title: Beacon lights of science, a survey of human achievement from the earliest recorded times,
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Vv « ■/. ^'v * mWm 2; ^ v « ^ *; ^ ^ <v\r# ^ ^TWT-v .rr ^ " • 0 ^ , ^ *,/’ ^ v ^^TTT'' A ,. „; <A. o°- .* v :-' . % o°- „ - ’ * “ ' . % C? . ; , . : V \ - - ° - ^ " - N '^ A1 -1 ^ c -q 5 ♦ $r ' °^ ", " vV ^ o ^ Cr o c 5 > y ^l> - ^ * » ■*» o ^ _ /• ^JujJ’-W \ •ot- % Oo” Oi ^ / t s .oA s \v 0 # ^ a * s \V \> ^ * * 0 A % V v * ' - «y ^ % s' <^' ‘ * * ' ' A » - 1 * °r ^ ' * ‘ ' / » ' * » f « A o. C V. O* I \ BEACON LIGHTS OF SCIENCE A SURVEY OF HUMAN ACHIEVEMENT FROM THE EARLIEST RECORDED TIMES BY THEO. F. VAN WAGENEN NEW YORK THOMAS Y. CROWELL CO. PUBLISHERS Copyright, 1924 By THOMAS Y. CROWELL CO. Printed in the United States of America SP 30 *24 ©Cl A808116 INTRODUCTION In the following pages the attempt has been made to sketch, in outline, the development of Science throughout the centuries, in the lives of those individuals who, in their time, have contributed notably to its progress. Naturally it has been impossible to include all who have taken some part in the great work. And also, many of the most promi¬ nent are still with us, their labors unfinished. To the young man preparing himself for a scientific career, or entering upon its duties and obligations, the efforts of those thinkers and discoverers who have passed on and left to him the rich heritage of knowledge so far ac¬ cumulated should be an inspiration and an incentive. Or, taking a lower view of the matter, he should at least know enough of their lives to be able to connect the discoveries with the discoverers and to have some conception of their personality. We cannot be too mindful of the difficulties with which they had to contend in their explorations in a field of mystery, where none before them had blazed a path. Doubtless there were true scientists before Euclid. But of them so little is certainly known, and with their dis¬ coveries so much of mysticism has been blended, that their stories come to us enveloped in a haze through which it is difficult to arrive at a fixed starting point. It is also hard to draw a line which shall clearly leave on one side the con¬ clusions of speculation, and on the other the logical deduc¬ tions from correctly observed phenomena. It seems clear, however, that the habit of collecting and classifying ob¬ served facts of nature (mainly astronomical) began with the Semitic people, and from them passed to the Aryans by way of that first intellectual flowering of its civilization, the Greeks. But the latter lived in an environment so beauti¬ ful, and possessed—probably as a result of it—a tempera- VI Introduction ment so aesthetic, that cold-blooded study of nature was un¬ congenial, and to all but a very few impossible. If the con¬ tents of the lost Alexandrian library could be restored in¬ tact and made accessible to the modern student, it would no doubt prove of surpassing interest, but probably also of little value to science. As the glory of Greece faded under the stern shadow of Roman dominion, about all that the latter inherited from it, in the way of real knowledge, was the beginnings of the science of mathematics. Rome contributed practically noth¬ ing in its day to the explanation of natural phenomena, though it acquired a vast amount of empirical information through experience in dealing with its forces. And when, through the revival of mysticism, the Dark Ages came on, enveloping all Europe in their gloom, Science slumbered and dreamed for centuries, while Astrology and Alchemy wore its mask, and posed on the stage in the tinsel gar¬ ments of a dead and forgotten past. It is difficult for us today to believe that in Europe, for more than a thousand years, the children who were born into the world were taught by their elders that there was but one true source of knowledge—religion—and that it was not only useless but impious to seek for the explanation of natural phenomena elsewhere. When at last revolt against this monstrous misconception began, Science awoke from its long sleep; at first—as before—in the form of a revival of interest in the fundamental branch of mathe¬ matics, which was quickly followed by renewed activity in astronomy and mechanics, the two departments whose manifestations were most readily open to observation. Once recalled to life, other departments of knowledge be¬ came recognized in turn as they appeared as true children of science, and worthy descendants of those few masters among the ancients who, brushing aside as unworthy of their time the delights of speculation, devoted their energies to observation, and to the drawing of conclusions from the marshaling and classification of well demon¬ strated facts, rather than from the processes of ratiocina¬ tion. Yet the paths of these pioneers were beset with dif- Introduction vu Acuities. Copernicus was proclaimed a heretic by both of the grand divisions of the Christian church, Galileo was compelled to recant on his knees, and Darwin of a much later time was called an atheist, though all were men of deep religious feeling whose lives were full of love and re¬ spect for their fellows. In arranging the order of these sketches, the life period has determined the sequence. With a few unimportant exceptions this brings to the reader in turn the different branches of knowledge as they were developed. Thus, with the exception of the early Greek studies in anatomy, mathe¬ matics, mechanics, and astronomy were the only sciences in existence up to the early years of the seventeenth century, when Mersenne, Harvey, and Gunter led the way with dis¬ coveries in acoustics, physiology, and magnetism. During the remainder of that period optics and physics were added. The eighteenth century witnessed the beginnings of the elec¬ trical, chemical, and geological sciences, and towards its close physiology and anatomy had become well founded on demonstrated facts. In the nineteenth century all these departments of re¬ search were greatly developed, and chemistry, the science of matter, easily took first place in importance, with physics a close second, and philology, embryology, meteorology, anthropology, ethnology, pathology, biology, and a host of minor “ologies” crowding upo^i the stage from the wings and demanding recognition. Towards its end, physics, the science of energy, displaced chemistry in importance, and at the present time is well in advance, while the thinkers of the world are reaching out into the new fields of psycho¬ physics and psychology in the hope—and the expectation —of being able to solve with their aid some of the mysteries behind those concepts of matter and energy whose laws and manifestations are now fairly well understood, but whose causes still remain unexplained. T. F. Y. W. CONTENTS I. ANCIENT TIMES PAGE Thales ""Primitive Theories. 3 Anaximander —Mathematics . 4 Pythagoras Astronomy . 5 Empedocles -Evolution . 8 Democritus -Natural Science . 9 Hippocrates -Medicine . 11 Plato -Philosophy and Mathematics. 12 Aristotle -Natural Science . 14 Theophrastus Botany . 17 Erasistratus Anatomy. 18 Euclid Mathematics . 19 Archimedes Mechanics. 21 Eratosthenes Astronomy .. i. 23 Aristarchus Astronomy . 24 Apollonius —Mathematics . 26 Hipparchus Astronomy . 27 Dioscorides Botany . 29 * Ptolemy Cosmology and Geography. 30 Galen Anatomy. 33 Piophantus Mathematics . 35 II. THE MIDDLE AGES Aryabhatta ""Astronomy . 41 Brahmagupta “Mathematics . 42 Al Khuwarismi- Mathematics. 43 Al Hazen -Mathematics. 45 Bhaskara - Mathematics. 46 Bacon Speculative Philosophy and Natural Science.. 48 Peuerbach Mathematics. 52 Muller (Eegio- Mathematics. 53 montanus) Da Vinci General Science . 56 Copernicus Astronomy . 58 Fallopius Anatomy. 62 IX X Contents 111 . THE SIXTEENTH CENTUEY PAGE Tartaglia Mathematics. 67 Yes alius "-Anatomy. 68 Gesner -^Natural History . 70 Eustacio Anatomy. 71 Fabrizio Anatomy. 72 Gilbert "-Natural Science . 74 Brahe Astronomy . 76 Stevin Mathematics. 82 Napier Mathematics. S3 Galileo Astronomy . 85 Kepler Astronomy . 94 Harvey Physiology . 99 Mersenne Physics . 101 Desargues Mathematics. 103 Descartes Mathematics. 104 IV. THE SEVENTEENTH CENTUEY Fermat Mathematics. Guericke Physics. Torricelli Physics. Pascal Mathematics. Boyle Chemistry. Cassini Astronomy. Malpighi Anatomy. Huygens Physics. Leeuwenhoek Microscopy. Hooke Physics. Newton Physics. Boemer Physics. Leibnitz Halley Mathematics and Philosophy... Astronomy. Bradley Astronomy. Maclaurin Mathematics. De Jussieu Botany. V. THE EIGHTEENTH CENTUEY Gray Chemistry. Bernouilli Mathematics. Franklin Electricity. Buffon Natural History ... Dinnaeus Natural History. Contents xi PAGE Euler Mathematics. 154 Clairault Physics. 156 D’Alembert Mathematics. 158 Hutton Geology. 160 Hunter "Physiology and Anatomy. 161 Black Chemistry. 162 Spellanzani -Physiology. 164 Cavendish Chemistry. 166 Priestley Chemistry. 167 Coulomb Physics. 169 -Watt "Mechanics. 171 Lagrange Physics. 173 Galvani Anatomy. 174 Herschel Astronomy. 175 Scheele Chemistry. 177 Hauy Mineralogy. 179 .Lavoisier Chemistry. 181 Lamarck Natural History. 182 Volta Electro-Chemistry. 184 Charles Aeronautics. 186 Monge Mathematics. 188 Bode Astronomy. 190 Werner Geology. 192 Berthollet Chemistry. 193 -Jenner Physiology. 195 Laplace Astronomy. 198 Legendre Mathematics. 200 Rumford Physics. 202 Proust Chemistry. 204 Prony Mathematics. 205 Chladni Physics. 207 Wollaston Chemistry. 209 Dalton Chemistry. 211 Cuvier Anatomy. 213 Humboldt Natural History. 215 Oersted Physics. 217 Brown Botany. 219 Young Physics. 221 Bell Anatomy. 222 Ampere Electricity. 223 Avogadro Physics. 225 Gauss Astronomy. 229 Davy Chemistry. 231 Gay-Lussac Chemistry. 232 Berzelius Chemistry. 234 Silliman Geology. 235 xii Contents PAGE Audubon -Natural History. 237 Brewster Physics. 239 Bessel Astronomy. 241 Dulong Chemistry. 242 Chevreul Chemistry. 243 Arago Astronomy. 245 Fraunhofer Physics. 247 V Ohm Electricity. 248 Fresnel Physics 250 Daguerre —Photography. 251 Faraday Electricity. 253 Yon Baer Embryology. 255 Lobatchevsky Mathematics. 258 Weber Physiology. 259 Sadi-Carnot Physics. 261 Lyell -Geology. 263 Henry • Electricity. 264 VI. THE NINETEENTH AND TWENTIETH CENTURIES Dumas Chemistry. 269 Wohler Chemistry. 271 Muller Physiology. 273 Abel Mathematics. 275 Wheatstone ' Physics. 277 Doppler Physics. 278 Liebig Chemistry. 279 Maury Geography .... 281 '—Agassiz Geology. 282 Guyot Geography. 284 Darwin Biology. 286 Forbes Physics. 287 Gray Botany. 289 Andrews Chemistry.. 291 Draper Chemistry. 293 Leverrier Astronomy. 294 Bunsen Chemistry. 295 Pacini Physiology. 297 Dana Natural History. 298 Bernard Physiology. 300 Yon Mayer Physics. 301 Angstrom Physics. 303 Hooker Botany. 306 Joule Physics. 307 Foucault Physics. 309 Contents xiii PA6E Adams Astronomy. 310 Stokes - Physics. 311 Tyndall Physics. 313 MtiLLER Biology. 315 Helmholtz Physics. 316 Virchow “-Pathology. 318 Galton -Biology and Physics. 320 Wallace —Natural History. 321 Mendel Biology. 324 Clausius Physics. 325 Pasteur Bacteriology. 327 Leidy Natural History. 328 Fabre Natural History .«-331 Hittorf Physics. 334 Kirchoff Physics. 336 Thomson Physics. 337 Broca Anatomy. 339 Huggins Astronomy. 340 Schulze Biology. 342 Bates Natural History. 343 Huxley Biology. 345 Buckland Natural History. 347 Berthelot Chemistry. 349 Lister Medicine. 351 Kekul 6 Chemistry. 353 Marsh Natural History. 354 Maxwell Physics. 357 Tylor Biology. 358 Crookes Physics. 360 Nobel High Explosives. 362 ‘Lubbock Natural History. 364 Weismann Zoology. Thirty-seven world scientists were chosen, only two of whom were American. Hippocrates, Aristotle, Archimedes, Copernicus, Vesa- lius, Harvey . Frontispiece PAGE Galileo, Leonardo, Hipparchus, Euclid, Democritus, Thales . 70 Carnot, Bernard, Joule, Pasteur, Mendel, Maxwell.... 140 Humboldt, Dalton, Lamarck, Watt, Franklin, Huygens. 210 Descartes, Newton, Linnaeus, Lavoisier, Laplace, Cuvier, Gauss. 290 Galton, Gibbs, Helmholtz, Darwin, Lyell, Faraday 380 I ANCIENT TIMES For the purpose of this volume it will be convenient to define its first department (Ancient Times), as the epoch extending from the beginnings of recorded human history, up to the fall of the Roman Empire in the year 476 of the present era, a period covering certainly 6000 years; for inscriptions that are clearly alphabetical in their character appear on many of the Egyptian and Chaldean monuments, whose age has been determined as early in the 5th millennium b.c. And before them for an unknown time were the years of hieroglyphs. But we may safely deduct at once at least four millenniums from this reckoning, as a period during which the art of writing was confined wholly within the priestly class, and employed only to record the principal acts of rulers, or startling occurrences like famines, floods, eclipses, etc. And about as safely another thou¬ sand, for the slow development of a script convenient enough in execution, to permit of the recording of conclusions arrived at by observers of those natural phenomena that were daily presented to the senses and minds of the civilized people among the ancients. This brings us down to a date somewhere between 750 b.c. and 500 b.c., at which time appeared Thales of Miletus, the first of whose story enough is known to warrant his inclusion in a list of scientists—that is, of collectors and classifiers of observed phenomena’, apparent or real. Certainly there were students and scholars before his day, for by then much true knowledge of various kinds had accumulated, but their names and their histories have been lost. During the eleven hundred years remaining of the period, namely, from 624 b.c. to 476 a.d., history has preserved less than a score of names worthy of enrollment as 11 Beacon Lights of Science. ’ 7 It is a significant fact that, of the total number, sixteen belonged to the Greek race, the other two, Thales and Ptolemy, being re¬ spectively of Plioenecian and Egyptian ancestry or birth. And, as showing the versatility of Hellenic culture, four of these attained eminence in mathematics, four in astronomy, two each in botany and the healing art, one each in general philosophy, mechanics and anatomy, while to Empedocles must be accorded the supreme honor of having formulated the first known conception of the theory of evolution. BEACON LIGHTS OF SCIENCE THALES (circa 624-560 b.c.) PRIMITIVE THEORIES Thales is reputed to have been a native of Miletus, a very famous ancient Greek city located on the western coast of Asia Minor at the mouth of the Maeander river. By race he was of Phoenecian ancestry. He seems to have been possessed of engineering capacity, for he was en¬ gaged to construct an embankment along a portion of the shores of the river Halys.. He was also a merchant of importance, and traveled extensively, particularly in Egypt, where he became familiar with such astronomical and mathematical knowledge as by then had accumulated among the priesthood. In consequence, upon his return to Miletus, he was able to predict an eclipse of the sun, which actually occurred in the year 585 b.c., and acquired thereby a great reputation. Being a man of wealth and leisure he decided to devote the balance of his life to philosophy, and was regarded either then or later, as one of the six or seven wise men of ancient Greece. He taught that the fundamental element of which all things was composed was water. That the earth floated upon it; that it was the cause of earthquakes and volcanos; that it was the main component of all vegetation—which apparently could not exist without it; of all animal life that lived on vegetable food, and hence by necessity, of all flesh-eating animals, including man. According to some of his commentators he regarded earth (soil and rocks), air and fire as also of elementary character, though of 3 4 Beacon Lights of Science secondary importance. He is credited with having be¬ lieved that the earth was of the form of a sphere, and that the year consisted of exactly 365 days. He expressed his views in words only and committed nothing to writing. Thales, whether a real or a legendary character, repre¬ sents the beginnings of Greek intellectual life. Before his day much information about the ordinary phenomena of life had been gathered in Egypt, Chaldea, Phoenecia, and to a lesser extent in India and China. But life was hard and unlovely among all those people, for they occupied regions where climatic conditions were severe, and the struggle for existence a pitiful one, except for the favored few. To the Greeks, however, had been given a pleasanter homeland, a more genial climate, and an environment that encouraged thoughtfulness and a desire to understand the causes of things. As their civilization advanced, a very considerable percentage of the mass of the population lived in comfort and comparative luxury. Out of such condi¬ tions arise appreciation of the beauties of nature, and a desire to produce beautiful things, in other words, the fine arts. Also a tendency to speculate about the mysteries of life and the universe, but without any observational foundation. These were the impelling and prevailing ten¬ dencies in Grecian life until the time of Aristotle (about 350 b.c) , who taught a more correct way of looking at things. ANAXIMANDER (610-546 b.c.) MATHEMATICS Anaximander was bom at Miletus, one of the populous and famous ancient cities of the western coast of Asia Minor. Very little is known of his personal history be¬ yond the fact that he became, after the death of the philosopher Thales, the head of the Ionian school of Greek thought. Aside from the reputation which this position brought to him, he is generally credited with having been the first among the ancients to proclaim that the axis of Ancient Times 5 the earth must be inclined to the extent of about 23 degrees to the plane in which it stood (or moved) with respect to the sun. In other words, he taught as a fact the phenome¬ non we now call the obliquity of the ecliptic. Yet there is no clear evidence that he had any true conception of the shape of the earth, of its revolution on its own axis, or of its annual journey around the sun. Yet he is believed to have been the inventor of those old astronomical de¬ vices the gnomon and the polos. The views of the cosmos held in his day were full of strange contradictions. It is difficult to believe that a mind capable of reaching so close an approximation to the cause of the annual change of seasons, and of producing an instrument capable of indicating divisions of time by the changing positions of the shadow it cast, could have been wholly unacquainted with the causes behind these results. But, as was the case with most, if not all of the Greek philosophers, Anaxi¬ mander seems to have held and taught, along with a few correct facts of Nature, many others that now seem ab¬ surd. For instance, his conception of the Universe appears to have been that of at least three concentric transparent and revolving cylinders, to the outer one of which the sun was firmly fixed, while the middle one carried the moon, and the innermost one the stars. Within these was the earth, also cylindrical in form, and either stationary or moving with the others. He was uncertain as to the posi¬ tion of the five planets then known. On the other hand, according to some of the ancient writings, he made some excellent approximations of their size and relative dis¬ tances from each other. PYTHAGORAS (c. 580-500 b.c.) ASTRONOMY Such accounts as have come down to us of the life and activities of this traditionally famous Greek, are not at all clear, and much is plainly pure myth. He appears to have been a native of Samos, an island off the west coast 6 Beacon Lights of Science of Asia Minor; but of his ancestry and of his youthful years we have no reliable information. In his early ma¬ turity he appeared in the city of Cretona, in the southern part of Italy, which at the time was the seat of a Grecian colony. Here he founded a society or brotherhood, of the nature of an intellectual autocracy, which later took on a political cast, and became deeply involved in the fierce struggles then in progress throughout the Grecian world between democracy and plutocracy. In the end the few Pythagoreans who survived were driven from the country. It is not known whether Pythagoras escaped before the culmination of this event, or perished in it. Whichever was the case, Pythagorism represented subsequently some very strange conceptions of the Universe, which have come to us through contemporaneous and subsequent writers, but so alloyed with fable and nonsense that students of Grecian history and thought have found it very difficult to decide with any degree of certainty much more than the outline of his teachings. Not a word that could be safely ascribed to him personally has been preserved, and of the writings of his disciples we have only fragmentary re¬ mains. From these, and from later writers, two of the more startling of the tenets of the cult appear to have been as follows: As to the substance of the world, they conceived it to be composed of material atoms, each one of which was so infinitesimally minute as to represent position only, without size. Two, side by side, expressed a line and conveyed the idea of direction, but again without magnitude. Three (one being at right angles to the other two) ' indicated surface, but without thickness, thus being merely the rep¬ resentation of area or extension; while four (the fourth at right angles to the other three) constituted a solid, or the conception of Form. Thus the three-dimensional prop¬ erty of Space was reached and explained. It was regarded as unlimited in extent, and filled with air, or, according to others, a void. As to the atom, if it were of earthy matter it was believed to possess the shape of a cube; if of fire, that of a tetrahedron or three-sided solid; if of Ancient Times 7 water, that of an icosahedron or twenty-sided figure, while those of all other substances were twelve-sided masses. Out of all this rubbish the only item of importance is the conception of the atom as the ultimate component of mat¬ ter. In regard to the external Universe, the Pythagoreans taught that at its center there was a source of light and heat in the shape of a perpetual and intense fire, and that all the heavenly bodies—including the earth—revolved around this in concentric circles at various distances apart. That the earth was the nearest to this source, and made its revolution in such a way that one of its hemispheres always faced this source (just as one face of the moon only is presented to the earth), and was necessarily uninhabit¬ able, on account of its intense heat. All the other celestial bodies shone by reflected light only, the earth obtaining its share by reflection from the largest of them, the sun. When the earth is on the same side of the central fire as the sun the phenomenon of daylight exists. When it is on the opposite side, that of night supervenes. These examples of Pythagorean philosophy are suffi¬ cient to show that its founder and his disciples were people gifted with vigorous imaginations, but poorly equipped with demonstrated facts; just such a combination as might have been expected of the lively and speculative Greek mind at that age of the world; so different in its nature from that of the still older Egyptians and Babylonians, each of whom developed theories of the Universe of a very different kind. Whether Pythagoras ever existed as an individual, or whether the name simply stands for a system of philosophy having for its object to account for the innumerable mys¬ teries of existence, the cult very properly takes its place among the beginnings of science for, in spite of the mass of error it stood for, here and there appear conceptions and conclusions that have since been demonstrated as re¬ alities. 8 Beacon Lights of Science EMPEDOCLES (495-435 B.C.) EVOLUTION This Greek philosopher was bom of a distinguished fam¬ ily whose home was in the city of Agrigentum in Sicily, when that island was a Grecian colony. In addition to having attained a high standing as a physician, he is re¬ garded as one of the notable philosophers of the ancients. He also appears to have been a strong advocate of certain political doctrines of a democratic tendency, which he en¬ deavored to put in practice in his native city. Very little reliable information of his life has been preserved, but many marvelous stories have come down to us relating to his beliefs and ideas, and to his powers as a physician. The most of these are simply exaggeration, though perhaps based on real facts of a less startling nature. Of the manner of his death several tales are told. The most com¬ mon was to the effect that he leaped into the crater of Mt. Aetna. Another states that he experienced translation, after the manner of the Jewish prophet Elijah. He is said to have performed several miracles, one of which was to bring back to life a young girl long dead; and another to avert from Sicily a pestilence raging in southern Italy, by compelling a change in the direction from which the wind was blowing. Amid all this legendary nonsense it seems to be a fact that he was one of those early thinkers who had grasped some germs of the idea of evolution, in his endeavor to account for the mysterious phenomena of the Universe. Aristotle was another. With Empedocles the theory took form in the saying that “Nature produces those things which, being continually moved by a certain principle contained in themselves, arrive at a certain end.” To connect the rather obscure meaning of this sentence with the modern doctrine of evolution requires some knowledge of the brand of philosophy he represented. He held that “Being,” by which he meant Matter, was eternal and im¬ perishable. He considered it to be of four kinds or ele- Ancient Times 9 ments mutually independent, namely, earth, air, fire and water. He maintained the existence of two fundamental and opposing forces, which he typified as Friendship and Strife; the first of which was the indwelling and normal principle, and the second the external and abnormal one. These two, in their perpetual conflict, the one to maintain the status quo and the other to change it, produced all the phenomena of nature. He held that these changes were constantly and imperceptibly occurring, and had been throughout unknown ages in the past, with the effect of steady progress upward in all phases of existence. Finally, that man was, at the present, the highest product of the process. In thus indicating that the principle he called Strife—by which perhaps he intended to convey the idea of competition for existence or supremacy—was always in the end victorious, he may have grasped the germ of the idea at the foundation of Darwinianism, the survival of the fittest. With Empedocles chance, or acci¬ dent was the cause of the successes of Strife over Friend¬ ship. Aristotle rejected this as of the nature of an impiety. DEMOCRITUS (circa 470-400 b.c.) NATURAL SCIENCE This notable Greek, whose birthplace was the ancient town of Abdara in Thrace, went by the name of “The Smiling Philosopher 9 ’ among his intimates, because of the geniality of his disposition and his optimistic temperament. About all that is known of the details of his life is that he was a man of high moral character and strong religious tendencies, was well educated according to the standards of the time, was deeply interested in mathematics and astronomy, wrote extensively on these subjects and on philosophy, and had traveled through much of the civilized world of his day. Only fragments of his writings have been preserved. These were collected and published by Mullach in Berlin in 1843. From them, aided by references in, and commentaries by other writers—both Greek and Latin, it 10 Beacon Lights of Science has been possible to deduce the general system of philoso¬ phy which he held, and probably taught. It was based on a theory of that aspect of matter which the mind receives from the five senses, the essential nature of which has been considered, until recently as unknowable; but which now seems to have been resolved into one of the manifestations of the equally unknowable entity we call Energy. In his system a material atom was postulated, infinite in multitude, not all of one size or kind, but each endowed with the power of motion, and the ability to unite into aggregates of all dimensions, forms and quantities, under certain pre-ordained laws; some of which eventuated in the phenomenon of life, and others in static con¬ ditions, which were apparent in those manifestations like rocks and metals, which plainly lacked the vital quality. For these reasons his philosophy was known among the Greeks as the Atomic System. To Democritus therefore belongs the credit of having first conceived the idea of the material atom. To what the theory led, and what speculative structure he reared upon its foundation, is not clear. He denied the existence of Design in the Cosmos, but asserted that of immutable law. Animals, vegetation, moving air and water, he regarded as combinations of atoms of average quality. Consciousness and thought the product of the coming to¬ gether of particles of a finer kind. And he postulated the existence of a third and superior class, of which the sub¬ stance of the High Gods was composed. Happiness he considered as the supreme object of existence. To attain it, the passions must be controlled, and temperance made the rule in all departments of life. As to a possible future stage of being, he seems to have had no theory. It is thought by some students of the Greek mind that Epicurus (circa 324-270 b.c.) was a believer in his philos¬ ophy, and taught it, with probably some amplifications of his own. According to him, fear of the Gods and fear of death were the two great destroyers of human happiness, and the main objects in life were to overcome these terrors, by rising superior to them. Believing that Personality Ancient Times 11 ended with death, he argued against looking to the future for any amelioration of present condition; insisted that life was wholly an affair of to-day, that it was beautiful, that it was the summit of wisdom to enjoy its gifts as they came, but always temperately, and with consideration for others. He thought that the gods were imperishable, and could have nothing to do with us, inasmuch as they lived on a different plane. If these were also the ideas of Democritus, they were rather above the average of the time, but have little value for the present. HIPPOCRATES (circa 460-375 b.c.) MEDICINE Hippocrates, the most celebrated Greek physician of his time, who is called the Father of the Medical Art, was claimed by his contemporaries to have been the seventeenth or nineteenth in direct descent through his father from the mythical Aesculapius, and through his mother from the equally mythical Hercules. He was a native of Cos, one of the Aegean isles, where he practiced his profession, and was at the head of the medical school there until old age compelled retirement. Much of his supposed history is undoubtedly fabulous and unreliable, but that he was an unusual man for his time, and held some very advanced views in anatomy, and on the treatment of diseases, can hardly be denied. The latter, broadly, took the form of a strong reliance on the forces of nature, and on the power of the body itself, to eliminate or overcome disorders even of a serious kind, if aided by proper regimen and improved environment. With this was coupled an equally strong disinclination to interfere with the normal functions of the organism by the administration of drugs. Thus, he often prescribed merely a change of climate, or an altered and limited diet, or the securement of conditions that would provide absolute quiet and long hours of sleep. Frequent bathing of the entire body, sometimes in cold, and at others in warm or hot water, was also a favorite method adopted. n Beacon Lights of Science It was probably this very sensible system which, as is now well known, will cure a very large percentage of human bodily ills, that brought him the high reputation accorded by his contemporaries. The writings that bear his name are seventy-two in number, but many of them are now ascribed to his sons, Thesalus and Draco, and his son-in-law, Polybus, all three of whom were his assistants in his practice. The fifteen to twenty that are considered actually his are marked with a sanity of view and an absence of mysticism unusual for his age, and point to the conclusion that his reputation was well earned, though probably not so astonishing as some biographers of his time and since would have us believe. PLATO (427-347 b.c.) PHILOSOPHY AND MATHEMATICS The real name of this Greek philosopher was Aristocles. He was a native of Aegina, a small island just off the southeast coast of Greece, and a dependancy of Athens. His parents were large land owners of the upper class, and in consequence he was given the best education that the times afforded, the most of which was absorbed at the Lyceum conducted by Socrates. Of the details of his life little is known, but according to tradition he distinguished himself as a youth in athletics, and was a composer of poetry. But none of his productions in this line has been preserved, for at the age of twenty he became so interested in the philosophy of his great teacher, that he is said to have burned them as unworthy. He was so affected and even embittered against the authorities of the time at the judicial murder of Socrates, that it is thought he left Athens shortly thereafter, and spent the following ten to twelve years in travel in northern Greece, southern Italy, Sicily, Libya and Egypt, in the search of a civilization 'where more liberal and friendly and honest conditions pre¬ vailed. Of the truth of this quest there is no clear evi- Ancient Times 13 denee, but in the year 387 b.c. he was again in Athens, at the head of an organization called the Academia, which held its meetings in a public garden or grove outside of the city, that formerly had been a semi-sacred place, dedi¬ cated to the memory of a mythical hero named Academus. There, for forty years, and until his death, Plato taught, and discussed with his pupils the questions of the day and, as was the custom of the time, instructing them during the periods of recreation in athletics, on the theory that the body and mind should be developed together. Among his more famous pupils were Aristotle, Demosthenes, Lycurgus the financier and Eudoxus the astronomer. It is believed that Plato exercised unusual care in admitting students to his lectures, and refused to take pay from them, on the theory that Truth should be imparted freely to all who were earnest seekers after it. His standing as a scientist rests primarily on the well- attested fact that, for his day, he was a mathematician of a high order, though not a discoverer of any new prin¬ ciples in numbers, or the developer of any new system of working with them. Nor did he teach it directly. In fact no one was allowed to attend his classes who had not already become fairly proficient in the science. Regard¬ ing it as the one department of knowledge in which certi¬ tude of result could be obtained where correct premises had been employed, he endeavored to lay the foundations of a system of philosophy which could be depended upon with equal confidence. In this he attained a certain degree of success, yet by no means a complete one. For, though we can today read much of his writings with advantage, and admit the possibility of some of his conclusions, the best thought of the world at present is to the effect that certain conceptions of which the human mind is capable are scientifically unknowable, in the sense that their parts cannot be assembled, classified, grouped and organized into a coherent body of demonstrated fact, that can be relied upon as long as it continues to be satisfactorily explana¬ tory of observed phenomena. In a day when polytheism was the accepted religion of 14 Beacon Lights of Science the educated, Plato taught what may be described as a pure theism, that is, belief in a Deity related closely to all living things, vegetable, animal and human, but at the same time he made no attempt to define the nature of the relationship and, in fact, asserted that definition was im¬ possible. Beyond this in religion he did not go. But in ethics he felt justified in going to great lengths. Plato wrote very extensively. But much has been lost, and much that was originally credited to him is regarded as spurious by present-day students. Rejecting the latter, the fundamentals of the philosophy he taught seems to have been about as follows: Truth is hard to find, and in many cases impossible; but it is wise to discuss it in all its aspects because, by such a treatment, much of error can be avoided. As to conduct, which he called the * ‘ Royal Art,” he re¬ garded it as a science, which must be learned through experience, just like a material art, as carpentering. Its basic principle, self-sacrifice when necessary, once grasped, must be obeyed relentlessly to the end. Plato was inherently a metaphysician, and metaphysics is regarded today as a diversion, which leads nowhere, and to nothing except temporary mental amusemeift. In other words, it is not common sense to the average human mind as at present constituted. As it may with reason be as¬ serted that individual mentality has evolved to a higher state than was existent among the Greeks, his philosophy can be admired as among the most advanced of that time, his ethics can be commended whole-heartedly, but many of his conclusions should be recognized as adolescent in char¬ acter, and below the standard which should be held now. ARISTOTLE (384-322 b.c.) NATURAL SCIENCE The distinguished thinker, Aristotle, was a native of the ancient Greek city of Stagira, which was situated on that curious three-pronged peninsula projecting into the Aegean Ancient Times 15 sea to the south of the present city of Saloniki. In olden times the region was a part of the kingdom of Macedonia. He belonged to an aristocratic and wealthy family in which learning had been hereditary for many generations, his father having been court physician to King Amyntas II. He received the best education that the times could afford. At the age of seventeen he went to Athens and associated himself with the school of which Plato was the head, and studied under that great teacher for nearly twenty years, becoming towards the last one of his chief assistants. 