deserts of, xiv, 380; first hospital, x, 81; harbors and commerce, xiv, 265-6; jaguars of, xii, 362; lava fields, iii, 228; lead production, 362; new volcanoes in, xiv, 320; oil output, iii, 350, 354, v, 173; plateau and hot lands of, xiv, 221, 223; rivers of, 195; rubber plants, xiii, 248; serpents of, xii, 214, 234, 235; silver production, iii, 367-8; vanilla production, xiii, 260; yellow fever in, x, 163 Mexico, Gulf of, importance in rainfall distribution, xiv, 360; sponges in, xii, 32 Meyer, Lothar, xvi, 163; classification of elements, viii, 177 Mica, iii, 334; in granite, 308; chemical composition, viii, 90, 193 Mice, xii, 289-91; snakes and, 220, 227 Michelangelo, anatomical work of, x, 51-2 Michelson, interferometer, ii, 151, 322-3; standard length measurements, xvi, 130 Michigan, copper production, iii, 327, 360, 361; gypsum deposits, 376; iron ores, 357; salt deposits, 375 Michigan, Lake, size, xiv, 204 Micron, wave length unit, iv, 359 Microline, iii, 328 Micrometer, use of, ii, 58, vii, 151 Micronesia, xiv, 277 Microscopes, iv, 343-4; in chemical analysis, viii, 290-1; in medicine, x, 67, 128, 132, xvi, 112-13 Middle Ages, astronomy in, ii, 37-41, 42; comets of, 273; constructive work, 12; ermine fur in, xii, 350; European commerce in, xiv, 240, 241, 307, 308; falconry of, xv, 223; hail and lightning prevention, i, 341; hysteria epidemics in, x, 360; intellectual character of, 34, 35, 43; intellectual lethargy, ii, 11; Jewish polygamy of, xv, 289; magic, xvi, 79; medicine in, x, 31, 34-42, 43; meteoric showers of, ii, 287; minstrels of, xv, 323; painting in, 302-3; poisoning in, 228-9; science in, iv, 27-8; science and philosophy, xvi, 99-105; views of fossils in, iii, 14 Migrations, of birds, xii, 258, xiii, 55; of forests, xiv, 375-6; of plants, xiii, 348 Mikulicz-Rodecki, xvi, 183 Mil, wire measure, iv, 283, 382, vii, 373 Mil Foot, vi, 77 Military Meteorology, i, 306-15 Milk, amino acids in, x, 278; boiling of, viii, 368; calories in, ix, 299; composition, value and products, viii, 363; contamination and safeguarding of, ix, 347; digestion of, 235, 292; fat globules of, viii, 315; food constituents in, ix, 300; for infants, 33-4, 346-7; germs in, x, 193; milk sugar in, viii, 227; pasteurized, x, 139-40, 263, xiii, 71, ix, 347; snakes and, xii, 222-3; sour, and longevity, xiii, 172; souring of, 71; souring, lactic acid developed, viii, 223; typhoid fever from, x, 287, 288; vitamines in, 259, 260, 261, 262, 263, 266; vitamines and lime salts in, ix, 33-4, 347; water in, how measured, iv, 113 Milking Machines, vii, 227 Milk Sugar, viii, 226, 227, 363; digestion of, ix, 292 Milkweeds, flowers, xiii, 50; plumes, 343-4 Milky Way, ii, 350-6; discovery of separate stars, 96; Egyptian knowledge of, xvi, 69; Galileo's observations, 103 (see also Galaxy) Miller, Hugh, xvi, 169 Miller, Prof. W. J., author GEOLOGY, Vol. iii Milliken, Dr., vi, 121 Milling Machines, v, 47, 53, 378, 381 Millipedes, xii, 87, 88-9 Mills, Milling, development of, xv, 237-41 Mind, activities of, xi, 12, 25, 32, 236; body and, relations, 13-14, 61, 369-75; care and right use, 375-82; character of a good, 377-80; complexity, 206; conscious and subconscious, 47; differences and classes of, 152-9; difficulty of study of, x, 356; diseases of, 354-63; dominant traits, xi, 208-9; Emerson on common, 152; environment effects on, x, 237, 242-4; fatigue of, xi, 269; impairment by physical ills, 369-75; kinetic theory, 57-61, 123; meaning, 12, 13, 23-5, 32, 236; mechanism, meaning, 12-14; origins, 45; psychology as science of, 10-14; qualities revealed in smiles, 357; similarity in all men, xvi, 42-3 Mind of the Crowd, xi, 323-33 Mineral Matter, in animal and plant tissues, viii, 354-5; in ground water, xiv, 142-3, 144; in human body, viii, 348; in plants, 337, 339, 341, xiv, 65-6; in sea and surface waters, iii, 52, 127; in soils, viii, 338, 339, xiv, 68-9 Mineralogy, iii, 307-41, viii, 200-3; daily interest, xvi, 23, 29; defined, 38; history of development, 112, 126, 169, 173 Minerals, concentrations of, viii, 192, 195-200, xvi, 173; definition, iii, 307-8, 380, viii, 192, 200, 379; description of various, iii, 321-41; distinguished from living things, xii, 13-14; groups of, viii, 200-1; number of species, iii, 308, 315, viii, 200; properties and identification, iii, 309-21, viii, 201-3, 313; silicates, importance, viii, 193; veins, how formed, iii, 126 Mineral Salts, need of, in food, x, 256, ix, 33 Mineral Springs, xiv, 142-5; limestone deposits of, 146 (see also Hot Springs) Mines, Mining, coal dust explosions, i, 63; compressed air uses, 26, 27, iv, 129; deep shafts, iii, 120, v, 259-60; explosions caused by oxygen, i, 322, xiv, 12, 15; hot water in, 144; importance of faults, iii, 88, xiv, 37; mountains and, 237-8; oxygen in air, i, 322; science of, xvi, 36; temperature limitations, xiv, 15; underground water in, iii, 116; water-blasting in, v, 100 Mining Machinery, compressed air in, v, 128-9; sonic wave transmission, 108 Mining Schools, xvi, 126 Mink, xii, 349, 350 Minnesota, iron ores, iii, 357-8; lakes and lake basins, xiv, 200, 212; newness of topography, 158; moose of, xii, 318 Minnows, xii, 161, 163 Minstrels, mediæval, xv, 323 Mint Family, xiii, 204; petals in, 190 Miocene Epoch, iii, 221; species surviving from, xv, 71; tortoise of, xii, 191 Mira, classification, ii, 115; oldest known variable, 325 (see Omicron Ceti) Mirages, i, 172-4, 377, iv, 328-9 Mirrors, ancient, v, 109-10; fire generation by, xv, 232; images formed by, iv, 335-7; making of, viii, 171 Missing Link, xv, 56, 91 Mississippi-Missouri System, xiv, 153, 189 Mississippi River, aerial mapping, i, 47; course changed, iii, 98; delta, xiv, 53; depth and dredging at mouth, 270; discovery and exploration, 192; flood plain slope, 162; former steamboats, 193; harnessing of, v, 81-3; in American history, xiv, 192-3; meanders of lower, 162, 165; mineral matter in solution, iii, 127; overflow question, xiv, 71; paddle-fish of, xii, 151; salt content, viii, 139; sediment carried by, iii, 31, xiv, 53; upper, superimposed, 171 Mississippi Valley, alluvial soils of, xiv, 71; bowfins of, xii, 152; coal fields, iii, 348; development due to rivers, xiv, 31; earthquakes of 1811, 203; forests of, 378; French in, 192; geological history, iii, 35, 182-3, 187, 195, 206, 207, 231; growth of population, xiv, 193; loess deposits, i, 54, xiv, 72; panthers formerly in, xii, 363; precipitation in, xiv, 360; thermal springs absent, 143-4; thickness and composition of strata, 228-9; turtles of, xii, 187, 193; volcanic action in, xiv, 318; yellow fever epidemic, x, 160 Mississippian Period, iii, 20, 197-8, 380; animals of, 268-9; plants of, 252-3; sea extensions in, 193 Missouri, Ice Age in, iii, 239; loess deposits, xiv, 72; mining products, iii, 362, 364; sunk country, 98 Missouri River, course changed, iii, 245; in western emigration, xiv, 195; upper Mississippi, xiv, 153 Mist, i, 377, Brocken specters in, 184-5 Mistakes, analysis of, xi, 340, 379 (see also Errors) Mistletoe, xiii, 15, 100 Mistpoeffers, i, 195, 377 Mistral Winds, i, 133, 377 Mitchell, John, x, 116 Mitchell, Mount, xiv, 97, 168 Mites, xii, 98 Mixtures, compared with compounds, viii, 15; explosions of, 62; heat and cold production by, iv, 174-5; separation by vapor pressure, viii, 305 Mizar, double star, ii, 123, 334 Mocking Bird, xii, 269 Modesty, clothing and, xv, 253; custom and, 254-5 Mohammed Ibn Musa, xvi, 103 Mohammedan Astronomy, ii, 37-9 Mohammedanism, development of, xv, 199; polygamy allowed by, 289 Mohawk Valley, importance of pass, xiv, 194; origin, iii, 232; rock faulting, 91 Moissan, electrical work, xvi, 176; Arc Furnace, vii, 303 Moisture (atmospheric) climate determined by, xiv, 351-6; temperature effects, 352-4; vegetation determined by, 364, 366, 372, 377-8, 380, 381; atmospheric (see Humidity) Molar Solutions, viii, 118-19, 379 Molasses, production and use, viii, 242, 243, xiii, 215; vitamines in, x, 262 Mold, cause of formation, i, 61; disease-producing, x, 196; reproduction, xiii, 164 (see also Fungi) Molecular Theory, viii, 23-5; history of development, xvi, 91, 133-4 Molecular Weight, viii, 92; boiling point and, 299-300; diffusibility and, 108; differences, to what due, iv, 110; found by vapor pressure, viii, 305; in relation to actual weight, 109; of proteins, 351 Molecules, iv, 21, vi, 109, viii, 379; arrangement in relation to crystals, 203, xvi, 164; attraction of, viii, 306; possible variations in, iv, 143; condition at absolute zero, iv, 142-3; discrimination from atoms by Dumas, xvi, 162; dissipation of energy, 134; electrical balance and unbalance, i, 142, 143; electrical charges of, viii, 121; escape from liquids, iv, 167; ether in, iv, 181; formulæ of, viii, 91; fundamental vibrations of, iv, 363; in solids, liquids and gases, iii, 309, iv, 22, 131-3, 152-3, 363, viii, 23-4, 106; in solutions, 311-12; invariability law, 110; laws of, 106-10; magnetization of, iv, 245, 253; momentum, viii, 109-10; monatomic, 309; motions of, iv, 132-3, 363, viii, 23-5, 305-6; motion increased by heat, iv, 138-9, 144, 152-3, viii, 25, 37-8, 107, 108, 309, 310; number, vi, 112; number of, in gases, iv, 133, viii, 25, 108-9; polymerization, 219; size, vi, 112, viii, 24, 306; structure, 25-7, 306; structure, chain and ring, 233; structure, ether, 217, 224; structure in hydrocarbons, 51; structure in proteins, 351; structure and color, 258, 259, 312; structure and physical state, 207, 298; structure in relation to boiling and freezing points, 298-9; structure revealed by polariscope, 309; velocity of, iv, 133, viii, 24 Moles, xii, 366, 367-8 Molluscoids, iii, 259, 263, 270; origin of name, xii, 47 Mollusks, iii, 260, 272-6, xii, 57-80; deep sea, 23; in sea plankton, 19; sponges and, 32 Molybdenum, atomic weight and symbol, viii, 383; use and occurrence, xiv, 238 Moments of Force, iv, 382 Momentum, iv, 62-3, 66-7 Monadnock, Mount, iii, 232 Monadnocks, iii, 35 Monads, xvi, 117, 118 Mondeville, Henri de, x, 39, 40 Mongolian Orongo, xii, 327 Mongols, hair of, xv, 37, 38 (fig.); in yellow race, 37 Mongooses, xii, 351, 352 "Monitor," Ericsson's, v, 380 Monitors (lizards), xii, 208 Monkeys, xii, 376-9; embryological resemblances, xv, 54; expression of feelings by, 64-5; fear in, xi, 136; feet of, iii, 301 (fig.), xv, 61; first appearance, iii, 301; jaguars and, xii, 362; lemurs and, 374, primates, 373; resemblance to man, xv, 57; thumb in, 60 Monkshood, xiii, 196; aconite from, 252 Monochord, xvi, 82 Monocotyledons, defined, xiii, 60; evolution, 181; families, 181-9; first appearance, 319; leaves and flowers, 176, 179; stem formation, 177 (fig.); relative antiquity, 207; subdivisions, 179, 180 Monoecious Plants, xiii, 46 Monogamy, xv, 285, 289-94, 295; among birds, 276-7 Monorail Car, v, 342-3 Monosaccharides, viii, 223-6 Monotony, of work, xi, 275-6, 277-8, 280 Monotype, v, 310-12, 383 Monros, physicians, xvi, 179, 181, 186 Monsoons, i, 130-1, 377, xiv, 350-1; conditions resulting from, 359-60; use of, in early trade, 307 Montana, bad lands of, xiv, 82; fossils found, iii, 250; grasslands and cattle, xiv, 222-3; mining products, iii, 360, 361, 364, 368 Montauk Point, birds at, xiii, 342 Mont Cenis Tunnel, xiv, 240, 241; drills used, i, 27 Montenegro, mountaineers of, xiv, 243 Monte Nuovo, eruption of, xiv, 316, 320 Montpellier, University, x, 36, 38 Montreal, harbor of, xiv, 270 Moodus, Conn., brontides, i, 196, 360 Moon, ii, 193-205; acceleration of, iv, 98; atmosphere, ii, 200, 204, 232; coronas, i, 183; distance, ii, 64, 197-8; earthshine on, 41; eclipses, 32, 206-8; erratic amplitude, 25; falling motion, 64, 65; Galileo's studies, 54, 96, xvi, 103; Halley on motions of, ii, 87; halos, i, 100, 103, 178, 180, 181; Hevelius's studies, ii, 57; influences of, 201; irregularities in motions, 32, 34, 73-4; life on, 204-5, 247; light and heat of, 168, 200; light of, Egyptian knowledge, xvi, 69; non-rotation theory, ii, 376, 377; path around earth, xiv, 292-3; photographic studies, ii, 130; quartering, 28, 194-5; size, 198-9, 230; size as observed by ancients, 27-8, 32; solar corona and, 221, 222; spectrum lines, 112; stereograms of, xi, 181; telescopic views of, iv, 346; theories of origin, ii, 375-6; tides caused by, 70; tides caused by, xiv, 291, 292-3 Moonbeams, measurement of heat of, iv, 301 Moon Dogs, i, 180, 377 Moon-Pillar, i, 376 Moonstone, iii, 329 Moor Fires, i, 56 Moors, astronomy of, ii, 11, 38; in Mediterranean group, xvi, 49; medical influence of, x, 37-8; science of, xvi, 100, 106 Moose, xii, 318-19; antlers of, 316 Moraines, iii, 67-8, 380, xiv, 59; lakes formed by, iii, 144-6, xiv, 202 Morality, beginnings of, xv, 356; civilization and, xvi, 43-4, 45, 47-8; primitive, limited to tribes, xv, 374; religion and, 355-7; varying conceptions of, 285-6 Morgagni Giovanni, x, 97-8 Moriceau, François, x, 79, 80 Morning Glories, climbing stems, xiii, 27; roots, 18; tendrils, 111 Moro, Lazzaro, xvi, 126 Morphine, xiii, 253; an alkaloid, viii, 240; use of, in pain, x, 381 Morro Velho, mine shaft, v, 259-60 Morse, S. F. B., telegraph inventor, vi, 24, vii, 108, xvi, 188 Morse Systems, vii, 108, 109-11 Mortar, lime in, viii, 150 Mortar and Pestle, xv, 238 Mortars (military), v, 368 Mortmain, meaning, xi, 44 Morton, William, ether introduction, x, 124-5, xvi, 185 Mosaic Laws, medical importance of, x, 15 Mosasaurs, iii, 288, xii, 203 Moselle River, xiv, 89, 90, 165 Mosenthal's Test, x, 379 Mosquitoes, campaign against, x, 299-301; in fly family, xii, 120; kinds of, x, 156; malaria spread by, 154, 156-9, 299-301; singing of, cause, xii, 103; yellow fever and, x, 160, 161-2, 173 Moss Animals, xii, 46-7 Mosses, alternation of generations, xvi, 166; character and kinds, xiii, 68-70; reproductive process, 160-3 Mosso, Prof., experiment of, xi, 285; on mountain sickness, i, 328 "Mother Carey's Chickens", xii, 252 Mother-Family, xv, 295 Mother-of-Pearl, xii, 63; iridescence of, 245 Mother Shipton, iv, 104 Mothers, rule of, under polyandry, xv, 294-5; transmission of hereditary traits, ix, 340-1; transmission of nervous influences, 343-4 Mother's Milk, infants' digestion of, ix, 346 Moths, xii, 114-16, 118-20; appearance in Tertiary, 104; evolution of, 107; in flower fertilization, xiii, 142-3; number of species in New York, xii, 99; Pronuba, adaptation in, xvi, 152-3 Motion, as sign of life, ix, 9-11, 14; bodily, different kinds of, 82-3; of animals, means of, 73-4; sense of, ix, 90, xi, 123-8 (see also Movement) Motion (mechanics), energy of (see Kinetic Energy); force in relation to, iv, 56-69, 71-2, v, 182-3; forms of, iv, 85-6; Galileo's investigations, iv, 19; laws of (see Newton's Laws of Motion); quantity of, iv, 62; rapid, not explained by Newton's theory, ii, 80, 81; relativity of, iv, 16-17, xvi, 85; science of, iv, 25; time and, Newton on, 15; uniform and difform, ii, 80; Zeno's theories, xvi, 84-5 Motor Cycles, cooling of cylinders, v, 160; gyroscopic action, 343; generators in, vi, 215-16 Motor-Generator Sets, vi, 332-3, 342-3; efficiency in electric furnaces, vii, 306 Motor-mindedness, xi, 222 Motor Nerve Cells, ix, 125, 126, 129, 160; connections, 130 (fig.), 131, 147, 148 (fig.) Motor Nerves, at birth, ix, 348 Motor Neurones, xi, 21, 22, 24; development in embryo, 34, 35 Motor Response, defined, xi, 123-4; method of, 26-7; sensation dependent on, 27-8, 43, 63, 66, 74-5, 102-3, 110-11, 118-21, 202-3; to contact and distance senses, ix, 95, 121, 140; violence in emotions, xi, 134 (see also Final Common Path, Reactions, Reflex Actions) Motors, iv, 308-9, vi, 217-63, vii, 367, 373; advantages over engines, 223; air-driven, v, 129-30; alternating-current, vi, 240-63; automatic regulation, 218, 224-9, 232; automobile, v, 156-61; compressed-air effects, 128; compression and non-compression, 157; constant-speed, vi, 231; direct-current, 217-39; direction of revolutions, 56; earliest form, 21; efficiency, 228; efficiency in cold weather, vii, 194; electromagnetic, vi, 95-6; for farm purposes, vii, 223-4, 225-6, 228; heat, Clausius's principle, xvi, 135; individual machine, vii, 52; in household appliances, 74, 78, 83-4, 86; interchangeability with dynamos, iv, 54; multiple cylinder, v, 159; of electric cars, vii, 182-3, 185, 186; of electric locomotives, 196, 200; popular applications of, iv, 10; power, on what dependent, vi, 223; ratings, 192-4; self-regulation of voltage, 226-8; single-cylinder, v, 157; speed variation and constancy, vi, 240-1; starting and starters, 235-9, 250-5, 262-3; synchronous, 241; three-phase system, 206-7; torque of, iv, 309, vi, 224-7; toy, 95-9; voltage generated, 247; water and air-cooled, v, 159-61; waterproof in U. S. Navy, vii, 332 Motor Tractors, v, 214, 215-218, 243 Motor Trucks, v, 214; advantages to farmers, vii, 231; growing use, 195 Motor Type of Men, xi, 155, 157, 158-9 Mott, Valentine, x, 121-2 Motus Peculiaris, ii, 346 Mound Builders, weaving of, xv, 248 (fig.) Mountain-and-Valley Breezes, i, 131, 132, 377 Mountain Goats, xii, 325 Mountain Health Resorts, i, 322 Mountain Lions, xii, 363 Mountain Observatories, ii, 139-51 Mountain Passes, formation of, xiv, 58, 176 Mountains, Mountain Ranges, xiv, 224-6; atmospheric pressure on, i, 28, iv, 114-15, 170, ii, 245; block, iii, 138-9, xiv, 117, 226; boiling point of water on, viii, 303; Brocken specters, i, 184-5; cirques of corries on, xiv, 58; civilization of, xv, 129-31; cloud caps and banners, i, 104-5; coast lines and, xiv, 248, 249; distinguished from plateaus, 28; economic importance, 237-9, 245; ephemeral character, iii, 11, 12, 130, xiv, 235; faulted, iii, 138-9, xiv, 226; folded, iii, 131-8, xiv, 36, 93-4, 96, 226-34; forests on, xiv, 238-9; formed by erosion of plateaus, iii, 139-40, xiv, 225, 226; formation complex, iii, 140-1; granite cores of, 112, xiv, 110-11; heights determined by barometers, 124; hot springs of, 143; igneous intrusions, 228, 230, 232-3, 234; influence of, on human history, 10, 236-45, xv, 136, 137-8; lightning dangers, i, 156; making of in various eras, iii, 187-91, 205-6, 213-14, 218-19, 224-6; metamorphism in, xiv, 234; old and young, 235-6; ores and mines, 234, 237-8; peoples of, 245, xv, 129-31; plants and animals of, xiii, 321, 381, xiv, 365-6, 370, 376-7; rainfall and, i, 111, xiv, 354-5; rime on, i, 121-2; rock weathering on, iii, 23, 24, xiv, 40, 233-4; ruggedness due to erosion, 234; St. Elmo's Fire, i, 157; shadows in sky, 169-70; snow-line on, iv, 183-4; solar radiation on, i, 210; sound intensity on, 186; structural topography of, xiv, 94; stunted trees, xiii, 367; temperature on high, i, 19; volcanic, iii, 139, xiv, 225-6, 327 (see also Volcanic Cones); weighing of, ii, 68-9; wind types, i, 132-3 Mountain Sickness, i, 328, ii, 144, 150 Mountain Streams, harnessing of, v, 79-81; material transported by, xiv, 52, 233-4 Mountain Systems, xiv, 227 Mount Wilson Observatory, ii, 147-8; program and equipment, 152-61 Mouse-hunter (weasel), xii, 349 Mousterian Implements, xv, 100, 105, 107-8 Mouth, cavity as resonance chamber, iv, 232; dryness of, in fear, ix, 166; germs in, x, 201, 202, 219, 289; grasping organ, ix, 82; opening of, in concussions, xi, 101; "watering" of, cause, ix, 165 Movement, perceptions of, xi, 165, 166, 170-1, 184, 185 (see also Motion) Moving Bodies, deflection by earth's rotation, i, 124-5, xiv, 32, 348; old theory of, ii, 63 Moving Pictures, iv, 347-9; business men and, xi, 340; color reproduction in, iv, 369; facial expressions in, xv, 63; of eclipses, ii, 212 Moving Picture Machines, v, 329-31; mercury arc rectifiers in, vi, 333 Moving Star Clusters, ii, 341-4, 379 Mozambique Channel, xiv, 273 Mudfish, xii, 152 Mud Hens, xii, 262 Mud Puppy, xii, 171 Mufflers, automobile, v, 165 Mulberry Tree, fruit, xiii, 55, 226; paper from, v, 290 Mule Killers, xii, 167 Mullein, hairy covering, xiii, 105 Müller, Johann (1801-58), x, 117-18; pupils of, 118, 127, 128, 131 Müller, Johann, ii, 13 (see Regiomontanus) Multiple Proportions, law of, viii, 110 Multiplex Telegraphy, vi, 87, vii, 112-18, 373 Mummies, Egyptian, linen wrappings of, xv, 243; scars of tuberculosis in, x, 290; wheat grains found with, ix, 17, xiii, 211 Muriatic Acid, viii, 87 Murrayville Well, iii, 355 Muscle-and-Joint Sense, ix, 80, 90-1, 153 Muscle Cells, ix, 74-5; action of, 78-9; fatigue in, 81; number unchanging, 48, 348 Muscles, action of, ix, 77-9; action in posture, 83-4; adrenalin effects, 171, xi, 273; at birth, ix, 348; blood supply, how controlled, 216-17, 220; blood supply in emotion, xi, 136-7; cell constitution of, ix, 22 (See Muscle Cells); communication with sense organs, 19-20, 122, 124, 137, 139, 140; connection with nervous system, 124-37, xi, 19, 20, 24; control of, by brain, ix, 139-40, 141, 147, 148 (fig.); cramps in, 313; development and overdevelopment, x, 304; development in embryo, xi, 34, 35; efficiency of, ix, 296; energy release and restoration, xi, 24-5; exercise effects, x, 270, 303; fatigue in, 247, xi, 271, 273-4, ix, 79-81, 83-4; fear and anger effects on, 166-7, xi, 132, 133; flexibility and tensions, effects, 337, 339-40, 371, 372, 374; flexion strength, 41-2; flexors and extensors, 54, 166, 262-3, ix, 76-7; force of, 75; functions in kinetic system, xi, 60; fundamental purposes of, ix, 86; injuries to tissues, 287, 348; irritability of, x, 87; mechanical action of, 71-2; kinaesthetic sensations from, xi, 123-8; kinds of, ix, 74-5; metabolism of, measurement in calories, 296, 297; motion sense in, 90-1; origin from coelom, xii, 27; pain in relation to, xi, 118-21; range of effort, ix, 79; reciprocal innervation, xi, 86; responses (see Motor Response); response to contact & distance sensations, ix, 95, 121, 140; soreness of, 80-1; strength and capacity, on what dependent, 75-6, 79; structure, 75; thickness and length, 75-6; uses, different kinds of, 82-4; wasted in starvation, 297-8 (see also Heart Muscle, Skeletal Muscles, Smooth Muscles) Muscle (Muscular) Senses, ix, 90-1, xi, 63, 64; in infants, ix, 350; organs of, 125 Muscular Motion, electricity from, vi, 16-17, 63-4 Mushrooms, character of, xiii, 43, 70; origin, 223; reproductive processes, 163-5 Music, fatigue diminished by, x, 247; Hawaiian, xv, 315; light transformed to, v, 332-5; pitch modulations in, iv, 209; primitive, xv, 312-15 Musical Chords, xi, 106-8 Musical Insects, xii, 109-10 Musical Instruments, development of, xv, 315-18, 325; quality differences, iv, 233; reed mouthpieces, 234-5; stringed, 222-4; wind, 231 Musical Scale, iv, 206-9, xi, 105-6; tones in Indian, xv, 314 Musical Terms, from Italian, xv, 161 Musk, source of, xii, 322; spread of odor of, iv, 131, xi, 80 Musk Deer, xii, 322 Muskox, xii, 328; in glacial period, xiv, 376 Muskrats, xii, 289, 290 Mussels, xii, 58-67; in lakes, xiv, 211-12 Mustangs, xii, 307 Mustard, effects on stomach, ix, 243-4; origin, xiii, 265 Mustard Family, xiii, 197 Mustard Gas, viii, 263, 264, x, 187 Mustard Plant, fruit, xiii, 57 (fig.); leaf, 38 Mustard Seed, xiii, 60 Mutants, Mutation, ix, 342-3, xiii, 333-4, xv, 23-4, xvi, 155 Mutilations, of body, xv, 257-60; regeneration of, xii, 170 Muybridge, Edward, v, 330 Myer, Gen. Albert J., i, 217, 220 Myopia, ix, 112 Myotomes, xi, 34, 35 Myrtles, antiquity, xiii, 324-5 Mythology, beginnings of, xv, 357-8 Myxedema, x, 272, 349-50, 351 Nacre, xii, 59 Naias, fertilization, xiii, 151-2 Naids (Naidae) xii, 53-5, 65-6 Nails, former making of, by smiths, iv, 49 Nails (body) cells of, ix, 13 Names, and perceptions, xi, 160-1 Naphthalene, viii, 51, 240, 253 Napier, John, logarithm invention, xvi, 104 Naples, Bay of, crustal movements about, iii, 80-1 Napoleon, dissolution of Salerno University, x, 36; Egyptian campaign, mirage, i, 172; indigestion before Waterloo, ix, 238; Italian campaign, xiv, 244; military road over Alps, 241; Russian campaign, i, 306-7; vaccination order, x, 102-3 Napoleon III, brain weight, xv, 39 Narragansett Bay, oysters of, xii, 61; scallop fisheries, 65 Narrow-mindedness, muscular causes, xi, 372; of grinds and thrill-hunters, 376 Narwhales, xii, 297 Nassa, xii, 70 Nassir Eddin, ii, 39 Nasturtium, leaves, xiii, 33 (fig.); roots, 16 (fig.); water-dripping by, 108 Natal, forests and grasslands, xiii, 375, 376; hailstorm, i, 119 Naticas (mollusks), xii, 73 Native Shrubs, advantages, xiii, 273; planting table, 274-89 Natural Bridges, iii, 127 (fig.), 128 Natural Gas, iii, 354; composition, viii, 208; exhaustion of supply, v, 173; found with petroleum, iii, 350-3, 354, 355; low luminosity, viii, 60; origin and occurrence, iii, 354-5; waste, 355 Natural History School, of medicine, x, 113 Naturalism, development, xvi, 111, 115 Natural Sciences, xvi, 139-48 Natural Selection, x, 135, 136, xv, 23, 24, xvi, 150-1, 152; disease and, xv, 48; in man, xv, 47-8; working of, xii, 293, xiii, 334-5, 346, xv, 24-5 (see also Struggle for Existence, Survival of Fittest) Nature, actions of, former theories, iv, 18-19, 26; complexity and interdependence in, xv, 22; curative powers, of, x, 21, 73, 75-6, 84-5, 367, vii, 240; cycles in, viii, 349; efficiency of, vi, 96; life-renewing instinct, xiii, 116-17; Longfellow's lines, xvi, 43; man and, contrasted by language, xi, 224; personification of, xv, 357; prodigality (see Prodigality of Nature); savage attitude toward, xv, 321, 329, 331, 339; science and the forces of, vii, 235 Nature-Philosophy School, x, 113 Naunyn, Bernard, xvi, 184 Nausea, ix, 91; cause of, xi, 39; visceral sense, 63 Nautical Almanacs, ii, 13, 40, 216, 263; of Greenwich, xvi, 125 Nautilus, pearly, iii, 273-5, xii, 75-6 "Nautilus," submarine, v, 198 Navajo Indians, weaving of, xv, 247 (fig.) Naval Architecture, problems of, v, 194 Naval Warfare, projectiles in, v, 373 Navigation, chronometers in former, v, 66; historical development, 182, 188-9, xv, 261-5; meteorology in, i, 271-83; wireless applications, vii, 284-5 Neanderthal Cave, xv, 95 (fig.) Neanderthal Man, xv, 96-8; disappearance of, 99; implements of, 107, 108; period of, iii, 302, xv, 102; skull of, iii, 304 (fig.) Neap Tides, ii, 70, xiv, 292 Nearsightedness, ix, 112, xi, 85 Nebraska, potash supplies, viii, 279, xiv, 67; volcanic ash deposits, 327; water beneath, iii, 114 Nebulæ, ii, 357-60; distribution, 352; double, 377; Herschel's conception, 16, 368-9; in connection with new stars, 332, 333; in relation to Galaxy, 355, 364-5; in relation to stars, 308-9, 365, 381; motions, 364; photographic study, 135-7; spectra, 116; types, ring and spiral, iii, 160-1 (see also Spiral Nebulæ) Nebular Hypothesis, ii, 367-72, 374-5, 380, iii, 159-61; anticipated by Swedenborg, ii, 367; applied to asteroids, 258; in relation to earth's heat, iii, 108, 178, 184-5 Nebulium, ii, 359 Neck, arteries of, ix, 196-7; pulse in, 311 Necropsies, x, 98 Nectar, of flowers, xiii, 124, 125 Needles, primitive, xv, 81; threading of, ix, 118 Negative, electrical meaning, vi, 57, 124 Negative Electricity, i, 141, 142, iv, 258, 265, vi, 287, 288; electrons as, viii, 187-8; in atmosphere, i, 143 Negroes, color of skin, xv, 36; hair of, 38; in Tropics, xiv, 356; in U. S., 218-19; language of, xv, 159; nose index and nostril shape, 46; prepotency in crosses, x, 230; susceptibility to lung diseases, xv, 50; type characteristics, 35 (see also Black Race) Negroes (African), belief in Reincarnation, xv, 334; idea of soul, 330; ideas of sleep, 332; priests of, 350-1 Nematodes, xii, 45 Neodymium, atomic weight and symbol, viii, 383 Neolithic Period, domestic animals of, xii, 346; implements of, iii, 302, 306, v, 14, xv, 103, 109-10 Neon, in atmosphere, i, 11, 12; production and use, i, 33; symbol and atomic weight, viii, 383 Neotomy, xii, 173 Nephoscope, i, 86, 377 Neptune (planet), ii, 268-9; atmosphere, 250; comet families, 271; discovery, 67, 79, 86, 189, 268, 272; distance from sun, iii, 159; habitability, ii, 250; orbit, 270, 163; photographic study, 133; planets beyond, 270-3; retrograding motion, 271; size, 163; rotation period, 377; weight, 77 Nerve Cells, functions and structure, ix, 122-4, 125; growth of, 48; of brain, 140 (see also Connective, Motor and Sensory Nerve Cells) Nerve Centers, of brain stem, ix, 168, 257 Nerves, color effects, vi, 274-5; at birth, ix, 348-9; composition and color, 124, 159-60, xi, 17; cranial, 29-31 (see Cranial Nerves), ix, 131, 132; distribution to muscles, 124-5, 127; electrical excitation, vi, 63-4; spinal, ix, 131-2, xi, 25-6; to glands and smooth muscles, ix, 159-60, 162, 164-5 (see also Nerve Cells, Neurones) Nerve Trunks, ix, 131-2 Nervous Actions, complex, ix, 139-54; simple, 132-7; special, 155-72 Nervous Activity, fundamental laws, xi, 18-23, 27-8 Nervous Diseases, electrical treatment, vi, 17, 63-4, 284-5; electrical treatment, vii, 235, 238-9; habit in, xi, 248; hot baths in, x, 311; physical attendants, 353; physical causes, xi, 370-2; suppressed emotions and, 140 Nervous Fatigue, ix, 137-8 Nervous Fluid Theory, x, 85-6 Nervous Prostration, x, 248 Nervous System, xi, 16-32, ix, 122-38; brain connections in, ix, 142-4, 147-51; complexity and mental activity, xi, 13, 20; control of body functions by, x, 346-7, 352-3; control of glands and smooth muscles by, ix, 159-60, 162-3, 164-5, 168; development in embryo, 343, 344, 348-9, xi, 34-6; emergency effects on, ix, 166-7, 171; examination methods, x, 371; fatigue effects, xi, 272, 274; function (Crile), 58; functional unit, 20; habit in, 248; hereditary diseases of, x, 234; in sleep, xi, 286-8; part of, in maintaining life, ix, 20, 21, 23; reciprocal innervation in, xi, 86; sympathetic, x, 352-3, xi, 134-5; thyroid effects on, ix, 303, 304 (see also Central Nervous System) Net Goods, v, 277 Netherlands, delta formation of, xiv, 186 Nettle, hairs of, xiii, 42 Net-veined Leaves, xiii, 32, 34, 176, 178, 183 (fig.); classification of plants with, 60-1 Networks, electric, vii, 27, 373 Neuralgia, barometric effects, i, 329 Neurasthenic Abscess, Amatus' cure of, x, 58-9 Neurones, xi, 17-18, 20-1, 22 (see also Nerve Cells) Neurotomes, xi, 34, 35 Neutral Coasts, xiv, 248, 254, 263-4 Nevada, mining products, iii, 366, 368, 370; "pogonip" fogs, i, 96; rainfall, 112; silver mines, viii, 198; topography, xiv, 42 Névé, granulated snow, iii, 59 New Brunswick, N. J., radio plant, vii, 274-5 Newcomen's Engine, v, 144, xvi, 125 New England, agriculture and manufacturing in, xv, 132; building stones, iii, 371, 372; clock making, v, 50; cod fisheries, xii, 164; cotton mills, xiii, 236; "dark days", i, 56-7; forest trees of, xiv, 372; geological history, iii, 219, 231-2, 234, 235, 240; glacial bowlders, 70, xiv, 59; glacial soil of, 70; glacial topography, 56, 60; gorges, iii, 44; igneous rock formations, xiv, 111, 112; January thaws, i, 363, 376; Labrador current effects, xiv, 305; lakes of, 200; mussels on coast, xii, 65; opossums in, 275; peneplain of southern, iii, 35; plateau of southern, xiv, 216-17, 221, 236; "Vineland" as, 261; water power and manufactures, 31 Newfoundland Banks, cod fisheries of, xii, 164; fogs, i, 93-4, 94, xiv, 305 (see also Grand Banks) New Guinea, animals of, xii, 249, 272, 279; bird of paradise of, xv, 275; cockatoo of, v, 9-10; continental island, xiv, 276; rain forests of, 369 New Jersey, coast of, xiv, 256, 262, 263; coast destruction, 45, 302; coastal plain water supply, 138; dunes on coast, iii, 71; former copper mines, xiv, 112; former volcanoes, 318; igneous rock formations in, 107, 111, 112; pine barrens, xiii, 371; silk industry of, xiv, 269; streams of southern, 160; zinc production, iii, 363, 364 New Madrid Earthquake, iii, 95, 98 Newman, Cardinal, on change, xiii, 325-6, 336 New Mexico, arid topography of, xiv, 42; mesas of, 82; volcanic fields of, 102, 315, 317, 318; wife auctioning by Indians, xv, 283-4 "New Mexico" (battleship), electrical operation, vii, 327-8; induction motors, vi, 248 New Orleans, acquisition of, xiv, 193; founding of, 192; growth, 219; harbor of, 270; yellow fever epidemic, x, 160 New Orleans Inner Harbor Canal, v, 259 Newspapers, printing and presses, v, 301-5, 306; typesetting by machine, 307-8 Newsprint, making of, v, 292, 298 New Stars (see Novae) New Testament, sounding lines mentioned in, xiv, 284 Newton, Sir Isaac, ii, 14, 62, iv, 19-20; forerunners of, ii, 58-9; gravitation discovery and laws, 63-72, iv, 20, 95-8, xvi, 115-16; Halley and, ii, 88; influence of, on mechanics, iv, 11; laws of motion, ii, 62-3 (see Newton's Laws); light experiments, ii, 111, iv, 357, xvi, 119; light theory of, iv, 47; mathematical work, ii, 14-15, xvi, 115-16; methods, ii, 71; on comets, 85; on conservation of energy, xvi, 131; on mountain observatories, ii, 139, 140; on precession, 70-1; on refracting telescopes, 100, 140; on shape of earth, 69; on tides, 70; on time, iv, 15; on what gravitation is, ii, 78; "Principia", 13, 63, 67-8, 88, xvi, 105, 115; sound velocity law, iv, 198; telescopes, ii, 102, 103 Newton's Laws of Motion, ii, 62-3, 66, iv, 61-9; anticipated by Galileo, ii, 56, iv, 19; applicability, 86; based on absolute space and time, 16, 18; discovered under apple tree, v, 109 Newts, xii, 169, 170-3 New Vienna School, x, 113 New York (City), Beach's subway, v, 138; Broadway lighting, vii, 340-1; croton bugs of, xii, 107; Croton Dam, iv, 119; crowds after Lincoln's death, xi, 323; Edison system, vi, 151, xvi, 188; five-cent fare, vii, 198; garbage value, viii, 330; geological changes around, iii, 78, 79; growth, to what due, xiv, 267-8; "hobble-skirt" cars, vii, 184; insects around, xii, 99; magnetism of earth at, iv, 247, 249, 250, 252; Penn. R. R. station, xiv, 146; region west of, iii, 211 (fig.); sewage disposal, viii, 325; submachine guns for police, v, 368; subway excavating, 261; subways, air-brake system, 132-3; subways, dust, i, 325; subways, electrolytic corrosion, vi, 66; synchronized electric service, 384; telephone connections with Los Angeles, 367-8; telephone exchanges, vii, 103; telephones in, 75; telephones, automatic, vi, 87, vii, 92, 106; temperature range, xiv, 346; terminals electrified, vi, 162, vii, 181-2, 193-4; underground wire systems, 12, 14, 24; water supply, viii, 317, xiv, 140; weathering in climate of, iii, 23; wireless device in Times Square, vii, 280 New York Harbor, developing shore lines, iii, 58; dredging of Ambrose Channel, v, 257-8; formation of, xiv, 255, 268; lighterage conditions, 266-7; sedimentary deposits, 268-9; wireless piloting, vii, 284-5 New York (State), drumlins, iii, 69, xiv, 60; finger lakes, 203, 211; forest trees of, 372; geological history, iii, 195-6, 231-2, 234-5, 219, 240, 243-5; glacial bowlders, 70; glacial soil of, xiv, 70; glacial topography, 56, 60, 61; gorges, iii, 44, 243, xiv, 50, 52, 171-2, xiv, 50, 52, 171-2; gypsum deposits, iii, 376; lakes, how formed, 143-4, 145; lakes, number, xiv, 200; oyster industry, xii, 61; salt deposits, iii, 375, viii, 140; weather observations, organized, i, 215 New Zealand, coasts, xiv, 258, 264; geological history, 275-6; Maori of (see Maori); native carvings in, xv, 300; ratite birds of, xii, 249; sheep plant, xiii, 379; sheep-raising in, xiv, 384; snakes absent from, xii, 217; spinach in, xiii, 224; travertine terraces, xiv, 146; tuatera of, xii, 183-4 Niagara Falls, electric furnace industries at, vii, 302; harnessing of, vi, 368-70; origin and history, iii, 45-7, 243; rate of recession, 246; verticality due to undermining, xiv, 133; working power, vi, 47 Niagara Falls Power Plant, vi, 368-78; load factor and charges, 381; phased with Canadian plant, 384 Niagara Limestone, iii, 192 Niagara River, drop in, vi, 368; due to Ice Age, iii, 243; first impressiveness, vii, 202; gorge of, xiv, 51 "Niagaras," Electric, i, 342, 343-4 Nickel, viii, 126-7, 154; affinity strength, 128; atomic weight and symbol, 383; classification place, 178, 183; electrical conductivity, iv, 283, vi, 77; fusibility, viii, 384; in earth's interior, xiv, 11; in steel alloys, xiv, 238; magnetic susceptibility, iv, 251; melting point and requirements, iv, 162; ores of, viii, 198, 270; positiveness, vi, 59; source, xiv, 238; test for, viii, 287, 289 Nickel-Iron Batteries, vi, 149-51 Nickel Plating, vii, 314, 316-17 Nicol's Prism, iv, 354 Nieve Penitente, i, 117, 377 Niger River, furrow of, xiv, 287; Park's explorations, xvi, 123 Night, cooling of earth at, i, 121; "falling" of, xi, 173; plant conduct at, xiii, 88-9, 113, 114, 126 Night Adders, xii, 232 Night-Blooming Plants, fertilization, xiii, 152-3 Nightingales, xii, 269 Nightjar Family, xii, 267 Nightshade, xiii, 250 Nile River, aerial photography, i, 46-7; ancient harnessing, v, 19; annual overflow of, xiv, 53, 70-1; bichir of, xii, 151; Bruce's exploration, xvi, 123; connections with Congo system, xiv, 186-7; course of, 120, 155; crocodiles of, xii, 199; dominance of Egyptian life, ii, 26; Egypt gift of, xiv, 71; gobar of upper region, i, 96; hippopotamus of, xii, 310; length and volume, xiv, 189; rafts used on, xv, 264-5; veneration in Egypt, v, 18; water supply of, xiv, 182-3 Nile Valley, antiquity of man in, xv, 84; fertility, xiv, 71; sand-abrasion of granite bluffs, 77 Nimbus Clouds, i, 98, 101, 103, 377 Ninevah, burying of, iii, 75 Ninevah Eclipse, ii, 209 Nipissing Lakes, iii, 150, 151 Nirvana, xv, 334 Niton, viii, 185; atomic weight and symbol, 383; in atmosphere, i, 11, 12 Nitrate Group, viii, 93; in explosives, 71 Nitrates, cellulose forms, viii, 254-5; Chilian deposits, i, 35; viii, 64, 197, xiv, 66; commercial production, i, 35-6, vii, 322, 323-4, viii, 74; formation in soil, i, 35, viii, 340, 345, xiii, 98; metal occurrence in, viii, 130; test, 290; uses, 72; arterial spasm, x, 381 (see also Potassium, Silver, Sodium Nitrates) Nitric Acid, character and uses, viii, 71-3, 115, 116; in atmosphere, i, 13; production of, 36, vii, 322, 323-4, viii, 74, 137, 275; solubility, 112; strength, 115 Nitro, defined, viii, 379 Nitrocellulose, viii, 255, 256, 261 Nitro Compounds, viii, 237; in explosives, 71 Nitrogen, viii, 18, 64-8; agricultural needs and sources, i, 34, vii, 321, viii, 73-4, 75, 280, 340, 341, 343, 345-6, xiv, 64-5, 66; atmospheric, i, 10, 11, 34, vii, 321-2, viii, 67; atomic weight and symbol, 383; boiling and freezing points, iv, 173; chemical inertness, i, 12-13; critical temperature, 29, iv, 173; derivatives, viii, 229-30 (see also Amines); elimination from body, 353-4, x, 342; fixation, natural and artificial, i, 13, 33, 34-7, 153, vii, 301, 321-4, 352-3, viii, 66, 73-5, 153, 345-6, x, 193-4, xiii, 98, xiv, 66, xvi, 165; freed by combustion and decay, viii, 61, 330, 345-6; in blood effects, i, 329, v, 120, x, 346; in chlorophyll, xiii, 80; in explosives, viii, 63, 345-6; in garbage, 330; in proteins, 64-5, 340, 351, ix, 29, 279, 282, 284, x, 270, 277; industrial uses, i, 33, 34; liquefaction of, iv, 171; melting point, 162; preparation from air, viii, 65-6; production from liquid air, i, 30, 32, 34, viii, 67, 68, 274; solubility in water, 40, 111; spectrum of, i, 161 Nitrogen Compounds, viii, 64, 68-74; by-products of coke, 46-7; in air, i, 13; in animal body, viii, 353-4; instability, 66; organic, 229-30; vitamines, 369 Nitrogen Cycle, viii, 73, 334, 335, 349; practical applications, 325-6, 330, 340, 345-6 Nitrogenous Waste, x, 270 Nitroglycerine, viii, 63, 247-8, 260, 261 Nitrous Acid, viii, 115; in atmosphere, i, 13; production, 36 Nitrous Oxide, viii, 70-1; as anesthetic, x, 123-4; critical temperature and pressure, iv, 172 Nobody Crabs, xii, 89 Noctilucent Clouds, i, 17-18, 58, 377 Nodes, of moon, ii, 197 Nodes, of vibrations, iv, 217 Noguchi, Hideyo, x, 173 Noises, awe roused by, xi, 147; qualities of, 104 Nomadic Life, xv, 128, xiv, 141 Nonconductors, (electrical) iv, 259, vi, 77, 294, vii, 373; nonmetals as, viii, 126 Nonmetals, viii, 17-19, 84, 126, 379; in body tissues, 354; manufacture and uses, 274-5; negative ionization, 122; oxides of, 20, 39; periodic classification, 181; plants needs of, 337, 341; tests, 289-90; union with metals, 20, 32 Nordic Group, xvi, 48-9, 50 Norfolk, Va., harbor of, xiv, 268 Noria, ancient use of, v, 19 Normals, meteorological, i, 204, 378 North Africa, civet cat of, vii, 353; civilization in, xiv, 196; mormoids of, xii, 154; vultures of, 260; zoölogy of, xiv, 291 North America, ancient camels of, xii, 313; animals (carnivora), 340, 342-3, 349; birds of, 268-9; climate of eastern, xiv, 346-7; climate on opposite coasts, 345; coasts, Atlantic and Pacific, 25-6, 40, 247-8, 249-50; cyclones and tornadoes, i, 137; drainage systems, xiv, 190; exploration and settlement, 196-7, 310-11; forests of, 371, 372-4, 375-6; former connection with Asia, xii, 313, xiii, 351, xiv, 30; former connection with Europe, 290; frogs of, xii, 180; fur animals of, 350; geological history, iii, 164-248; Ice Age and resulting topography, 62, 236-48, xiv, 3, 30, 43, 59-62, 200, xv, 74-6; indigenous plants, xiv, 382; no absolute deserts in, xiii, 377; Northmen in, xiv, 261; rainfall of, 360; rivers in history, 31, 190-5, 196-7; snails of, xii, 69, 71; tobacco used by natives, xiii, 256; trees of, xiv, 375-7; Urodela of, xii, 170-2 North American Basin, xiv, 288-9 North Atlantic Ocean, birds of, xii, 251, 252, 253; currents of, xiv, 304; deep sea life in, xii, 23; formation of, xiv, 290; giant squids of, xii, 79-80; herring fisheries, 156; limacina of, 19; sharks of, 145, 146; temperature of, xiv, 297; walruses of, xii, 334; weather charts, i, 275, 276 North Beach, Florida, wave power at, xiv, 300 North Cape, level changes at, xiv, 34 North Carolina, Appalachian Mts. in, xiv, 97, 168; coast of, 264; thermal belts, i, 259; trap dikes of, xiv, 112-13 Northern Hemisphere, cradle of flowering plants, xiii, 319; deflection of motion in, i, 125; dip of magnetic needle in, iv, 245-6; forests of, xiv, 371; land in, 20; winds of, i, 125, 127, 128, 137, xiv, 345-6, 348 Northern Lights, i, 158 (see Aurora) Northmen, history of, xiv, 261-2 North Pole, rain at, i, 109 North Sea, commerce development in, xiv, 308; formation of, 287; formerly land, xv, 76; herring fisheries, xii, 156 Norway, barley ripening in, xiv, 365; civilization of, xv, 131; coasts, iii, 57, 79; coasts, xiv, 247, 258, 259 (see also Fjords); glaciers of, 55; Gulf Stream effects, 304; latitude of, 315; nitrogen fixation, i, 36, vii, 324, viii, 74; plain on west coast, xiv, 47 Nose, adaptation to odors, xi, 80; bones of, ix, 62; cartilage in, 57; cleanings of, x, 312; cold effects on, ix, 311; functions and diseases of, x, 341; germ infection through, 198, 202, 219; in infants, xv, 61; nerve connections, xi, 81-2; organ of smell, 62, 78; passages, 77; plastic surgery of, x, 57, 189; racial types, xv, 45-6; smell organs in, ix, 96; violent blowing, danger, xi, 101; X-ray examinations of, x, 373 Nose Rings, xv, 259 (fig.), 260 Nostrils, of monkeys, xii, 376; racial shapes of, xv, 46 Notes, musical, iv, 206-9, xi, 105-6; of Indian scale, xv, 311; pitch and intervals, iv, 205-6, ix, 99-100; pitch changes by motion, iv, 210; quality of, to what due, 233 Notochord, xii, 128; in lancelets, 129 Novae, or New Stars, ii, 331-3; explanation, 329; in class of variables, 324; location, 328; outbursts, 328-9 Nova Scotia, coal beds, iii, 199; Vineland as, xiv, 261 Nuclei, chemical, xvi, 162 Nuggets, iii, 367 Numbers, development of systems of, xv, 180-4; Pythagorean theory, xvi, 80 Numerals, Arabic, xvi, 103; Babylonian, 60-1 Nummulites, iii, 235 Nut Butter, source, xiii, 10, 220 Nuthatches, xii, 268 Nutmeg, xiii, 261-2 Nutrition, chemistry of, viii, 348-72; defective, due to under-chewing, ix, 228; deficiency of, disease from, x, 255-68, 314; problem of, in therapy, 382; stimulated by light, 253 (see also Diet, Food) Nuts, food value, viii, 366; oil in, 246 Nymphs (aquatic larvæ), xii, 106 Oak-Hazel Copses, xiii, 369-70 Oak Trees, antiquity, xiii, 324-5; family, 193; fertilization, 148; flowers without petals, 190; index plants, i, 255; in American forests, xiv, 373; in Danish Peat bogs, xv, 87; in landscaping, xiii, 271-2; northern limit, 367; rate of increase of, xv, 19, 21 Oaths, judicial, xv, 373-4 Oats, food value, viii, 364; native of Old World, xiii, 182; vitamines in, x, 262 Obelisks, Egyptian, ii, 24 Obesity, x, 272-5 Obsequent Streams, xiv, 160, 174 Observatories, ancient, ii, 37, 38, 39; mountain, 139-51; first European, xvi, 100 Occupational Diseases, x, 244-6 Occupational Fatigue, xi, 270 Occupational Postures, xi, 371, 372 Ocean, Oceans, annual discharge of rivers into, xiv, 135; atmospheric conditions over, i, 13, 14, 143-4, vii, 212; basins and shoal water line, xiv, 24-6, 287-8; basins, topographical features, iii, 52, xiv, 27, 286-90; birds of, xii, 251-4, 258, 264; chemical elements in, xiii, 196-7; circulation of water in, xiv, 298-9, 303-5; color of, viii, 40; coloring, to what due, xii, 17, xvi, 147; density of water in, v, 195-6, xii, 21-2; deposits on floor, iii, 52-5, 168, xiv, 284-6; depths, iii, 51, xii, 21, xiii, 72, xiv, 23-4, 26-7, 288-9, 290 (see also Deep Sea); depths still a mystery, v, 202; divisions, xiv, 22; earthquakes in, 336-7; erosive work (see Ocean Waves); evaporation, vii, 212; exploration of, xiv, 283-4; extent of distribution, 20-3, iii, 51; faulting in bed of, xiv, 39; floors, general flatness, iii, 52, xiv, 24, 284; floor level changes, iii, 83, 168, 206, xiv, 34, 253; floors never land, iii, 55, xiv, 290; floor, ooze of, xii, 17-18; former extensions, iii, 12, 54, 55, 130, 132, 165-224 (maps), 235, xiii, 298-9, xiv, 19; heating and cooling of, 346; historical importance, 305-11; metals found in, viii, 148; meteorology of, i, 271-83; organic life of, xii, 16-24, xvi, 146-8; organic life in relation to salts, ix, 174, 175; phosphorescence of, xii, 18-20, 84; potassium compounds in, viii, 143, 279; power from, v, 174 (see Tides, Ocean Waves); pressure of water in, v, 95, 201; salinity, iii, 51-2, viii, 138-9, 195, 196, 279, xiv, 295-6; salt of early, ix, 175-6; soundings, xiv, 284; surface form and tides, 291-5; temperature layers, xii, 21-2, xiv, 297-9; theories of origin, iii, 160, 163; thunder audibility, i, 193; volcanoes in, xiv, 285-6; wind and pressure belts, i, 128-9; wind charts, 271-6 Ocean Commerce, development of, xiv, 305-11 Ocean Currents, xiv, 303-5; altering courses, i, 345; charts, 271-6; deflection by earth's rotation, xiv, 32; plant and animal distribution by, 277, 278; seed-dispersal by, xiii, 346-8 Oceanic Islands, xiv, 276-9; plants of, xiii, 348 Ocean Steamers, development, v, 192-4; strains on, 194; turbines in, 153-4 Ocean Waves, base level of erosion, xiv, 254; cause, 299; coast destruction by, iii, 55-7, xiv, 44, 45, 46, 299-303; length, vi, 269; motion, v, 124; power uses, 174; quelled by compressed air, 124-5 Ocelots, xii, 364 Octopus, xii, 77 Odorous Oils, in mint plants, xiii, 205 Odors, ix, 97; adaptation to, 97, xi, 80-1; agreeable, enjoyment of, ix, 98; classification, xi, 79; digestion and, x, 320; inhibition effects, xi, 81; perception of, ix, 96, 97; spread of, iv, 131 Odyssey, historic value of, xv, 323-4 Oersted, Hans Christian, vi, 19-20; electromagnetic discovery, iv, 276; on waterspouts, i, 356 Ogden River Canyon, iii, 39; thrust faults in, 92 Ohm, Dr. S. G., vi, 21-2 Ohm's Law, iv, 281-2, vi, 22, 74-5, vii, 373; applied in meter construction, 157-8; anticipated by Cavendish, vi, 17; for alternating currents, 164-5, 169-70 Ohmmeter, vi, 80 Ohms, electrical resistance unit, iv, 282, 284, vi, 71, 74-5, 170, 171, vii, 373; method of measuring, 165-6 (see Ohm's Law) Ohio, corn-crops and weather, i, 245-8; glacial drift in, xiv, 170 Ohio River, drainage changes, iii, 245; water supply and sewage, viii, 318 Ohio Valley, floods, i, 110-11 Oil, fuel on battleships, vii, 328; Crude (see Petroleum), films of, colors in, iv, 377; shark's, xii, 146-7; turtle, 194; use in lessening friction, v, 203 Oildag, vii, 300 Oil of Vitriol, iii, 336, viii, 83 Oil Pools, iii, 380 Oils, defined, viii, 244 Oils, Fatty, viii, 244, 245, 246, 247; as food, 363; hydrogenation of, 232, 247; insolubility, 112; preserving of, 371; vegetable (see Vegetable Oils) Oil Wells, drilling of, v, 265-7; from diatom deposits, ix, 28; gushers, iii, 353-4; productiveness and life of, 353 Okapi, xii, 321-2 Okeechobee, Lake, xiv, 200 Old Age, cause of degeneration in, x, 201; feelings of time in, xi, 194; jaws in, ix, 57 "Old Probabilities", i, 216-17 Old Testament, hygienic laws in, x, 15; morality of, xv, 374 Old Vienna School, x, 77, 104 Old Wives' Remedies, xiii, 249 Oleic Acid, viii, 221 Olfactory Nerve, ix, 142, xi, 29-30, 81-2 Oligoclase, iii, 329 Olive Oil, chemical nature, viii, 231; making of, by plants, ix, 28, xiii, 95; substitutes for, viii, 363 Olives, acquired taste for, xi, 72, 73; origin, xiii, 226 Olivine, iii, 334 Omega Centauri, ii, 136, 336-7, 338-9 Omens, belief in, xv, 355 Omicron Ceti, type of variables, ii, 324-5, 327 Onions, antiscurvy vitamines in, x, 266; bulb, xiii, 25 (fig.); in lily family, 184; origin, 223; underground, stems, 23 Ontario, glacial soil of, xiv, 70, 170; Keewatin series, iii, 169; lakes, 143; oldest fossils in, 250 Ontario, Lake, increasing altitude, iii, 82 Oozes, deep-sea, iii, 54, xii, 18, 19, xiv, 285 Opals, iii, 334-5 Opaque Bodies, iv, 324; X-ray examination, vii, 253-5 Open Hearth Furnaces, v, 320-2, 323 Open-Hearth Process, viii, 160, 269 Opium, history and sources, xiii, 253-4; use of, in tropics, xv, 126-7 Oppolzer, Johannes von, x, 113 Opossums, xii, 274-6, 278; embryological resemblances, xv, 54; instinct of, xi, 46 Optical Illusions, iv, 323, xi, 184-90; due to atmospheric refractions, i, 171-4, iv, 326-9 Optic Nerve, ix, 110 (fig.), 124, 142, xi, 29-30, 84-5; discovery, xvi, 82; retina and, iv, 346; stimuli affecting, x, 118 Optics, atmospheric, i, 164-85; "father of physiologic", x, 97; history of development, xvi, 101, 119 Optimal Temperature, xi, 51 Optophone, v, 332-5, 384 Orange (color), complementary color of, iv, 367; heat color, 361; soothing effects, vi, 274, 275 Orange Juice, for babies, ix, 347 Oranges, food values, x, 266, 268; origin, xiii, 226; spread, 354; true berries, 54 Orang-utan, xii, 381, 383; compared with man, xv, 59; of Bronx Garden, v, 9 Orators, advantages over writers, xv, 145; limited speeches of ancient, v, 62; pitch of voice of, iv, 232 Orchards, frost protection, i, 259, 332; warm and cold spots, 258-9 Orchestras, sounds of, iv, 199 Orchid Family, xiii, 184-7 Orchids, aerial roots, xiii, 20-1; butterfly, 145; epiphytic, 362; fertilization, 144-5; flowers, 50; highest of monocotyledons, 181; illustrations, 145-7; leaves of saprophytic, 100; Madagascar, 48; seeds, 154, 344; vanilla, 259-60; in tropical forests, xiv, 368 Ordeals, xv, 373 Ordovician Period, iii, 20, 185-91, 381; plants and animals, 251, 261, 266, 267, 268, 270, 273, 274, 277, 281; sea extensions in, 183 (fig.) Ore Deposits, iii, 355-70, viii, 197-200 Oregon, block mountains, iii, 139; earthquakes in, xiv, 331; forests of, 374; lava formations, 102, 104, 318; storm waves on coast, 300 Ores, defined, iii, 381, viii, 197; electrolytic refining, vii, 319-21; extraction of metals from, viii, 131, 269-72; in metamorphic rocks, xiv, 234, 237; veins, how formed, iii, 126 Oresme, Nicole, xvi, 101 Organic, defined, viii, 380 Organic Acids, viii, 52, 219-21, 336 Organic Chemical Industries, viii, 241-66 Organic Chemistry, viii, 52, 204-40; beginnings, xvi, 162 Organic Compounds, viii, 51-2, 204, 205; character of series, 207; colors, 85-6, 258, 312; explosion of, 63; interchange of groups, 211; physical state and molecular complexity, 298; solubility in water, 37 Organic Life, beauty universal, xvi, 145-6; climatic influences, 141-2; distinction from inorganic realm, xii, 13-14; origin, xiii, 300-1, xvi, 144-5, 149; no traces in meteors, ii, 292; studies of Mayer and Helmholtz, xvi, 142 (see also Life) Organic Liquids, solubility, viii, 112 Organic Matter, chemical constituents, viii, 18, 29, 34, 42, 64; food of animals, 349; formed by plants, xiii, 14; in atmospheric dust, i, 60-1; in soils, viii, 339-40; in waters, 40-1 Organicists, school of, x, 86 Organisms, binomial nomenclature, x, 84; cell constitution, 119, xv, 16, xvi, 142; chemical basis of, xii, 10-13; chemistry of, viii, 204-5, 348-72; chemosynthetic, xii, 15; earliest, xiii, 299, 303; frames and shells, xvi, 145; growth and forms due to physical laws, xvi, 142, 144-5; growth compared with crystallization, iii, 311; metals congenial to, viii, 148; microscopic (see Germs); reproduction of, x, 228; symmetry in, xvi, 155; variations, meristic and substantive, xvi, 155; vestiges in oldest rocks, iii, 249-50 (see Animals, Plants) Organogens, viii, 18 Organs (physical), disordered functions of, x, 318-65; vital function testing, 376-9, 382-3 Organs (musical), iv, 228-31; flue and reed styles, 234-5; intervals on, 208; temperature effects on, 231-2; pipes of, xv, 316 Oribasius, x, 31 Oriental Gobies, fins of, xii, 134 Orientation, in ancient temples, ii, 25-6 Orinoco Basin, arrau turtle of, xii, 193-4; chocolate in, xiii, 234; jaguars of, xii, 362 Orinoco River, caribes of, xii, 160; connections with Amazon, xiv, 187 Orioles, xii, 269 Orion, great nebula in, ii, 357, 359, 363, 364; moving clusters of, 343; distortions from sun's motion, 306 Orion Stars, ii, 117; moving clusters among, 343; radial velocities, 308 Orkney Islands, wave action at Wick, xiv, 300 Ornaments, bodily, xv, 253-4 Ornithorhynchus, xii, 272 Orongo, Mongolian, xii, 327 Orpathology, x, 318 Orräus, of Russia, x, 164 Orris Root, source, xiii, 189 Orthoclase, iii, 328; hardness of, 320 Orthodontia Appliances, xi, 373 Orthoptera, xii, 107-10 Osborn, Henry Fairfield, quoted, xii, 13 Osborn, Prof., on cave pictures, xv, 115-16; on Neanderthal Man, 97 Osborne, J. W., i, 319 Oscillation Circuits, vii, 263, 265, 373-4; theory of, 286-98 Oscillation Generators, vii, 273-8, 290-1 Oscillations, electric, iv, 313, 314, vii, 373-4; damped and undamped (see Damped, Undamped Waves) Oscillations, in planetary system, ii, 75 Osler, Sir William, x, 150-2; on conceptions of disease and therapy, 380; on Pasteur, 144; on sleeping sickness, 169; on yellow fever germ, 162-3; on hardened arteries, x, 335 Osler's Disease, x, 152 Osler's Spots, x, 152 Osmium, viii, 172; symbol and atomic weight, 383; valence, 178, 180 Osmosis, xiii, 91-2, 93-4 Osmotic Pressure, viii, 113, xiii, 93-4; bursting of fern spores by, 156; discovery and law, xvi, 164; in solutions, viii, 123, 311; water supplied to plants by, xiii, 102 Ostracoderms, iii, 260, 281-2 Ostracods, xii, 18-19 Ostriches, xii, 249; hunting of, by bushmen, xv, 134-5, 222 Ostrich Fern, xiii, 159 Ostrich Plumes, xii, 244 Ostwald, chemical work, xvi, 164, 165 Ostwald's Imperative, xi, 257 Oswego Tea Plant, xiii, 201, 205 Ottoman Turks, conquests of, xiv, 308-9 Otters, xii, 347 Ouachita Range, xiv, 227 Oughtred, William, xvi, 104 Ounce (leopard), xii, 357 Outcrop, defined, iii, 381 Outdoor Treatment, x, 240-1 Outgoing Reactions, xi, 54-6, 146 Outriggers, xv, 263-4 Outwash Plains, iii, 68-9 Ouzels, xii, 268 Ovaries, of plants, xiii, 46, 54-5, 118; beginnings, 317-18; grouping of plants by, 173-5; superior and inferior, 202-3 Ovariotomy, x, 122, 147 Over-Compound Generators, vi, 189-90 Overeating, auto-intoxication by, xi, 370; hardened arteries from, x, 335 Overhead Transmission, vii, 10-11, 14-24, 25 (see also Trolley System); in telephony, 104, 105 Overheated Liquids, viii, 304 Overshot Wheels, v, 76 Overtones, iv, 213; of organs, 230-1; quality of sounds due to, 233 Overwork, fatigue from, xi, 269, 272, 371; muscular soreness from, ix, 81 Ovules, plant, xiii, 118, 119; action of fertilized, 153; naked and enclosed, 173-5 Owen, morphology studies, xvi, 140-1 Owens Automobile, vi, 104 Owen's Valley, California, earthquake of, xiv, 334, 335 Owls, xii, 267 Oxalic Acid, viii, 222, 336 Oxbow Streams and Lakes, iii, 34, xiv, 162 Oxford University, foundation, xvi, 100 Oxidation, defined, viii, 380; in water, 35; of organic substances, 266; of sewage, 326, 327; of iron, v, 316 (see Rusting); power extraction by, ix, 16, 24 Oxide of Manganese, ancient use of, xv, 113 Oxides, defined, viii, 380; chemical formation, 11-13, 20, 36; combinations with water, 38-9; extraction of metals from, 47, 131, 271; metallic and nonmetallic, 20; ores, 47, 198 Oxyacetylene Blowpipe, i, 33 Oxy-acids, viii, 98, 380 Oxyhemoglobin, ix, 259-60 Oxygen, viii, 17, 34-6; affinities, i, 12, viii, 33, 36, 47, 77, 85, 87, 134, 155; amount inspired in sleep, xi, 283, 285; atmospheric, i, 10, 11, 24, 25; atmospheric, viii, 67; atomic weight, 33, 39, 383; atomic weight base, 92; body needs and supply, ix, 198-9, 253-62, 267-8, x, 338-9; boiling and freezing points, iv, 173; carriers of, viii, 71; carrying of, in blood, ix, 182-3, 258-61, x, 338-9; combustion and, i, 10, iv, 138, viii, 12-13, 53, 54, 55-6, 61; consumption by gas lighting, vi, 264; consumption of, in exercise, ix, 261-2; corrosion of metals by, viii, 13; critical temperature, i, 29, iv, 174; deficiency effects, i, 322, 328, ix, 268, x, 238, xi, 371; density of, iv, 110; diffusibility, viii, 108; discovery, 34, 170, xiv, 65, xvi, 120; energy source, viii, 268; elimination from body, 353; explosion with hydrogen, viii, 62; hydrocarbon derivatives, 52, 212, 216-20; importance, i, 24, 25; in chlorophyll, xiii, 80; in coal series, iii, 345; in earth's crust, 308, viii, 19, 129, 192; in organic compounds, 64, 204; in proteins, 351; in steel making, vii, 321; in water, viii, 39-40, x, 26; industrial uses, i, 32-3, viii, 274; liquefied, i, 29, iv, 171, viii, 68; melting point, iv, 162; molecular structure, viii, 26-7, 36; molecular velocity in, iv, 133, viii, 24; most active form, 36, 41; negativeness of, 31; necessity of, to life, ix, 16, 18, 22, 267-8; plant uses of, viii, 336-7, 340-1, xiii, 14, 80, 81, 109, xiv, 64-5; potential energy in, iv, 82; preparation, viii, 34-5; production by plants, 49, 335, xiii, 81, 82, 109, xiv, 65; production from liquid air, i, 30, 32-3, viii, 68, 274; production from nitric acid and nitrates, 72; production from water, 30, 31, 274; rock decomposition by, 194, iii, 24, 25; rusting produced by, 25; solubility in water, viii, 35, 40, 111; supply of, in air, ix, 254, 267-8; symbol, viii, 383; valences to, 178, 179-80 Oxygen Compounds, viii, 20, 34, 36-41, 70-4 Oxygen Cycle, viii, 334, 350 Oysters, iii, 260, 272, xii, 58-63; enemies and destroyers, 50, 70, 72, 73; food procuring by, ix, 19, 74; raw, digestion of, 233 Oyster-Shells, deposits of, iii, 272 Ozone, i, 15-16, 378, vii, 353-5; activity of, viii, 36; allotropic form of oxygen, 43; electrical production, vii, 238-9, 301; molecular structure, viii, 26, 36; production by lightning, i, 153 Pacas, xii, 289 Pacific Coast, geological changes, iii, 213, 222, 214 (maps); ports and commerce of, xiv, 269; potash from seaweeds, viii, 279; seaweed of, xiii, 27, xiv, 67, 68; shellfish of, xii, 62, 65, 68, 74; thunderstorms rare, vii, 218; width of continental shelf, xiv, 285 Pacific Coastal Plain, xiv, 215 Pacific Coast Forest, xiv, 374 Pacific Drainage System, xiv, 189-90 Pacific Islands, xiv, 277; coco palm of, xv, 125; weapons of, xv, 216, 219 Pacific Ocean, climate on opposite coasts, xiv, 345; coral reefs in, 264; currents of, 304, 305; depths, iii, 51, xiv, 23; extent, 22; herring of, xii, 156; salmon of, 157; seals of, 333-4; sharks of, 145, 146; shoal-water belt, xiv, 25; temperatures, 297; trade winds, i, 127; unchanged for ages, iii, 55; volcanic dust in, 55; whales of, xii, 298 Pacific Type of Coasts, xiv, 247-9, 250 Pack Rats, acquisitiveness of, xii, 292-3 Packing, Maudsley's cup leather, v, 99, 376 Paddle-fish, xii, 151 Paget, Sir James, xvi, 184 Pain, xi, 116-21; "arrival platform" for, ix, 146; contact sense of, 91; expression of, by dogs and monkeys, xv, 64-5; no space perception by, xi, 164; organs and nerves in skin, ix, 314; purpose as warning, 87; sense of, in infants, 349; use of morphine in, x, 381 Painter Fogs, i, 96-7, 378 Painting, art of, beginnings and development, xv, 108-9, 110-16, 120-1, 297-303, 325; by compressed air, i, 29, iv, 130, v, 136; of body, xv, 255-6 Paintings, depth impressions in, ix, 120; skies in, i, 105 Paints, ancient, xv, 113-14; chemistry of, viii, 264-6; colors of, iv, 369-70; drying oils in, viii, 245, 247; lead in, 162; linseed oil in, 231 Pajero, xii, 364 Paleolithic Man, iii, 303-5; horses of, xii, 307; implements of, xv, 103, 105-9; state of, xiii, 209-10 Paleontology, defined, iii, 381; history, xvi, 169, 170, 172 Paleophytology, xvi, 167 Paleozoic Era, iii, 20, 381; animals, 263, 266-75, 276-8, 284, 285, xii, 49, 75, 104, 142, 151, 165; climatic zones in, iii, 173; divisions and species of, xv, 71; plants, iii, 251-5; rocks and history, 179-207; vertebrates absent, 261 Paleozoic Rocks, iii, 179-207; recognizable by fossils, 174, 179; why rich in fossils, 264 Palestine, ancient rain measurements, i, 68, 213; climate changes in, xiv, 361-2, 379; maritime plain of, xv, 138 Palisades of the Hudson, iii, 111, 212, xiv, 108-9, 122; blocks at foot of, 76; jointing at Bergen Cut, 133 Palladium, viii, 173; as catalyzer, 103; symbol and atomic weight, 383 Pallas, meteor found by, ii, 284 Pallas (asteroid), discovery, ii, 255; orbit, 258 Pallor, causes of, x, 337; temporary, ix, 161, 162, 163, 165, 166 Palm Beach, millionaires at, xi, 52 Palmer, Dr. G. T., i, 323 Palm Family, xiii, 188 Palmitic Acid, viii, 220, 221, 350 Palm Kloof, xiv, 369-70 Palm Oil, African development and, xiii, 11; source, xiv, 383; vegetable fat, viii, 246 Palm-Oil Tree, xiii, 188 Palms, cocoanut, xiii, 219-20; first appearance, xiii, 319; in tropics, distribution of, xiv, 368; leaves of, xiii, 176; monocotyledons, 178; trunks of, 26 Paloverde, leaves of, xiii, 379 Pamias, rock disintegration on, xiv, 73-4 Pamlico Sound, bar of, xiv, 264 Pampas, absence of trees in, xiv, 381; armadillo burrows on, xii, 284; cattle-raising and agriculture on, xiv, 384; dust whirls, i, 60; flatness of, xiv, 158, 216; grass and other plants of, xiii, 375-6; grasses, drying of, xiv, 381; horses of, xii, 307; true plains, xiv, 218 Pampas-Cat, xii, 364 Panacea, x, 16 Panaceas, medicinal, x, 41 Panama Canal, Caribbean traffic, i, 282; Chagres River and, xiv, 195; dredges used, v, 255-6; material excavated, 258 Panama Canal Zone, health conditions, i, 327, x, 162; sanitary control, costs, xiv, 344, 356; temperatures, i, 209 Panama, Isthmus of, anteaters of, xii, 283; earthquakes on, xiv, 331; pearl fisheries of, xii, 62; sea devils of, 150; temperature, i, 208-9; yellow fever extermination, x, 162, xiv, 356, 357 Pancreas, functions of, ix, 237, x, 330, 347; secretin effects on, 325 Pancreatic Juice, viii, 358, ix, 237-8, 242, x, 325-6, 330; of infants, ix, 346 Pangolins, xii, 281 Pangong Lake, Tibet, xiv, 211 Panpipes, xv, 315 (fig.), 316 Panspermia, xii, 9 Panthers, xii, 363; stalking of game, xi, 224 Pantograph, in trolley systems, vii, 197 Papaw, origin, xiii, 226 Paper, electrical conductivity, iv, 259; electrification by tearing of, 260; heat conductivity, 179; making of, v, 289-99, 380; making of, in ancient Egypt, xvi, 72; made from corn fiber, xiii, 213; made from mulberry, v, 290, xiii, 244; made from spruce wood, 10, 236; Manila, 240; origin of name, xv, 157 Paper Machines, v, 295-9, 377 Paper, Mulberry, xiii, 244; bark as cloth, xv, 256-7 Paper Pulp, making of, viii, 153 "Paper Sailor," xii, 78 Paper Showers, i, 359 Papier-Maché, ancient, xvi, 73 Papillæ, xi, 70-1 Papin's Digester, iv, 170-1 Papuans, hair of, xv, 38; prayer, 346 Pappus, Greek author, xvi, 94-5 Papyrus, v, 289; Egyptian, xvi, 72 Paracelsus, x, 46-50; classifying tendency of, 83; compared with Vesalius, 53; followed by Van Helmont, 68; Locke on, 75 Parachutes, v, 234 "Paradise Lost", quotations, ii, 36, 210-11, 350 Paraffin, viii, 51, 208; combustion of, 52; meaning of name, 206, 380; melting requirements, iv, 162 Paraffin Candles, viii, 247 Paraffins, Paraffin Hydrocarbons, viii, 206-210, 241; contrasted with benzenes, 232-4; defined, 380; derivatives, 210-32; molecule configuration, 233; residues in benzenes, 235-6, 238-40; unsaturated, 230-2 Paragreles, i, 341, 378 Parallactic Motion, ii, 317 Parallax, ii, 311-18; Galileo's method, 55; Hipparchus on, 32; in distance perception, xi, 182; photographic study, ii, 137, 314 Parallel Forces, resultant of, iv, 99 Parallel-veined Leaves, xiii, 32, 37 (fig.), 176, 177, 178 Parallelogram of Forces, v, 184-6 Paralysis, electric treatment, vi, 17, vii, 238 Paranthelion, i, 378 Parantiselenæ, i, 378 Para Rubber, xiii, 246-7 Paraselanæ, i, 180, 183, 378 Parasitic Clouds, i, 104, 378 Parasitic Plants, xiii, 15, 21, 100, 364 Parasitology, xvi, 181 Parchment Paper, strength, viii, 255 Paré, Ambroise, x, 46, 54-6, 97, 129, xvi, 108 Pareira, "Materia Medica", xvi, 186 Parental Instinct, xi, 56 Parental Solicitude, xi, 149 Parents, care of children, ix, 352; children's resemblance to (see Heredity); pleasure of, in children, 153 Parhelia, Parhelic Circles, i, 179-80, 181, 183, 378 Parian Chronicle, meteor recorded in, ii, 284 Paris, balloons in siege of 1871, v, 225; bombardment in World War, 369-70, iv, 201-2; Salpêtrière Hospital, xvi, 184; sewage disposal, viii, 327 Paris Green, viii, 169 Paris-London Air Service, i, 44-5, 95, 285-6 Paris Observatory, ii, 58 Paris, University of, founded, xvi, 100; medical school, x, 38 Park, Mungo, xvi, 123 Park Cattle, xii, 331 Parker, morphology studies, xvi, 140-1 Park Forests, xiv, 374 Parkinson, James, x, 112 Parklike Landscapes, xiii, 374-5, 376 Parliament, British, gold mace of, xv, 208 Parmenides, Greek philosopher, xvi, 84 Paros, fossils in rocks of, iii, 14 Parrakeet, Carolina, xii, 266 Parrots, xii, 265, 266-7; dyeing of, 179; monogamous, xv, 276 Parsec, astronomical unit, ii, 315 Parsley, xiii, 200-1, 223 Parsnips family, xiii, 200-1; origin, 223; swelled roots, 19 Parsons Steam Turbine, v, 150-1, 382 Particles, technical meaning, iv, 382 Partridge Berry, crossbreeding devices, xiii, 122; in madder family, 205; illustration, 96 Partridges, xii, 261 Pascal, Blaise, atmospheric pressure studies, iv, 114-16; mathematical work, xvi, 105, 114, 119; vacuum studies, 110 Passenger Aircraft, i, 41-3, 44-5, 50 Passerine Birds, xii, 268-9 Passiflora, origin, xiii, 226 Passion Flower, tendrils, xiii, 112 Passions (see Emotions) Past comparisons with present, vii, 76 Pasteboard, making of, v, 299 Pasteur, Louis, x, 136-44, 208; bacteria studies, xvi, 143, 182, 184, 185; chemical work, 163-4; courage of, x, 101; Lister and, 144, 145, 146; references to work of, 107, 132, 133 Pasteurization, x, 139-40 Pasteurized Milk, xiii, 71, x, 132, 140; scurvy from, 266; vitamines in, 263, ix, 347 Pastries, as food, x, 273, 315 Patagonia, bushlands of, xiv, 381; huanacos of, xii, 313; plains of, xiv, 218; rhea of, xii, 249; tides of, xiv, 298 Patagonians, height of, xv, 39 Patches of Peyer, x, 287-8 Patella, ix, 69, 70 (fig.) Patent Medicines, remarks on, vii, 241 Pater Noster, in Aztec, xv, 169 Pathfinders, of flowers, xiii, 134, 140 Pathogenic Germs, x, 194-5 (see Disease Germs) Pathological Anatomy, Morgani's work in, x, 98 Pathology, Cellular, founded by Virchow, x, 119, 128 Patriotism, sentiment of, xi, 145, 151 Pavloff, Ivan, x, 131, 319 Pavlov's Law, xi, 198, 201 Pay-as-you-enter Cars, vii, 184 Peach Trees, xiii, 197, 226 Pea Family, xiii, 198-9; antiquity, 324-5; fertilization, 137-9; food devices, 97-8; nitrogen-fixing parasites, i, 35, xiv, 66; seed dispersal by, xiii, 339, 347 Peake Deep, xiv, 289 Peanuts, oil of, ix, 28 Pearl Islands, xii, 62 Pearls, finding by X-rays, vii, 256; origin, xii, 62-3, 66 Pearly Nautilus, xii, 75-6; evolution of, iii, 273-5 Pear Psylla, honeydew of, i, 351-2 Pearson, eugenic studies, xvi, 157; on artificial selection, 154; statistical methods, 153 Pear Trees, development of fruit, xiii, 54; in rose family, 197; origin, 224, 226 Peary, Arctic soundings of, xiv, 22; mirage of Crocker Land, i, 173 Peas, as food, viii, 365, ix, 34, x, 262; crossing experiments, 231-2; flowers, xii, 44 (fig.); food-obtaining devices, 97; leaf-tendrils, 38; leaves, 36-7, 113; origin, 223; petals, 47, 190; pods, dry fruit, 54; seeds, 56; sleeping of leaves, 88-9 (see also Pea Family) Peat, elements, iii, 345; formation, xiii, 68, 313; in relation to coal, iii, 344; in sheep plant, xiii, 380; per cent of carbon in, viii, 44; wood fiber seen in, 45 Peat Bogs, dust from burning, i, 56, 57; extent of present, v, 173; of Denmark, xv, 87 Pebrine, Pasteur's study of, x, 140 Peccaries, xii, 310-11; jaguars and, 362 Pekans, xii, 350, 351 Peking, Temple of Sun, ii, 26 Pelagic Fauna, xii, 16 Pelee, Mount, eruption, iii, 102-3, xiv, 28, 325; dust from eruption, i, 58, 59; earthquakes preceding eruption, xiv, 338 Pelée's Hair, iii, 105 Pelicans, xii, 254 Pellagra, x, 265, 268; cause of, viii, 351; eruptions on uncovered surfaces, x, 254 Pelterie, R. Esnault, v, 175-6 Pelton Wheels, v, 77-9, 80, 81, 170, vi, 368 Pelvis, ix, 63, 66-7 (fig.); in man and apes, xv, 58; vestiges of, in snakes, xii, 213 Pelycpoda, xii, 58-63 Pemba, clove production, xiii, 263 Penang, clove trees, xiii, 262 Penck, Prof., climate studies, xiv, 361; land and water curves, 26 Pendulum, discovery, v, 63-5; Galileo's observations, ii, 53; gravity action on, iv, 97-8; oscillations and regulation of, 147, 225, 226; types in clocks, v, 73, 74 Pendulum Clocks, invention, ii, 58; escapement, v, 73-4; regulation to temperature, iv, 147 Peneplains, iii, 30, 34-5, 381; cretaceous, 232 Penetrating Radiation, i, 143-4, 146, 379 Pennsylvania, coal beds, iii, 199, 347-8; former volcanoes, xiv, 318; glacial soil of, 70, 170; natural gas, iii, 355 Pennsylvanian Period, iii, 198-202; coal deposits, 198-201, 345; insects, 279; plants, 252-4 Pennyroyal, source, xiii, 205 Penguins, xii, 251 Penstocks, vi, 363 Pentane, derivatives, viii, 210 Pentose, viii, 229 Pentstemon, corolla, xiii, 201 Penumbra, of shadows, iv, 332-3 Peony, pollen of, xiii, 124 Pepin, Lake, xiv, 202 Pepo, xiii, 54 Pepper, black, xiii, 265; red, 223 Peppermint, viii, 251, 252 Pepsin, in gastric juice, ix, 235, x, 320, 326 Peptones, x, 277 Pepys, Samuel, "Diary" quoted, iv, 53 Per, defined, viii, 380 Perceptions, defined, xi, 160-2; differences in power of, 152; Greek theories, xvi, 87; misinterpreted, x, 358; of color, ix, 114-17; of light and shade, 105; of objects, 105-11; of space, xi, 162-91; of time, 192-6; relativity of, xvi, 85 Percussion, in diagnosis, x, 99, 110, 371 Percussion Cap, viii, 145 Percussion Drills, v, 129, 261-2, 263 Percussion Shells, v, 372 Percussive System, of oil boring, v, 265-7 Perennials, buds, xiii, 53; roots, 16; planting tables, 289-96 Perfection, Man's struggle for, xv, 38-9 Perfumes, chemistry of, viii, 251-2 Pericles, reference to, x, 20 Peridot, iii, 334 Perier, Pascal and, iv, 114-15 Perigee, defined, ii, 197 Perigord District, human relics, iii, 304-5 Perihelion, defined, ii, 50, 275 Period, technical meaning, iv, 383 Periodic Breathing, x, 340 Periodic Classification, viii, 177-83, 307, 309 Periods, Geological, iii, 19-21, 381 Peripatus, xii, 81 Perique Tobacco, xiii, 258 Periscopes, v, 200-1 Peristalsis, x, 327 Peritonitis, asepsis in, x, 147; causes of, 195, 288 Periwinkles, xii, 71 Perkins Ice Machine, v, 358, 379 Perlite, viii, 160, 274 Permanent Magnets, iv, 243, vi, 30, 37, 117, vii, 372; care of, vi, 34, 38; lifting force of, iv, 289 Permian Period, iii, 20, 202-5, 381 Perpetual Motion, v, 97, vi, 214, xvi, 135 Perpetual Snow Line, iii, 59 Perpetuation of the Race, ix, 324-44; marriage and the family, xv, 273 Perret, Prof. F. A., i, 194 Perrine, astronomer, ii, 136, 146, 262, 362 Perseids, ii, 288 Perseus, star clusters in, ii, 336, 343 Persia, ancient, Mediterranean aims, xiv, 306; astronomy of ancient, ii, 26; cheeta of, xii, 365; climate changes, xiv, 361-2; lions of, xii, 359; magi of, xvi, 59; plateau of, xiv, 222; sun-worship, ii, 20; use of opium, xiii, 253; wild asses of, xii, 308 Persian Cats, xii, 356 Persian Gulf, first civilization around, xvi, 47; pearl fisheries of, xii, 62 Persian Language, xv, 162; words from, in English, 161 Persimmons, xiii, 226, 352-3 Persistence of Vision, iv, 346-7, v, 329, vi, 155 Persistency and will, xi, 264 Personal Equation, xi, 156 Personal Hygiene, disease prevention through, x, 302-17; teaching of, 283-5 Personality, changed in emotion, xi, 134; dreams as revelation of, 302; loss of, in crowds, 324, 325-6, 329-30; source, 33; splitting of, in hysteria, x, 360-1, 362 Perspective, xi, 181-2; in distance perception, ix, 119-20 Perspiration, absorption by various materials, x, 307, 308, 309; amount of "insensible," 70-1; caused by fear, xi, 131,132, 133; constitution of, x, 310; humidity and, i, 77; temperature regulation by, 317, v, 348-9, ix, 169, x, 251, 274 (see also Sweat, Cold Sweat) Peru, ancient use of cocaine, xiii, 254; ancient corn-growing, 212; ancient stone structures of, xv, 271; conquest of, xiv, 250; foot plow of Indians, xv, 236 (fig.); harbors and commerce, xiv, 265, 266; Incas (See Incas); rainfall and fog, i, 95, 96-7; rain-tree, 352; source of quinine, xiii, 251; words derived from, xv, 161 Peruvian Art, ancient, xv, 297 (fig.), 311 (fig.) Peruvian Bark, xiii, 250-1 Peruvian Earthquake, xiv; tidal waves of, xiv, 337 Peruvian Paint, i, 96-7, 378 Pessimism, physical causes, xi, 339, 369-70, 372 Pestles, xv, 238-9 Petals, of flowers, xiii, 45, 47; importance in classification, 47; first appearance, 318; lacking in some flowers, 46 Peter Pan, story of, xv, 330 Peters, Dr., of Hamilton, ii, 256 Petiole, of leaves, xiii, 34, 35 Petit, Jean-Louis, x, 90-1, xvi, 161 Petrels, xii, 251, 252 Petrified Animals and Plants, iii, 15-16, 126-7 Petroleum, composition, products, and supply, viii, 208-10; fluorescence of, iv, 323, 379-80; origin and occurrence, iii, 348-54; production and supply (U. S.), v, 172-3; supply and approaching exhaustion, vii, 309 Petrology, iii, 381, xvi, 170 Pfeiffer, immunity theory of, x, 211; influenza germ discovery, 295 Phaestos Disk, xv, 176 (fig.) Phagocytosis, x, 209-10 Phaleropes, xii, 262 Phanerogams, xiii, 62-3; reproduction, 117-54 (see Flowering Plants) Phantasies, in psychoanalysis, x, 365 Phantom Circuits, vii, 105-6, 119 "Pharaoh's Chicken," xii, 260 Pharmacognosy, xiii, 249 Pharmacology, x, 381, xvi, 186; chemical, founded by Paracelsus, x, 50 Pharmacy, history, xvi, 186-7 Pharnyx, condition in thirst, xi, 66 Phase (electricity), defined, vi, 204-5; "in," 168; "out of," 167, 204 (see also Single-Phase, Two-phase, Three-phase) Phase Law (chemistry), xvi, 136, 164 Phase Relations, vi, 167-9, 171-4 Phases, of Mars, ii, 227; of moon, 190, 193-5, 196 Phasing-in, defined, vi, 263, 342 Pheasants, xii, 261; hearing of, i, 188 Phenology, i, 254-6, 379 Phenolphthalein, viii, 294, x, 378 Phenols, viii, 236, 237-8, 380; as disinfectants, 333 Philadelphia, summer of 1816, i, 360; water supply of, xiv, 140; yellow fever epidemic, x, 159 "Philadelphia Ledger," first Hoe press, v, 301 Philippine Islands, aerial exploration work, i, 47; baguios, 136; beriberi in, ix, 35, x, 257; carabao of, xii, 329; civilization in mountain valleys, xv, 131; continental islands, xiv, 274; copra production, xiii, 220; dipterocarp forests, 350; fiber-wear, 236; fire obtained by friction, viii, 89; fire by air-compression, v, 128; Manila hemp, xiii, 239-40; new volcano in Camiguin, xiv, 320; ocean depths near, iii, 51; octopod fishing, xii, 78; rainfall at Baguio, i, 110; rice growing, xiii, 213, 214; Weather Bureau, i, 223 Philo of Byzantium, thermoscope, i, 69 Philosophers, Faraday on, x, 376 Philosopher's Stone, xvi, 14 Philosophy, Greek, xvi, 76-80, 83-8, 99; 18th century, 117; mediæval, x, 35; recent, xvi, 195-8; Roman and Mediæval, 99-100; science and, 112, 115; social spirit and, 195 Philostratus, on death of Domitian, ii, 221; on sun, 165 Phlegmatic Temperament, xi, 153 Phlegraean Fields, xiv, 225, 316, 320 Phlogopite, iii, 334 Phœnician Language, xv, 162 Phœnicians, Africa circumnavigated by, xiv, 196; commerce of, 307; in Iberian group, xvi, 49; introduction of cats by, xii, 355; invention of Alphabet, xv, 175; navigation of, v, 182; ships of, xiv, 265 Phonisms, xi, 222 Phonograph v, 328-9, 381; combined with motion pictures, 331; making of records of, iv, 240; motor-driven, vii, 87; vibration rates in, ix, 101 Phosgene, viii, 263, x, 187 Phosphate Baking Powders, viii, 136 Phosphate Group, viii, 93 Phosphate of Lime, plant needs of, xiv, 67 Phosphate Rock, as fertilizer, viii, 89, 344, 345; occurrence and supply, xiv, 67 Phosphates, derivation and uses, viii, 89; fertilizers, 153, 279-80; in blood, x, 280; in urine, x, 343; test, viii, 290 (see also Calcium Phosphate, Sodium Phosphate) Phosphine, viii, 89 Phospholipins, viii, 351 Phosphorescence, iv, 380; of decaying wood, i, 346; of marine animals, xii, 18-20, 24, 84 Phosphoric Acid, composition, viii, 89, 115; in body, x, 280; plant needs and sources, xiv, 67, 68, 69; salts from, viii, 116; solubility, 112; stability, 115 Phosphorus, viii, 18-19, 87-9; burning under water, 54-5; ignition point, 53; in body, functions, 354-5; in fertilizers, 343, 344-5; in iron ores, iii, 356; melting requirements, iv, 162; plant needs of, viii, 337, 341, 342, 344-5, ix, 29; sources, viii, 345; symbol and atomic weight, 383 Phosphorous (plant), ancient name of Venus, ii, 191 Phosphorus Pentoxide, viii, 87, 89 Photisms, xi, 222 Photochemical Climate, i, 325, 379 Photo-engraving, xvi, 129 Photographic Action, of different colors, iv, 365-6 Photographic Films, composition, viii, 255; invention, v, 330-1 Photographic Map-Making, i, 45-8 Photographs, savage ideas of, xv, 331; X-ray, vii, 250, 253-4 Photography, chemistry of, viii, 171-3; color, iv, 368-9; history, xvi, 192; in astronomy (see Astronomical Photography); in aurora studies, i, 162; in lightning study, 146-8; lenses used in, iv, 373; underwater, i, 47-8 (see also Camera) Photometers, vii, 374 Photosphere, defined, ii, 173 Photosynthesis, xiii, 81, 105, 109; in cactus plants, 378 Phrenic Nerve, xi, 37 Phrenology, ix, 145 Phrygian Stone, ii, 284 Phylum, Phyla, xii, 29 Physas, xii, 69, 71 Physical Changes, contrasted with chemical, viii, 14-15 Physical Characters, classification of man by, xv, 36-47 Physical Chemistry, viii, 296-316 Physical Examinations, x, 370-1 Physical States of Matter, viii, 22, 382; changed by heat, iv, 139, 151-3; chemical interpretation, viii, 296-316; in relation to pressure and temperature, 303-5; suspended changes, 113, 304, 305 Physical Training Exercises, x, 305 Physicians, Babylonian laws controlling, x, 14-15; capacity and preparation of, 367, 369; earliest distinction from surgeons, 16-17; essential duties of, 21, 75-6; Oath of Hippocrates, 18-19; Paracelsus on province of, 49 PHYSICS, Volume iv Physics, branches of, iv, 50; concrete science, xvi, 42; daily applications of, iv, 10, 187, xvi, 17, 19, 30; defined, 36; energy the subject of, iv, 12, 13-14, 50; exact, positive science, x, 368; history of development of, iv, 11, 18-20, 24-30, xvi, 54, 82, 89, 91-2, 101, 103, 105, 109-10, 129-38; interrelation of phenomena of, iv, 39, 40; measurements in, iv, 45, xvi, 129-30; medicine and, x, 81, 369; realm of, iv, 13-20; technical terms, glossary, 381-4 Physik, Philip, x, 121 PHYSIOGRAPHY, Volume xiv Physiography, defined, iii, 381, xvi, 36 Physiological Meteorology, i, 316-31 PHYSIOLOGY, Volume ix Physiology, daily applications, xvi, 15, 16-17; history of development, x, 29, 30-1, 81, 125-8, xvi, 82-3, 180; medicine based on (Boerhaave), x, 76-7; science of body, xvi, 37; teaching of, remarks on, x, 284-5 Piano, automatic, vi, 97; evolution of, xv, 318; intervals on, iv, 208; sympathetic vibration, vii, 261-2; vibration rate of notes, ix, 99 Picard, astronomer, ii, 58, 59, 64 Piche, A., deperditometer, i, 319 Pickerel Frogs, xii, 180 Pickerels, xii, 163 Pickering, Prof. Edward C., astronomical work, ii, 17, 116, 118, 122, 127, 130, 132-3, 133, 145, 146, 233, 237-8, 297, 307, 359 Pickering, W. H., ii, 271 Picric Acid, viii, 63, 238, 262 Pictou, Nova Scotia, pollen shower, i, 359 Picture Writing, xv, 167-9 (see also Hieroglyphics) Pictures, depth impressions in, ix, 120 Piddington, Henry, i, 135 Piddocks, xii, 59 Pie Crust, "taste" of, xi, 127 Piedmont Glaciers, iii, 60 Piedmont Plateau, xiv, 27-8, 213; building stones of, iii, 371, 372; forests of, xiv, 378; geology, iii, 28, 112, 172, 188, 231-2 Pig Iron, v, 318, viii, 157, 158, 159; electric furnace production, vii, 312 Pigeons, xii, 265; equilibrium disturbances in, x, 126, xi, 31 Pigments, viii, 162, 264, 265-6; ancient, xv, 113-14; colors of, iv, 369-70 Pigs (swine), xii, 310-11; evolution of hoof, iii, 300 Pikas, xii, 287-8 Pikes (fish), xii, 163 Pike's Peak, shadow in sky, i, 170 Pile-driving, by water jets, v, 88-9 Pileus, of mushrooms, xiii, 163 Pilgrim Shell, xii, 65 Pili Erectores, xi, 113 Pillows, and sleep, xi, 290 Pillsbury, Prof., quoted, xi, 168-9 Pilot Balloons, i, 21-2, 312, 379 Pilot Charts, i, 273-5 Piloting, wireless system, vii, 285 Pilot Lights, vi, 276 Pilot Snakes, xii, 219-20, 233 Piltdown Man, xv, 92-5; brain of, 96; implements of, 107; period of, 102 Pimento, origin, xiii, 265 Pimpernel, xiii, 203 Pimples, ix, 186, 187; germs of, x, 201 Pineapple, American origin, xiii, 221, 226, xiv, 382; fiber of leaves, xiii, 236; introduction, 10; water-holding leaves, 106 Pineapple Family, in tropical forests, xiii, 362-3; restricted to America, 320 Pine Forests, conditions favorable to, xiii, 371; pollen showers, i, 359 Pinel, Philippe, x, 110-11 Pine Needles, measuring heat in, vi, 62-3 Pine Trees, in American forests, xiv, 372, 374; lightning dangers, i, 155; planting conditions, xiii, 270; pollen of, 118, 149; polycotyledons, 60; seeds of, 345; seed-dispersal, 343; wind-fertilization, 148 (see also Conifers) Pinhole Camera, ix, 107-8, 109 Pinion Gears, v, 29, 30 (fig.) Pink Family, petals and sepals, xiii, 194, 195 Pink Lady's Slipper, xiii, 145 (fig.) Pinks, meadow, xiii, 133-5; sea or marsh, 204 Pinuela, origin, xiii, 226 Pipal Tree of India, xiii, 108 Pipefishes, xii, 163 Pipe Organ, of Ctesibius, v, 110-11 (see Organs) Pipes, lead, viii, 162 (see also Water Pipes) "Pipes", in ingots, v, 323 Pipes of Pan, xv, 316, 315 (fig.) Pipette, viii, 294, 295 (fig.) Pipe Vine, fertilization, xiii, 131-3 Piracy, Stream, iii, 38-9, xiv, 177-83 Piranha, xii, 159 Pirogoff, Nikolai, x, 131 Pisa Cathedral, lamp in, ii, 53, v, 63-4 Pisa, Leaning Tower (see Leaning Tower) Pistillate Flowers, xiii, 46-7 Pistils, xiii, 45, 46; in reproduction, 117-22; of highly cultivated plants, 51 Pistons, measurement of work of, vi, 81-2; reciprocating and rotating, v, 148; service in internal combustion engines, i, 57-9 Pita, origin and product, xiii, 244 Pitch of Sounds, iv, 205-6, ix, 99-100, xi, 104, 105; extremes of audibility, iv, 204; hearing of, xi, 103; modulations of, in voice and music, iv, 209; motion effects on, iv, 209-10; of bells, 222; of organ pipes, 230-1, 231-2; of vibrating strings and rods, 223-4; resonators for special, iv, 232, 233; temperature effects on, 231-2 Pitchblende, radium from, xvi, 193 Pitcher Plant, xiii, 39-40 Pith Balls, electrification of, iv, 257-8, vi, 286-7 Pithecanthropus Erectus, iii, 302-3, xv, 88-92; brain of, 96; period of, 102 Pittsburg, dryness of, i, 337; growth as river city, xiv, 219; smoke nuisance, i, 64, 65; "Smoky City", vii, 343; water supplies of, viii, 318; water supply and typhoid rate, 322 Pittsburg Bituminous Coal Bed, iii, 200-1, 347 Pituitary Gland, x, 347 Plaaters Kill, xiv, 179 "Place in the Sun", struggle of plants for, xiii, 27-8, 38-9, 76-7, 361-3 Placental Animals, iii, 297, 298; evolution of, xii, 271, 332 Placer Deposits, defined, iii, 381; gold, 331, 365-6, 366-7; platinum, 335; tin, 369 Plagioclase, iii, 328-9 Plague, Greek ideas of, x, 285; immunity to, 207; inoculation against, 208; racial susceptibility to, xv, 50, 51 Plagues, great, x, 153-70; uncleanliness and, xv, 49 Plains, xiv, 212-19; civilization in relation to, xv, 128; define and distinguished, xiv, 27, 213, 220; Great (see Great Plains); outwash, iii, 68-9; perfect, seldom attained, 35; populations mostly on, xiv, 218-19; sea-cut, 46-7, 216; surfaces of high and low, 28 Planarians, xii, 44 Plane of Ecliptic, ii, 70, 163 Planers, invention, v, 47 Plane Tree, in landscaping, xiii, 271-2; leaf buds, 34 (see also Sycamores) Planet Deep, iii, 51 Planetary Motions, ii, 163, iii, 158, 159; compared with whirling of pail, iv, 71; Copernicus on, ii, 43-4; gravitation and, iv, 95, 98; Huygen's studies, ii, 58; irregularities, 66, 67, 71, 73, 79, 87; Kepler's laws, 49-52; Ptolemaic theory, 35-6; spectroscopic investigation, 120-1; theory of relativity and, 80-1; tidal friction theory, 376-7 Planetary Nebulæ, ii, 360; distribution and motion, 364; star streaming by, 347; stars and, 308-9 Planetary Orbits, ii, 162-3; deviations, 66, 67, 79; elliptical form, 39, 50-1, xvi, 102; first thought to be circular, ii, 34, 49; variations in elements, 74-5 Planetesimal Hypothesis, ii, 372-4, iii, 160-3; not sustained by Mt. Wilson studies, ii, 157; origin of moon by, 376; rings of Saturn by, 266 Planetesimals, ii, 374, iii, 161, 162 Planets, atmospheres of, i, 10, ii, 231-2, 245; conjunction recorded by Hindus, 21; days and seasons in, 228; distances and periods, 51-2; erratic amplitudes, 25; farthest, 267-9; hypotheses of origin, ii, 369-74, 379, iii, 160, 162; inner, ii, 189-92; law of sun's attraction, 65; life on, 245-50; lucid, 264; minor, 16, 254-9 (see Asteroids); motions (see Planetary Motions); orbits (see Planetary Orbits); photography in study, 130-4; sizes and motions, 162-3; of stars, 252-3; trans-Neptunian, 270-2; weighing of, 75-7 Plankton, Sea, xii, 17-21, xvi, 147-8; copepods in, xii, 84; one-celled animals of, 25 Planning, of work, xi, 377-8 Planosphere, xvi, 91 Plantain Eaters, xii, 265 Plantains, xiii, 217, 226 Plant Breeding, ix, 327, 337 Plant Classification, xiii, 168-81; by cotyledons, 60-1; by factor expressions, 330; by morphological characters, xvi, 165-6; by reproductive processes, 166-7; former method, xiii, 175; Linnæan System, x, 84; outline, iii, 251 Plant Distribution, xiii, 337-84; determined by climate, xiv, 364-79, 380-1; facilitated by land arrangement, xiv, 21; Ice Age and, xiii, 321, xiv, 375-7; importance of study of, xiii, 12; land changes and, xiii, 320 Plant Ecology, xiii, 354-7 Plant Families, xiii, 179-207; restricted areas of some, 320 Plant Formations, xiv, 371-2, (see Plant Societies) Plante, ball lightning studies, vii, 215 Planting, index plants, i, 255-6; rules and tables, xiii, 267-97 Planting Machines, v, 244 Plant Kingdom, distinguished from animal, xii, 14-15, xiii, 13-14; history of, xiii, 298-336 Plant Names, xiii, 168-71 Plants, active principle, xiii, 250; adaptations in (see Adaptation to Environment); aerial, xiii, 21; ancient study, 249; animals and, interdependence, viii, 334-5, 347, 349, 350, xiii, 82; autophytic, 96-7; behavior, 76-115; blended characters in, ix, 337; borrowing and robbing, xiii, 97-101; breathing of, 109; Brownian movements, xvi, 166; carbon dioxide used by, i, 13-14, viii, 49; cell constituents of, ix, 26; cellulose of, 30; chemical composition and processes, iii, 344, viii, 335-8, 341, 348, 349, 354-5, xiv, 64-5; chlorophyll (see Chlorophyll); chromosomes in different species, ix, 46; classification (see Plant Classification); climate and, xiv, 363; colorless, xii, 14-15; cultivated (see Cultivated P.); defined, xiii, 13-14; distribution (see Plant Distribution); distinguished, xii, from animals, vii, 14-15; evolution, iii, 249-58; flowering and flowerless (see Flowering, Flowerless Plants); fog drip, i, 351; food and feeding, viii, 339-46, 347, 349, 350, xiii, 13-14, 17-18, 19, 23, 24, 25-6, 39-41, 42, 90-101, xiv, 64-8; food of green and other, xiii, 70; food-making and storage by, viii, 334, ix, 25-30, xiii, 77-84, 95, 96; food varieties for man and animals, ix, 24-5, 30; frost protection, i, 259; frost susceptibilities, 258; galls on, xii, 125; garden (see Garden Plants); geotropism, xiii, 85; growth electrically stimulated, vii, 351-3; growth, upward and downward, xiii, 84-5; guttation, i, 350-1; highly cultivated, xiii, 51; hybrid, 147; immobility, 14, 109-10; index, i, 255; inheritance laws, x, 231, 232; injured, hasty flowering of, xiii, 167; insect-capturing, 39-41; instinct in, xi, 49; land (see Land Plants); light effects on, x, 253; marine, xii, 16-17; microscopic (see Bacteria); modern, origin and development, xiii, 316-25; movements, 109-15; motion pictures of growth, iv, 348; mutation (see Mutants); new species, how developed, xiii, 325-36; nitrogen needs, i, 34, viii, 280, 345-6, xiv, 66; nitrogen supply in soil, x, 193-4; northward movement, xiii, 321; number of species, 323; of oceanic islands, xiv, 277, 278; oils of, ix, 28; parasitic, xiii, 100 (see Parasitic Plants); parts of, 15; petrified, iii, 15-16; phenology, i, 254, 256, 379; protective methods (see Protective Methods); proteins of, ix, 278-9, 280, 287; protoplasm of, xiii, 74; rate of increase in, xv, 19, 21; reasoning in, xiii, 3, 97; reproduction, 116-67 (see Reproduction of Plants); restless and irritable, 109-15; rock disintegration by, viii, 194, 338; rootless, xiii, 15, 21; salt and fresh water, ix, 174, 175; saprophytic, xiii, 99-101; seat of life in, ix, 17; seed-dispersed (see Seed); struggle for dominance (see Struggle for Dominance, Struggle for Existence); sunlight and, ix, 27, xi, 52, xiii, 76-7, 84-90, 361-3, xiv, 365-6, 367; unicellular and multicellular, xiii, 166; uses to man, 9-12, 208-66; variation in, xv, 22-3 (see Variation); vascular and nonvascular, xiii, 65-6; water sources and uses, 90-6, 101-9; water storage, 28, 41-2, 106-7, 378, 379, 380 (see also Vegetation) Plant Societies, xiii, 356-83, xiv, 371-2 Plaskett, reflector of, ii, 106-7 Plaster of Paris, iii, 332, viii, 153; made from gypsum, xiv, 209; manufacture of, iii, 376 Plastic Surgery, x, 57, 189, 384 Plateaus, xiv, 220-4; dissection and destruction, 224; distinguished from plains and mountains, 27-8, 213; formed by warping, 38; mountains from dissected, iii, 139-40, xiv, 225, 226; oceanic, 286; re-elevated, 96-8; topography developed from stratified, 80-1 Plate Condensers, vi, 293-4 Platelets, of blood, ix, 188-9; held by capillary walls, 194 Plates, photographic, viii, 172-3 Platiarius, Joannes, x, 37 Plating of Metals (see Electroplating) Platinum, iii, 335, viii, 126-7, 173-4; affinity intensity, 128; atomic weight and symbol, 383; catalyzer, 82, 103; coefficient of expansion, vi, 265; density of, iv, 113; electrical conductivity, 283; extraction from ores, viii, 131; melting point, iv, 162, viii, 384; occurrence, 131, 198; positiveness of, vi, 59; specific gravity, viii, 384 Platinum Metals, viii, 173 Plato, classifying fault of, x, 83; greatness of, 20; on forms and knowledge, xvi, 87, 88; on passions, xi, 130 Platte River, overloading results, xiv, 161; sediment deposited, iii, 32-3 Platyhelminthes, xii, 44 Plauen Laces, v, 288 Play, of animals and men, ix, 21, xvi, 143 Playfair, xvi, 170 Pleasure, artistic forms of, xv, 296-325; emotions of, ix, 153, 165; significance of, xi, 121-2; stimulation requisite, 195 Pleiades, star cluster, ii, 122, 336; in moving cluster, 343; nebulosity, 110, 359-60 Pleistocene Animals, xii, 279, 306, 313, 327 Plesiosaurs, iii, 288, xii, 182, 202 Pleurisy, friction sounds in, x, 109 Pliny, harvesting machines mentioned by, v, 240; natural history of, xvi, 98; on Roman physicians, x, 25 Pliocene Epoch, species surviving from, xv, 71 Plovers, xii, 262 Plowing, deep, xiv, 69; modern, v, 218, 243 Plows, evolution and kinds, v, 239-40, 241-3, xv, 235-6 Plucker, experiments of, xvi, 193 Plucking of Rock, iii, 29, 64, 65 Plumbago, viii, 43 Plumbing, of houses, how worked, v, 84-6 Plumb Lines, iv, 99 Plumed Seed and Fruits, xiii, 343-4, 345 (see also Winged Seed) Plum Trees, xiii, 197, 271-2 Plums, drupes, xiii, 54; origin, 226; splitting, 94 Plutarch, on rain and battles, i, 336; on sun, ii, 165, 220-1 Plutarch's Lives, Copernicus' study, xvi, 102 Plutonic Rocks, defined, iii, 381, xiv, 105; exposure by denudation, 100, 105; forms, iii, 102 (fig.), 110-12, 170, xiv, 105-11; topography due to, iv, 105-13; weathering of, 105-6, 107, 110, 112-13 Pneuma, x, 27, 29, 63, 85 Pneumatic Breakwaters, v, 125 Pneumatic Caissons, v, 116-21 (see Caissons) Pneumatic Cars, v, 133 Pneumatic Cement Gun, v, 136 Pneumatic Cushions, v, 133-5 Pneumatic Dispatch, i, 29 Pneumatic Drills, i, 27, iv, 129, v, 129, 261-2, 263, 380, 381 Pneumatic Engineering origin, v, 109 Pneumatic Hammer, i, 28, v, 129 Pneumatic Motors, v, 129-30 Pneumatic Musical Toys, of Hero, xvi, 92 Pneumatic Power Transmission, i, 26, 27-8 Pneumatic Riveters, v, 129 Pneumatic School, of medicine, x, 26-7, 29 Pneumatic Shovels, v, 262 Pneumatic Tampers, v, 135 Pneumatic Tires, v, 133-4, 206, 382; bursting by heat, iv, 151 Pneumatic Tools, i, 27-8, iv, 129 Pneumatic Trough, viii, 32 (fig.) Pneumatic Tubes, i, 28-9, iv, 130, v, 137-8; obstructions in, how located, iv, 200 Pneumatic Tunnel Shield, v, 122-4, 260 Pneumogastric Nerve, xi, 30 Pneumonia, x, 288-9; discovery of cocci, xvi, 185; germ of, x, 194, 196, 216, 221, 289; immunity to, 207; inoculation against, 208; negro susceptibility to, xv, 50, 51; toxin of, x, 196 Po (River), levees of, xiv, 53; longitudinal character, 154 Pockels, F., i, 152-3 Pocky Clouds, i, 104, 379 Pocono Plateau, xiv, 221 Podalic Version, x, 56 Podalirius, x, 16 Pods, seed-shooting, xiii, 339 Poetry, development of, xv, 319-22, 325; historic value of, 322, 323-4 Poggendorff's Illusion, xi, 187 Pogonip, ice fog, i, 95-6, 379 Poincaré, astronomical work, ii, 356, 377; on relativity, xvi, 197 Pointed Objects, electric discharges from, i, 157, iv, 265, 269, vi, 295-7 Poiseuille, Jean Leonard Marie, x, 126 Poison Ivy, xiii, 252; aerial roots, 20; family, 200 Poisonous Amphibians, xii, 169-70 Poisonous Gases, in World War, i, 308-9, 313-14, x, 186-7; scars of, 189 Poisonous Snakes, xii, 224-38 Poisonous Spiders, xii, 93, 95 Poisons, arsenic, 169; carbon monoxide, viii, 50-1; diseases from, x, 255; effect on mind, xi, 13; in air, ix, 270; in plants, 30, xiii, 250, 252; mercuric, viii, 170; vegetable acids, 222; wood alcohol, 214; use of, by savages and others, xv, 227-9 Poisson, Simeon Denis, xvi, 122 Pola, harbor of, xiv, 253 Poland and Danzig, xiv, 306 Polar Bands, i, 99 Polar Bears, xii, 336-7; Eskimo method of catching, xv, 224-5 Polar Coordinates, iv, 16 Polarimeter, viii, 226 Polaris (Pole Star), ii, 232; a binary, 123; color, 297; magnitude, 295; standard of magnitude, 297 Polariscope, viii, 309-10, x, 137 Polarity, magnetic, vii, 374 Polarization, meaning, iv, 354, 383 Polarization, in electric cells, iv, 296, 298, 383, vi, 136-7 Polarization of Light, iii, 319, iv, 353-6, 383; discovery, xvi, 119; Pasteur & Le Bel's studies, 163-4; sugar testing by, iv, 354-6, viii, 226 Polar Regions, aurora in, i, 159; clouds and fogs, 93, 95; frozen soil, xiv, 75; halos, i, 179; land areas uncertain, xiv, 11, 20; living conditions in, 344; mirages, i, 172, 173; plant conditions of, xiv, 365; rain and snow in, i, 109, 119, xiv, 42; rime in, i, 121; sky shadows in, 170; tundra vegetation, xiii, 381; winds, i, 127, 128, 129 Polar Relays (telegraphy) vii, 114-18 Polecats, xii, 349 Pole Lathes, v, 42-3 Pole-line Transmission System, vii, 14-24 Poles of Earth, altitude of stratosphere at, i, 20; aurora in relation to, 159; compass in relation to, iv, 246; flattening at, ii, 69; weight of bodies at, 69, iv, 101 (see also Polar Regions) Pole Strength, unit of, iv, 249, 250 Policeman's Whistle, iv, 220 Pollen, xiii, 118, 119; attraction to insects, 124, 125, 134, 143; found in ancient remains, 310; hay fever from, x, 212; in air, i, 61; in aquatic plants, xiii, 149-52; mixtures of, 146-8; protection, 126; "showers," i, 359; wind-blown, xiii, 123, 148-9, 144 (illus.) Pollution Gauge, i, 65, 379 Pollux, angular diameter, ii, 151 Polonium, discovery, xvi, 193 Polyandry, xv, 285, 286-7, 294-5 Polycotyledons, xiii, 60 Polycythemia, x, 152 Polygamy, xv, 285, 287-9 Polymerization, viii, 219, 232, 335 Polynesia, xiv, 277; ease of life in, xv, 124; overpopulation of, xiv, 282 Polynesians, clothes of, xv, 256-7; fire generation by, 231; hair of, 37; in brown race, 37; seamanship of, xiv, 282, 305-6; susceptibility to tuberculosis, xv, 51; tattooing among, 258; wind gods of, 342 Polypeptides, viii, 353 Polypetalae, xiii, 47, 190, 195-201 Polyps, xii, 33-43 Polysaccharides, viii, 224, 227-9 Polyuria, x, 343-4 Polyzoa, xii, 46-7 Pomegranates, origin, xiii, 226 Pompeii, burying of, iii, 100; earthquake at, xiv, 326; volcanic material over, 326 Pomes, xiii, 54 Pondering, delays in brain, xi, 21 Ponds, depth appearances of, iv, 327; dew, i, 352-3 Pond Snails, xii, 69 Pond-weed, xiii, 340 Pons, comet discoveries, ii, 275, 289 Pontchartrain, Lake, xiv, 203 Pontias, i, 131-2, 379 Poor Whites, of southern mountains, xv, 130-1 Popcorn, eating of, ix, 251; known to Indians, xiii, 212 Poplar Trees, antiquity, xiii, 324-5; earliest appearance, 318; family, 191; fluttering of leaves, 113; in landscaping, 271-2; seed dispersal, 343 Popliteal Aneurism, x, 121 Popoff, wireless system, xvi, 191 Poppy, cultivation and uses, xiii, 253-4; seed in confections, 250, 254 Population, artificial selection, xvi, 154-5; civilization in relation to, xv, 128-9; distribution of, 12; increase of, 26-7; mostly on plains, xiv, 218; of mountains, 245 Porbeagles, xii, 145 Porcelain, viii, 283; Egyptian, xvi, 74 Porcupines, xii, 288-9; absence of fear in, xi, 136 Porifera, xii, 30 Pork, calories in, ix, 299; proteins in, 279; trichina caused by, xv, 49; vitamines in, x, 262 Porous Rock, water in, iii, 113-15 Porpoises, xii, 297 Portals of Entry (infections), x, 198, 201-2 Portal Vein, ix, 198, 245 Port Hudson, capture of, xiv, 194 Port Jackson Shark, xii, 143 Portland Cement, iii, 373, 374, viii, 280 Porto Bello, heavy rain, i, 110 Porto Rico, hookworm in, x, 174; ocean depths near, iii, 51; overpopulation of, xiv, 282; zoölogy of, 274 Porto Rico Trench, xiv, 289 Portugal, aphysia dyes of, xii, 68 Portuguese Empire, xiv, 310 Portuguese Language, xv, 162 Portuguese Man-of-War, xii, 18, 37 Portuguese Navigators, xiv, 196, 309 Port Valais, xiv, 53 Position, perception of, xi, 162-3, 164, 165, 167-71 Positive, electrical meaning, vi, 57, 124 Positive Electricity, iv, 258, 265, vi, 287, 288 Positive Ions, i, 142, 143, viii, 121-2 Post, C. W., rain experiments, i, 339 Post, Wright, x, 121 Postage Stamps, dextrin gumming, viii, 228; printing of, vii, 314 Postal Telegraph Company, vii, 108, 112 Post-Mortem Findings, x, 98 Postures, importance to health, x, 241-2; importance of, to right growth, ix, 57; mental effects, xi, 294, 301, 337, 338-40, 371, 372; muscular activity in, ix, 83-4; standing and walking, x, 305 Potash, available supplies and uses, viii, 275, 278-9, 344, xiv, 67-8, 69, 209; from smoke precipitation, vii, 347, 348; in body fluids, ix, 174; in ground water, xiv, 142; locked-up forms, viii, 200-1; salts of, in protoplasm, ix, 82 Potash Lakes, xiv, 206, 212 Potassium, viii, 143-5; affinity strength, 127, 128; alkali metal, 132-4; atomic weight and symbol, 383; fusibility, 384; in body tissues, 354; in earth's crust, iii, 308, viii, 19, 129, 148, 192, 195, 279; light metal, 17, 127; metallic character, 181; plant needs and sources, 337, 341, 342, 343, 344; specific gravity, 384; spectrum, 301-2; test for, 287, 289 Potassium Compounds, viii, 144; chlorate uses, 34, 35, 87, 88, 89, 146; chloride, 188; cyanide, in gold extraction, 174; feldspar, 90; flame color, 301; hydroxide, in soap making, viii, 142; nitrate, 72, 138, 144-5, 146, 372; occurrence in nature, 130, 138, 143-4, 195, 196, 279, 344; permanganate, 294, 333; uses, 130, 144, 146 Potatoes, calories in, ix, 299; eyes of, xiii, 22; food value, ix, 34, viii, 365, x, 261, 265, 266, 268; history and kinds, xiii, 218-19; keeping of, viii, 371; origin, xiii, 221, 223, xiv, 382; starch from, viii, 248, xiii, 83; starch storage in, ix, 27-8; stems, xiii, 22, 23; tubers, 24 (fig.), 83 Potential, Electrical, iv, 262-3, 383, vi, 49, vii, 374; maintenance of constant, vi, 329; positive and negative, iv, 265; spark table, vii, 383 Potential Differences, iv, 263, 383, vi, 50, 51, 57, 72, vii, 366; between earth and clouds, i, 144, iv, 269; electric energy from, 263, 264-5, 294-5; in thunderstorms, i, 149-50, 151-2, vii, 206-7; measured by voltmeters, 154; production of, iv, 271-3; unit of, 280 Potential Energy, iv, 79, vii, 368; conversion to kinetic, iv, 81, 82, 87-8; forms of, 82 Potential Gradient, i, 144, 145 Potential Transformers, vii, 44, 45 Potholes, iii, 39-40 Potomac River, course of, xiv, 154, 168-9; gap, 51, 52, 167; rapids, 159; shad season in, xii, 155 Pott, Percival, x, 92 Pott's Disease, x, 92 Pott's Fracture, x, 92 Potter's Wheel, xv, 249-50, 251 (fig.) Pottery, viii, 282-3; ancient making of, viii, 280-1, xv, 248-51, xvi, 74; decorations of, xv, 250-1, 252, 253, 297-8 Pouched Gophers, xii, 290 Pouched Mice, xii, 278 Poulsen Arc Generators, vii, 274, 275-6, 291 Poultry, originals of, xii, 261 Poultry Products, drain on farm, viii, 342-3 Pound, unit of force and mass, iv, 58, 64-5, 69-70; value in grams, 70, viii, 28 Poundal, unit of force, iv, 64, 69; value in grams and dynes, 70 "Poverty Year," i, 359 Powder (see Gunpowder, Smokeless Powder) Power, defined, iv, 80, vi, 83, 84; electric (see Electric Power); from fuels, ix, 15-16; gain in elementary machines, v, 22-3, 31-5, 38; relation to velocity in machines, iv, 92; sources of, ix, 25-6; unit of, iv, 80, vi, 83, 84, vii, 369 (see also Energy, Force) Power Boats, cylinders, v, 159 Power Factor, in alternating currents, vi, 169, 172; in induction motors, 255-6; regulation by, synchronous motors, 255, 260-2; in rotary converters, 348 Power Plants, vi, 349-84; distribution of power, vii, 25-31 (see also Power Transmission); extra charges for peak hours, vii, 177-8; for farms, 231-4; high and low head, v, 79-83; interest of machinery, vi, 175-6; number and capacity in U. S., vii, 74-5; remote control in, vi, 100-1, 102; Shuman's sun-using, v, 177-8; tidal, 174-7; turbine use, advantages, 151, 153; use of alternators, vi, 215; using volcanic heat, v, 179-80 (see also Hydroelectric Plants) Power Transmission (electrical), vii, 9-31; alternating currents in, vi, 159-61, 169, 195-6; direct currents in, 160, 195; Niagara Plant system, 375-8; overhead and underground (see Overhead, Underground Transmission); present distances attained, 365; problem, 367-8; prominent names in history, 26; synchronous condensers in, 262; traction methods, vii, 186-93, 197-200; voltages and currents used, vi, 159, 160-1, 163, 169, 331-2, vii, 10-11 (see also Long Distance Transmission) Power Transmission (Hydraulic), v, 104-8 Power Transmission (pneumatic), i, 26, 27-9 Practice, effects of, xi, 253 Praepositus, Nicolaus, x, 37 Præsepe, star cluster, ii, 336 Pragmatic Philosophy, xvi, 196 Prairie Dogs, xii, 294 Prairie Fires, smoke from, i, 56 Prairies, dominance of grasses on, xiii, 350; plant societies of, 373-6; soils of, xiv, 383; United States, 374, xiv, 373; windbreaks, i, 333 Prase, iii, 337 Praseodymium, symbol and atomic weight, viii, 383 Prayer, primitive conceptions of, xv, 344-7 Pre-Babylonian Science, xvi, 56-63 Precession, of gyroscopes, v, 336, 337-9, 340, 341, 342 Precession of Equinoxes, ii, 70-1; Arab work on, 38; discovery, xvi, 90; Hipparchus on, ii, 31, 300 Precipitate, defined, viii, 380 Precipitation (atmospheric), annual amount, xiv, 135; climate determined by, 351-2, 355-6; measurement, i, 79-82; mountain effects, xiv, 354-5; source of terrestrial waters, 134, 151; various kinds, i, 106-22, 379 Precipitation (electrical), vi, 164, vii, 216, 346-51 Precipitation Treaters, vii, 348-51 Prehistoric Man (see Primitive Man) Prehistoric Times, before writing, xv, 167, 322-3; geographical and climate changes since, xiv, 29-30 Prejudice (see Bias) Preoccupation, of mind, xi, 154-5 Prepotent Inheritance, x, 230 Preservatives, action of, viii, 333; chemical, 372 Preserving of Foods, viii, 371; effect on vitamines, x, 263, 266 Pressure, boiling point and, iv, 167-8, 169-70; critical, 171-3; melting point and, 153, 162, 163-6; sense of, xi, 109, 110, 111, 113, 114 (see also Atmospheric Pressure, Gases, Liquids) Pressure Areas, ordinary movement, i, 237; physiological effects of alternations, 329-30; wind and weather attendants, 125, 134-5, 218, 237-8, xiv, 349-50 (see also Highs, Lows) Pressure Belts, i, 127-9 Pressure Cookers, iv, 171 Pressure Gradients, i, 126, 373; reversal, 130, 131 Pressure Waves, in alternating currents, vi, 198 Prevailing Westerlies, i, 128, 379, xiv, 345-6, 349 Preventive Medicine, x, 282-317; history of development of, 15, 99, 133-4, 171-6, 217-18 Prickly Fruits, xiii, 58, 343 Priestley, chemical work, xvi, 120, 177; oxygen discovery, viii, 34, x, 89, xiv, 65 Priests, of savages, xv, 349-53, 354, 359 Primary Cells, iv, 299, 383, vi, 130, 131-44, vii, 363; chemical action of, viii, 167 Primary Coils, iv, 383, importance of knowledge of, 9 Primary Colors, iv, 366 Primary Concepts, iv, 14-16 Primary Rocks, viii, 191; disintegration, 194-5 Primates, iii, 301, 302, xii, 373-4, 375, xvi, 126 Prime Movers, ix, 15, vii, 373; of future, v, 171-81; various kinds, vi, 181-2, 351-2 Primitive Man, æsthetic arts of, xv, 296-325; conditions of life, x, 10, xv, 188-92; dogs of, xii, 345-6; language of, xv, 140; love of decoration in, 252-3; mind and beliefs, xvi, 42, 43-5, 51, 56; religion of, xv, 327-59; sex relations of, 277-8; tools and weapons of, v, 11, 12-15, xv, 102-10; types of, 77-102 (see also Cave Men, Savages) Primrose, leaves, xiii, 88; petals, 190 Primrose Family, xiii, 203-4 Prince Rupert Drops, viii, 281 Princeton College, founding, xvi, 127 Prince's Island, groundsel in, xiii, 345 Principle of Archimedes, iv, 30, 102-5; applicable to gases, 107, 126 Pringle, John, x, 104, 155 Print, machines to read, v, 332-5, 384 Printing, v, 300-13; color, iv, 370-1; electrotyping, vii, 313-14; invention of, xv, 179; invention, results on science, ii, 13, 40, 42, x, 44; photographic, viii, 173 Printing Presses, development, v, 300-5, 378, 379, 381 Prisms, effect on light, i, 165, ii, 99, 111, 112, iv, 357-9, 365, viii, 301 Prisoners, habit in, xi, 255; labor of, 275 Privet, leaf arrangement, xiii, 38 Proboscis, of insects, xiii, 126 Proctor, astronomer, ii, 249, 343 Procyon, ii, 297, 319 Prodigality of Nature, in ferns, xiii, 155, 156; to insure reproduction, 117, 118, 124, 152 Produce Exchanges, weather reports at, i, 252 Professional Men, food requirements, ix, 297 Proficiency, unconsciousness of, xi, 254 Profiteers, and farmers, vii, 220, 221 Prognathic Angle, xv, 44 (fig.) Prognosis, Hippocrates on, x, 78 Progress, cumulativeness of, xvi, 41; due to experience of past, ix, 153, xv, 30-1; due to individuals, xi, 333; in organic life, xvi, 152; language and, xv, 68, 145-6; rhythm in, xvi, 46, 116; scientific (see Science, progress); summary of mechanical, v, 376-84; transportation and, 18 Projectiles, atmospheric resistance, v, 369; explosives for throwing, viii, 260-1; flight, i, 312-13; from aeroplanes, v, 372-3; handling on battleships, vii, 334; meteorological corrections, i, 312-13; sound, i, 193-4; World War, v, 372 Prometheus, story of, viii, 89 Promontories, formation of, xiv, 256 Pronghorns, xii, 322-3 Proof by Induction, xi, 242 Propane, viii, 210 Propellers, iv, 34; electric drives, v, 105-6, 153-4; mechanical and electric drives, vii, 329-30; most efficient speed, 329; of early steamboats, v, 189-90; suction applications of, iv, 127 Proper Motion of Stars, ii, 121-2, 304-5; determined by spectrum analysis, 119-20; Eddington on, 344; Halley's discovery of, 84, 86-7; in relation to spectral type, 307-9; origin, 308 Property, inheritance systems, xv, 289-90, 294 Prophylaxis, x, 213, 318 (see Immunity) Propionic Acid, viii, 220 Proportional, defined, iv, 63 Proprioceptive Senses, xi, 63 Propyl Alcohol, boiling point, viii, 212, 299 Propylene Glycol, boiling point, viii, 299 Prosauria, xii, 182, 183, 203 Prosepny, geological work, xvi, 172-3 Protagoras, on relativity, xvi, 85, 87; theory of knowledge, 87 Proteases, viii, 357 Protective Coloration, xv, 17-18; in amphibians, xii, 170; in birds, 245-6; in lizards, 204; in lions and tigers, 359-60; in rabbits, 287 Protective Devices (electrical), vii, 32-50 Protective Methods in Plants, flower buds, xiii, 45; leaf-buds, 34; leaves, against sunlight, 89; leaves, hairy covering, 104-5; nettles against animals, 42 Protective Motions, of animals, ix, 21 Proteins, viii, 380; amount in daily diet, 366-7, ix, 300-1; amount needed in foods, ix, 281-4, x, 255-6, 278-9; anaphylaxis from injection of, x, 213, 214, 223; animal and plant, ix, 278-9, 280, 287; animal and plant percentages, viii, 348, 349, 351; antigenic properties of, x, 205; body heat production by, ix, 309; body needs of, ix, 33, 34-5, 278, 287-8, x, 255-6, 277-8, xi, 279; body percentage, viii, 348; calories in, 361, x, 269; chemical composition and properties, viii, 351-2, 357, ix, 29, 279, 287; classification, viii, 352-3; different kinds, ix, 278-9; digestion and utilization of, 235, 242, 243, 244, 245, 279-84, x, 204, 270, 277-80, 319, 326, 329, 330, 342; energy value, ix, 300; excess of, in food, 283-6; human, 279, 280, 287; in blood, 176-7, 181, 183, 184, 194-5; injections of, effects, x, 204, 213, 214, 223; injections of, in therapy, 226; in plants, iii, 344, viii, 348, 349, 350, 351, ix, 278, 280, 287; in protoplasm, 32-3, 34, 278; in various foods, viii, 362, 363, 364, 366, ix, 300, xiii, 213; likeness and differences, ix, 278-9; making of, by plants, viii, 336, 349, 350, ix, 29, 278, xiii, 95; metabolism effects, ix, 301-2; molecular structure, viii, 217-18; need of, in diet, x, 255-6, 268, 278-9; nitrogen in, viii, 64-5, 73, 340, x, 270, 277, 342; plant, ix, 278-9, 280, 287; plant percentages, viii, 348, 349, 351; storage of, by body, x, 272; wool and silk as, viii, 256 Proterozoic Era, iii, 20, 174-8; plants and animals, 251, 261-2, 262-3, 264-5, 270, 271, 276 Proterozoic Rocks, iii, 174-8 Prothallus, xiii, 157, 158, 160, 162 Protonema, xiii, 156, 162, 163 Protoplasm, x, 228; basis of life, ix, 13, 17, x, 228, xiii, 74; body percentage of, ix, 31; chemical composition and processes, viii, 356, ix, 32-3, 34, xvi, 155; chlorophyll and, xii, 14; color in nerve cells, ix, 124; conditions necessary to, ii, 243; constitution and functions, ix, 41-3; control of activities of, 39-40; differences of, in plants and animals, 278-9; inactivity when cooled, 306-7; maintenance and growth, 34-6, 278-84; making of new, 32, 33, 38-9, 287-8; motion by, 73; occurrence and nature, xii, 13; origin of, xiii, 300; salts in relation to, ix, 32, 174; signs of life, 13-17; studies of, xvi, 166; wastage of, in body, ix, 34, 282-3; water in, effects on metabolism, 37-8 Protopterus (fish), xii, 166 Prototheria, xii, 271, 272-4 Protozoa, iii, 259, 263, 265-6, xii, 25, 26; disease-producing, x, 199, 200, 204; in plankton, xvi, 147; origin of, xii, 12; reproduction in, 26 Prout's Hypothesis, viii, 177, 187 Prunes, as antiscorbutic, x, 266; eating of, ix, 251 Prussia, vaccination in, x, 103 Pruth River, xiv, 185 Psuchrainometer, i, 319, 379 Psyche, xvi, 17 Psychiatry, x, 356, 357 Psychic States, motor character, xi, 58-9, 61 Psychor Analysis, x, 243, 363-5 PSYCHOLOGY, Volume xi Psychology, complexity of science of, x, 368; concrete science, xvi, 42; daily applications, 17-19; defined, 37, xi, 10-14; field of applied, 9-10, 367; medicine and, x, 369; origin of name, xvi, 17 Psycho-neuroses, x, 359-60 Psychoses, of adolescence, x, 236-7 Psychrometers, i, 78-9, 379 Pteranodons, iii, 294 Pteridophytes, iii, 251, 252, 253, 256 Pteridosperms, iii, 251, 252, 254-5 Pterodactyls, xii, 202, 203 (fig.) Pteropoda, xii, 18, 19 Pterosauria, xii, 182, 202 Ptolemaic System, ii, 10, 34-6, xvi, 93; Bacon's criticisms, 101; Copernicus and, ii, 49; dissatisfaction with, 40, 42; Galileo and, 54; Regiomontanus and, 40; persistence, 45 Ptolemy, ii, 32; Almagest, 10, 33-6; Aristotle and, 42; conception of moving bodies, 63; debt to earlier astronomers, 29; ideas of cosmos, 367; remarks on geography of, xiv, 3; works of, xvi, 93-4 Ptomaines, viii, 215 Ptyalin, ix, 230, 235-6 Puberty, mental diseases following, x, 236-7; need of health instruction at, 283 Public Halls, ventilation methods, ix, 269 Public Health, campaign for, x, 171, 172; science of, viii, 317-33 Public Health Service, U. S., x, 190-1 Public Lands, (U. S.), xiv, 384 Public Opinion, power of, xv, 374-5, 380 Public Speakers, and audiences, xi, 216; pitch of voice in, iv, 232 Puccini, reference to, xv, 297 Pudding-stone, sedimentary rock, xiv, 18 Puddled Clay, xiv, 137 Puddling Process, invention, v, 316-17 Pueblo Pottery, xv, 249 (fig.) Puerperal Fever, x, 114-15 Puff Adder, xii, 231-2 Puffballs, fungous, xiii, 71 Puffins, xii, 264-5 Puget Sound, harbors of, xiv, 268; salmon in, xii, 157 Pugnacity, derivation of word, xi, 43-4; instinct of, 56 Pulleys, v, 33-5; action of, like levers, iv, 89; friction in, 93 Pull-out Loads, of motors, vi, 260 Pulmonary Artery, ix, 199, 201 (fig.); capillaries of, 254; elasticity of, 210 Pulmonary Vein, ix, 199, 201 (fig.); blood in, 260 Pulmonates, xii, 68-71 Pulp, in paper-making, v, 291-5 Pulse, ix, 211; former ideas of, x, 62, 63; Galileo's measurement, v, 64-5; rate of, x, 334 Pulsilogia, Galileo's, v, 65 Pumas, xii, 363-4 Pumice, from Krakatoa eruption, iii, 101, xiv, 325; in ocean, iii, 55, xiv, 285-6 Pumpelly, climate studies, xiv, 29, 361; on loess accumulations, 73-5 Pumpkin, xiii, 54-5, 223 Pumps, centrifugal, vi, 363; chain, iv, 26; electric and automatic, vi, 99-100, vii, 86-7; for deep wells, v, 114-15; force, 113-14; suction, 112-13; reciprocating, motors used, vi, 234; suction, iv, 26-7, 126 Punching Machines, chisel form, v, 46; motors used, vi, 235 Pupil, of eye, ix, 109, 110 (fig.); dilation of, in fear, 166; size changed by smooth muscle, 162 Purbach of Vienna, ii, 40 Purchase, marriage by, xv, 283-5 Pure Breeds, in animal breeding, ix, 337; from crosses, 335, 336 Pure Food Law, viii, 370 Puritanism, suppression of emotions, xi, 140 Purmann, Matthaeus, x, 78 Purple Dyes, sources of, xii, 68, 72 Purple Light, of sunsets, i, 167, 379-80 Purple Loosestrife, xiii, 140-1 Purpose, motor character, xi, 61 (see Will) Purslane, xiii, 15 Pus, formation of, ix, 186-7; former conception of, x, 39-40, 41, 43; modern attitude towards, 145, 147 Pus Pockets, ix, 187, 188 Pus-producing Germs, ix, 186-8, x, 195, xiii, 71; infections by, x, 198, 207, 221; vaccination against, 218 Putrefaction, cause, xvi, 143; intestinal, ix, 249-50 Pycraft, Prof., on chameleons, xii, 209-10 Pyemia, x, 198 Pygmies of Africa, xv, 38-9 Pyorrhea, of gums, x, 202, 219, 222 Pyramids of Egypt, ii, 24, xv, 269-71; civilization exhibited, xvi, 66-7, 71; orientation, ii, 26; rocks used in, iii, 235; weathering of, xiv, 78 Pyrene Extinguisher, vi, 101 Pyrenees Mts., as barrier between Spain and France, xiv, 239-40; geranium of, xiii, 136; geological history, iii, 235, 236, 240; recent formation, xiv, 235 Pyrheliometer, i, 88, 380 Pyridine, viii, 240, 253 Pyrite, iii, 335-6; gold in, 366 (see also Iron Pyrites) Pyrogallol, viii, 288 Pyrosoma, xii, 19-20 Pyroxene, composition of, viii, 193 Pyroxene Group, iii, 336 Psycho-Analysis, x, 243, 363-5 Pythagoras, conception of universe, ii, 10, 42-3, xvi, 80, 81-2; mathematics of, 79-81; medical work of, x, 17-18 Pythagorean Theory, xvi, 81-2 Pythonomorpha, xii, 182, 202-3 Pythons, xii, 213-15 Qobar, i, 380 Quacks, Barton on, x, 76, 367, 374-5; cures of, vii, 240-1 Quadruplex Telegraphy, vii, 112, 117 Quagga, xii, 308 Quahogs, xii, 66-7 Quails, xii, 261 Qualitative Analysis, viii, 285-91 Quantitative Analysis, viii, 285, 291-5 Quantum Dynamic Theory, xvi, 134-5 Quarrying, in ancient Egypt, xvi, 67-8; joints in, xiv, 128-9 Quart, compared with liter, viii, 28 Quartz, iii, 336-8; fused, manufacture and uses, vii, 311-12; gangue mineral, viii, 199; gold found with, iii, 366, 367; in granite, 27, 308; in iron ore, 356; in soils, 27, 28; insolubility, viii, 112 Quartzite, iii, 381; origin, 169, 189 Quaternary Period, iii, 20, 236-48; appearance of man, 302, 303, xv, 72; differentiation of races in, 95; divisions of, 71; Ice Age (see Ice Age) Quaternion Analysis, invention, ii, 72 Quatrefages, morphology studies, xvi, 140-1 Quebec, harbor of, xiv, 270; plateau of, 221, 236 Quebec Bridge, construction, v, 100-1 Queen Anne's Lace Plant, xiii, 201 Queensland, barramunda of, xii, 165 Queensland Hemp, xiii, 244 Questions, suggestion by form of, xi, 308-10 Quetelet, xvi, 153 Quicklime, iii, 373, viii, 149-50 Quickness, in different types of men, xi, 156-9 Quicksand, excavating through, v, 115-18, 123 Quicksilver (see Mercury) Quinces, origin, xiii, 226 Quinine, an alkaloid, viii, 240; from tropical forests, xiv, 383; history and production, xiii, 250-2; importance of discovery, 9; sulphate of, iv, 356, 379; use in malaria, x, 154-5, 158, 381 Quipus, xv, 165 (fig.), 166 Ra, Egyptian sun-god, ii, 24; horns of, xii, 326 Rabbits, xii, 286-8; direction perception by, ix, 117; embryological development, xv, 55; fear in, xi, 136; heart of, x, 332; nest-making by, xi, 56; protective coloration in, xv, 17, 18; rate of increase and destructiveness, 20 Rabelais, François, x, 45 Rabies, germ of, x, 200; Pasteur's cure of, 141, 142-3 Raccoon Creek, Ohio, xiv, 185 Raceme, flower form, xiii, 50 Racemic Acid, Pasteur's studies of, x, 137 Racers (snakes), xii, 218, 219, 220 Races of Mankind, xv, 32-4; brain and skull, differences, 41-3, 62; contact of inferior, xvi, 50; characteristic diseases, xv, 47-52; differences in, due to proteins, ix, 279; European, xvi, 48-50; extinction of, xv, 98-9; intermixture of, 32, 35-6; language and, 159; mental characteristics, 36; physical characteristics, 36-47; separate origin theory, 69-70; subdivisions of, xiii, 173; type characters, 34-6; vanished and weak, xvi, 64 Races, Tidal, xiv, 294 Race Type, xv, 34-5 Racing Cars, speed, v, 214 Radial Velocities of Stars, ii, 120, 122; of nearest stars, 319; of star clusters, 337, 339; photographic study, 137, 158-9 Radiant Energy, iv, 322, 366, ix, 114-15; of sun and stars, ii, 170, 383-4, iv, 181-2, 194 (see also Radiation) Radiant Matter, iv, 54-5 Radiation, heat, iv, 180-4, 366; light production by various kinds, of, 378-80; penetrating, i, 143-4, 146, 379; terrestrial, volcanic dust effects, 59; therapeutical uses of, x, 383 Radiation Emanation, vi, 269-70 Radiative Equilibrium of sun and stars, ii, 382, 383-4 Radiators, heat of, iv, 186, 187 Radicals, Chemical, viii, 93, 380; method of expressing, xvi, 160-1; valences of, viii, 94 (see also Groups) Radioactive Substances, viii, 184-9; emanations of, i, 143, 330; fluorescence produced by, iv, 380; helium produced by, xvi, 194; in nature, i, 143, xvi, 193; ionization by, i, 143-4 Radioactivity, viii, 184-9, 307; climatic effects, i, 211; discovery of, iv, 55, xvi, 165, 193; explained by electron theory, iv, 23; of meteorites, ii, 292; light theory, iv, 50; physical phenomena of, viii, 307 Radio Communication, vii, 258-98 (see also Wireless) Radio Compass, i, 191 Radio Control, of aeroplanes and ships, vii, 283-4 Radio Corporation of America, vii, 274-5 Radio Generators, vii, 273-8; in aeroplanes, 282-3 Radiographs, X-ray, vii, 253-4, x, 185-6 Radiolarians, xii, 17-18; in plankton, xvi, 147 Radio Stations, aeronautical services, i, 292; distress signal system, vii, 284; intercommunication, 261; remote control from, 283-4; weather reporting, i, 281, 282 Radio Theory, vii, 285-98 Radiotherapy, x, 383-4 Radio Waves, conversion by vacuum tubes, vi, 339-41; damped and undamped, vii, 273-4, 289-90; generation and detection, iv, 314-15, vi, 163, 215, vii, 273-8, 286-91, 293-8; generation in aeroplanes, 282-3; length, iv, 315, vi, 269, vii, 260; length, by what determined, 266; lengths used, 272, 274, 275; measurement of length and frequency, 291-5; measured in meters, 272; remote control by, 283-4; transmission, 261, 263-73, 278-80 (see also Radio Communication); vibrations in æther, vi, 119, 163, vii, 250 Radish, xiii, 197, 223 Radium, viii, 184-5, 186; atomic weight and symbol, 383; discovery and occurrence, xvi, 193; disintegration into niton, viii, 185; emanation (see Niton); energy from disintegration, viii, 186-7; fluorescence and luminosity from, iv, 380; increase, xvi, 194; in soil, i, 143; therapeutic uses of, x, 383-4 Radium Compounds, viii, 184 Radium Watch Dials, iv, 380 Radius Vector, ii, 51 Raffia, origin and product, xiii, 244 Raffles, Sir Stanford, xiii, 363 Rafflesia Arnoldii, xiii, 364; illustration, 352 Rafts, xv, 264-5 Rage, emotion of, xi, 138, 139 Rags, paper from, v, 290-1, 292 Ragweed, pollen of, xiii, 118 Rahbeg, Arabia, charting of harbor, i, 47 Rahu, Chinese dragon, ii, 209 Railroads, air brakes on, iv, 129, v, 130-2; block signal systems, vii, 355-9; coal using, v, 172; early, 207, 208, 377, 378-9; effects on rivers and water power, xiv, 31, 191; electrification (see Electrification of Railroad); in tropical regions, xiii, 359; present inadequacy, vii, 194-5; snow removal, i, 117; weather and climate problems, 267-8 Railroad Terminals, electrification, vi, 162, vii, 181-2, 193, 197-8 Railroad Ties, walking on, ix, 89 Railroad Tracks, expansion by heat, iv, 134; outer rail on curves, 73; pneumatic tamping, v, 135; reduction of friction, 206; sound transmission by, iv, 199; traction of, v, 207 Rails (birds), xii, 261-2 Rails (Railroad), manufacture of, v, 322-3 Rain, i, 108-9; artificial production, 332, 333-4, 336-40, 345; "blood showers," 55; business effects, 264, 265; dust depositing by, 55; explanation, 93; formation of drops, 112-13; formation in hot afternoon storms, vii, 217; from cloudless, sky, 119; gray suit sets and, 166; large drops in thunderstorms, vii, 215-17; low pressure areas and, i, 237; no region without, 210; rainbow predictions, 177; red, 358; rock-weathering by, xiv, 39, 41-2, 49, 62, 63, 77, 105-6; salt deposited, by, i, 59-60; sounds as prognostics of, 187; yellow, 61 (see also Raindrops, Rainfall) Rain Balls, i, 104, 380 Rainbow, i, 175-7, 380, iv, 374-6; colors of, ix, 115; Keats on, i, 346 Rain Clouds (see Nimbus, Cumulo-Nimbus Clouds) Raindrops, formation, i, 112-13; rainbows due to, 175, 176; size, 113-14; speed of fall, 113, 114 Rainey, George, xvi, 145 Rainfall, i, 380; ascending air currents and, xiv, 354-6; changes in historic period, 362; climate determined by, 351-2, 355-6; corn-crops and, i, 247, 248; distribution and intensity, 109-12, 208; economic importance, 263; examples of excessive, 109-11, 111-12; forests dependent on, xiii, 367, 372, 373-4, 376, xiv, 377-8, 379; in desert regions, xiii, 377, 380; in tropical forests, 358, 360; measurement, i, 79-82; measurements, ancient, i, 68; mountains and, 111, xiv, 354-6; plant types determined by, xiii, 357-8, xiv, 369; soil elements affected by, 68-9; solar radiation and, ii, 187-8; sun-spots and, 186; statistics, importance of, i, 110-11; water in inch of, 109; water table dependent on, xiv, 136 (see also Precipitation) Rainfall Charts, i, 206 Rain Forests, xiii, 358-66, 372, xiv, 368-9 Rain Gauges, i, 68-9; kinds and uses, 80-2, 380; on Mt. Waialeale, 112 Rain Gods, Australian, xv, 195 Rainier, Mount, xiv, 225; beauty of, 100-1, 315; glaciers of, iii, 60-1; snow honeycombs, i, 117; vapors of, xiv, 313, 314; volcanic origin, iii, 106, 226 Rain Insurance, i, 270 Rain-making (see Rain, artificial production) Rains, curious, i, 355-9; of toads, xii, 177 Rainstorms, gathering of, viii, 304; water in, 109-10 Rain Tree, i, 349-52, 380 Rain Water, nitrogen compounds in, i, 13 Rainy Regions, factors determining, i, 111 Rainy Weather, splitting of tomatoes in, xiii, 94 Raisins, eating of, ix, 251 Rakers, automatic, v, 246, 247, 379 Raleigh, Sir Walter, introduction of potato by, xiii, 218 Rameses, monument, xvi, 67; sacrifice made by, xv, 347 Ramie, cellulose composition, viii, 254; origin and product, xiii, 244 Rams, horns of, xii, 325-6 Ramsay, Sir William, discovery of elements, i, 12; discovery of argon, viii, 67; helium discovery, xvi, 194 Ranches, cattle, xiv, 383-4 Range Finders, principle, xi, 179-80 Ranges, electric, vii, 88-9 Rankin, Angus, quoted, i, 158 Raoulia Cushions, xiii, 379-80 Raphael, anatomy advanced by, x, 51-2 Rapids, in new and old regions, xiv, 48, 49 Rapid Sand Filters, viii, 320 Rare Earths, viii, 182 Raspberries, origin, xiii, 226 Rate, technically defined, iv, 383 Ratings, of electrical machines, vi, 192-4, 212, 317 Rationalizations, xi, 244-5 Ratite Birds, xii, 243, 249 Rats, xii, 289-91; bubonic plague and, x, 163, 165-7; cannibalism of, ix, 280-1; dangerousness of, 12, 285-6; sleeping sickness organism in, x, 168; snakes and, xii, 219, 220, 222; war against, x, 171 Rattan Cane, xiii, 244 Rattan Palm, xiii, 27, 361, xiv, 368 Rattlesnakes, xii, 234-8; prairie dogs and, 227; tongue of, 212 Ravenna, formerly on coast, xiv, 53 Raw materials of Plant Life, xiii, 79; Sources of, 80, 81 Ray, natural history work, xvi, 116, 126 Ray Flowers, xiii, 206 Rayleigh, Lord, discovery of argon, i, 12, viii, 67; light theory, xvi, 137-8; on ultra-violet light, i, 16; sound studies of, iv, 52 Rays (fish), xii, 148-50; eyes of, 138 Rays, of flowers, xiii, 44, (fig.), 49; of light and electricity, iv, 383 Razor Fish, xii, 59 Reactance, condenser, vi, 171; current-limiting, vii, 49; inductive, vi, 170; in alternating currents, 170, 172; in induction motors, 248; in oscillating circuits, vii, 289 Reaction, principle of equal, v, 143-4 (see Action and Reaction) Reactions (physical) outgoing and withdrawing, xi, 54-6 (see also Motor Responses) Reaction Types and Times, xi, 152-9 Reactors, current-limiting, vii, 49 Read, Commander, on aeroplane safety, i, 50 Reading Glasses, ix, 111 Reading Machines, v, 332-5 Reagent, defined, viii, 381 Reality, Aristotle on, xvi, 88; in pragmatic philosophy, 196 Reaping Machines, v, 240, 244-9, 379 Reason, Reasoning, xi, 237-46; in man and animals, xv, 65-6, 67-8; in sleep, xi, 286, 287; instinctive, 46, 47; meanings of, 233-4, 237-9 Rèaumur, René, A. F. de, x, 88, xvi, 174; thermometer, scale of, iv, 136, 137 Rebus, game of, xv, 168-9 Receivers, telephone, vii, 94, 96-7 Recency, in associations, xi, 204-5 Receptacle (botanical), xiii, 153 Reception Halls, lighting, vii, 70-1 Receptor Neurones, xi, 21, 22, 26, 27, 30; in embryo, 34, 35 Receptor Organs, of various senses, xi, 63, 116-17 Recessional Moraines, iii, 67 Recession of Spring Heads, xiv, 176 Recessives, in crosses, x, 231 Reciprocal Accumulation, vi, 298 Reciprocal Innervation, xi, 86 Reciprocating Engines, compared with turbines, v, 152-3; control, 153; disadvantages, 148; waste of heat energy, 155 Recoloration (see Afterglow) Recording Meters, vii, 177-8 Recreation, psychology of, xi, 269-70 Rectifiers, mineral contact, vii, 268-9; mercury arc, vi, 331, 333-9; vacuum tube, 339-41 Rectilinear Coordinates, iv, 16 Recurrence, Weather, i, 362-3, 380 Recurrent Images, xi, 221 Red, complementary color of, iv, 367; effects of blood pressure, xi, 63; heat colors, iv, 361; of sunset and rise, i, 166, 168; penetration of ocean by, xii, 22; primary color, iv, 366; seeing of, in color-blindness, ix, 116; stimulating effects, vi, 274; vibration rate, ix, 115; wave lengths, i, 165, iv, 360, 365 Red Beds, iii, 202, 204, 208 Red Cedar, spread, xiii, 340 Red Clay, on sea floor, iii, 54, xiv, 285, 286 Red Coral, xii, 43 Red Corpuscles, ix, 181-4, 275; blood transfusion in relation to, x, 338; carbon monoxide effects on, viii, 50-1; held by capillary walls, ix, 194; oxygen-carrying by, ix, 182-3, 258-9, x, 338-9; reduced in anemia, 337 Red Cross, Pringle's idea, x, 104 Red Crust Polyzoans, xii, 47 Redfield, W. C., i, 215 Red Fire, viii, 301 Red Flash, of sun, i, 171 Red Hot, temperature of, iv, 361 Redi, Francesco, xvi, 114 Red Lead, viii, 162 Red Light, photographic uses, viii, 171 Red Marrow, ix, 183 Red Pepper, source, xiii, 221 Red Race, xv, 32, 37; diseases of, 51; separate origin theory, 70 Red Rain, i, 358 Red River of the North, xiv, 158, 201 Red Sea, in Great Rift Valley, xiv, 117-18; origin of color, xvi, 147; salt in, viii, 139, xiv, 296-7; sharks of, xii, 145 Red Snow, i, 358 Red Test, of kidneys, x, 378 Red Thread (worm), xii, 54 Reduction (chemical), viii, 381 Redwood Forests, fog drip, i, 351 Redwoods, former distribution, xiii, 320; of California, xiv, 374 Reed, Dr. Walter, x, 160, 162, 200 Reed Instruments, iv, 284-5 Reed Boat, xv, 264 (fig.) Reefs, oceanic, defined, xiv, 286; of seaweed deposits, iii, 250, 251 (see also Coral Reefs) Refining of Metals, viii, 272 (see also Electro-Refining) Reflection of Light, iv, 324-5, 330-1; by mirrors, 335-7; total, 373-4 Reflectors (heat), iv, 182 Reflex Actions, ix, 185-6, 258, xi, 20, 26-7, 62-3, xv, 65; development in embryo, xi, 35-6; grasping reflex, 40-3; hypnotic suggestion of, 317; in glands and smooth muscle, ix, 163; in infants, 349; in vasomotor system, 311; in sleep, xi, 26-7, 286; instincts as, 48; law of final common path, 22; mind as sum of, 23-5; shivering, ix, 309-10; some special, 155-9, 163, 168-72 (see also Chain Reflex, Circular Reflex, Conditioned Reflex) Reflex Arc, x, 20-8; time factors, 154 Refracting Telescopes, ii, 96-101, 103-4, 108, 202 Refraction of Light, iv, 325, 326-9, 330, 331, 373-4; astronomical, i, 167, 380; by lenses, iv, 337-9; index of, in chemical analysis, viii, 310; Newton and Huygens' studies, xvi, 119; terrestrial, i, 171, 380 Refraction of Sound, iv, 286-7 Refractories, furnace, vii, 306-8 Refractory Phase, of nervous excitation, xi, 21 Refrigerating Machines, v, 346-7, 350, 351-8, 380, vii, 85-6, viii, 59 Refrigeration, ammonia system, iv, 187-8; battleship system, 331-2; domestic, 85, 86; electric, 85, 229-30; evaporation methods, iv, 174, 187; expansion and brine methods, vii, 85-6, 328; freezing mixtures and solutions, iv, 175; ice, iv, 178; ice, objections to, vii, 230; liquid air, i, 30, 31-2; salt used in, viii, 140 (see also Refrigerating Machines) Refrigerator Cars, v, 346-7 Regelation, iv, 165-6, 383 Regeneration, power of, xii, 170 Regenerative Brakes, vii, 200 Regiomontanus, ii, 13, 40-1 Regnault's Constant, iv, 142 Regular Coasts, xiv, 250-2, 256, 262; unfavorable to commerce, 265 Regulators, Induction, vi, 328-9, 346 Regulus (star), ii, 295 Rehabilitation, of World War disabled, x, 189-91 Rehoboam, wives of, xv, 289 Reign of Algæ, xiii, 314, 323 Reincarnation, belief in, xv, 333, 334 Reindeer, xii, 319-20; horns of, 316; in glacial period, xiv, 376; in Cro-Magnon art, xv, 114; relics of, in Spain, 100 (fig.) Reindeer Moss, xii, 320 Reinhold, astronomical tables, ii, 44 Reis, telephone of, vii, 92 Rejuvenation (geological), definition, iii, 36, 381; examples, 219, 230, 231, 232-3; of folded areas, xiv, 96-8 (see also Elevation) Reka River, xiv, 150 Relapsing Fever, diagnosis of, x, 216 Relative Time, Newton on, iv, 15 Relative Wind, i, 289, 299, 380 Relativity, doctrine of, iv, 16-18; Einstein theory, ii, 80-2, xvi, 196-8; of knowledge and perception, 85, 87, 195-6; of motion, 12, 85 Relaxation, xi, 339-40, 371-2; after meals, 374-5 Relay Circuits, vii, 39-48 Relay Regulators, vii, 148-50 Relays, in telegraph lines, iv, 293-4, vii, 110, 374 Relief Features, making and leveling of, xiv, 80; of new and old areas, iii, 33, 34, 34-5, xiv, 47-9; of sea bottom, iii, 52, xiv, 286-7; orders of magnitude, 27 Relief Models, vertical exaggeration of, xiv, 9-10 Religion, Religions, Babylonian and Assyrian influences, xvi, 51-2; beginnings and development of, xv, 326-59, xvi, 44; development of, at cattle-raising stage, xv, 199; fear and, 185; fire in, 234; marriage and, 291, 292-3; meanings of, 326; medicine and, x, 12, 16, 34, 242-3; morality and, xv, 355-7, xvi, 43-4, 45, 48; psychological factors, xi, 130, 151, 204; science and, iv, 27-8, xvi, 42, 44-5; similarities in, 43; universality of instinct, 43, 47 Religious Fanatics, exaltation of, xi, 120; hysteria of, x, 360 Religious Words, from Hebrew, xv, 161 Remedies, quack, vii, 240-1, x, 76, 367; specific, 49-50, 75 Remembering, process of, xi, 209 (see Memory) Remington Typewriter, v, 313, 381 Remora, dorsal fin of, xii, 133; used in catching turtles, 139-40 Remote Control, vi, 99-101; by radio waves, vii, 283-4; in power plants, vi, 360 Renaissance, medicine of, x, 43-60; science in, iv, 28, ii, 11-12, 12-13, 42 Rennin, enzyme, ix, 235 Repetition, psychological effects, xi, 21-2; in advertising, 348; in learning, 214-15 Repletion, sensation of, ix, 91 Repression, of ideas, x, 355-6, 361, 364, 365 (see also Suppression) Reproach, sentiment of, xi, 149 Reproduction (organic), x, 228; cells in, ix, 43, 324-5, 332-3, xv, 54, xvi, 156, 157-8; germ cells in, x, 232; in primitive animals, xii, 26, 31, 34, 53-4, 60; rapidity of, in plants and animals, xv, 19-21 Reproduction of Plants, xiii, 43-6, 48-53, 116-67; transitional form, 309, 316; without mating, 165-7, 182-3, 215, 217-18 Reproductive Instinct, xi, 56 Reproductive Tissues, cell development in, ix, 48, 287 Reptiles, xii, 182-238; age of, iii, 20, 21, 286, 292-3, xv, 71; birds and, iii, 295, 296, xii, 239; classification place, iii, 260; egg-laying of, xv, 275; evolution of, iii, 283, 285-6; first appearance, xv, 71; mammals and, xii, 271; Mesozoic, iii, 286-95, xii, 183, 188, 194-5, 202-3; origin of, 168; temperature variations, i, 317; tracks preserved in rocks, iii, 16 Repugnance, emotional, xi, 275 Repulsion, instinct of, xi, 55 (see also Disgust) Réseau, i, 221, 380 Réseau Mondial, i, 220, 380 Reservoirs, puddled-clay bottoms, xiv, 137 Residual Magnetism and Voltage, vi, 191, vii, 372 Residual Soils, iii, 26-8, xiv, 68, 145 Residue (chemical), viii, 381 Resignation, as intellectualized reproach, xi, 149 Resinous Electricity, iv, 258, vi, 12 Resins, electrical conductivity, iv, 259; electrification of, 257 Resistance, electrical, iv, 281-3, vi, 74-9, vii, 374-5; in dynamo armatures, vi, 185-6; in electric cells, 135-7; in electric wires, 79-80; in magnetic circuit, 93-4; in wireless circuits, vii, 286, 287, 290, 296, 297, 298; of various wires, vi, 77, vii, 378-80, 384; Ohmic, vii, 373; reduced by liquid air, i, 32; unit (see Ohms); variations with temperature, iv, 301 Resistance, Heat, vii, 337 Resistance (mechanical), relation to force, iv, 11, 90, 92 Resistance Coils, vii, 364 Resistance Furnaces, vii, 303-4 Resolution, and will, xi, 259-60 Resolution of Forces, iv, 76-7 Resonance, iv, 225-6; in sound, 226-32; in wireless currents, vii, 267, 289-90 Resorcinol, viii, 238 Respiration, chemistry of, viii, 36, 49-50; discovery of physiology of, x, 29, 88-9; of fishes, xii, 135; of insects, 103; of chelonian reptiles, 187; processes and disorders of, x, 338-42 (see also Breathing) Respiration Calorimeter, viii, 361, 367 Respiratory Center, ix, 257; control of, 264-5, 266 Respiratory Diseases, susceptibility to, xv, 51 Respiratory Quotient, x, 270 Respiratory System, laughter by, xi, 355, 356-7 Rest, as cure for fatigue, x, 247-8; efficiency and, xi, 363; necessity of, time used in, ix, 80; need of, in all things, xi, 21; nervous fatigue and, ix, 137-8 (see also Relaxation) Resting Arrow Argument, xvi, 85 Resting Metabolism (see Basic Metabolism) Resultant, of forces, iv, 76, 99 Retail Sales, and weather, i, 264 Retaliation, Law of, xv, 371 Retina, of eye, iv, 346-7, ix, 109, 110 (fig.), xi, 30, 62, 84, 89-97; color perception by, ix, 116-17 Retrospect, time lengths in, xi, 194 Retting Process, xiii, 239, 241-2, 243 Revenge, sentiment of, xi, 150 Reverberatory Furnace, v, 316-17 Reverdin, thyroid studies, x, 349 Reverence, sentiment of, xi, 147-8 Reversed Faults, xiv, 114 Revival of Learning (see Renaissance) Revolution of Earth, ii, 43; known to Aristarchus, 28; orbit, changes in eccentricity, 73, 74-5; orbit, measurement, 121, 162, 263; orbit, speed in, 91-2, 163; proved by aberration orbits of stars, 92; year measured by, iv, 15 Revolutionary War, Bushnell's submarine, v, 197; muskets in, 361; surgeons of, x, 104 Revolutions, geological, xiv, 29 Revolving Turret, patented by Timby, v, 380 Rex Begonia, reproduction, xiii, 165-6 Reymond, Emil du Bois, x, 126-7 Reynolds, Osborne, xvi, 132 Rhazes, Arab writer, x, 32 Rheas, xii, 243, 249 Rheostat, iv, 383, vii, 375; invention, vi, 23 Rheticus, friend of Copernicus, ii, 43 Rheumatism, Rheumatic Fever, x, 223-4; acute, ix, 187-8; barometric effects, i, 329; germ of, x, 195, 221, 223; leaking heart valves from, ix, 207; lightning cures, i, 153; salicylates in, x, 381; uric acid and, 343 Rhine River, changes in course and connections, xiv, 185-6; channel of, 87 (map), 117, 167; falls at Schaffhausen, 132-3; varied course, 155 Rhine Valley, xiv, 87 (map), 90, 117, 185-6; wine industries of, viii, 249 Rhinoceros, xii, 304-6; ancient remains, iii, 16, 303; formerly in Europe, xv, 76, 79, 92; Merck's, 100 (fig.), xii, 305 (fig.), 306 Rhizoids, xiii, 156, 157, 158 Rhodes, ancient importance, xiv, 281-2 Rhodesia, climate of, xiv, 224 Rhodium, viii, 173; symbol and atomic weight, 383 Rhododendrons, difficulty of obtaining, xiii, 289; in heath family, 202; in southern forests, 367; seed, 344 Rhodora, flower, xiii, 202 Rhubarb, origin, xiii, 223; oxalic acid in, viii, 222 Rhynchocephalia, xii, 183 Rhythm, idea of, in man, xv, 251, 310; In human organism, xi, 281; in learning, 214; in scientific progress, xvi, 46, 116 Ria Coasts, xiv, 257-8 Rib Cage, ix, 63, 65 (fig.) Ribs, of body, ix, 63 (fig.), 65; connections with breastbone, ix, 71 Rice, ancestral home, xiii, 182, 221; calories in, ix, 299; eating of, in relation to stature, xiii, 172; food value, viii, 364; fruit for seed dispersal, xiii, 54; history and uses, xiii, 213-14; importance, 10, 211; in grass family, 179; origin, xiv, 382; starch from, viii, 243; transplanting, in Java (illus.), xiii, 208; vitamines, in hulls of, viii, 369, ix, 35-6, x, 258, 259, 260 Rice Paper, source, xiii, 214 Richer, astronomer, ii, 59, 69 Richet, anaphylaxis studies, x, 212-13 Richter, J. B., chemical work, xvi, 160 Rickets, x, 264-5, 314 Rifles, xv, 218-19; improvements in, v, 362, 379; machine gun types, 366-8; standardization, 50 Rift Valleys, xiv, 117-21, 123 Rigg's Disease, x, 315-16 Right, original meaning, xi, 190 Right Ascension, ii, 299, 300, 305 Right-Hand Rule, vi, 55, 89-90 Rights, grasping instinct and, xi, 44 Rime, i, 108, 380; formation, 121-2 Ringhals, xii, 227 Ring Hypothesis (see Nebular Hypothesis) Ring Spinning Machine, v, 273, 276, 378 Ring Structure (molecules), viii, 233, 240, 381 Rio de Janeiro, Corcovado peak, xiv, 112; harbor of, 268 Rio Negro, connections of, xiv, 187 Rises, ocean, xiv, 286, 288, 290 Ritchey, astronomer, ii, 107-8, 148, 333, 336 River Beds, tunneling through, v, 121-4 River Man, iii, 302 Rivers, alterations in courses (historical), xiv, 183-6; ancient veneration of, v, 75; annual discharge of, xiv, 135; antecedent, 164-70; base-level of, 40, 49; "beheaded," 182; channels, gorges, and valleys, iii, 40-4, xiv, 49-52, 167-8; classification of, 153-5; connection of systems, 186-7; consequent, 157; courses changed by earthquakes, xiv, 335; courses determined by rock structure, 43-4, 131-2, 160, 175, 187-8; deltas (see Deltas); development of, 155-88; erosive work of, iii, 30-44, xiv, 39-40, 49-54, 158-63, 198, 233; forest regulation of, xiii, 372, xiv, 379; harbors in mouths, 270-1; headward extension, iii, 38-9, xiv, 175-6; homogeneous and heterogeneous, 154-5; importance, xv, 129; importance, by what determined, xiv, 189; importance, historical and industrial, 31, 190-7; in clayey country, 137; in new and old areas, iii, 33-4, xiv, 48, 49, 155-63; in regions of subsidence, iii, 37, xiv, 40, 163-4; in rejuvenated regions, iii, 36, 232-3, xiv, 40, 163, 164-70; longitudinal and transverse, 153-4; marine and continental, 153; metaphorical names of parts, xv, 158; mineral matter in, viii, 196, xiv, 206; obsequent, 160; "piracy," 177-83, iii, 38-9; potholes in beds, 39-40; power of currents, 30-1, xiv, 39-40, 198; power utilization, 5, 75-93; recession of spring heads, xiv, 176; sedimentary deposits of, xv, 84; sediment carried by, iii, 31-3, xiv, 52-3, 161; seed dispersal by, xiii, 346; sewage systems, viii, 325; sources of water, xiv, 182-3; subsequent, 159; superimposed, iii, 39, 137, 233-4, xiv, 170-4; topography produced by, 49-54; trunk and branch, 153; underground, iii, 116, xiv, 149-50; use in industry, vi, 352, 353, 361, 366-7; water supply from, xiv, 140, 141 (see also Drainage Systems) River Terraces, formation of, xv, 84 River Traffic, past and future, xiv, 31, 190-1 River Valleys, civilization in relation to, xv, 122, 128, 129; development, xiv, 49-52; general character, 56-7; in old and new regions, iii, 33-5, 36-7, xiv, 48, 49, 57; in stratified rock, 80-1, 82-3; soils of, 70, 71, 218; tributaries, 57; usually excavated by their streams, 123-4 Riveters, pneumatic, iv, 129, v, 129 Roads, good, and farmers, vii, 230-1; motor traffic and, v, 214-15; rough and smooth, in relation to traffic, 206-7 Roaring Forties, i, 128, 380 Robert, Nicholas Louis, v, 291, 377 Roberts, astronomer, ii, 135-6, 361 Roberval, xvi, 104, 114 Robins, westward spread of, xii, 53 Robinson Cup Anemometer, i, 83 Roche, astronomer, ii, 157, 380 Rochelle Salts, from baking powder, viii, 136 Rochester, N. Y., drumlins near, xiv, 60 Roches Moutonnées, xiv, 56 Rock, Rocks, iii, 382, xiv, 17; ages, how determined, iii, 17-19; blasting of, v, 100, 261; blocks and joints in, xiv, 128-30; carbon dioxide absorbed by, viii, 49; chemistry of, 192-5; classes, iii, 12-13, xiv, 17-19; coloring, iii, 25-6, 44; color changes, viii, 194; composition, 192-3; disintegration, chemical, and physical, viii, 194-5, 338 (see Weathering of Rocks); erosion of (see Erosion); formations, iii, 379; fracturing and folding (see Faults, Folding); geology the study of, iii, 9, 12; geological history, 164-248; ground water effects on, xiv, 141; in interior earth, iii, 108, 110; joints, 23, xiv, 128-9; land forms determined by, 43-4, 80-113, 125-7; metal-bearing, iii, 355-70; non-metalliferous, 370-6; oldest, 160, 163, 168-9; permeability of, xiv, 137; plucking of, iii, 29; primary and secondary, viii, 191-2; rotten and bed, iii, 26, xiv, 64; specific gravity, 11; stream adjustment to, 160, 175; striation, iii, 63, xiv, 56; structure, defined, iii, 383; structural changes, 83-98; subsurface exploration, v, 262-3; undermining or sapping of, xiv, 131; weathering of (see Weathering) Rockaway Beach, iii, 58 Rock Basins, iii, 142-3, xiv, 202-3 Rock Crystal, iii, 337 Rock Debris, as deep sea deposit, iii, 55; carried by ice, 68; carried by winds, 73 Rock Drills (see Drills) Rockefeller Foundation, International Health Board of, x, 171-6 Rocket Lightning, i, 149, 152 Rockets, in aerology, i, 22-3 Rock Flour, xiv, 69 Rock Gypsum, iii, 331, 375-6 Rocking Stones, iii, 70 Rock Pigeon, xii, 265 Rock Rabbits, xii, 304 Rock Salt, iii, 374-5, xiv, 209 Rock Saws, ancient, xvi, 67 Rock Slides, earthquakes and, xiv, 333-4 Rocky Hill Sill, xiv, 109, 111 Rocky Mountain Forest, xiv, 373-4 Rocky Mountain Revolution, iii, 218, 219; dinosaurs destroyed by, 298 Rocky Mountains, age of, iii, 191, xiv, 235; birth of, iii, 218-19; coal areas, 348; forming agencies, 230; fossils found in, 263; geological strata, 138, 177, 184; glaciers of, 240, xiv, 54-5; granite-cored, 111, 228; lakes in, iii, 143; mineral wealth of, xiv, 237; plateau west of, 220, 380; red beds, iii, 208; rejuvenation in Tertiary time, 231; rock weathering in, xiv, 76; sea over, iii, 130, 181, 184, 195, 197, 213; thrust faulting in, 90; volcanic activity, 229 Rodents, xii, 285-96 Rods, of eye, xi, 84, 89-90, 96 Rods, vibration of, iv, 213-15, 223-4 Roemer, discovery of speed of light, ii, 50-60, 91; transit instrument, 58 Roentgen, Prof., vii, 249; X-ray discovery, iv, 55, 317, x, 184, xvi, 192-3 Roentgenography, x, 185-6, 373 Rogers, Samuel Baldwin, xvi, 174 Rohlfs, explorer, i, 210 Rokitansky, Carl, x, 113 Roller-bearings, v, 205-6 Roller Mills, introduction, v, 381 Rollers, friction-saving by, v, 204-5, 205-6; not found in nature, 16, 215 Rolling Country, iii, 34 Rolling Friction, v, 203-4, 207, 214-15 Romance Languages, descent from Latin, xv, 160 Romanche Deep, xiv, 289 Roman Empire, Alps Mts. and, xiv, 240; growth and fall, 307; metal supplies, 237; medicine under, x, 25-31; survey of, xvi, 98 Roman History, Alps Mountains in, xv, 137-8 Roman Numerals, xv, 183 Romans, character and civilization, xvi, 97-8; divisions of day, v, 57; elephants of, xii, 302; gods of, xv, 344; knowledge of loadstone, vi, 28; plants known to, xiii, 215, 216, 253; superstitions of, xv, 355; taste and smell, cultivation by, ix, 98 Roman Soldiers, javelins of, xv, 213 Rome, civilization of, xv, 122; copyists and books of, xv, 178-9; fire veneration in, 234; lampreys in ancient, xii, 130-1; policy with conquered peoples, xv, 155-6; sleeping sickness in, x, 301 Römer, Ole, thermometer of, i, 69 Rondeleti's Shark, xii, 145 Rood, O. N., i, 146 Roofing, copper, viii, 163 Rooms, appearance of filled and empty, xi, 187; ventilation of, ix, 268, 269 Room Temperature, iv, 137 (fig.) Roonhuyze, Hendrik, x, 80 Roosevelt, Theodore, African trip, xvi, 16; on rain forests, xiii, 365; on the caribe, xii, 159 Root, C. J., wheat studies, i, 253 Rootcap, xiii, 17-18 Root Hairs, xiii, 17, 91-4 Rootless Plants, xiii, 15 Roots of Plants, xiii, 15-22; downward growth, 84-6; functions, 15-22, 61, 80, 91-4; galls, 98; nitrogen absorption, 98; of scavenger and parasitic plants, 99, 100; sugar storage in, ix, 27-8 Rootstalks, xiii, 22-3; potatoes as, 24 (fig.); reproduction from, 43, 182-3, 215, 217-18 Ropes, materials of, xiii, 10, 239, 240, 241 Rosales, antiquity, xiii, 324-5 Rose Apples, origin, xiii, 226 Rose Beetles, and magnolias, xiii, 130-1 Rose Bugs, xii, 124 Rose Family, xiii, 197-8 Rosemary, source, xiii, 205 Rosenau, quoted, i, 328, 329 Rose of Sharon, xiii, 200 Rose Quartz, silica in, viii, 90 Roses, generic and specific names, xiii, 170-1; leaf arrangement, 37, 38; petal arrangement, 190 Rose's Fusible Metal, iv, 162 Rosetta Stone, xv, 172 Ross, Sir Ronald, x, 156-7; article on, 155 note Ross Antarctic Expedition, xvi, 142 Rosse, Lord, discovery of spiral nebulæ, ii, 361, 372, 380; Leviathan reflector, 16-17, 105-6 Rossignol, Jules, i, 348 Rotary Converters, vi, 342-8, vii, 199, 365 Rotary Engines, v, 148 Rotary Press, v, 301, 305-6, 378, 379 Rotation, iv, 85-6; energy of, 83-5; magnetism of, ii, 178; researches in dynamics of, 166-7 Rotation of Crops, viii, 342-6 Rotation of Earth, ii, 43; ancient Greek beliefs, 28, 36, xvi, 81; changing speed, ii, 74, 375, 376, 377; De Cusa on, xvi, 102; deflection of moving bodies by, i, 124-5, xiv, 32, 303, 348, 351; effect on earth's shape, ii, 69; effect on gyroscope, iv, 255; effect on weights, ii, 69, iv, 74-5; measure of day, 15-16; precession in relation to, ii, 71; proved by aberration orbits of stars, 92; rising of sun due to, xvi, 12 "Rotten" Plants, xiii, 99-100 Rotten Rock, iii, 26, xiv, 64 Rotterdam, Holland, xiv, 271 Roughness, sensation of, xi, 128 Roundheads, racial division, xvi, 49 Roundworm, x, 200 Rousseau, philosophy of, xvi, 111, 117 Routine, in relation to will, xi, 261 Roux, antitoxin work of, x, 396; pupil of Pasteur, 143 Roving, cotton, v, 272-3 Rowland, Prof. Henry A., heat work of, iv, 49-50; on atoms, viii, 187 Rowntree, categories of therapy, x, 380; kidney test, 378; on therapeutic science, 334 Royal Families, origin of, xv, 366 Royal Society of England, xvi, 111-12; Duchess of Newcastle's visit to, iv, 53 Rozier, M. de, v, 220-1 Rubber, artificial, viii, 257; chemistry and manufacture of, 257-8; electrification of, iv, 257, 259; economic importance, xiii, 11, 208; history and production, 245-9; source of, xiv, 383 Rubbers, wearing of, x, 306 Rubber Trees, xiii, 245, 247-8 Rubidium, viii, 128, 132, 133; spectrum of, 302; symbol and atomic weight, 383 Rubies, variety of corundum, iii, 327 Ruby Glass, viii, 282 Rudolphine Tables, ii, 44, 216 Rulers, origin of, xv, 263-7 Rum, making of, viii, 250 Rumford, Count, heat theory of, iv, 47-8; on friction and heat, xvi, 125, 131 Ruminants, xii, 311-12 Rumor, autosuggestion in, xi, 304 Runge, chemist, xvi, 163 Runners, in transportation, v, 214-15 Running, as exercise, x, 304; reflex processes in, ix, 155-6 Rusby, H. H., on Amazon region, xiii, 360 Rush, Benjamin, x, 104 Rushes, ancient, iii, 254; origin and products, xiii, 244 Russell, giant and dwarf star theory, ii, 150-1, 153, 309, 310, 382, 384; photographic work, 130; studies of binaries, 326, 328, 329 Russia, agricultural meteorology, i, 249-50; beet sugar production, xiii, 216; bison of, xii, 329; elk in, 318; forests and grasslands, xiv, 380-1; gold production, iii, 365; harbors closed by ice, xiv, 267; loess deposits, 72; meteorological service, i, 223, 228; Napoleon's invasion, 306-7; oil output, iii, 350, 354; plains of, xiv, 217; rainfall of, 355; rodents of, xii, 294; sleeping habit of peasants, xi, 285; steppes (see Steppes); wheat cultivation, xiii, 211; winters in, xiv, 347; "Young Women's Summer", i, 362 Russian Alphabet, xv, 176 Russian Language, xv, 162 Rust, of wheat, xiii, 13, 71 Rusting, of iron, iii, 25, viii, 9, 10, 155-6 Rutabaga, xiii, 19, 223 Ruthenium, viii, 173; symbol and atomic weight, 383; valence of, 178, 180 Rutherford, chemical work, xvi, 120, 177 Rye, food value, viii, 364; native of Old World, xiii, 182; phosphate requirements, xiv, 67 Sabbath, among early Jews, x, 15 Sables, xii, 350 Sacandaga River, iii, 245 Saccharide, viii, 381 Saccharose, viii, 226-7, 242-3 (see Cane Sugar) Sacrifices, religious, xv, 347-8, 354, 358-9 Sacrum, ix, 64 (fig.), 66 Saddle (meteorology), i, 238, 380 Safety Devices, vii, 32-3 "Safety First," vii, 33, 355, xi, 365 Safety Matches, viii, 88 Safety Valve, earliest use of, iv, 171 Saffron, origin, xiii, 255 Sagebrush, xiv, 380 Sagitta, xii, 18 Sago, source of, viii, 243 Sago Palm, xiii, 309 Sahara Desert, antelopes of, xii, 327; depressions of, xiv, 205; dust from, i, 55, iii, 54; harmattan, i, 134; impenetrability of, xv, 136; largest desert, xiii, 377; rain and snow in, i, 210; sand storms, iii, 73 Sailing, against wind, iv, 77 (fig.), v, 182, 186-8 Sailing Vessels, historical development, v, 75, 111, 182, 188-9; relative decline of, i, 37 Sails, evolution of, xv, 265 St. Anthony Falls, xiv, 171; rate of recession, iii, 246 St. Cæsarius, i, 132 St. Elias Range, volcanoes of, xiv, 315; youthfulness of, 96, 235 St. Elmo's Fire, i, 157-8, 380; as ignis fatuus, 347 St. Gothard Tunnel, xiv, 240, 241; heat encountered in, iii, 121 Saint Helena, groundsel of, xiii,345; volcanic origin, xiv, 277, 289, 316 St. Helens, Mount, xiv, 315 St. John, astronomer, ii, 82, 154 Saint John's Bread, xiii, 226 Saint Lawrence, Gulf of, iii, 235; Bird Rock of, xii, 253; lows (cyclones) in relation to, i, 137 St. Lawrence River, discovery of, xiv, 310; historical importance, 191; white whales of, xii, 297 St. Lawrence Valley, geological history, iii, 78, 195, 232, 234, 235 St. Louis, early growth, xiv, 219; power supply from Keokuk, v, 83; water supply, viii, 326 St. Malo, Gulf of, tidal system, v, 176 St. Martin, Alexis, ix, 240, x, 121 St. Martin's Summer, i, 362, 381 St. Mihiel Salient, xiv, 91 St. Patrick, legend of, xii, 217 St. Pierre, destruction, iii, 103, xiv, 325 St. Vincent, eruption of La Soufrière, xiv, 28 Saint Vitus, x, 360 St. Vitus Dance, rheumatism and, 224 (see also Cholera) Saké, Japanese, xiii, 213 Sakhalin, separation from Asia, xiv, 274 Salads, food value of, x, 273 Salamanders, xii, 169, 170-3, iii; ancient, 285; evolution of, xii, 167, 168; regeneration in, 170; sense organs in, 169 Sal Ammoniac, solution of, temperature produced, iv, 136, 175 Sal Ammoniac Cell, iv, 297, 298 (fig.), vi, 59 Salerno University, x, 36-7, 38, 77, xvi, 100 Salesmanship, psychology of, xi, 334-42 Saliceto, surgeon, x, 38-9 Salicylates, in rheumatism, x, 381 Salicylic Acid, viii, 236, 239, 372 Saline Lakes, xiv, 206-9, 212 Salisbury, Prof., relief classification, xiv, 27 Saliva, conveyance to digestive canal, ix, 189-90; in digestion, viii, 358, ix, 227-30, 235-6, x, 319; of infants, ix, 346; secretion of by chewing, 163; thirst relief by, 89 Salivary Glands, blood supply of, ix, 197; fear effects on, 166, 221, xi, 132; reflex control of, ix, 163, 165; response to tastes, xi, 74, 76 Salmon, xii, 154, 156-8; canned, calories in, ix, 299; eggs, number of, xv, 20; instinct of, xi, 46; river habits of, ix, 174-5; shooting of, xv, 227 Salpae, xii, 19-20, 129 Salsify, origin, xiii, 223 Sal Soda, viii, 135 Salt, Common (see Common Salt) Salt Lake City, site of, xiv, 208 Salt Lakes, viii, 139; persistency of, xiv, 199 Salt Pork, calories in, ix, 299 Salton Sink, iii, 156, xiv, 204-5 Salts, defined, viii, 381; digestion of, 356; electrolytes, 125; esters, 221; formation and nature, 114, 115-18; formers (halogens), 84; in body fluids, ix, 174, 175-6; in blood, filtered by kidneys, 272, 273; in fabrics, viii, 256; in sea and inland waters, 138-9, 195-7, xiv, 295-7; in sea, gradual accumulation, ix, 175-6; ionization in solution, viii, 119-25, 300-1; most important, 130; natural deposits, 138, 195-7, 275; nomenclature, 98; organic life in relation to, ix, 174-6; positive and negative elements, viii, 126; protoplasm dependence on, ix, 32, 174; uses, viii, 146 Salvador, Izalco volcano, xiv, 321; public health fellowships, x, 172 Salversan, x, 381 Salvia, corolla, xiii, 201; flower, 48, 204, 205; petal arrangement, 190 Samara, winged fruit, xiii, 58 Samarium, atomic weight and symbol, viii, 383 Samoan Islands, native prayers, xv, 345-6 Sampson Cell, vi, 138, 144 Samson, Hebrew sun-god, ii, 20 Sanctorious, Santoro, x, 70-1 Sand, corrasion by, iii, 72, xiv, 77; form of rock, 18; rock formed from, iii, 13 (see Sandstone); wind-carrying of, 71, 72 73, 74-5 Sand Bars, iii, 57, 58; effect on waves, v, 124 Sand Blast, iv, 129-30, v, 135-6; natural, xiv, 77 Sand Cherries, origin, xiii, 226 Sand Dunes, iii, 71; migration, 74; vegetation xiii, 149 Sand Filters, viii, 319-20 Sand Hogs, v, 117 Sand Hoppers, xii, 82, 85 San Diego, Cal., North Island station, i, 48 Sand Myrtle, petals, xiii, 202 Sandpaper garnet, iii, 330 Sandpipers, xii, 262 Sand Saucers, xii, 73 Sandstone, iii, 13, 382, xiv, 18; bad conductor of heat, 12; frost destruction of, 77; jointing in, 133; occurrence, iii, 372; permeability, xiv, 137; quartzite from, iii, 169, 189; weathering of, 25, 27 Sandstone Belt, of eastern U. S., xiv, 107, 111-12 Sandy Hook, iii, 58 Sandy Regions, sledges used, v, 214-15 Sanford, F., on ignis fatuus, i, 249 San Francisco, bubonic plague in, x, 164; harbor of, xiv, 268-9; latitude and climate, 345; power supply, vi, 363 "San Francisco," wreck of the, i, 272 San Francisco Bay, xiv, 257-8, 268-9 San Francisco Earthquake, iii, 94-7; cause of, xiv, 128, 340; experience with building types, 343; faulting at time of, iii, 89; lateral displacements in, xiv, 335; origin of fault, iii, 224 San Francisco Mountains, xiv, 102 Sanguine Temperament, xi, 153, 159, 205 Sanitary Chemistry, viii, 317-33 Sanitary Sewage, viii, 324 Santa Maria Eruption, xiv, 314, 325-6, 328-9; earthquakes preceding, 338 Santo Domingo, sugar cultivation, xiii, 215 Santorin, volcano, xiv, 317, 319 Santorin Islands, xiv, 319 Santos-Dumont, v, 227-8, 382 Sao Paulo University, Brazil, x, 172 Sap of Plants, xiii, 80, 81; distribution, 23, 24, 25-6; functions, ix, 27 Saplings, in temperate forests, xiii, 369 Sapodilla, origin, xiii, 225, 226 Saponification, viii, 221, 381 Sapote, origin, xiii, 226 Sapper, on Santa Maria eruption, xiv, 328 Sapphires, iii, 327; electrification, vi, 12 Sapping, of rocks, xiv, 131 Saprophytes, xiii, 99-100; in heath family, 202; orchids as, 185 Sapwood, xiii, 24, 25, 26, 177 Sarasin, P. & F., i, 58 Saratoga Springs, carbon dioxide in waters, xiii, 49; known to Indians, xiv, 145; seaweed reefs near, iii 251; stream changes around, 243-4 Sarawak, war play of natives, xv, 307-8 Sardinian Rise, xiv, 291 Sargasso Sea, xiii, 73; ianthina of, xii, 19; temperature of waters, 21 Sargon the First, writings of, ii, 19-20 Saros, Chaldean, ii, 27, 209-10, 215 Särs, naturalist, xvi, 148 Sarsaparilla, source, xiii, 188, 255 Sassafras Family, xiii, 196-7 Sassafras Tree, antiquity of species, xiii, 324-5; distribution, 351; earliest appearance, 318; northern limits, 367; stamens and pistils, 120 Satellites, in solar system, ii, 163; habitability, 249-50, 262; of various planets, 241, 249-50, 261-4, 268; of moon, 208; orbits of, 197; theories of origin, 370, 371, 374, 380; weighing of primaries by, 75-6 Satin Spar, iii, 331, 332 Saturated Air, i, 14, viii, 67 Saturated Color, xi, 90 Saturated Vapor, iv, 167-8, v, 140; temperature table, iv, 173 Saturation, chemical, viii, 206, 230-1 Saturn (planet), ii, 264-6; comet families, 271; "great inequality," 87; life on, 249; photographic study, 133; rings, 133, 264-6; rings, discovery, 54, 96, 109; rings, Cassini on, 59; rings, Huygens on, 54, 57; rings, Keeler on, 120-1; rings, Laplacian theory, 370, 372; rotation period, 377; satellites, 249-50, 264; satellites, discovery, 85, 104, 146; size and orbit, 162, 163; weight, 77 Saurians, xii, 182, 203 Sauropods, iii, 288-9 Savages, æsthetic arts of, xv, 296; attitude toward nature, 329; body mutilations among, 257-60; brain in, 63-4; canoe-making, 262; child-bearing among, 278; clothing of, 252, 254, 255; cooking methods, 283; counting ability, ii, 9, xv, 180; dances of, 305-6, 310-12; dramatic art of, 303-10, 322; feet of, 61; fire sources and generation, 230-1; fire worship, 234; fish-catching methods, xv, 227; grouping tendency, 363; hair decorations, 260-1; hunting methods, 222-3; hunting stage of present, 187, 192-6; keenness of senses in, 228; leaders and rulers, xv, 363-6; life of, remarks on, 9-10; marriage among, 278-82, 283-5; marriage ceremonies, 292; musical scales of, iv, 206; music of, xv, 312-15, 316, 318; natural selection among, 47; obedience to customs and laws, 374-5; painting of body, 255-6; poetry of, 319-21; poison uses by, 227-8; polygamy among, 287; rain-makers, i, 334; religious ideas, xv, 234, 292, 304-6, 326-59, 375, 380; salt esteemed by, ix, 95; sex relations among, xv, 277-8; similarity to ourselves, 9; songs of, 319-21; time divisions, v, 57; tribal morality of, xv, 374; war dances, 307; writing a mystery to, 164 "Savannah", steamship, v, 192-3, 378 Savannah River, shad time in, xii, 155 Savory, source, xiii, 205 Sawfish, xii, 148-9; teeth of, 134 Sawflies, xii, 125 Saws, chisel form, v, 46; electric, on farms, vii, 229; gang, xi, 268 Saxon Chronicle, eclipse recorded in, ii, 210 Scale, musical, iv, 206-9 (see Musical Scale) Scale Insects xii, 112 Scales, of fishes, xii, 134-5 Scallops, xii, 59, 60, 65 Scandinavia, coasts concordant, xiv, 249; early seamanship in, 261-2; lakes of, 200; level changes in, iii, 80, xiv, 33-4, 35-6; rock formations, iii, 172, 178 Scandinavian Languages, xv, 162 Scandinavians, in Nordic group, xvi, 48 Scandium, discovery of, viii, 180; symbol and atomic weight, 383 Scaphopoda, xii, 58, 74 Scarabs, xii, 123 Scarf Clouds, i, 104, 381 Scarlet Fever, effects on ear drum, ix, 103; immunity to, x, 207; virus of, 141 Scarpa, surgeon, x, 104 Scarring, of body, xv, 257-8 Scars, xi, 248; formation of, ix, 48, 287; treatment of disfiguring, x, 189 Scar Tissue, ix, 348 Scepters, xv, 207-8 Schadenfreude, xi, 351 Scheele, Carl Wilhelm, xvi, 120-1, 177 Schiaparelli, studies on Mars, ii, 229, 235, 237 Schiff, thyroid studies, x, 350 Schiffli Machines, v, 286, 287 Schiller, skull capacity, xv, 40 Schist, iii, 169, 189, 382; jointing of, xiv, 133; metamorphic rock, 19 Schizogony, x, 158 Schizopoda, xii, 19 Schleiden, Matthias, x, 119, 120, xvi, 142 Schleswig-Holstein, föhrden of, xiv, 259 Schlick, Dr., v, 342, 384 Schmidt, Dr. William, i, 193 Schneefresser, i, 133 Schoharie Creek, xiv, 179 Scholastic Philosophy, xvi, 99, 100 Schönbein, xvi, 163 Schönlein, Johann Lucas, x, 113 Schools, seats and desks in, ix, 56-7; teaching of hygiene in, x, 283-4; ventilation, ix, 97 Schuchert, quoted, iii, 205, 278, 293, 297 Schultze, Max, x, 131; on protoplasm, xvi, 166 Schuster, astronomer, ii, 178, 224 Schwann, Theodor, x, 119, xvi, 142 Schweitzer's Reagent, viii, 256 Science, Airy on progress of, ii, 82; Aristotle on, xvi, 88; art and, iv, 9; birth of true, ii, 9-10, 86; exact and complex, x, 368; field of, xvi, 35; history of, xvi, 39-198; imagination in, xvi, 58-9; importance and interest, xvi, 9-34; industry and, v, 15; invention and, iv, 44-5; "laws" of, iv, 19; meaning of, vi, 10, xvi, 39-40; measures and units in, iv, 45-6; methods of, 26, vi, 10, xvi, 10, 34-5; philosophy and, 112, 115; principles of, remarks on, iv, 9-10; progress, means and ways, xvi, 30, 41, 46, 75, 76, 98, 116, 118; realm of, vi, 107; religion and, iv, 27-8, xvi, 42, 44-5; St. Augustine on, 99; specializing axiom, x, 43; understanding of, xvi, 10-11, 30-4; unity, 34, 35 Sciences, abstract and concrete, xvi, 42; development of, iv, 9-11; historical sequence, xvi, 35; interrelations and boundaries, 35, 42; summarized, 36-8 Scientific Expeditions, xvi, 123, 140, 142 Scientific Laws, iv, 19, vi, 106; principle of final common path in, xi, 23 Scientific Research, in World War, v, 360 Scientific Tendency, growth of, vi, 330 Scientists, methods of, xvi, 10, 11, 41; realm and aim of, vi, 107 Scoresby, Capt. William, i, 173, 361 Scoriæ, of volcanoes, xiv, 323 Scorn, facial expression of, xi, 133; sentiment of, 148 Scorpion Flies, xii, 106 Scorpions, xii, 89-90; ancient, iii, 278 Scotch Fir, in Danish peat bogs, xv, 87 Scotch Mist, i, 108, 377 Scotland, bag-pipes of, xv, 317; corries of, xiv, 58; fjord coasts, 258, 259; former volcanoes, 318; Gulf Stream effects, 304; Highlands, conquest of, 243; Highlands, geology of, iii, 172, 178, xiv, 122-3, 272; lakes of, 200; latitude of, 345; lava plateau, 103-4; lowlands, 123; scurvy and potato crop, x, 266; shoals on west coast, xiv, 47; wave pressure on coasts, 300; wild deer of, xii, 317 Scott, explorer, death of, x, 252 Scott, Prof. W. B., author PHYSIOGRAPHY, Vol. xiv; quoted, iii, 17, 18, xii, 332 Screens, shadows of, doubled, iv, 332-3 Screw, v, 37-9; Archimedes, iv, 26, 27 (fig.); form of inclined plane, 90; friction with, 93; gimlet-pointed, v, 379; mechanical advantage of, iv, 91-2 Screw and Cogged Wheel, iv, 92, 93 (fig.) Screw Pines, xiii, 187, 354 Scribes, ancient and modern, xv, 177 (fig.), 178 Scrub Vegetation, xiv, 378-9 Scud, cloud form, i, 101, 381 Scully, William C., on snakes, xii, 214-15, 227-8, 231-2 Sculpture, beginnings and development of, xv, 108-9, 111 (fig.), 117-20, 300-2 Schultetus, surgeon, x, 78 Scum, of pools, xiii, 13, 73 Scurvy, x, 264, 265-6; vitamines to prevent, 261, 262, 263 Scythes, development, v, 240-1 Sea, animal life in (see Marine Animals); geological work of, iii, 51-8; man's invasion of the, v, 182-202 (see also Ocean) Sea Anemones, xii, 23, 37-8 Sea Bathing, x, 312 Sea Birds, xii, 251-4; feathers of, 244 Sea Breezes, i, 131, 381 Seacoasts, civilization in relation to, xv, 128, 129 (see Coasts) Sea Cucumbers, xii, 50 Sea Devils, xii, 150 Sea Elephant, xii, 335 Sea Fans, xii, 37, 43 Sea Fleas, xii, 85 Sea Grapes, xii, 75 Sea Hares, xii, 68 Sea Horses, xii, 163 Sea Island Cotton, v, 269, 270, xiii, 236-7 Sea Level, changes in, iii, 83 Sea Lilies, iii, 259, 268-70, xii, 48-9 Sealing Wax, electrification of, iv, 257-8, 258-9 Sea Lions, xii, 333-4 Seals, xii, 333-4, 335 Seamanship, developed in Scandinavia, xiv, 261-2 Sea Mosses, iii, 259, 270 Sea of Darkness, legend, i, 55 Sea Mouse, xii, 54 Sea Necklaces, xii, 73 Sea Pens, xii, 43 Sea Purses, xii, 148 Searchlights, iv, 352 Searchlight Shells, v, 372 Sears, astronomer, ii, 153, 298 Searles Lake, potash supplies, viii, 279 Sears Roebuck & Company, small power sets, vii, 232 Sea Scorpions, iii, 260, 278 Sea Serpents, ancient, iii, 288 Sea Serpent Stories, origin of, xii, 80, 143 Sea Shells, xii, 71-4 Sea Sickness, cause, xi, 127; James on phenomena of, x, 242 Sea Slugs, xii, 68 Sea Snakes, xii, 225, 229 Seasons, phenology, i, 254, 255 Sea Swallows, xii, 264 Sea Turtles, xii, 192-3; catching of, 139-40 Seatworm, x, 200 Sea Urchins, iii, 259, 269 (fig.), 270, xii, 50 Sea Walls, of Galveston, xiv, 303; wave action on, 301-2 Sea Water, atmospheric carbon absorbed by, i, 14; density of, iv, 149; effect on seed, xiii, 346; gold in, viii, 197, xiv, 295; organic life in relation to, viii, 355, ix, 174, 175; radioactive matter in, i, 143; salts and other dissolved substances, iii, 51-2, viii, 139, 140, 279, xiv, 295-7; salts in, gradual accumulation, ix, 175-6 Seaweeds, classification, iii, 251; flowerless plants, xiii, 13, 43; great Pacific, 27, 66-7; habits and character, 72-3; iodine in ash, viii, 197; potash from, 279, xiv, 67, 68; Pre-Cambrian, xiii, 304; remains in old strata, iii, 20, 250, 251, 252, 256; reproduction, xiii, 166 Sea Wrack, fertilization, xiii, 151-2 Sebaceous Glands, ix, 313-14, x, 310 Sebum, x, 310 Secchi, Fra Angelo, ii, 17, 114, 115 Secchi Classification (stars) ii, 115-16, 118 Second, unit of time, iv, 70 Secondary, Cyclonic, i, 238, 381 Secondary Cells, iv, 383, vii, 363 (see Storage Batteries) Secondary Coils, iv, 383; of transformers, vi, 308 Secondary Currents, vii; in induction coils, vii, 243 Secondary Rock (see Sedimentary Rock) Secondary Spectrum, ii, 101, 108 Secretin, x, 325 Secretion, Borelli on, x, 72; metabolism of, ix, 159 Secular, meaning in astronomy, ii, 74 Secular Parallax, ii, 316-17 Sedentary Habits, food requirements with, ix, 297; sluggishness from, 223, 251 Sedges, xiii, 187-8; family, 179, 180; fertilization, 148; first appearance, 319; product and origin, 244; stems, 182 (fig.) Sedimentary Rocks, iii, 13, 382, viii, 191, xiv, 18; folding of, iii, 85, xiv, 32, 36 (see Folding of Rock); fossils in, iii, 16-17; jointing of, xiv, 130; land forms in, 44, 80-99; marine, 19-20; oldest, iii, 163, 165, 167; original horizontal formation, xiv, 36; weathering of, 79 (see also Strata) See, on binaries, ii, 377 Seed of Plants, xiii, 59-62; absent in some plants, 13, 14, 215, 218; of annuals, 53; destruction of, xv, 21; dispersal methods, xiii, 55-9, 338-48; dispersal by sea currents, xii, 42; fats from, viii, 246; germination (see Germination of Seed); naked and enclosed, xiii, 174-5, 178; number and increase, xv, 19; persistence of life in, ix, 16-17; small-sized, xiii, 344; storage of food in, 96, ix, 27-8, 278; survival of, by what determined, xv, 22, 23, 25; waste of, xiii, 11-12 Seed-bearing Plants, iii, 251 Seed Ferns, iii, 251, 254-5 Seed-habit, beginning of, xiii, 309, 310 Seeding Machines, v, 244 Seed Leaves, xiii, 60-1 (see Cotyledons) Seedless Plants, xiii, 13, 14 (see also Cryptogams) Seedlings, destruction of, xv, 21 Seeing Machines, v, 331-2, 334-5 Seihun River, xiv, 185 Seine River, tidal basin, v, 176; trench of, xiv, 89 Seismographs, iii, 93 Seismology, xiv, 337 Selection, artificial, ix, 327, xvi, 154-5, 157-8; natural (see Natural Selection) Selenite, iii, 331 Selenium, sensitiveness to light, v, 332, 334; symbol and atomic weight, viii, 383 Seleucus, astronomer, ii, 28 Self, "real," x, 302 (see also Personality) Self-abasement, xi, 55; in admiration, 147 Self-assertion, xi, 56, 146 Self-Control, xi, 257 Self-encouragement, xi, 278; in salesmanship, 336-40 Self-excited Dynamos, vi, 187, 191 Self-Feeling, in various sentiments, xi, 146-50 Self-Fertilization of Plants, xiii, 120; avoidance of, 152-3; Darwin on, 135; preventive methods, 120-2, 123, 127-30, 131, 134, 135, 141-2; as last resort, 135-44 Self-Gratification, impulse of, xv, 185 Self-induction, vii, 375 Self-interest, not the motive of crowds, xi, 330-1 Self-luminous Objects, ix, 105-6 Self-Maintenance, impulse of, xv, 185, 186-204, 273 Self-Perpetuation, impulse of, xv, 185, 273 Self-preservation, emotions of, ix, 153, 165-6, 171-2; instinct of, x, 9-10, 282-3, xv, 273 Selfridge, Admiral, periscope, v, 200 Self-Sacrifice in plants, xiii, 52-3, 61-2, 117, 151 Self-Starters vi, 238-9, vii, 120, 127, 142-3 Selkirk Mountains, snow mushrooms, i, 116 Semaphores, i, 282 Semicircular Canals, ix, 89-90, 101 (Fig.), x, 126; in fishes, xii, 137 Semites, rule of fathers among, xv, 367 Semitic Languages, xv, 161-3 Semitic Religion, sun-worship in, ii, 20 Semmelweis, x, 114, 115, 122, 144; debt of women to, x, 149 Seneca, on comets, ii, 85 Seneca Lake, xiv, 203; delta in, 211 Senecio, seed dispersal, xiii, 345 Sensation, xi, 62-4; defined, 67-8; dependent on motor response, 43, 66, 74-5, 102-3, 110-11, 118-21, 123-4, 202-3; dependent on sense organs, x, 118; hallucinatory, 358; nervous impulse from, xi, 19; perceptions and, 160-1; physical effects, 67-8; physical essentials and cost, 25; threshold of, 71 (see also Senses) Sense Organs, at birth, ix, 349-51; cell structure of, 22; classes, 86; condition in attention xi, 228-9; connections with brain, ix, 142-4, 145-6; connections with dendrites, xi, 19; connections with muscles, ix, 19-20, 122, 124-37, 139, 140; development in embryo, xi, 35; in amphibians xii, 169; in fishes, 137-9; of skin, ix, 314; part of, in maintaining life, 19, 21, 23, 166-7; percentage of error, xi, 184-5; receptive attunements, 62; sensations dependent on, x, 118; threshold of sensation, xi, 71; summation of stimulations, 21-2 Sense Perception, motions of, ix, 82 Senses, contact, ix, 86, 91-5; distance, 86, 96-121; hypnosis of, xi, 315; internal, ix, 86, 87-91; number and kinds, xi, 63-4, 109; primary purpose of, ix, 86-7 "Sensible Temperature," i, 318, 381 Sensitive Plant, xiii, 113-14 Sensory Nerve Cells, ix, 125, 126 (fig.); at birth, 348; connections of, 129-31, 142 Sensory Neurones, xi, 21; development in embryo, 34, 35 Sensory Reaction Type, xi, 155, 156-7, 158, 159 Sentiments, xi, 143-51; in advertising, 345-6 Sepals, xiii, 45, 47 Separately-excited Dynamos, vi, 187, 191 Separate Origin Theory, xv, 69 Separation, energy of, iv, 82 Separators, electromagnetic, vi, 103-4 Sepia, origin of, xii, 79 September Massacres, honesty of crowds, xi, 331 Septicemia, x, 198 Septic Tanks, viii, 328 Sequoias, ancient and present, iii, 256; Californian, xiv, 374; climatic record in rings, i, 199-200, xiv, 362; former distribution, 375 Serbia, Austria's control of, xiv, 306; Turkish conquest, 243 Serbian Language, xv, 162 Series, chemical, viii, 381 Series Circuits, vii, 364, 375 Series Field of dynamos, vi, 189 Series Wound Motors, vi, 231-4 Serow, xii, 325 Serpentine, iii, 338 Serpents, xii, 211-38; descent of, 203; eggs, care of, xv, 275 Serpollet, flash boiler, v, 213 Serpula Tubes, xii, 55 Serums, used in diagnosis, x, 215-16; use of, in disease prevention, 218, 296-7, xv, 49 (see also Antitoxins) Serum Sickness, x, 212, 215 Serval, xii, 357 Servant Question, electricity and, vii, 74, 90 Sesheta star goddess, ii, 24 Seven, basic number, xvi, 80; former supposed virtue of, ix, 115 Seventeen-year Locusts, xii, 112, 113 Severinus, Marcus Aurelius, x, 79 Severn River, tidal basin, v, 177; tides of, xiv, 293 Seville, Giralda Observatory, xvi, 100 Sewage, composition, disposal, and purification, viii, 324-9; in water supply sources, 318, 319, xiv, 140-1; oyster and clam poisoning by, xii, 59; plant fertilizing by, viii, 327, 343-4 Sewer Gas, harmlessness, i, 326 Sewer Pipes, bamboo stems as, xiii, 183 Sewers, rainfall and, i, 110 Sewing Machines, v, 283, 284-5, 379; embroidering and lace-making, 285-8; motor-driven, vii, 84-5 Sex, determination of, ix, 338-40, xvi, 156; effectiveness of jokes on, xi, 355-6; hereditary traits, bound up with, ix, 338, 340-1; in flowers, xiii, 46-7; in various trees, 191-2; influence on disease, x, 237; of twins, ix, 44 Sex Chromosomes, ix, 339; hereditary traits carried in, 338, 340-1 Sex Determiners, ix, 338-9, x, 234, xvi, 156 Sex Glands, double functions of, x, 347 Sex Relations, among animals, xv, 274-7, 277-8; among primitive men, 277-8; varying ideas of morality in, 286 Sexual Feelings, xi, 63, 138, 139 Sexual Impulse in man and animals, xv, 273, 274; repression of, x, 356 Sexual Reproduction (see Reproduction) Sexual Selection, xv, 274 Seychelles Islands, coco-de-mer of, xiii, 60, 154 Shad, xii, 154-5; river habits of, ix, 174-5 Shadbush, leaves of, xiii, 105 Shaddock, origin, xiii, 226 Shadoof, v, 18-19 Shadows, iv, 332-4; colored, xi, 94-5; in distance perceptions, 183; in perception of solidity, ix, 120; savage fear of, xv, 330 Shaft-sinking, v, 260 Shagreen, xii, 134 Shakespeare, pronunciation changes since, xv, 156 Shale, iii, 13, 382; petroleum source, viii, 209-10; schist and gneiss from, iii, 169, 189; weathering of, 27 Shaler, Nathaniel, on lunar surface, ii, 376 Shallow Water Belt, xiv, 24-5 (see Continental Shelf) Shamash, sun-god, ii, 20 Shame, Carlyle on, x, 306; custom and, xv, 254-5 Shape, perception of, ix, 105 Shapers, metal cutting by, v, 47 Shapley, astronomer, ii, 17, 153, 326-7, 330, 337, 338, 339, 340, 356 Sharks, xii, 142-7; caudal fin in, 133; evolution, iii, 282, 284; eyes of, xii, 138; gill clefts in, 148; scales of, 134; sense of smell in, 139 Shark's Teeth, fossils of, xii, 142 Sharps, musical, iv, 208, ix, 100 Shasta Indians, arrows of, xv, 196 (fig.) Shasta, Mount, iii, 106, 226 Shat-el-Arab, xiv, 185 Shaw, Lieut., aeronaut, i, 285 Shaw, Sir Napier, i, 139-40 Shear, plane and torsional, iv, 158 Shearing Machines, motors used, vi, 234-5 Shearing of Sheep, pneumatic, v, 130 Shears, as levers, v, 23, 46 Shearwaters, xii, 252 Sheep, xii, 324, 326; anthrax of, Pasteur's work on, x, 140-2; domestication of, xv, 197; elastic cord in neck, ix, 59; horns of, xii, 325, 328 Sheep-cold, i, 363 Sheep-raising, in New Zealand and Australia, xiv, 384 Sheet Lightning, i, 148-9, vii, 205, 213 Sheet Tin, viii, 161 Sheldrakes, xii, 257 Shellac, composition and use, viii, 264 Shell-Animals, origin and development, iii, 20, 264, 265-6, 272, 273-5 Shellfish, xii, 57-80 Shells (animal), calcium carbonate in, viii, 152, 354; deposits, iii, 53, 54, 235, 257-8, 272; formation of, xvi, 145; rocks formed from, iii, 13, viii, 152 (see also Chert, Flint, Limestone) Shells (artillery), v, 371-2, 373; explosives for, viii, 260; triple reports in World War, i, 193 Shell Worms, xii, 54-5 Shelter, man's need of, ix, 308-9 Shenandoah River, longitudinal character, xiv, 154; piracy of, iii, 38-9 Shenandoah Valley, xiv, 167 Sherrington, Charles, x, 131; quoted, xi, 12 Shetland Islands, storm waves in, xiv, 300 Shields, xv, 221 Shields River, Montana, xiv, 176 Shields, Tunnel, v, 122-4 Shin, bones of, ix, 68, 70 (fig.) Shiners, xii, 161, 163 Shinleaf Plants, xiii, 99 Shipbuilding, developed in Scandinavia, xiv, 261 Ships, ancient and modern, xiv, 265; bottoms, how cleaned, ix, 174, 175; bow and stern shapes, v, 191-2; concrete, 194-5; gyroscopic stabilizing, 341-2; handling in cyclones, i, 277-8; Marconi distress system, vii, 284; materials of hulls, v, 194-5; measuring of position of, 65-6; refrigerating systems, 353; St. Elmo's Fire on, i, 157; speed and driving power, v, 190-2; strains, 194, 195; water and air resistance, 190-2; wireless directing, vii, 284, 285; why they float, v, 95 (see also Steamships, Steel Ships) Ships' Chronometers, v, 65-7 Shirt Tree, xv, 256 Shivering, heat production by, ix, 309-10 Shoals, xiv, 286; aerial mapping, i, 47; effect on waves, v, 124 Shoal Water Belt, xiv, 24-5, 46-7 (see Continental Shelf) Shock, cause and treatment of, ix, 195; kinetic theory, xi, 59; low blood pressure in, x, 336 Shoes, mending of, by electricity, iv, 10; proper and improper, ix, 69-70, x, 306; working, xi, 279 Sholes, typewriter, v, 312, 380 Shooting-Star Plant, xiii, 203 Shooting Stars, ii, 164, 283-9; altitude in air, i, 17 (see also Meteors, Meteorites) Shops, displays and weather, i, 266; electric wiring, vii, 57 Shore Lines (see Coasts) Shore-Weed, distribution, xiii, 352 Short-Circuits, defined, vii, 375; protection against, 35-50 Shortening Agents, viii, 232 Shorthand Typewriter, v, 313 Short Heads, skull index in, xv, 42 Shoulder Blades, ix, 63 (fig.), 66 Shoulder Girdle, ix, 66 Shoulder Joint, ix, 66; dislocation of, 71 Shovels, most efficient lifts, xi, 362 Showers, curious, i, 355-9, 55 Shrews, xii, 366, 367, 368 Shrimps, class of, xii, 81, 82; swimming of, ix, 39 Shrubs, garden, planting tables, xiii, 272-89; hairy covering, 104-5; in plant classifying, 175; older than herbs, 319; roots, 16 Shu, Egyptian god, xvi, 77 Shuman, Frank, solar engine, ii, 169; sun-power plant, v, 177-8 Shunt Circuits, vii, 364 Shunt-Wound Dynamos, vi, 187-8, 191-2 Shunt-Wound Motors, vi, 229-31, 232 Siam, opium in, xiii, 253; rivers of, xiv, 196; viper of, xii, 230 Siberia, animals of, xii, 317, 349, 350, 356; anti-cyclone of, i, 218; extinct animals, iii, 16; low temperatures, i, 209-10; plains and table lands of, xiv, 217; rift valleys in, 123; rivers of, 195 Sibert, Maj.-Gen'l William, x, 187 Sicily, earthquake belt of, xiv, 340; temporary island near, 319-20 Sickles, evolution, v, 240 Sickness (see Disease) Sidereal Period, of moon, ii, 196 Siderite, viii, 156 Siemens, Sir William, xvi, 175, 176 Sierra Chica Observatory, ii, 146 Sierra Nevada Mountains, age, iii, 191; canyons, 225; cirques, 66; exfoliation in, 24; fault scarp of, 89, 225, xiv, 117, 122, 230; fault valleys in, xiv, 127; filled lakes of, 212; former volcanic activity, iii, 226; geological history, 136, 140-1, 213-14; glaciers, past and present, xiv, 54-5; granite core, iii, 112, xiv, 111, 228; intense folding, 230; lakes, iii, 143; metamorphism in, xiv, 234; Mother Lode gold belt, iii, 366; power plants, v, 79, vi, 363; precipitation on opposite sides, xiv, 355; snowfall, i, 118-19 Sight (sense), iv, 346-7, ix, 104-21, xi, 83-97; acuteness of, vi, 272-3; arrival platform for, ix, 146; center of, xi, 97; defects of, 112-14; deficiency, to what due, iv, 322; development in infants, ix, 350, 351, xi, 40; direction perception by, ix, 118, 120; distance and depth perception by, 118-20; illusions of, iv, 323, 326-9; in fishes, xii, 138-9; nerve of, xi, 29-30; space perception by, 163, 169-70, 171-2, 173, 174-83; touch and, ix, 92; walking reflex from, ix, 158 Signal Fires, xv, 165-6 Signals, distress, wireless, vii, 284; storm, i, 282-8 Signal Service, weather service called, i, 216 Signal Systems, of railroads, vii, 355-9 Signatures, magazine sections, v, 306-7 Sign Languages, xv, 148-51 Sign Lighting, vi, 280, vii, 339-48; colors in, iv, 51; psychology of, xi, 344, 345, 346 Silence, from interferences of sound, iv, 218, 219, 220-2; horrors of world of, 51; zones of, i, 189-92, 381 Silica, viii, 90; in earth's crust, 193; in iron ore, iii, 356; in organic compounds, ii, 243; petrifying material, iii, 127; residue of primary rock, viii, 195 Silicates, identification, viii, 201; in earth's crust, 90, 193, 194, 198, 200-1; in glass making, 281; preparation of, 117; specific gravities, 202 Silicles, xiii, 197 Silicon, viii, 19, 90; atomic weight and symbol, 383; compounds, 90; in body tissues, 354; in earth's crust, iii, 308, viii, 19, 129, 192; in wireless detectors, vii, 269; metallic, 300-1; plant needs of, viii, 337, 341 Silicon Carbide, vii, 310 (see Carborundum) Silicon Dioxide, viii, 90 Silk, as clothing material, ix, 311-12, x, 308, 309; chemistry and manufacture, viii, 256; dyes for, 269; electrical conductivity, iv, 259; electrification of, 257, 258, 259; vegetable, viii, 255-6 Silkworm Moths, xii, 119 Silkworms, Pasteur's work on diseases of, x, 140 Sills (geological), xiv, 108-10; columns in, 130; illustration, 107 Sill Tunnel, corrasion in, iii, 29 Silurian Period, iii, 20, 191-4, 382; animals and plants of, 252, 268, 274, 278, 282, 284; limestones of, xii, 49; species of, xv, 71 Silver, iii, 338; affinity strength, viii, 128; atomic weight and symbol, 383; atomic weight determination, 308-9; contraction on solidifying, iv, 150; electrical conductivity, 283, vi, 80; electric positiveness, 59; extraction from ores, viii, 140, 170, 269, 270, 271-2; fusibility, 384; heat conductor, iv, 179; in heavy metal group, viii, 126-7; melting point and requirements, iv, 162; metallurgy of, xvi, 176; occurrence and uses, viii, 170-3, 198; "parting" from gold, 272; production, iii, 367-8; recovered in copper refining, vii, 319, 320, viii, 272; refining of, vii, 320; specific gravity, viii, 384; sterling, 171; tarnishing of, 13, 77; tests for, 286, 288 Silver Bromide, in photography, viii, 172 Silver Chloride, analysis, viii, 292; in photography, 173 Silver Compounds, in photography, viii, 171-3 Silver Nitrate, uses, viii, 72, 146, 290 Silver-Plating, vii, 318-19, viii, 284 Silver Suboxide, viii, 97 Silver Sulphide, viii, 13, 170-1 Silver Thaw, i, 108, 381 Similarity, association by, xi, 197 Simon, Gustav, x, 131 Simoons, i, 134, 381 Simple Mechanical Powers, iv, 25 Simplon Tunnel, heat encountered in building of, iii, 121, xiv, 14; length and altitude, 240, 241 Simpson, Dr. G. C., i, 93, 150 Simpson, Sir James, xvi, 185 Sims, Marion, x, 122, xvi, 186 Sin, disease as result of, x, 380 Sine Curves (electricity), vi, 201 Singers, range of, ix, 99; vocal cords of, 83 Singer Sewing Machine, v, 285 Singing, development of art of, xv, 296, 312-15, 325; of teakettle, iv, 167 Single-celled Animals, iii, 265 (see Unicellular Animals) Single-celled Plants, xiii, 166, 167 Single-fluid Theory, vi, 288-93 Single-Phase, defined, vi, 201-3 Single-Phase Currents, advantages and disadvantages, vii, 196 Single-Phase Induction Motors, vi, 241, 250 Single Rail Cars, v, 342-3 Single-thread Sewing Machines, v, 285 Sink Hole Lakes, iii, 157 Sink Holes, iii, 127 (fig.), 128 Siphon, atmospheric pressure in, i, 25; in ancient Egypt, xvi, 68 Siphonophores, xii, 37 Siren Whistle, iv, 205 Sirian Stars, ii, 115, 117; distance and brightness, 353; in galaxy, 122 Sirius, angular diameter, ii, 151; binary system, 334; brightness, 263, 295, 316; color, 115, 296, 297; companion of, 109; composition, 115; displacement in spectrum lines, 119; distance and parallax, 315, 319; distance increasing, 119-20; in moving cluster system, 343; magnitude, motion and type, 319; origin of name, 302 Sirocco Winds, i, 134, 381 Sisal, ropes from, xiii, 10; source of, 188, 240-1 Sitatungas, xii, 327 Sitka, climate of, xiv, 345 Sitka Spruce, in Pacific forests, 374 Sitting, right posture, importance of, ix, 57 (see also Sedentary Habits) Size, effect on attention, xi, 344; perception of, ix, 105; physiological actions dependent on, 296, 347 Skaptar Jokull, i, 59 Skaters (bugs), xii, 114 Skates (fish), eggs of, xii, 140; gill clefts in, 148 Skeletal Muscle, ix, 75-84; breathing controlled by, 256-7; contraction and relaxation, of, 164; nerve connections of, 160, 162; voluntary control of, 163 (see also Muscles) Skeleton, of vertebrates, xii, 132; weight of, iv, 13; compared with apes, xv, 59; bones of, ix, 59-71; cartilage beginnings, 58; connective tissue, 13, 71-2 Skeptics, Greek, xvi, 85 Skill, of artisans, past and present, v, 42, 46; fineness of discrimination in, xi, 125-6; origin in response processes, 45; will in relation to, 263-4 (see also Proficiency) Skim Milk, viii, 363 Skin, blood vessels of, how controlled, ix, 161, 163, 215, 216, 217; body heat regulation through, 310-12, 314-16; chilling of, effects, ix, 323; cold and warmth spots, 93; colors in different races and latitudes, xv, 36-7; cuticle of, ix, 312-13; development in black and white races, xv, 49-50; dry feeling, i, 322; effects of cold and wet on, x, 239; electric insulator, vii, 247; excretions of, ix, 314, x, 310-311; exercise effects on, 303; fear effects, xi, 131, 132; flushing and paling of, ix, 161, 162, 163, 165, 215; functions, 312-14, x, 310; germ infection through, 198, 201-2; growth of, ix, 47-8, 287, 312-13; hyperemia in sleep, xi, 284, 289; of Nordics and Iberians, xvi, 48, 49; oiling of, in hot and cold climates, x, 311; pain organs in, ix, 314; pores of, 322; protective structure, x, 201; sebaceous glands, ix, 313-14, x, 310; sense organs in, ix, 314 (see Contact senses); structure and sensations, xi, 109-15, 164-6, 184; sunlight effects, vii, 249; suppressed emotion effects xi, 141-2; temperature, i, 318; temperature sensations in, ix, 93-4, 319-20; touch sense of, 92 "Skin Friction," v, 191, 192 Skin Grafting, x, 183, 189 Skin Pain, xi, 117 Skins, as clothing, xv, 256, 257; canoes and rafts of, 264; use in ancient Egypt, xvi, 73 Skipping Silverfish, xii, 104 Skoda, Josef, x, 113, 115 Skolai Creek, Alaska, iii, 217 Skuas, xii, 264 Skull, Skulls, bones of, ix, 61-3; bones in infants, 345; measurement and classification of, xv, 42; of apes and men compared, 42-3, 62; of European races, xvi, 49, 50; of primitive men, xv, 91, 93; of various races, 41-3; use for drinking vessels, 248 Skullcap, flowers, xiii, 201, 205 Skull Capacity, xv, 40; in various men and races, 40-1; of apes and men, 89, iii, 302-3; of primitive man, 304, xv, 89, 94-5 Skull Index, xv, 42 Skunk Cabbage, xiii, 188, 350 Skunk, absence of fear, xi, 136; luminous species, i, 347; protective means, xv, 18, xii, 347, 348 Sky, colors, explanation, i, 164, 165-6; in art, 105; man's invasion of, v, 219-38; shadows of mountains in, i, 169-70 Skyscrapers, as lightning protection, vii, 219; in earthquakes, xiv, 343; wind-thrust on, v, 194 Slag, viii, 157-8; phosphate from, 280, 345 Slasher (weaving), v, 280 Slate, iii, 382; metamorphic rock, xiv, 19; origin and occurrence, iii, 372; quarries in N.Y., 189 Slaughterhouse Waste, as fertilizer, viii, 280, 343 Slavery, social results of, xv, 376, 378-9 Slavo-Lettic Tongues, xv, 162 Slavonian Language, xv, 162 Slavs, in Alpine group, xvi, 49; north and south, xv, 137 Sledges, in transportation, v, 214-15 Sleep, xi, 281-91; autosuggestion and, 306; causes and factors of, ix, 218-19; hot baths and, 322; heart rest in, 210; life during, ix, 11-12, 17; metabolism during, 282-3, x, 271; mind activity in, xvi, 19; nature and functions, xi, 281-91; periodic breathing in, x, 340; primitive conceptions of, xv, 328, 329, 332; retardation of impulses in, xi, 20; skin during, 110; tea and, xiii, 227; time spent in, ix, 80 Sleeping, of plants, xiii, 88-9, 113; outdoor, x, 240 Sleeping Sickness, immunity and susceptibility to, xv, 49, 50, 51 (see African, European Sleeping Sickness) Sleep-Walkers, xi, 286-7 Sleet, i, 107-8, 381; glaze called, 373; ice rain, 375 Sliding Elasticity, iv, 157-8 Sliding Friction, v, 203, 204, 207, 214-15 Slings, xv, 219-20 Slip Rings, of alternators, vi, 159, 177, 196-7 Slipher, astronomer, ii, 131, 147, 337, 363 Slivers, cotton, v, 272, 274 Slogans, effectiveness, xi, 332 Slot Machine, Hero's, xvi, 93 Sloths, xii, 282, 283 Slow Sand Filters, viii, 319-20 Slowworms, xii, 206 Slugs, xii, 69-70 Slums, infant mortality in, ix, 352 Smallpox, African superstition of, x, 285-6; consumption from, 292; early inoculation for, 100-1, 207; eruption on uncovered surfaces, 254; European epidemic of, 59-60; first described by Rhazes, 32; germ of, 200; immunity to, 207; prevention of, xv, 49; racial susceptibility to, 50, 51; vaccination discovery, x, 100-3, 207-8; vaccination success, 217 Smeaton, on Watt's engine, v, 44 Smell (Sense), ix, 96-8, xi, 69, 77-82; direction perception by, ix, 117, 120; distance perception by, 121; food-judging by, 95; in fishes, xii, 139; in insects, 101; in infants, ix, 350-1; nerve of, xi, 29-30; photisms of, 222; sense of, location, x, 341 Smellie, William, x, 104 Smelling, motions of, ix, 82-3 Smelting, v, 315-16, 317-18; dependent on oxygen, i, 24; history of processes, xvi, 174, 175, 176; precipitation treaters in, vii, 348-51; smoke from, 345, 346, 347 Smelts, xii, 154, 159 Smilax, leaves, xiii, 183 (fig.) Smilax Family, xiii, 188 Smiling, psychology of, xi, 357 Smith, Prof. J. Warren, i, 246, 248, 253 Smith, William, geological work, iii, 15, 18, xvi, 126, 168-9 Smith River, Montana, xiv, 176 Smithsonian Astrophysical Observatory, ii, 186 Smithsonian Institution, i, weather observations, i, 215-16 Smoke, cause and prevention, vii, 343-5, viii, 45-6; cloud and fog nucleus, i, 91, 94; electrical precipitation, vi, 164, vii, 216, 301-2, 343, 346-51; evils and war against, i, 63-5, viii, 304; from fires, in air, i, 56-7; from gunpowder, viii, 145; in air, clearing of, ix, 269; moor, i, 56; nuisance and waste, vii, 345-6 Smokeless Powder, viii, 145, 260-1; introduction, xvi, 163 Smoke Screens, phosphorus, viii, 87 Smoking, of foods, viii, 372 Smoking of Tobacco, xiii, 256; cancer from, x, 120; heartburn from, ix, 232 Smooth Muscle, ix, 74, 84-5; adrenalin effects on, 171; chemical control of, 167-9, 170, 336; emotional control, 163-7, 168; habit in operation of, 251; nerve connection and control, 159-69; occurrence in body, 160-2; reflex control, 163 Smoothness, sensation of, xi, 128 Smuggled Goods, X-ray search for, vii, 256-7 Smyth, Piazza, ii, 141 Snails, iii, 260, 272, 272-3, xii, 68-71; deep sea, 23; flower fertilizers, xiii, 123, 144, 153; in lakes, xiv, 211-12; winged, xii, 19 Snakebird, xii, 253 Snake Hill, N. J., xiv, 110 Snake River, xiv, 174-5; gorge of, xiv, 166 Snake River Valley, lavas of, iii, 228 Snakes, xii, 182, 211-38; absence of fear, xi, 136; ancient, iii, 295; ancient, xii, 210; egg-teeth of, xii, 205; embryological resemblance, xv, 54; in oceanic islands, xiv, 278; poison of, xv, 18 Snapdragon, flowers of, xiii, 190, 201 Sneers, origin, xi, 133 Sneezing, in infants, ix, 349; nervous mechanism, xi, 19, 20; reflex action, ix, 135, 258 Snell, Willebrord, ii, 58 Sniffing, effect of, xi, 80; purpose of, ix, 82-3, 96 Snipes, xii, 262-3 Snow, i, 114-17, 381; forests and, xiv, 378; freezing mixtures with, iv, 175; from cloudless sky, i, 119; glaciers and, iii, 59-60; railroad problem, i, 267; regelation of, iv, 166; removal problem, i, 117; water supply from, i, 118; winter wheat and, 253 Snow Bins, i, 118, 381 Snow Clouds, i, 101, 102 Snow Crystals, i, 115-16 Snowdrops, flowers, xiii, 120 Snow-eater Winds, i, 133, 369 Snowfall, glaciers in relation to, xiv, 54-5; heaviest in U. S., i, 118-19; measurement, 79-80, 118, xiv, 351 (see also Precipitation) Snowfall Charts, i, 206 Snowflakes, i, 115; clouds of, 92-3, 103; fogs of, 95 Snow Fleas, xii, 104 Snow Line, iii, 59; in tropics and arctic, xv, 72-3; on mountains, iv, 183-4 Snowstorms, St. Elmo's Fire in, i, 157, 158 Snow Surveys, i, 118, 382 Snubbing Posts, friction on ropes on, iv, 94 Soap, chemistry of, viii, 141-3, 221; hard water effects, viii, 143, 152, 322, xiv, 147; use of, in bathing, ix, 313, 314, x, 311 Soap Bubbles, iridescence of, xii, 245 Soap Films, colors of, iv, 377, xii, 245 Soapstone, iii, 339-40 Sobieski, John, xiv, 308-9 Sobrero, nitroglycerine, xvi, 163 Social Classes, rise of, xv, 375-8 Social Evolution, xv, 29-31 Social Institutions, crowd psychology in, xi, 333; development of, xv, 29-31, 383-4 Socialism, theories of, xv, 377-8 Social Workers, in treatment of disease, x, 383 Society, dominant impulses in, xv, 185; habit and stability of, xi, 255-6; language the product of, xv, 142 Sociology, concrete science, xvi, 42; least positive science, x, 368; medicine and, 369 Socrates, killed by hemlock, xiii, 250; on essential forms, xvi, 87 Soda, deposits of, viii, 275 Soda Ash, viii, 135 Soda Lakes, xiv, 206, 212 Soda Pulp, v, 294 Sodium, affinity intensity, viii, 128; affinity for chlorine, 120; alkali metal, 132; atomic weight and symbol, 383; electrolytic production, vii, 320-1, viii, 284; extraction by electrolysis, 271; flame color, 134, 301; fusibility, 384; in body tissues, 354; in earth's crust, iii, 308, viii, 19, 129, 148, 192, 195; metallic nature, 17, 127, 181; plant needs of, 337, 341; properties, 133-4; source of industrial, 275; specific gravity, 384; spectrum of, iv, 362, viii, 301; test for, 287, 289 Sodium Acetate, electrolysis of, viii, 266 Sodium Bicarbonate, viii, 136 Sodium Borate, viii, 141 (see Borax) Sodium Carbonate, viii, 116; manufacture of, 276-8; occurrence in nature, 189, 197; uses, 135, 146 Sodium Chloride, viii, 138-40; electrolysis of, 124-5; ionization in solution, 123, 301; in urine, x, 343; pure, xiv, 296; stability of, viii, 120 (see also Common Salt) Sodium Compounds, viii, 134-43; flame color, 301; in sea, 138, 196, 279; replacing potassium, 133-4, 144; uses, 146 Sodium Cyanide, viii, 141 Sodium Feldspar, viii, 90 Sodium Hydrogen Carbonate, viii, 135-6 Sodium Hydrogen Sulphate, viii, 83, 116, 137 Sodium Hydroxide, viii, 134-5; normal solution, 119; preparation of, 276, 278, 284; uses, 135, 141, 142, 221, 255 Sodium Hypochlorite, as antiseptic, x, 146, 181; preparation, viii, 284 Sodium Iodide, solubility, viii, 112 Sodium Light, colors in, iv, 365 Sodium Nitrate, viii, 137-8; Chilean deposits, 64, 72, 197, 280 Sodium Nitrite, viii, 141 Sodium Peroxide, viii, 134 Sodium Phosphate, viii, 89, 141 Sodium Silicate, viii, 141 Sodium Stearate, viii, 143, 221 Sodium Sulphate, viii, 83, 116, 137; electrolysis of, 125 Sodium Sulphite, viii, 117, 140, 146, 372 Sodium Thiosulphate, viii, 140-1, 172 Soffioni, steam jets, v, 179 Soft Coal, combustion, viii, 45; composition, 252; conversion into coke, 46, 252; distillation and products, 252-4; origin, xiii, 10 Soft Foods, for children, remarks on, x, 314, 315 Softness, sensation of, xi, 128 Soft Soap, making of, viii, 142 Soil, iii, 382; acid conditions and correction, viii, 346-7; air in, xiii, 92; alluvial, xiv, 70-1; bacteria in, xiii, 98; clay in, iii, 27-8, xiv, 137; conservation necessity, 64; constituents necessary to plants, viii, 341-6, xiv, 64-5, 66-8; depths of, iii, 26, xiv, 64; enrichment by nitrogen plants, xiii, 98; fertilization by lightning, i, 153; forest protection of, xiv, 379; formation and nature, iii, 26-8, 32 (illus.), viii, 191, 195, 338-41, 347, xiv, 63-4, 68-9; glacial, iii, 67, xiv, 69-70; holding of, by plant roots, xiii, 19; liming of, viii, 150, 346-7; loess (see Loess); of arid regions, xiii, 381, xiv, 68-9; rainfall effects on constituents, 69; residual, iii, 26-7, xiv, 68; restoration of, viii, 341-6, 347, xiv, 66-8, 69 (see also Fertilizers); sewage application to, viii, 327; traveled, xiv, 63, 69-75; vegetation determined by, xiii, 382, xiv, 363-4; volcanic, 69, 329 (see also Lava Soils); wind carrying of, i, 53-4, iii, 71, 73-4, xiv, 71-5 Soil Water, absorption by plants, xiii, 91-3; erosive depths, xvi, 173; plant materials in, ix, 26, 29; rise of, viii, 37 (see also Ground Water) Solar Apex, ii, 305 Solar Constant, iv, 194 Solar Day, iv, 16 Solar Eclipses, ii, 209-18; corona seen only in, 219; death of Domitian announced, 221; difficulty of observing, 219; Einstein theory tested by, 81-2; first accurate prediction, 27; necessary interval between, ii, 224; Hally's observations, 87; Hipparchus's discoveries, 32; prominences observed in, 179, 180; records of, in ancient China, 21-2; restricted areas, 207 Solar Engines, ii, 169-70 Solar Spectrum, ii, 111-12, 114, iv, 358-9, 362, 365-7; lines, how produced, ii, 184; photography, 128 Solar Stars, ii, 115; distance, 353; distribution, 122, 354; planetary systems, 252 Solar System, bodies and motions, ii, 162-4; brief description, iii, 158-9; identity with atomic, vi, 115; motions accounted for by Newton, ii, 67, 73; movement toward Hercules, xvi, 124-5; movement toward Lyra, ii, 122, 137, 305-6; position in universe, 353-4; sun as center (see Heliocentric System); theories of formation, 366-81, iii, 159-63; unit of measurements, ii, 315 Solar Tides, xiv, 292 Solder, tin and lead in, viii, 161-2, iv, 161-2 Soldering, alloys used for, iv, 161-2 Soldier Beetles, rains of larvæ, i, 356 Soldiers, asleep on march, xi, 286-7; crowd psychology in battle, 326-7; crossing of bridges by bodies of, iv, 225; fatigue relieved by music, x, 247; lack of choice in, xi, 260-1; sense of pain in, 119-20; shoes of, ix, 69 Solenoid, iv, 286-7, vii, 375 Solfatara, volcano, v, 180 Solidification, expansion on, iv, 149, 150-1, 163; heat of, 160, 161, 188; suspended, viii, 113, 304-5 Solidism, doctrine of, x, 25-6, 28 Solidity, perception of, ix, 119-20, xi, 173-83 Solids, chemical properties, viii, 297-301; distinguished by pressure, iv, 22-3; elasticity of, 156; expansion coefficient of, 145; heat conduction by, 176-7; heat effects on, 144, 152, viii, 25; melting of (see Melting); molecules in, iii, 309, iv, 22, 131, 152, 363, viii, 24; solutions in water, 112-13; sound velocity in, iv, 198; spectra of incandescent, ii, 112, iv, 360, 363; vibration of, 215 Solitaire (bird), xii, 269 Solomon, wives of, xv, 289 Solomon's Seal, rootstalk, xiii, 22 (fig.) Solstices, observed in ancient times, ii, 25-6 Solute, defined, viii, 382 Solutions, viii, 111; boiling point and freezing point, 299-30; chemical reactions in, 37; colloidal, 314-16; heat and cold production by, iv, 175; ionization of, viii, 119-25; molar, 118-19, 379; molecular action in, 113, 311; normal, 119, 379-80; of gases, liquids and solids in water, 111-13; osmotic pressure in, 113, 311, xvi, 164; overheated, viii, 304; properties of, summarized, 311-12; specific gravity of, 313; vapor pressure of, 305 Solutrian Implements, xv, 100, 105, 109 Solvay Process, viii, 276, 277-8 Solvent Action, of water, viii, 111-12; heat and, 112 Solvents, esters as, viii, 221; water, alcohol and ether, 217 Somaliland, antelopes of, xii, 327 Somme River, changes in, xiv, 184 Somnambulism, xi, 286-7 Song Birds, xii, 268-9 Songs, primitive, xv, 312-13, 314, 319-21 Sonic Wave Transmission, v, 108 Sonnblick, St. Elmo's Fire, i, 157, 158 Sonora Earthquake, xiv, 334 Soot, i, 52; deposits, 64, 65; formation of, viii, 45 Sophists, Greek, xvi, 87 Soranus of Ephesus, x, 26 Soreness, muscle, ix, 80-1 Sore Throat, cause, x, 253; from colds, 253; from infection of tonsils, ix, 187 Sorghum Molasses, viii, 243 Sori, of plants, xiii, 64, 155 Souder, Wilmer H., iv, 237 Soul, and body (Hindoo belief), ix, 11-12, 17; meaning of, xi, 382; primitive conceptions of, xv, 328-32; source of vital movement, (Stahl), x, 84; Thales on universal, xvi, 76; universal belief in, 44 Soule, Samuel W., v, 312 Sound, Sounds, analysis and synthesis of, iv, 52, 233-4; atmospheric effects, i, 187; audibility, distances and variations in, 187-92; audibility in rain, 187; audibility (vibration limits), iv, 204; colored hearing, xi, 222; dense atmosphere effects on, iv, 31-2; distance, how estimated, i, 187; emotions stirred by different kinds, iv, 51-2; intensity and loudness, 211-12; interference of, 218-22; kinds and qualities, xi, 104-8; motor response, 103; "musician" of physics, iv, 50; perception of, by ear, 203-4, 211-12, ix, 99, 100, 103; perception of direction and distances by, 117, 121, xi, 167-9; pitch of, (see Pitch); production, iv, 195-7, ix, 98; quality of, iv, 232-5; resonance, 226-32; shadows, 236; simple and compound, 213-17; transmission, i, 186, iv, 195-201, ix, 98-9; transmission by water, v, 107, 108; velocity, i, 186-7, iv, 198-9, 200, 201, vii, 210; wave theory of, iv, 52; wind effects on, 210-11 (see also Acoustics) Sounding Balloons, i, 20-1, 382; heights reached, 22 Soundings, ocean, xiv, 23-4, 284 Sound-ranging, i, 313; in World War, 201-2 Sound Waves, diffraction of, iv, 52, 236-7; Doppler's principle, ii, 119, iv, 209-10; effect on ear, ix, 99, 100, xi, 99-101; energy, on what dependent, iv, 211; formation and transmission, 196-201; frequency and length, 204, 236; from Krakatoa eruption, i, 188, xiv, 324; interferences of, iv, 218-19, vii, 279; interferences in thunder, i, 193; machine to respond to, v, 331; mechanical reproduction of, iv, 240; number, amplitude, and forms, xi, 104-5; passage through orifices, iv, 236; photographic records of, 52, 233-4, 237; power transmission by, v, 107-8; reflection and refraction of, iv, 236-40; simple and complex, 213-17; transmission, i, 186, iv, 196-201, ix, 98-9; visible, (flashing arcs) i, 194, 372 Soups, value of, at meals, ix, 241, x, 320 Sour, taste of, ix, 95, xi, 70, 71, 72 Sour Disposition, xi, 55 Souring, lactic acid in, viii, 223 Sourland Mountains, xiv, 111-12 Sour Milk, longevity and, xiii, 172 Soursops, origin, xiii, 226 South Africa, ancient reptiles of, xii, 184; animals of, 281, 304, 327-8, 345, 348, 360; bushmen of (see Bushmen); climate of, xiv, 224; cobras of, xii, 226, 227; diamond mines, iii, 328; duet whirlwinds, i, 60; glacial and coal deposits, iii, 203, 204; gold production, 365, 367; kopjes of, xiv, 82; no weather maps, i, 230; rodents of, xii, 289, 290; spurges, xiii, 28-9; stock-raising in, xiv, 384 South Aldabra, tortoise of, xii, 191 South America, animals (herbivora), xii, 275, 276, 282, 283-4, 289, 306, 313; animals (carnivora), 342, 360-2, 363, 364; antiquity of, 282; birds of, 241, 251, 256, 266; climate on east and west coasts, xiv, 305; coasts iii, 57, xiv, 25-6, 247-8, 250, 251; coasts, coral reefs on, xii, 40; coffee in, xiii, 232; drainage systems, xiv, 190; fish of, xii, 159-60, 166; former connection with Antarctica, xiv, 290; former submergence, iii, 216; indigenous plants, xiv, 382; meteorological backwardness, i, 218, 230; monkeys of, xii, 377; plains of, xiv, 218 (see also Pampas); plateaus of, 222; potato in, xiii, 218; reptiles, xii, 198, 208; river connections, xiv, 187; "scrub" vegetation of, 379; snakes of, xii, 213, 215-16, 221; temperate forests of, xiv, 371, 382; tobacco used by natives, xiii, 256; west coast harbors, xiv, 265 South American Indian, acclimatization of, xiv, 356; blow gun of, xv, 216, 217 (fig.); foot-plow of, 236 (fig.); long bow of, 213 (fig.); weapons of, 216, 219 South Atlantic Ocean, temperature of, xiv, 297 South Carolina, tin production, iii, 368 South Dakota, bad lands of, xiv, 81 (see Bad Lands); high temperature, i, 209; loess deposits, xiv, 72; "Sunshine State," i, 86; tin production, iii, 368 Southern Cross (stone), xv, 103 Southern Forest, (U. S.), xiv, 372-3 Southern Hemisphere, climates insular, xiv, 346; deflection of motion in, i, 125, xiv, 348; land in, 20; temperate forests of, 371, 382; tides in, 292; winds of, i, 125, 127-8, xiv, 345-6, 348 South Pole, rain at, (see also Antarctica) i, 109 South Sea Islanders, xv, 9; chiefs, how chosen, 364; ideas of morality, 254; plaited mats of, 243; writing venerated by, 164; words derived from, 161 South Sea Islands, atolls of, xii, 41; snakes absent from, 217 Sowerby, James, xvi, 170 Spa, Belgium, xiv, 145 Space, absolute and relative, ii, 80, iv, 16-17; æther of (see Æther); heat transmission through, iv, 180-4; infinity of, xi, 191, 196; interplanetary, air absent, i, 186; perception of, xi, 162-91; primary concept, iv, 14, 15; relativity of, xvi, 196-8; temperature of outer, vi, 270; time compared with, xi, 192 Spadix, of arums, xiii, 188 Spain, Arab astronomy in, ii, 38; buffaloes in, xii, 329; callina, i, 96; cattle of, xii, 330; coast formations, iii, 57, xiv, 46-7, 249, 257; conquests in America, 310; Cro-Magnons in, xv, 102; desiccation of, xiv, 379; esparto grass, v, 292; formerly peninsula of Africa, xiv, 291; lynx of, xii, 365; metal production, iii, 360, 362, 370, xiv, 237-8; Moorish science, xvi, 100, 106; potash deposits, xiv, 68, 209; Pyrenees Mts., as protection of, 239-40; rainfall of, 358; solar eclipses, ii, 215-16; toads of, xii, 176 Spallanzani, Lazaro, x, 88, 139, xv, 114 Spalling, of stones, iii, 24 Spanish-American War, searchlights at Santiago, iv, 352; typhoid fever in, x, 286; weather service in, i, 309 Spanish Armada, xiv, 280; weather importance, i, 307 Spanish Bayonet, xiii, 183 Spanish Fly, x, 111 Spanish Language, descent from Latin, xv, 160, 162 Spare Diet, remarks on, xi, 370 Spark Gaps, in wireless installations, vii, 263, 264, 271-2, 287 Sparking, of electric machines, 375; potential tables, 383 Sparrows, increase in U. S., xv, 21 Spathe, of arums, xiii, 188 Spawn, of mushrooms, xiii, 164 Speaking Trumpets, iv, 239-40 Spear-throwers, xv, 212 (fig.), 213 Spears, xv, 208-10 Specialization, in civilization, xv, 131-2, 203 Specializing, in science, x, 43 Species, xii, 28, xiii, 170, 329-30; chromosome numbers in different, ix, 46; climate effects, on, xvi, 141; continuity dependent on heredity, xiii, 326; crossing of (plants), 147; distribution studies, xvi, 140; establishment of new, 158; evolution of, iii, 18, 260-1; extinction of, 261 (6), 293, xiii, 323; geological epochs determined by iii, 19; number in relation to latitude, xiv, 366; number of plant, xiii, 323; origin, Darwinian theory, x, 135, xvi, 150-2 (see also Mutation, Variation, Natural Selection); permanence theory, xvi, 150; types and, xiii, 356 Specific, technical meaning, iv, 109, 383 Specific Density, iv, 111, 112, 113 Specific Diseases, x, 196 Specific Gravity, iv, 109, viii, 381; atomic weight and, 313; discovery by Archimedes, xvi, 89; methods of determining, iv, 111-13; mineral identification by, iii, 321-41, viii, 202-3, 313; of earth, xiv, 11; of metals (table), viii, 384; of solutions, 296, 813; of various substances, iv, 109-10 (see also Density) Specific Heat, iv, 109, 155-6, viii, 308-9, 382; of water, 37 Specific Nerve Energy, doctrine of, x, 118 Specifics, medicinal, x, 49-50, 75 Specter of Brocken, i, 184-5, 382 Spectral Types (stars), ii, 115-18, 307-10; absolute magnitudes and, 317; binary periods and, 310, 334; of star clusters, 343-4; of star streams, 347, 348; planetary systems and, 252; solar apex and, 305-6; speed of, 153 Spectrobolometer, ii, 128, 186 Spectrographs, at Mt. Wilson, ii, 154-5 Spectroheliograph, ii, 129, 183; in work on sun, 176, 179; of Mt. Wilson, 148, 154 Spectroscope, ii, 111, viii, 301; astronomical applications, ii, 17-18, 112-24, 181; chemical analysis by, viii, 301-2 Spectroscopic Binaries, ii, 122-4 Spectroscopic Parallaxes, ii, 153 Spectrum, Spectra, colors and lines of, ii, 111-12, 113, iv, 358-63, 365-7; displacement of lines, ii, 119, 120, 121; displacement of lines to test Einstein theory, 82; intensity of lines, 124; interceptions by atmospheric ozone, i, 16; of airlight, ii, 181; of aurora, i, 161; of alkali metals, viii, 133, 147, 301; of chemical elements, 183, 301-2; of nebulæ, ii, 357, 359; of new stars, 332-333; of stars, 115-18, 119, 123; of suns' corona, 211, 212, 223, 225; of sun-spots, 177; of vapors in magnetic field, 178; of variable stars, 325, 326, 329; used in measuring star distances, 153-4, 318; X-ray, viii, 183, 309 (see also Solar Spectrum) Spectrum Analysis, ii, 113-24, viii, 301-2; discovered by Kirchhoff, ii, 17 Spectrum Colors, eye receptors of, xi, 89-90 Speculum, defined, vi, 102 Speech, advantages over sign language, xv, 151-2; dense atmosphere effects on, iv, 32; emphasis importance in, xv, 144-5; evolution of, 152-4; physical factors of, ix, 83; power of, in man and animals, xv, 68, 91, 141 Speech Organs, tendency to respond to sound, xi, 103 Speed, perception of, xi, 165 (see Velocity) Speed Boats, vi, 192 Spelling, English, xv, 176-8 Spencer, Herbert, evolution taught by, x, 136; on education, 282, 284; on evolution, xvi, 152; on origin of priests, xv, 350; on relativity of knowledge, xvi, 195-6 Spermaceti, xii, 299 Spermatozoön, origin of energy, xvi, 145 Sperm Cells, production and development of, ix, 332-3, 335, 339 Sperm-Whale, xii, 298-9 Sperry, Elmer A., v, 343 Sphagnum Moss, xiii, 69, 160-3, 166 Sphalerite, iii, 339, 363, 364 Sphincter Muscles, ix, 85; fear effects on, xi, 132; of stomach, ix, 231, 232, 233, 234, 236-8; operation, xi, 37-9 Sphinx, erosion of, iii, 73 Spice Bush, xiii, 196, 351 Spices, xiii, 259-65; effects on stomach, ix, 243-4; food value, viii, 366; in preserving, 372; sensation from, ix, 98 Spiders, xii, 90-7 Spiegeleisen, v, 320 Spike, flower form, xiii, 50; of grasses, 181 Spinach, origin, xiii, 223-4 Spinal Column, ix, 64 (fig.), 65; in infants, xv, 81; in man and apes, 57-8; in vertebrates, 55-6; ligaments of, ix, 71; notochord of, xii, 128 Spinal Cord, ix, 131, 133 (fig.), xi, 25-7; inflammations, cause of, x, 224; medulla of xi, 28; nerve connections through, ix, 130 (fig.); neurones, xi, 21 Spinal Nerves, ix, 131-2, xi, 25-6 Spindles, ancient, xv, 244, 245 (fig.) Spine, tuberculosis of, x, 92 Spinning, by Lake Dwellers, v, 14; historical development of, xv, 243-4, 246 Spinning Jenny, invention, xv, 246 Spinning Machines, v, 273, 274-6, 376, 378 Spinning Wheels, v, 268, 273, 274; development of, xv, 244 Spinosa, philosophy of, xvi, 117 Spinosity, in animals, iii, 277 Spiral Gears, v, 38-9 Spiral Hypothesis (see Planetesimal Hypothesis) Spiral Nebulæ, ii, 361-5; discovery, 17, 106, 186, 380; distances, 124; distribution, 355, 356; globular clusters and, 337; Jeans on origin, 378; new stars in, 333; new universes, 381; origin, planetesimal theory, 372-4, iii, 160-2; star streaming and, ii, 348-9; studies at Mt. Wilson, 157-8; transition from nebula to star, 136 Spirilli (bacteria), x, 195 Spirits, savage belief in, xv, 331, 332, 337-40, 348-9, 350, 358 Spirits of Wine, viii, 213-14 Spirometer, x, 339 Spitball, effectiveness of, iv, 69 Spitting, indiscriminate, x, 291 Spitting Adders, xii, 227 Spitzbergen, coal deposits, i, 199; flora of, xiii, 341-2; ice-caps of, iii, 61 Splanchnic Nerve, xi, 273 Spleen, functions of, ix, 184, 275 Split-Phase Starters, vi, 250 Spoken Language, evolution of, xv, 152-4 Sponges, iii, 259, 266, xii, 23, 30-2 Spongin, xii, 31 Spontaneous Combustion, viii, 55-6 Spontaneous Generation, x, 139; history of doctrine, xvi, 114; origin of life by, xii, 10 Spoonbills, xii, 151, 256 Sporangia, xiii, 155 Spore-habit, relics in cycads and ginkgo tree, xiii, 309, 316 Spores, xiii, 64; dispersal by winds, 344; fermentation by, viii, 248; in atmosphere, i, 61; of anthrax bacillus, x, 149; of ferns, xiii, 155-7, 159, 160; of moss, 69, 162; of mushrooms, 163, 164 Sporogony, x, 159 Sports (mutants), ix, 342, xiii, 333-4 Sporulation, x, 155 Spotted Fever, cause of, xii, 98 Sprague, F. J., vi, 26 Spring, frosts, i, 257-8; rate of advance in U. S., i, 256 Spring Balance, iv, 58-9, 102 Springboks, xii, 327 Springhaas, xii, 289 Springs, iii, 116-17, xiv, 137-9; drying of, 136; fissure, 138, 152; fluctuations and constancy, 152; forests and, 379; Havana water supply from, 140; hillside, 137-8; in river formation, 175-6; in western canyons, iii, 116; "juvenile," xiv, 151-2; lacking in clay soils, 137; mineral matter in, viii, 195 (see also Hot Springs, Mineral springs) Springs (mechanics), air-cushioning of, v, 134; energy of, iv, 82, 87-8; pneumatic, v, 126; storage of energy in, 126 Spring-tails, xii, 104 Spring Tides, ii, 70, xiv, 292 Spruce, traveler, i, 352 Spruce Forests, xiii, 367-8; in relation to winds, 149 Spruce Trees, dominance in north, xiii, 350; in northern forests, xiv, 372, 374; nativity, xiii, 244; paper pulp from v, 292, 293, xiii, 10, 234, 244; planting conditions, 270; polycotyledons, 61; roots, 17 (see also Conifers) Sprudel Spring, xiv, 152 Spur Gears, v, 29 Spurges, antiquity, xiii, 324-5; South Africa, 355, 379; rubber from, 249; stems, 28-9, 30-1 Sputum, tuberculosis spread by, x, 291, 292, 293-4 Squalls, i, 382 Squash, origin, xiii, 224 Squaw Winter, i, 361, 382 Squids, xii, 79-80; deep sea, 23; phosphorescence of, 20; whales and, 299 Squirrel-cage Induction Motors, vi, 245; on farms, vii, 224 Squirrels, xii, 291-4; antiquity of, 286; arboreal habits, 285; man's lesson from, xv, 206; storing of fruits by, xiii, 56, 340; sugar, xii, 278 Stabilizers, gyroscopic, v, 341-2 Staffa, hexagonal columns of, xiv, 129, 130 Stags, xii, 317; age of, xv, 100 (fig.) Stahl, George Ernst, x, 84-5, 301 Stained-glass Windows, preparation of designs for, iv, 342 Stalactites and Stalagmites, iii, 127, viii, 151, xiv, 148; rate of formation, xv, 79-80 Stalks, of plants, xiii, 27 Stalling, of motors, v, 157 Stamens, xiii, 45, 46; arrangement in various flowers, 123-46, 181-207; in grasses, 182; of highly cultivated plants, 51; in reproduction, 117, 119, 120, 121, 122 Staminate Flowers, xiii, 46-7 Stamping, of feet, in excitement, xi, 356 Standard, of flowers, xiii, 47-8 Standard Barometer, iv, 119-23 Standardization, in manufactures, v, 48-52, 53-4, 55-6 Standing, correct posture in, ix, 57, x, 305; heart beat in, ix, 207 Stanley, Henry M., African trip, xiii, 359, 361 Staphylococci, x, 195 Star Anise, origin, xiii, 255 Star Apples, origin, xiii, 227 Starch, composition and properties, viii, 227-8; digestion of, 357, ix, 230, 235, 242, 292, x, 270, 326, 330; fermentation, viii, 225, 248, 249; food value, 365, ix, 300, x, 259, 262, 269, 271 (see also Carbohydrates); food amounts in ordinary diet, ix, 290, 300-1; foods for infants, 346; glucose production from, viii, 225, 228, 241, 243-4; iodine effects, 228, 294; made from rice, xiii, 213; making of, by plants, viii, 335, 349, ix, 27-8, 28-9, xiii, 79, 80, 83-4, xiv, 65; manufacture and uses, viii, 243; tastelessness of, 366 Star Charts and Catalogues, ii, 298-9, 300-3; early, 29, 31, 34, 39, 45, xvi, 90, (see also Draper Catalogue) Star Classification, by color, ii, 296-8; by giant and dwarf theory, 309; by magnitude, 295-6, 297; by spectra, 115-18, 307-10; by temperature changes, 309-10 Star Clouds, ii, 357-60 Star Clusters, ii, 122, 336-40; moving, 341-4; nebulæ and, 357; photography of, 136 Star Distances, ii, 311-18; ancient ideas, 28, 350; brightness in relation to, 322; first measurement, 16; methods of measuring, 124, 153, 311-13, 316-18; of Galaxy, 355; of globular clusters, 337, 338-9, 340; of nebulæ, 358; of spiral nebulæ, 363; of Sirians and Solars, 122, 353; unit of measurement, 315-16, xvi, 33-4 Star Distribution, ancient and modern conceptions, ii, 350, 352-3; Galaxy as basis, 350, 351, 352, 353, 354, 364-5; globular clusters, 338, 339 Starfishes, iii, 259, 268, 269, 270, xii, 49-50 Star Flowers, xiii, 203 Starling, Prof., quoted, xi, 154, 182; secretin discovery, x, 325 Stars, aberration orbits, ii, 90-1, 92; actual dimensions, 321-4; angular diameters, 150-1; brightness (see Magnitude of Stars); Classification (see Star Classification); constitution, 382-3; constitution determined by spectra, 17, 113, 114-18; distances (see Star Distances); distribution (see Star Distribution); evolution order, 116-17, 308-9, 310, 383; evolution seen in spiral nebulæ, 362; giant and dwarf, 153, 294, 309, 310, 382-4; light, 296, 16; light-intensity, vi, 272; light of, in space, iv, 334; magnetism, ii, 178; magnitudes (see Magnitude of Stars); motions (see Motus Peculiaris, Proper Motion, Star Streams); multiple, 335; naming of, 302-3; nearest, 319-20; nebulæ and, 308-9, 365, 381; nebulous, 360; new or temporary (see Novae); number, 294-5; origin, Jeans on, 378-9; parallax (see Parallax); photography in study of, 135, 137; planets of, 252-3; radiant energy, 384; radiative equilibrium, 383-4; right ascension and declination, 299, 305; spectral type, 115-18, 307-10; spectra affected by atmospheric ozone, i, 16; transit measurement by eye-and-ear method, xi, 155-6; twinkling, to what due, i, 174; universe of, ii, 294-9; variable (see Variable Stars); worship in ancient Egypt, 24; why unseen by day, i, 164 Star Streaming, ii, 306, 317, 345, 347; Jeans on origin, 378 Star Streams, ii, 345-9; nearest stars in, 320 Starters, automobile, vii, 120, 127, 135, 142-8; of motors, vi, 236-9, 250-5, 262-3 Starvation, x, 275; diabetes treatment by, ix, 294; sense of hunger in, 88; waste of tissues in, 297-8; weight reduction by, 302 Stassfurt Deposits, viii, 196, 278-9, 344, xiv, 67, 209 States of Aggregation, iv, 22 States of Matter (see Physical State) Static, technical meaning, iv, 383 Static, in wireless (see Strays) Static Breeze, vii, 238-9 Static Electricity, iv, 259, vi, 284-305, vii, 375; lightning as, 205, 206, 207-9 Static Generators, vii, 245 Static Induction Machine, vii, 236 Static Sense, xi, 126 Statics, defined, iv, 25, 383; early development of, 25, 27 Stationary Waves, iv, 217 Statue of Liberty, lighting, vi, 283 Statues, coloring of, xv, 300, 302; primitive, 118, 120 Stature, artificial selection, xvi, 154, 157; in relation to food, xiii, 172; of various European groups, xvi, 48, 49; of various races, xv, 38-9; rate of growth in man, ix, 32 (diagram) Steam, density of, iv, 113; dry and wet, v, 140; exhaust, vi, 355; invisibility of true, i, 90; latent heat of, iv, 188, v, 354, viii, 38; saturated and superheated, v, 140; saturated, pressure of, iv, 168; specific heat of, 155, 187; specific heat ratio, iv, 156; use in engine and turbine, v, 142 Steamboats, early, v, 189-90, 192, 377; early dangers, i, 49-50 Steam Boilers (see Boilers) Steam Carriages, v, 207-8, 212 Steam Electric Plants, vi, 351, 353-61; size of generating units, 378-9 Steam Engines, efficiency, on what dependent, iv, 192; estimate of work of, 193-4; history and principles, v, 139-48, 376; in power plants, vi, 354-5, 357-8; invention and consequences, xvi, 125, 126; origin in kitchen, v, 109; reciprocating compared with turbine, 152-4; starting of, vi, 235; temperature and pressures in, v, 139-40; waste of heat energy, 155; Watt's, 44, 47, 144-6, 376, 377 Steam Hammer, invention, xvi, 175; Nasmyth's, v, 379 Steam Heat, dryness of air from, xiv, 353 Steam Heating System, iv, 186-7, xiv, 353 Steam Navigation, development, v, 189-90, 192-4 Steam Power, disadvantages in mining, v, 128-9; from subterranean heat, 180-1; from sun's heat, 177-8; from volcanoes, 179-80; waste of heat energy, 155 Steam Reserve, of power plants, vi, 367 Steamships, development of ocean, v, 192-4, 378; glass-enclosed machinery, vi, 175; propellers (see Propellers); speed, power and lines, v, 191-2; turbines on, 105, 153 (see also Ocean Steamers) Steam Shovels, v, 252-3, 262 Steam Traction, beginnings, v, 207-8, 212 Steam Turbines, v, 148-54, 382, vi, 354-5; connection with ship propellers, v, 105-6, 153-4, vii, 329-30; efficiency, v, 155, 172; Hero's, xvi, 92, 93; most efficient speed, vii, 329; speed-limiting device, 49; use of steam in, v, 142 Stearic Acid, viii, 220, 221, 350 Stearin, glycerine from, viii, 247 Steatite, iii, 339 Stebbins, astronomer, ii, 212, 328 Steel, alloys of, xiv, 238; composition and properties, viii, 159-60; cutting of, vii, 321; elasticity of, iv, 36; expansion by heat, 145, v, 71; magnetism of, iv, 245, 251, vi, 36-8; purification in electric furnaces, vii, 304; structure of hard and soft, iv, 37; silicon in, viii, 90 (see also Steel Making) Steel Engravings, by electrotype, vii, 314 Steel Making, v, 319-25, 380, 383, viii, 159-60, 273, xvi, 174-5; electric furnace in, vii, 301, 305, 312; phosphorus obtained from, viii, 345 Steel Mills, electromagnets in, vi, 35, 86; great motors, 228-9; rise of body temperature in, ix, 317 Steel Rails, electric furnace steel for, vii, 312; expansion by heat, iv, 134; friction, v, 204, 206; manufacture, 322-3 Steel Shipments, meteorology in, i, 269 Steel Ships, v, 195; compass variations in, iv, 254, v, 340, vi, 42 Steel Structures, electrolytic corrosion, vi, 64-6; in earthquakes, xiv, 343 Steel Tracks, for trucks, v, 206-7 Steenheil, K. A., xvi, 191 Stegocephalia, xii, 168 Stegosaurs, iii, 289-90 Steinboks, xii, 326, 327 Steinmetz, C. P., vi, 26 Stejneger, Dr. Leonard, xii, 226, 234 Stems of Plants, xiii, 22-32; acting as leaves, 28-31, 378, 379; chlorophyll in, ix, 26; of grasses and sedges, xiii, 179, 182 (fig.), 183; purposes, 61; response to light, 85; roots from injured, 19; starch and sugar storage in, ix, 27-8; upheld by osmotic pressure, xiii, 94; violets without, 15 Stenotype, v, 313 Step-down Transformers, vi, 310 Step Faults, xiv, 116 Stephenson, George, locomotive, v, 208, 377, 378 Stephenson, Robert, link motion, v, 208-10, 379 Steppes of Russia, grasslands, xiii, 181, 373, xiv, 381; impossibility of forests, xiii, 349; wind-fertilized vegetation, 149 Step-up Transformers, vi, 309 Stereopticon, iv, 341-2 Stereoscope, xi, 177-81; depth impressions by, ix, 120; in lightning study, i, 148; in photographic map-making, i, 45-6 Stereoscopic Wind Maps, i, 230, 231, 233 Stereotyping, v, 302-3, 383 Sterilization, by heat, viii, 371-2; by ozone, vii, 354; by X-rays, 257 Sterilized Milk, vitamines in, x, 262 Sterling Silver, viii, 171 Sternoptychidæ, xii, 23 Sterols, viii, 350 Stethoscope, ix, 205; discovery and use of, x, 108-10, 112, 371 Stevens, Col. John, steamboat, v, 189 Stevenson-Huntington, on crocodiles, xii, 199-200 Stevin, Simon, xvi, 103-4, 109 Sthenic Disease, x, 89 Stichwort, in pink family, xiii, 195 Stinging Cells, xii, 33, 36 Stigma of Flowers, xiii, 46, 118, 119, 147 Stigmata, hypnotic production of, xi, 317 Stiles, Dr. Percy, on emotions, xi, 137-9; on hypnotism, 322; on nutrition and mentality, 369-70; on suppression of emotions, 140-1 Stiles, Prof., on malarial parasites, x, 159 Still Engine, v, 165-70 Stills, apparatus of, viii, 250 Stimuli, Stimulations, ix, 78; common response to varying, xi, 22-3; law of consciousness of, 27-8; law of summation, 21-2 Stipe, of mushrooms, xiii, 163 Stipules, xiii, 34, 35 (fig.) Stirling, Rev. Robert, xvi, 174 Stoats, xii, 349 Stock-raising, on grasslands, xiv, 383-4 Stocks (geological), xiv, 110 Stoics, definition of thought, xi, 228; fatalistic logic, 240; principle of reason, 228, 233-4; suppression of emotions, 140 Stokers, automatic, v, 211-12, vi, 354, viii, 46 Stokes, William, x, 112; ether theory, xvi, 137 Stoma, of leaves, xiii, 78, 82, 103, 109 Stomach, action of, ix, 230-8; action in hunger, ix, 88, 231, xi, 65-6, 123, 124; adjustment to meals, ix, 85; bacteria, few in, x, 201; brain and, xi, 370; condition between meals, ix, 230-1; control of action of, 163; disorders of, 238-41, x, 321-5; emotion effects on, ix, 165, 166, 241, xi, 135, 137; food absorption from, ix, 243-4; form and position, 233 (fig.), x, 321; functions in digestive process, viii, 356-7, 358, ix, 232, 234-6, x, 319-21; functions in maintenance of life, ix, 21-3; habit in functioning of, 251; in infants, 346; muscles of, ix, 74, 85, 160-1, 162; nervous connections of, 164-5; position in circulatory system, ix, 198; smell effects, xi, 69; supporting framework, ix, 71; ulcer of, cause, x, 224; worry effects on, ix, 165; X-ray examination of, x, 373 Stomach Catarrh, x, 253 Stomiatidæ, xii, 23 Stone, Cheselden's operation for, x, 92; Oath of Hippocrates on, 19 Stone Age, agriculture, xiii, 209, 210; bow and arrow in, xv, 214; end of in Europe, xvi, 50; fire uses in, xv, 229; tools of, v, 13, 14, xvi, 47 (see Eolithic, Neolithic, Paleolithic Periods) Stone Axes, primitive, xv, 192 (fig.) Stone Buttons, xvi, 29 Stonehenge, xv, 271-2; solstitial orientation at, ii, 26 Stone Flies, xii, 106 Stone Lilies, iii, 268-70, 256 (Pl. 14) Stone Meteorites, ii, 291, 292 Stone Mountain, exfoliation on, iii, 24 Stone Pestles, xv, 238 Stone Structures, ancient, xv, 269-72 Stones, art of breaking, v, 12; breaking of, by freezing water, iv, 150-1; cutting in ancient Egypt, xvi, 67 Stone Tools, beginning of, v, 11, 12-14; evolution of, xv, 102-10 Stone Walls, cleaned by air jets, v, 185-6 Stoney, on planetary atmospheres, ii, 231-2 Storage Batteries, iv, 298-300, vi, 130, 144-51, vii, 375; care in automobiles, vii, 121, 144; charging of, vi, 331, 332, 333; chemical action in, viii, 167-9; in farm plants, vii, 233 Storage Battery Reserves, in power plants, vi, 382-3 Storks, xii, 254, 255 Storm Cards, i, 279, 382 Storm Signals, i, 282-3 Storms, i, 134-9; electrification by, vii, 212-13; height in atmosphere, i, 17; prediction of, 239, vii, 218; rainfall of, 110-11; wave power in, xiv, 299-300, 303 (see also Cyclones, Hurricanes, Thunderstorms) Storm Waters, i, 382; in sewage systems, viii, 324 Stormy Petrels, xii, 252 Storm Weather, business effects, i, 264 Stove Blacking, graphite in, viii, 43 Strabo, geography of, xiv, 3, xvi, 98; on Vesuvius, xiv, 313 Strata, elastic, iv, 82, 157, 158 Strain Sensations, xi, 124; in time estimation, 195-6 Straits of Calais, tidal basin, v, 176 Strangulation, effect on blood color, ix, 261 Strata, Stratified Rocks, iii, 382-3; ages, how determined, 17-19; formation of, 13, 54; land forms in, 139-40, xiv, 80-99; oldest by planetesimal theory, iii, 163; significance of, 12; thickness in folded mountains, 132, xiv, 228-9; thickness of series, iii, 17 (see also Sedimentary Rock) Stratiography, defined, iii, 383 Stratosphere, i, 20, 382 (see also Upper Air) Stratus Clouds, i, 98, 102-3, 103 Strawberry, fertilization, xiii, 139-40; fruit, 59; in rose family, 197; origin, 227; poisoning from, x, 212; production of new plants, xiii, 166 Strays, wireless disturbances, i, 162-3, 382 Stream Gravels, precious stones in, iii, 327, 328 (see also Placer Deposits) Stream-line Construction, v, 236 Stream Piracy, iii, 38-9, xiv, 177-83 Street Cars, reading on, xi, 373-4 Street Cleaners, vacuum, v, 137 Street Fakers, crowd psychology and, xi, 328 Street Lighting, vi, 278-9 Street Railways, air-propulsion in, v, 133; electric, vii, 180-93, 197; underground wires, 11-14 (see also Electric Traction) Streptococci, x, 195, 221 Stress, elastic, iv, 157, 158 Streubel, Prof, Ernest J., author Electricity, Vol. vi, vii Striated Rock, xiv, 56 Strikes, crowd psychology in, xi, 330 Stringed Instruments, development of, xv, 317-18 Strings, vibration of, iv, 216-17, 222-3 Stromboli, xiv, 314, 317, 321 Strombus Gigas, xii, 74 Strontium, affinity strength, viii, 128; atomic weight and symbol, 383; flame color, 301; in calcium group, 148; specific gravity, 384; test for, 287, 289 Structural Topography, xiv, 94 Structure, geological, iii, 383 Struggle for Dominance, in plants, xiii, 337-8, 348-50, 354, 375 Struggle for Existence, xv, 21-2; among plants, xiii, 11, 21-2, 27-8, 32, 38-9, 87, 365, xvi, 167; Darwinian theory, xvi, 150-1; emotions developed by, xi, 138; in inanimate institutions, xv, 29; in man, 25-6, 27; in tropical forests, xiv, 367 Struve, astronomer, ii, 312, 313 Strychnine, action on nervous system, ix, 132-3; an alkaloid, viii, 240 Strychnos Apple, origin, xiii, 227 Stubbornness, muscular tenseness and, xi, 372 Stuber, Dr., vi, 15 Stuffiness, cause of, i, 321 Stuffing Box Packing, v, 99 Sturgeons, xii, 151-2 Style, of flowers, xiii, 46; in grasses, 182; in plant reproduction, 118, 119, 134, 135, 140, 141 Styria, hail shooting, i, 341, 342 Subærial Agents, of rock destruction, xiv, 47-79 Sub-Atomic Energy, Eddington on, ii, 384 (see also Atomic Energy) Subconscious Mind, xi, 47; in dreams, x, 364, 365, xi, 294-5, 290-300; evasions of consciousness, 300, 305-6; in learning, 212-13, 214; in reasoning, 244-6; repressed ideas in, x, 355-6, 361, xi, 350-1; revealed in smiles, 357; work retarded by fear, 212-13, 214 (see also Autosuggestion, Suppressions) Submachine Gun, v, 367-8 Submarine Bells, i, 191 Submarines, iv, 105-7, v, 195-202; Diesel engines in, 162; gyro-compasses of, iv, 254, v, 340; Holland and Lake, 382; motors used, vi, 239; photographic spotting of, in World War, i, 47 Submarine Torpedoes, v, 373-4; gyroscopes in, 340 Submerged Object photographic discovery of, i, 47-8 Submerged Plants, fertilization, xiii, 149-52 Submerged Rocks, aerial mapping of, 47 Submergence, Coasts of, iii, 37-8, 57, xiv, 253, 255-62 Subsequent Streams, xiv, 159, 174 Subsidence of Land, coasts resulting from, iii, 37-8, 57, xiv, 253, 255-62; during Ice Age, iii, 80; effect on streams, xiv, 40, 163-4; in relation to coal formation, iii, 199; of ocean bottom, 83, 168, 206; various instances of, 78, 79, 80-2, 133, 225 (see also Level Changes) Substantive Variations, xvi, 155 Subsurface Conditions, exploration of, v, 262-3 Subways, Beach's pneumatic, v, 138 Subway Train Systems, vii, 197-8 Succession, association by, xi, 197 Sucking, mouth deformities from habit of, x, 314; reflex in infants, ix, 349 Sucrose, viii, 226, 242 (see Cane Sugar) Suction, due to atmospheric pressure, i, 25, v, 112; work by so-called, 137 Suction Dredge, v, 257-9 Suction Pump, iv, 126, v, 112-13; atmospheric pressure in, i, 25; early ideas of, iv, 26-7 Sudbury, Ontario, nickel of, xiv, 238 Suess, Prof. coast classification of, xiv, 247; on North Atlantic Ocean, 290 Suez Canal, tropical disease control at, xiv, 356 Sugar, calories in, ix, 299; chemical structure and properties, viii, 225-7, 309-10, ix, 26; digestion and absorption of, viii, 227, 356, ix, 230, 243, 290-4, x, 270; fermentation of, viii, 213-14, 227, 248, 249; fermentation in intestines, ix, 248; food value and requirements, viii, 227, 364-5, 366, ix, 27, 289-90, 300-1, x, 256, 269, 273 (see also Carbohydrates); history of use, viii, 227, xiii, 215; in blood, cause of excess, x, 330; in blood, liver action on, 329; in blood, regulation of, ix, 290-3, x, 329, 330; in blood, increase in excitement, 293, xi, 138; in fruits, viii, 365; in urine, ix, 292-4, x, 330, 343; in various foods, ix, 300; kinds and sources, viii, 225-7, 242-3, ix, 230, xiii, 214-16; making and storage of, by plants, ix, 26-9, xiii, 79, 80, 81, 82, 83, 214, xiv, 65; maltose as substitute, viii, 243; manufacture of, iv, 170; preserving by, viii, 372; production, 242-3; produced artificially, xvi, 142; respiratory quotient with, x, 270; "showers", i, 357; taste sensations, xi, 71-2; testing of, by polarized light, iv, 355-6; vanilla from, xiii, 259 (see also Beet Sugar, Cane Sugar, Maple Sugar) Sugar Beet, xiii, 214, 216; extraction method, viii, 242 (see also Beet Sugar) Sugar Cane, xiii, 214-15; ancestral home, 221; economic importance, 208; in grass family, 179, 181-2; growth and structure, 26; a monocotyledon, 178; stem, 183; sugar extraction from, viii, 242; sugar in stems of, ix, 27-8 (see also Cane Sugar) Sugar Growing, in Hawaii, v, 291 Sugar Maple, viii, 242-3; as forest tree, viii, 86; as source of sugar, 214 Sugar Pine, in Pacific forests, xiv, 374 Sugar Refineries, potash residues, viii, 344 Sugar Squirrel, xii, 278 Sugar Tongs, as levers, v, 24 Suggestion, Suggestibility, xi, 303-10; in advertising, 347; in crowds, 324-31; hypnotism as, 311, 313-14, 316, 317-22; outgoing reaction, 56; psychoanalytical uses of, x, 363-4 Sulphate Group, viii, 93; valence of, 94 Sulphates, viii, 76; formation of, 80, 83, 118; metal occurrence in, 130; test of, 285, 287, 290; in urine, x, 343 Sulphide Ores, viii, 76, 77, 130, 198; extraction of metals from, 131, 270-1, 271-2 Sulphite Pulp, v, 292, 293-4 Sulphites, test, viii, 290 Sulphonic Acids, viii, 236, 237 Sulphur, viii, 76-7; axis ratio, iii, 317; combustion of, viii, 11-12, 13, 57; compounds, 18, 77-83; electrification of, iv, 257, 259, vi, 12; energy in native, viii, 268; ignition of, viii, 53; in body tissues, 354; in coal, 118; in gunpowder, 145; in iron ore, iii, 356; in ores, viii, 77, 131, 270-1; in proteins, 351; in rubber making, 257-8; in steel, removal of, v, 320; melting requirements, iv, 162; occurrence in nature, iii, 339, viii, 19, 76, 118, 193, 198; odor of, iv, 131; plants uses of, viii, 337, ix, 29; presence in minerals, how determined, viii, 201; silver tarnished by, 13, 77, 171; uses, iii, 339, viii, 77; valences of, 94 Sulphur Dioxide, viii, 78 Sulphur Showers, i, 61, 355, 359 Sulphur Springs, viii, 77, xiv, 144 Sulphur Trioxide, viii, 78, 79, 80-2; affinity for water, 101 Sulphuric Acid, viii, 79-83; action on cellulose, 255; formation in body, x, 280; industrial importance, viii, 76, 78-91, 141, 275; molecular weight, 92; normal, 119; production, 81-2, 275, viii, 198; salts from, 83, 116; solubility, 112; strength, 115; used in electric batteries, vi, 58-9, 131-4; atomic weight and symbol, viii, 383; production by electrolysis, 125; production, iron pyrites used, iii, 336, viii, 167-9; use in explosives, 80; used in hydrogen preparation, 32-3; use in vacuum refrigeration, v, 355 Sulphurous Acid, viii, 78, 115 Sumac, family of, xiii, 200 Sumatra, apes of, xii, 381-3; cocoanut gathering, 378; continental island, xiv, 274; giant flower of, xiii, 363-4; rhinoceros of, xii, 306; tobacco production, xiii, 258 Sumatran Earthquake, "offsets" from, xiv, 335 Summation, Law of, xi, 21-2 Summer, efficiency in, i, 323; historic cold, i, 359-61, 361-2; hot or cool, how determined, xiv, 350; hot in America, i, 323; Indian, 361-2, 363; land and sea winds in, xiv, 346; regularity, i, 361-2 Summer Clothing, materials for, ix, 312 Summer-Day, temperature, i, 205, 382 Summer Forests, xiii, 368 Sun, ii, 165-73; Anne Bradstreet on, 19; atmosphere, i, 10, ii, 184-5, 225; atmosphere, heat absorption by, ii, 170; atmosphere, spectrum analysis of, iv, 362; atmospheric displacement of, iv, 327-8; axis direction, ii, 175; "backstays," i, 169, 367; center of solar system (see Heliocentric System); chemical composition, ii, 113, 114, 128, 185, 211, viii, 302; chromosphere, ii, 183, 184; corona, ii, 184, 219-26 (see Corona of Sun); comet tails and, 277, 278; coronas (atmospheric), i, 183; corpuscles from, in upper air, 144, 146, 158, 159, 160; crepuscular rays, 169; distance, early ideas, ii, 32, 83, 84; distance, how obtained, 27-9, 91-2, 121, 129, 132, 166-7, 191, 263; distance measured by Richer, 59; disturbances affecting earth's magnetism, vi, 40; disturbances in relation to aurora, i, 160, 161; "drawing water," 169, 382; eclipses (see Solar Eclipses); electromagnetic waves from, vii, 260; electrons shot off by, i, 144, 146; erratic amplitude, ii, 25; faculae, 176, 182; goal and quit, 305; "green and red flashes," i, 170-1; habitability, ii, 252; halos, i, 100, 103, 178, 180, 181; heat from, iv, 181-2, 183, 194; heat from, atmospheric effects, i, 123; heat from, modified by volcanic dust, 58-9; helium in, 12; Herschel's studies, ii, 16; Hipparchus on motions, xvi, 90; hypothesis of origin, iii, 160, 161; light and heat, ii, 168-71; light deflection by, 81-2; magnetism, 154, 156, 175, 176-9, 186; motion toward Lyra, 122, 137, 305-6, 317; movement eastward, 195-6; observation methods, 172-3, 19; parallax, 59, 92; photosphere, 173, 184; photosphere, studies, 127, 129; physical constitution, 183-4, 185; position in solar system, 50, 51, 163; prominences, 179-83, 184, 211, 214; Ptolemaic theory, 35; pull on planets, 65; radiant energy, 170, 384, vi, 269-70, ix, 114-15; radiation, atmospheric effects, i, 324; radiation, biological importance, 211; radiation, measurement of, 88; radiation, physiological effects, 324-5; radiation, weather effects, 218-19, 242, ii, 186-8, iv, 194; radiative equilibrium, ii, 382, 383-4; reversing layer, 184, 211, 212; "rising" of, xvi, 12; rotation, ii, 54, 129, 175, iii, 159; rotation discovery, xvi, 103; rotation studied by spectroscope, ii, 120; shrinking of, 170; size and shape, 28, 162, 167; solstices observed in ancient Egypt, 25-6; source of energy, v, 177, viii, 267, 334, 347, 349, 350, ix, 25-6, 27, xiv, 32, 75; source of organic life, xii, 11; Spectrum of (see Solar Spectrum); stars resembling, ii, 117, 118 (see Solar Stars); stellar magnitude, 296; studies at Mt. Wilson, 152, 154; temperature of, iv, 194; tides and, ii, 70, xiv, 291, 292; variable star, ii, 171; variations in heat, iii, 248; weight, ii, 76, 77, 78, 167-8; winds caused by, xiv, 347 Sunburn, vii, 249, 253, x, 254; chemical cause, i, 324-5; X-ray burns and, vii, 250 Sundews, xiii, 40 Sundial, limitations, v, 58 "Sun Dogs," i, 180, 181, 382 Sunflower, in daisy family, xiii, 206; restricted area, 320 Sunk Country of Missouri, iii, 98 Sunlight, atmospheric effects on color, i, 165-6, 167-71; colors of, 165, ix, 115; disease and, x, 240, 291, 292; energy utilized, v, 177-8; heat of, iv, 181-2, 183; intensity compared with starlight, vi, 272; leaf protection against excess of, xiii, 105-6; penetration of ocean by, xii, 22; plants and, viii, 335, 336, ix, 27, x, 253, xiii, 14, 76-7, 79, 80, 81, 84-90, 114, 361-3, xiv, 65, 365-6, 367; physiological effects, i, 324-5; results of absence in forests, xiii, 369, 370; spectrum of, viii, 302; struggle of leaves for, xiii, 27-8, 38-9 (see also Place in the Sun) Sunny Dispositions, xi, 55 Sun-Pillar, i, 376 Sunrise, atmospheric refraction of, iv, 323, 327-8; green flash of, i, 170-1; red and grey, 166; succession of lights and colors, 167, 169; temperature at, 76 Sunset, atmospheric refraction of, iv, 323, 327-8; green flash of, i, 170-1; red and gray, 166; succession of light and colors at, 167-9 Sunshine Recorders, i, 86-8, 382 "Sunshine State," i, 86 Sun Spots, ii, 174-9, 184, 185; corona and, 182, 184, 212, 220, 224; discovered by Galileo, 54; method of examining, 172; periodicity, 171, 175-6, 185, 186; photographic study, 127, 129; prominences and, 182; radiation in relation to, 171; rotation of sun proved by, 120; spectrum of, 117, 153, 155; summer of 1816 and, i, 360; weather effects, 16, 242, ii, 186 Sunstone, iii, 329 Sun Stroke, x, 252 Sun Valve, v, 331-2 Sun-Worship, at Stonehenge, xv, 272; of agricultural peoples, 342; of ancient nations, ii, 20, 23, 24, 25-6, 165 Supan, coast classification of, xiv, 247, 248, 249; on landlocked areas, 190; on river courses, 155; on water circulation, 134 Supercooled Liquids, viii, 304-5 Super-Electric Zone, vi, 384 Superheated Solutions, viii, 304 Superheated Steam, v, 140 Superheaters, vi, 354 Superheating, method and use of, iv, 170-1 Superimposed Streams, iii, 137, 233-4, xiv, 170-4 Superior, Lake, xiv, area and depth of, xiv, 204 Superposition, in distance perception, xi, 183 Supersaturation, viii, 113 Superstitions, dread of, x, 364; in ancient medicine, x, 12; in savages and civilized races, xv, 354-5; weather, i, 334-5 Suppressions (Emotions, Wishes), xi, 140-2, 206, 257; getting rid of, 381-2; laughter in relation to, 350-1, 353-4, 355-6, 357 (see also Repressions) Suprapubic Cystotomy, x, 57 Suprarenal Capsules, xi, 273 Suprarenals, x, 347; Addison's disease of, 113; affections of, 352 Surf, destructive work of, xiv, 45, 47 Surface Senses, xi, 63, 64 Surface Waters, as water supplies, viii, 318 Surgery, antiseptic and aseptic, x, 146-8 (see also Antiseptic Surgery); history of development, 13-14, 24-5, 27, 32, 35, 37, 38, 39, 41, 43, 55-8, 78-81, 90-7, 121-5, 129-31, 144-9, xvi, 63, 108, 181, 182-4, 185; hypnosis in, xi, 316-17; made a scientific profession, x, 104-5; plastic, 57, 189, 384; separation from general medicine, 16-17, 35, 38, 39, 41, 43; three perplexities of early, 14, 123, 134, 148; X-rays in, vii, 256 Surgical Dressings, sphagnum in, xiii, 160-1 Surinam Eel, vi, 16 Surinam Toad, xii, 175 Süring, balloon ascension, i, 18, v, 225 Surprise, effects of strong, xi, 21 Surra, disease, x, 168 Surukuku, xii, 234 Surveying, by aeroplane, i, 46-7; history of development, xvi, 68-9, 91, 98 Survival of the Fittest, x, 136, xiii, 334-5, 346, xv, 23, 24-5, xvi, 150-1, 152; in human race, xv, 27, 47-8; in plants, xiii, 12, 89; in social institutions, xv, 30 (see also Struggle for Existence) Susceptibility, racial, xv, 50-2 Susquehanna River, cutting of present course, iii, 36, xiv, 168-9; drowned valley of, 40, 255-6; former extension and branches, 256; gap of, 51, 167; heterogeneous stream, 155; in Glacial Epoch, 171; superimposed character, iii, 137, 233; transverse course, xiv, 99, 154 Susquehanna Valley, origin, iii, 232 Sutlej River, aerial mapping of, i, 46 Suttee, xv, 335 Swallowing, ear pressure equalized by, xi, 101; effect on sphincter muscles, ix, 231; movement of, 82; operation, how learned, xi, 37-9; saliva necessary to, ix, 228-9 Swallows, xii, 268; seed dispersal by, xiii, 341 Swamp Azalet, xiii, 208 (fig.) Swamps, coal-forming conditions in, iii, 199; ditch-digging in, v, 216; draining of, by trees, xiv, 379; formed by filling lakes, 212; of Coal Age, iii, 200, 253, 254, xiii, 309, 312; plant formations of, xiv, 372; shrubs suitable for, xiii, 275 Swann, Dr. W. F. G., i, 145, 146 Swans, xii, 257, 258-9; wing power of, xv, 18 Swape, v, 18-19 Sweat, ammonia in, ix, 276; body heat regulation by, 169, 315-16, 317; control of, 168, 169; in sleep, xi, 285; odor, to what due, ix, 315; poisons exhaled in, 269; purpose, xi, 271, 272 (see also Perspiration, Sweat Glands) Sweat Center, ix, 315, 316 Sweat Glands, ix, 314; body heat regulation by, 169, 314-16; fever effects on, 318; nervous control of, 168, 169; water and waste removal by, 271, 274, 276 "Sweating," of ice pitchers, i, 121 Sweat Shops, air poisons in, ix, 270; tuberculosis and, x, 291 Sweden, coast of, xiv, 247; crustal movements, iii, 80; fiords of, xiv, 259; Ice Age in, iii, 246; nitrogen fixation, i, 36 Swedenborg, theory of universe, ii, 367 Swedish Language, xv, 162 Sweet, taste of, ix, 95, xi, 70, 71, 72 Sweet Alyssum, xiii, in mustard family, xiii, 197 Sweet Fern, xiii, 192 (fig.) Sweet Gum Tree, petals absent in, xiii, 195; in landscaping, 271-2 Sweet Pea, flower, xiii, 138 Sweet Potato, xiii, 218-19; American origin, xiii, 221, xiv, 382; root of, xiii, 13 Sweetsop, origin, xiii, 227 Sweet Woodruff, xiii, 205 Swellings, cause of, ix, 222 Swift, Dean, on moons of Mars, ii, 241 Swift River Valley, iii, 96 (Pl. 5) Swifts (foxes), xii, 344 Swifts (lizards), xii, 203 Swim Bladder, xii, 136 Swimming, equilibrium sense in, ix, 90; reflex processes in, 155-6 Swine, xii, 310-11 Swiss, in Alpine group, xiv, 49 Switchboards, of power plants, vi, 360, 375; remote control by, 100-1 Switches, electroller, vii, 68; inverse-time, 37; oil, 41 Switzerland, cirques of, xiv, 58; civilization of, xv, 131; independence due to Alps, xiv, 243-4; lakes of, 200; ocean trade of, 306; population and industries, 241-2; winds, i, 133; in World War, xiv, 244 Sycamore Tree, calyx and Corolla absent, xiii, 46; leaf buds, 34 (see also Plane Tree) Sydenham, Thomas, x, 72-4, 81, xvi, 108-9; malaria in time of, 10, 155; on "comatose fever," 301; pupils of, 76, 77; smallpox studies, 100 Syllogism, invention, xvi, 88 Sylvius (De la Boe), x, 69-70, xvi, 108; Locke on, x, 75 Sylvius, Jacobus, x, 51, 52-3 Symbiosis, x, 221, xiii, 98-9 Symbols, of chemical elements, viii. 91, 383 Syme, James, x, 144 Symmetry, idea of, inborn in man, xv, 251; in organisms, major and minor, xvi, 155 Sympathetic Nervous System, x, 352-3, x, 113, 134-5, 137 Sympathetic Vibration, iv, 225-6, vii, 118, 261-2 Sympathy, instinct of, xi, 56; empathy and, 172; suppression of, 141 Synæsthetic Images, xi, 222 Synapses, defined, xi, 20; retardation at, 20, 21, 71, 154 Synchronism, defined, vii, 376 Synchronizing Action of alternators, vi, 383-4 Synchronous Charts, i, 214-15, 383 Synchronous Condensers, vi, 262 Synchronous Converters, vi, 343-8 Synchronous Motors, vi, 241, 255, 256-63; in motor-generator sets, 332, 342 Synchronous Speed in motors, vi, 241, 247 Synchronous Vibration, vii, 118, 261-2 Synclines, iii, 85, 133, 383 (fig.); hot springs and, 128 Synodic Period, of moon, ii, 196 Synonyms, botanical, xiii, 171 Synoptic Charts, i, 215, 383 Synthetic Races, xii, 134 Syphilis, history of, in Europe, x, 60; Hunter's study of, 95; mercury for, 60, 104 Syria, gazelles of, xii, 327; Rift Valley or Ghor, xiv, 120-1 Syrinx, of birds, xii, 248, 249 Systole and Diastole, of arteries, x, 62, 63-4, 65; heart, 65 Tabit ben Korra, ii, 38 Table-lands (see Plateaus) Table Mountain, South Africa, xiv, 225; cloud cap, i, 105, 383; fog drip, x, 351 Table Mountains (mesas), xiv, 81, 82 Table Salt, impurities in, xiv, 296 Tacking (sailing), v, 182, 188 Taconic Range, iii, 188-9, 190, 192, 210; antiquity of, xiv, 235 Tadpoles, xii, 175, 179, 181; regeneration in, 170 Tagliacozzi, x, 57-8, 189 Tahiti, vanilla production, xiii, 260 Tahiti Apple, xiii, 227 Tahoe, Lake, iii, 153-4 Tails, rudimentary, in man, xv, 56 Talbot, Fox, xvi, 192 Talc, iii, 339-40; chemical composition, viii, 90 Talking Machines (see Phonograph, Graphophone) Tallow, animal fat, viii, 246 Tallow Candles, viii, 247 Talman, Prof. C. F., author Meteorology, Vol. i Talons, xii, 260 Talus, defined, iii, 383 Talus Slopes, in arid regions, xiv, 77-8; of mountains, 233 Tamandua, xii, 282 Tamarinds, origin, xiii, 227 Tamerlane, grandson of, ii, 39, 300 Tamia-caspi, i, 352 Tampers, pneumatic, v, 135 Tampico, harbor of, xiv, 266 Tan, skin, vii, 249, 253 Tanagers, xii, 245, 269 Tanganyika, Lake, size, xiv, 204 "Tanks", in World War, v, 218, 384 Tannic Acid, in tea, xiii, 231 Tannin, uses of, viii, 257, 259 Tanning, of hides, viii, 257; in ancient Egypt, xvi, 73 Tantalum, symbol and atomic weight, viii, 383 Tapegrass, fertilization, xiii, 150-1 Tapeworm, x, 200, xii, 45; food of, ix, 18; motions of, 73 Tapioca, source, viii, 243 Tapirs, xii, 304, 306 Taproots, xiii, 16, 17, 18 Tar, constituents of, viii, 333; production and uses, 253 Tarantella (dance), xii, 93 Tarantulas, xii, 93 Tarnishing, of metals, viii, 13, 77, 100 Tarpons, xii, 154 Tartar Astronomers, ii, 39 Tartar, on teeth, x, 315-16 Tartaric Acid, viii, 136, 222-3, 336; asymmetric atoms of, 309-10; Pasteur's study of, x, 137 Tasmania, aborigines, iii, 303, 304; animals of, xii, 277-8; continental island, xiv, 276; leafless yew-tree, xiii, 30 Tasmanians, hair of, xv, 38; in black race, 37 Taste (sense), ix, 94-5, 96, xi, 69-77; in infants, ix, 350-1; mingled associations with, xi, 64, 127; phonisms of, 222 Taste Buds, ix, 94, 95; related to end-buds of fishes, xii, 137 Tastes, agreeable, digestion aided by, ix, 98, 240, x, 320 Tattooing, xv, 257 (fig.), 258-9 Taughannock Falls, iii, 50 Taylor, Bertha Fanning, xiii, 4 Taylor, Fred W., v, 54-5, 383 Taylor, Dr. Griffith, i, 324 Taylor, Prof. Norman, author BOTANY, Vol. xiii Tea, history and production, xiii, 227-31; over-boiling, 231; polyuria from drinking of, x, 344; wakefulness from, ix, 219 Teakettles, heating of, iv, 182-3 Tea Plant, xiii, 228, 229-30; ancestral home, 221 Teak-wood, source, xiv, 383 Tear Gases, viii, 263 Tear Glands, blood supply of, ix, 197; control of, 162, 163 Tears, cause, xi, 23; taste sensations and, 76 Technical Terms, glossary of, iv, 381-4 Tectonic Topography, xiv, 94 Tedium, xi, 194-5 Teeth, ancient birds with, iii, 296, 297, xii, 241-3; care of, ix, 228, x, 313-16; decay of, cause and results, 312-13, 314; decay from emotional strain, xi, 142; defective, mental impairment by, 373; diet and, x, 265, 314-15; diseased, fatigue from, xi, 279; electric treatment, vii, 237; enamel of, ix, 13; grinding of grains by, xv, 237-8; infections from, x, 202, 218, 222, 225-6; killing of nerves of, ix, 187, 188; loss of, results on jaws, 57; malnutrition from bad, 228; modified scales, xii, 134; mutilations of, by savages, xv, 260; of carnivores, xii, 332-3, 389; of manlike apes, iii, 303; of Neanderthal man, xv, 98 (fig.); of rodents, xii, 286; of Tertiary mammals, iii, 298, 300; poisons from decaying, ix, 269-70; pus pockets at roots of, 187, 188; replacing of sound, x, 56; temporary and permanent, 313-14; ulcerated, ix, 56; X-ray examinations, x, 373, vii, 254 Teguexins, xii, 208 Tejus Lizards, xii, 208 Telautograph, vi, 98 Teleosts, iii, 285, xii, 142, 151-66; eggs of, 141 Teledu, stinking, xii, 348 Telegraph, Telegraph System, iv, 292-4, vii, 108-18, 376; cells used, vi, 127, 140; etymology of word, vii, 91; invention, 108, vi, 24, xvi, 188; protection against lightning, vii, 49-50; sounders, 375; submarine, vi, 24 Telegraph Codes, vii, 108-9 Telegraph Plant, xiii, 114 Telegraph Plateau, xiv, 288 Telegraph Poles, in desert regions, iii, 72-3 Telegraph Wires, humming of, i, 194-5 Telephone Exchange, brain compared to, xi, 15-16; central nervous system compared to, ix, 129 Telephone, Telephone System, iv, 305-6, vii, 91-107, 376; automatic, vi, 87, vii, 92-3, 106-7; cells used, vi, 138, 142; condensers in, 285, 304; invention, v, 381, vii, 92, xvi, 188; magneto-generators, vi, 215; number in New York, vii, 75; protections against lightning, 50; receiver, electromagnet of, vi, 99; simultaneous messages, vii, 118-19; vacuum tubes in, 280; vibration rates of, ix, 101; wire used, vii, 314 Telephony, prominent names in, vi, 26 Telescopes, ii, 93-110, iv, 345-6; comet-seekers, ii, 274; first used by Galileo, 54; first eclipse seen by, 210; Galileo's, xvi, 103; lens improvements, 125; limitations due to atmosphere, ii, 140, 201-2; modern, 18, 143 (see also Bruce, Hooker, Leviathan, Yerkes Telescopes); use in astronomical photography, iv, 372-3 Telluride Ores, iii, 366 Tellurium, classification place, viii, 182, 183; symbol and atomic weight, 383 Temperament, classes of, xi, 153-9 Temperate Forests, xiii, 366-73, xiv, 366, 370-1; timber supply from, 382-3 Temperate Zone, civilization in, xv, 122, 123, 127, 383, xiv, 344, 357-9; most favorable to man, xi, 51; weather, how determined, xiv, 349-50; winds, i, 127-8, 135, 137, xiv, 345-6, 349 Temperature, absolute, viii (see Absolute Scale); altitude and, i, 19, 20, 208, xiv, 364-5; barometric pressure and, iv, 122-3, 124, 125; body (see Body); climate classification by, i, 208; colors in relation to, iv, 361; critical (see Critical Temperature); daily range, xiv, 247-8; dependent on atmospheric constituents, i, 14-15, 16, 58-9, iii, 248; determining factors, i, 208, xiv, 344-7; electrical conductance affected by, iv, 301; equalization by water, viii, 37, 38; gas pressure and, iv, 139-42, viii, 107; heat and, iv, 139-40, 144-5, 153-4; high and low attained, v, 345, 348; highest atmospheric, i, 209; human control of, 332-3; human efficiency and, i, 323-4; human feelings of, 317-18, 320-1, ix, 93-4, 319-21, xi, 112-14; humidity and, i, 76, 77, xiv, 352-4; infant's adjustment to, ix, 352; latitude and, xiv, 344-5; lowest atmospheric, i, 209-10; maximum and minimum, i, 75-6; mean, 203-4; measurement of (see Thermometers); measuring of high, iv, 137-8, vi, 62-3; metabolism affected by, ix, 37, 78-9; musical instruments affected by, iv, 231-2; observations and records, i, 203-5; of deep sea, xii, 21-2; of electric arc, iv, 312; of electric furnace, vii, 302, xvi, 189; of liquid air, i, 31, viii, 68; of meteors, ii, 285, 290; of oxyacetylene blowpipe, i, 33; of stratosphere in different latitudes, 20; of sun, ii, 169, iv, 194; optimal, xi, 51; physical state and, viii, 303-5; plant distribution determined by, xiv, 364-71, 374-7; plant societies in relation to, xiii, 357, 381; range of, on earth, ii, 243-4; range possible for life, i, 32, ii, 243-4, 245, 249, v, 348-9, x, 250-1; rise of, to what due, iv, 144; scientific meaning of, 139-40, 144; seeking of favorable, xi, 51-2; sensations of, ix, 93-4, 314, xi, 112-14; sensible, i, 318; sound speed and, i, 186-7, iv, 198-9; subterranean layers of, xiv, 12-15; susceptibility to change of, x, 240; sun-spot effects, i, 16; variability, i, 204-5; variations by night and day, iv, 134, 183; variations, effect on timepieces, v, 71-2, 73; variations, human effects, x, 238-9; variations and rock weathering, iii, 23-4, 72, xiv, 41, 62, 74, 75, 77-9, 233; ventilation factor, viii, 331, 332; volcanic dust effects, i, 58-9; winds in relation to, 124, 126-7, 131, 293, xiv, 345-7 (see also Heat) Temperature Charts, i, 206 Temperature Inversion, i, 375 Tempered Scale (music), 4, 208-9 Ten Commandments, xv, 368 Tender Emotion, xi, 146, 147, 149 Tendon of Achilles, ix, 76 Tendons, ix, 59, 79; early surgery of, x, 79, 96; sensations of, xi, 124, 125 Tendrils, xiii, 28; movements of, 111-12; on leaves, 38 Teneriffe, Smyth's experiment on, ii, 141; volcanic nature, xiv, 277, 316 Tennessee, non-glacial topography of, xiv, 56; underground streams of, 149 Tennessee River, former course, xiv, 186 Tennis, "cutting" of balls in, iv, 67, 68-9 Tennyson, in Holmes' "goodly company," x, 134; quoted, i, 136, 183, iii, 11, xi, 33 Tension Spring, air as, v, 136-7 Tents, Indian, xv, 266 Teratoma, x, 120 Terbium, symbol and atomic weight, viii, 383 Term Hours, i, 203, 383 Terminal, of moon, ii, 28 Terminal Moraines, iii, 67; lakes formed by, xiv, 202; of great Ice Sheet, iii, 67-8, xiv, 59, 200, xv, 74-6 Terminal Voltages, vi, 186, 188, 189 Terminals (see Railroad Terminals) Terminator (astronomical), ii, 194, 202 Termites, xii, 110, 125 Terns, xii, 264 Terpenes, viii, 240, 251-2 Terra Firma, iii, 76 Terraces, defined, iii, 383; of California, 224 Terrapins, xii, 189-90 Terrestrial Refraction, i, 171, 380 Terror, exhaustion from, xi, 135-6; expression and origin, 131-3 Tertiary Period, iii, 20, 221-36, 383; appearance of man in, xv, 72; development of mammals in, xii, 271-2; divisions and species surviving, xv, 71; plants and animal life, iii, 257, 279, 297, 298-9, 300, 301-2, 303, xii, 104, 154, 243, 283, 366; remains of man in, v, 11 Tesla, Nicola, vi, 26 Testudinidae, xii, 188 Tetanus, negro susceptibility to, xv, 51 (see Lockjaw) Teptonic Races, in Nordic group, xvi, 48 Texas, chalk deposits, iii, 216-18; chapparal of, xiv, 379; coasts of, iii, 57, xiv, 251, 262, 263; cotton, xiii, 237; dust whirlwinds, i, 60; mercury production, iii, 370; monsoons, i, 131; oil wells, helium from, iv, 108; peccary of, xii, 311; stock-raising system, xiv, 383 Texas Fever, xii, 98 Textile Machinery, v, 268-83, 376-7; induction motors in, xi, 256; of ancient Egypt, xvi, 72-3 Textiles, chemistry of, viii, 254-8; Egyptian, xvi, 72-3; fireproofing of, viii; starch in, 243 Thackeray, W. M., brain weight, xv, 39 Thales, discovery of magnetism, vi, 11; eclipse predictions, ii, 9, 27, 209-10; scientific teachings, xvi, 76-7, 77 Thallium, symbol and atomic weight, viii, 383 Thallophytes, iii, 250, 251, 252, 256 Thallus, of ferns, xiii, 156-7; none in mosses, 163 Thames River, former tributary of Rhine, xv, 76; tidal basin, v, 176; true mouth of, xiv, 270 Theatres, color induction in, xi, 95; use of ozone in, vii, 353-4; wiring, 57 Thebes, Egyptian, xvi, 64, 65, 67, 70; papyri discovered at, x, 12 Thenard, chemical work, xvi, 162 Theobromin, polyuria induced by, x, 344 Theology, Creek, Roman, medieval, xvi, 99-100, 115 Theophrastus, zoölogical work, xvi, 126 Therapy, Therapeutics, x, 379-84; aeronautics in, i, 51; ancient systems of, x, 12, 13, 21-2, 26, 380; Brunonian system, 89-90; climatological, i, 331, x, 383; drug, 21-2, 380-1; electricity in (see Electro-therapeutics); hypnosis in, xi, 317; Locke and Holmes on, x, 74-5; modern, 380-4; nihilism doctrine in, 113; open-air, 240-1, 291; Rowntree's categories of, 380; Stahl's system, 85; Sydenham's glossary of, 74; X-rays in, vii, 251, 252-3, 255-6 Thermal Belts, i, 259, 383 Thermal Couples, vi, 62-3, 72; electron theory, vi, 123-5; power tables, vii, 383; source of energy, vi, 129 Thermal Springs, xiv, 143-5 (see also Hot Springs) Thermal Unit, v, 350-1 Thermionic Valve, vi, 125 Thermodynamics, iv, 384; great laws of, 189-94 Thermo-electricity, vii, 376 Thermo-electric Powers, vii, 383 Thermograph, i, 76, 77, 383 Thermo-junction, i, 318 (see Thermal Couples) Thermometers, i, 72-6, 383, iv, 135-8, 145; as comfort measures, i, 318; comparison of scales, iv, 137 (fig.), xiii, 27, 384; development, i, 68-9; drugstore, 266; Galileo's, x, 71; metallic, iv, 146-7 Thermometer Screen, i, 375, 383 Thermos Bottle, construction and use, iv, 184-5; invention, vii, 323; principle, i, 31, viii, 68 Thermoscope, i, 69 Thermostat, iv, 148-9, 384, vii, 87 Thermostatic Regulators, vii, 148 Thermotaxis, xi, 51-2, 61 Theromorpha, xii, 184-5; mammals developed from, 271 Thibet (see Tibet) Thigh, bone of, ix, 68, 70 (fig.) Thimbleberry, xiii, 199 (fig.) Thinking, law and process of, xi, 201 (see also Thought) Thinness, x, 277 Third Dimension, perception of, xi, 173-83 Third Rail System, vii, 187, 189, 197-8, 199 (fig.) Thirst, exercise effects, x, 303-4; sensation of, ix, 87, 88-9, xi, 66-7; sense of, in infants, ix, 350 Thomas, Holt, on airships, i, 42 Thomas of Sarzona, x, 44 "Thomas W. Lawson," schooner, v, 188-9 Thompson, Benjamin (see Rumford) Thompson, S. P., vi, 26 Thompson, William (see Kelvin) Thomson, Elihu, vi, 26 Thomson, J. J., cathode ray studies, xvi, 193; electron theory of, iv, 55, vi, 26; experiments on gas cooling, i, 30 Thomson Water Meter, v, 87 Thorax, diagnosis of diseases of, x, 98-9, 109; of insects, xii, 99, 102 Thoreau, on Indian summer, i, 362 Thorium, in soil and air, i, 143; radioactivity, viii, 184, 186; symbol and atomic weight, 383 Thorn Tree of Natal, xiii, 375 Thorpe, John, ring frame, v, 378 Thothmes, war chariot of, xv, 242 Thought, brain processes in, ix, 147-53, xi, 15; cerebrum seat of, ix, 167; gray matter and, xv, 63; habits of, xi, 198, 203-4, 247; language and, xv, 143-45, 146; law and process of, xi, 201; need of changes of, ix, 138; nervous mechanism, xi, 19-20; physical essentials and costs, 25; speed of, 13 (see also Reaction Types); Stoic definition, 228; stream of, 193; similarity in laws of, xvi, 42-3 "Three Fates", painting, xi, 192 Three-Horned Beast, iii, 292 Three-phase, meaning, vi, 207 Threes, multiplies in plants, xiii, 176, 178 Threshing Machines, v, 248-9 Threshold of Sensation, xi, 71; of distance discrimination, 184, 185; in various senses, 80, 104-5, 111 Throat, as infection focus, x, 219, 224; connections with ear, ix, 101, 102 (fig.); drying of, in thirst, iv, 88; in speech production, ix, 83 Thrombosis, x, 336 Thrush, disease, x, 196 Thrushes, xii, 269 Thrust Bearings in Niagara Plant, vi, 374-5 Thrust Faults, iii, 87, 88 (fig.); examples, 90-2, 188, 219 Thugs, jaws of, xv, 43 Thulium, symbol and atomic weight, viii, 383 Thulis, astronomer, ii, 275 Thumb, flexibility of human, ix, 67-8; of apes and men, xv, 58-60 Thunder, i, 383; at sea, 193; cause of sounds, 192-3; distances heard, 188-9; explanation, vii, 210-11; general awe of, 201-2; large raindrops and, 215-17; reverberations of, iv, 238; speed of sound, i, 187 Thunderclouds, i, 102, 296; formation, 93 Thunderhead, i, 139 (fig.), vii, 217 Thunderstorms, i, 138-9, 383; astraphobia, 330; classes and causes, vii, 217-18; dangers and protection, i, 155-7; hail in, 106, 120, 373-4; lightning flashes, 149-52; potential differences in, vii, 352; St. Elmo's Fire in, i, 157; strays and, 163; vertical currents in, 293 Thunderstorm Recorders, i, 163, 383 Thuringian Forest, xiv, 238 Thylacine, xii, 277-8 Thyme, flowers, xiii, 205; origin, 265 Thymol, viii, 238, 333 Thyro-globulin, x, 351 Thyroid Gland, x, 347, 348; disorders and treatment, ix, 303-4, xi, 60-1; functions and disorders of, x, 348-52; inflammation of, and rheumatism, 224; operations on, 148; secretion used as drug, 382 Tiamat, or Chaos, xvi, 77 Tian Sham, xiv, 232 Tiber River, delta of, xiv, 263 Tibet, bears of, xii, 337, 338, xiv, 205, 211; marine deposits, iii, 235; plateau of, xiv, 97, 222, 232; polyandry in, xv, 286; rainfall, i, 111, xiv, 355; wild ass of, xii, 308; yak of, 330 Tibetans, in yellow race, xv, 37 Tickle, Tickling, sensation of, ix, 92-3; sense of, xi, 109, 114; laughter from, 355 Ticks, xii, 98 Tickseed, seed dispersal, xiii, 58, 343 Tick Trefoil, xiii, 58 Tidal Estuaries, formation of, xiv, 164, 255 Tidal Friction Theory, ii, 375-7 Tidal Power, v, 174-7 Tidal Races, xiv, 294 Tidal Waves, from earthquakes, xiv, 337; from Krakatoa eruption, iii, 101, xiv, 324 Tide-predicting Machines, v, 327 Tides, xiv, 291-5; Bacon's lunar theory, xvi, 101; cause, ii, 70, v, 177, xiv, 32, 291; erosive work of, 44-5; importance to shipping, 295; local ranges and peculiarities, 293-4; neap and spring, ii, 70; daily occurrence, xiv, 291-2, xiv, 292; power utilized, v, 174-7; "races", 294; variations in rise and fall, 292-3 Tides, Plastic, ii, 375 Tide Water, sewage disposal in, viii, 325 Tied Images, xi, 221 Tierra del Fuego, climate and forests of, xiv, 371 Tiger, saber tooth, in Europe, xv, 76; strength of, 18 Tigers, xii, 357-60; apes and, 362; Tiger Triton, 172-3 Tigris River, civilization on, xv, 123; mapping of flood areas, i, 47; rafts used on, xv, 264; union with Euphrates, xiv, 185 Tilefish, xii, 164 Till, glacial, iii, 67, xiv, 59, 61 Tillamook County, Oregon, rainfall, i, 112 Tilling Machines, v, 244 Timber, source of, xiv, 382-3 Timber Line, xiv, 233 Timber Wolf, xii, 340 Timbre, of sound, xi, 104 Timby, Theodore R., v, 380 Time, absolute and relative, ii, 80, iv, 16-18; coordinate for determining events, 16; geological (see Geological Ages); measuring of, v, 57-74; memory perception, xi, 208; Newton on absolute and relative, iv, 15; origin of word, xi, 192; perceptions of, 192-6; primary concept, iv, 14, 15; relative, Newton on, 15; relativity doctrine, xvi, 196-8; units of, iv, 15-16, 45, 46, 70 Timepieces, Chaldean, xvi, 58; civilization and, v, 57; historical development, 58-65 Time-rate, iv, 383 Timocharis, ii, 28-9, 31 Tin, viii, 161; alloys with lead, melting point, iv, 161-2; atomic weight and symbol, viii, 383; affinity strength, 128; extraction from ores, 271; fusibility, 384; in heavy metal group, 126-7, 154; melting point and requirements, iv, 162; positiveness, vi, 59; production and uses, iii, 368-9; specific gravity, viii, 384; tests for, 287, 288; uses, viii, 161 Tin Plating, viii, 273 Tinstone, viii, 161 Tint, of colors, xi, 90 Tips, of plants, xiii, 111, 114 Tire Pumps, heat of, v, 351 Tires, iron, on wagon wheels, iv, 4, 134-5; pneumatic and other, v, 133-4 Tissue Fluids, ix, 50; abundance in connective tissues, 59; constituents, 173-81, 189-90; oxygen supply, 253, 254, 260; renewal and supply system, 51 (fig.), 191, 193-5; waste products removal, 221-2, 262 Tissues, amino acids in, ix, 284, x, 204, 277-8; blood acidity neutralized by, 280, 281; carbon dioxide, production and removal, ix, 262, 264; chemical composition, viii, 298, 348, 354, 355; colloidal condition, viii, 356; connective (see Connective Tissues); diseased, composition and X-ray treatment, vii, 253, 255-6; electricity effects, 247; energy sources, ix, 289, 290, 291, 297; growth of various kinds, 47-8, 286-7; infections of, x, 204; "irritability" theory of, 86; oxygen needs and supply, ix, 253, 260, 261-2, x, 331, 338; protection against germs, 201; protein needs, viii, 359, ix, 278-84, 287-9, x, 204, 277-8; resistance to germs, 197-8; spaces for fluid, ix, 50; wastage, normal, 281-3; wastage in starvation, 297-8; waste removal, 271; water in, viii, 39 (see also Body Cells, Protoplasm) Titan, moon of Saturn, ii, 249-50 "Titanic," loss of, xi, 332 Titanium, symbol and atomic weight, viii, 383 Titchener, Prof. on imagination, xi, 225; on skin, 114; on reaction types, 155 Titicaca, Lake, xiv, 205 Tivoli, Italy, travertine deposits, xiv, 146; waters of, 147 Tjemoro Tree, xiii, 15 TNT (see Trinitrotoluol) Toads, xii, 169, 174-7; evolution of, 167; rains of, 177 Toadstools, xiii, 164 Toasts, origin of, xv, 363 Tobacco, xiii, 256-9; American origin, 221; xiv, 382; historical importance, xiii, 208; hyperacidity of stomach caused by, x, 322; ripened by bacteria, 194 Tobacco Leaf, X-ray sterilization, vii, 257 Todd, Prof. David, author ASTRONOMY TODAY, Vol. ii. Toddy, flowering of, xiii, 53 Toes, bones of, ix, 69; rising on, muscle used, 76; of infants, xv, 61; use of, by apes and men, 60, 61 Toilet Soap, viii, 142 Toledan Tables, ii, 38, 39 Toledo, blades of, v, 315; conquest of, effects, x, 37 Toluene, derivatives, viii, 238-9; from coal tar, 253 Toluidine, viii, 237 Toluol, viii, 235 Tom, Mount, iii, 212, xiv, 111 Tomahawks, xv, 208 Tomatoes, adventitious roots, xiii, 19-20; berries, 54; calories in, ix, 299; food value, viii, 365, ix, 30; origin, xiii, 221, 224, xiv, 382; splitting of, xiii, 94 Tomato Tree, origin, xiii, 227 Tomboro, dust from eruption, i, 59, 360 Tommasi, Crudeli, x, 155 Ton, unit of weight, iv, 283-4 Tonal Fusion, xi, 106 Tones, musical, iv, 207, xi, 105-6; number in Indian scale, xv, 314; pitch and intervals, ix, 99-100; qualities of, xi, 104, 105; simple and compound, iv, 213-17; vibration rates, iv, 204 Tongue, functions in voice production, ix, 83; muscles of, 77, 83; nerve connections, xi, 76; of chameleons, xii, 209; of serpents, 211-12; of toads and frogs, 174; papillæ, xi, 70, 71; response to taste, 62; taste buds of, ix, 94, 95; touch organs of, 92 Tonopah District, Nevada, xiv, 126 (fig.) Tonsilitis, rheumatism and, x, 223 Tonsils, infections of, ix, 187, 188, 224; infections through, x, 198, 202, 219, 220, 221, 223-4, 225; lymph nodes, ix, 224; removal of, 224 Tool-making Animals, v, 9-19 Tools, adjustment to workmen, xi, 362; antiquity of hand, v, 42; early use of, iv, 24; historical development, v, 12-16; machine, 42-56; of ancient Egypt, xvi, 67; pneumatic, i, 27-8, iv, 129; resemblance to hand, xi, 44-5; stone, evolution of, xv, 102-10; use by man and animals, v, 9-11, ix, 67-8 Tool Steel, v, 55 Toothache, hypnotic treatment, xi, 315 Top Shells (Trochus), xii, 71-2 Topaz, iii, 340; oriental, 327 Topography, changes in, xiv, 29-30; changes, how effected, 33-79; fault and joint effects, 114-33; forms determined by rocks, 80-113, 125-6; importance in war, 92-3; of old and new areas, iii, 33-5, 36-7, xiv, 30, 47-9; winds affected by, i, 294, 296-7 (see also Land Surfaces, Relief Features) Tops, as gyroscopes, v, 339 Tornadoes, i, 137-8, 383; cores, 299; devices to dispel, 335-6; electrification by, vii, 212-13; lifting power, i, 356; miscalled cyclones, xiv, 349 Tornado Insurance, i, 269 Torpedo Fish, vi, 16, xii, 149-50 Torpedoes, from aeroplanes, v, 375; submarine, 340, 373-4 Torque, defined, iv, 384; of motors, 309, vi, 224-7, 232, 234; in induction motors, 24 5, 247-8 Torricelli, barometer invention, i, 68, iv, 29-30, 114, 121 (fig.), xvi, 109, 177; scientific work, 104, 109-10, 111 Torsion Balance, invention, vi, 17-18 Torsion Pendulum, v, 74 Tortoises, xii, 182, 185-94 Tortoise Shell, xii, 185-6; commercial source, 193 Totalizers, i, 118, 383 Touch (sense), ix, 91-2, 314, xi, 109-11, 114-15; arrival platform for, ix, 146; development of, xi, 43; in fishes, xii, 137; in infants, ix, 349; in men and apes, xv, 60; quality differences, to what due, xi, 164-5; space perception by, 163, 164-6, 184 Touch Blends, xi, 127-8 Touch-me-nots, xiii, 56 Toul-Verdun Line, France, xiv, 90-1 Tourmaline, iii, 340; light polarization by, iv, 354 Tours, cave dwellings near, xv, 266 Toxins, x, 196, 197, 296, 299 Trachea (windpipe), as infection center, x, 220 Tracheata, xii, 81 Trachoma, racial susceptibility to, xv, 51 Traction, of locomotives, v, 207; Electric (see Electric Traction) Tractors, motor, v, 214, 215-18, 243; of airplanes, iv, 34 Trade Marks, psychology of, xi, 348 Trade Winds, i, 127, 383, xiv, 348-9; Columbus and the, i, 128-9; deflection by earth's rotation, xiv, 32, 348; dryness of, 355-6; in Mediterranean lands, 358; "pulse of atmosphere," i, 218; salinity of sea affected by, xiv, 296; variations and depth, i, 130 Traditions, crowd psychology in, xi, 333 Trailing Arbutus, xiii, 202, 351 Training, continuity of, xi, 257 Train Sickness, cause, xi, 127 Traits, hereditary, ix, 328-9 (see also Characteristics) Trances, Hindoo belief regarding, ix, 11-12, 17, 266-7; primitive conception of, xv, 328 Transformation of Energy, vi, 128-9; by muscle cells, ix, 74; by plants, 27; in Wilberforce Spring, iv, 85 Transformers, Current, vii, 44-5 Transformers (Potential), vi, 159-60, 306-29; distinguished from current, vii, 44-5; distribution units, 25-6; efficiency, vi, 317, 317-18, vii, 367; importance of understanding, vi, 9; in electro-therapeutics, vii, 245-6; in power plants, vi, 364, 376-7; in radio generation, vii, 266; in traction systems, 199; voltage possible, 9-10 Transfusion of Blood, x, 337-8 Transits, defined, ii, 189; eye-and-ear observations, xi, 155-6 Translation, energy of, iv, 83-5; motion of, 85-6 Translations, inadequacy of, xv, 146 Translucent Substances, iv, 324 Transmigration of Souls, xv, 333-4; morality and, 356-7 Transmission Gears, hydraulic, v, 105-6 Transmitter, telephone, vii, 93-4, 96 Transmutation of Elements, viii, 188-9 Trans-Neptunian Planet, ii, 270-2 Transparency, of glass, viii, 305 Transparent Substances, iv, 324 Transpiration (plants), xiii, 103, 104, 113, 374, 378, 379, xiv, 377-8, 378-9, 379 Transportation, aerial, i, 39, 41-3, 44-5; civilization and, v, 18; evolution of, 17-18, xv, 13, 241-3; friction in, v, 203, 204-6; meteorology in, i, 267-8; motor trucks, v, 214; river, xiv, 191; wheels, v; legs, v, 214-15 Transportation Problem (U. S.), vii, 194-5 Transvaal, climate conditions, xiv, 224; gold production, iii, 365; law against rain-making, i, 336 Transverse Rivers, xiv, 154; in Appalachians, 167, 168-9 Trapdoor Spiders, xii, 97 Traps, animal, xv, 224 (fig.), 225-7; avoidance of, xv, 66 Trauma, x, 255 Travel, educational advantages, vi, 330 Traveled Soils, xiv, 69-75 Traveler's Tree, xiii, 106, 112 (illus.), 189 Travertine, iii, 325, xiv, 146 Treadmills, xv, 239-40 Tree Corals, xii, 43 Tree Frogs, xii, 176, 177-9; voice of, 170 Tree of Heaven, xiii, 200 Tree Ferns, xiii, 65 Tree Snakes, xii, 221 Trees, ancient, iii, 252, 253-4, 254, 255, 256-7, xiii, 309-10; Big (see Big Trees); branching of, xiii, 85-6; carbon dioxide used by, i, 10; cone-bearing, xiii, 174 (see Conifers); danger in thunderstorms, i, 155; deciduous, xiii, 175; distribution determined by Glacial Epoch, xiv, 375-7; felling of, by Indians, xv, 262; fog drip, i, 351; hardiness of, xiv, 364; landscaping, xiii, 269-72; leaving in forests, xiii, 86-7; marsh-draining by, xiv, 379; moisture required by, 377-9; northern limit of, xiv, 371, 374-5; older than herbs, xiii, 319; paper from fibers, v, 290, 292-5; prairies and, xiii, 374, 375, 376; rainfall and cold in relation to, 373; rate of increase by seeding, xv, 19; rime on, i, 121-2; rings, xiii, 24-5, 26; rings, climate changes seen in, i, 199-200, xiv, 362; rise of water in, xiii, 94; roots, 16-17, 19; roots, power of, iii, 24; shedding of leaves in dry seasons, xiv, 369; species in America and Europe, 375; strangled by vines, xiii, 21-2; stunted, 367; tallest, 94; trunks, structure, 23-6; United States, xiv, 372-4 Trembling, in fear, xi, 132, 133 Tremolite, iii, 321 Trench-digging, competitive test, xi, 363 Trench Fever, x, 202 Trenches, ocean, xiv, 286, 288, 289 Trenching Machines, v, 253, 254-5 Trentino, xiv, 244, 245 Trenton Falls Gorge, iii, 50, 243 Trenton Limestone, iii, 185-6 Trepangs, xii, 50 Trepanning, Hippocrates, methods, xvi, 96 Trephine Operations, x, 27, 79 Trevithic, Richard, v, 207-8, 212, 377 Trial Marriages, xv, 290 Triangles, center of gravity in, iv, 101 Triassic Period, iii, 20, 208-13, 383; animal life of, 271 (fig.), 285, 291; appearance of mammals in, xii, 271; insects of, 104 Tribes, formation of, xv, 363; primitive morality limited to, 374 Tribes, plant, xiii, 171 Tributary Streams and Valleys, xiv, 56-7 Triceratops, iii, 292 Trichina, cause of, xv, 49; parasite of, x, 199, xii, 45 Trieste, Gulf of, springs along, xiv, 150 Trifid Nebula, ii, 355, 364, 365 Trigonometry, history of development, xvi, 54, 62, 92, 101 Trilobites, iii, 260, 276-8 Trinidad Head Lighthouse, storm waves at, xiv, 300 Tri-nitro-phenol, viii, 262 Trinitrotoluene, (T. N. T.) viii, 236, 237, 261-2 Trinitrotoluol, viii, 63; potential energy in, iv, 82 Trinil Man, xv, 89; brain of, 96 Triphenyl Methane, viii, 240 Triple Register, i, 88 Tripoli, intersection of eclipse paths in, ii, 216 Tripolite, iii, 335 Trogons, Mexican, xii, 267 Trojan War, hashish at time of, xiii, 239 Trolley Cars, uses and disadvantages, i, 41 (see Electric Cars, Electric Traction) Trolley Systems, vii, 186-91, 197-200; underground wires in, 11-14 Trombones, iv, 231 Trompe, air compressor, v, 89-91 Tropic Birds, xii, 253 Tropical Diseases, xiv, 356-7; racial immunity to, xv, 48, 50, 51 Tropical Rain Forests, xiii, 357-66, xiv, 366-70; woods and other products of, 383 Tropics, civilization in relation to, xv, 123, 124-7; climate monotony, xiv, 357; cyclones, i, 136; dry and rainy seasons, xiv, 352; frost in, 42; glaciers in, 54; health conditions, i, 327, x, 251, xiv, 356-7; labor in, xv, 126; land and sea breezes, i, 131; man's development in, ix, 308-9; products, remarks on, xiii, 259; quinine use, 251; rainfall, i, 109; rainfall and forests in, xiv, 377; seasonal temperature layer in, 13; soil depths, 64; snow line in, xv, 73; thunderstorms, i, 151; vegetation of, xiv, 366-70; white race in, i, 327, xiv, 344, 356-7, xv, 49-50; winds, i, 127, 135 Troposphere, i, 20, 383; turbulent conditions, 293-6 Trotula, x, 36, 37 Trough (meteorology), x, 238, 384 Troughs, oceanic, xiv, 286, 288-9; earthquakes and, 341 Trough Valleys, xiv, 117-21, 123-4 Trout, xii, 158-9; wariness of, 139 Troy, siege of, plague at, x, 285 Trucks, Motor, v, 214; advantages to farmers, vii, 230-1 Trumpet Creeper, xiii, 20 Trumpets, sounding of, iv, 231 Trunk (body), muscles of, ix, 77; skeleton of, 64-7, 63 (fig.) Trunk-bearing Animals, evolution, iii, 300, xii, 302 Trunks, tree, structure, xiii, 23-6 Truth, experience as test of, (Sylvius), x, 69; men's notion of, xi, 243; scientist's search, vi, 107 Trypanosomiasis, x, 167-79 Trypsin, x, 326 Tryptophane, viii, 351 Tsetse Flies, x, 168-70, xiv, 197, 223 Tuatera, xii, 183-4 Tubercle Bacillus, discovery of, x, 149; killed by sunshine, 292; tissue-killing power, 293 Tubercles (lesions), x, 293; of plants, xiii, 98 Tubercular Lesions, x, 293; radiation treatment of, 384 Tuberculin, x, 150, 216 Tuberculin Test, x, 372 Tuberculosis, x, 289-94; campaign against, 171, 172, 175-6, (France), 290-2; climatic treatment, i, 331; contraction of, from consumptives, i, 326, x, 293; darkness and, 253, 290, 291; diagnosis, 216-17, 372; discovery of bacillus of, 149, xvi, 184; diseases leading to, x, 292; Galen's studies of, 30; germ of, 195, 292; immunity to, 207; in warm and cold-blooded animals, 206; Koch's studies of, 149-50, xvi, 184; local infections, x, 293; lowered blood pressure in, 336; outdoor treatment, 240-1, 291; pain of, xi, 118; portal of entry of germ, 198; predisposition inherited, 235; racial susceptibility to, xv, 49, 50, 51; spinal, x, 92 Tubers, xiii, 23, 24 (fig.), 218 Tuileries, invasion (1848), xi, 331 Tulips, in lily family, xiii, 184 Tulip Tree, xiii, 271-2, 318 Tumbleweeds, seed dispersal, xiii, 345 Tumors, radiation treatment of, x, 383 Tundra Vegetation, xiii, 381 Tungsten, in steel alloys, xiv, 238; symbol and atomic weight, viii, 383 Tungsten Lamps, vi, 267, 268; candle power, iv, 352; due to Acheson, vii, 300 Tunicates, xii, 19-20, 129 Tuning Forks, record of, iv, 214-15 (fig.); reenforcement and interferences of sounds, 219, 220-1; resonance columns and, 227-8; sound production by, 197; synchronous vibration, vii, 118; vibrations of, iv, 224 Tunneling Machines, iv, 122-4, 260-1 Tunnels, compressed air use in, iv, 129; heat encountered in building, iii, 121, xiv, 13-14; hot water encountered, xiv, 144; sounds of trains in, iv, 236 Tuns (shells), xii, 73-4 Tupaias, xii, 367 Turbans (shellfish), xii, 71-2 Turbinates, of nose, x, 341 Turbines (see Steam Turbines, Water Turbines) Turf, xiii, 183 Turf Grasses, xiii, 181 Turgenev, Ivan, brain weight, xv, 39 Turgor of Leaves, xiii, 102, 103, 114 Turin, position toward Alps passes, xiv, 240 Turkestan, wild horses of, xii, 307 Turkey, coverings of women in, xv, 254; opium in, viii, 253; tobacco production, 258 Turkey Buzzards, xii, 260 Turkeys, xii, 261 Turkish Empire, extent of conquests, xiv, 308-9 Turks, invasion of, through Danube Valley, xv, 138; migration and conquests of, xiv, 308-9, 311 Turner, astronomer, ii, 301, 343; on Halley, 86 Turning Effort (see Torque) Turnip, family and origin, xiii, 197, 224; swelled root, 19; vitamines in, x, 262, 266, 268 Turpentine, chemistry of, viii, 51, 240; in medicine, Galen's use of, x, 30; specific gravity of, iv, 109-10 Turquois, iii, 340-1 Turret Lathes, v, 52-3 Turtles, xii, 182, 185-94; absence of fear, xi, 136; egg-teeth of, xii, 205; heart of, ix, 84; Mesozoic, iii, 295; regeneration in, xii, 170; shell of, xv, 18; under-shield of, xii, 184 Tuscarora Deep, xiv, 341 Tusks, evolution, iii, 300, xii, 302; of walruses, 335 Tusk Shells, xii, 58, 74 Twentieth Century Science, xvi, 195-8 Twilight, i, 167, 384; duration, 18 Twine Binders, v, 247-8, 381 Twinleaf, distribution, xiii, 351 Twins, identical and nonidentical, ix, 44, 327, xv, 27 Twisters, Texas, i, 60, 384 Two-phase, defined, vi, 203-4, 242 Tycho Brahe, ii, 14, 45-8, iv, 95, xvi, 102; as astrologer, ii, 21; eclipse of 1560 and, 210; new star seen by, 12, 331; Kepler and, 49, 50; star catalogue of, 300-1 Tylor, Prof. E. B., "Anthropology" of, xv, 4; on English spelling, 177 Tyndall, fog signal studies, i, 189, 190 Tyndall Effect, viii, 315 Type, invention, v, 300; movable, Chinese, xv, 179 Typesetting Machines, v, 307-12 Typewriters, development, v, 312-13, 380, 381; to take spoken words, 331; used in telegraphy, vii, 112-13 Typhoid Fever, x, 286-88; consumption from, 292; death rate, viii, 321-2, x, 286, 288; discovery of germ, xvi, 185; feeding in, ix, 319; from water pollution, xiv, 140; germ, x, 194, 287-8; germs destroyed by chlorine, viii, 86; germ diagnosis, x, 215, 216; immunity to, 205, 207; inoculation against, 208, 217; named by P. C. A. Louis, 108; portal of entry of, 198; prevention of, 171, xv, 49; water pollution and, viii, 318-19, 321-2; wells and, iii, 121 Typhoons, i, 136, 384; locating of, 279-80; signals (China), 283 Tyrannosaurs, iii, 290 Tyrian Dye, xii, 72 Tyrol, hail crosses, i, 341; lakes of, xiv, 200 Tyrrhenian Basin, xiv, 291 U-boats, motors used, vi, 239 Uganda, sleeping sickness in, xiv, 223 Uinta Mts., xiv, 83, 98, 226-7, 229; fault scarp of, 230; little metamorphism in, 234; no igneous intrusions in, 228, 230; river canyons of, 83, 166 Ulcerated Teeth, electric treatment, vii, 237 Ulloa, Admiral, astronomical studies, ii, 179, 221 Ulloca's Rings, i, 184, 384 Ultramicroscopic Organisms, x, 200 Ultraviolet Rays, iv, 358 (fig.); absorption in upper air, i, 16; actinic effects, iv, 365-6, vii, 250; effects on barium, 254; frequency of vibration, 260; in therapeutics, 253; fluorescence from, iv, 379; luminosity of objects in, 378; ozone produced by, i, 16; radiant energy of, iv, 366; transmitted by æther, vi, 119, 269; use of, in medicine, iv, 51; wave lengths of, 365, 366 Ulugh Begh, ii, 39, 300 Umbel, flower form, xiii, 50, 200 Umbra, of shadows, iv, 332 Umbrella Type Generators, vi, 362 Unclean Diseases, Jewish laws on, x, 15 Uncleanliness, air poisoning by, ix, 270, 352; diseases from, x, 290, 311; plagues due to, xv, 49 Uncompahgre River, iv, 172, 173 Unconformities (geology) defined, iii, 171, 383; oldest known, 175; what they represent, 176 Unconscious Actions, xi, 27; from habit, 254-5 Unconscious Mind, xi, 47; in reasoning, 245-6 (see also Subconscious Mind) Unconsciousness, from excessive breathing, ix, 266-7 Undamped Waves, vii, 273, 289-90, 291 Underclothing, proper materials, x, 307, 308; soiled, injuriousness of, 310 Underfeeding, results, xi, 370 Underground Streams, iii, 116, xiv, 149-50; springs and, iii, 117 Underground Transmission, vii, 11-14, 24-31; in telephone systems, 104, 105 Underground Trolley System, vii, 187, 189 (see also Third Rail) Underground Water (see Ground Water) Undermining, of rocks, xiv, 131 Undernutrition, due to under-chewing, ix, 228 Undershot Wheels, v, 76 Underwriters, National Board of Fire, vii, 53-4 Underwriters' Code, vii, 54, 57, 58, 61, 62 Unfit, Survival of, xv, 27 Unger, xvi, 166, 167 Ungulata, xii, 300-31 Unicellular Plants and Animals, xii, 10, xii, 166, 167; composition and life, ix, 48-9; food needs of, 33; food procuring by, 12-15, 19; motions of, 73, 74; perception of light and shade by, 105 (see also Protozoa) Unicorn Plant, fruit, xiii, 57 (fig.); seed dispersal, 343 Union Pacific Railway, Rocky Mountain pass of, xiv, 76 Unions, chemical, viii, 20-1 United States, aerial mail service, i, 44; animals (carnivorous), xii, 337, 340, 342, 349, 350, 363, 365; Atlantic coast, xiv, 25, 45, 246-7, 249-50, (see also Atlantic Coastal Plain); Atlantic coast rivers, 167; automobile industry, v, 213-14; bats of, xii, 371; beet sugar production, xiii, 216; birds of, xii, 254-69; bison of, 329; brontides, i, 196; bubonic plague measures, x, 164; buildings overheated, i, 323; building stones, iii, 371-2; coal and coal beds, 343, 345-8; coal supply, v, 172; coffee consumption, xiii, 232; corn crops, critical period, i, 248; cotton production, early, v, 270; crop forecasts, i, 251; dark days, 56-7; deer species in, xii, 317-18, 322; deserts of, xiv, 380; dust deposits, i, 54-5; dust in west, xiii, 344; English sparrow in, xv, 21; fire losses in rural districts, vii, 231; first locomotive, v, 378, 378-9; fish of, xii, 151-64; flies of, 120; food and vitamine question, x, 267-8; forests, xiii, 366-73, xiv, 239, 372-4; forests, national, xiii, 371-2, xiv, 239; forest fires, i, 48-9, 56-7; fresh-water mussels of, xii, 65-6; frogs of, 180, 181; geological works on, xiv, 171; glacial topography in northeast, 60-2, 170-1; gypsum production, iii, 376; hailstorm insurance, i, 344-5; high temperature record, i, 209; history in relation to physiography, xiv, 61-2, 191-5, 242-3, 249-50, xv, 136; Indian summers, i, 361; influenza pandemics, x, 294-5; iron and steel industries, xvi, 175; jute production, xiii, 243; land leveling rate, iii, 31-2; land policy, xiv, 384; lava plateau of northwest, 104, 164, 170, 172, 188 (see Columbia Plateau); lengthened life in, x, 291; lightning losses, i, 156; lizards of, xii, 207, 208; loess deposits, xiv, 72; medical practice, history of, x, 104, 115-16, 121-5, xvi, 185-6; medical schools, xvi, 181; metal products, iii, 356-70; meteorological organization, i, 212-13, 215-17, 221, 222; mineral springs, xiv, 143-4, 145; newts of, xii, 172; opossums of, 275; ore deposits, monographs on, xvi, 173; oyster industry, xii, 61, 62; Pacific coast (see Pacific Coast); paper-making, v, 292; pellagra in, x, 265, 268; petroleum and natural gas, iii, 349-51, 353, 354, 355, v, 172-3; phenological observations, i, 254-5; plains, coastal and interior, xiv, 213-15; potash sources, viii, 279; power plants, viii, 74-5; prairies, xiii, 373, 374, xiv, 380, 383; public health fellowships, x, 172; rainfall i, 110, 110-11, 112, xiv, 352, 360, iii, 113; rodents of, xii, 288, 290, 293-6; salt deposits, iii, 374-5; scurvy in, x, 266; seasonal advance rate, i, 256; smoke costs, 64; snails of, xii, 71; snakes of, 218-25, 232-8; snowfall, heaviest, i, 118-19; specialization of different parts, xv, 131-2, 203; standard units used in, iv, 45-6, 69; summer of 1816, i, 359-61; tea consumption, xiii, 231; telegraph system, vii, 107-8; thermometer scale used in, iv, 136; thunderstorms, vii, 218; toads of, xii, 176; tobacco production, xiii, 256, 257, 258, 259; transportation problem, vii, 194-5; tuberculosis in, x, 290, xv, 49; turtles of, xii, 189, 190, 191; typhoid fever, viii, 322, x, 286; volcano, only active, iii, 103; water consumption, viii, 324-5; water filtering in, 319, 320; water power, v, 83-4; water supply by wells, iii, 118; weather prophets, i, 243; weeds, xiii, 353-4; western plateaus, xiv, 220; western rivers and lakes, 188; wheat cultivation, xiii, 211; windmills, i, 37-8; winds, 128, 133-4; World War chemical and medical services, x, 176-83, 186, 187-8; World War disabled, care of, 189-91; yellow fever extermination, 162 U. S. Army, chemical warfare service, x, 187-8; medical corps in World War, 177-83, 186, 187; yellow fever campaign, 159, 160-2 United States Bureau of Fisheries, xii, 155 U. S. Bureau of Standards, aeronautical research, i, 51; lightning statistics, 156-7 United States Forest Service, xiii, 371-2; aeroplanes in, i, 48-9 U. S. Hydrographic Office, i, 273, 277 United States Navy, cold-air machines, v, 353; electricity on ships, vii, 326-35; meteorological unit, i, 311; ocean surveys of, xiv, 283; radio control of ships, vii, 284 U. S. Public Health Service, x, 162, 164, 175 U. S. Signal Service, i, 282-3; meteorological observations, 216, 220 U. S. Weather Bureau, agricultural service, i, 252, 256-7; bulletin on temperature and foods, 268; cloud pictures, 103; code, 234; establishment, 216; fog classification, 95; forecasts of various kinds, 239-40, 242; frost predictions, 260; functions, 7-8; kiosks, 267; library, 268-9; marine division, 273, 275-6, 281; organization, 222; question answering, 359; snow surveys, 118; Spanish war services, 309; storm predictions, vii, 218; sunshine recorder, i, 86-7; term hours, 203; terms used, 107, 108, 136; thermometers, 74, 75; tide predicting machines, v, 327; triple registers, i, 87-8; vanes used, 82; weather maps, 228, 230, 232-7; wind-aloft maps, 230, 231, 233; wireless reports, 280 Units, iv, 384; absolute and gravitational, 64-5; atmospheric pressure, 121, 123; electrical, 261, 284-5; heat, 154; magnetic force, 249; power, 80; work and energy, 79-80 (see also Weights and Measures) Universal Ether (see Æther) Universal Soul, or pneuma, x, 27, 29 Universe, electricity the basis, vi, 107-8, 113, 118; elements, 108-9; energy of, unchanging, iv, 40; evolution, ii, 366-84; geocentric conception, ii, 9-10, 34-5; Greek theories, xvi, 76-7, 77-9, 80, 81-2, 84, 186; magnetism pervading, vi, 40; primary concepts, iv, 14-15; shape of visible, ii, 352-3; stellar, 294-9; total available heat of, iv, 193 Universities, founding of European, x, 38, xvi, 100; revival of learning through, ii, 11-12 University of Pennsylvania, park in grounds, xi, 188 Unknown, uneasiness in face of, xi, 224, 225 Unsaturated, defined, viii, 382 Unsaturated Paraffins, viii, 230-2 Upper Air, composition, i, 10-11, 16; exploration, 18-19, 20-3; rarity, 17; sun corpuscles in, 144, 146, 158, 159, 160; temperatures, 19, 20 (see also Stratosphere) Ural Mountains, antiquity of, xiv, 96 Uraniborg Observatory, ii, 45, xvi, 102 Uranium, atomic number, viii, 183, 309; radioactivity, 184, 185, 186; symbol and atomic weight, 383 Uranus, atmosphere, ii, 250; comet families, 271; discovery, 15, 104, 254, 255, 267, 272; habitability, 250; Neptune and, 268-9, 270; orbital deviations, 67, 79, 271; photographic study, 183; rotation period, 377; satellites, 105, 268; size and orbit, 162-3; weight, 76, 77 Ure, chemist, xvi, 163 Urea, artificial production, xvi, 142, x, 279, 329; composition and amount, 342; composition and functions, viii, 230, 353-4; in amine group, 215; production and disposal of, x, 279, 329, ix, 284, 285 Uremia, x, 346 Ureter, ix, 273 Uric Acid, viii, 230, 354, x, 342-3 Urinalysis, x, 378 Urinary Tract, as Infection center, x, 220 Urine, acidity and alkalinity of, x, 281; albumen in, 378; amount and excretion, 379; amount, on what dependent, ix, 274-5; constituents and disorders of, x, 342-6; Corbeil's work on, 37; formation stages, ix, 273; nitrogen in, 282; salt in, 273; sugar in, 291, 292-4; urea in, 284; waste products in, x, 270 Urochords, xii, 129 Urodela, xii, 169, 170-3 Ursa Major, changes in, ii, 306; spiral nebulæ, 363-4; system, 122, 343, 344 Utah, arid topography of, xiv, 42; bad lands, 82; cliff topography, 88; mining products, iii, 360, 361-2, 362, 363, 368; plateaus, xiv, 220, 222; subsidence, iii, 152; Uinta Mountains, xiv, 83; volcanic fields of, 317, 318 Uteroplacental Circulation, discovery of, x, 94 Vaccination, discovery, x, 100-3, 207-8, xvi, 127; present extent, x, 103; success of, 217, 288 Vaccines, autogenous, x, 218; in focal infection diseases, 226 Vaccinia, x, 100 Vacuum Balloons, v, 222-3 Vacuum Cleaner, iv, 127, v, 137, vii, 83-4; atmospheric pressure in, i, 25; for barn uses, vii, 228 Vacuum Machine, iv, 127 Vacuum Refrigerating Machines, v, 354-6 Vacuums, boiling point of water in, v, 354; detonation from filling, vii, 211; early attempts to obtain, iv, 29-30; electrical nonconductors, 259; electric discharges in, 317-18; falling bodies in, 97; Gessler's and Crookes's x, 183-4; heat, v, 345-58; high, iv, 127, vii, 376; nature's abhorrence of, iv, 27, 114; of steam condensers, vi, 355; Pascal's studies, xvi, 110; sound in, i, 186, iv, 195 Vacuum Tube Generators, vii, 274, 276-8, 291 Vacuum Tube Receivers, vii, 270, 278-80 Vacuum Tube Rectifiers, vi, 339-41 Vacuum Tube Repeaters, vi, 125 Vacuum Tubes, cathode rays in, iv, 317; Gessler's, x, 183-4; use in wireless service, vi, 125, 339-41, vii, 277-80 (see also Crookes Tube, Coolidge Tube) Vagus Nerve, xi, 30 Vail, Theodore N., vi, 87 Valence (chemistry), viii, 93-4, 382; in periodic classification, 178, 180-1, 179-80; ionization and, 122; table of, vii, 384; variable, viii, 94, 179, 189; variable in catalyzers, 102; zero, 178, 181 Valeric Acid, viii, 220 Valley Breezes, i, 131, 132, 377 Valley Glaciers, iii, 60, 62-3, 67 Valleys, air currents, i, 294 (fig.), 296; drowned (see Drowned Valleys); fault-made, xiv, 117-21, 127-8; glacial, iii, 64, 66, xiv, 56-8, 259-60; hanging, iii, 65, xiv, 57; historical importance of, xv, 138-9; longitudinal in folded strata, xiv, 93, 94-6, 98, 226, 229; people of, xv, 122; rift or trough, xiv, 117-21, 123; river (see River Valleys) Valley Trains, iii, 68 Valliere River, tributary changes, xiv, 184 Valparaiso, harbor of, xiv, 265 Valve Gears, inventions, v, 379 Valves, of heart, ix, 204; leaking, 206-7 Valvular Heart Disease, x, 332 Vampires, xii, 369, 371-2 Vanadium, use and occurrence, xiv, 238; symbol and atomic weight, viii, 383 Van Deventer, obstetrician, x, 80 Van Drebel, Cornelius, v, 196 Vanes, wind, i, 82, 384 Vanessas, xii, 117 Van Helmont, Jean Baptiste, x, 67-9, 71, xvi, 108, 110, 111, 119, 163; recipe for creation of mice, x, 139 Van Hise, geological work, xvi, 172-3, 174 Vanilla, xiii, 259-60; chemical composition, viii, 239, 251 Vanity, clothes due to, xv, 253, 255; impulse of, 185 Van Maanan, astronomer, ii, 153, 314, 363 Van Swieten, x, 77, 104 Van't Hoff, xvi, 164 Vapor Baths, temperature of, x, 251 Vapor Pressure, iv, 167-8, viii, 303-5 Vaporization, latent heat of, iv, 173-4 Vapors, condensation of, viii, 304 Variable Stars, ii, 324-30; collision theory, 327, 329, 333; color, 296; discoveries by Bailey, 146; in star clusters, 337, 338; inception of study, 16; sun, 171, 187 Variability, in living things, xiii, 326-7 (see Variation); meteorological, i, 384 Variation (biological), xiii, 326-36, xv, 22-3, xvi, 151; causes and perpetuation, ix, 327, 328-9, xvi, 153; in human beings, xv, 27; in plants, xiii, 326-36; meristic and substantive, xvi, 155; new species developed from, xv, 24-5; principles understood in Egypt, xvi, 72; selection and perpetuation, xvi, 154-5 Varieties, crossing of, results, ix, 333-4, x, 231, xiii, 332-3; defined, 329-30; mixture, 147; origin, 326-35 Variola (smallpox), x, 100 Varney, B. M., i, 296 Varnishes, ancient knowledge of, viii, 269; chemistry of, 264-6; drying oils in, 245, 247 Varro, on weather vanes, i, 68 Varus, defeat of, i, 307 Vascular Cryptograms, alternation of generations, xvi, 166 Vascular System, xiii, 65-6; not in mosses, 69; first appearance, 303, 304, 306 Vasoconstrictor Center, ix, 215-19 Vasodilator Center, ix, 219-21 Vasomotor Center, ix, 215 Vasomotor System, efficiency, how developed, x, 238-9, 240, 241; heat loss, regulation by, ix, 311 Vassenius, astronomer, ii, 179 "Vaterland," steamship, v, 193 Vaughn, on anaphylaxis, x, 214 Vedas, song to day-god, ii, 23-4; weather proverbs in, i, 67 Veery, xii, 269 Vega, Arabic name, ii, 39, 302; color, 297; Sirian star, 115; spectrum, 116 Vegetable Acids, viii, 222-3 Vegetable Fats, viii, 244, 246; vitamines absent in, 369, ix, 33, x, 259, 260-1, 262 Vegetable Kingdom, chemistry of, viii, 191; food source of man, ix, 24; how distinguished, xii, 14-15, xiii, 13-14; relation to animals, viii, 334 (see also Plants) Vegetable Oils, composition and energy value, ix, 28 Vegetables, calory loss in preparing, ix, 299; cooking of, effects, viii, 368; food value, 365, ix, 34, 280, 300, x, 259, 260, 262, 266, 273, 279; freezing prevention, iv, 161; frost danger point, i, 258; green bile from eating of, ix, 275; origin of common, xiii, 221-4, xiv, 382 Vegetable Sheep Plant, xiii, 379 Vegetable Silk, viii, 255-6 Vegetarianism, protein supplies in, ix, 280; remarks on, 285 Vegetation, defined, xiv, 363; determined by climate, and soil, 363-81; effect of light and darkness on, xiii, 84-90; effect on winds, i, 292-3; electrical stimulation, vii, 351-3; growth in tropical forests, xiii, 358-9, 360, 364-5; optimal temperature, xi, 51; past and present, xiii, 174, 175; phosphorescence of decaying, i, 346; soil and rock protection by, xiv, 42; types on what dependent, xiii, 12 Vegetative Nervous System, x, 352-3 Vehicles, evolution of, v, 17 Veins, of body, ix, 191, 195, 197-8; of body, bleeding from, x, 39; blood in, carbon dioxide content, ix, 263, 264; blood in, color of, 260-1; functions in circulation of blood, x, 63-65, 334; connections with arteries, ix, 192-3 (fig.) 197; valves of, 222; of leaves, xiii, 32-3, 37 (fig.), 79 Veins, Mineral, defined, iii, 383-4; how formed, 126 Velocity, iv, 56-7, 384; acceleration of, 57 (see Acceleration); energy from, 78; momentum and, 62-3; Newton's laws and high, ii, 80, 81; of falling bodies, iv, 65; relation to power in machines, 92; required on centrifugal railroads, 74; unity of, 64 Velpeau, x, 130 Vena Cava, ix, 197-8, 201 (fig.), x, 334; waste fluids emptied into, ix, 222 Vena Contracta, v, 89-90 Venereal Diseases, contagion demonstrated by Saliceto, x, 39; quacks and, 76 Venice, commercial growth and decline, xiv, 308 Venomous Snakes, xii, 224-38 Ventilation, i, 321-2, viii, 331-2, ix, 267-70, x, 237-8; air moving systems, i, 323; electrical, on battleships, vii, 330-1; katathermometer in, i, 320; importance of, to infants, ix, 352; ozone, vii, 353-4; perception of need of, ix, 97 Ventral Segments, of vibrations, iv, 217 Ventricles, of brain, xi, 29 Ventricles, of heart, 201 (fig.), ix, 203, 204-5 Venus (planet), ii, 190-2; atmosphere, 130-1, 191, 192, 246; life on, 246-7; lucid planet, 264; non-rotation theory, 377; orbit, 50, 162, 163; phases of, xvi, 103; phases, discovery of, ii, 54, 83, 94; size, 162, 163; stellar magnitude, 296; transits, 58, 129; weight, 76, 77 Venus's Flower Basket, xii, 31 Venus's Flytrap, xiii, 40-1, 64 (illus.) Vera Cruz, harbor of, xiv, 266 Verbal Images, xi, 222 Verdant Zones, i, 259, 384 Verdun, defense of, xiv, 90-1 Verkhoyansk, Siberia, i, 209-10 Vermilion, viii, 170 Vermont, marble production, iii, 189, 371; summer of 1816, i, 360 Verne, Jules, novel by, i, 170 Verrazano, voyage of, xiv, 310 Vertebrae, of spine, ix, 64, 65 (fig.); origin from coelom, xii, 87 Vertebrates, xii, 127-9; characteristics of, 132; classification, iii, 260; evolution, 287 (chart), xii, 167; geological history, iii, 281-306; reproduction in, xv, 54; resemblances among, 55-6; structure and organs of, 55-6 Vertical Distances, xi, 185 Verworn, Dr. Max, quoted, xi, 67 Vesalius, Andreas, x, 46, 50-3, 65 Vesico-vaginal Fistula, x, 122 Vesta (planet), ii, 255, 257 Vestal Virgins, cult of, viii, 89; fire of, xv, 234 Vestibule, of head, ix, 90 Vesuvius, Mount, cone of, xiv, 100, 225; eruptions of, iii, 99-100, xiv, 313, 326, 338; flashing arcs, i, 194; material ejected, xiv, 326-7; only active European volcano, 316; soils and vegetation, viii, 339; soils on, xiv, 329 Vetches, in pea family, xiii, 198; leaves, 113; used in soil enrichment, 98 Veterans of World War, care of, x, 189-91 Vibration, Vibrating Bodies, iv, 86-8, 196; amplitude of, 211; elasticity and, 156; frequency defined, 205, 382; interferences of, 218-22; of elastic bodies, ix, 98-9, 100-1; of rods, iv, 213-15, 223-4; of strings, 216-17, 223; period of, 196, 205, 383; rate of, on what dependent, 213, 223; sound production by, 195-6; sympathetic, 225-6, vii, 118, 261-2; transverse and longitudinal, iv, 215 (see also Waves) Vibrators, electric, vii, 87 Vibgyor, i, 165 Vichy Springs, xiv, 145 Vickers-Vimy Bomber, v, 233 Vicksburg, capture of, xiv, 194 Victoria Falls, iii, 49, xiv, 131-2; forests at, 369-70 Victoria Nyanza, xiv, 120, 204 Vicuñas, xii, 313 Vienna, siege of, xiv, 308-9 Vienna Meteorological Congress, i, 219, 220 Vigo, Juan del, x, 155 Vikings, history of, xiv, 261 Vilmorin, work on sugar beet, xiii, 216 Vincent, George E., x, 175 Vinci, Leonardo da (see Leonardo da Vinci) Vinegar, acetic acid in, vi, 111, viii, 220, 293; from cider, 219; in preserving, 372; production of, 248, 249 Vines, nature and methods, xiii, 27-8; tendrils, 111-12; of tropical forests, 361-2 Vineyards, and hailstorms, i, 343 Vinland, xiv, 261 Violence, and will, xi, 264 Violet (color), complementary color of, iv, 367; primary color, 366; vibration rate, ix, 115; wave lengths, i, 165, iv, 360 Violet Light, fluorescence from, iv, 379; of mercury arc lamp, 282, 283; use of, in medicine, 51 Violet Ray Machine, x, 183-4 Violets, dogtooth, xiii, 184; fertilization, 120; seed dispersal, 56, 339; stemless, 15 Violin, intervals on, iv, 208; resonance chamber, 223 Violin-Piano, vi, 97 Vipers, xii, 229-32; ancestry of, 225; hedgehogs and, 367 Virchow, x, 128-9; "Cellular Pathology," xvi, 182; founder of cellular pathology, x, 119; malaria studies, 156-7 Vireos, xii, 268 Virginia, former volcanoes of, xiv, 318; mineral springs of, 143; rainfall, i, 338 Virginia Creeper, xiii, 28 Virility, from cross breeding, xiii, 120, 122-3 Viruses, attenuating principle, x, 141, 142, 143; filterable, 141, 161 Viscachas, xii, 289; acquisitiveness of, 292-3; prey of boas, 215 Viscera, emotion effects, xi, 134-5; insensible to pain, 118 Visceral Senses, xi, 63-4 Vishnu's Temple, Grand Canyon, xiv, 84 Visibility, i, 384; in aviation, 303; scale, 314 Vision, (sense) xi, 83-97; compared with hearing, 98; defects of, ix, 112-14; distance of distinct, iv, 342, 343; limits (wave lengths), 360, 361; motions connected with, ix, 82; operation, vi, 271-3; persistency of, iv, 346-7, v, 329, vi, 155 (see also Sight) Vis Plastica, iii, 14 Visual Hallucinations, x, 358, xi, 91 Visual Purple, of retina, xi, 96 Vital Capacity, defined, x, 339 Vital Function, tests of, x, 376-9 Vitality, of infants, ix, 352 Vital Knot, ix, 257 Vital Processes, chemical nature of, viii, 353, 355, ix, 34; chemical control of, 167-72; control of breathing, 256-7; functional metabolism of, 295-6; no energy consumed in, viii, 367; past theories of, x, 69, 76-7, 84, 85, 86 Vitamines, viii, 362, 369-70, ix, 33-4, 35-6, 347, x, 256-68 Vitreous Electricity, iv, 258 Vitruvius, work on architecture, xvi, 98 Vividness, in associations, xi, 205 Vlacq, Adrian, xvi, 104 Vladivostok, harbor of, xiv, 267 Vocal Cords, ix, 83 Vocal Organs (see Speech Organs) Vocations, avocations and, xi, 375-7; choice, 276, 358-61 Vocational Guidance, xi, 358-61 Vocational Training, of veterans, x, 190 Voice, evolution of, in amphibians, xii, 170, 178; expressiveness of tone of, xv, 144; fear effects on, xi, 132; modulations of, iv, 209, 232; pitch in public speaking, 232; quality of, to what due, 233; range of human, ix, 99; sound of, in dense atmosphere, 31-2; use of, in communication, xv, 151-2 Voice Organs, in birds, xii, 248-9 Voice Production, motions of, ix, 83 Volatile Liquids, iv, 174 Volcanic Activity, distribution, iii, 100 (map), 227 (map), xiv, 314-21; hot springs and, 143, 144; of past ages, iii, 177, 191, 196, 197, 203, 219, 226-9 Volcanic Belts, xiv, 314-17 Volcanic Bombs, xiv, 323 Volcanic Cones, xiv, 100-2, 225; oceanic, 277, 289 Volcanic Dust, xiv, 324; from Krakatoa, i, 18, 57-8, iii, 101, xiv, 325; from Tomboro, i, 360; from various eruptions, iii, 102-3; in atmosphere, i, 53, 57-8, 360; in ocean, iii, 54-5, xiv, 325; soils of, xiv, 69, 329; temperature effects, i, 58-9, 360; thick deposit in Colorado, iii, 229; wind carried, xiv, 327, xiii, 344 Volcanic Earthquakes, xiv, 338-9 Volcanic Eruptions, iii, 99-103, xiv, 321-9; earthquakes and, iii, 93-4, xiv, 338-9; temperature effects, i, 58-9 Volcanic Islands, xiv, 277, 289, 314, 316; new, 319 Volcanic Necks, iii, 111; of Mount Pelee, 103 Volcanic Rocks, iii, 13, 384, xiv, 99-100; distribution in western America, iii, 227 (map); extrusive, xiv, 105; land forms in, 100-5 Volcanic Soil, xiv, 69, 329 Volcanoes, iii, 99-110, xiv, 312-29; carbon dioxide from, i, 13; distribution of active, iii, 100 (fig.), 227 (map), xiv, 314-21; earthquakes and, iii, 93-4, xiv, 331, 338; energy stores and harnessing of, v, 178-80; fire source, xv, 230; in sea, xiv, 285-6; materials from, 104, 323-4 Voles, xii, 285, 290 Volga River, base level of, xiv, 164; continental character, 153 Volition, xi, 259-67 (see Will) Volkmann, on tedium, xi, 195; pupil of Muller, x, 118 Volta, Alessandro, vi, 18-19, xvi, 122 Voltaic Cells, iv, 272, 295-6 Voltaic Pile, vi, 18-19, 61-2, 72; invention, xvi, 122, 189 Voltaire, messengers, xvi, 11; naturalism of, 111, 117 Volterra, soffioni of, v, 179 Volt-coulomb, iv, 294 Voltmeters, vi, 62, vii, 153-65, 376; ammeters used as, 167-8; electromagnetic, 171; galvanometers as, 179; invention, vi, 23; Kelvin's, 24 Volt Ratings, vi, 53; importance, 9, 72 Volts, Voltage, iv, 280-1, 284, vi, 53-4, 57, vii, 376; amperage, resistance and, (see Ohm's Law); changed by converters, vi, 345-8; dangers of excessive, 9, 72; decrease in transmission, vii, 189; direct current, 164; high, in smoke precipitation, vi, 164; high, in transmission, 159-61, 331-2, vii, 10-11; induced and generated, 370; magnitude, on what dependent, 139, 144-5; measurement (see Voltmeters); regulation, vi, 188, 328-9, 346; regulation in automobiles, vii, 144-50; regulation in motors, vi, 226-8; residual, 191; stepped up and down, 309-10; terminal and generated, 186; transformation, 159-61 (see Transformers); watt-seconds in relation to, 82, 85 (see also Electromotive Force) Voltage Regulators, vi, 188, 328-9, 346 Volume, metric units of, viii, 28; of gases, laws, 106-8 Volumetric Analysis, viii, 291, 292-5 Voluntary Actions, factors, xi, 260-5 Vomiting, cause, xi, 39 Von Kluck, course of, xiv, 92 Vortices, atmospheric, i, 134-5; Descartes' theory of, ii, 60 Vosges Mountains, xiv, 87 (map), 90, 117 Vowel Sounds, nature of, xi, 104; photograph record of, iv, 234 Vries, Hugo de, on mutants, xiii, 333, 334 V-shaped Depression, i, 238, 384 Vulcan (planet), ii, 189 Vulcanizing of Rubber, xiii, 245; sulphur used in, viii, 77, 257-8 Vulcano, dormant volcano, xiv, 317 Vulcanology, science of, xvi, 38 Vultures, xii, 260 Waialeale, Mount, rainfall on, i, 112 Waiting, slowness of time in, xi, 194, 195, 196 Wakefulness, causes of, ix, 218-19 (see also Insomnia) Wake Robin, xiii, 176, 183 (fig.) Wales, Britons in, xiv, 243; geology of, 271-2; marriage by capture in, xv, 283 Walking, act and processes, ix, 89-90, 156-8; balance, how maintained, xi, 31; chain reflex in, 250; correct carriage in, x, 305, 306; as exercise, 304, 317; high heel effects on, ix, 69; of children, 351; of men and apes, xv, 58; work equivalent, x, 305 Walking Ferns, xiii, 65 Walking Machines, v, 215-16 Walking Stick, ix, 9, xii, 107-8 Wallabies, xii, 278-9, 280 Wall, Dr., on lightning, vi, 14 Wallace, A. R., on distribution of animals, xvi, 140; on Martian life, ii, 248 Wallis J., mathematician, xvi, 113-14, 115 Wallpack Ridge, xiv, 51 Walnut Tree, antiquity of species, xiii, 324-5; family, 191; petals absent, 190; sexes in, 46, 191; in U. S. forests, xiv, 373 Walpurgis Night, i, 184 Walruses, xii, 334-5; in glacial period, xiv, 376 Walschaerts Gear, v, 210 Walter, Dr. B., i, 147 Walter Reed Hospital, x, 189 Walther, patron of Regiomontanus, ii, 40, 41 Wapiti, xii, 317-18; antlers of, 316 War, "art" of, i, 306; chemistry in, viii, 262-4; crowd psychology in, xi, 330-1; destructiveness of modern, v, 359; engines of, 359-75; inventions and, 12, 350-60, 375; meteorology in, i, 306-15; science and, xvi, 9; topographical considerations in, xiv, 92-3 Warblers, colors of, xii, 245-6 War Dances, xv, 307 Warm-blooded Animals, diseases of, x, 206; temperature regulation in, x, 250, ix, 305 Warm-bloodedness, ix, 305; advantages, 306-7; importance of, xii, 244, 271 Warmth, sense of, ix, 93-4, 319-20, xi, 109, 112, 113, 114 Warping (geological), xiv, 35-6, 37, 38-9 Warp Threads, v, 278-9, 281, xv, 244-5, 246 (fig.) Warren, Dr., x, 125 Wart-hog, xii, 310 War Vessels, first steam, v, 378 Wasatch Mountains, faulting in, iii, 89, 90-2, 152; fault scarp of, xiv, 117, 122, 124, 230; parallel beach lines on, 207; recent uplift, iii, 39 Washing Machines, Electric, vii, 78-82, 90 Washing Soda, viii, 135 Washington, (city), malaria reduction in, x, 300 Washington, (State), earthquakes in, xiv, 331; forests in, 374; lava formations, 102, 104, 318 Washington Monument, diurnal gyration, v, 71 Washington Thorn, xiii, 198 (fig.) Wasps, xii, 125-6; appearance in Tertiary, 104; nests of, xv, 266 Watches, balance wheel construction, iv, 148; historical development, v, 57, 65, 379; mechanism, 68-72; precision of modern, 67-8; radium dials, iv, 380; screened from magnetism, vi, 32 Watchung Mts., xiv, 111 Water, atmospheric content, viii, 67; basic element (Thales), xvi, 77; body needs and uses of, viii, 355-6, 357, 358, ix, 37-8, 173, 233, 246-7, 262, 272, 273, 274, 276; body percentage of, viii, 348 boiling of, by cooling, iv, 168-9; boiling point, i, 73, iv, 136, 137, 141, 168, 178; boiling point and pressure, 170, v, 354, viii, 303; buoyant power of, iv, 104, 105; capillarity, viii, 37; catalyzing power, 103; chemical composition, 26, 39-40, ix, 26; chemical properties, viii, 38-40, 355-6; cleansing agent, 142; color and taste, 40; compounds of, 38-9, 70, 79-80, 89, 152-3; compressibility, v, 106, 107; cooling by evaporation of, iv, 174, v, 349-50; critical temperature and pressure, iv, 171-2, 173; decomposition, viii, 21, 39, 101-2, 134, 184; density of, iv, 113; density standard, 111, 112, 149; distribution of, on earth, xiv, 20-5; drinking of, and obesity, x, 275; drinking of, at meals, ix, 229; electrical conductivity of, iv, 296; electrolysis of, viii, 30-1; expansion on freezing, iv, 149-51, 163, viii, 38, xiv, 75; fire extinguishing by, viii, 57; fluid temperatures, ii, 244; foreign substances in, viii, 40-1; forest requirements, xiv, 377-8; formed by body tissues, ix, 262; formed as by-product of salts, viii, 115, 116-17; freezing of, warming process, iv, 161; freezing of, while boiling, 169; freezing point, i, 73, 136, 137, 141, 173; freezing point, lowered by alcohol, viii, 299-300; geological work (see Streams, Rivers, Lakes, Ocean); grass requirements, xiv, 381; ground (see Ground Water); hardness of, viii, 151-2, 318, 377, iii, 126, xiv, 147; heat capacity of, iv, 155, 162-3, 186; heat conductivity, 176, 179; heat convection in, 177-8; heat developed in formation, viii, 95-6; heating of, mechanical equivalent, iv, 49-50, v, 350; height of rise in vacuum, iv, 27; hydrogen produced from, viii, 30-2; hydrolysis, 39, 217-18; imperviousness of clay to, xiv, 137; importance, viii, 36; in animal body and plants, 348, 355-6; in carbohydrates, 223, 224; in carbon-hydrogen cycle, 350; in protoplasm, ix, 37-8, 282; in various foods, viii, 362, 363, 364, 365; infant's need of, ix, 350; interestingness of, xvi, 14; ionization of, viii, 123; "juvenile," xiv, 151-2; kinetic energy, v, 84-5; latent heat of, iv, 161, 174, 188, v, 169, 353-4, viii, 38; laws of, widely known, vi, 106; mechanical uses (see Hydraulic Machinery); machines for raising, iv, 26-7; men's need of, xiii, 101-2; metabolism affected by, ix, 37-8; metric measurements of, iv, 111, 112; a mineral, iii, 308; mixtures at different temperatures, iv, 153-4; mixtures with ice, 160-1, v, 353-4; necessity of, to life, x, 275, ix, 37-8, xi, 66, xiii, 101-2; of chemical union, viii, 38-9; of crystallization, 38; of limestone regions, xiv, 147; ore deposition by, viii, 199; origin of life in, ii, 243, 244, xvi, 78; origin on earth, iii, 160, 163; oxygen in solution, viii, 35, ix, 182; photographing objects under, i, 47-8; physical properties, viii, 37-8, 40-1, 355; plant fertilization by, xiii, 123, 149-52, 158-9, 160, 161, 165; plants' storage of, 28, 41-2, 106-7, 378, 379, 380; plants' use of, viii, 335, 337-8, 347, xiii, 90-6, 101-9, xiv, 65, 377-8, 381, ix, 26-7; power in atoms, vi, 115; pressure of, iv, 117-19, v, 94-5, vi, 47-9, 56; produced by combustion or decay, viii, 61; produced by volcanoes, iii, 107; purified by ozone, vii, 354-5; purification by dissolved oxygen, viii, 40, 111; purity of flowing, iii, 121; rate of flow, vi, 68-9, 70-1; reflection of light by, iv, 373-4; reflection of objects in, 337; refraction of light by, 323, 326-7, 331, 373-4; resistance, v, 190-2; rock-weathering by, iii, 22-3, 24-6, viii, 194-5; seed dispersal by, xiii, 346-8; softening of, viii, 135, 152, 323-4; soil, xiii, 92; solvent action and solutions in, viii, 37, 111-13, 120-1, 217; sound transmission by, v, 107, 108; sound velocity in, iv, 201; specific gravity basis, 109, 111; specific heat of, 155, viii, 37; states of, iv, 22, 131, 139, 151-2; supercooled, viii, 113; temperature in steam engines, v, 139-40; temperature of greatest density, iv, 149, v, 350; terrestrial, circulation and sources, xiv, 134-5, 151; therapeutic uses of, x, 85, 383; transparency in Lake Tahoe, iii, 154; weight of, iv, 117, 149, v, 94, vi, 80-1, 147; within the earth, iii, 109-10, 113-29 Water-bearing Strata, excavating through, v, 116-17 Water Birds, xii, 250-9; feathers of, 244; sleeping of, xi, 287 Water Boa, xii, 216 Water Boatmen (insects), xii, 114 Water Bugs, xii, 114 Water Chestnut, source, xiii, 266 Water Clocks, ancient, v, 59-63 Water-cooled Engines, v, 159-61 Water Cress, taste, xiii, 197 Water Dogs, xii, 171 Water-dripping Plants, xiii, 107-8 Water Drops, atmospheric, i, 91-2, 93, 95; phenomena due to, 150, 166, 175, 177, 183 "Wateree," U. S. S., xiv, 337 Waterfalls, caused by Ice Age, iii, 242-3; energy of, iv, 81; in glacial valleys, xiv, 57; in homogeneous rock, 132-3; in old and new regions, iii, 33-4, xiv, 48, 49, 57, 159; types, iii, 44-50 Water Gaps, xiv, 98 Water Glass, viii, 141 Water Hammer, in pipes, v, 84, vi, 254, 364 Water Hemlock, seeds, xiii, 201 Water Jets, digging with, v, 88; dredging with, 258; power, 80; propulsion of boats by, 190; vena contracta of, 89-90 Water Lilies, Amazon, xiii, 359-60; class of, 196 Waterloo, Napoleon's indigestion before, ix, 238; weather conditions, i, 307 Watermelon, xiii, 54, 227; water content, viii, 365 Water Meters, v, 87-8 Water Organ, v, 110-11 Water Pipes, bamboo stems as, xiii, 183; bursting of, iv, 151, xiv, 75; electrical thawing, vii, 336-9; electrolysis, 188; rate of flow in, vi, 71; water hammer in, 254, 364, v, 84 Watering Places, xiv, 145 Water Plethysmograph, xi, 284 Water Power, coal and, xiv, 31, 191; compressing air with, v, 89-93; discovery of, xv, 240-1; early and present use, v, 75-6, 173, xiv, 31; electricity from, vi, 162-3, 351-2, 361-70; future possibilities, v, 83-4; gravity the real power, 76-7, 139; growing use of, viii, 267, 283; high head importance, v, 77; in mountain countries, xiv, 242; use on farms, vii, 233-4; "White Coal," v, 174 (see also Hydraulic Machinery, Hydroelectric Plants, Water Jets, Water Wheels) Waterproofing, by rubber, xiii, 245 Water Ram, v, 84-6 Water Scorpions, xii, 114 Watersheds, Atlantic-Pacific, xiv, 189-90; in young and old regions, 158, 161 Water Snakes, xii, 217-18 Water Solubles (vitamines), x, 260, 261, 262 Waterspouts, i, 138, 384; cores, 299; lifting power, 356; superstitions, 335 Water Supply, common sources, viii, 317-18; from wells, iii, 118, viii, 317-18, xiv, 139-40; of American cities, viii, 317, 318, 320, 322, xiv, 140-1; pollution and purification, viii, 41, 317-24, xiv, 139-41; purification by chlorine, viii, 86, 321; purified by compressed air, iv, 130-1; snow sources, i, 118; typhoid contamination of, x, 287 Water Table, iii, 113, 118, xiv, 136; rise of, i, 355 Water-tube Boilers, v, 140 Water Turbines, v, 82-3, vi, 361-2, 363-4; efficiency, v, 170; at Keokuk Plant, 81-2, 82-3; of Niagara Power Plant, vi, 372-3, 374-5 Water Vapor, atmospheric, i, 10, 11, 14-15, 76, iv, 183; precipitation, i, 90-6, 113, 115, 120, 121; need of nuclei for condensation, viii, 113; saturated pressure of, iv, 168, 169 Water Wheels, early use, v, 19, 75, 76; energy used by, iv, 181; former and modern types, v, 76-7; invention of, xv, 240-1 (see also Pelton Wheels, Water Turbines) "Waterwitch," steamboat, v, 190 Water Witches, iii, 123, 124 Water Yam, xiii, 89-90 Watkins Glen, iii, 44, 243 Watson, Sir Thomas, x, 112 Watson, Prof., asteroids of, ii, 256-7 Watt, James, power unit named for, iv, 285; steam engine, v, 44, 47, 144-6, 376, 377, xvi, 125 Watt, Sir George, book on Indian plants, xiii, 266 Watt, power unit, iv, 80, 285, 310, 312, vi, 84-5, vii, 376; method of ascertaining, vii, 166; value in candlepower, iv, 352 Watt-hour, iv, 312, vi, 82; erg and calorie equivalents, vii, 382 Watt-hour Meters, vii, 174-7 Wattmeters, vii, 172-4, 376; electromagnetic, 171 Watt-second, vi, 82, 84, 85 (see also Joule) Wave Length, iv, 196, 213, 214 (fig.), 384 Wave Meters, vii, 292-5 Waves, Ocean (see Ocean Waves) Waves (vibrations), defined, iv, 196, 384 (see also Light Waves, Sound Waves, etc.) Wax Candles, viii, 246, 247 Waxes, viii, 245-6, 350 Weak-Mindedness, facial expressions of, xv, 63, 64 (fig.) "Weaning" Treatments, xi, 248 Weapon Salve, x, 79 Weapons, evolution of, v, 12-13, xv, 102-10, 190-2, 205-21 Weariness, indigestion from, ix, 241 Weasel Family, xii, 347-51 Weasels, xii, 348-9; storing of food by, 292 Weather, aeronautics and, i, 284, 285; atmospheric pressure and, 237-8, 241-2; business dependence on, 261-70; climate and, 199; clothing in relation to, x, 309-10; "comes from west," xiv, 350; control of animal and plant life, i, 254; correlation studies, 253; crops and, 245-50, 252-3; cycles, 242; elements and how observed, 70-89; heights of phenomena, 17, 18; human effects, 316, 323-4, 330-1; military importance, 306-15; modern commenting on, 66; moon's influence, ii, 201; predictions for future eclipses, 217; pressure areas and, i, 135, 218, 237-8, xiv, 349-50; "recurrence," i, 363; solar radiation and, 218-19, ii, 186-7, iv, 194; sun-spots and, i, 16, 242, ii, 186; variety in relation to efficiency, xiv, 357; world-wide interrelations, i, 218, 241-2 Weather Bureau (see U. S. Weather Bureau) Weather Forecasts and Forecasting, i, 224-6, 236-44; advertising and, 265-6; aeronautical, 18, 304-5; agricultural, 256-7; basis, 135; frost, i, 260; history of, xvi, 102, 177; kites and balloons in, i, 22; "odds," 314; rainbows in, 177; small progress in art, 382; sunrise and sunsets in, 166; United States, 216-17 (see also Weather Predictions) Weather Glass, i, 70 Weather Instruments, i, 68-89 Weather Insurance, i, 269-70 Weather-Making, i, 332-45 Weather Maps, i, 225-36; "flat," 239, 372; marine, 273-6; shipboard, 281; winds on, 125-6, 134 Weather Observations and Reports, i, 66-89, 213-23; aeronautical, 304-5, 314; earliest instrumental, 201; humidity in, xiv, 353-4; marine, i, 274-6, 280-2; used in crop forecasting, 251-2; World War, 310, 314 Weather Predictions, long range, i, 241-4; value to farmers, 249-50 Weather Prophets, distribution, i, 243 Weather Proverbs, i, 106, 177 Weather Vanes, ancient, i, 68; common and scientific, 82 Weather Wells, i, 354, 384 Weathering of Rocks, iii, 22, 384, viii, 194-5, 338; agencies and processes, iii, 22-9, xiv, 41-3, 62-4, 75-9, 105-6; determined by character and arrangement of rocks, 44, 79, 130, 133; in deserts and arid regions, iii, 23, 72, xiv, 41-2, 62, 69, 77-9; on mountains, iii, 23-4, xiv, 40, 233; plutonic rocks, 105-6, 107, 110, 112-13 Weaving, historical development of, xv, 243, 244-7; pattern-making, v, 280-2; threads, 276, 278-80 Weber's Law, xi, 184-5 Webs, of spiders, xii, 94, 95-6 Webster, Daniel, brain weight, xv, 39 Wedding Presents, xv, 285 Weddings, attendants at, origin of, xv, 282 Wedge, v, 37; discovery of use, 15; form of inclined plane, iv, 90; friction in, 93 Wedge (meteorology), i, 238, 384 Weeds, origin in U. S., xiii, 353-4 Weedy Plantain, xiii, 88 "Weeping Trees," i, 351 Weeping Willow, xiii, 271-2 Weft Threads, v, 278, 280 Wegener, Dr. A., i, 192 Weight, iv, 58, 74, 99, 101; defined, vi, 81, xvi, 130; diminished by earth's rotation, iv, 74-5; errors in perception of, xi, 184-5; latitude and, ii, 69, iv, 101, 102, xvi, 130; loss of, in fluids, iv, 104, 105, 106, (fig.), 107; mass and, 84-5, 110, xvi, 130; measured by spring balance, iv, 102; measurement of, by displacement, 103-4, 105; of gases, gram-molecular method, viii, 109; units of, iv, 46, 283-4, viii, 28 Weight (bodily), at different ages, ix, 31, 32 (diagram); metabolism in relation to, x, 271, ix; reduction of, 302; rate of reduction by fasting, x, 275 Weight Arm, in machines, v, 22, 26, 31, 32, 33 Weights and Measures, British and metric units, iv, 45-6, 69-70; practical units, 283-4; scientific standards, xvi, 129-30 (see also Units) Weismann, germ plasm theory, x, 230; on adaptations, xvi, 152 Welding of Metals, i, 33; electric, iv, 312; Goldschmidt method, viii, 155 Wells, airlifts in, iv, 130; artesian, iii, 118-19, xiv, 12, 138; blowing, i, 353-5, 368; drilling of deep, iii, 119-21; drying of, xiv, 136; gases and minerals in water, 141-2; Green's drive, v, 380; locating of, iii, 123-6; pumping systems for deep, v, 114-15; sanitary aspects, iii, 121-3, xiv, 139-40; source of, 138-9; sunk in granite, 137; water supply from, iii, 118-19, viii, 317-18 Wells, E. I., on railroads, i, 267 Wells, Horace, x, 124, 125, xvi, 185 Wells, Spencer, xvi, 184 Welsbach Gas Mantles, vi, 264, viii, 252; invisible rays, xvi, 192 Welsh Language, xv, 162 Welsh People, in Mediterranean Group, xvi, 49; mountain isolation of, xv, 130 Welts, hypnotic production, xi, 317 Welwitschia Mirabilis, xiii, 380-1 Wentletraps, xii, 71 West Africa, beetles of, xii, 124; crocodiles of, 199-200; coast of, xv, 136; forests of, xiv, 366, 368-9; hanging valleys in, 58; harmattan of, i, 134; monkeys of, xii, 379; monsoons, i, 131; python of, xii, 214; river shrew of, 367; sleeping sickness, x, 169; tornadoes of, i, 137 Western American Volcanic Belt, xiv, 315 Western Forest (U. S.), xiv, 373-4 Western Pacific Volcanic Belt, xiv, 315-16 Western Union Telegraph Co., vii, 107-8, 112; early weather forecasts, i, 216 West Indies, boa constrictor of, xii, 215; clove production, xiii, 262; coffee in, 233; concordant coasts of, xiv, 249; coral reefs in, 305; earthquakes in, 331; hurricanes, i, 136, 375; hurricane reports, 280-2, 309; mongooses in, xii, 352; nutmeg production, xiii, 262; poisonous snakes, xii, 234; sea-shells of, 73; sharks of, 143; sponges of, 32; spurge, xiii, 30-1; vanilla production, 259; volcanoes of, xiv, 316 Westerly Winds, region of prevailing, i, 128, 129 Westinghouse, George, air-brake, v, 130, 380 Westinghouse Electric Co., machinery for Niagara Plant, vi, 374, 375, 376 Westminster Abbey, weathering effects, iii, 22 West Virginia, natural gas, iii, 355 Wet Bulb Thermometer, i, 78-9, 318, 384 Wetness, exposure to, effects of, x, 239; sensation of, xi, 128 Wet Steam, v, 140 Whalebone, xii, 298 Whales, xii, 297-9; sawfish and, 149; squids and, 80 Whale's Food, xii, 19 Whaling Industry, aerial patrol in, i, 48 Wheat, ancestral home, xiii, 182, 221; economic importance, i, 263, xiii, 208; food value, viii, 364, x, 259, 261, 262, 267, 278, 279; fruit for seed dispersal, xiii, 56; germination of seeds, ix, 16-17, xiii, 211; history and forms, 210-11; in grass family, 179; Mediterranean source, xiv, 382; phosphate requirements, 67; protein in, xiii, 95; rust, 13; snow and, i, 253; stalk stiffening, viii, 337; starch made from, 243; time required to produce, v, 249; vitamines in hulls, ix, 35, 36 (see also Winter Wheat) Wheatstone Bridge, iv, 301, vi, 80 Wheel and Axle, v, 31-3; action of, like lever, iv, 89 Wheel Lock, xv, 217 Wheeled Vehicles, use on farms, v, 215 Wheels, centrifugal force of, iv, 71; discovery and development of, xv, 241-3; evolution of, v, 16-17, 205; form of lever, 21, 28; friction, 204; friction-saving by, 205-6; large and small, 206; not found in nature, 16, 215; tendency to turn on center of gravity, 150; in transportation, 214-15 Whelks, xii, 72 Whippoorwills, family of, xii, 267; feathers about mouth, 244 Whirlwinds, dust, i, 60 Whiskey, making of, viii, 250 Whispering Galleries, iv, 239 Whistles, policeman's, iv, 220; siren, 205 Whistling, impossible in caissons, iv, 32 White (color), reflection of light by, x, 309 White, Andrew D., on comets, ii, 84 White, Charles, x, 92 White, D., quoted, iii, 202, 343 White, I. C., anticlinal theory, iii, 352 White, Maunsel, v, 55, 383 White, Orlando E., xiii, 221 White Ants, xii, 110 White-blood, metabolism in, x, 272 "White Coal," v, 76, 174 White Corpuscles, ix, 182 (fig.), 184-8; germ destruction by, 185-7, x, 197, 209-10; passage through capillary walls, ix, 194 Whiteface, Mount, spring on, iii, 117 Whitefish, xii, 154, 159 White Flies, xii, 112 White Flour, vitamines absent in, x, 267, ix, 35 Whitehead Torpedo, v, 380 White Heat, temperature of, iv, 361 White Lead, viii, 162, 265 White Light, iv, 364; composition, Colors, i, 165, iv, 357-9, 366-7, vi, 282, viii, 301, ix, 115, 3579, xvi, 119; hands and face in, iv, 364-5 White Mts., Arctic species in, xiv, 377; club mosses of, xiii, 305; in Mesozoic Era, iii, 232 White Pine, in northern forests, xiv, 372; region of, xiii, 368 White Plague, x, 290, 294 White Race, xv, 32; beards in, 38; brain weight, 41; characteristics indefinite, 35-6; disease immunity and susceptibility, 48, 49-50; eyes, color of, 37; facial angle in, 45; hair, color and form of, 37, 38; in tropics, i, 327, xiv, 344, 356-7, xv, 49-50; jaw angle of, 44; language relationships, 161-3; light and dark divisions, 37; measles in, 48; nose index and nostril shapes, 45, 46; savages' ideas of, 334; separate origin theory, 70; skull index in, 42; skull capacity, 41 White Rainbows, i, 176, 384 White Rats, protein experiments on, ix, 287-8, 288 White Swelling, x, 78 "White Way" Lighting, vi, 279, vii, 339-40 White Whales, xii, 297 Whitman, Walt, "Song of Myself," xi, 336 Whitney, Eli, v, 269; cotton gin, 269-71, 376, xiii, 237-8; milling machine, v, 47, 378; standard muskets, 49-50 Whitney, Mount, observatories on, ii, 144, 149 Whitney, Professor, on emphasis, xv, 144; on language changes, 157 Whittlesey, Lake, iii, 148 Whole Wheat Bread, vitamines in, x, 267 Whooping Cough, consumption from, x, 292; germ of, 216 Wickam, H. A., "botanical specimens" of, xiii, 247 Widal Reaction, x, 216 Wilberforce Spring, iv, 83-5 Wilcox & Gibbs Machine, v, 285 Wild Arum, fertilization, xiii, 153 Wild Asses, xii, 308 Wild Boar, xii, 310; in Cro-Magnon paintings, xv, 114 Wildcats, xii, 356 Wild Dogs, xii, 345 Wild Ducks, seed dispersal by, xiii, 340-1 Wilderness of Judæa, xiv, 121 Wild Horse, xii, 306-7 Wild Mustard, origin in U.S., xiii, 353-4 Wild Ox, xii, 330-1 Willets, xii, 262 Will or Volition, xi, 259-67; hypnosis and, 317, 318; motor character, 61; source of energy of, 33 William the Conqueror, at Salerno, x, 36, 37 Willamette River, navigability of, xiv, 195 Williams, Prof. Samuel, ii, 211; quoted, i, 201 Williams, Wells, on Chinese astronomy, ii, 21 Williamson, chemical work, xvi, 133-4, 162, 165 Willis, Thomas, xvi, 108 Will-o'-the-Wisp, i, 346-9 Willow Trees, antiquity of species, xiii, 324-5; family, 191; fertilization, 122; origin and product, 244; petals absent, 190; seed dispersal, 343; sexes in, 47, 191; sprouting of, 166 Willughby, xvi, 126 Wilson, A. B., sewing machine, v, 284-5, 379 Wilson, T. L., xvi, 190-1 Wimhurst Influence Machine, vi, 301 Winch, iv, 90-1 Winchell, A. N., i, 55 Winchester, James, quoted, i, 360 Wincing, origin, xi, 133 Wind, Winds, cause and general system, i, 124-9, xiv, 347-51; climate determined by, 345-7; complex structure, i, 292-8; defined, x, 384; direction, how observed, 82; drying power, 77; due to sun, v, 177, xiv, 32; dust-carrying by, i, 52-5, iii, 71, 73-5, xiv, 77, 327; eddies and updrafts, i, 53; force measurement, 83-4, 294-6; force in relation to isobars and altitudes, i, 126; geological work, iii, 71-5; gusts, i, 295; human control, i, 332, 333; in aeronautics, 284-6, 289-300; lifting effort on kites, iv, 76 (fig.); lightning and, i, 148; local names, 132; ocean, 271-6; ocean currents caused by, xiv, 303; plant fertilization by, xiii, 118, 123, 148-9; power to blow objects aloft, i, 356; pressure areas and, i, 124-6, 127-9, 134-5, 218, xiv, 349-50; pressure due to inertia, v, 234; projectiles and, i, 312-13; rainfall and, 111; rock destruction by, iii, 72-3, xiv, 41, 45, 62, 77, 233; sailing against, iv, 77 (fig.), v, 182, 186-8; seed dispersal by, xiii, 58-9, 156, 340, 343-6; soils deposited by, iii, 73-4, xiv, 71-5; sound and, i, 187, iv, 210-11; superstitions, i, 334-5; topography and, 292, 294 (fig.), 296-7; types, 130-9; use of power, 37-8, v, 75, 111, 173, 182; velocity and force, i, 83, 84, 137, 138; vertical, 293; waves caused by, xiv, 299; weather and, i, 237-8, xiv, 349-50; worship of, by Polynesians, xv, 342 Wind Aloft, i, 384 Wind Aloft Maps, i, 230, 231, 233 Wind Charts, i, 206, 271-3 Wind Gaps, iii, 39, 38 (fig.), xiv, 58, 98, 169 Wind Instruments, iv, 231; development of, xv, 316-17 Windmills, v, 75, 111; modern use, i, 37-8 Windpipe, cartilage in, ix, 57; connections and parts, 255 Wind Rose, i, 273-4, 384 Wine, alcohol in, how measured, iv, 113; flavors of, viii, 248-9; pasteurization of, x, 139-40; religious uses, primitive, xv, 352 Wine Making, viii, 248-9; Pasteur's discoveries, x, 138, 139-40 Wine Palm, xiii, 53 Winged Fruit and Seed, xiii, 58, 345-6 Wings, of birds, xii, 247 Wings, of flowers, xiii, 47-8 Wing Shells, xii, 73-4 Winkles (shellfish), xii, 72 Winnepeg, Lake, iii, 144 Winter, effects on life, xi, 51; human efficiency in, i, 323; keeping warm in, ix, 309, 312; land and sea winds in, xiv, 346; mild and severe, how determined, 350; "old fashioned," i, 200-2; thunderstorms, danger of, 156 Winter-Days, temperature, i, 205, 384 Wintergreen, origin, xiii, 255 Wintergreen Plants, xiii, 202 Winter Provender, of rodents, xii, 292-3 Winter Wheat, best time to plant, i, 256; snow and, 253 Wireless Communication, vii, 258-98; condensers in, vi, 303, 304; dependent on simultaneous reactance, 171; hot-wire ammeters in, vii, 163, 164 (see also Radio) Wireless Control, of aeroplanes and ships, vii, 283-4 Wireless Signals, in aeronautics, i, 291, 292, 302 Wireless Telegraphy, iv, 313-16; alternating currents in, vi, 168; conditions of transmission, vii, 272-3; detectors, 268, xvi, 191-2; history, 191; induction coils in, iv, 305, 313, 314; resonance in, 226; strays or static, i, 162-3; theory for amateurs, vii, 285-98; vacuum tubes in, vi, 125, vii, 276-80; weather reporting by, i, 257, 269, 280-2, 315; in World War, vii, 283 (see also Wireless Communication) Wireless Telephony, iv, 315-16; aeronautical uses, i, 44-5, 302; alternating currents in, vi, 163; current conversion, 339-41; development of, vii, 280-3; distress signals, 284; theory for amateurs, 285-98; vacuum tubes in, vi, 125, 339-41, vii, 276, 278, 279, 280; weather reporting by, i, 257; in World War, vii, 282-3 (see also Wireless Communication) Wires, current-capacity table, vii, 58; leakage, 10-11; measure (circular mils), iv, 282-3; measure (mils), vi, 77, vii, 373; resistance of, iv, 281, 282-3, vi, 79; sizes and kinds in transmission, vii, 20-4; standard tables, (copper), 378-81; types of insulation, 58 Wireworms, xii, 124 Wiring, interior, vii, 51-72; exterior (see Overhead, Underground Transmission) Wishbone, of birds, xii, 247 Wisby, in Hanseatic League, xiv, 282 Wisconsin, drainage studies in, xiv, 131; drumlins of, iii, 69, xiv, 60; Ice Age in, iii, 239; lakes of, xiv, 200; terminal moraines in, 59 Wise, John, rip panel inventor, v, 224 Wiseman, Richard, x, 78 Wishes, dreams from, xi, 293, 299-300, 301-2; suppression of, 140-2, 257 Wistar, Casper, x, 116 Wit, psychology of, xi, 350-7 Witchcraft, former theories of, x, 357, 360 Witches, colonial ordeals for, xv, 373 Witchhazel, origin, xiii, 255 Witch-Hazel Plant, seed dispersal, xiii, 339 Witnesses, influence of forms of questions, xi, 308-10; untrustworthiness, 103, 168 Woevre, France, xiv, 91 Wöhler, Friedrich, x, 126 Wolf, astronomer, ii, 134 Wolff, Caspar F., xvi, 118 Wolf-Rayet Stars, ii, 116 Wollaston, William Hyde, xvi, 122, 162; spectrum studies, ii, 111, 112 Wolverine, xii, 348-9 Wolves, xii, 340-2; dogs and, 344; ears of, 346; in Great Britain, xiv, 273; Tasmanian, xii, 277 Wombat, xii, 278 Women, basal metabolism of, x, 271; bearing of pain by, ix, 87; brain weight in, xv, 39; color-blindness in, ix, 116, 340-1; dress of, x, 309; ear-rings of, xv, 259; food requirements, viii, 367; heart rate in, x, 334; height of, xv, 38; modesty and immodesty in dress, 254-5; painting of, 256; skull capacity, 40; susceptibility to temperature changes, x, 240; voice tones of, ix, 99 Wonder, in various sentiments, xi, 146, 147 Wood, chemical material of, viii, 44; decay of, xiii, 71; distillation for wood alcohol, viii, 214; electrical conductivity, iv, 259; flame of burning, viii, 57; heat conductivity, iv, 176, 177; percentage of carbon in, viii, 44; petrified, iii, 15-16; sound velocity in, iv, 201; storage appliance of plants, xiii, 96; use as food, ix, 24 (see also Heartwood, Sap wood) Wood, Henry Wise, v, 383 Wood Alcohol, viii, 214; flame of, 60; used as denaturant, 250 Wood Ashes, lye from, viii, 276; potash in, 279, 343, 344, xiv, 67 Woodchucks, xii, 295 Woodcocks, xii, 263 Wood Lice, xii, 82 Woodpeckers, xii, 267; mating of, xv, 276-7; toes of, xii, 265; use of tools, v, 11 Wood Pulp, in paper making, v, 290, 292-5, 380 Wood Sorrels, leaves, xiii, 88-9, 113 Woodward, Dr. Robert S., ii, 147, xvi, 126 Woody Tissue, composition, xiv, 65 Woof, of woven goods, v, 278, xv, 244 Wool, as clothing material, x, 307, 308, 309, ix, 311; chemical properties and manufacture, viii, 256; dyes of, 259; electrification of, iv, 257, 258, 259; humidity effects in manufacture, i, 78; removal of cotton from, viii, 255; warmth, to what due, iv, 178 Wool Grass, xiii, 182 (fig.) Wool-pack Clouds, i, 101-2, 384 Woolwich Observatory, founding, xvi, 127 Woolworth Building, elevator system, v, 134-5; height of tower, 79; flood lighting, vi, 283 Wordsworth, paradox of, xi, 247 Words, changes in meanings of, xv, 157; double meanings, 158-9; inadequacy in feelings, 143; origin of various, 153-4, 157, 161 Work (labor), conditions of, importance, xi, 361-2; daily amount in calories, ix, 297; daily amount in foot-tons, x, 305; effect of distractions, xi, 277; fatigue and capacity for, x, 246, 247; fatigue from new, ix, 81; fatigue in pleasant and unpleasant, xi, 274-6, 277-8; food energy consumed by, viii, 367; planning of, xi, 377-8; rest periods and efficiency, 363 (see also Vocations) Work (mechanics), iv, 37, 38; accomplished by inequalities, viii, 168; energy and, iv, 37-40, 78-88; heat relations to, 189-91, 193; measurement and units, 78, 79-80, 189-90, vi, 81-2, 84; rate of, iv, 80 (see Power) Workers, food requirements and energy of, viii, 367; instruction of beginners, xi, 363-5; interest of, 376; jobs and, 358-61; tool adjustment to, 362 World War, aeronautical development, i, 40-1, 284, 285, iv, 10, 107; aeronautical weather services, i, 304-5; aeroplane accidents, x, 246; aeroplane machine guns, v, 107; aeroplane mapping, i, 45; aeroplanes, luminous glories seen, 185; aftermath of, x, 188-9; artillery phenomena, i, 193-4; artillery vs. armor, v, 368; big guns, v, 368-71; bombardment of Antwerp, i, 191; cannonading heard at distances, 188; care of disabled, (U. S.), x, 188-91; chemical warfare, viii, 262-4, x, 186-8; chemical warfare service device, viii, 283; chemistry in, xvi, 159; commerce destruction in, xiv, 306; cultural setback by, xv, 30; dried foods in, viii, 371; dye industry in, 253; electricity in, vi, 10; flood lighting, 283; flying machines, v, 233; French forests in, xiv, 239; gas masks, viii, 48; German aircraft at beginning, x, 40; German lack of jute bags, xiii, 241; German plans on two fronts, xiv, 91-2; German torpedoes, v, 374; Germans called Huns, xi, 22; Germany's nitrate needs, xiv, 66; helmets and armor in, xv, 221; hysterical phenomena in, x, 363; ignorance of southern mountaineers in, xv, 131; influenza pandemic, x, 294-5; Italy in, xiv, 244-5, 252-3, Italy in, xv, 138; invasion of France and Belgium, topographical considerations, xiv, 88-93; inventions, v, 360, 384; jaundice in trenches, x, 201; Liberty engines, v, 53-4; machine guns, 363-8; Marne retreat incidents, xi, 286-7; medical achievements of, x, 176-91, 384; meteorology in, i, 290-1, 307-15; mirages in Mesopotamia, 173; motors used, direct current, vi, 239; nitrogen needs and production, i, 34, 36, viii, 246, xiv, 66; pilot balloons, i, 22; potash dearth and supplies, viii, 143-4, 279, 344, xiv, 67; projectiles and shells, v, 372; rain in battles, i, 338; Russian bison destroyed in, xii, 329; Russian elk destruction in, 318; scientific progress in, iv, 10-11, xvi, 9, 195; scurvy in, x, 265; searchlights on fleets, iv, 352; sleeping sickness epidemic, x, 301; smoke screens, viii, 87; sound-ranging, i, 313, iv, 201-2; sphagnum use in, xiii, 160-1; stereograms in, xi, 180-1; submarines, v, 198, 200-1; submarine spotting, i, 47; sulphuric acid importance, viii, 78-9, 80; surgery in, x, 181-3, 381-2; Switzerland in, xiv, 243-4; tanks, v, 218; tetanus infection in, x, 299; trench fever in, 202; tuberculosis in France, 175; typhoid fever in, 217, 288; vitamine foods lacking in certain countries, 260; volcanic power in Italy, v, 179-80; well-poisoning in, xv, 228; wheat in rationing, viii, 364; wireless operations, vii, 282-3; "Who won it?," v, 300; wood as food in, ix, 24; Zeppelins and captive balloons, v, 227 World Weather Bureau, i, 221 Worm Gears, v, 37 (fig.), 88 Worms, xii, 44-5, 50-6; classification, iii, 259; earliest tracks, 263, 270; power of distinguishing light, ix, 105; regeneration in, xii, 170; sea, 18, 23 Worms (disease), x, 200 Worry, feeling of, ix, 153-4, 167; hardened arteries from, x, 335; indigestion from, ix, 165, 167, 240-1 Wound-Rotor Induction Motor, vi, 245, 248, 256 Wounds, antiseptic treatment of, x, 145-6, xvi, 182-3; Carrel-Dakin treatment of infected, x, 181-3, 382; former treatment, 40, 43, 54-5, 59, 78-9; healing of modern surgical, 123; painlessness to soldiers, xi, 119, 120; Paré's treatment of, 55, xvi, 108; radiation treatment of septic, x, 384 Wound Suckers, x, 91, 105 Wove Paper, v, 296 Woven Fabrics, threads of, v, 276, 278 Wright, Sir Almroth, x, 218 Wright, Orville and Wilbur, v, 231-2, 237-8, 383-4; early flights, i, 300 Wright, Thomas, ii, 350, 367, 380 Wright Machines, v, 232, 236, 237-8 Wrigley Triplets Sign, N. Y., vii, 340-1 Wrist, bones of, ix, 67, 68 (fig.); pulse in, 211 Writing, development of, xv, 164-79, 325, xvi, 60; by telegraph, vi, 98; remarks on art of, ii, 10; reflex actions in, ix, 157 Written Language, association principle in, ix, 152; importance to man, 153 Wrong, original meaning, xi, 190 Wrought Iron, v, 317, viii, 158-9 Wyberd, on corona, ii, 221 Wye Connections, vi, 209, 318, 325 Wyoming, badlands of, xiv, 82; cattle ranges, 222-3; dike systems, 106-7; marine fossils in, iii, 82; volcanic fields, xiv, 318 Xanthine, viii, 230 Xenon, in atmosphere, i, 11, 12; symbol and atomic weight, viii, 383 Xenophanes, on fossils, iii, 14 Xiphosura, xii, 81 X-ray Analysis, of crystals, viii, 313 X-ray Photography, iv, 55, 320-1; uses of, vii, 253-4, x, 222, 372-4 X-rays, iv, 317-21, vii, 249-57, x, 184-6, 254, 383; discovery of, iv, 55, 317, x, 183-4, xvi, 192-3; fluorescence produced by, iv, 320, 378-9; invisibility, 319, 378; transmitted through æther, vi, 119, 269; vibration frequency, iv, 379, vii, 260 X-ray Spectra, viii, 183, 309 X-ray Tube, iv, 319, vii, 251-2; operated by induction coils, 244; static generators for, 245 Xylene, from coal tar, viii, 253 Xylols, viii, 235 Xylophone, iv, 224 Yaks, xii, 330 Yakutat Bay, Alaska, xiv, 334-5; faulting in, 114, 334-5 Yakutsk, Siberia, i, 210 Yale College, founding, xvi, 127 Yampa River, xiv, 166, 168, 175 Yams, origin and antiquity, xiii, 224; water, of Madagascar, 89-90 Yapocks, xii, 276 Yard, unit of length, iv, 45, 69; value in meters, 46, 70 Yarn, grading of, v, 272; making and weaving of, 268, 272-82 Yawning, as fear effect, xi, 132 Yaws, racial susceptibility to, xv, 50, 51 Y-connections (see Wye) Year, beginning of, in ancient Egypt, ii, 26; in Cæsar's calendar, xvi, 98; length fixed by Hipparchus, 11, 32; length in ancient Egypt, xvi, 70; measurement of, iv, 15; without a Summer, i, 359-61, 361-2 "Yearning of Bowels," xi, 64, 131, 160 Yeast, cells of, xvi, 142-3; disease-producing, x, 196; fermentation in dough, ix, 248; fermentation by pure and other cultures, x, 138; leavening powers of, viii, 50; non-flowering plant, xiii, 13, 14, 43; origin of power, 71; reproduction, 164; vitamines in, ix, 36, x, 260, 261 Yellow, complementary color of, iv, 367; photographic action of,366; soothing effects, vi, 274; wave length of, iv, 359, 365 Yellow Days, cause, i, 57 Yellow Fever, x, 159-63; campaign against, 162, 172-3, xiv, 356-7; discovery of cause, x, 160-3, 173, 200; immunity to, 207, xiv, 357; virus of, x, 161, 200 Yellow Race, xv, 32; brain and skull capacity in, 41; diseases of, 51; facial angle in, 45; jaw angle of, 44; nose index and nostril shape, 46; peoples of, 37; separate origin theory, 70; skull index, 42 Yellowstone Lake, xiv, 180; altitude, 205 Yellowstone National Park, freaks of nature in, vii, 202; geysers in, iii, 129; Hayden Relief model, xiv, 10; hot springs, 143; jointed rocks, 129; petrified forests, iii, 126-7; travertine terraces, xiv, 146; uncooled lava masses, 313-14 Yellowstone River, canyon of (see Grand Canyon of the Yellowstone); falls of, iii, 48-9; geological history, xiv, 180 Yerkes Telescope, ii, 98, 202; magnification by, iv, 346 Yersin, bubonic plague work, x, 164, 165; pupil of Pasteur, 143 Yew Tree, ancestors of, xiii, 317; a conifer, 174; in landscaping, 270; of Tasmania, 30 Yorkshire Coast, recession of, xiv, 47, 301 Yosemite Falls, iii, 47-8, 65 Yosemite Valley, air currents, i, 296, 297; formation, iii, 44, 64-6, 225; granite walls, 112, 214; impressiveness, vii, 202 Young, Prof., astronomical work, ii, 120, 128, 142, 181, 183, 201, 222-3, 307 Young, Thomas, x, 96-7, xvi, 174 Young's Modulus, iv, 157, 158 Yperman, Jean, x, 41 Ypres, chemical warfare at, x, 186 Yssel River, xiv, 45 Ytterbium, symbol and atomic weight, viii, 383 Yttrium, symbol and atomic weight, viii, 383 Yucatan, chocolate cultivation, xiii, 234; sisal production, 240-1 Yucca Plant, pollination of, xvi, 152-3 Yukon River, use of, xiv, 191 Zambezi, crocodiles of, xii, 200 Zambezi River, gorge and falls of, xiv, 131-2, (see also Victoria Falls); lava field of, 317; varied course, 155 Zanzibar, clove production, xiii, 262, 263 Zebras, xii, 307-8 Zeno, Greek philosopher, xvi, 84-5 Zeolites, in softening water, viii, 324 Zeppelin, Friedrich von, v, 225-6, 228, 382 Zeppelins, v, 225-6, 228-9, 382; development by Germany, i, 40; in World War, 310 Zero, invention of, xvi, 184 Ziczac, Egyptian, xii, 263 Zinc, affinity intensity, viii, 128; atomic weight and symbol, 383; extraction from ores, 270, 271; in electric cells, vi, 59, 61, viii, 167; in heavy metal group, 126-7, 154; melting point and requirements, iv, 162, viii, 384; occurrence and production, iii, 363-4, viii, 129, 198; specific gravity, 384; test for, 287, 289; uses, iii, 363, viii, 155-6; used in hydrogen preparation, 32-3 Zinc Carbonate, viii, 130 Zinc Sulphate, viii, 96 Zircon, iii, 341; axis ratio, 317 Zirconium, symbol and atomic weight, viii, 383 Zodiac, ii, 254 Zodiacon, i, 192 Zoetrope, v, 329 Zone of Flowage, iii, 84 Zone of Fracture, iii, 84; action of rocks in, 86 Zones, Climatic, earliest distinction, iii, 220; not marked in oldest times, 173, 178, 184, 202 Zones of Silence, i, 189-92 Zoögonidia, movements, xvi, 166 Zooids, xii, 34 ZOÖLOGY, Volume xii Zoölogy, binomial nomenclature in, x, 84; daily interest, xvi, 15-16, 22, 25-6; defined, xvi, 36; history of development, 116, 126, 140-8 Zoöpraxiscope, v, 330 Zorilla, xii, 348 Zuider Zee, formation of present, xiv, 45-6 Zulus, ideas of future life, xv, 333; musical instruments of, 317; polygamy among, 288 Zuni Indians, pottery-making by, xv, 250 (fig.) 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