342 SCIENTIFlCAMERICAN. SUPPLEMENT Na 2265 May 31,1919

The Influence of Astronomy on H uman Thought* The Study of the Universe In its Role as the Science of Infinite Space and Infinite Time By Rev. Hector Macpherson

ASTRONOMERS are sometimes called "star-gazers" j and world-concepts in plenty, but these world-concepts were venting the famous theory of epicycles, which super­ the word, though often playfully applied, has in it It not the result of observation. They were guesses at the seded the hypothesis of Eudoxus. The idea of concen­ certain suggestion of pity, if not of contempt. It is riddle of the universe, a jumble of pagan theology and tric spheres was abandoned. Sun, moon, and stars were usmUly applied by those who know just enough of astrological superstition. 'I.'he Hebrews and the Greeks assumed to be in motion round the earth in circular astronomy to know that there is in its cultivation an were, in the things of the spirit, the greatest races of orbits. But some explanation had to be given of the unworldly and idealistic motive, and too little of the antiquity and to them fell the task of separating re­ irregularities of the celestial motions. In essence, the science to realize its great practical and intellectual ligion from science. The Hebrews, who had little or systems of Apollonius, Hipparchus, and Ptolemy were benefits,-indeed, its necessity to the human race. no interest in natural science, disentangled religion identical, but the latter worked the epicycle theory to Those of us who have studied and followed the science from crude naturalism and pseudo-science, while the its fullest perfection. Thus the astronomy of the day realize that it is by means of astronomy that latitudes Greeks were the founders of actual scientific observa­ gave credence to the belief that the earth was the and longitudes are determined, and extensive naviga­ tion, and based their theories on actual fact. center of the universe, and man the crown of creation. tion made possible,-that it is by means of astronomy Of course, it is impossible to draw hard and fast lines Ptolemy was the last great name in ancient astron­ that land-surveys can be carried out and accurate time between various races. The transition from the pseudo­ omy. In his great work, the "Syntaxis," which came determined. These are the most obvious practical uses science of the Babylonians to the careful observation of to be known by its Arabic name of the "Almagest," of the oldest of the sciences. the later Greeks was a gradual one. '.rhus Homer and were summed up the results of the ancient Greek as­ "The student of astronomy," the late Professor Hesiod give us some idea of the similarity of the early tronomy. There was an air of finality about his great Young once remarked, "must expect his chief profit to Greek, ideas of the world to those of the Babylonians book. He was himself the last great astronomer, for be intellectual-in the widening of the range of thought and other ancient peoples. And the Ionian school of the great days of science seemed to be at an end. The and conception." There is a danger, in emphasizing philosophers, important and sagacious .as were their Hellenic culture had largely exhausted itself; an air the practical necessity of astronomy to the world, of theories and guesses, still followed a deductive method. of hopelessness and futility had settled over the world, forgetting the part played by astronomical science in They framed theories with little or no observations of and the Stoics rather concerned themselves with prob­ the development and progress of human thought-on natural phenomena. And so even in the period of the lems of conduct than with questions concerning the the world on which we live and the universe of which greatest triumphs of Ancient Greece, we cannot truth­ natural world; while the early Christians, expecting it forms a part. It is to the influence of astronomy on fully talk of the influence of astronomy on human the early return of Christ, did not busy themselves human thought that I desire to direct your attention thought. The influence was slight, for thought was a with the affairs of this world. Accordingly, slowly but this evening. priori and theories were deductive. surely, science and philosophy alike seemed to die out. It is a wide sub�ct, and in dealing with so wide a With Eudoxus of Cnidus, the cosmology of the Greeks When the Emperor Justinian suppressed the Neoplaton­ subject, it is necessary to be as concise and definite as entered on a new phase. With all his limitations, ist Schools in 529, he merely gave legal expressions to possible. So I shall deal with the subject in two gudoxus may be described as the first investigator of an accomplished fact. 'I.'he long night of the so-.called parts, which may be roughly classified as (1) cosmo­ cosmological problems from a purely scientific stand­ "dark ages" had begun. logical, and (2) cosmogonic. An American scientist in point. The earlier philosophers had proceeded on the As the church grew more and more powerful, as it a popular work used the phrases, "the extension of the ground of reason alone. Their method' was deductive. became gradually not so much the Christian Church as Universe in space," and "the extension of the Universe Eudoxus, on the other hand was an inductive thinker. the Church of Rome, the ptolemaic world-view was ill time." I shall take these phrases to designate the First and foremost he was an observer of the phenom­ stamped with the approval of ecclesiastical authority. two parts of my lecture. ena of the heavens, and, to explain these phenomena, And so, for hundreds of years, this remarkable system he advanced his famous theory of homocentric spheres. held sway over the minds of men, and was used to THE EXTENSION OF THE UNIVERSE IN SPACE. Whether the theory was ever more to him than a support and demonstrate the Roman Catholic view of From the earliest times, the human mind has been convenient working hypothesis is uncertain. Dr. Dreyer, life. confronted by the great problems presented by the nat­ who has made a close study of the Eudoxian theory, THE COPERNICAN REVOLUTION. ural world. The name of the first actual students of believed that Eudoxus only regarded his spheres as nature must remain forever in obscurity. It is tol­ "geometrical constructions suitable for computing the With the coming of the Renaissance, the minds of erably clear, nevertheless, that astronomy is the oldest apparent paths of the planets." Be this as it may, the men were once more turned to intellectual things. A branch of science, because the heavenly bodies are the theory, complicated and cumbersome as it was, ac­ number of men of scientific tastes arose,-such as Nich­ most prominent of natural objects. The early ob­ counted fairly well for the observed celestial motions. olas of Cusa, Pur bach and Muller, better known as servers of nature must have noticed the phases of the If there is a possibility that the theory was merely a Hegiomontanus. These men, however, remained faith­ moon and the changing aspect of the starry skies, and theory to Eudoxus and his pupil Calippus, who im­ ful to the orthodox Ptolemaic theory. And when the later, the fact that the sun varies in its altitude above proved and extended it, it was a great deal more to famous system of Copernicus was first propounded, it the horizon. Aristotle. In fact, it formed the basis of that great came on the world as a bolt from the blue. It is diffi­ In all probability, this kind of knowledge grew up philosopher's world-concept, and in estimating the in­ cult for us of today to realize the magnitude of the simultaneously among various peoples. There are tra­ fluence of astronomy on human thought, it must not scientific revolution which Copernicus initiated. From ditions of early astronomers and astrologers in China, bp forgotten that the astronomy of the day formed the time immemorial, all,-except, perhaps, a few irrespon­ in India, and in Egypt and in Babylon, for early as­ scientific basis of the theory of man and the universe sible thinkers among the Greeks, such as Hicetas and tronomy was inextricably mixed up with astrology and which held sway for so many decades and centuries Aristarchus, whose names were unknown save to the religious ceremonial, and thus the priests of the an­ over the human intellect. To Aristotle, the spheres learned few,-had believed the earth to be the center cient religions were in many cases the pioneers of as­ were actually in existence, portions of the vast mechan­ of the universe, the end and aim of creation. Only the tronomical observation. ism of the universe. He found it necessary to add earth was inhabited, and for the earth's inhabitants An intelligent study of nature is almost invariably twenty-two extra spheres. Calippus had assumed the the other bodies in the universe had been created,-the accompanied by what is called a cosmology or world­ existence of thirty-three, so that, as left by Aristotle, sun to give light and heat to the earth, and the moon concept. The mind of man, even in primitive condi­ the system comprised fifty-five separate spheres. Aris­ and stars to be convenient secondary light-givers in tions, is not content with knowing things as they seem totle as we all know, adopted the belief in the spherical the absence of the sun. This conception had been taken to be j it desires to know things as they are, and to form of the earth, and gave to it the weight of his up by the Roman Church, and by the Scholastic phi­ penetrate behind the veil of appearances. The human great authority. losophy. Little wonder, then, that the appearance of mind ever seeks a world-concept. Thus, even in very It is somewhat remarkable that while more and more the great work of Copernicus in 1573 caused no small primitive times, men formulated theories of the natural stress came to be laid in philosophical and speculative stir. At first, it was treated by the authorities with order and of the relation of the earth, our dwelling circles on Aristotle's opinion as to immobility of the contempt, and then with furious vindictiveness. Co­ place, to the outside world as a whole. earth, the astronomical theory on which he based his pernicus himself was beyond the reach of popes and Every ancient people had its cosmology or concept of hypothesis,-the spheres of Eudoxus,-was soon dis­ priests, for he survived only until the day of the pub­ the order of the world, and accompanying this, its cos­ carded. The progress of practical astronomy, by dem­ lication of his great work. It soon became apparent, mogony, or theory of the world's origin. That these onstrating its inadequacy, hastened its rejection. The however, that he was but a voice crying in the wilder­ early ideas were crude and fantastic is not to be won­ necessity of regulating time, the need for an accurate ness. When Copernicus died, the Reformation strug­ dered at. The late Professor Pfleiderer pointed out calendar, had stimulated observation of the sun and gle was at its fiercest. Yet Protestants vied with Ro­ that among early peoples "cosmogony is at the same moon, and this in turn influenced other branches of man Catholics in denouncing a theory which they felt time theogony," and we might also say that cosmology astronomy. At Alexandria, under the patronage of the to be subversive to the true faith. Luther referred to is at the same time theology. To the early peoples, dynasty of the Ptolemies, a school of astronomy was Copernicus as "an upstart astrologer, who strove to nature was full of deities, gods of land and of sea, of founded, and systematic observation of the heavenly show that the earth revolves." "This book," he con­ sun and stars, of storm and tempest. Both religion hodies was made. As Dr. Dreyer has well remarked, tinues, "wishes to reverse the entire science of astron­ and science were born of a crude cosmo-theology,­ "Vague doctrines and generalizations were abandoned, omy, but sacred scripture tells us that Joshua com­ largely the product of wonder and fear. while mathematical reasoning founded on observation manded the Sun to stand still, and not the Earth." The early races, Chinese, Hindus, Egyptians, and took their place. That this change occurred about the l\Ielancthon went so far as to suggest the forcible re­ Babylonians, seem to have made considerable progress middle of the third century (B. C.) was a circumstance pression of such views. The struggle became fiercer in astronomical observation, but they never got be­ not unconnected with the simultaneous rise of the and fiercer. The advocacy of the new view was one yond this confusion of theology and science. Many of school of Stoic philosophy. Both in abstract philoso­ or the charges on which Bruno was condemned to death the empirical facts of astronomy were noted and re­ phy and in science, the wish to get on more solid ground and burned at the stake in Rome in 1600. The second corded by them. The five planets were known to these now became universal, and no science benefited more "martyr" of the Jesuits was harassed and persecuted races, and the paths of sun and moon laid down. In by this realistic tendency than astronomy." solely for his adhesion to the Copernican system. In­ short, a large number of interesting facts were ascer­ To Apollonius of Perge is due the distinction of in- deed, it was in the course of the contest between tained, but there the achievement ended. There were Galileo and the Papal authorities that Copernicariism �A Parmenides it is true, had guessed the great truth of was finally condemned. We are all familiar with the *Read before the British Astronomical Association, West of the spherical form of the earth and this was accepted by Scotland Branch Reproduced from Popular Astronomy. IDudoxus. story of the struggle, how Galileo discovered the spots

© 1919 SCIENTIFIC AMERICAN, INC. May 31,1919 SCIENTIFIC AMERICAN SUPPLEMENT Nn 2265 343

on the sun, the satellites of Jupiter, and the phases got beyond the idea of the world-system as a great me­ imagination cracks." Herschel's epitaph in the church­ of Venus, thus weakening the ptolemaic system and chanism. As Ferguson remarked,-"That the projectile yard of Upton, near Windsor, claims that "he broke confirming the Copernican. Each of these new dis­ force was at first given by the Deity is evident." through the barriers of the skies." It is no exaggera­ coveries was doubted, disbelieved, and minimized. But Men such as Ferguson, Paley, and Thomas Dick would tion to say that this is true. He revealed to mankind with all their furious bigotry, some of these Roman have been the first to repudiate the charge of Deism, a universe of almost inconceivable vastness, ruled over theologians saw clearly the essential influence of the and rightly so. Yet the mechanistic conception of the by the law of gravitation. Compared to the extension Copernican system on human thought. After all, the universe, prevalent in the eighteenth century, had a of the universe in space which we owe to Herschel and vital point of the new doctrine was not an increased profound infiuence on higher thought, inasmuch as it his immediate successors, the Copernican revolution number of celestial bodies or the existence of moun­ prepared the way for Deism and commended it to the seems a very small affair. tains in the moon and spots in the sun. It was the rational faculties. In the writings of the popularizers THE EXTENSION OF THE UNIVERSE IN TIME. fact that the earth was no longer the centre of the uni­ of Newton, we find a constant emphasis on design, verse. Grant the truth of the Copernican system, and contrivance and impelling power. There was a latent This was by no means the sum of Herschel's work in the whole outlook on the universe is changed. As the Deism in this cosmological concept, as is obvious from astronomy, not only did he reveal greater vistas in earth is no longer the only world, so man's supremacy the remark commonly credited to Laplace,-"I have space, he likewise had a share in the development of becomes less certain. Boundless possibilities are opened no need of the hypothesis of God." cosmogony. up. The greatness of Copernicus is not to be measured Every ancient cosmology included a cosmogony. The HERSCHEL AND HIS WORK. by what he did, but by what he made possible. A early Greek thinkers undertoook to explain not only the vast extension of the universe was revealed; and so The rise of the elder Herschel marked another great construction of the world, but also its origin. With the philosophic and theological outlook was vitally af­ epoch in astronomical history. Astronomy had appar­ the rise of a school of exact science, cosmology and fected by the new system. While the Scholastics were ently settled down in fairly conventional lines. One cosmogony parted company. Hipparchus and his suc­ still vainly trying to refute Copernican ism, and the of the beneficial results of Newton's great work in cessors did not concern themselves with the origin of theologians were engaged in hurling anathemas at the science was the concentration of the minds of astrono­ things, and so the idea of evolution or development heads of its supporters, the new system of the world mers on the great task of the verification of the law of which had made its appearance in the guesses of the was being established on a firm theoretical basis. gravitation. Astronomical observation had for its end Ionian philosophers was almost forgotten. After the and aim the confirmation and perfection of the New­ conversion of the Roman world to Christianity, the THE NEWTONIAN SYSTEM. tonian theory, and so attention was directed chiefly to Hebrew cosmogony contained in the first chapter of Tycho Brahe was no great constructive thinker; he the bodies of the solar system, their motions and Genesis was accepted throughout Christendom as the contributed little to the actual cosmological conception lllutual perturbations. The stars were observed prin­ final word in the method of creation. The theory of of the time,-for while he abandoned the ptolemaic dpally as convenient reference-points by which the po­ six literal days of Creation and a "carpenter God" theory, he could not adopt the Copernican, and found sitions of the moon and planets could be accurately was accepted without question for hundreds of years. refuge in a half-way house known to posterity as the lixed. In the course of these observations, several Curiously enough, it was a theologian, Ralph Cud­ Tychonic system, which, while conceding the motion facts, it is true, were ascertained. Thus in 1718 Halley worth, who in 1678, in his "Intellectual System of the of the other planets round the sun, preserved the immo­ noticed that the stars Sirius, Aldebaran, Betelgeuse, Universe," argued against the prevalent mechanical bility of our world. But Tycho was one of the most and Arcturus had perceptibly moved since the forma­ theory of a literal and finished creation, and in favor of industrious collectors of data whom this world has ever tion of the ptolmaic catalogue. Efforts too were made development in accordance with an immanent principle. seen, and from the data collected by him the new sys­ to measure the distances of the brighter stars. In ad­ In the eighteenth century our illustrious Scottish as­ tem of the world was to lie finally confirmed. After his dition, isolated thinkers, Kant and Lambert in Ger­ tronomer, James Ferguson, threw out a remarkable exile from Denmark, he became acquainted with Kepler, many, and Wright and Michell in England, speculated hint as to the building-up of the solar system as a re­ who came into possession of Tycho's huge mass of ob­ on the structure of the sidereal universe, and some sult of gravitational action. "In the beginning," he servations when the latter died. By means of these,­ marvellous intuitions were reached. But there were no said, "God brought all the particles of matter into be­ the most perfect hitherto made,-Kepler sought to dis­ data on which to haRt' a theory of the cosmos external ing in those parts of open space where the sun and cover (1) how the planets revolved round the sun, and to our solar system. planets were to be formed, and endowed each particle (2) why they revolve. He was successful in his first This was the state of affairs when William Herschel with an attractive power, by which these neighboring quest, and the three empirical "laws" of planetary mo­ appeared on the scene. He was not a great mathema­ and at first detached particles would in time come to­ tion are the monument of his labors. He failed in his tician, and his work lay in the direction of making ob­ gether in their respective parts of space, and would second quest. The force controlling the planetary mo­ servations and systematizing the results which he de­ form the different bodies of the solar system." tions he believed to have its origin in the sun. But rived from them. The nebular hypothesis, as we know it, originated he was unable to reach any definite conclusion, and it Herschel's contributions to cosmological thought may independently in the minds of three men,-Kant, La­ was reserved for Newton to enunciate the law of be summed up under these heads: (1) He demonstrated, place, and Herschel. Neither Laplace nor Herschel gravitation, which made intelligible the empirical laws what other observers and writers had believed to be seems to have been acquainted with Kant's speculation of Kepler. The importance of Newton's great work probable, the essential kinship of the sun with the stars. or with the views of each other. Kant and Laplace cannot be overrated. Laplace declared that the "Prin­ In his bold and masterly paper contributed to the proceeded on the deductive method. Their theories cipia has a pre-eminence over all productions of the Royal Society of London in 1783, Herschel, making llse were pure speculations. Herschel was led by his ob­ human intellect." of the proper motions of seven stars and separating servations of nebulre and nebulous stars to postulate The Newtonian theory not only profoundly influ­ what he believed to be their real from their apparent the gradual development of nebulre into stars and plan­ enced astronomy and shaped its whole future course; motions, reached the conclusion that the sun, carrying ets. Laplace had declared that at one time the solar it profoundly affected all human thought. In the first with it the planets and satellites, was moving towards system had been in a nebulous or gaseous state. Her­ place, Newton demonstrated the simplicity and unity a point in the heavens near to the star Lambda Her­ schel pointed out that such gaseous masses were actu­ of the known universe. The old idea of a radical culls. Copernicus had shown that the earth, so far ally in existence in the heavens, in all stages of evo­ difference between things celestial and things terres­ from being the center of the universe, was but one lution. trial,-already seriously damaged by the observations planet among others in ceaseless revolution round the At first the nebular theory was received with indif­ of Tycho Brahe and Galileo,-was now definitely re­ sun. Herschel now proved that the sun itself was not ference. Laplace had promulgated his view, diffidently, futed. The whole planetary system was seen to be the central body, but was merely one star among in the appendix of a popular book. Herschel published ruled by one law. In the second place, as Hoffding others in ceaseless motion through the depths of space. no books, and his gradually developing views were only has truly remarked, "It was now clear that the fixed (2) Herschel's investigations of double stars led him to be understood by a study of his papers in the "Philo­ and law-abiding order of Nature prevails not only here to the conclusion that the law of gravitation held sway sophical Transactions" of the Royal Society. Gradually on this Earth but also throughout the Universe." The throughout the depths of space. Newton had shown the indifference died away. Theological writers and world was now seen to be a huge machine. The scien­ that the law ruled in the solar system, and his succes­ scholars opposed the theory bitterly, but there was also tific doctrine of the uniformity of nature, of which so sors demonstrated that that law explained nearly all a scientific opposition, for the average scientist of the much has been heard in philosophy and scientific the irregularities of the planetary motions. From time was still at the stage of the mechanical conception thought, was now definitely established. In the third analogy it might have been supposed that the same of nature. place, the era of the machanical conception had dawned: law ruled the system of the stars, but there was no Slowly but surely the mechanical theory was passing and this mechanical conception had an abiding influ­ proof. When Herschel demonstrated that several double away. Even in theology Deism was giving place to ence over human thought. Hoffding has pointed out the stars were in revolution round their common centre of the new sense, which we find in Coleridge and Schleier­ remarkable connection between Newton's religious con­ gravity, he supplied the proof. macher, of the Divine immanence; in philosophy the ceptions and his doctrine of mathematical physics,-a (3) Herschel's long-continued series of studies on the empiricism of the French school was giving way before connection which arose through his concept of space construction of the heavens did not result, it is true, the idealism of Fichte, Schelling, Hegel, and Goethe; as the organ by means of which God works as omnipo­ in the solution of that problem. and in physics the whole mechanical concept of empty tent in the world. The famous disc-theory was put forwarll only to be space and isolated bodies was disappearing. In 1801 Newton proceeds to prove, from the purpose and or­ abandoned, and when Herschel died, he left the prob­ 'l'homas Young revived the wave theory of light, which der in the world, the existence of God. The world is lem further from solution than ever. But his researches assumed the existence of a luminiferous ether. Each a great machine, set in motion by God, Who by super­ did prove that the sidereal heavens constituted a of these developments had its effect upon human natural means has arranged the masses, distances and greater system, of which the solar system formed part. thought. The contribution of astronomy was the work velocities of the planets; but the interference of God And Herschel's researches demonstrated also the vast ()f Herschel and Laplace in showing the possibility that is required from time to time, owing to the irregulari­ scale on which the universe was built. His theory thaf the celestial bodies had arrived at their present condi­ ties arising from the actions of the varous bodies on star-clusters and nebulre formed universes external to tion in obedience fo a process of evolution. Thus, as­ one another,-an idea which drew from Leibnitz the our Galaxy implied an immense extension of the uni­ tronomical science, no less than geological, enormously criticism that Newton had compared the universe to a verse in space and time. In conversation with the poet extended the period during which the universe had been clock, which required the constant interference of the Campbell in extreme old age, Herschel said truly, "I known to exist. watchmaker. have looked further into space than ever human be­ Herschel's discovery of the solar motion had shown Deism in the religious sphere conceived of God as ex­ ing did before me," adding more hypothetically, "I the sun to be in every respect similar to the other stars. ternal to His works; and the Newtonian cosmology in have observed stars, of which the light, it can be His investigations of the construction of the heavens the hands of Newton, and more particularly of his dis­ proved, must take two millions of years to reach this had shown that the stars actually formed a connected tinguished successors and the popularizers of his sys­ earth." The stupendous vistas opened up by Herschel's system. The new theory of light, by destroying the tem, inevitably regarded the Creator in a similar light. work had an enormous influence on contemporary conception of empty space, assumed the unity of the Men such as Ferguson, and even Paley himself, never thought. As Horace Walpole expressed it,-"One's (Oontinued on page 352)

© 1919 SCIENTIFIC AMERICAN, INC. 352 SCIENTIF]CAMERICAN SUPPLEMENTNn 2265 May 31,1919

larly affecting the evenness of the lighting, provided its consequences are so helpful as to suggest a distinct Herschel enormously extended the universe both in the slide or negative is sufficiently dense, which goes to probablllty of its truth." space and time. Not only did his telescopes reveal prove the soundness of the conclusions here suggested. (1) On the whole, the theory agrees with the theory stars sunk in the very depths of space; by his wonderful -A. LOCKETT, in Brit. Jour. Photog. of the universe, now widely held, that our stellar sys­ intuition he grasped the great truth of evolution as the tem is a spiral nebula. "The two arms of the spiral," explanation of celestial phenomena, and so, from the says Eddington, "have an interesting meaning for us mechanistic conception of the universe, astronomers The Influence of Astronomy on Human Thought in connection with stellar movements." The universe were gradually led to view the universe as an organ­ (Continued from page 343) appears, according to present-day astronomers, to con­ ism, developing from within. (5) Finally, the work of universe. But this unity was first actually proved by sist of two great star-streams moving in different di­ Herschel and of the nineteenth-century astronomers the marvelous revelations of spectrum analysis. rections. On the spiral nebula theory the prevalence have shown the universe to be a unity. The work of Fraunhofer, cut short by his early death, of motions in opposite straight lines is explained. To the higher thought the chief contribution of mod­ was carried forward by Kirchoff, with the resuft that (2) As already mentioned, the spiral nebula! shun ern astronomy undoubtedly is this sense of infinity of 1859 in the spectroscope became the adjunct of the the zone of the Milky Way altogether. According to epace and eternity of time. And theology, which fought telescope. In 1823 Comte had declared that one thing the island universe theory, this is explained. In that for so long against Copernicus, Newton, and Her­ at least man could never know,-the chemical compo­ region the external universes are blotted out from view, schel realizes now that it has reason to revere the mem­ sition of the celestial bodies. In less than forty years not only by the star-clouds of the galaxy, but by vast ory of the astronomers who first unveiled the great the seemingly impossible had been accomplished. As a tracts of absorbing matter. truths of the immutability of natural law, the unity result the chemical unity of the universe was found to At present, we can only say that the balance of evi­ of the universe, and its subjection to one great law of bE' a truth of nature. The cosmos was seen to be in dence is in favor of the view that, not only is our nature, the infinity of space and the eternity of time, very truth a cosmos, connected and inter-related in all stellar system limited, but that we can see beyond its for in the contemplation of these great themes, science, its parts. confines to other similar systems at distances so vast philosophy, and theology find their meeting-place. The history of astronomical science in the last half that the mind is unable to comprehend them, so vast centulry has been the record of the triumph of telescope, rhat light will require tens and hundreds of thousands, spectroscope, and camera; as a result of the ceaseless if not milllons, of years on the journey. And we must labor of astronomers, several facts are tolerably certain retnember that this collection of island universes, in­ SCIENTIFICAMERICAN today. cludink our own, will in all likelihOOd form another and SUPPLEMENT What is the form and extent of the universe'! The greater system of a higher order. Truly, as Richter Founded 1876 problem is a very old one, and our conception today is says, "the spirit of man acheth with this infinity." not so definite as that of Herschel when he formulated Thus, the astronomical view of the entire universe Published by Scientific American Publishing Co. his famouos disc-theory of the stellar heavens. teaches us that it is a unity-one great system bound New York, Saturday, May 31,1919 In the first place, that collection of stars known together by the law of gravitation-in continuous pro­ MUDD & Co., 233 Broadway, New York variously as the Stellar Universe, the Sidereal Sys­ gressive development. The difference between the Charles Allen Munn, President; Orson D. Munn, Treasurer tem, and the Galaxy, although of vast dimensions, seems world-concept of today and that of the Middle Ages Allan C. Hoffman. Secretary, all at 233 Broadway to be limited in extent. That ..the universe of stars is may be best realized by a comparison of the view of finite in extent may be proved by a calculation original­ our earth's position then held with the view current The Scientific American Publications ly mentioned by the German astronomer Olbers, which today. The medieval cosmology placed the earth in the Scle"1ific American Supplement (established 1876) per year $5. 00 was used with great force by Newcomb and Gore in center of the universe; it was not only relatively but Scientific American (established 1845) . 5.00 The combined subscription rates and rates to foreign countries their investigation of the extent of the stellar system. absolutely the most important part of creation. Sun, Including Canada, will be furnished upon application. There are three times as many stars of any given mag­ moon, and stars were created 6,000 years ago on the Remit by postal or"express money order. bank draft or check. nitude as of the magnitude immediately brighter. Thus, fourth day of Creation, for the sole purpose of giving Scientific American Publishing Co. the increase of number more than compensates for the light to the earth's inhabitants. Today, our view of 233 Broadway, New York decrease of brightness, and were the stars infinite in our world's place is vastly different. So far from being number, the whole heavens would shine with greater the center of the universe, the earth is merely one of The purpose of the Supplement is to publish the brilliance than the sun. It has also been shown con­ the planets revolving round the sun, and by no means more important announcements of distinguished clusively that in certain portions of the sky observers the largest. The sun itself- relatively vast though it technologists, to digest significant articles that appear have penetrated to the limits of the universe. In these is- is by no means the chief body of the cosmos; it is in European publications, and altogether to reflect parts large telescopes do not show more stars than merely a rather subordinate star-one of five hundred the most advanced thought in science and industry smaller instruments, proving conclusively that, in these million or more, merely one shining speck in the jew­ throughout the world. regions at all events, the universe is finite. It is true elled casket of heaven. Flammarion, in two short pas­ that the universe is very vast in extent. The photo­ sages, brings out very clearly and impressively the ut­ Back Numbers of the Scientific American graphs of Professor Max Wolf and Professor Barnard terly insignificant place which our world actually oc­ Supplement have revealed untold numbers of stars; nevertheless, cupies in the scheme of things. Speaking of the celes­ SUPPLEMENTS bearing a date earlier than January the starry system seems to be strictly limited. tial motions, he says,-" Such are the stupendous mo­ 1st, 1918, can be supplied by the H. W. Wilson Com­ What of the extent of our utliverse? Various esti­ tions which carry every sun, every system, every world, pany, 958-964 University Ave., Bronx, New York, N. Y. mates have been made, and they differ considerably. all life, and all destiny in all directions of the infinite Please order such back numbers from the Wilson Com­ These distances are generally measured, not in miles immensity, through the boundless, bottomless abyss; pany. Supplements for January 1st, 1918, and subse­ but in "light-years"-the number of years which light, in a void forever open, ever yawning, ever black and quent issues can be supplied at 10 cents each by travelling at the rate of 186,000 miles a seconn, re­ ever unfathomable; during an eternity, without days, S CIENTIFIC AMERICAN PUBLISHING Co., 233 Broadway, quires to travel from the stars to the earth. Seeliger without years, without centuries or measures. Such is New York. of Munich has calculated that the limits of the uni­ the aspect, grand, splendid, and SUblime of the universe, verse are about 9,000 light-years from the solar sys­ which flies through space before the dazzled and stupe­ WE wish to call attention to the fact that we are in a fied gaze of the terrestrial astronomer, born today to tem-which is, roughly speaking, in the central region position to render competent services in every branch of the universe. Newcomb reached a smaller estimate die tomorrow, on a globule lost in tfie infinite night. of patent or trade-mark work. Our staff is composed -3,000 light-years. More recen tly, in 1911, after an "Our science is but a shadow on the face of the re­ of mechanical, electrical and chemical experts, thor­ elaborate investigation, See reached the conclusion that ali ty. Infinity encompasses us, on all sides life asserts oughly trained to prepare and prosecute all patent ap­ "the most remote stars are separated from us by a itself, universal and external; our existence is but a plications, irrespective of the complex nature of the distance of at least ],000,000 light-years." There is, fleeting moment, the vibration of an atom in a ray of subject matter involved, or of the specialized, technical, therefore little or no unanimity as to the actual extent the sun, and our planet is but an island floating in the or scientific knowledge required therefor. of the sidereal system. It is very vast, though finite, celestial archipelago to which no thought will ever We also have associates throughout the world, who and probably only one of a number of similar systems. place any bounds. Never lose Sight of the fact that assist in the prosecution of patent and trade-mark ap­ Have we any positive knowledge of such systems? space is infinite, that there is in the void neither height plications filed in all countries foreign to the United 'l'owards the close of the eighteenth century, the view nor depth, neither right nor left, and in time neither States. that star-clusters and nebula> were "island universes," begnning nor end. We must understand that our con­ MUNN & Co., analogous to our Milky Way, enjoyed considerable pop­ ceptions are relative to our imperfect and transitory Branch Office: Patent Solicitor" ularity. In the nineteenth century, it fell into disfavor, impreSSions, and that the only reality is the Absolute." 625 F Street, N. W., 233 Broadway, and was very generally abandoned after the spectro­ CONCLUSION. Washington, D. C. New York, N. Y. scopiC discovery of the gaseous nature of many nebula!. As a sweeping generaliza tion, its abandonment was It (1) The old geocentric theory of the world had its neceSSity, for the irregular nebula! are not star-clusters, basis in the ancient astronomy. (2) The revolution Table of Contents PAGE hut masses of gas, and the star-clusters proper show a in astronomy associated with the name of Copernicus Colloidal Fuels ...... 338 tl'lldency to cluster on the Milky Way. swept away the old conception of a central earth, and Concrete as 4{' Chemic';l Engineering Material-By Max But all nebula! so-called do not show gaseous spectra. exerted a powerful influence on theology and philosophy Toch ...... 339 Acid-resisting Iron ...... 340 A numerous class-the famous spiral nebulffi-have as well as on science. (3) While all branches of Infiuence of Aviation on Mathematical Physics...... 341 spectra which, despite individual peculiarities, may be human thought influence one another, it may be safely The Sizes of Cells...... 341 described as continuous. The view is gradually gain­ said that the epoch-making work of Newton exerted Artificial Gravel ...... 341 ing ground that these so-called spiral nebula! are ex­ the greatest influence on intellectual activity in the sev­ Infiuence of Astronomy on Human Thought-By Rev. ternal universes, analagous to our Milky Way. Pro­ enteeth century. The conception of natural law and Hector Macpherson ...... 342 Some Native Industries of German Camel'oon...... 344 fessor Eddington of Cambridge, who has made the causality with which we of today are familiar has its Philosophy and S.piritualism...... 345 problem of the construction of the universe peculiarly origin in Newton's great law of gravitation, which has Physical Relativity-By G. W. de Tunzelman ...... 346 his own, inclines towards the view. Spiral nebula! are remained to this day the foundation of all scientific Determination of the Compressibility of Solids at High difficult to account for on any other hypothesis. Not work. Newton, as we have seen, profoundly influenced Pressures . . _ ...... 347 only are they differentiated from other nebula! by their the whole course of astronomy. Not only so; the New­ The Shell Builders-H.-By W. R. Shufeldt...... 34 8 Cutting Lubricants ...... 350 continuous spectra; they do not obey the law of galactic tonian concept of the solar system as a great machine Covering Power and ',Illuminating Power of Lenses: Tests " concentration, and betray no affinities with early ....,ype had something to do with the rise and popularity of the and Performance---By C. Welborne Pi per ...... 351 stars. "The island universe theory," says Eddington, Deistic movement in theology. (4) The work of Her­ Position of the Illuminant in Enlarging and Projection- "is much to be preferred as a working hypothesis; and schel had an influence only second to that of Newton. By A. Lockett...... 351

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