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.