From the collection of the 
 
 
 PreTinger 
 
 i a 
 
 JJibrary 
 
 San Francisco, California 
 2006 
 
DISCOVERY 
 
MACMILLAN AND CO., LIMITED 
 
 LONDON BOMBAY CALCUTTA 
 MELBOURNE 
 
 THE MACMILLAN COMPANY 
 
 NEW YORK BOSTON CHICAGO 
 DALLAS SAN FRANCISCO 
 
 THE MACMILLAN CO. OF CANADA, LTD. 
 
 TORONTO 
 
Cofc\'n\i>lit. Edit-in Austin Ahlx'Y. t'i>/>_v/,ij///, Cintis & L'niucron. 
 
 I. WISDOM, OR THE SPIRIT OF SCIENCE. 
 Mural painting by Edwin Austin Abbey, R.A., (1852-1911), in 
 the Harrisburg Capitol, Pennsylvania. The inscription reads: 
 "I am what is, what shall be, what hath been. My veil hath been 
 disclosed by none. The fruit which I have brought forth is this- 
 the sun is born." 
 

DISCOVERY 
 
 Or T/ie Spirit and Service of Science 
 
 BY 
 
 R. A. GREGORY 
 
 MACMILLAN AND CO., LIMITED 
 
 ST. MARTIN'S STREET, LONDON 
 
 1916 
 
\:WPY&IGHT. 
 
 GLASGOW: PRINTED AT THE UNIVERSITY PRESS 
 BY ROBERT MACLEHOSE AND CO. LTD. 
 
PREFACE 
 
 THE attention recently given to the position of science 
 in the State, its relation to industry, and its relative 
 neglect in education, suggests that the present is an 
 appropriate time for putting into final shape a project 
 contemplated for many years and practically completed 
 before the outbreak of existing hostilities. This book 
 represents the result ; and its main purposes are to 
 promote a more sympathetic attitude towards those who 
 are engaged in the pursuit of scientific truth and to 
 remove the widespread misconception which prevails as 
 to the meaning and influence of science. 
 
 To the popular mind, a man of science is a callous 
 necromancer who has cut himself off from communion 
 with his fellows, and has thereby lost the throbbing 
 and compassionate heart of a full life : he is a Faust 
 who has not yet made a bargain with Mephistopheles, 
 and is therefore without human interest. Scientific and 
 humanistic studies are, indeed, supposed to be anti- 
 pathetic, and to represent opposing qualities ; so that 
 it has become common to associate science with all that 
 is cold and mechanistic in our being, and to believe 
 that the development of the more spiritual parts of 
 man's nature belongs essentially to other departments 
 of intellectual activity. 
 
 When scientific work is instituted solely with the 
 object of securing commercial gain, its correlative is 
 
 341213 
 
vi PREFACE 
 
 selfishness ; when it is confined to the path of narrow 
 specialisation, it leads to arrogance ; and when its pur- 
 pose is materialistic domination, without regard for the 
 spiritual needs of humanity, it is a social danger and may 
 become an excuse for learned barbarity. But scientific 
 research is rarely inspired by these motives, and devotion 
 to it does not necessarily inhibit response to other notes 
 with which a well-balanced mind should be in symphony. 
 Moreover, direct contact with Nature and inquiry into 
 her laws produce a habit of mind which cannot be 
 acquired in literary fields, and they are associated with 
 a wide outlook on life more often than is usually 
 supposed. 
 
 The relative influence of different studies on the for- 
 mation of character need not be discussed here ; yet 
 the following pages will perhaps show that the spirit 
 of scientific research has inspired the highest ethical 
 thought and action, as well as increased the comforts of 
 life, and added greatly to material welfare. We seek to 
 justify the claim of science to be an ennobling influence 
 as well as a creator of riches ; and therefore as much 
 importance is attached to motive and method as to 
 discovery and industrial development, however marvel- 
 lous or valuable these may be. 
 
 Wherever purposeful inquiry is carried on in the 
 field of Nature, there the spirit of science is manifest, 
 and we learn that worthy intention defines its shape 
 as much as brilliant achievement. For science is 
 not to be measured by practical service alone, though 
 it may contribute to material prosperity : it is an 
 intellectual outlook, a standard of truth and a gospel 
 of light. 
 
 Scientific investigation is not usually undertaken 
 with personal profit in view, and the discoveries to 
 
PREFACE vii 
 
 which it leads are not jealously kept within the precincts 
 of the temple, but are offered freely to the world : self- 
 help thus giving place to the higher attribute of help 
 for others. This virtue, with the qualities of self- 
 sacrifice, persistence, courage, duty, accuracy, humility, 
 and hope may all be abundantly exemplified from the 
 careers of men of science ; yet such instances are rarely 
 mentioned. From many countries and many times we 
 have gathered incidents and allusions which display the 
 nobility of scientific aims, and have accentuated them 
 with words of wisdom from the biographies and writings 
 of men who have devoted their lives to the extension of 
 natural knowledge. In substance the book thus largely 
 consists of selected testimony, while in intention it is a 
 stimulus to high endeavour. 
 
 No attempt has been made to provide a complete 
 record, in chronological or any other order, of natural 
 philosophers and their triumphs, yet it is hoped that 
 not many points of outstanding human interest have 
 been overlooked. The aim has been eclectic rather 
 than exhaustive ; wherefore many scientific pioneers 
 are not mentioned, while others find a place not so much 
 on account of their distinguished eminence as because 
 events in their careers, or results of their work, create 
 a spirit of emulation in those who regard them. The 
 whole is presented with a deep sense of humility before 
 the extent and intricacy of scientific knowledge, and of 
 dissatisfaction at the gap which persists between design 
 and execution. 
 
 It remains only to be said that though none of the 
 chapters have been published hitherto in their present 
 form, a few parts have appeared in contributions to the 
 Cornhitt, Fortnightly, Nature, School World, Sunday al 
 Home, and other magazines during a period extending 
 
viii PREFACE 
 
 over nearly a quarter of a century. The book as a whole 
 owes little to these articles ; nevertheless, grateful 
 acknowledgment is offered for the further use now 
 made of suitable material extracted from them. 
 
 K. A. GREGORY. 
 
CONTENTS 
 
 CHAPTKB PAGE 
 
 I. OUTLOOK AND ENDEAVOUR 1 
 
 II. TRUTH AND TESTIMONY 23 
 
 III. THE SCIENTIFIC MIND ----- 36 
 
 IV. PURSUIT OF KNOWLEDGE 56 
 
 V. BELIEF AND EVIDENCE 92 
 
 VI. INQUIRY AND INTERPRETATION - - - - 125 
 
 VII. LAW AND PRINCIPLE ----- 165 
 
 VIII. CONQUEST OF DISEASE 201 
 
 IX. SCIENTIFIC MOTIVE - 234 
 
 X. PRACTICAL PURPOSE 256 
 
 XI. ACROSS THE BORDER ------ 292 
 
 XII. TOWARDS INFINITY - - 311 
 
 BIOGRAPHICAL INDEX 330 
 
ILLUSTRATIONS 
 
 PLATES FACING PAGE 
 
 I. WISDOM, OR THE SPIRIT OF SCIENCE. BY EDWIN 
 
 AUSTIN ABBEY Frontispiece 
 
 II. THE SPIRIT OF THE SUMMIT. BY LORD LEIGHTON 48 
 
 III. SCIENCE. BY KENYON Cox- - - - 112 
 
 IV. URANIA THE MUSE OF ASTRONOMY. BY E. 
 
 EARLOM, AFTER G. B. CIPRIANI - - 144 
 
 V. THE THINKER. BY AUGUSTE KODIN - - 192 
 
 VI. SCIENCE. BY GIOVANNI DA BOLOGNA - - - 224 
 
 VII. SCIENCE REVEALING THE TREASURES OF THE EARTH. 
 
 BY EDWIN AUSTIN ABBEY - 256 
 
 VIII. APOTHEOSIS OF THE SCIENCES. BY PAUL ALBERT 
 
 BESNARD 320 
 
CHAPTER I 
 OUTLOOK AND ENDEAVOUR 
 
 No good work is ever lost. Max-Miiller. 
 
 There is no darkness but Ignorance. Shakespeare. 
 
 All wish to know, but few the price will pay. Juvenal. 
 
 AH science has one aim, namely, to find a theory of 
 Nature. R. W. Emerson. 
 
 Tongues in trees, books in the running brooks. Sermons 
 in stones, and good in everything. Shakespeare. 
 
 Nature alone is always true to herself ; she alone through 
 the ages never lies, never changes, never hesitates, ever 
 presses onwards. Eden Phillpotts. 
 
 There are three voices of Nature. She joins hands with us 
 and says Struggle, Endeavour. She comes close to us, 
 we can hear her heart beating, she says Wonder, Enjoy, 
 Revere. She whispers secrets to us, we cannot always 
 catch her words, she says Search, Inquire. These, then, 
 are the three voices of Nature, appealing to Hand, and 
 Heart, and Head, to the Trinity of our Being. Prof. 
 J. Arthur Thomson. 
 
 SINCE dawn the man had been seated on a stone at the 
 bottom of a ravine. Three peasant women on their 
 way to the vineyards exchanged " Good day " with him 
 as they passed to their work. At sunset when they 
 returned the watcher was still there, seated on the same 
 stone, his eyes fixed on the same spot. " A poor 
 innocent," one whispered to the others, " pe'ca'ire ! a 
 poor innocent," and all three made the sign of the cross. 
 
 G.D. A <E 
 
? :I>feCOVERY CH. 
 
 Fabre, the incomparable naturalist, patiently waiting 
 to discover what is instinct and what is reason in insect- 
 life is, to these vintagers, an object of supreme com- 
 miseration, an imbecile in God's keeping, wherefore they 
 crossed themselves. 
 
 Members of the University of Pisa, and other onlookers, 
 are assembled in the space at the foot of the wonderful 
 leaning tower of white marble in that city one morning 
 in the year 1591. A young professor climbs the spiral 
 staircase until he reaches the gallery surmounting the 
 seventh tier of arches. The people below watch him as 
 he balances two balls on the edge of the gallery, one 
 weighing a hundred times more than the other. The 
 balls are released at the same instant and are seen to 
 keep together as they fall through the air until they are 
 heard to strike the ground at the same moment. Nature 
 has spoken with no uncertain sound, and has given an 
 immediate answer to a question debated for two thousand 
 years. 
 
 " This meddlesome man Galileo must be suppressed," 
 murmured the University fathers as they left the square. 
 " Does he think that by showing us that a heavy and 
 a light ball fall to the ground together he can shake 
 our belief in the philosophy which teaches that a ball 
 weighing one hundred pounds would fall one hundred 
 times faster than one weighing a single pound ? Such 
 disregard of authority is dangerous, and we will see 
 that it goes no further." So they returned to their 
 books to explain away the evidence of their senses ; 
 and they hated the man who had disturbed their philo- 
 sophic serenity. For putting belief to the test of experi- 
 ment, and founding conclusions upon observation, 
 Galileo's reward in his old age was imprisonment by 
 the Inquisition, and a broken heart. That is how a 
 
i OUTLOOK AND ENDEAVOUR 3 
 
 new scientific method is regarded by guardians of 
 traditional doctrine. 
 
 The most original experimenter the world has ever 
 seen is lecturing before a distinguished audience at the 
 Royal Institution in London. He shows that when a 
 magnet is brought suddenly near a coil of wire a slight 
 current of electricity is produced in the wire. The 
 experiment is not very impressive ; and a lady probably 
 voiced the feelings of most of the audience when she 
 asked afterwards, " But, Professor Faraday, even if the 
 effect you explained is obtained, what is the use of it ? " 
 The memorable reply was, " Madam, will you tell me 
 the use of a new-born child ? " 
 
 Lecky, in the Introduction to his Democracy and 
 Liberty, says that the whole great field of modern 
 scientific discovery seemed out of the range of even such 
 a scholar and statesman as Mr. Gladstone, and that 
 when Faraday was endeavouring to explain to Gladstone 
 and several others an important new discovery in science, 
 Gladstone's only commentary was, " But, after all, 
 what use is it ? " "Why, sir," replied Faraday, " there is 
 every probability that you will soon be able to tax it ! " 
 
 To cultured people, Faraday's discovery of a means 
 of producing electricity by mechanical movement seemed 
 trivial ; to the schoolmen of the Middle Ages, Galileo's 
 appeal to the court of Nature against the judgment of 
 authority was impertinent ; and to the peasant, Fabre's 
 patient study of insects suggested imbecility. 
 
 Three typical scientific workers are here represented ; 
 and we see the attitude of three different classes of 
 people towards them. There is first of all the naturalist 
 who seeks knowledge purely for its own sake, and con- 
 siders no vigil too long if at the end a corner of the veil 
 behind which the mysteries of Nature are hidden has 
 
4 DISCOVERY CH. 
 
 been lifted. He continually sees new beauties in the 
 features of his mistress and new wonders in all her ways. 
 Sufficient for him is the satisfaction he feels at each 
 discovery, and he cares not whether his studies have 
 any value beyond that which he derives from them. 
 In a world of hustle, such lovers of Nature are regarded 
 as creatures to be pitied, if not held up to ridicule, by 
 people who cannot understand why anyone should 
 devote himself to a subject without expecting personal 
 or public profit from it. 
 
 Of a different type is the iconoclast the breaker of 
 images rebelling against authority, impetuous to prove 
 that the old idols are false, impatient with the world 
 because of its indifference to the new gospel he has to 
 teach. This man is not content to see things for him- 
 self ; he desires to convince others of the truth revealed 
 to him, and single-handed he is prepared to storm the 
 citadel of traditional belief. In all ages he is a disturber 
 of the peace, and is as unwelcome in scientific circles 
 to-day as he was to the contemplative philosophers of 
 the Middle Ages or before. But be assured of this : 
 you may crucify the body of such an apostle or you may 
 visit him with the despair that follows upon neglect, 
 but if his torch has been lighted from the divine flame 
 of truth and righteousness it cannot be extinguished. 
 
 Most men of science are neither suppliants at the feet 
 of Nature nor fiery advocates of truths wrested from her, 
 but by critical inquiry into the origin of her strength 
 and weakness they hope to discover the means of sub- 
 duing her. She is cross-examined, tested, analysed, and 
 every artifice or weapon which seems likely to induce 
 her to reveal the secrets which she holds is brought into 
 requisition. She is a Katharine to be tamed by the 
 Petruchio of Science rather than a Juliet to be wor- 
 
i OUTLOOK AND ENDEAVOUR 5 
 
 shipped by a love-sick Romeo. Only those who consider 
 her worthy of battle have the patience or the power to 
 effect a conquest. From whatever side she is approached 
 obstacles arise which prevent a clear vision of her ; and 
 infinite labour as well as strong desire are necessary 
 for every step of advance. 
 
 Pasteur carried on an unrelenting warfare against the 
 forces of Nature hostile to man ; it took him five years 
 to discover the remedy for rabies. Above all, he was an 
 indefatigable worker. He called the interval of night 
 " hours of waiting," which always seemed to him slow 
 to pass. C. G. J. Jacobi (1804-1851), the greatest 
 mathematical teacher of his generation, likewise made 
 the best use of time. " It must not be supposed," he 
 said, " that it is to a gift of Nature that I owe such 
 mathematical power as I possess. No, it has come by 
 hard work, hard work. Not mere industry, but brain- 
 splitting thinking hard work ; hard work that has 
 often endangered my health." 
 
 Several years ago the leading astronomers in the 
 United States were asked to set down in order of prefer- 
 ence the names of living Americans who had contributed 
 most to the progress of astronomy. The name which 
 headed all the lists was that of Simon Newcomb, yet 
 he made no discovery in astronomy to which the period- 
 ical press would give prominence. Far greater, however, 
 than the observation of a new star, planet, or comet, 
 was the exceedingly laborious computations made and 
 directed by Newcomb to enable the positions of the sun,* 
 moon, planets and some of the fixed stars to be pre- 
 dicted with greater accuracy than had hitherto been the 
 case. This was the work which gave him the first place 
 in the esteem of men who were best able to judge its 
 value to astronomical science. 
 
6 DISCOVERY CH. 
 
 When the French astronomer and mathematician, 
 Lalande, was computing with Clairaut the disturbing 
 influences to which Halley's comet had been subjected, 
 he worked at the calculations during six months from 
 morning to night, and often at meal times ; and by his 
 devotion to this self-imposed task, contracted an illness 
 which changed his constitution for the rest of his life. 
 It was necessary to calculate the distance of each of the 
 two planets Jupiter and Saturn from the comet separately 
 for every degree over a period of one hundred and fifty 
 years. There was no mercenary motive under this 
 tremendous labour, but only the desire to define the 
 movements of an object which at intervals of about 
 seventy-six years had filled mankind with terror by its 
 appearance in the sky. 
 
 Reward as the world understands it for work done 
 or results obtained, is the last thought of a student of 
 science. " I have no time to make money," was the 
 reply of the naturalist, Louis Agassiz, to an offer to lend 
 himself to a legitimate and tempting financial scheme. 
 Napoleon the Third once expressed surprise to Pasteur 
 that the great investigator did not endeavour to make 
 his discoveries and their applications a source of profit. 
 " In science," Pasteur replied, " men of science would 
 consider that they lowered themselves by doing so." 
 In a conversation with Lady Priestley, Pasteur 
 remarked, " I could never work for money, but I would 
 always work for science." If he had chosen to keep 
 his discoveries to himself, he could have been one of the 
 most wealthy men in the world, but he gave them to the 
 human race, and was content to end his career as a 
 professor of chemistry in receipt of a modest salary 
 from the Government of his country. 
 
 Faraday on one occasion said to Tyndall that, at a 
 
i OUTLOOK AND ENDEAVOUR 7 
 
 certain stage of his career, he was forced definitely to 
 ask himself, and finally to decide whether he would 
 make wealth or science the pursuit of his life. He could 
 not serve two masters, and he chose science. After the 
 discovery of magneto-electricity, his fame was so well 
 recognised that the commercial world would not have 
 considered any fees too high for the aid of abilities like 
 his. Tyndall says he might with ease have realised an 
 income of 10,000 a year during the last thirty years of his 
 life, yet he earned almost nothing by professional services. 
 
 Taking the duration of his life into account, this son of a black- 
 smith, and apprentice to a bookbinder, had to decide between a 
 fortune of 150,000 on one side, and his undowered science on 
 the other. He chose the latter and died a poor man. But his 
 was the glory of holding aloft among the nations the scientific 
 name of England for a period of forty years. Tyndall. 
 
 The invention of the miner's safety-lamp by Sir 
 Humphry Davy was based upon scientific researches 
 described by him to the Royal Society between 1815 
 and 1817. The investigations were undertaken at the 
 request of a " Society for Preventing Accidents in 
 Mines/' formed in 1813 in consequence of the increase 
 of colliery explosions as pits of greater depth were worked. 
 The Society looked to scientific men to provide " a 
 cheap and effectual " remedy for these calamities, and 
 Davy's assistance was secured in 1815, after a number 
 of impracticable suggestions had been considered. 
 
 As the result of experiments, Davy discovered the 
 principle upon which safety-lamps are constructed, 
 namely, " that explosive mixtures of mine-damp will 
 not pass through small apertures or tubes ; and that if 
 a lamp or lanthorn be made air-tight on the sides, 
 and furnished with apertures to admit the air, it will 
 not communicate flame to the outward atmosphere." 
 
8 DISCOVERY OH. 
 
 Davy might have made a fortune by his discovery, 
 by taking out a patent for the invention of the safety- 
 lamp, but he refused to do so. One of his friends, Mr. 
 John Buddie, who urged him on one occasion to secure 
 this recompense for his investigations and their result, 
 said : "I felt that he did not contemplate any pecuniary 
 reward ; and in a private conversation I remonstrated 
 with him on the subject. I said ' You might as well 
 have secured this invention by a patent, and received 
 your five or ten thousand a year from it.' Davy's reply 
 was, * No, my good friend, I never thought of such a 
 thing: my sole object was to serve the cause of humanity, 
 and if I have succeeded, I am amply rewarded in the 
 gratifying reflection of having done so. 5 ' 
 
 When Dr. Roux, Director of the Pasteur Institute 
 in Paris, was awarded the Osiris Prize of 4000 for the 
 discovery of the " anti-diphtheria serum," which has 
 been the means of saving the lives of many thousands 
 of children, he made over the whole of the money to the 
 institute of which he is the head, although he is 
 relatively a poor man. The founder of the prize, M. 
 Osiris, one day asked him why he had given the money 
 to the institute. "All that I am," replied Dr. Roux, 
 " I owe to the Pasteur Institute, for all my experiments 
 and discoveries have been made there. Besides, the 
 Institute is very poor, for we have no income except 
 what we make by the sale of serums, and though that 
 brings in enough to keep the establishment going, some 
 fresh remedy may any day be discovered, in which case 
 I fear the Institute would have to close its doors for 
 want of funds." The millionaire said nothing at the 
 time, but at his death, it was found that he had left 
 the bulk of his wealth, amounting to nearly one and a 
 quarter million pounds, to the Pasteur Institute, as a 
 
i OUTLOOK AND ENDEAVOUR 9 
 
 token of admiration for the scientific attainments and 
 self-abnegation of its director. 
 
 A correspondent asked Newton's permission to publish 
 in the Philosophical Transactions of the Royal Society, the 
 solutions, which Newton had sent him, of some mathe- 
 matical problems. Newton was at a time of life his 
 age was about twenty-seven when most men wish to 
 obtain credit for their work, but he particularly asked 
 that no mention should be made of his name in connec- 
 tion with this and like matters. " For I see not," he 
 added, " what there is desirable in public esteem were 
 I able to acquire and maintain it. It would perhaps 
 increase my acquaintance, the things which I chiefly 
 study to decline." 
 
 Newton was, indeed, never hasty in announcing his 
 discoveries, and had none of the spirit of rushing into 
 print to claim priority to which some investigators 
 attach so much importance. After he had invented the 
 reflecting telescope in 1668, he allowed the instrument to 
 lie by him for several years before its existence became 
 known to some of the fellows of the Royal Society who 
 induced him to send it to the Society, where it is now 
 carefully preserved. His important observations of the 
 compound nature of sunlight, a beam of which he 
 decomposed by passing it through a glass prism, were 
 not communicated to the Society until 1672, though 
 they were made before the invention of the reflecting 
 telescope ; and his discovery of the law of gravitation 
 was completed several years before Halley knew of it 
 and was able to make it known to the world. 
 
 What, then, are the motives of scientific work, if the 
 praise and rewards of the world have no meaning ? 
 Chiefly love of knowledge and the joy of discovery ; 
 and possessing these things the man of science faces 
 
10 DISCOVERY CH. 
 
 boldly all difficulties and is undaunted by danger. 
 During an epidemic of cholera in Paris in 1865, Pasteur 
 for a time undertook the study of the disease above 
 the cholera ward of a hospital. Henri Saint Claire 
 Deville once said to him, " Studies of that sort require 
 much courage." " What about duty ? " said Pasteur 
 simply. Danger is disregarded by the man of science 
 as by the soldier when duty calls ; and the spirit of 
 both is reflected in the words of the battle-hymn : 
 
 Grant that with zeal and skill this day I do 
 
 What me to do behoves, what thou command' st me to : 
 
 Grant that I do it sharp at moment fit, 
 
 And, when I do it, grant me good success in it. 
 
 Huxley was a warrior of science throughout his life. 
 When he was thirty-one years of age, while awaiting the 
 birth of his first child, on December 31, 1856, he entered 
 in his journal his ambitions for the future. 
 
 To smite all humbugs, however big ; to give a nobler tone to 
 science ; to set an example to abstinence from petty personal 
 controversies, and of toleration for everything but lying ; to be 
 indifferent as to whether the work is recognised as mine or not, 
 so long as it is done : are these my aims ? 1860 will show 
 
 Wilt shape a noble life ? Then cast 
 No backward glances to the past. 
 And what if something still be lost ? 
 Act as new-born in all thou dost. 
 What each day wills, that shalt thou ask ; 
 Each day will tell its proper task ; 
 What others do, that shalt thou prize, 
 In thine own work thy guerdon lies. 
 This above all : hate none. The rest 
 Leave it to God. He knoweth best. 
 
 That such a prayer as this should be offered up at 
 the most anxious moment of his life, by one who was 
 thought to be the apostle of materialistic knowledge, 
 
i OUTLOOK AND ENDEAVOUR 11 
 
 shows how mistaken is the common impression that 
 close devotion to science weakens the spiritual side of a 
 man. The life consecrated to the study of Nature 
 must by this purpose alone have aims and ideals as high 
 as any which stimulate human endeavour. No great 
 work whether in the natural or in the spiritual world 
 can be accomplished without noble aspiration. " Blessed 
 is he," said Pasteur, " who carries with him a God, an 
 ideal, and obeys it ; ideal of art, ideal of science, ideal 
 of the gospel virtues ; therein lie the springs of great 
 thoughts and great actions ; they all reflect light from 
 the Infinite." 
 
 All who labour to extend knowledge and establish 
 truth are making for righteousness ; though they sail 
 in different seas they have the same guiding star, and 
 it is set so far away in infinity that compared with its 
 distance their paths are one. Let, then, the captain 
 of each ship shape his own course and not concern 
 himself with the tracks of other navigators ; the new 
 lands encountered may present very diverse characters, 
 but each explorer is expected to describe only what 
 comes within his own range of observation. He can 
 know nothing of what pioneers in other directions have 
 seen, but with hope at the helm and truth at the prow 
 he strikes the course for which his ship was chartered, 
 even when it seems to be crossing the tracks of other 
 vessels or landing him upon the rocks. This is the 
 spirit in which the scientific investigator sets out for 
 unknown lands. " When I am in my laboratory," said 
 Pasteur, " I begin by shutting the door on materialism 
 and on spiritualism ; I observe facts alone ; I seek but 
 the scientific conditions under which life manifests itself." 
 
 Facts which appear to be opposed to prevailing belief 
 or theory are often reached in science, but if they 
 
12 DISCOVERY OH. 
 
 stand unaltered after being subjected to rigorous and 
 critical examination they must be adhered to and the 
 belief or theory abandoned. In the world of natural 
 knowledge, no authority is great enough to support a 
 theory when a crucial observation has shown it to be 
 untenable. Scientific work must thus be carried on 
 with an open mind, uninfluenced by preconceived ideas, 
 critical of its own observations, cautious in arriving at 
 conclusions from them, and ready to revise any state- 
 ment which has not stood the test of further experiment 
 or reasoning. 
 
 The philosopher should be a man willing to listen to every 
 suggestion, but determined to judge for himself. He should not 
 be biassed by appearances ; have no favourite hypothesis ; be of 
 no school ; and in doctrine have no master. He should not be a 
 respecter of persons, but of things. Truth should be his primary 
 object. If to these qualities be added industry, he may indeed 
 hope to walk within the veil of the temple of Nature. Faraday. 
 
 Scientific truth is not won by prayer and fasting, but 
 by patient observation and persistent inquiry. Nature, 
 like the rich man of the parable, requires importunate 
 pleading before she will bestow any of her riches upon 
 a suppliant at her temple, Every mite of knowledge 
 has almost to be wrested from her ; and it takes many 
 such contributions to form a principle or theory which 
 will constitute the stimulus by which further endeavour 
 is sustained. 
 
 The world little knows how many of the thoughts and theories 
 which have passed through the mind of a scientific investigator 
 have been crushed in silence and secrecy by his own severe 
 criticism and adverse examinations ; that in the most successful 
 instances not a tenth of the suggestions, the hopes, the wishes, 
 the preliminary conclusions have been realised. Faraday. 
 
 It is necessary to believe in the holiness of scientific 
 work in order to persevere to the end ; for without the 
 
i OUTLOOK AND ENDEAVOUR 13 
 
 encouragement which such belief gives, many investiga- 
 tors would fall by the wayside. But no man of science 
 who has put his hand to the plough of research ever 
 turns back. He knows that he is at work in a broad 
 field and that not only will he be judged by the straight- 
 ness of his furrows, but also that he is preparing a tilth 
 for a seedtime and harvest of knowledge of which the 
 chief benefit will be to others. He does not measure 
 his task by his wage, but performs it faithfully because 
 of its worthiness and his interest in it. 
 
 If I may speak of the objects I have had more or less definitely 
 in view, they are briefly these : To promote the increase of 
 natural knowledge and to forward the application of scientific 
 methods to all the problems of life, to the best of my ability, in 
 the conviction, which has grown up with my growth, and 
 strengthened with my strength, that there is no alleviation of the 
 sufferings of mankind except veracity of thought and action, 
 and the resolute facing of the world as it is when the garment of 
 make-believe with which pious hands have hidden its uglier 
 features has been stripped off. Huxley. 
 
 A subject which will promote the development of 
 such noble ambitions as these should be included in the 
 education of every civilised being ; yet science is still 
 the Cinderella in the house of education. 
 
 I do think that the study of natural science is so glorious a 
 school for the mind that, with the laws impressed on all created 
 things by the Creator, and the wonderful unity and stability of 
 matter and the forces of matter, there cannot be a better school 
 for the education of the mind. Faraday. 
 
 The study of Nature is elevating, and its material 
 value is of the highest, yet it is deplorably neglected,with 
 the result that only very rarely is the simplest scientific 
 subject referred to accurately in the works of literary 
 men. Our guides and counsellors, not only in the 
 periodical press, but also in less ephemeral publications, 
 
14 DISCOVERY OH. 
 
 are, in the great majority of cases, unaware of the most 
 obvious facts and phenomena of Nature, and have no 
 acquaintance with the most elementary vocabulary of 
 science. In everything that relates to the material 
 universe around them, they are blind leaders of the 
 blind ; and they call their darkness light. They are 
 indifferent to the wonderful growth and extent of scien- 
 tific knowledge, and live in a paradise in which rounded 
 phrases and curious fancies are of more importance than 
 actual facts. In such a world a one-eyed man can be 
 king. A more enlightened view will only be obtained 
 when it is realised that an educated man must know 
 something of science as well as of literature. 
 
 The supercilious manner in which science is often 
 treated by men nourished in a purely literary atmo- 
 sphere is illustrated by an incident related in Lord 
 Morley's Life of Gladstone. In 1877 Lord Morley, with 
 Mr. Gladstone, Huxley and Lord Playfair, were staying 
 with Lord Avebury (Sir John Lubbock), at High Elms, 
 in Kent, and on the Sunday afternoon the party went 
 up to the neighbouring village of Downe to visit Darwin. 
 
 The illustrious pair, born in the same year, had never met 
 before. Mr. Gladstone as soon as seated took Darwin's interest 
 in lessons of massacre for granted, and launched forth his thunder- 
 bolts [against Turkish atrocities] with unexhausted zest. His 
 great, wise, simple, and truth-loving listener, then, I think, busy 
 on digestive powers of the Drosera in his green-house, was 
 intensely delighted. When we broke up, watching Mr. Glad- 
 stone's erect figure as he walked away, Darwin, shading his eyes 
 with his hand against the evening rays, said to me in unaffected 
 satisfaction, " What an honour that such a great man should 
 come to visit me ! " Too absorbed in his own overwhelming 
 conflict with the powers of evil, Mr. Gladstone makes no mention 
 of his afternoon call, and only says of the two days that "he found 
 a notable party, and much interesting conversation," and that 
 he " could not help liking " one of the company, then a stranger 
 to him. Lord Morley. 
 
i OUTLOOK AND ENDEAVOUR 15 
 
 Like many other statesmen and men of letters, 
 Mr. Gladstone was unaware of the greatness of his 
 scientific contemporaries. " Who is Cuvier ? " asked 
 Louis Philippe, King of the French, when told that this 
 illustrious naturalist, founder of comparative anatomy 
 and palaeontology, and the most celebrated man of 
 science in France at the time, was dead. " Monsieur 
 Cuvier ? I believe he was one of the gentlemen employed 
 at the Jardin des Plantes," was the courtier's response. 
 A similar story is told of the last emperor of the French, 
 Napoleon III., who was asked by a German guest to be 
 introduced to the eminent physiologist, Claude Bernard. 
 " Claude Bernard ? Who is Claude Bernard ? " the 
 Emperor asked. " He is the most distinguished savant 
 in your Majesty's dominions," was the reply. Truly 
 a man of science is not without honour except in his 
 own country and among his own people. 
 
 It is time to understand that no man can now be con- 
 sidered to have received a liberal education unless he 
 has some acquaintance with the principles of science ; 
 and that the works of Darwin and Faraday are as worthy 
 of national honour as those of Tennyson and Scott. 
 The training which ends in literary culture without 
 science is just as incomplete as one which promotes 
 scientific knowledge without the power of clear expression. 
 
 That man, I think, has had a liberal education, who has been 
 so trained in youth that his body is 'the ready servant of his will, 
 and does with ease and pleasure all the work that, as a mechanism, 
 it is capable of; whose intellect is a clear, cold, logic engine 
 with all its parts of equal strength, and in smooth working order ; 
 ready, like a steam engine, to be turned to any kind of work, 
 and spin the gossamers as well as forge the anchors of the mind ; 
 whose mind is stored with a knowledge of the great and funda- 
 mental truths of Nature and of the laws of her operations ; and 
 who, no stunted ascetic, is full of life and fire, but whose passions 
 
16 DISCOVERY CH. 
 
 are trained to come to heel by a vigorous will, the servant of a 
 tender conscience ; who has learned to love all beauty, whether 
 of Nature or of art, to hate all vileness, and to respect others as 
 himself. Huxley. 
 
 Do you wish education to cultivate supreme regard for 
 truth ?- Then let it include the study oTNature, for in 
 dealings with her every false coin is inexorably nailed to 
 the counter. Do you wish to create a sense of moral 
 responsibility ? Then learn from Nature that every 
 act has a consequence, and every sin a penalty. Is a 
 habit of mind required which will not be deceived by 
 the noisy huckster of sensational statements ? Then 
 give attention to training in scientific method, by which 
 a critical faculty is developed that enables fact to be 
 distinguished from fable and is cautious in arriving at 
 conclusions. Do you believe in the dignity of work and 
 the duty of self-sacrifice ? Then turn to science, which 
 demands devoted labour for the benefit of others. Are 
 satisfaction with the superficial, and a desire for con- 
 tinuous excitement to be the characteristics of the new 
 generation ? If not, see that interest is aroused in the 
 nobler views of life opened by scientific knowledge. 
 Regard for veracity, patience, logical thought, responsi- 
 bility, discipline and original work, are all taught 
 by the study of science ; and these attributes are as 
 desirable in every one of us as in the investigator whose 
 life is an exemplar of them. 
 
 My success as a man of science, whatever this may have amounted 
 to, has been determined, as far as I can judge, by complex and 
 diversified mental qualities and conditions. Of these, the most 
 important have been the love of science, unbounded patience 
 hi long reflecting over any subject, industry in observing and 
 collecting facts, and a fair share of invention as well as of com- 
 mon sense. With such moderate abilities as I possess, it is truly 
 surprising that I should have influenced to a considerable extent 
 the belief of scientific men on some important points. Darwin. 
 
i OUTLOOK AND ENDEAVOUR 17 
 
 The pleasure derived from the discovery of some secret 
 of Nature unknown before except to the architect of the 
 universe surpasses all the rewards the world can give. 
 It is a compensation which takes the place of worldly 
 riches and enables unselfish work to be done from which 
 others often make commercial gain. While men engaged 
 in other pursuits lose their interest in later life, in the 
 man of science the love of Nature and the desire for new 
 knowledge is eternal. Dr. Weir Mitchell relates that 
 once, at his table, some one- asked that ever-happy 
 naturalist, Joseph Leidy, if he were never tired of life. 
 " Tired ! " he said ; " Not so long as there is an 
 undescribed intestinal worm, or the riddle of a fossil 
 bone, or a rhizopod new to me." These subjects may 
 seem uninspiring, but the words reveal the spirit of the 
 ardent lover of a mistress of unfading charm. Of this 
 great student and teacher, the following lines were 
 spoken on the occasion of the inauguration of a memorial 
 lectureship in his honour : 
 
 The wisest man could ask no more of fate 
 Than to be simple, modest, manly, true, 
 Safe from the many, honoured by the few ; 
 
 Nothing to count in world, or church, or State, 
 
 But inwardly in secret to be great ; 
 To feel mysterious Nature ever new, 
 To touch, if not to grasp, her endless clue, 
 
 And learn by each discovery how to wait, 
 
 To widen knowledge and escape the praise ; 
 Wisely to teach because more wise to learn ; 
 
 To toil for science, not to draw men's gaze, 
 But for her love of self denial stern ; 
 
 That such a man could spring from our decays 
 Fans the soul's nobler faith until it burn. 
 
 Prof. E. F. Smith. 
 
 Testimony to the complete satisfaction and perennial 
 interest derived from the study of Nature has been given 
 
 G.D. B 
 
18 DISCOVERY CH. 
 
 by many men of science. " In my laboratory," said 
 Robert Boyle, " I find that water of Lethe which causes 
 that I forget everything but the joy of making experi- 
 ments." This great natural philosopher is said to have 
 remarked that he feared death only because after it he 
 would know all things, and no longer have the delight 
 of making discoveries. Dumas, the renowned French 
 chemist, was a man of affairs as well as a man of science, 
 yet he said : 
 
 The recollections of an already long life have permitted me to 
 become acquainted with a great variety of personages. And if 
 I call on memory to picture to me how the type of true happiness 
 is realised on earth I do not see it under the form of the powerful 
 man clothed in high authority, nor under that of the rich man 
 to whom the splendours of luxury and the delicacies of well- 
 being are granted, but under that of the man of science, who 
 consecrates his life to penetrating the secrets of Nature and to the 
 discovery of new truths. J. B. A. Dumas. 
 
 On the occasion of his eighty-ninth birthday, the 
 biology class at the University of Colorado sent Dr. 
 Alfred Russel Wallace a greeting, and to it the veteran 
 naturalist replied : 
 
 The wonders of Nature have been the delight and solace of my 
 life. From the day when I first saw a bee-orchis in ignorant 
 astonishment, to my first view of the grand forests of the Amazon ; 
 thence to the Malay Archipelago, where every fresh island with its 
 marvellous novelties and beauties was an additional delight 
 Nature has afforded me an ever-increasing rapture, and the 
 attempt to solve some of her myriad problems an ever-growing 
 sense of mystery and awe. And now, in my wild garden and 
 green-house, the endless diversities of plant life renew my enjoy- 
 ments ; and the ever-changing pageants of the seasons impress 
 me more than ever in my earlier days. I sincerely wish you all 
 some of the delight in the mere contemplation of Nature's 
 mysteries and beauties which I have enjoyed, and still enjoy. 
 Dr. A. Russel Wallace. 
 
i OUTLOOK AND ENDEAVOUR 19 
 
 Darwin, with whom Wallace shared the honour of 
 building up the great principle of natural selection as 
 the prime cause of organic evolution, found equal 
 pleasure in Nature to the end of his life ; and his chief 
 regret was that he had not been able to contribute 
 more to natural knowledge and human happiness. 
 " As for myself," he said, " I believe that I have 
 acted rightly in steadily following and devoting my 
 life to science. I feel no remorse from having com- 
 mitted any great sin, but have often and often regretted 
 that I have not done more direct good to my fellow 
 creatures." 
 
 So little done, so much to do, is the first and last 
 thought of the man of science. A short time before his 
 death, Sir Isaac Newton expressed the memorable 
 sentiment : " I do not know what I may appear to the 
 world, but to myself I seem to have been only like a boy 
 playing on the sea-shore, and diverting myself in now 
 and then finding a smoother pebble or a prettier shell 
 than ordinary, whilst the great ocean of truth lay all 
 undiscovered before me." 
 
 This was Newton's estimate of his work, yet it is 
 related that when the Queen of Prussia asked Leibnitz 
 his opinion of Newton, Leibnitz said that taking mathe- 
 maticians from the beginning of the world to the time 
 when Newton lived, what he had done was much the 
 better half. 
 
 After Sir William Herschel had discovered the planet 
 Uranus he was commanded by King George III. to 
 attend the court with his telescope. Writing to his 
 sister Caroline he said : " Nothing now is talked of bub 
 what they call my great discoveries. Alas ! this shows 
 how far they are behind when such trifles as I have done 
 are called great. Let me but get at it again ; I will 
 
20 DISCOVERY CH. 
 
 make such telescopes and see such things that is, I will 
 endeavour to do so." 
 
 The less a man knows, the more content he is with his 
 intellectual capacity and outlook : it requires a great 
 man to realise the imperfections of his knowledge. At 
 the jubilee of Lord Kelvin, celebrated at the University 
 of Glasgow in 1896, representatives of " light and lead- 
 ing " from all parts of the world assembled to do honour 
 to him. In science and in invention his work belongs 
 to the front rank of results of human thought and 
 ingenuity. Yet what did Lord Kelvin say in reply to 
 the congratulations expressed upon his service in the 
 cause of scientific progress ? 
 
 " One word characterises the most strenuous of the efforts for 
 the advancement of science that I have made perseveringly 
 during fifty-five years ; that word," he said, " is failure. I know 
 no more of electric and magnetic force, or of the relation between 
 ether, electricity and ponderable matter, or of chemical affinity, 
 than I knew and tried to teach to my students of natural philo- 
 sophy fifty years ago in my first session as Professor." Kelvin. 
 
 Far more than anyone else in his day and generation, 
 Lord Kelvin contributed to the advancement of science 
 and the application of natural knowledge to the use of 
 mankind ; yet in his mind the predominant idea was 
 not satisfaction at success but disappointment at the 
 failure of his persevering efforts during fifty years to 
 understand the omnipresent ether of the physicist and 
 the manner in which it is concerned in electric and mag- 
 netic forces. The achievement of ocean telegraphy, 
 the improvement of the compass and sounding-line, the 
 hundreds of papers on properties of matter, provide 
 sufficient justification for a score of scientific careers, 
 but to Lord Kelvin they seemed insignificant in com- 
 parison with the unsolved problem of the theory of matter 
 
i OUTLOOK AND ENDEAVOUR 21 
 
 which would unify them all. He knew that when the 
 key to the riddle of the relation between ether and matter 
 is discovered, mankind will be able to enter the treasure- 
 house in which Nature's secrets are stored. 
 
 Such men as Lord Kelvin are learners always, because 
 they realise that for one problem solved, one principle 
 discovered, one structure completely described, there 
 are a thousand of which they understand nothing. 
 
 All Nature is but art, unknown to thee 
 
 All chance, direction which thou canst not see ; 
 
 All discord, harmony not understood ; 
 
 All partial evil, universal good. Pope. 
 
 Man as a physical being is but a microscopic part of 
 the universe, yet his mind carries him ever upward, and 
 with spirit bold and unconquerable he seeks to reach 
 the summit of Mount Olympus. Infinite space remains 
 to humble his pride in spite of the knowledge he has 
 obtained of the starry heavens ; yet he pursues his 
 inquiries into the unknown, and his children's children 
 will continue the search. 
 
 As we conquer peak after peak we see in front of us regions full 
 of interest and beauty, but we do not see our goal, we do not see 
 the horizon ; in the distance tower still higher peaks, which will 
 yield to those who ascend them still wider prospects, and deepen 
 the feeling, the truth of which is emphasised by every advance in 
 science, that " Great are the Works of the Lord." Sir J. J. 
 Thomson. 
 
 It is said that Thales of Miletus, who was the first of 
 the Greeks to devote himself to the study of the stars, 
 was on one occasion so intent upon observing the heavens 
 that he fell into a well, whereupon a maidservant laughed 
 and remarked, " In his zeal for things in the sky he does 
 not see what is at his feet." Many men have been 
 laughed at since then for gazing heavenward when their 
 
22 DISCOVERY CH. i 
 
 minds might have been occupied with affairs of earth. 
 There will always be the mind that strives to reach to the 
 skies, and the scoffer who regards all such aspirations 
 as folly. 
 
 Two men stood looking through the bars, 
 One saw the mud, the other saw the stars. 
 
 
 
CHAPTER II 
 TRUTH AND TESTIMONY 
 
 The first and last thing that is demanded of genius is love 
 of truth. Goethe. 
 
 There is no lie in Nature ; no discords in the revelations 
 of science, in the laws of the Universe. C. Kingsley. 
 
 Nothing great in science has ever been done by men, 
 whatever their powers, in whom the Divine afflatus of 
 the truth-seeker was wanting. Huxley. 
 
 The greatest and noblest pleasure which men can have in 
 this world is to discover new truths ; and the next is 
 to shake off old prejudices. Frederick the Great. 
 
 New occasions teach new duties ; Time makes ancient 
 good uncouth ; 
 
 They must upward still and onward who would keep 
 abreast of truth. J. R. Lowell. 
 
 We cannot command veracity at will ; the power of seeing 
 and reporting truly is a form of health that has to be 
 delicately guarded. The penalty of untruth is untruth. 
 George Eliot. 
 
 // God held enclosed in His right hand all truth, and in 
 His left simply the ever-moving impulse towards 
 truth, although with the condition that I should eternally 
 err, and said to me, " Choose ! " / should humbly bow 
 before His left hand, and say, " Father, give \ Pure 
 truth is for Thee alone." G. E. Lessing. 
 
 DURING the celebration of the 250th anniversary of the 
 Royal Society in 1912, a commemorative service was 
 held in the ancient Abbey of Westminster, and the Right 
 Rev. the Dean of Westminster, Dr. H. E. Ryle, delivered 
 
24 DISCOVERY CH. 
 
 a short address, taking for his text the words : " Truth 
 abideth, and is strong for ever, she liveth and conquereth 
 for evermore . . . Blessed be the God of truth . . . 
 And all the people then shouted, and said, Great is truth 
 and strong above all things " (I. Esdras, iv. 38, 40, 41). 
 The familiar proverb, Magna est veritas, et praevakbit is 
 a slightly altered rendering of this text ; and no more 
 appropriate inspiration than it provides could be found 
 for an address to an assembly of men of science. For 
 the love of truth is the chief characteristic of the scientific 
 mind. 
 
 It is the man of science, eager to have his every opinion 
 regenerated, his every idea rationalised, by drinking at the foun- 
 tain of fact, and devoting all the energies of his life to the cult of 
 truth, not as he understands it, but as he does not understand 
 it, that ought properly to be called a philosopher. To an earlier 
 age knowledge was power merely that and nothing more to 
 us it is life and the summum bonum. C. S. Peirce. 
 
 In the pursuit of truth the man of science spends his 
 days ; and for the defence of truth he is prepared to 
 stand against the world. From his earliest instruction 
 in the laboratory or the field to the end of his life, the 
 student of science is learning that by nothing but 
 faithful observation and truthful record can a satis- 
 factory conclusion be reached. Regard for truth becomes 
 part of his nature, and the investigations which lead to 
 it purify his life. Read the biography of any man who 
 gained distinction by his studies of Nature, and you will 
 find that he valued truthfulness above all other qualities 
 of a scientific mind. " There is," said Lord Kelvin, 
 " one thing I feel strongly in respect to investigation in 
 physical or chemical laboratories it leaves no room 
 for shady, doubtful distinctions between truth, half- 
 truth, whole falsehood. In the laboratory everything 
 tested or tried is found true or not." 
 
ii TRUTH AND TESTIMONY 25 
 
 A truthful mind is necessary for the discovery of 
 truth in Nature. There is often a vast difference 
 between the result an investigator expects to find and 
 what he does obtain, but he must put his hopes aside 
 and follow the new light if he is to be a worthy contributor 
 to scientific knowledge. By this method alone are the 
 conclusions and principles reached which form the 
 refined gold of science. Advance is made by the study 
 of cases which cannot be embraced by a general principle, 
 by the possession of an eye to detect exceptions and of 
 a mind willing to examine them instead of putting them 
 aside because they are not in harmony with pre-con- 
 ceived ideas. 
 
 A particular characteristic of Charles Darwin was the 
 receptive mind with which he faced Nature, and the 
 power of seeing exactly how to deal with variations from 
 a general rule. Sir Francis Darwin relates that his 
 father had a favourite gardener, to whom he used to 
 predict the result of an experiment. When, as often 
 happened, the contrary result came out, it was only 
 natural that the gardener should be pleased. On the 
 other hand, Darwin, though he was disappointed, would 
 say as he left the green-house, " The little beasts are 
 doing just what I did not want them to do." He was 
 not the least upset and very often this type of failure 
 heralded quite a new discovery. His love of truth 
 enabled him immediately to abandon his own hypotheses 
 when they ceased to be supported by observation, and 
 to proceed to inquire into the cause of the unlooked-for 
 result. 
 
 Exceptions to rules are welcomed by a scientific 
 investigator not only because the rules have been tested 
 by them and found wanting, but also because they show 
 that there is still further knowledge to be gained. In 
 
26 DISCOVERY CH. 
 
 this respect the attitude of the man of science differs 
 from that of ordinary life ; for most people instinctively 
 cherish convictions based upon experience of a few 
 cases or conditions and are adroit in avoiding evidence 
 contrary to what they wish to believe. They cannot 
 understand the habit of mind which looks upon all truth 
 as relative and temporary, and rejoices at the disclosure 
 of a fact that refuses to fall within the limits of an 
 accepted principle. It may be impossible for human 
 intelligence to comprehend absolute truth, but it is 
 possible to observe Nature with an unbiassed mind and 
 to bear truthful testimony of things seen.1 
 
 To thine ownself be true ; 
 And it must follow, as the night the day, 
 Thou canst not then be false to any man. Shakespeare. 
 
 " Nature," once remarked Goethe to a friend ; 
 " Nature knows no trifling ; she is always sincere, 
 always serious, always stern ; she is always in the right, 
 and the errors and mistakes are invariably ours." N* 
 one realises this more fully than the scientific experi- 
 menter or observer. He looks at Nature's countenance, 
 and as a sworn witness before the tribunal of reality, 
 testifies to what is revealed to him. Upon him is the 
 responsibility of recording exactly what he sees, and by 
 his gaze alone can that knowledge be obtained which 
 will subdue Nature to the rule of the human intellect. 
 Much that he sees may not be understood, but unless 
 he has the love of truth his vision will be distorted. 
 Hear what a great physicist says of the essential attri- 
 butes of a scientific observer and the conquests to which 
 they lead : 
 
 I value in a scientific mind, most of all, that love of truth, 
 that care in its pursuit, and that humility of mind which makes 
 the possibility of error always present more than any other 
 
n TRUTH AND TESTIMONY 27 
 
 quality. This is the mind which has built up modern science to 
 its present perfection, which has laid one stone upon the other 
 with such care that it to-day offers to the world the most complete 
 monument to human reason. This is the mind which is destined 
 to govern the world in the future, and to solve the problems per- 
 taining to politics and humanity as well as to inanimate nature. 
 It is the only mind which appreciates the imperfections of the 
 human reason, and is thus careful to guard against them. It 
 is the only mind that values the truth as it should be valued and 
 ignores all personal feeling in its pursuit. Prof. H. A. Rowland. 
 
 This is the type of mind a scientific training is intended 
 to cultivate ; and it is easier for a camel to pass through 
 a needle's eye than it is to enter into the kingdom of 
 science without it. We use the simile with all reverence 
 in this connection, because science is an uplifting gospel 
 as well as a revelation. Huxley described himself as 
 " almost a fanatic for the sanctity of truth." Truthful- 
 ness, in his eyes, was the cardinal virtue without which 
 neither science nor society could possess stability. The 
 motive of all scientific work is to arrive at the truth, 
 and Huxley's life was the apotheosis of this passion for 
 veracity. 
 
 If absolute loyalty to truth, involving complete self-abnegation 
 in face of the evidence, be the ideal aim of the scientific inquirer, 
 there have been few men in whom that ideal has been so perfectly 
 realised as in Huxley. If ever he were tempted by some fancied 
 charm of speculation to swerve a hair's breadth from the strict 
 line of fact, the temptation was promptly slaughtered and made 
 no sign. For intellectual integrity he was a spotless Sir Galahad. 
 I believe there was nothing in life which he dreaded so much as 
 the sin of allowing his reason to be hoodwinked by personal 
 predilections, or whatever Francis Bacon would have called 
 " idols of the cave." John Fiske. 
 
 The love of truth is the beginning and the end of 
 wisdom. It is with the astronomer as he searches the 
 skies from his watch tower and it animates the naturalist 
 as he scrutinises muds gathered from the ocean bed ; it 
 
28 DISCOVERY OH. 
 
 is the heart of scientific life, a stimulus to high endeavour 
 and a standard of righteousness. In this spirit must 
 Nature be approached, and by it is admission gained to 
 the temples of her learning. 
 
 You come to the chest of knowledge. It is shut, it is bolted, 
 but . . . you have the key ; put it in steadily and home. But 
 what is the key ? It is the love of truth ; neither more or less ; 
 no other key opens it ; no false one, however cunning, can pick 
 that lock ; no assault of hammer, however stout, can force it 
 open ; but with its own key, a little child may open it ; often 
 does open it. John Brown. 
 
 In northern mythology, the well of wisdom was 
 situated at one end of a rainbow. There also is truth 
 hidden, and he who would discover either must adventure 
 by himself into the unknown. Though perfect wisdom 
 and absolute truth are as unattainable as the rainbow- 
 foot, the effort to reach them brings a rich reward. No 
 two people ever see the same rainbow ; and to each of 
 us, therefore, is given a different goal, but whether we 
 set out towards it or not depends upon ourselves. 
 Wisdom will not come to us, but we may gain it by 
 experience ; truth will not wait on our command, and 
 yet will accompany us always while we are faithful to 
 her. We may catch only a glimpse of her wondrous 
 beauty after a life of devoted service, but there is even 
 more satisfaction in the anticipation of this vision than 
 in the actual attainment of the heart's desire. 
 
 It is the successful, or even the unsuccessful, pursuit of truth 
 which gives happiness to each generation of scientific men, and 
 not the value of the truth itself the energy, the doing, not the 
 thing done. If a time could arrive when all was known, when 
 there could not be a new investigation or experiment, our keenest 
 pleasure would be at an end. We may therefore feel happy in 
 the thought of how much is still unknown. A. G. Vernon 
 Harcourt. 
 
ii TRUTH AND TESTIMONY 29 
 
 The pursuit of truth is likely to last as long as the 
 generations of mankind, for rightly understood it signifies 
 the quest for knowledge. In scientific truth there is 
 no finality, and there should, therefore, be no dogmatism. 
 When this is forgotten, then science will become stagnant, 
 and its high-priests will endeavour to strangle new 
 learning at its birth as has been done by the guardians 
 of orthodoxy throughout the ages. 
 
 Since life began upon the earth, there has been a 
 gradual development into new and nobler forms. In 
 size and strength, many animals are mightier than man ; 
 but he is supreme over them because of his knowledge. 
 Every conquest of science brings the human race nearer 
 the day when it will have complete control over the 
 forces of Nature and be able to use them for its own 
 purposes. There must be no resting satisfied with 
 achievements, but persistent endeavour to enter the 
 unknown and bring back trophies from it. The talents 
 with which we are entrusted must be given up with 
 increase ; so that, as one generation succeeds another, 
 its store of knowledge shall be greater. The man who 
 neglects to assist the advancement of his race so far as 
 in him lies is like the slothful servant who buried his 
 talent in the ground ; and he should receive a like 
 condemnation. 
 
 If we merely pass on what we receive the human race 
 cannot develop onward and upward until man is " a little 
 lower than the angels." We shall be like certain little 
 brachiopods or " lamp-shells," which have remained 
 unchanged in form for millions of years, being practi- 
 cally the same in the seas of to-day as they were in those 
 of early geological times. While throughout countless 
 ages the living world has been unfolding from lower 
 to higher forms of life, these molluscan types have 
 
30 DISCOVERY CH. 
 
 merely carried on their kind, benefiting nothing by the 
 past, gaining nothing for the future. That is not the 
 kind of life by which evolution has proceeded. It is 
 the desire to learn by experience not only our own 
 experience but also the experience of others that has 
 raised the human race to its present position. We owe 
 it to ourselves and to future generations to do what we 
 can to secure a further increase of that knowledge by 
 which our redemption from brute creation has been 
 accomplished. 
 
 Let knowledge grow from more to more 
 
 But more of reverence in us dwell. Tennyson. 
 
 The recognition that knowledge of the physical 
 universe is only the bud of a flower which can never 
 be seen in its perfection is the salvation of science. 
 Nature acknowledges no exclusive claims to truth or 
 right of dictatorship in her name either to this generation 
 or the next. The scientific man has to work for truth 
 so far as her ways can be comprehended by him, but he 
 is never more than a trustee for posterity, and has no 
 authority to define the functions or limit the freedom 
 of those who follow him. When men believe that 
 complete truth has been revealed to them they restrain 
 inquiry and persecute those who fail to see the same 
 light. This position should never be taken in science, 
 which invites investigation, welcomes criticism, and 
 rejoices at new truths to supersede or supplement 
 the old. 
 
 When men are striving for the discovery of truth in its various 
 manifestations, they learn that it is by correcting the mistakes 
 of preceding investigators that progress is made, and they have 
 charity for criticism. Hence persecution for difference of opinion 
 becomes an absurdity. The labours of scientific men are forming 
 a great body of doctrine that can be appealed to with confidence 
 
ii TRUTH AND TESTIMONY 31 
 
 in all countries. Such labours bring people together, and tend 
 to break down national barriers and restrictions. The scientific 
 creed is constantly growing and expanding, and we have no 
 fears, but rejoice at its growth. We need no consistory of bishops, 
 or synod of ministers, to tell us what to believe. Everything is 
 open to investigation and criticism. Prof. Asaph Hall. 
 
 Science does not say " Be my brother, or I will kill 
 you," but, " Follow me, and light shall be given you." 
 It does not ask for the acceptance of any statement or 
 principle purely as matters of faith, but as truthful 
 records or reasonable conclusions, capable of verification 
 by all who care to investigate them independently. 
 
 Essential to a scientific spirit is a temper of mind 
 which seeks for conclusions, but does not jump at them 
 which, as the late Lord Derby once ,said, is equally 
 opposed to the stupid incredulity of ignorance that refuses 
 to accept any idea which is not familiar ; to the reveren- 
 tial credulity which accepts as true any statement 
 coming down from old or high authority ; and to the 
 careless indiiferentism which, so long as a theory looks 
 and sounds well, and especially if it flatters some 
 previously existing feeling of prejudice, does not care 
 on what foundation of reality that theory rests. The 
 scientific mind asks for reasons for its beliefs, and is 
 unwilling to express an opinion upon any conclusion 
 without personal knowledge of the evidence upon which 
 it is based. It distinguishes between the statements 
 made by others and the conviction derived from experi- 
 ence ; and it is impatient of the petty differences which 
 often make contentions for sects and party politicians. 
 
 Call belief 
 Belief indeed, nor grace with such a name 
 
 The easy acquiescence of mankind 
 In matters nowise worth dispute, since life 
 
 Lasts merely the allotted moment, Browning. 
 

 32 DISCOVERY CH. 
 
 In the discussion of political questions, prejudice 
 and party determine the view taken, and facts are selected 
 and exploited not so much with the object of arriving 
 at the truth as to confound the other side or support 
 a particular opinion. The vulgar abuse and vapid 
 sentiment which are the stock-in-trade of many political 
 writers and speakers provoke only contempt in the 
 minds of thinking men. A politician may place party 
 before truth, a diplomatist will conceal it on behalf of his 
 country, and an advocate in the interests of his client, 
 but it is the duty of a man of science to strive to 
 attain truth at all costs. 
 
 In direct opposition to the narrowness of thought, which views 
 all subjects through the distorting mirage of party prejudice, 
 stands the absolute freedom of mind of the man of science, who 
 knows, or ought to know, nothing of party, and stands with open 
 arms to welcome truth in however strange or unexpected guise 
 she may present herself. In his writings the man of science 
 has no lower aim than the diffusion of truth so far as it is known, 
 and no desire to make converts to any opinion or party. As 
 opposed to the finality of party opinions, he proclaims that 
 truth is but very partially attained by man on any subject, for 
 we can see truth only imperfectly, as she appears altered by the 
 perspective of our own standpoint. Sir William Huggins. 
 
 Most scientific work must be done without recognition 
 or expectation of reward. Many men who devote their 
 lives to the extension of knowledge continually find 
 themselves without the means of obtaining the instru- 
 ments or other material necessary for the pursuit of 
 their researches. On the principle of " Nothing suc- 
 ceeds like success," assistance is offered when the work 
 for which it would have been of service has been 
 accomplished or to the man who is independent of it, 
 instead of to the earnest investigator whose limited 
 means leave little for science when social necessities 
 
ii TRUTH AND TESTIMONY 33 
 
 have been satisfied. Newton himself was, at one time 
 of his life, in such poverty that he asked to be excused 
 from the weekly payment of one shilling which the 
 Royal Society required of its members. 
 
 Patronage is not wanted, but encouragement in a 
 practical form may be of the greatest service if given 
 early. Bis dat qui cito dat is particularly applicable to 
 the needs of young men trained for scientific investiga- 
 tion and eager to pursue it if the means which will permit 
 them to do so are provided. The position is like that 
 stated in Dr. Johnson's celebrated letter to Lord 
 Chesterfield concerning his Dictionary. Johnson worked 
 for seven years " without one act of assistance, one word 
 of encouragement, or one smile of favour " from his 
 lordship, who, however, when the Dictionary was on 
 the eve of publication, made professions of friendship in 
 the hope, it is said, that the work would be dedicated 
 to him. Johnson wrote : 
 
 Is not a patron, my lord, one who looks with unconcern on a 
 man struggling for life in the water, and when he has reached 
 ground, encumbers him with help ? The notice which you have 
 been pleased to take of my labours, had it been early, had been 
 kind ; but it has been delayed till I am indifferent, and cannot 
 enjoy it ; till I am solitary, and cannot impart it ; till I am 
 known, and do not want it. I hope it is no very cynical asperity, 
 not to confess obligations where no benefit has been received, or 
 to be unwilling that the public should consider me as owing that 
 to a patron, which Providence has enabled me to do for myself. 
 
 When men of science ask for funds for scientific 
 research they do not wish to bury the talents they 
 receive or to derive personal profit from them. What- 
 ever amount is entrusted to them is returned a hundred- 
 fold in the results achieved. How many are the re- 
 searches worthy of assistance, and how small are the 
 
 funds available for investigations having no obvious 
 G.D. c 
 
34 DISCOVERY CH. 
 
 practical application, are understood only by men of 
 science themselves. 
 
 It would be a revelation to people endowed with a 
 larger share of worldly riches to be present at a meeting 
 of the Committee of the British Association for the 
 Advancement of Science concerned with the allocation 
 of grants for scientific purposes. Thirty or forty of the 
 leading men of science in the British Isles debate for 
 several hours how to divide the sum of about 1,000 
 which represents the amount available from the sale 
 of tickets at each annual meeting. There are many 
 applications for grants from committees of each of the 
 twelve sections of the Association, and the amount 
 required has usually to be whittled down to 5 or 10, 
 which often does not cover the expense of stationery 
 and postage of a research committee. Not one penny 
 goes into the pockets of the men who are conducting the 
 researches, yet claim after claim has to be passed, or 
 reduced to its lowest limits, because the fund is miserably 
 inadequate to meet the demands made upon it. 
 
 The Royal Society was unable to find the money 
 required to print Newton's Principia a work which 
 will always be regarded as one of the most remarkable 
 products of the human intellect that the world has 
 ever seen and it was published at the expense of his 
 friend Halley. Our scientific societies are in little better 
 position to-day. Their members most of whom possess 
 but very slender means pay by their own subscriptions 
 for the publication of the results of their investigations. 
 They sacrifice their leisure, and draw upon their limited 
 resources, not only that knowledge may be increased, 
 but also that the gain may be published to the world, 
 which is free to make use of it. 
 
 It is difficult for the man of the world to understand 
 
ii TRUTH AND TESTIMONY 35 
 
 the altruistic spirit which induces men of science to band 
 themselves together in societies having for their sole 
 aim the advancement of knowledge in particular direc- 
 tions ; and that these men should themselves pay to 
 enlighten and benefit others by the publication of their 
 researches is almost incomprehensible to the selfish or 
 money-making mind ; yet such is the case. While the 
 State grant made by Great Britain towards the expense 
 of the publications of learned societies is limited to the 
 sum of one thousand pounds annually to the Royal 
 Society, several times this amount is expended each year 
 upon stationery alone used by members of the House of 
 Commons. 
 
 The politicians who pay themselves a salary for the 
 time they devote to party tactics and personal persiflage, 
 would be astounded if the proposal were made to provide 
 for the support of Fellows of the Royal Society or of any 
 other scientific institution, yet of the relative values to 
 the nation of the work done in the two spheres of politics 
 and science, there can be no question. In a splendid 
 building and surrounded with all the appurtenances of 
 precedent and dignity, months and years are wasted 
 in a game of finding weak points in arguments relating 
 to subjects many of which are of doubtful national 
 importance ; while the scientific elect of the country 
 are crowded in modest apartments to discuss discoveries 
 which it has cost them much time and frequently much 
 money to complete, and for the publication of which 
 they must themselves make provision. It requires the 
 satire of a Swift to describe the disparity of support 
 afforded to polemics and natural philosophy by a State 
 that owes most of its modern advance to apostles of 
 scientific truth. 
 
CHAPTER III 
 
 THE SCIENTIFIC MIND 
 
 One use of physical science is that it gives definite ideas. 
 
 Sir Humphry Davy. 
 The man of science has learned to believe in justification, 
 
 not by faith, but by verification. Huxley. 
 The future of our civilisation depends upon the widening 
 
 spread and deepening hold of the scientific habit of 
 
 mind. Prof. John Dewey. 
 Occasionally, and frequently, the exercise of the judgment 
 
 ought to end in absolute reservation. We are not 
 
 infallible, and so we ought to be cautious. Faraday. 
 To the natural philosopher, there is no natural object 
 
 unimportant or trifling. From the least of Nature's 
 
 works he may learn the greatest lessons. Sir John 
 
 Herschel. 
 I do not know anything, except it be humility, so valuable 
 
 in education as accuracy. Direct lies told to the world 
 
 are as dust in the balance when weighed against the 
 
 falsehoods of inaccuracy ; and accuracy can be taught. 
 
 Sir Arthur Helps. 
 Scientific thought does not mean thought about scientific 
 
 subjects with long names. There are no scientific 
 
 subjects. The subject of science is the human universe ; 
 
 that is to say, everything that is, or has been, or may be 
 
 related to man. W. K. Clifford. 
 
 THE main qualities which go to make up a scientific 
 mind are not peculiar attributes of the man of science ; 
 they may be recognised as belonging to men who have 
 
CH. in THE SCIENTIFIC MIND 37 
 
 commanded or deserved success in other departments 
 of intellectual activity. Science, as Huxley said, is 
 organised common sense ; and all men who have been 
 drilled in the ways of common sense should, therefore, 
 possess the characteristics of a fruitful scientific mind 
 as defined by one in whom it was clearly manifest : 
 
 In the first place, above all things, his nature must be one which 
 vibrates in unison with that of which he is in search ; the seeker 
 after truth must himself be truthful, truthful with the truthful- 
 ness of Nature. For the truthfulness of Nature is not wholly the 
 same as that which man sometimes calls truthfulness. It is far 
 more imperious, far more exacting. Man, unscientific man, is 
 often content with "the nearly," and "the almost/' Nature 
 never is ... In the second place, he must be alert of mind. 
 Nature is ever making signs to us, she is ever whispering to us 
 the beginnings of her secrets ; the scientific man must be ever 
 on the watch, ready at once to lay hold of Nature's hint, however 
 small, to listen to her whisper, however low. 
 
 In the third place, scientific inquiry, though it be pre-eminently 
 an intellectual effort, has need of the moral quality of courage 
 not so much the courage which helps a man to face a sudden diffi- 
 culty as the courage of stedfast endurance. Sir Michael Foster. 
 
 Love of truth creates the habit of accuracy and 
 exactness in matters of fact which characterises a 
 scientific mind. Conviction counts for nothing, and any 
 knowledge arrived at as the result of observation or 
 experiment must be capable of being verified by other 
 investigators who will follow the same road. Scientific 
 truth is thus objective and not subjective ; it must be 
 open to all eyes and not a vision limited to the conscious- 
 ness of one mind. The distinction between this kind of 
 truth which we can all examine for ourselves if we wish, 
 and the truth which is a matter of personal conviction, 
 is fundamental. Knowing that others may repeat his 
 observations and that by the confirmation of them or 
 otherwise will he be judged, the student of science learns 
 
38 DISCOVERY CH. 
 
 that faithfulness to fact in every detail is required of 
 him. The habit of mind thus acquired is never willing 
 to base conclusions upon the flimsy evidence which 
 satisfies most people. It is a mill that requires verifiable 
 fact for its grist before it can deliver the good white 
 flour of scientific conclusion into the hopper. This is 
 the mind which a scientific education is intended to 
 produce ; and no substitute of words or symbols for 
 things can give it. 
 
 Advocates of traditional learning cannot understand 
 the educational difference between contact with natural 
 fact and the study of allusions in classical literature. 
 Theirs was the view taken by the old school of thought 
 in the University of Cambridge when a demand was 
 made for funds to build laboratories in the last third of 
 the nineteenth century. Provision of opportunity for 
 the development of an independent observational type of 
 mind was opposed on the ground that it was not good 
 to attach more importance to things seen and done than 
 to things communicated to it by someone in authority. 
 "If," said a leading mathematician of those days, " he 
 does not believe the statement of his teacher probably 
 a clergyman of mature knowledge, recognised ability, 
 and blameless character his suspicion is irrational and 
 manifests a want of power of appreciating evidence." 
 
 Everything depends upon the meaning to be attached 
 to evidence. The only evidence of value in science, and 
 the only testimony which a student of science is com- 
 petent to give, is that derived from his own observations. 
 Hearsay evidence is not admitted in a court of law or 
 given any weight in a scientific discussion, even when the 
 informant is a clergyman of blameless character. A 
 witness is expected to give a truthful account of the facts 
 of a case as they presented themselves to him ; and at the 
 
in THE SCIENTIFIC MIND 39 
 
 tribunal of science he dare not offer false testimony. 
 His observations must be exact if they are to stand 
 the test of cross-examination ; his evidence must be 
 impartial if it is to have any weight ; and his loyalty 
 should be to truth alone, as understood by him, if it is 
 to influence the verdict. 
 
 But the scientific man is a judge as well as a witness ; 
 his own investigations provide him with the evidence 
 upon which he himself passes judgment ; and when he 
 is asked to accept conclusions or subscribe to convictions 
 in support of which no facts are forthcoming, he 
 declines to derogate his reason to his desire. As an 
 example of this attribute of a scientific mind, which 
 asks for evidence when earthly matters or historical 
 records are under consideration, the view taken by 
 Huxley in regard to the former narrow interpretation 
 put upon the Mosaic record of creation is typical. 
 
 I find no difficulty in conceiving that, at some former period, 
 this universe was not in existence ; and that it made its appear- 
 ance in six days (or instantaneously if that be preferred), in 
 consequence of the volition of some pre-existent Being . . . 
 Far be it from me to say that it is untrue because it is impossible. 
 I confine myself to what must be regarded as a modest and 
 reasonable request for some particle of evidence that the existing 
 species of animals and plants did originate in that way, as a 
 condition of my belief in a statement which appears to me to be 
 highly improbable. Huxley. 
 
 How can the mind which is continually working for 
 exact knowledge, and is ready to reject any belief or 
 revise any opinion when shown to be opposed to fact, 
 occupy a different position ? When facts are not avail- 
 able it is equally permissible to believe or to doubt. 
 Nothing is impossible : but in the court of natural 
 knowledge nothing is acceptable without proof. The 
 duty of science is to obtain trustworthy evidence from 
 
40 DISCOVERY CH. 
 
 every available source, and to arrive at conclusions from 
 it. But clear and complete testimony is difficult to 
 obtain even of the events and occurrences of everyday 
 life ; and it can only be elicited from Nature by the mind 
 that hesitates to believe and requires positive impressions 
 in order to be convinced. The man of science, by virtue 
 of his training, is alone capable of realising the difficulties 
 often enormous of obtaining accurate data upon 
 which just judgment may be based. 
 
 It is only the active worker the original investigator who, 
 by personal appeal to Nature through artificially imposed con- 
 ditions, i.e. experiment, or through observation, i.e. ready-made 
 phenomena, has come to understand fully what a fact really 
 means in the scientific sense ; to realise how laborious is the 
 process of wooing truth and how ambiguous are the answers often 
 given by Nature to his cross-examinations. I have elsewhere 
 recorded a humorous rejoinder by Darwin on one of the very 
 few occasions when it was my never-forgotten privilege to have 
 met him ; as this reply bears so closely upon the present topic 
 I will venture to repeat it. I had been dwelling upon this very 
 point of the difficulty of getting Nature to give a definite answer 
 to a simple question, when, with one of those mirthful flashes 
 that occasionally lighted up his features, he retorted, " She will 
 tell you a direct lie if she can." Prof. R. Meldola. 
 
 The great historian, Hume, referring to the inception 
 of the Royal Society, said that it is the part of scientific 
 men to lift the veil from the mysteries of Nature. The 
 only mysteries with which the natural philosopher is 
 concerned are those belonging to the material universe. 
 In untramundane matters conviction takes the place 
 of observation. The poet and the metaphysician feel 
 that certain thoughts are true, and the ideas thus 
 conceived are to them as definite facts as any inferences 
 depending upon the use of the senses. Such feelings 
 do not admit of objective demonstration and cannot, 
 therefore, be measured by the standards of natural or 
 
in THE SCIENTIFIC MIND 41 
 
 physical science. They belong to another world, which 
 the describer of phenomena may contemplate but is 
 usually unqualified to enter. 
 
 It is possible that absolute truth will come by intro- 
 spection rather than by studies of material conditions 
 and things, but this need not discourage the scientific 
 investigator fiom examining the facts of the physical 
 universe and expressing the results as phenomenal 
 knowledge whatever may be the ultimate Reality 
 behind them. We shall not be judged by what we 
 cannot know but by the use we make of the opportunity 
 given us to work and to understand. " If each of us," 
 said Berthollet, " adds something to the common domain 
 in the field of science, of art, of morality, it is because 
 a long series of generations have lived, worked, thought 
 and suffered before us." 
 
 All labour that demands exactness, honest thought 
 and steady application is worth doing, and all these 
 things are required of a worker for science. Each stone 
 chiselled for the temple of science has the mason's mark 
 scribed upon it ; and if it is not fairly and squarely 
 fashioned it will be rejected by the builders. Remem- 
 bering this, the scientific mind cannot be content with 
 the perfunctory performance of any task before it ; the 
 work must be true if it is to stand the judgment of 
 to-morrow as well as to-day ; therefore it is sacred. 
 
 Devotion to science is a tacit worship a tacit recognition of 
 worth in the things studied ; and by implication in their cause. 
 It is not a mere lip-homage, but a homage expressed in actions 
 not a mere professed respect, but a respect proved by the 
 sacrifice of time, thought, and labour. Herbert Spencer. 
 
 The gospel of work is the gospel of science. Go into 
 the fields of Nature and labour if you would become a 
 disciple of science; for not otherwise can the kingdom 
 
42 DISCOVERY CH. 
 
 of natural knowledge be gained. By nothing but 
 patient toil and the quiet thought which it brings can 
 a scientific habit of mind be acquired. No amount of 
 learning from books or of listening to the words of 
 authority can be substituted for the spade-work of 
 investigation. New treasures can never be secured 
 from Nature without effort ; " tribulation, not undis- 
 turbed progress, gives life and soul, and leads to success, 
 when success can be reached, in the struggle for natural 
 knowledge." 
 
 Success in science means the birth of new knowledge. 
 Patient observation and productive thinking are what 
 the world needs for progress, and what true scientific 
 study demands. There are now so many opportunities 
 of obtaining ready-made opinions that the habits of 
 independent thought, caution in accepting assertions, 
 and critical inquiry into evidence, are becoming atrophied 
 by disuse. Vox populi, vox Dei may be a sound demo- 
 cratic principle for political platforms, but it stands for 
 nothing in science. The men who have advanced the 
 human race throughout the ages are those who have 
 stood for individuality as against the conclusions of the 
 crowd. Cultivate appreciation for beauty, the instinct 
 for truth and the creative power, and all the rest shall 
 be given unto you. In Nature 
 
 Beauty is truth, truth beauty ; that is all 
 
 Ye know on earth, and all ye need to know. Keats. 
 
 Truth, Beauty, Learning, Observation, Reason, 
 Expression, Production, are powers which all of us 
 possess in varying degrees ; and the greatest of the seven 
 is Production, whether it be applied to literature, art, 
 or science. 
 
 The all-round liberally-educated man, from Palaeolithic times 
 to the time when the earth shall become a cold cinder, will always 
 
in THE SCIENTIFIC MIND 43 
 
 be the same, namely, the man who follows his standards of truth 
 and beauty, who employs his learning and observation, his 
 reason, his expression, for purposes of production, that is, to 
 add something of his own to the stock of the world's ideas. 
 Prof. H. F. Osborn. 
 
 The power to produce is not the exclusive possession 
 of any particular class ; and in the realm of science it 
 comes to all who will approach Nature with clear eyes, 
 will observe accurately, weigh the observations with 
 unprejudiced mind and weave them into a reasonable 
 web of interpretation. These qualities of a scientific 
 mind come not by believing but by doing ; not from 
 contentment with things as they are but from a desire 
 to know something of the land beyond the hills. 
 
 Natural Science is a subject which a man cannot learn by paying 
 for teachers. He must teach it himself, by patient observation, 
 by patient common sense. And if the poor man is not the rich 
 man's equal in those qualities, it must be his own fault, not his 
 purse's. Charles Kingsley. 
 
 The true meaning of Nature can be understood only 
 by those in direct communion with her. Every devout 
 student has to learn to read the book of Nature for 
 himself; and when he has done so he cannot think 
 lightly of the wonders revealed to him. 
 
 The study of Nature is an intercourse with the highest mind. 
 You should never trifle with Nature. At the lowest her works 
 are the works of the highest powers, the highest something in 
 whatever way we may look at it. A laboratory of Natural 
 History is a sanctuary where nothing profane should be tolerated. 
 I feel less agony at improprieties in churches than in a scientific 
 laboratory. Louis Agassiz. 
 
 At the beginning of his career, Agassiz wrote to his 
 father, " I wish to be a good son, a good citizen, and the 
 first naturalist of my time " ; and his life realised these 
 aims. He was born in a little village in Switzerland in 
 
44 DISCOVERY CH. 
 
 1807, and attained the highest reputation as a naturalist 
 in Europe before he removed to the United States of 
 America when thirty-nine years of age. The nobility 
 of his character, his untiring efforts to increase the 
 knowledge of science, and his inspiring personality, 
 brought him many friends and pupils. An active 
 generation of Nature students was created by his work 
 and influence. His fiftieth birthday was celebrated on 
 May 28, 1857, at a club of distinguished men of which he 
 was a member ; and upon that occasion Longfellow read 
 a memorable poem in which occur the well-known verses: 
 
 And 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. 
 
 The only qualifications required for the study of 
 Nature's story-book are devotion to truth, and sincerity 
 of spirit ; all the other qualities will come to the pos- 
 sessor of these, and a habit of mind will be developed 
 that tries to face all facts squarely and honestly, 
 despises shams and false conventions, and exposes 
 superstition whenever it is encountered. These are 
 the standards of scientific integrity, and the man whose 
 ideals are dominated by them has found the way to 
 intellectual and spiritual salvation. 
 
 Science seems to me to teach in the highest and strongest 
 manner the great truth which is embodied in the Christian 
 
in THE SCIENTIFIC MIND 45 
 
 conception of entire surrender to the will of God. Sit down before 
 fact as a little child, be prepared to give up every pre-conceived 
 notion, follow humbly wherever and to whatsoever abysses 
 Nature leads, or you shall learn nothing. I have only begun to 
 learn content and peace of mind since I have resolved, at all 
 risks, to do this. Huxley. 
 
 Huxley's attitude towards the belief in a future life 
 was at one time the cause of much bitterness against 
 him ; yet it is only another illustration of his reluctance 
 to make a positive assertion about a subject upon which 
 no evidence, or rather evidence which appealed to him, 
 was available. The survival of the soul is beyond the 
 bounds of our terrestrial experience ; and much as 
 Huxley may have wished to believe in it, he could not 
 do so without being false to his personal convictions. 
 His position was beautifully expressed in a pathetic 
 letter which he wrote to Charles Kingsley in 1860, soon 
 after the death of his first child. 
 
 My convictions, positive and negative, on all the matters of 
 which you speak, are of long and slow growth and are firmly 
 rooted. But the great blow which fell upon me seemed to stir 
 them to their foundations, and had I lived a couple of centuries 
 earlier I could have fancied a devil scoffing at me and them 
 and asking me what profit it was to have stripped myself of the 
 hopes and consolations of the mass of mankind ? To which my 
 only reply was and is, " Oh, Devil ! truth is better than much 
 profit. ' ' I have searched over the grounds of my belief, and if 
 wife and child and name and fame were all to be lost to me one 
 after the other as the penalty, still I would not lie. Huxley. 
 
 What matters it if a man who will let such a creed as 
 this control his life does not accept the beliefs of parti- 
 cular sects ? Whether we are Christian or Moham- 
 medan, Buddhist or idolater, there is a heaven awaiting 
 us if we are faithful to the good that is in us. Speaking 
 to Mr. John Fiske on one occasion, Mr. Alexander 
 Macmillan said : "I tell you, there is so much real 
 
46 DISCOVERY OH. 
 
 Christianity in Huxley that if it were parcelled out 
 among all the men, women and children in the British 
 Islands there would be enough to save the soul of every 
 one of them, and plenty to spare." 
 
 The man who lives a moral life merely because he 
 wishes to save his own precious soul is little better than 
 an expectant Hedonist ; for his motive is personal 
 profit. He may be saved from punishment hereafter 
 by being negatively evil, but his life will be of no benefit 
 to the human race unless he is positively good. What 
 existence awaits us across the dark river we cannot 
 say ; but we do know that here on earth each thread 
 of life is intended to contribute to the web designed by 
 its Creator. 
 
 Science may not be able to provide a complete code 
 of ethics, but it does teach that every action carries with 
 it a consequence not in another world but in this 
 to be felt either by ourselves or by others, in our own 
 time or the generations to come. The knowledge that 
 effect inevitably follows cause in Nature makes the 
 student of science circumspect in all his dealings with 
 her. In the sublime words of Francis Thompson : 
 
 All things by immortal power 
 
 Near or far, 
 
 Hiddenly 
 
 To each other linked are, 
 
 That thou canst not stir a flower 
 
 Without troubling of a star. 
 
 The man who keeps this thought constantly before 
 him, and understands the altruistic principle suggested 
 by it, cannot act lightly towards others or himself. 
 But neither this principle nor any other stimulus to 
 high endeavour can have any significance in moral 
 philosophy unless it is put into practice or creates a 
 
in THE SCIENTIFIC MIND 47 
 
 response in the form of action. Light is invisible until 
 it strikes a material body, and a maxim of conduct has 
 likewise no practical meaning until it is reflected in 
 human life. The final test of a gospel is the influence 
 it has upon those who follow it ; and by that test the 
 Spirit of Science is content to be judged. Let one who 
 represented the Christian faith at its highest and best 
 testify to the virtues of men who are faithful students 
 of science : 
 
 Good men, honest men, accurate men, righteous men, patient 
 men, self -restraining men, fair men, modest men. Men who are 
 aware of their own vast ignorance compared with the vast amount 
 that there is to be learned in such a universe as this. Men who 
 are accustomed to look at both sides of a question ; who, instead 
 of making up their minds in haste like bigots and fanatics, wait 
 like wise men, for more facts, and more thought about the facts. 
 In one word, men who have acquired just the habit of mind 
 which the study of Natural Science can give, and must give ; 
 for without it there is no use studying Natural Science ; and 
 the man who has not got that habit of mind, if he meddles with 
 science, will merely become a quack and a charlatan, only fit 
 to get his bread as a spirit-rapper, or an inventor of infallible 
 pills. Charles Kingsley. 
 
 When King George III. appointed Herschel king's 
 astronomer at a salary of 200 a year, Sir William Watson, 
 Herschel's friend at Bath, exclaimed, " Never bought 
 monarch honour so cheaply." But it is so unusual for 
 a royal personage in England to give any practical 
 support to scientific studies that this remark seems a 
 trifle ungenerous, particularly as King George's action 
 enabled Herschel to give up the teaching of music and 
 concentrate his attention upon astronomy, and the 
 construction of telescopes, in aid of which he afterwards 
 obtained two grants of 2,000 each. " I spend money 
 on war because it is necessary," said George III. on ojne 
 occasion to Lalande, who had thanked him for his 
 
48 DISCOVERY CH. 
 
 encouragement of astronomy, " but to spend it on 
 science, that is pleasant to me. This object costs no 
 tears ; it is an honour to humanity." 
 
 The achievements of science represent increase of 
 knowledge not alone for the man who makes it, not 
 alone also for the nation or country to which he belongs, 
 but for the whole human race. Power and glory gained 
 by victory in war carry with them the humiliation 
 and exploitation of the vanquished ; and on both sides 
 human life is sacrificed to causes which are often 
 far from righteous. The conquests of science do not 
 mean the aggrandisement of one country or people at 
 the expense of another, but gifts to all who will receive 
 them. The only domain which it is desired to penetrate 
 is that of ignorance ; and the fight is against the physical 
 and mental death which is its heritage. For light 
 instead of darkness, for truth in the place of error, for 
 the fruit of the tree of knowledge of good and evil, the 
 warriors of science carry on their continuous campaign. 
 Probably no granite block will record their actions or 
 marble monument declare the renown of their leaders, 
 but neither will their spirits be disturbed by the moans 
 of the widow and fatherless which must ever be associated 
 with the victories of military commanders. 
 
 When a new city appeared on Asgard's Hill the abode 
 of the gods of the northern Sagas after the destruction 
 and renewal of the world, a new race of men came to it 
 from Memory's Forest ; and Loki, the disturber of law 
 and order, as well as Fenrir the destroyer, had no place 
 in it. The new race was typical of the scientific spirit 
 which lives for ever, and of those who labour for new 
 knowledge. 
 
 They are the salt of the earth, which keeps the world of man 
 from decaying back into barbarism. They are the children of 
 
Phclo. Henry Dixon & Son. 
 
 II. THE SPIRIT OF THE SUMMIT. 
 Painting by Frederick, Lord Leighton, P.R.A., 
 (1830-1896). 
 
in THE SCIENTIFIC MIND 49 
 
 light. They are the aristocracy of God, into which not many 
 noble, not many rich, not many mighty, are called. Most of 
 them were poor ; many all but unknown in their own time, 
 many died and saw no fruit of their labours ; some were per- 
 secuted, some were slain, as heretics, innovators and corruptors 
 of youth. Of some the very names are forgotten. But though 
 their names be dead, their works live, and grow and spread over 
 ever fresh generations of youth, showing them fresh steps towards 
 that temple of wisdom which is the knowledge of things as they 
 are ; the knowledge of those eternal laws by which God governs 
 the heavens and the earth, things temporal and eternal, physical 
 and spiritual, seen and unseen, from the rise and fall of mighty 
 nations to the growth and death of moss on yonder moors. 
 Charles Kingsley. 
 
 The scientific mind seeks continually for natural 
 revelations whether they can be applied to arts and 
 industries or not. The delight is in the chase, and it 
 ceases with the capture. An Oxford professor once 
 said that the one thing he valued in the system of 
 quaternions was the certainty that it could not be 
 denied by any utilitarian applications. The spirit that 
 prompted this remark was possibly obscurantist, and 
 the prediction has proved to be incorrect, but it 
 reflects the feeling of many scientific investigators, 
 who work primarily to extend knowledge and to 
 learn more of the mysteries of the universe, with little 
 thought of the possible usefulness of their observa- 
 tions and discoveries. To men of this type of mind, 
 science is sacred, and they bow their heads before 
 the vastness of the unknown. Realising that the 
 steps forward are very short in comparison with 
 distance to be traversed by the human race in the 
 future, they confess the truth of the stanza : 
 
 Thou hast not gain'd a real height, 
 Nor art thou nearer to the light, 
 Because the scale is infinite. Tennyson. 
 
50 DISCOVERY OH. 
 
 Humility is indeed a distinctive quality of every 
 scientific mind ; not humility before man and man- 
 made images, but before the marvellous universe in 
 which the Earth is only a particle. By his devotion to 
 Nature, the man of science is exalted above the planes 
 occupied by those who pay no attention to her ; and 
 he is humbled by the greatness of the view presented 
 to him. 
 
 The wisdom of God receives small honour from those vulgar 
 heads that rudely stare about, and with a gross rusticity admire 
 His works ; those highly magnify Him, whose judicious enquiry 
 into His acts, and deliberate research into His creatures, return the 
 duty of a devout and learned admiration. Sir Thomas Browne. 
 
 The holy flame of wisdom burns brightly in a scientific 
 mind and its rays are diffused for the benefit of mankind. 
 The conviction that devotion to the study of Nature 
 exalts the Creator gives courage and power to those who 
 possess it ; it is the Divine afflatus which inspires and 
 enables the highest work in science. Novitiates in the 
 temple of natural knowledge learn from their teachers 
 this cardinal principle of their calling. Hearken to the 
 high note struck by a pioneer of electricity in an address 
 to his students : 
 
 Nothing but the conviction that our love of knowledge is an 
 endeavour after a true reality, and that it is true life and true 
 harmony, can give you a genuine enthusiastic love of wisdom. 
 The conviction that when you diffuse knowledge you are instru- 
 mental in the consolidation of God's Kingdom on earth can alone 
 give you a true and unalloyed desire to lead those around you 
 towards a higher light and higher knowledge. This is the im- 
 portant vocation for which you have begun to educate yourselves. 
 Continue your endeavours with huly seriousness, and you will 
 become capable of participating in a joy which the world cannot 
 bestow, and your works will be a blessing to your father- 
 land ; yes, and will confer a benefit on the whole human race. 
 H. C. Oersted. 
 
in THE SCIENTIFIC MIND 51 
 
 The savage endows his images of wood and stone with 
 divine attributes, and makes them objects of worship, 
 and the Gods of all men and ages reflect the thoughts 
 and aspirations of those who fall down before them. 
 Volney wrote in Les Ruines : " Ce n'est point Dieu qui 
 a fait 1'homme a son image, c'est 1'homme qui a figure 
 Dieu sur la sienne," but long before him Xenophanes 
 had said " Men make gods in their own image," and had 
 held that the representations of the gods in the human 
 form by Homer and Hesiod were directly responsible 
 for the moral corruption of the 'time. The image in 
 which man makes God is determined chiefly by extent of 
 knowledge of the universe ; the shape that satisfies the 
 common mind evokes no spirit of reverence in that 
 which stretches out to the stars or studies the profound 
 marvels of the life of the simplest organism. 
 
 Science alone can give us true conception of ourselves and our 
 relation to the mysteries of existence. Only the sincere man of 
 science and by this title we do not mean the mere calculator 
 of distances, or analyzer of compounds, or labeler of species ; 
 but him who through lower truths seeks higher and eventually 
 the highest only the genuine man of science, we say, can truly 
 know how utterly beyond not only human knowledge but human 
 conception is the universal power of which nature, and life and 
 thought are manifestations. Herbert Spencer. 
 
 The mind that thinks in aeons and sounds the depths 
 of interstellar space cannot be brought within the limits 
 of a narrow religious formulary ; yet it is essentially 
 devout, and it influences for good all with whom it 
 comes in contact. G. F. Watts exerted a remarkable 
 power over others by his elevating personality. On one 
 occasion a lad who was living a fast life owing to the 
 dissolute and vicious company he met at his father's 
 house, walked with Watts across a park in London, on 
 a night when the dome of the sky was brilliant with 
 
52 DISCOVERY CH. 
 
 stars. From that time the life of the lad underwent a 
 change ; and when some years later he was asked what 
 had been said to give him higher aspirations the answer 
 was simply, " We talked of the stars." By the light 
 of the heavens he was able to see the dust in the road 
 he had been treading and to select cleaner paths for 
 his journey towards manhood. 
 
 Whether science is studied for its proximate value or 
 for the sake purely of increased knowledge, it creates 
 a consciousness which transfigures life. Neither it nor 
 philosophy can satisfy the religious instincts of the plain 
 man who requires a personal and social being to worship. 
 But though religion exists without science, there is no 
 science without religion ; and the study of the laws of 
 Nature creates a respect for them and reverence for 
 their Maker of a far profounder kind than the ordinary 
 mind can conceive. 
 
 There cannot be any issue between faith and science, for 
 science and faith mutually exclude one another ; not in the sense 
 that the one renders the other impossible, or vice versa, but rather 
 that so far as science extends faith does not exist, and faith begins 
 where science leaves off. It cannot be denied that beyond this 
 limit there may be real objects to be embraced by faith. It is, 
 therefore, not the object of science to destroy faith, but rather to 
 define the boundaries to which knowledge extends, and within 
 these to establish a uniform system. Rudolf Virchow 
 
 There is, indeed, no conflict between religion and 
 science ; one is the expression of an instinct, the other 
 is a spirit of inquiry into the character and meaning 
 of all things visible and invisible in the universe. 
 " Science is bound," said Lord Kelvin, " by the ever- 
 lasting law of honour, to face fearlessly every problem 
 which can fairly be presented to it." It does not set 
 out to establish or depose any particular articles of 
 belief or substance of faith, but to examine critically 
 
in THE SCIENTIFIC MIND 53 
 
 whatever comes before it in the natural world and to 
 testify faithfully to what is seen. The knowledge thus 
 gained may at times appear to undermine the founda- 
 tions of belief, but that need cause no anxiety, for in 
 the course of years the truth will prevail and error will 
 be confounded, whether it comes from conviction or 
 observation. 
 
 The dogmatism of a few generations ago, both of men 
 of science and theologians, is giving way to a more 
 liberal spirit ; and all who are searching earnestly for 
 truth are considered to be worshippers at the same 
 shrine. But any attempt to express traditional super- 
 naturalism in terms of objective reality, or to bring 
 modern science within the ambit of scriptural exegesis, 
 is to design a flimsy shelter for the destitution of the 
 semi-reasonable. Neither creed nor doctrine shall 
 place boundaries upon the field of inquiry. " Science," 
 said Carl Ernst von Baer, " is, in its source, eternal ; 
 in its operation, not limited by time and space ; in its 
 scope immeasurable ; in its problem, endless ; in its 
 goal, unattainable." The study of science creates this 
 feeling of infinite greatness in all who follow it ; and 
 though it may lead to imperfect interpretations, its 
 motive cannot be irreligious. 
 
 By cherishing as a vital principle an unbounded spirit of 
 inquiry, and ardency of expectation, it unfetters the mind from 
 prejudice of every kind, and leaves it open and free to every 
 impression of a higher nature, which it is susceptible of receiving, 
 guarding only against enthusiasm and self-deception by a habit 
 of strict investigation, but encouraging rather than suppressing 
 everything that can offer a prospect or a hope beyond the present 
 obscure and unsatisfactory state. The character of the true 
 philosopher is to hope all things not impossible, and to believe 
 all things not unreasonable. He who has seen obscurities which 
 appeared impenetrable in physical and mathematical science 
 suddenly dispelled, and the most barren and unpromising fields 
 
54 DISCOVERY OH. 
 
 of inquiry converted, as if by inspiration, into rich and inex- 
 haustible springs of knowledge and power on a simple change of 
 our point of view, or by merely bringing to bear on them some 
 principle which it never occurred before to try, will surely be the 
 very last to acquiesce in any dispiriting prospects of either the 
 present or future destinies of mankind ; while, on the other 
 hand, the boundless views of intellectual and moral, as well as 
 material, relations which open to him on all hands in the course 
 of these pursuits, the knowledge of the trivial place he occupies 
 in the scale of creation, and the sense continually pressed upon 
 him of his own weakness and incapacity to suspend or modify 
 the slightest movement of the vast machinery he sees in action 
 around him, must effectually convince him that humility of 
 pretension, no less than confidence of hope, is what best becomes 
 his character. Sir John Herschel. 
 
 " Blessing, and honour, and glory and power " are 
 not the usual rewards of a life devoted to science. All 
 the benefits of modern civilisation are due to the 
 achievements of science or inventions based upon them ; 
 but neither the multitude nor its masters are familiar 
 with the names of the men whose work has provided 
 the comforts of the present day. If you seek fame and 
 riches, enter not upon a scientific career ; for they are 
 easier won in politics or commerce or many other walks 
 in life. If, however, you will be content with the satis- 
 faction which faithful and unselfish work always brings, 
 Nature offers a rich field in which you can exercise your 
 intellect. 
 
 To qualify for admission into the temple of science it 
 is necessary to offer sacrifices at the altar of know- 
 ledge ; and only those with sincere regard for truth 
 will find their gifts acceptable. Nature must be loved 
 for herself and not for her dowry. The rewards which 
 the world can give may come ; but the discoveries 
 which may bring them can only be secured in the pure 
 quest for the advancement of knowledge. To one alone 
 
in THE SCIENTIFIC MIND 55 
 
 of King Arthur's knights, Sir Galahad, was a complete 
 vision of the Holy Grail vouchsafed ; and he was the 
 single knight that could say : 
 
 My strength is as the strength of ten, 
 Because my heart is pure. Tennyson. 
 
 The secrets of Nature are likewise reserved for those 
 who seek them purely for the love of truth and desire 
 for understanding. The " just and faithful knight " can 
 see Nature unveiled and pass into the spiritual city of 
 science, where purer joys than all earthly fame can give 
 will be his prize. 
 
CHAPTER IV 
 PURSUIT OF KNOWLEDGE 
 
 Knowledge advances by steps, and not by leaps. Macaulay. 
 Prove all things ; holdfast that which is good. St. Paul. 
 We ourselves die, but the fair fame never dies of him who 
 
 has earned it. A Lay of Odin. 
 Knowledge is proud that he has learnt so much ; Wisdom 
 
 is humble that he knows no more. Cowper. 
 When you call a thing mysterious, all that it means is that 
 
 you don't understand it. Lord Kelvin. 
 Where a spring rises, or a river flows, there should we 
 
 build altars and offer sacrifices. Seneca. 
 Knowledge comes by eyes always open and working hands ; 
 
 and there is no knowledge that is not Power. Do 
 
 valiantly, and hope confidently and wait patiently. 
 
 Jeremy Taylor. 
 
 " TAKE this fish," said Agassi z to a student who entered 
 his laboratory to study zoology, " and look at it ; we 
 call it a Haemulon ; by and by I will ask what you 
 have seen." In ten minutes the student thought he 
 had seen all that could be seen in the creature without 
 a magnifying glass, but when he commenced to draw it 
 he discovered new features, and upon the return of 
 Agassiz several hours later he rehearsed what he had 
 observed. " You have not looked very carefully " was 
 the remark of the naturalist, " why, you haven't even 
 seen one of the most conspicuous features of the animal, 
 
CH. iv PURSUIT OF KNOWLEDGE 57 
 
 which is as plainly before your eyes as the fish itself; 
 look again, look again ! " 
 
 For three days the student was kept examining the 
 fish before Agassiz was satisfied that he had discovered 
 for himself the essential points of its structure. On the 
 fourth day, a second fish of the same group was placed 
 beside the first and he was bidden to point out the resem- 
 blances and differences between the two ; another and 
 another followed until the entire family had been 
 examined and the relationships of the members of the 
 group could be brought in review. The student thus 
 received that training in the observation of facts and 
 their orderly arrangement which is characteristic of the 
 scientific method. " Facts are stubborn things," Agassiz 
 would say, " until brought into connection with some 
 general law." 
 
 For successful work in science, or in any subject, the 
 student must have interest as well as the faculty of 
 distinguishing the relative value of things. Confucius, 
 the great Chinese philosopher, used to send away his 
 disciples who did not show sufficient ardour for study, or 
 such as were not sufficiently intelligent to understand 
 him. " When," he said, " I have shown a pupil one 
 corner of the subject, and he is unable to discover the 
 other three, I do not repeat my lesson." Devotion to 
 a subject will lead to the acquisition of knowledge, but 
 mastery is only secured when it is combined with insight. 
 
 The old French anatomist, Mery, said of himself and his 
 colleagues that they were like the rag-pickers of Paris, who knew 
 every street and alley, but had no notion of what went on in the 
 houses. The accumulation of miscellaneous knowledge of useful 
 things, copious, inexact, inapplicable, may, like rag- picking, 
 leave us ignorant of the world in which we live. Let us try to 
 reach the inner life of something, great or small. The truly 
 useful knowledge is mastery. Mastery does not come by listening 
 
58 DISCOVERY Cfi. 
 
 while somebody explains ; it is the reward of effort. Effort, 
 again, is inspired by interest and sense of duty. Interest alone 
 may tire too quickly ; sense of duty alone may grow formal and 
 unintelligent. Mastery comes by attending long to a particular 
 thing by inquiring, by looking hard at things, by handling and 
 doing, by contriving and trying, by forming good habits of work, 
 and especially the habit of distinguishing between the things 
 that signify and those that do not. Prof. L. C. Miall. 
 
 Success or failure at school or college supply no 
 standards by which the promise of the future may be 
 estimated. Originality of thought or achievement is not 
 measurable by the same units as those of absorbing 
 power of a prescribed pabulum, usually tested by a 
 written examination. To be able to reproduce the words 
 of others, or to shuffle mathematical symbols rapidly, 
 may be creditable, but it is not to be compared with the 
 power of originating ideas or devising new solutions to 
 problems. A student may possess many examination 
 certificates and yet be only a kind of text-book gramo- 
 phone. Unless he acquires also the desire to see and do 
 things independently he knows nothing of the scientific 
 spirit which asks for new knowledge gained by individual 
 inquiry. 
 
 The senior wrangler at Cambridge has often been an 
 inferior man, from the point of view of productive 
 mathematical science, than candidates lower on the list, 
 because the examination tested merely the power of 
 writing out the solutions of known classes of problems 
 quickly and precisely. When Lord Kelvin was a student 
 at Cambridge he produced several original papers in the 
 higher branches of mathematics, yet he was beaten in 
 the final examination and was placed second wrangler. 
 The examiners themselves knew his great mathematical 
 abilities, but the examination was a test of memory 
 rather than of originality. Speaking of Kelvin (then 
 
iv PURSUIT OF KNOWLEDGE 59 
 
 named William Thomson), one of the examiners remarked 
 to another, " You and I are just about fit to mend his 
 pens." His genius was recognised, but the examination 
 did not provide a way of showing it. 
 
 To be able to observe details and distinguish minute 
 resemblances and differences are attributes of every 
 scientific observer. In 1781 Sir William Herschel was 
 " searching the skies " when he noticed that one star 
 " appeared visibly larger than the rest." He came to 
 the conclusion, after making several observations, that 
 this object was not a star but a comet. Further studies 
 of the body and its movements proved it to be a new 
 planet the first to be discovered in historic time. The 
 other planets, Mercury, Venus, Mars, Jupiter and Saturn 
 have been known back to the earliest days of the human 
 race of which written records exist ; and the discovery 
 of this new planet, to which the name of Uranus was 
 given, revolving round the sun with the rest, but pre- 
 viously unrecognised, aroused great interest. Other 
 astronomers had examined at various times the parts 
 of the sky occupied by Uranus, but they did not notice 
 any difference of appearance between it and an ordinary 
 star. By overlooking nothing in his field of view, 
 Herschel became the discoverer of a world which proved 
 to be nearly fifty times larger than the globe on which 
 we live. 
 
 Herschel scrutinised everything ; and this all-seeing 
 eye, combined with sagacity of interpretation, is char- 
 acteristic of all great observers. Of Charles Darwin it 
 is recorded : 
 
 He wished to learn as much as possible from an experiment, 
 so that he did not confine himself to observing the single point to 
 which the experiment was directed, and his power of seeing a 
 number of other things was wonderful. There was one quality 
 
60 DISCOVERY CH. 
 
 of mind which seemed to be of special and extreme advantage 
 in leading him to make discoveries. It was the power of never 
 letting exceptions pass unnoticed. 
 
 Writing to Nature of September 29, 1892, Lord Rayleigh 
 said, " I am much puzzled by some recent results as to 
 the density of nitrogen, and shall be obliged if any of your 
 chemical readers can offer suggestions as to the cause. 
 According to two methods of preparation I obtain quite 
 distinct values." It appeared from Lord Rayleigh's 
 observations that while nitrogen derived from the air 
 weighed 2 '3 102 grammes under standard conditions in 
 a certain globe, nitrogen obtained as a chemical product 
 from other sources than the air weighed 2*2990 grammes 
 under exactly the same conditions. These values do 
 not, of course, represent two experiments only, but are 
 averages of many weighings carried out with the greatest 
 possible care and precision. The difference between the 
 two values is 11 milligrammes, or one-half per cent. 
 
 Expressed in British weight, the difference which 
 puzzled Lord Rayleigh was about one-sixth of a grain. 
 Small as this difference was, it exceeded the possible 
 errors of the experiments, and gave rise to the con- 
 clusions that the natural nitrogen from the air was 
 different in character from nitrogen manufactured from 
 chemical substances. Later investigations with Sir 
 William Ramsay led to the discovery of a new gas 
 to which the name Argon was given in air ; and this 
 gas, which is nearly half as dense again as nitrogen, 
 caused the discrepancy noticed by Lord Rayleigh. 
 
 Accurate and minute measurement seems to the non-scientific 
 imagination a less lofty and dignified work than looking for 
 something new. Yet nearly all the grandest discoveries of science 
 have been but the rewards of accurate measurement and patient, 
 long-continued labour in the minute sifting of numerical results. 
 Lord Kelvin. 
 
iv PURSUIT OF KNOWLEDGE 61 
 
 After argon had been isolated from the atmosphere, 
 many sources of nitrogen were examined to see if they 
 also contained the gas mixed with argon or with argon 
 compounds. In the furtherance of this research, Sir 
 William Ramsay was led to experiment upon cleveite 
 a rare Norwegian mineral which had been found to 
 give off, when boiled with weak oil of vitriol, two per 
 cent, of a gas supposed to be nitrogen. The question 
 to be decided was " Did this gas contain any argon, 
 either free or combined ? " ; and the experiments 
 showed that there was only a mere trace of nitrogen in 
 it. To determine readily the character of the remainder, 
 some of it was sealed up in a glass tube, through which 
 an electric discharge was passed this being the usual 
 method of making a gas luminous, so that the quality 
 of its light can be observed by means of the spectroscope. 
 
 The light from the luminous gas from cleveite passed 
 into this marvellous instrument of analysis, and was 
 sifted into its component parts by the glass prism. 
 When the bright lines into which it was resolved were 
 observed, they were found to comprise a number of 
 prominent rays of which the origin was not known ; in 
 other words, the gas which had been believed to be 
 nitrogen was something quite different. One of these 
 rays was especially brilliant ; and it was identified as 
 a line due to helium an element only observed pre- 
 viously in analyses of light from the sun. 
 
 During the total eclipse of the sun in 1868, the spectro- 
 scope showed that the red flames or solar prominences 
 visible here and there around the sun's edge, when the 
 dark body of the moon had cut off the dazzling light of 
 the sun's visible surface, consisted of luminous gases, 
 chief among which was hydrogen. Shortly afterwards 
 Sir Norman Lockyer devised a method of observing 
 
62 DISCOVERY CH. 
 
 solar prominences at any time when the sun is shining ; 
 and he then found that in addition to hydrogen, the 
 light of these tremendous flames commonly exhibited 
 in the spectroscope a line or ray which could not then 
 be matched with light from any terrestrial substance. 
 The enigmatical light appeared to be the exclusive 
 possession of bodies at the intense temperature of the 
 sun ; and for this reason Sir Norman Lockyer gave to 
 the substance emitting it the name helium the element 
 of the sun. It was not until twenty-six years later that 
 helium was isolated by Sir William Ramsay ; so that we 
 have the remarkable fact of an element being actually 
 discovered on the sun long before it was found on the 
 earth. 
 
 Helium is now known to occur in many minerals, 
 and fairly large quantities of the gas are brought 
 annually to the earth's surface dissolved in the waters 
 of deep-seated mineral springs, like those at Bath, being 
 produced in all probability by the disintegration of that 
 wonderful element radium. The minute differences 
 between the weights of atmospheric and chemical 
 nitrogen observed by Lord Rayleigh in 1892 are thus 
 seen to be connected, link by link, with the marvellous 
 properties of radioactive minerals. 
 
 The diligence and persistence shown by men of 
 science in the pursuit of knowledge are as remarkable 
 as acuteness of vision and quickness of understanding. 
 When Herschel was constructing the great mirror for 
 his telescope, he had to do all his polishing by hand, 
 and he found when once the final stage had begun, it 
 was necessary that it should never stop even for a 
 moment. His sister, Caroline, relates how she was 
 kept busy in attending on her brother when polishing : 
 " Since by way of keeping him alive I was constantly 
 
iv PURSUIT OF KNOWLEDGE 63 
 
 obliged to feed him by putting the victuals by bits into 
 his mouth. This was once the case, when, in order to 
 finish a 7 ft. mirror, he had not taken his hand from it 
 for sixteen hours together." 
 
 Herschel undertook the stupendous task of surveying 
 with his telescope the whole of the heavens visible from 
 his observatory. With his instrument the field of view 
 visible at one setting was about one-quarter the apparent 
 size of the full moon, and Herschel had to observe more 
 than 300,000 of such fields in order to make his census 
 of the stars in a hemisphere of space. The method of 
 observation is described by Von Magellen in a letter 
 to Bode, from which the following are extracts : 
 
 He has his 20 ft. Newtonian telescope in the open air. It is 
 moved by an assistant who stands below it ; near the instrument 
 is a clock. In the room near it sits Herschel' s sister, and she has 
 Flamsteed's Atlas open before her. As he gives her the word, 
 she writes down the declination and right ascension. In this 
 way Herschel examines the whole sky ; he is sure that after four 
 or five years (from 1788) he will have passed in review every 
 object above our horizon. Each sweep covers 2 deg. 15 min. in 
 declination, and he lets each star pass at least three times through 
 the field of the telescope, so that it is impossible that anything 
 can escape him. Herschel observes the whole night through; 
 for some years he has observed every hour when the weather 
 is clear, and this always in the open air. 
 
 Another astronomer whose diligence in observation 
 was astonishing was S. H. Schwabe, a native of Dessau, 
 who began to observe the sun in 1826, with the idea that 
 the labour " might be rewarded by the discovery of a 
 planet interior to Mercury," and was led to inquire into 
 the rotation of the sun as indicated by the spots which 
 appear from time to time. Each spot was noted and 
 numbered in the order of its appearance, and when this 
 system of registration had been carried on to the end 
 of 1843, Schwabe modestly remarked that the number 
 
64 DISCOVERY OH. 
 
 of spots visible upon the sun varied periodically, waxing 
 and waning in what seemed to him to be a period of about 
 ten years. But the subject attracted little attention, 
 and it was not until 1851 that astronomers realised its 
 importance. In 1857 the gold medal of the Royal 
 Astronomical Society was presented to the indefatigable 
 observer of Dessau. 
 
 "Twelve years," remarked the President of the Society in 
 his address, " he spent to satisfy himself, six more years to 
 satisfy, and still thirteen more to convince mankind. For thirty 
 years never has the sun exhibited his disc above the horizon of 
 Dessau without being confronted by Schwabe's imperturbable 
 telescope, and that appears to have happened on an average 
 about 300 days a year. So, supposing that he observed but once 
 a day, he has made 9,000 observations, in the course of which he 
 discovered about 4,700 groups. This is, I believe, an instance of 
 devoted persistence (if the word were not equivocal, I should 
 say pertinacity) unsurpassed in the annals of astronomy. The 
 energy of one man has revealed a phenomenon that has eluded 
 even the suspicion of astronomers for 200 years ! . . . I can con- 
 ceive few more unpromising subjects from which to extract a 
 definite result than were the solar spots when Schwabe first 
 attacked them." 
 
 r Everyone can add something to knowledge if he will 
 make use of the opportunities richly offered by Nature. 
 He is a bad workman who grumbles at his tools, and the 
 student of science who neglects research because he 
 does not possess apparatus ready-made and varnished 
 by the instrument-maker, lacks the spirit of the investi- 
 gator. Test the efficiency of the things at your disposal 
 is good advice ; for the knowledge and experience 
 gained by direct communion with Nature, even through 
 the roughest apparatus, is a very valuable educational 
 training. Tradition says that a foreign savant, who 
 had heard of the fame of Dr. Wollaston, the great 
 chemist and physicist who was President of the Royal 
 
iv PURSUIT OF KNOWLEDGE 65 
 
 Society in 1820, called upon him one day and asked to 
 see his laboratory. " Certainly," said Wollaston, and 
 rang the bell. " John," he said to the attendant who 
 entered, " bring up my laboratory." Whereupon John 
 went out and returned in a few moments with all 
 Wollaston's apparatus on a tea-tray. 
 
 Prof. E. C. Pickering, director of the Harvard College 
 Observatory, says that people used to ask if the Obser- 
 vatory possessed the largest telescope in the world. 
 He would answer, " No, but we have the smallest that 
 is doing useful work." The instrument to which he 
 referred was constructed for measuring the light of the 
 bright stars ; and its object-glass was only two inches 
 in diameter. With this, during the years 1880-1882, a 
 hundred thousand measures were made of four thousand 
 stars, mainly visible to the naked eye. Similar instru- 
 ments have since been constructed with larger lenses 
 capable of bringing fainter stars into view, but through- 
 out the work for which Harvard College Observatory 
 is famous in the astronomical world, the principle has 
 been to obtain the maximum efficiency from the instru- 
 ments available. 
 
 This plan of making the best use of whatever is at 
 hand must always be followed if scientific work is to be 
 done. While the dreamer sighs for opportunities, the 
 inquirer works with things as he finds them. Difficulties 
 to the man of science engaged in research are only pro- 
 blems to be solved ; they may hinder progress but never 
 prevent it entirely. " The way I get over a difficulty," 
 remarked an Irishman, "is to go round it " ; and that 
 represents the frame of mind by which advance is made 
 in every branch of human activity. 
 
 For certain scientific purposes " gratings " are required 
 on which about a hundred thousand parallel lines have 
 
66 DISCOVERY CH. 
 
 to be ruled within the width of an inch. All the parts 
 of the machine by which a surface as hard as steel has 
 thus traced upon it, by means of a diamond, a furrow 
 several miles long, have to be made with extreme 
 accuracy. A screw to rule a " grating " six inches 
 wide required two years or more to make ; and almost 
 ten years were occupied in making one to rule a " grat- 
 ing " fifteen inches wide. From beginning to end the 
 process of producing a perfect optical grating is beset 
 with difficulties, and only an indomitable spirit can 
 overcome them. Nothing must be left to chance ; 
 and the slightest disregard of a possible disturbing 
 influence during the grinding of the screw or the ruling 
 of the grating means that months or years of work will be 
 completely wasted. 
 
 Prof. A. A. Michelson, who devoted many years to 
 the perfection of a machine for producing accurate 
 optical gratings, has compared it to an antagonist who 
 was always ready to take advantage of a mistake, yet 
 always played fair. 
 
 One comes to regard the machine as having a personality 
 I had almost said a feminine personality requiring humouring, 
 coaxing, cajoling, even threatening ! But finally one realises 
 that the personality is that of an alert and skilful player in an 
 intricate but fascinating game who will take immediate advantage 
 of the mistakes of his opponent, who " springs " the most dis- 
 concerting surprises, who never leaves any result to chance, but 
 who nevertheless plays fair, in strict accordance with the rules 
 of the game. These rules he knows, and makes no allowance if 
 you do not. When you learn them, and play accordingly, the 
 game progresses as it should. Prof. A. A. Michelson. 
 
 In order to test certain conclusions he had reached 
 as to the effect of the earth's atmosphere in absorbing 
 particular rays of sunlight, a French astronomer, Dr. 
 Jules Janssen, wished to make observations at the 
 
iv PURSUIT OF KNOWLEDGE 67 
 
 summits of high mountains, where the layer of air 
 interposed between him and the sun would be less than 
 at lower levels. He was lame, but that did not prevent 
 him from attaining his object ; he first ascended the 
 Faulhorn, then the Pic du Midi, and afterwards under- 
 took several ascents of Mont Blanc. His lameness 
 made mountain climbing particularly difficult, and in 
 order to reach the summit of Mont Blanc he had to be 
 carried either on a litter or on a sledge. He not only 
 achieved his original purpose, but created the obser- 
 vatory which now stands upon the snow of the very 
 top of this famous peak of the Alps. The observatory 
 is a monument to his energy and tenacity of purpose. 
 Referring to the realisation of the project, he once said, 
 " I have always thought that there are very few diffi- 
 culties which cannot be surmounted by a will strong 
 enough or by study sufficiently profound." 
 
 When Newton was actively engaged in completing 
 one of his important works, a lighted candle which he 
 left in his room burned down, setting fire to papers 
 which represented the results of much labour, and 
 destroyed them. The story of the fire having been 
 caused by a little dog called " Diamond " upsetting the 
 candle, and that the papers related to the famous 
 Principia, is shown by Brewster to be fabulous. The 
 fire did, however, destroy twenty years' work upon 
 light' and colour, which Newton had almost brought to 
 a conclusion, and it was said at the time by a student at 
 Cambridge, where Newton was a Fellow of Trinity 
 College, " everyone thought he would have run mad, 
 when he had seen what was done ; he was so troubled 
 thereat that he was not himself for a month after." 
 All that Newton himself said of the loss thus caused, 
 when asked about it by a friend, was that he was obliged 
 
68 DISCOVERY CH. 
 
 to work the calculations all over again. To have to 
 reconstruct an intricate work from the very beginning 
 was sufficient to appal the strongest mind, but he set 
 about the task and accomplished it. 
 
 The man who has the spirit of science in him is ever 
 ready to sacrifice personal comfort or convenience to it. 
 It is told of Dr. Robert Grant, who was professor of 
 zoology in University College, London, and devoted to 
 his subject, that he spent eight or ten hours of a sleety 
 day in February wading in the shallows of the Firth of 
 Forth, in order to secure some specimens of a certain 
 small aquatic creature which can best be studied in a 
 living state, as its beautiful and varied colours disappear 
 when the animal is dead and immersed in spirit. When 
 showing to his class the specimens he had obtained he 
 said : "I had no companion, I had nothing to eat or 
 drink, I was wet through, my hands were half frozen, 
 and I was chilled to the marrow ; but, gentlemen, I was 
 amply rewarded ; I became the happy possessor of no 
 less than three of these beautiful little creatures, these 
 Dorises," and he held up a phial containing three 
 scarcely visible little bladder-like animals. 
 
 If there is one branch of science more than another 
 in which the infinite patience of genius is required, it is 
 that of the study of insects ; not of insects pinned in 
 boxes or arranged in cabinets, but of the living creatures, 
 with the view of discovering something of their life- 
 history or of understanding a type of mental life on lines 
 different from ours. It is much more exciting to catch 
 insects and to kill them with cyanide or chloroform, so 
 as to convert them into specimens for a collection, than 
 it is to watch their individual characteristics as living 
 things, unravel the complicated thread of changes they 
 undergo, and observe their domestic economy. On this 
 
iv PURSUIT OF KNOWLEDGE 69 
 
 account there are many insect-hunters and collectors, 
 but few who have an intimate acquaintance with the 
 habits of insects in the life. 
 
 One such open-eyed naturalist was Reaumur, born at 
 La Rochelle in 1683, and as diligent and accurate an 
 observer as ever lived. Reaumur's History of Insects 
 occupies six large volumes, and though issued so long 
 ago as between 1734 and 1742 they are still a rich mine 
 of information upon all aspects of insect-life observable 
 with the naked eye or a simple lens. Referring to his 
 accounts of the change from a caterpillar into a chrysalis, 
 and of the chrysalis into a moth, Prof. L. C. Miall says : 
 " These luminous descriptions are now reproduced with 
 cruel abridgment in all popular works which treat of 
 insect-transformations . . . The only important additions 
 which naturalists have made to Reaumur's account 
 of the transformations of Lepidoptera relate to the 
 internal changes, and these demand a minute acquaint- 
 ance with insect anatomy." 
 
 The geometrical or mechanical properties of Nature 
 are far more easily defined with precision than are any 
 of the processes of organic life. Five hundred years 
 before the commencement of the Christian era, Pytha- 
 goras observed that the three angles of every plane 
 triangle together make up two right-angles ; and this 
 conclusion stands now as it did then. Two and a half 
 centuries later Archimedes proved that an object 
 immersed in a fluid is buoyed up with a force equal to 
 the weight of the fluid displaced ; and this principle 
 admits of no alteration whether it is applied to the 
 flotation of a ship in water or the buoyancy of a balloon 
 in air. Hipparchus, the founder of astronomical science, 
 who lived in the second century B.C., determined the 
 periods of revolutions of the planets with remarkable 
 
70 DISCOVERY CH. 
 
 accuracy, and his values differ very slightly from 
 those accepted at the present day. but it was not 
 until eighteen hundred years later that Newton dis- 
 covered the law of gravitation by which the movements 
 of these and other bodies in the solar system are 
 governed. 
 
 An accurate observation remains unaltered throughout 
 the ages. Its scientific value is determined by its truth 
 to Nature ; and the more complete the testimony, the 
 less room is there for elaboration by investigators in 
 succeeding generations. Whatever precise knowledge 
 exists of natural things and operations has been obtained 
 by patient labour. It is so much easier to accept 
 traditional views upon the structure, habits and functions 
 of the various forms of life around us than it is to inquire 
 minutely into them by personal observation that mis- 
 taken ideas often pass currency for hundreds of years 
 before they are detected. Aristotle in his natural 
 history makes a king-bee the governor of a hive, and 
 this view is reflected in Shakespeare's lines : 
 
 For so work the honey-bees, 
 Creatures that by a rule in nature teach 
 The act of order to a peopled kingdom, 
 They have a king and officers of sorts ; 
 
 King Henry V. I. ii. 
 
 It was a country parson, Charles Butler, who, in the 
 early years of the seventeenth century, took the trouble 
 to study bees themselves instead of reading books about 
 them ; and he found that the queen-bee was the dominant 
 factor in the hive community. Milton possibly knew 
 of Butler's work when he wrote in Paradise Lost, 
 published half a century later, of " The female bee, 
 that feeds her husband drone Deliciously, and builds 
 her waxen cells With honey stored." 
 
iv PURSUIT OF KNOWLEDGE 71 
 
 J. J. Swammerdam, son of an apothecary at Amster- 
 dam, carried the investigation of the hive-bee much 
 further than any naturalist before him, though he did 
 not exhaust it. He proved definitely that the so-called 
 " king of the bees " was really a queen and the only 
 effective female in a hive. The chief part of his work 
 was done in 1673, when the dykes were cut to save 
 Amsterdam from the French invasion, so that the hives 
 in Holland were ruined, and scarcely any queens could 
 be procured. Swammerdam spent many months upon 
 the investigation of bees, and took scrupulous pains in 
 examining their structure and habits. Referring to his 
 Biblia Natura, in which the hive-bee is described, Prof. 
 Miall 
 
 The life-history, the anatomy of the male, female and neuter 
 bees in every stage, and the whole economy of the hive, are 
 carefully described . . . The engraved figures would do 
 credit to the most skilful anatomists of any age. This, the first 
 extensive and truly scientific memoir on the hive and its inhabi- 
 tants, carries the exploration a long way at a single bound, and 
 biology can hardly produce a second example of a research 
 so comprehensive and disfigured by so few faults. 
 
 Reaumur extended the knowledge of the honey- 
 bee still further by studies of the living insect in 
 observation hives ; Schirach, in 1771, proved that 
 worker-bees are imperfect females, and the history of 
 the wedding-night was first correctly described by 
 Huber in 1814. Finally, Dzierzon, in the middle of the 
 nineteenth century, showed that the eggs laid by 
 unwedded queens give birth to drones ; that the fertilisa- 
 tion of the queen takes place within a few days of her 
 quitting her cell, and lasts for life ; and that female 
 bees (queens and workers) proceed only from eggs 
 fertilised by drones. Queens and workers are respec- 
 tively produced from female bees by being fed on different 
 
72 DISCOVERY CH. 
 
 foods while in their larval state. The future queen is 
 fed on " chyle food " by the nurses until it assumes 
 the chrysalis change, from which it emerges a perfect 
 female. The future worker is weaned upon the 
 fourth day, and fed henceforth on honey and digested 
 pollen, with the result that it remains an undeveloped 
 female. 
 
 This wonderful history of the hive-bee represents the 
 results of work done by naturalists of many countries 
 and at different times. There have been hundreds of 
 practical bee keepers from ancient to modern times, 
 but they have contributed almost nothing to this know- 
 ledge of the structure and functions of the complicated 
 social community of a hive ; and for the actual fact we 
 have to go to Butler, Bonnet, Swammerdam, Reaumur, 
 Huber, Dzierzon, and other inquiring naturalists whose 
 names are unfamiliar not only to general readers but 
 also to a large part of the scientific world. 
 
 Three hundred years ago little was known of the 
 transformation which insects undergo from the egg to 
 the fly emerging from the larval skin. Harvey, the 
 discoverer of the circulation of the blood, was so far 
 mistaken as to teach that insects were generated by 
 chance, and that the change from a pupa to the winged 
 form was a transmutation like that of a base metal into 
 gold, or the flying nymph of Ovid into a laurel tree. He 
 regarded the pupa as an egg ; and even now the pupae 
 of ants are popularly called ants' " eggs." Swammer- 
 dam persistently pointed out the errors of this belief, 
 and by his studies disposed of it completely. He proved 
 that all the parts of an insect are beneath the larval 
 skin long before the insect emerges ; that, in fact, the 
 larva or pupa is not transmuted into a butterfly but is 
 the butterfly itself in another form. 
 
iv PURSUIT OF KNOWLEDGE 73 
 
 By his laborious studies in the latter half of the seven- 
 teenth century, Swammerdam worked out the complete 
 transformation of insects, and recognised the chief types 
 of development. For his facts he went direct to Nature, 
 and he was rarely deceived by her. Upon most of the 
 subjects studied by him, philosophers and other school- 
 men had been content to pass on fantastic ideas without 
 inquiry into their veracity. Aristotle, Vergil, Pliny and 
 other early writers, all agreed that certain bees, which 
 may sometimes be seen carrying small stones as they 
 fly, do so to prevent being blown out of their course in 
 windy weather. The conclusion was childish, but it 
 was sufficient for writers who had not watched the habits 
 of this insect the mason-bee. When actual observa- 
 tion was made by Swammerdam, nearly two thousand 
 years later, he found that the stones were used by the 
 bee to strengthen its hive. 
 
 Aphids, or plant-lice, are familiar to every gardener, 
 yet how few know anything of their life-history or of 
 the patient work of investigators who revealed it. When, 
 toward the end of the seventeenth century, the ever- 
 curious naturalist, Antony Van Leeuwenhoek, began to 
 study the insects, he sought for their eggs, but without 
 success. Later, he made the surprising discovery that 
 aphids brought forth their young alive, and upon opening 
 an aphis only a fortnight old he found no fewer than 
 sixty young ones in it. Reaumur extended Leeuwen- 
 hoek's observations, and showed that both the winged 
 and wingless aphids could produce living young. He 
 tried to isolate aphids from birth to see if they would 
 still continue to increase their kind, but was prevented 
 by accidents from concluding his observations. When, 
 therefore, Charles Bonnet (1720-1793) asked him to 
 suggest a subject of investigation, the unfinished 
 
74 DISCOVERY CH. 
 
 experiment was proposed as one likely to lead to 
 interesting results. Bonnet was only twenty years of 
 age when he undertook this task. 
 
 He filled a flower-pot with earth, and plunged it into a phial 
 of water, intended to supply the food-plant. A new-born aphis, 
 whose birth had been observed, was placed on the plant, and 
 all was covered up by a bell-jar, which was pressed into the 
 earth, so as to exclude other insects. An aphis found upon the 
 spindle-tree was selected for the first trial, which began on 
 May 20, 1740. Bonnet kept an exact diary of his observations, 
 which were made hourly or oftener during the day; a good 
 lens was continually employed. The aphis changed its skin 
 four times, and came to maturity on June 1, when the first 
 young one was born. By June 21, the unfertilised female 
 had produced 95 aphids, all born alive. Prof. L. C. Miall. 
 
 A similar result was obtained the next year, when 
 two new-born aphids, isolated in the same way, produced 
 respectively 90 and 49 young. Five successive genera- 
 tions of aphids were then bred without the participation 
 of a male insect, and the result, which was contrary to 
 all that was then known of reproduction in nature, was 
 received with lively interest not unmixed with incredulity. 
 The life-history of these insects differs indeed from all 
 pre-conceived ideas. Bonnet's observations established 
 it to be as follows : both winged and wingless aphids pro- 
 duce young alive while food is plentiful, but as the winter 
 approaches this mode of reproduction ceases ; small 
 winged males then appear, and the females lay fertilised 
 eggs from which young aphids emerge in the following 
 spring. Aphids are thus born without the participation 
 of the male insect during mild weather, and their race 
 is carried on from one year to another by the eggs laid 
 by fertile females near the end of the season. 
 
 The discovery of this intricate course of events is far 
 more wonderful than the achievement of any Arsene 
 
iv PURSUIT OF KNOWLEDGE 75 
 
 Lupin or Sherlock Holmes of fiction. There are winged 
 and wingless females both producing live young without 
 any eggs or the intervention of the male, winged insects 
 which produce no young, and eggs from which young 
 emerge ; and the problem was to find the clue which 
 connected these various threads into a skein of evidence. 
 Leeuwenhoek, Reaumur and Bonnet were the chief 
 detectives in this case, and their work, though unknown 
 to the world at large, claims the admiration of all who 
 will consider it. 
 
 The mantle of the French naturalist, Reaumur, fell 
 upon J. H. Fabre, and in these two faithful observers 
 France can claim possession of the greatest students 
 of insect-life the world has ever seen. Fabre, born in 
 poverty and earning for himself and family a salary of 
 64 a year as a schoolmaster, " less," as he says, " than 
 a groom in a well-to-do household," produced works 
 on the habits of insects which stand by themselves, 
 whether we consider them as science or literature. So 
 long ago as 1871, Darwin, in his Descent of Man, referred 
 to Fabre as " that inimitable observer," and Maurice 
 Maeterlinck has happily named him " The Insects' 
 Homer." In his Souvenirs Entomologiques, Fabre re- 
 corded in ten volumes the results of fifty years of 
 observation, study and experiment on living insects of 
 the South of France. 
 
 In 1843, when eighteen years of age, Fabre, with his 
 teacher's certificate, was appointed to take charge of a 
 primary school at Carpentras, at a salary of 28 a year. 
 He there met for the first time the black mason-bee 
 which makes nests of clay on pebbles or a wall and fills 
 them with honey. Reaumur dedicated one of his 
 studies to this interesting insect, but Fabre did not then 
 know of it. He spent a month's salary in the purchase 
 
76 DISCOVERY CH. 
 
 of a standard work on insects, and thus provided food 
 for the mind at the expense of food for the body. " That 
 which I bestowed on the one I retrenched from the 
 other a balance of accounts to which whoever takes 
 science for a livelihood must needs resign himself." 
 Fabre devoured the book, and the delight he derived 
 from it was a compensation for the parsimony he had 
 to exercise to obtain it. " There I learned," he says, 
 " the name of my black bee, and there I read for the 
 first time details of the habits of insects, and found, 
 with what seemed to my eyes an aureole round them, 
 the venerated names of Reaumur, Huber, Leon Dufour ; 
 and while I turned the pages for the hundredth time, a 
 voice whispered vaguely, ' Thou too shalt be a historian 
 of animals.' ' 
 
 The entomological studies thus started, and further 
 excited by reading a pamphlet by Dufour upon the 
 habits of a wasp-like insect, a species of Cerceris, which 
 feeds its progeny upon certain kinds of beetles, were 
 continued by Fabre with unabated enthusiasm and 
 conspicuous success. With supreme contempt for riches 
 and remarkable indifference to worldly honours, in his 
 lifetime he built up a more solid and durable monument 
 than was ever made by hands. His stories of insects 
 are full of dramatic situations and romantic interest. 
 
 As a naturalist he sacrificed everything to his work 
 and gained a knowledge of insect life unequalled by 
 any other observer ; as a writer he possessed a style 
 that enabled him to disclose convincingly to others the 
 scenes enacted before his eyes and commanded the admir- 
 ation of masters of literature. In an age of haste and 
 money-making, when few will devote time to studies 
 which offer little prospect of direct or indirect reward, 
 Fabre quietly continued his observations of Nature's 
 
iv PURSUIT OF KNOWLEDGE 77 
 
 ways with the sole object of becoming intimately 
 acquainted with them. So long as the world shall last 
 his works will be an inspiration to naturalists, and an 
 exemplar of what can be accomplished by the observer, 
 however limited his worldly means may be, who seeks 
 for knowledge in the spirit of humility and truth. 
 
 Most people are now familiar with fossil shells and 
 similar remains found imbedded in many rocks. Such 
 objects were known in very early times, and some 
 philosophers notably Leonardo da Vinci and Bernard 
 Palissy realised that they were the relics of life that 
 once existed at the places where the fossils were found. 
 It was generally believed, however, that marine shells 
 found inland were deposited there by the Deluge ; and 
 that strange animal remains were " freaks of Nature " 
 unworthy of serious study. An English land-surveyor, 
 William Smith, was the first to show, toward the end 
 of the eighteenth century, that fossils provide the key 
 by which the relative ages of the beds of rock which 
 make up the earth's crust can be determined. 
 
 Before Smith commenced his work, fossils were sup- 
 posed to be scattered in haphazard fashion in the rocks. 
 As the result of many years spent in examining rocks 
 in all parts of the country, and collecting the fossils from 
 them, he was able to conclude that each stratum has its 
 own particular fossil population, and that the strata 
 lie upon one another in a regular order. Fossils were 
 thus shown to be the trade-marks of the rock-layers in 
 which they occur. This conclusion enabled a natural 
 system of classification of strata to be introduced, and 
 was the foundation of scientific geology. 
 
 Rocks can be classified according to their appearance 
 or structure, but these features give no information as 
 to the period of the earth's history at which' the rocks 
 
78 DISCOVERY CH. 
 
 were formed. The only trustworthy test of geological 
 age is that afforded by fossil remains, and this principle, 
 established by William Smith, is now used by all 
 geologists as a guide to the order in which deposits 
 were laid down in any part of the earth. The oldest 
 rocks in Great Britain are those in the west ; and as 
 we pass eastward, we traverse beds of rock formed in 
 successive epochs of the earth's history until we come 
 to the relatively recent formations of Essex and other 
 parts of the east coast. Relics of elementary forms of 
 life are found in the older rocks and are succeeded in 
 regular order by remains of fishes, amphibians, reptiles, 
 birds and mammals, until at last deposits are reached 
 containing human remains and evidence of man's 
 handiwork. 
 
 Though the biological significance of this development 
 of life from the simple coral to the complex structure of 
 man was not realised by Smith, it was he who gave the 
 first complete proof that there was a regular succession 
 of forms of life in the beds of the earth's crust. " To 
 effect his object," said Sir Andrew Ramsay, " Smith 
 traced the English formations from end to end of the 
 country with unwearied devotion, and at length, in 
 1815, produced his great geological map of England. 
 He struggled long, almost unrecognised in his labours, 
 but when they were well-nigh at an end, men began by 
 degrees to realise that a master was among them." 
 
 The insight which a naturalist can acquire into the 
 forms of life of the past, by studies of the records of 
 the rocks, is well illustrated by an episode in the life 
 of Louis Agassiz. At a meeting of geologists in England, 
 Agassiz was once asked what kind of fish would be 
 found in fossil form in a particular stratum of the 
 earth's crust. He thought for a moment and then 
 
iv PURSUIT OF KNOWLEDGE 79 
 
 made a sketch of the fish which he believed would live 
 at the time this geological stratum was formed. He did 
 not understand the cheer with which his drawing was 
 received by the company, until someone brought forward 
 an actual fossil specimen which had just been found and 
 showed that it agreed perfectly with the sketch which 
 Agassiz had created from his own knowledge of what 
 characteristics a fish belonging to a particular stratum 
 ought to possess. 
 
 Facts known to everyone often have to wait hundreds 
 of years before their true significance is understood. A 
 remarkable instance of this is the relation of the flower 
 of a plant to the fruit which follows it. In very early 
 days men must have noticed that when the blossom on 
 a tree or bush was destroyed no fruit could be expected 
 from it. First the flower, then the fruit, has been a 
 matter of common knowledge from time immemorial, 
 yet the causal relationship between the two stages was 
 not established until the seventeenth century. Hero- 
 dotus, in the middle of the fifth century B.C., had 
 observed that in Assyria the female tree of the date- 
 palm was made fertile by dusting it with the branches 
 of the male, but he did not pursue his inquiries any 
 further. Other Greek philosophers who followed him 
 taught that fertilisation is unnecessary, that both male 
 and female date-palms bear fruit, and held like beliefs 
 which a single experiment would have shown to be 
 erroneous. So it was with other plants ; nothing was 
 accurately known of the functions of the various parts 
 of the flower concerned in the production of the fruit, 
 and no serious attempt had been made to secure precise 
 knowledge. 
 
 If a common apple blossom be examined, slender 
 filaments or stamens will be seen bearing golden pollen 
 
80 DISCOVERY CH. 
 
 on the anthers at their tops. This pollen is the fertilising 
 element of the plant, and without it no fruit can be 
 formed. It is carried to the sticky stigmas of other 
 apple blossoms by wind or insects, and then starts 
 changes which result in fruit and seed. The anthers 
 are, in fact, the male organs of flowering plants, and the 
 dust they shed is the quickening influence by which a 
 new generation is produced. In some plants such, for 
 example, as the date-palm, mulberry-tree, and willow, 
 the male and female organs are borne on different trees, 
 but in most cases the flower contains both stamens 
 bearing the pollen on their anthers, and stigmas to which 
 the pollen adheres. 
 
 No plant can ripen its fruit unless pollen is supplied 
 to the female organs. The pollen may come from the 
 male organs of the same flower, be borne by wind or 
 insects from another flower of the same species, or be 
 supplied artificially, but in any case it is essential to 
 fertilisation. This was suspected long before anyone 
 made the crucial experiment of isolating a female plant 
 from the pollen of the male in order to test whether 
 fruit bearing the seeds of another generation would 
 then be produced. 
 
 Prof. L. C. Miall describes, in his Early Naturalists, 
 the conclusive observations and experiments by which 
 the doctrine of the sexuality of plants was established 
 by Prof. R. J. Camerarius, professor of botany at 
 Tubingen, toward the end of the seventeenth century. 
 Experiments were first made with the Annual Mercury, 
 in which the sexes are usually represented by different 
 plants, one of which carries the fertilising element 
 while the other bears the fruit and seeds. Two female 
 plants, when isolated, were found to produce only 
 abortive or unfertile seeds ; and, in like manner, when 
 
iv PURSUIT OF KNOWLEDGE 81 
 
 the parts of the flower of maize which receive pollen 
 were cut away, the cobs which afterwards appeared were 
 found to be devoid of seed. 
 
 By these and other experiments Camerarius converted 
 into scientific truth the conjectures as to sexes of plants 
 held by gardeners and botanists almost from the days of 
 the Garden of Eden. Science had to wait, however, 
 nearly one hundred and fifty years longer before the 
 mechanism of fertilisation was completely analysed. 
 It was Dr. Robert Brown who showed in the first half 
 of the nineteenth century that when pollen grains reach 
 the stigma of a plant they send out tubes which pene- 
 trate openings in the outer skin of rudimentary seeds 
 and set up the changes that result in the formation of 
 seeds or embryos. 
 
 It is to the credit of science that many notable 
 advances have been made by men who have not been 
 professionally occupied with scientific work, but have 
 devoted their leisure hours to the study of Nature. Sir 
 Joseph Prestwich was a man of this type. His knight- 
 hood at the age of eighty-three, a few months before his 
 death, was a tardy recognition of scientific services of 
 the highest value to the nation. For forty years Prest- 
 wich was a busy merchant in Mark Lane, London, yet 
 during the years of his City career his contributions to 
 geological knowledge were so many and important that 
 almost every hour of his time out of business must have 
 been occupied with them. 
 
 As a youth, Prestwich's inclinations were all for 
 science, but when it became his duty to enter upon a 
 City career he applied himself to business with all the 
 conscientiousness and earnestness of his nature. 
 
 "Perhaps," says his biographer, "there are few endowed 
 as he was who would have had the moral courage to resist the 
 G.D. F 
 
82 DISCOVERY OH. 
 
 fascinations of science. At the outset he planned out his life, and 
 resolved that there should be no interruption to his geological 
 work. The hours at his disposal he allotted, as before, to the 
 identification of fossils and to the analysis of minerals. Time 
 for that work, and for practical chemistry, as well as for his 
 mathematics and reading, had to be found in the early morning 
 before breakfast and after his return from the City at six or 
 seven in the evening, when each hour had its appointed subject. 
 . . . The youth seemed to have an intuitive consciousness 
 that there was something for him to do, that he himself might 
 aspire to demonstrate some truth in God's nature ; and hence- 
 forward every hour he could call his own was set apart to train 
 and gird himself for the task." 
 
 This devotion to truth and knowledge remained with 
 Prestwich to the end of his long life, and led to results 
 of the highest value both to the nation and to science. 
 He was the first to insist upon the importance of geo- 
 logical knowledge in dealing with questions of water- 
 supply, and he became the leading authority upon this 
 subject in England. Water-diviners suggest that some 
 occult influence enables them to locate underground 
 springs or water-courses ; but without expressing any 
 opinion upon their claims we can assert that geological 
 conditions alone determine the presence or absence of 
 underground water, and when these conditions are 
 precisely known the geologist can state without hesitation 
 what the possibility is of finding water. 
 
 A striking instance of the application of geological 
 knowledge to the subject of water supply is given in 
 Prestwich's Life. Having acquired a site for a house 
 overlooking the valley of the Darent above the village 
 of Shoreham, Kent, Prestwich engaged two well-diggers 
 to sink a well 168 feet deep. The boring proceeded, 
 but when a depth of 166 feet was reached, the well- 
 diggers went to the city and sought an interview with 
 their employer, whom they found at his desk. They 
 
iv PURSUIT OF KNOWLEDGE 83 
 
 explained that there was no sign of water, and that in 
 their opinion, it was useless to bore to a greater depth. 
 " Go on," was the quiet rejoinder, " you will come upon 
 water to-morrow. You are within two feet of it." 
 Next day it proved exactly as Prestwich had foretold. 
 He knew the exact level of the springs in the valley, and 
 that water must be found when that depth was reached. 
 
 Another direction in which Prestwich's work found 
 practical application was in connection with British coal- 
 fields. When only twenty years of age, he produced a 
 memoir on the coalfield of Coalbrookdale which was a 
 model of completeness. He spent his holidays examining 
 the surface geology of the district, and descending pits 
 to see the underground structure of the coal seams, and 
 the fossil plants they contained. By minute and patient 
 study he produced a geological map covering an area 
 of about a hundred square miles on the scale of one inch 
 to a mile ; and it was so true to detail that when the 
 Geological Survey mapped the same district later no 
 very important differences were found from this work 
 done by a youth who was practically a City clerk when 
 he accomplished it. 
 
 F. W. Bessel, renowned among astronomers for epoch- 
 making works in many departments of the astronomy 
 of precision, was also a merchant's clerk at Bremen when 
 he calculated the orbit of the celebrated comet of Halley. 
 This youth of twenty, self-taught and occupied with 
 commercial pursuits, solved unaided a problem of high 
 order in mathematical astronomy. He sent his work 
 to H. W. M. Olbers, a physician at Bremen, who for 
 half a century devoted all his spare hours to studies of 
 the skies and the movements of comets. Olbers received 
 Bessel's work with delight, and secured its publication. 
 Two years later he induced Bessel to accept a post as 
 
84 DISCOVERY CH. 
 
 chief assistant in J. H. Schroter's observatory at 
 Lilienthal. 
 
 It was not without a struggle, that Bessel resolved to exchange 
 the desk for the telescope. His reputation with his employers 
 was of the highest ; he had thoroughly mastered the details of 
 the business, which his keen practical intelligence followed with 
 lively interest ; his years of apprenticeship were on the point 
 of expiring, and an immediate and not unwelcome prospect of 
 comparative affluence lay before him. The love of science, 
 however, prevailed ; he chose poverty and the stars, and went 
 to Lilienthal with a salary of a hundred thalers yearly. Looking 
 back over his life's work, Olbers long afterwards declared that 
 the greatest service he had rendered to astronomy was that of 
 having discerned, directed and promoted the genius of Bessel. 
 Miss A. M. Ckrke. 
 
 Many men have made immense fortunes, but few 
 have had the ambition to devote their riches to the 
 advancement of knowledge. Dr. Heinrich Schliemann 
 was one of the few. Before he was ten years old, he 
 had made up his mind that the mighty walls of 
 Tjoy could not have disappeared, but must have been 
 buried by the dust of ages ; and that he would himself 
 some day bring them to light. This object was before 
 him in all his early struggles with poverty. Even when 
 working in an office in Amsterdam for a salary of 32 
 a year, he spent half that sum on living and the other 
 half on self-education, his dinner costing him two-pence, 
 and a fire being an unknown luxury. Under these 
 conditions, and with the Homeric story in his mind, he 
 began the study of modern languages, and became 
 master of seven or eight tongues besides his own, 
 including ancient and modern Greek. By sheer business 
 talent he rose from poverty to great wealth, and he used 
 his fortune to carry out the purpose of his life. 
 
 In 1871 Schliemann began his career as an explorer by 
 an attack on the hill of Hissarlik, near the mouth of 
 
iv PURSUIT OF KNOWLEDGE 85 
 
 the Dardanelles, where he expected to find the city 
 of his dreams. For seventeen hundred years archaeo- 
 logists had been in academic dispute as to the precise 
 position of the city, but Schliemann sought for evidence 
 by actual excavation. He was somewhat of a visionary, 
 but he had sufficient knowledge and insight to know 
 which sites to explore, and he passed all the earth from 
 a site through a sieve, so that nothing of significance 
 should be overlooked. Literary genius, it has been 
 said, is erratic and incalculable, but genius works in 
 science through clear discernment of means and by 
 infinite pains. By these methods Schliemann was able 
 to secure a splendid collection of antiquities, and to 
 disclose a fortress which he believed to be the Pergamos 
 of Troy. Later investigations by Dr. Dorpfeld have 
 shown that the Troy of Homer's epic was a more exten- 
 sive city than that identified by Schliemann, and that 
 as many as nine different towns or villages existed at 
 various times on or around the mound of Hissarlik ; 
 but it was Schliemann who began the accumulation of 
 scientific evidence that enabled the site of the city to be 
 determined. 
 
 In geographical exploration the spirit of adventure 
 has, perhaps, been the stimulating influence more often 
 than the desire to increase scientific knowledge, but 
 whatever the aims, the results have been for the benefit 
 of mankind. Columbus sails west into unknown seas 
 and reaches the Bahamas ; John and Sebastian Cabot 
 land on North America and open a new world to 
 Merchant Venturers ; Vasco da Gama, by sailing round 
 the Cape, reaches India and shows the door to the East ; 
 and Magellan's ship circumnavigates the globe, though 
 the daring explorer did not live to complete the voyage. 
 Of a somewhat different type of maritime explorer was 
 
86 DISCOVERY CH. 
 
 Captain James Cook, whose energy and steadfastness of 
 purpose, joined to his mastery of every detail of his 
 profession, enabled him to carry through the journeys 
 which elucidated the questions as to the amount and 
 extent of the lands in the Southern Ocean, the answer 
 to which had eluded many less competent and persever- 
 ing explorers. Cook was the first to take scientific 
 preventative measures against scurvy the disease 
 which had wrecked the hopes of many intrepid seamen 
 and for his splendid work in this direction he was elected 
 a Fellow of the Royal Society a distinction attained by 
 few geographical explorers. 
 
 In modern times the spirit of scientific exploration is 
 best exemplified in the work of Fridtjof Nansen. In 
 June, 1881, an American exploring ship called the 
 Jeanette foundered in the Arctic at a point north of the 
 New Siberian Islands. Three years later a number of 
 articles which had belonged to the ship were found on 
 the south-west coast of Greenland, having been carried 
 from one side of the Arctic regions to the other by 
 drifting ice. From an examination of the facts relating 
 to this, and one or two similar instances of a similar 
 character, Dr. Nansen arrived at the conclusion, in 1891, 
 that " a current flows at some point between the pole 
 and Franz Josef Land from the Siberian Arctic Sea to 
 the east coast of Greenland." He determined, therefore, 
 to organise an Arctic expedition upon the basis of his 
 conclusion. A strong ship was to be built on such 
 principles as to enable it to withstand the pressure of 
 the ice, and was then to be taken up to the Siberian 
 Islands where the Jeanette foundered, and moored be- 
 tween suitable ice-floes in the hope and conviction that 
 she would be carried to the other side of the North Pole. 
 
 The suggestion met with little encouragement from 
 
iv PURSUIT OF KNOWLEDGE 87 
 
 geographers, but Dr. Nansen persisted in his plans, and 
 sailed from Norway in his famous vessel the Fram, with 
 a crew of twelve, in July, 1893. He disappeared from 
 the civilised world a few weeks later and was not 
 heard of again until June, 1896, when he was met by 
 Major F. G. Jackson on the ice to the south-south-east 
 of Cape Flora. Nansen and his companion, Lieut. 
 Johansen, had left the Fram in March, 1895, in latitude 
 84 N., with the object of exploring the sea to the north, 
 to reach the highest latitude possible, and then go to 
 Spitsbergen via Franz Josef Land. These two hardy 
 men spent fifteen months together amid the Arctic ice, 
 and reached a point in lat. 86 14' N. before they returned 
 and were met by members of the Jackson-Harmsworth 
 expedition. The Fram drifted a little northwards after 
 they left it, and remained in the ice until August, 1896, 
 when she was steered through the last ice-floes out into 
 open water. Shortly after Nansen reached Norway, 
 the Fram touched at Spitsbergen, and a week later the 
 leader and his men met again. 
 
 Since Nansen's journey the North Pole has been 
 reached by Rear- Admiral Peary, but the attainment of 
 this geographical point, though it appeals to popular 
 sentiment, is not of such scientific interest as Nansen's 
 voyage in which inferences derived from observations 
 were proved to be correct. 
 
 The pursuit of knowledge in Polar regions has cost 
 many lives, and the dangers of the ice have enriched 
 heroic literature with the stories of the efforts of many 
 great men, " The famous ones of old." 
 
 How of the field's fortune ? That concerned our Leader ! 
 Led, we struck our stroke, nor cared for doings left and right : 
 Each as on his sole head, failer or succeeder, 
 Lay the blame or lit the praise : no care for cowards : fight ! 
 
 Robert Browning. 
 
88 DISCOVERY CH. 
 
 Among the names of explorers who lost their lives in 
 endeavouring to increase our knowledge of Arctic regions 
 that of Sir John Franklin is most prominent, partly on 
 account of his noble character and heroic death. 1 In 
 1845 Sir John Franklin sailed in the Erebus and Terror, 
 with a party of 129 men, for the purpose of completing 
 a survey of the Arctic coast of Canada, upon which he 
 had been engaged previously. The expedition vanished 
 from the world's ken almost at once, and as nothing had 
 been heard of it three years later a search was begun. 
 In 1859, at Point Victory, on the north-west coast of 
 King William Land, the chief relic of the Franklin 
 expedition was found in the form of a record of successful 
 exploration up to May 28, 1847. But round the margin 
 of the paper containing this record was a second message 
 in a different handwriting : 
 
 April 25th, 1848 : the ships were deserted on April 22nd, having 
 been in the ice since September 12th, 1846. Sir John Franklin 
 died June llth, 1847, and the total loss to this date has been 
 nine officers and fifteen men. The rest (105 in number) landed 
 here and start to-morrow for the Great Fish River. 
 
 The ships had been provisioned for a period ending 
 July, 1848, and in April of that year the retreat by land 
 was begun. Not a soul survived. Franklin had suc- 
 ceeded in his object, the North- West Passage had been 
 discovered ; but the ice had taken its toll. Not until 
 1906 did any ship traverse the North- West Passage, 
 but in that year the Gjoa, under Roald Amundsen, 
 reached the haven of San Francisco, having left Chris- 
 tian ia in May, 1903. 
 
 In the interests of scientific investigation it was 
 arranged that from August, 1882, simultaneous obser- 
 
 1 The toll of the ice here counted is chiefly that of an article by 
 B. C. W. in The School World for March, 1913. 
 
iv PURSUIT OF KNOWLEDGE 89 
 
 vations should be taken in a series of international 
 circumpolar stations. The United States expedition to 
 Lady Franklin Bay was under the command of Lieu- 
 tenant A. W. Greely, who established his camp in that 
 high latitude, and made many arduous sledge journeys. 
 On account, however, of the failure of the relief ships 
 to reach him after his work had been accomplished, he 
 had to depend entirely upon his own efforts in returning 
 homewards. In 1884 the few men left were only just 
 alive when they heard the whistle of a steamer. Two 
 men struggled out from the camp, and the search party, 
 entering the cove by boat, saw one of them make a 
 signal and approach ; twice he fell. When the rescuers 
 reached Greely 's tent they cried, " Greely, is that you ? " 
 In a faint, broken, hesitating voice came the answer, 
 " Yes yes seven of us left here we are dying like 
 men. Did what I came to do beat the best record." 
 
 The map of Greenland contains two names along its 
 northern shores Peary Land and Mylius Erichsen Land. 
 Rear-Admiral R. E. Peary attained the North Pole as 
 a crowning result of twenty-three years' devotion to 
 Arctic exploration ; but one of his most remarkable 
 and hazardous journeys is commemorated in the name 
 Peary Land. He explored the north-west coast of 
 Greenland, and crossed the interior in its neighbourhood. 
 This success left only the north-east coast unexplored, 
 and in 1906-8 a Danish expedition, under the leadership 
 of Erichsen, proceeded thither for the purpose of scientific 
 exploration. Erichsen and two companions on a sledge 
 journey were confined during the summer of 1908 to a 
 small territory near Denmark Fiord. By the middle of 
 the summer their food was exhausted, and they had no 
 footgear. They attempted to reach a depot ; daily 
 they crawled out of dilapidated sleeping bags and pushed 
 
90 DISCOVERY OH. 
 
 forwards barefooted over the inland ice in the hope of 
 leaving their records where their comrades could find 
 them. Bronland was the last survivor ; he crawled the 
 last few miles to the depot, ate some of the food there, 
 wrote his last report, wrapped himself in his fur and 
 died. His report concludes : 
 
 I perished in 79 N. lat., under the hardships of the return 
 journey over the inland ice in November. I reached this 
 place under the waning moon, and cannot go on because of my 
 frozen feet and the darkness. The bodies of the others are 
 in the middle of the fiord. Hagen died on November 15th, 
 Mylius Erichsen some ten days later. 
 
 The records of the scientific work of these three heroes 
 were retrieved by an expedition under the leadership of 
 Einar Mikkelsen, which reached Greenland in 1909. They 
 were found in a cairn near Erichsen's summer camp. 
 
 But the records of polar exploration contain no more 
 inspiring story than that of the way in which Captain 
 Scott and his companions of the British Antarctic 
 Expedition met their death in returning from the South 
 Pole early in 1912. Captain Scott, Dr. Wilson, Capt. 
 Gates, Lieut. Bowers and Petty Officer Evans, after 
 pulling their sledges alone for 147 miles, reached the 
 Pole on Jan. 18th, 1912. When they began the return 
 march, the season was unduly advanced, and progress 
 delayed by the sickness and subsequent death of Evans. 
 Yet, despite this and exceptionally severe weather and 
 difficulties of travel, they persisted in carrying their 
 collection of specimens, though this must have increased 
 their labours. Capt. Oates suffered severely from frost- 
 bite, and his companions delayed their progress to help 
 him. Capt. Scott wrote : 
 
 He was a brave soul. He slept through the night, hoping not 
 to wake, but he awoke in the morning. It was blowing a 
 
iv PURSUIT OF KNOWLEDGE 91 
 
 blizzard. Gates said, " I am just going outside and I may 
 be some time." He went into the blizzard, and we have not 
 seen him since. 
 
 Oates felt death upon him, and knowing he held his 
 companions back, went from them to meet it. No more 
 appropriate epitaph was ever written than " Here- 
 abouts lies a very gallant gentleman," marked upon a 
 post near where Oates walked to his death amid the 
 Antarctic snows. 
 
 On March 21st, 1912, Capt. Scott, Dr. Wilson and 
 Lieut. Bowers were forced, on account of a blizzard, to 
 camp in latitude 79 40' S., eleven miles from a depot 
 where there was at least a ton of stores. They had 
 food for two days and fuel for one hot meal. The 
 blizzard prevented them from leaving their tent, and 
 when they had been imprisoned for four days, Capt. 
 Scott wrote his last message and his final appeal on 
 behalf of those who are left behind. He wrote : 
 
 We took risks we know we took them. Things have come 
 out against us, and therefore we have no cause for complaint, 
 but bow to the will of Providence, determined still to do our 
 best to the last. 
 
 The message signed, Capt. Scott placed it with his diary 
 between his head and the tent-pole, and, leaning against 
 the pole, met the end. The remains of Capt. Scott and 
 his two companions were not found until the following 
 November, when the heroes were reverently laid to rest. 
 But though they have entered into their long sleep, 
 from the solitude of the polar waste of snow and ice 
 where they lie their spirits have risen triumphant to 
 testify to the world the greatness of human endeavour 
 and the glory of self-sacrifice for the purpose of increasing 
 knowledge. 
 
CHAPTER V 
 BELIEF AND EVIDENCE 
 
 We see only what we know. Goethe. 
 
 Science is, I believe, nothing but trained and organised 
 
 common sense. Huxley. 
 Let us first understand the facts, and then we may seek the 
 
 cause. Aristotle. 
 The ivork of science is to substitute facts for appearances, 
 
 and demonstrations for impressions. Kuskin. 
 And Reason now through number, time, and space 
 Darts the keen lustre of her serious eye ; 
 And learns from facts compared the laws to trace 
 Whose long procession leads to Deity. J. Beattie. 
 * / hope that my children, at least, if not I myself, will see the 
 
 day, when ignorance of the primary laws and facts of 
 
 science will be looked upon as a defect, only second to 
 
 ignorance of the primary laws of religion and morality. 
 
 C. Kingsley. 
 
 THERE is a common impression that the conclusions 
 arrived at by men of science are of the nature of beliefs, 
 and have, therefore, no firmer basis than that of con- 
 viction. Nothing could be farther from the truth. 
 From his earliest days the student of science is trained 
 to ask for evidence before arriving at a judgment ; and 
 he should hesitate to pass an opinion upon a subject 
 with which he is not familiar. Any beliefs he may hold 
 as to natural phenomena belong to quite a different 
 category from that of knowledge gained by the critical 
 
v BELIEF AND EVIDENCE 93 
 
 examination of observed facts. No subject is too 
 trivial for inquiry, and no relationship must be regarded 
 as impossible from a priori considerations, but the 
 scientific mill must have material to work upon before 
 the value of the product can be estimated. It is per- 
 missible to doubt whether the grain is worth grinding, 
 but not to deny it a trial ; for without a test any belief 
 may be held as to its quality. Whether you doubt or 
 believe is of no consequence whatever in scientific 
 things if you cannot give reason for the position you 
 occupy. There must be facts and there must be thought 
 about them before any statement of substantial value 
 can be made as to natural objects and phenomena. 
 
 Popular impressions and beliefs relating to weather 
 are often based upon casual observations, and have 
 little foundation in fact. Yet every belief of this kind is 
 worthy of examination, and if it has not been investi- 
 gated no man of science is justified in asserting that it 
 is untrue. But when such an inquiry has been made, 
 and the evidence has failed to support popular opinion, 
 we cannot do other than state that the case has not 
 been proved. Two such examples may here be given ; 
 one as to alleged change of climate and the other as to 
 a connection between the moon and the weather. 
 
 Many people believe that the British climate has 
 undergone considerable changes in comparatively modern 
 times. " The winters (or the summers) are not what 
 they were when I was young," is a statement frequently 
 made ; but when meteorological records are examined, 
 they show that the temperature, rain, snow, frost and 
 like atmospheric phenomena are much the same at the 
 present time as they were in the early days of the 
 declining generation. Going back so far as trustworthy 
 observations with meteorological instruments exist, no 
 
94 DISCOVERY 
 
 CH. 
 
 evidence can be found to justify the common belief 
 that the climate of England has changed. When there 
 were few instruments, or none, the tendency of writers 
 or diarists of those days would be to pass ordinary 
 weather conditions unnoticed, and to refer only to 
 unusual experiences. 
 
 The diaries of Evelyn and Pepys provide faithful 
 chronicles of noteworthy aspects of the weather during 
 the latter half of the seventeenth century ; and a careful 
 examination of them has been made with the view of 
 discovering whether any marked differences exist 
 between the seasons then and now. Consider the winter 
 season, for example. The instances of snow recorded 
 by Evelyn and Pepys are surprisingly few, being only 
 mentioned in thirteen winters in the period covered by 
 the diaries (1648-1703), and only three of these falls 
 appear to have been exceptional. At least eleven very 
 mild or wet winters occurred in Evelyn's lifetime, and 
 prolonged or severe frosts including that of 1683-4, 
 wKen coaches plied to and fro on the Thames were 
 experienced in about ten of the winters. 
 
 The conclusion arrived at, after considering all the 
 information available, is that cold winters were not 
 more frequent, or mild winters less so, in the latter half 
 of the seventeenth century than they have been in the 
 last fifty years. Spring, summer and autumn have 
 also preserved much the same general characteristics, 
 with occasional noteworthy variations. An inquiry 
 into the facts, therefore, affords no ground for the 
 belief that the seasons of our time are sensibly different 
 from those of our proximate forefathers. 
 
 Belief in an old-fashioned Christmas weather, with 
 snow six feet deep, and skating for weeks on end, is 
 fostered by most writers and artists who describe and 
 
v BELIEF AND EVIDENCE 95 
 
 depict Christmas scenes. Snow is apparently as essential 
 a part of every Christmas story or picture as the ghost 
 or the haunted chamber, yet our own experience tells 
 us that one is almost as rare as the other, and that the 
 association of snow with that day is more a matter of 
 imagination than of fact. If, however, we look further 
 back, a reason may be found for colder weather at 
 Christmas than that now usually experienced. On 
 account of the change from the Julian to the Gregorian 
 Calendar in 1752, Christmas now occurs thirteen days 
 earlier than it did. Old Christmas Day, Jan. 7, 
 marks the date upon which the festival was formerly 
 celebrated ; and there have been considerable falls of 
 snow after Christmas which would have occurred at 
 Christmas or before if the Julian Calendar had been 
 still in use. 
 
 Tradition, and general impressions of elderly people, 
 are, indeed, of little value in deciding whether any 
 permanent change of climate has taken place. The 
 only trustworthy test is provided by records of rain- 
 fall, temperature or other meteorological observations 
 made systematically with suitable instruments. Such 
 records go back for 150 years or so, and when they are 
 examined critically they are found to give no decided 
 indication of any progressive change, either for the 
 better or worse. From an examination of old records, 
 and of the long series of observations made at Green- 
 wich, Sir John Moore was able to show to the British 
 Association in 1908 that no appreciable change has 
 taken place in the climate of the British Isles during 
 the past six centuries. It is of no use to place a 
 popular belief in such a change by the side of such 
 a conclusion arrived at as the result of open-minded 
 and careful inquiry. The responsibility of proving 
 
96 DISCOVERY 
 
 CH. 
 
 that a change of climate has occurred lies with those 
 who believe in it. 
 
 The origin of the belief in a permanent change of 
 climate is probably to be found in the fact that weather 
 everywhere has a tendency to vary in a cycle of about 
 thirty-five years, referred to long ago by Francis Bacon, 
 and established in detail by Prof. E. Bruckner, of Berne, 
 in our own times. In his essay " Of Vicissitude of 
 Things," Bacon remarks : 
 
 They say it is observed in the Low Countries (I know not in 
 what part) that every five and thirty years the same kind and 
 suit of years and weathers comes about again ; as great frosts, 
 great wet, great droughts, warm winters, summers with little 
 heat, and the like ; and they call it the " Prime." It is a thing 
 I do the rather mention, because, computing backwards, I have 
 found some concurrence. 
 
 Neglecting individual years, it may be stated that for 
 about half this cycle the weather is warmer and drier 
 than the average, and for the other half colder and wetter. 
 Or, expressed in another way, wet and cold periods, or 
 warm and dry periods, occur at intervals of about 
 thirty- five years. It is impossible to predict whether 
 any particular year will be colder or warmer than usual, 
 or whether the rainfall will be above or below the average, 
 but Bruckner's cycle certainly does express a general 
 truth, though not very precisely, when applied to the 
 whole earth. In the seventies of the nineteenth century 
 there was a series of very wet years in the British Isles, 
 culminating in the black year of 1879, memorable to 
 all who were then engaged in agriculture. Much the 
 same phase of the cycle was reached in 1912, and that 
 year proved almost as bad for many British farmers as 
 the ruinous year thirty-three years earlier. 
 
 An interesting instance of the application of this 
 
v BELIEF AND EVIDENCE 97 
 
 cycle and how it- led to a belief in the change of climate, 
 is contained in the following statement : 
 
 The time of the " boom " in western Kansas and Nebraska, and 
 in eastern Colorado, in the decade 1880-90, followed one of 
 Bruckner's wet periods, and the collapse of the " boom " came 
 when the drier period advanced. Farmers who went out on 
 to the high plains in the years of slightly greater rainfall preceding 
 the " boom," and who lost all their capital, and more too, in the 
 vain attempt to raise their grain in the years which followed, 
 could with difficulty be convinced that the climate of the plains 
 had not permanently changed for the worse. The impression 
 left upon their minds, and upon the mind of anyone who saw 
 the country later, was one of decreasing rainfall, unsuccessful 
 agriculture and financial ruin. Within more recent years, in 
 this same region of Kansas, with a somewhat increased rainfall 
 during a wetter cycle, but without any permanent change 
 to a wetter climate, the intelligent choice of cereals better 
 adapted to the soil and climate, and the rational use of the 
 available water supply, have wrought a wonderful change in the 
 aspect and economic value of the State. Prof. R. de C. Ward. 
 
 As with the farmers of Kansas, so many other people 
 have arrived at their conclusions as to a progressive and 
 permanent change of climate, from general impressions 
 produced by a succession of several bad or good years. 
 In the perspective of the past the individual years are 
 not seen separately when viewed from another stage of 
 a lifetime, and characteristics of periods of weather in 
 youthful days are apt to be used as comparison with 
 individual years of middle life or old age. However 
 firm may be the belief that this generation experiences 
 different weather from that of its fathers or grand- 
 fathers, the fact remains that no such change in historic 
 times has been established. 
 
 Beliefs in the influence of the moon upon the weather 
 are enshrined in the folk-lore of all countries. We 
 cannot attempt here to classify and analyse the hundreds 
 
 G.D. Q 
 
98 DISCOVERY CH. 
 
 of proverbs which express the views of different peoples 
 in different provinces as to lunar influence upon weather, 
 but it is worth while to give the results of a few inquiries 
 into alleged connections. Until similar studies have 
 tested the various assertions as to the dependence of 
 weather upon changes of the moon, science is not 
 justified in denying the existence of any such relationship. 
 Honest doubt is commendable, but when it leads to dog- 
 matism it passes outside the realm of scientific thought. 
 One widespread belief for which no justification has 
 been found is that " La Lune mange les Nuages," or, 
 in the language of sailormen, " the full moon eats up 
 the clouds." Sir John Herschel refers to the tendency 
 of clouds to disappear under the Full Moon as a meteoro- 
 logical fact for which it is necessary to seek a cause, 
 but his conclusion has found no support from systematic 
 observations. To obtain information upon the subject, 
 the Rev. S. J. Johnson compared the state of the sky 
 at moonrise and at midnight on the day of Full Moon 
 for fifteen years ; and his observations, communicated 
 to the Royal Astronomical Society in 1894, confirmed 
 the opinion now held by almost every astronomer, 
 namely, that the Full Moon has no effect in breaking 
 up clouds. Mr. W. Ellis made a detailed examination 
 of Greenwich observations with the view of discover- 
 ing whether any such effect exists. The results of the 
 inquiry showed that there is in general a maximum 
 cloudiness in the forenoon and a minimum in the evening, 
 but this has no relation to the position or phase of the 
 moon. A change from a cloudy to a clear state in the 
 evening sky is much more likely to attract attention 
 when occurring near to Full Moon, and this may have 
 given rise to the popular belief that the moon itself 
 possesses the faculty of clearing away clouds. 
 
v BELIEF AND EVIDENCE 99 
 
 The subject has been investigated in other countries 
 than Great Britain. Observations of the night sky at 
 Potsdam for the six years from 1894 to 1900 failed to 
 show any cloud- dispersing power for the Full Moon. 
 It was found, indeed, that there was a maximum amount 
 of cloud visible shortly after Full Moon and a minimum 
 about the time of New Moon. This result is to be 
 expected if the moon has no influence upon clouds ; 
 for moonlight makes clouds visible. At Kenilworth 
 (Kimberley) Mr. J. R. Sutton has found that certain 
 clouds appear to dissolve at sunset, but the rising moon 
 makes them visible again. Observations made at 8 p.m. 
 over a period of seven years show considerably more 
 cloud between the third and eighteenth days of the 
 moon's age than between the eighteenth and third, so 
 that here again the evidence is opposed to the popular 
 view. At any rate, we are justified in declining to accept 
 the power of the moon to disperse clouds until proof of 
 this capacity is forthcoming from those who believe in it. 
 
 As the moon is chiefly responsible for the rise and fall 
 of the tides, it seems reasonable to suppose that the 
 earth's atmosphere is affected in the same way, and that 
 there are air-tides which may vary through the lunar 
 month, like the spring and neap tides of the sea. Daily 
 atmospheric tides due to the moon have, in fact, been 
 detected in records of barometer readings made at 
 Brest, St. Helena, Cape Horn, Batavia, and Singapore. 
 In 1895 M. Bouquet de la Grye proved that the curves 
 of atmospheric pressure obtained at these places show 
 clearly a regular ebb and flow twice a day in accordance 
 with the position of the moon. The effect, however, is 
 of a very minute character. The maximum difference 
 attributed to the influence of the moon is about one- 
 fiftieth of an inch in the height of the mercury in a 
 
100 DISCOVERY CH. 
 
 barometer. Though this amount is well within the 
 limits of accurate measurement, it is too small to be 
 distinguishable with an ordinary barometer. A rise or 
 fall of one-fiftieth of an inch is scarcely worth considering 
 as a sign of change of weather, yet that is the greatest 
 deviation for which the moon can be held directly 
 responsible. While, therefore, air-tides can be detected, 
 they are of no value whatever as a means of forecasting 
 weather. 
 
 The only definite association that can be regarded as 
 established between changes of the moon and weather 
 relates to the occurrence of thunderstorms, and it is 
 noteworthy that this is overlooked completely in pro- 
 verbial philosophy. Thunderstorms are found to be 
 slightly more frequent near New Moon and the First 
 Quarter than near Full Moon and the Last Quarter. 
 This is clear from the adjoining table, which is given as 
 much to show that the lunar influence has been the 
 subject of many investigations in different countries 
 and extending over long periods of years as to illustrate 
 the kind of result obtained. 
 
 Referring to this table, Prof. W. H. Pickering, who 
 brought the results together, remarks : 
 
 The number of observations here collected seems to be large 
 enough to enable us to draw definite conclusions, without fear 
 that further records will revise or neutralise them. From these 
 observations we conclude that there really is a greater number 
 of thunderstorms during the first half of the lunar month than 
 during the last half ; also, that the liability to storms is greatest 
 between New Moon and the First Quarter, and least between 
 Full and Last Quarter. Also we may add that while theoretically 
 very interesting, the difference is not large enough to be of any 
 practical importance. 
 
 So far, then, as earnest investigations have been 
 carried out with the purpose of associating the weather 
 
BELIEF AND EVIDENCE 
 
 101 
 
 with the various phases and positions of the moon, no 
 connection has been found definite enough to be of 
 
 THE MOON'S PHASES AND THUNDERSTORMS. 
 
 Station. 
 
 Authority. 
 
 Years. 
 
 New and 
 First 
 Quarter, 
 (per cent.) 
 
 Full and 
 Last 
 Quarter, 
 (per cent.) 
 
 Kremsmiinster 
 
 Wagner 
 
 86 
 
 54 
 
 46 
 
 Aix-la-Chapelle 
 
 Polis 
 
 60 
 
 54 
 
 46 
 
 Batavia, Java 
 
 Van d. Stok 
 
 9 
 
 52 
 
 48 
 
 Gotha 
 
 Lendicke 
 
 9 
 
 73 
 
 27 
 
 Germany 
 
 Koppen 
 
 5 
 
 56 
 
 44 
 
 Glatz County 
 
 Richter 
 
 8 
 
 62 
 
 38 
 
 N. America 
 
 Hazen 
 
 1 
 
 57 
 
 43 
 
 Prague 
 
 Grass 
 
 20 
 
 51 
 
 49 
 
 > 
 
 ,, 
 
 20 
 
 53 
 
 47 
 
 Gottingen 
 
 Meyer 
 
 24 
 
 54 
 
 46 
 
 Greenwich 
 
 MacDowall 
 
 13 
 
 54 
 
 46 
 
 Madrid 
 
 Ventatasta 
 
 20 
 
 52 
 
 48 
 
 Providence, R.I. 
 
 Seagrave 
 
 6 
 
 49 
 
 51 
 
 service in the actual work of weather prediction. Any 
 observer who can bring forward evidence which will 
 establish such a connection will make a notable contri- 
 bution to meteorological science, and at the same time 
 confer a benefit upon humanity. Meteorologists are 
 prepared to adopt any rule or relationship which is of 
 assistance in preparing their weather forecasts ; and the 
 fact that they take no account of lunar phases or the 
 directions of the moon's horns which can be deter- 
 mined many years in advance for any latitude on the 
 earth shows that lunar influence has not yet been 
 brought within the sphere of practical science. 
 
 There is a vast difference between forecasts based 
 upon substantial truths of science and those made by 
 
102 DISCOVERY OH. 
 
 irresponsible weather prophets in almanacs popular in 
 agricultural districts and among credulous people. 
 Appropriately can it be said of such predictions : " The 
 prophets prophesy falsely and the priests bear rule by 
 their means ; and my people love to have it so." No 
 doubt some of the forecasts made by " Zadkiel," " Old 
 Moore " and " Raphael " in their almanacs, and by 
 other soothsayers who think they have discovered 
 weather cycles and causes which have eluded the wisest 
 meteorologists in the world, do prove to be correct ; 
 but it would be strange if these coincidences of prediction 
 and realisation did not occur. 
 
 No man of science familiar with the many variable 
 factors which determine the character of the weather 
 would have the temerity to make such predictions as are 
 put before an indulgent public by these oracles, whose 
 theories break down immediately they are faced with 
 facts. Caution comes with knowledge ; and confident 
 assertion as to the weather to be expected day by day 
 even next week, in a particular part of the country, must 
 lead to discomfiture when promise is made to face per- 
 formance. The predictions in most popular almanacs 
 are based upon the time of day the moon enters into one 
 of its four quarters ; and any success achieved by them 
 may be ascribed to the laws of chance. 
 
 In addition to the moon, the stars and planets are 
 believed by some people to exert an influence upon the 
 weather, the belief being a survival of the days of 
 astrology. So far as the stars are concerned, the 
 positions they will occupy at 10 o'clock to-night will be 
 practically the same as will be presented at the same 
 time a hundred years hence. Moreover, on account of 
 the earth's rotation on its axis, every star in the heavens 
 shines upon some part of the earth every day. No one 
 
v BELIEF AND EVIDENCE 103 
 
 who has considered the facts that the apparent move- 
 ments of the stars are entirely due to the daily spin of 
 the earth, and the annual journey round the sun, is able 
 to believe that the weather can be determined by the 
 aspects of the stellar heavens at any time of day or year. 
 Certain groups of stars are visible at particular seasons, 
 but they have nothing whatever to do with the cause 
 of the seasons, which would, indeed, be of precisely the 
 same character as they are now, even if every star in 
 the sky ceased to shine. The stars are, in fact, much 
 too far removed from the solar system to take any part 
 in causing weather changes. 
 
 The nearest of all the stars is a quarter of a million 
 times farther away from us than is the sun ; and the 
 heat we receive from a star is so small in amount 
 that it can only be detected with instruments of 
 extreme delicacy. Whatever the temperatures of the 
 stars may be, the stellar heat that reaches the earth 
 is almost inappreciable. The best measurements avail- 
 able, made by Prof. E. L. Nichols at the Yerkes Obser- 
 vatory, California, with an instrument capable of 
 detecting a difference of temperature of less than the 
 ten-millionth part of a degree on a Centigrade ther- 
 mometer, shows that a square foot of the earth's surface 
 receives from the bright reddish star Arcturus only as 
 much heat as would be received from a standard candle 
 nearly six miles away, even if none of the heat of the 
 candle were absorbed during the passage of the rays 
 through the air. To produce the same heating effect 
 as the brilliant bluish- white star Vega, a standard candle 
 would have to be taken to a distance of nearly nine miles. 
 
 Dr. S. Chapman estimates that the total starlight is 
 only about equal to that of a one candle-power lamp 
 at a distance of nearly twelve yards, or of a sixteen 
 
104 DISCOVERY on. 
 
 candle-power lamp at 47 yards' distance ; so that the 
 heat received from the whole of the stars is far too small 
 to have any observable influence upon the atmospheric 
 movements which produce changes of weather. 
 
 As regards heating effect, the planets are in the same 
 case as the stars. From the planet Jupiter, the heat 
 received is nearly five times more intense than from 
 the star Vega, but even that is next to nothing, and is 
 altogether negligible in comparison with solar heat. It 
 is, therefore, not remarkable that no amount of juggling 
 with planetary conjunctions and oppositions has ever 
 revealed a combination of the slightest service in weather 
 prediction. It is possible, of course, that rays of an 
 undiscovered kind are received from certain celestial 
 bodies, and that these are operative in producing 
 weather changes, but the fact remains that no relation- 
 ship of practical value has been made out between the 
 movements apparent or real of the moon, stars, or 
 planets and the weather of any part of the earth. 
 
 Animals depend so much upon weather for their supply 
 of food, that their sensitiveness to weather changes, 
 which may deprive some of them of a meal, is not 
 strange. It is unnecessary to assume that they have any 
 special sense in this respect any prophetic instinct that 
 enables them to foretell the character of coming seasons. 
 They may be affected by atmospheric conditions which 
 are not detected by human nature in general, and they 
 respond to these conditions by their actions, but these 
 signs only indicate the weather to be expected in the 
 immediate future. Sufficient for living creatures to 
 know what the proximate weather will be, and their 
 prescience goes no farther than that, as is shown by the 
 myriads of birds and other animals that are destroyed 
 every year by severe storms and untoward changes. 
 
v BELIEF AND EVIDENCE 105 
 
 Plants even more than animals show by their condition 
 the weather of the past or present rather than that of 
 the future. Variations of the temperature, moisture 
 and electrical state of the air are doubtless reflected 
 readily by some plants and flowers, but the same varia- 
 tions can be detected by other means. Whether we 
 interpret the closing of the scarlet pimpernel the 
 ploughman's weather-glass the trembling of aspen 
 leaves, or the increased odour of flowers, we must 
 recognise that these are only signs of possible showers 
 coming soon, and that no indications can be given of 
 the weather to follow afterwards. 
 
 The conditions of trees in the spring, whether the oak 
 comes into leaf before the ash, or the ash before the oak 
 as it is sometimes said to do are determined entirely 
 by past performances of the weather, and have nothing 
 whatever to do with the future. Similarly, when bushes 
 have plenty of berries, it is because conditions were 
 favourable for the production of their fruit when they were 
 in flower, and not because the coming winter is to be 
 severe. The temperature, sunshine, rainfall, abundance 
 of particular insects, and other past causes which affect 
 the birth and growth of plants, decide whether the 
 berries shall be few or many, and not the future conditions. 
 
 In some years, no doubt, popular confidence in the 
 supply of beneficent berries for hungry birds is justified, 
 while in other years it is not, but people forget their 
 failures and remember only their successes, and this 
 infirmity of human nature causes many beliefs to endure 
 which can find no support in the results of critical study. 
 Records of the behaviour of plants and animals under 
 different atmospheric conditions and in different seasons 
 are of interest to the meteorologist, but they have not 
 yet been found of any service in making forecasts of 
 
106 DISCOVERY OH. 
 
 weather over periods longer than those which at present 
 limit his predictions. 
 
 Relationships may be found long before they are 
 understood, but in all cases it is desirable to be assured 
 of their truth before attempting to explain them. The 
 evidence for the beliefs mentioned already is altogether 
 insufficient to satisfy any critical mind, yet many 
 " wise-saws " which serve for making estimates of 
 weather changes a few hours, or even a day or two, in 
 advance, are contained in the accumulated wisdom of 
 ages, often enshrined in proverbs and folk-lore. The 
 shepherd and the sailor, the hunter and the tiller of the 
 ground, learnt to read the face of the sky and to interpret 
 its promises and warnings long before any scientific 
 foundations for their beliefs had been discovered. 
 
 There is no better example of this than the numerous 
 proverbs of different times and nations referring to the 
 weather outlook foretold by a red sunset or red sunrise. 
 " When it is evening, ye say, ' It will be fair weather : 
 for the sky is red.' And in the morning, ' It will be foul 
 weather to-day : for the sky is red and lowring.' ' So 
 spake Christ to the Pharisees and Sadducees ; and He 
 used this common belief of His day as an illustration of 
 the self-satisfying spirit which is content with the 
 obvious and seeks not to discern the " signs of the times." 
 
 As a general rule for weather prognostication it is as 
 true in the British Isles as it was in Palestine that 
 
 " Sky red in the morning 
 
 Is a shepherd's sure warning ; 
 Sky red at night 
 Is the shepherd's delight." 
 
 The connection between the weather which usually 
 follows redness of sunrise or sunset is a statement of fact 
 derived from long experience ; the explanation could 
 
v BELIEF AND EVIDENCE 107 
 
 only be given when the effects of atmospheric dust and 
 moisture as filters of sunlight had been studied. Sunlight 
 is white light, and when we see the sun red, it is because 
 the blue rays in the original beams have been dissipated 
 by the intervening air, or rather by the dust particles in 
 the air and the water droplets which surround them. 
 
 A red sky in the evening indicates that there are plenty 
 of dust particles in the air, and that water-vapour is 
 beginning to be condensed upon them, but relatively few 
 water droplets are being formed, and it is unlikely that 
 they will increase sufficiently to cause rain during the 
 succeeding twenty-four hours. A red sky in the morning 
 shows, however, that the droplets around the dust 
 particles are being protected from becoming smaller by 
 a blanket of overlying moisture, otherwise they would 
 soon be driven into vapour again by the rising sun's 
 rays. The conditions are, therefore, favourable to the 
 growth in size of the droplets, and rain will probably 
 fall during the day. 
 
 The association of a red sky with weather thus admits 
 of complete physical explanation, but it is not at all 
 necessary that the reason should be forthcoming for 
 every fact. It is, however, desirable to distinguish 
 between accurate observation and traditional belief 
 which asks for acceptance without inquiry into the 
 evidence of its truth. 
 
 In the prediction of good and bad seasons, meteoro- 
 logists are to-day little in advance of the priests and 
 astronomers of ancient Egypt or Assyria ; for the only 
 forecasts that can be made are based upon the recurrence 
 of cycles of changes. Unfortunately, this is true to a 
 great extent because, although the knowledge of periodic 
 changes in the earth's meteorology over a cycle of years 
 is of a more exact nature than formerly, the fundamental 
 
108 DISCOVERY CH. 
 
 cause of the variations from year to year has yet to 
 be found. Ancient astronomers were able to predict 
 eclipses with fair accuracy, because they knew the 
 eclipse cycle, though they did not understand the true 
 relationships existing between the sun, moon and earth 
 as members of the solar system, or the law of gravitation. 
 The discovery of this law was the key to all cycles caused 
 by the movement of members of our system, and in the 
 light of it predictions of eclipses are now made. On 
 the other hand, no master-key has been found which 
 will enable the, cycles extricated from meteorological 
 records to be seen as consequences of natural laws. 
 
 The sun is responsible for the great movements of the 
 atmosphere which circulates around the solid earth. 
 The various kinds of messages which its rays bear to 
 the earth are being accumulated in solar observatories, 
 and persistent efforts are being made to understand 
 the code in which they are written. Little by little 
 the language of the sun is being pieced together, but 
 we still await the discovery of an inscription which will 
 provide a key to solar influences, as the Rosetta stone 
 did for Egyptian hieroglyphs. When this key has been 
 found, it will be possible to predict the seasonal weather 
 from year to year in advance ; but that time is not yet. 
 
 To an observer unfamiliar with the game of chess, 
 the movements of the different pieces upon the board 
 by the players are unintelligible. A master of the game 
 sees, however, not only the disposition of the pieces at 
 a given moment, but also for several moves ahead. As 
 regards weather prediction, meteorologists are at present 
 in the position of a spectator knowing one or two simple 
 moves in the air and these limited to a small portion of 
 the board. They do not see the whole board at one 
 time, though this is essential for an estimate to be made 
 
v BELIEF AND EVIDENCE 109 
 
 of the effect of a change of position of one piece upon 
 the future relationship of the others. 
 
 Though there is always comfort in prayer the comfort 
 that comes from trust in a power other than ourself 
 it would be just as reasonable to pray that the moon 
 should change its course in order to give additional 
 light when required, that the sun's heat should increase 
 or decrease to suit particular needs, or the earth's 
 rotation be altered from time to time, as to pray that 
 the circulation of the atmosphere should be adapted to 
 the wants of a particular country or district. Because 
 we can predict the positions of the moon, sun, earth 
 and other bodies we do not pray to alter them, but the 
 movements of the air are subservient to like law and in 
 the course of time will be predicted in like manner. 
 
 A clergyman who was asked to pray for rain is said to 
 have replied, " My good friends, what is the use of 
 praying for rain whilst the wind is in the east." It may 
 be said, of course, that everything is possible to 
 Omnipotence behind the universe ; and the only answer 
 to this must be that it would be equally illogical to pray 
 for changes in the aspects of the heavens as that winds 
 should have their movements altered for the benefit of 
 particular people or interests. 
 
 Belief in works rather than faith in prayer is responsible 
 for the attempts to produce rain in drought-stricken 
 districts by means of explosives. It has been shown 
 that such experiments are a useless expenditure of money, 
 and they have been condemned by the best meteoro- 
 logists of Europe and America. In 1908 a meteoro- 
 logist who was ordered to watch the result of rain-making 
 experiments carried out in a district of New Zealand 
 reported that " the explosions had apparently no more 
 effect on the vast expanse of the air than would the 
 
110 DISCOVERY CH. 
 
 striking of a match in a room." The belief has been 
 shown over and over again to have no foundation, yet 
 rain-wizards are still able to carry on their profession 
 even in civilised countries. 
 
 The possibility that rain or drought can be produced 
 by human means is never questioned by barbarians, who 
 have their professional rain-makers and great medicine 
 men, and superstitiously attribute to them all power 
 over Nature. A few years ago elaborate experiments to 
 determine whether rain could be caused by explosion were 
 made in connection with the United States Government, 
 at an expense of thousands of pounds, but the results 
 proved that nothing of the nature of rain was produced 
 by the bombardment. In fact, rain falls according to 
 the general weather conditions existing at a place, and 
 is altogether independent of the puny efforts of man to 
 change the nature of the clouds. When rain does occur 
 in the wake of a rain-wizard, a glance at the meteoro- 
 logical chart of the day will show that it is a natural 
 consequence of the distribution of temperature and 
 pressure, and is usually predicted by the Meteorological 
 Office. It is strange that many people ignore this fact, 
 and ascribe any rainfall that may take place to the acts 
 of the professional rain-maker. 
 
 Many educated people believe that rain follows great 
 battles, the general opinion being that the noise of the 
 guns or the combustion of the explosives in some way 
 affects the clouds, and causes them to precipitate their 
 moisture. During the first ten weeks of the European 
 War, when there was little rain, though heavy gun-firing 
 was almost continuous, nothing was heard of the belief, 
 but when this was followed by an excessively wet period 
 we were again assured by the newspapers that big battles 
 invariably produce rain. The human tendency to forget 
 
v BELIEF AND EVIDENCE 111 
 
 facts or events which are contrary to a cherished convic- 
 tion, and remember only those which support it, is respon- 
 sible for the existence of this and many other like beliefs. 
 
 So firm is the fallacy as to explosions causing rain 
 that in the year 1911 a member of the House of Commons 
 asked the First Lord of the Admiralty in Parliament 
 " whether he would arrange for the fleet to carry out 
 their heavy gun-firing practice round the coast at 
 some other period of the year than in the middle of 
 the harvest-time, when the resulting heavy rain may 
 cause serious loss to the farming community." The 
 reply was that " there is no evidence that the firing 
 causes heavy rain," but this only meets belief with 
 denial. Though the argument is not strictly scientific, 
 perhaps the most convincing form of reply to those who 
 profess to believe, or do believe, in the efficacy of gun- 
 firing to produce rain, is to point out that the firing of 
 big guns is carried on at Shoeburyness more frequently 
 than at any other point on the coast, yet the mean 
 rainfall at Shoeburyness, and on the coast of Essex 
 generally, is the lowest in the British Isles. 
 
 It is commonly believed that during severe thunder- 
 storms a bolt is sometimes discharged from the clouds 
 and reaches the earth as a solid mass of stone or metal. 
 There is, however, not a particle of material evidence in 
 support of this belief. No thunderbolt originating in 
 the clouds has ever been found, and none exists, whatever 
 conviction may be held to the contrary. What are 
 mistaken for thunderbolts as popularly understood are 
 peculiar mineral objects, meteorites, or particles of soil 
 or rock which have been fused by lightning striking 
 the earth through them. 
 
 Masses of a metallic or stony nature do fall from the 
 sky occasionally, but they have nothing to do with 
 
112 DISCOVERY CH. 
 
 thunderstorms, and really reach the earth from outer 
 space. In its annual journey around the sun the earth 
 now and then encounters stray fragments of cosmic 
 matter, and draws them toward itself by the force of 
 gravitation. When the mass reaches the earth's atmos- 
 phere, friction against the air makes it white hot, and 
 like a moth flying into a flame it is consumed, the 
 streak of light thus produced being a shooting star or 
 meteor. Sometimes the piece of cosmic material is so 
 large that it is not completely consumed as it traverses 
 the atmosphere ; and in this case it reaches the earth 
 as a solid mass a meteorite which may weigh a few 
 ounces or several tons. Many of these meteorites are 
 preserved in our museums, but though they may make 
 a noise or a series of explosions as they hurl themselves 
 toward the earth, they are not connected in any way with 
 thunderstorms, and cannot correctly be termed thunder- 
 bolts. 
 
 Other objects often mistaken for thunderbolts are 
 known to geologists as fulgurites, and are produced by 
 the fusion of grains of loose sand by a lightning dis- 
 charge. At the mouth of the river Irt, in Cumberland, 
 fulgurites have been found extending to a depth of forty 
 feet in the sand, and a fulgurite found in a sandy stratum 
 at Macclesfield reached to a depth of twenty-two feet. 
 It is perhaps natural to conclude that tubes or patches 
 of fused rock, found after lightning has been seen to 
 strike the earth in a place where only loose sand could 
 be seen, actually came from the clouds, but here again 
 the view that " seeing is believing " leads to an erroneous 
 conclusion. 
 
 In the absence of any precise knowledge of the nature 
 of globular or ball lightning, it may be undesirable to 
 assert that nothing solid can come from a thunder- 
 
v BELIEF AND EVIDENCE 113 
 
 cloud ; nevertheless, it can be stated with confidence 
 that no so-called thunderbolt has ever proved to be 
 one, so that the possessor of a true specimen would 
 have an object of unique value and interest. In the 
 absence of such a specimen, it is permissible to state that 
 no thunderstorm has ever discharged a thunderbolt 
 which was afterwards picked up and is preserved in a 
 museum, or among a private collection of curiosities. 
 
 Uncritical observation and hasty conclusion are respon- 
 sible for the reports of the occur ence of living frogs 
 and toads enclosed in blocks of coal or other hard rock 
 many feet below the surface of the ground. A stone is 
 being broken by a quarryman, a frog is seen hopping 
 about close to the place, and forthwith the lively imagina- 
 tion of the labourer persuades him that he has seen it 
 actually come out of a cavity in the rock. Dean Buck- 
 land made experiments for the purpose of ascertaining 
 how long frogs and toads could live shut up in cavities 
 of stone and excluded from air and food, with the result 
 that most of them were dead within a year, and none 
 survived more than two years. Yet frogs are alleged 
 to have been found enclosed in rocks which, geology 
 teaches, were deposited under water millions of years 
 ago, and afterwards subjected to a pressure which has 
 crushed all the fossils contained in them as flat as paper. 
 If geology is right, the frog stories are utterly incredible. 
 Or, as a distinguished geologist once said, the blow of 
 the hammer that disclosed a live frog inside a block 
 of stone without an opening would at the same time 
 destroy not only geology but the whole fabric of natural 
 science. 
 
 Critical examination of evidence, and cautious con- 
 sideration of conclusions, are characteristic attributes of 
 a scientific mind. There is a tendency in the present 
 
 G.D, H 
 
114 DISCOVERY cm. 
 
 age to make sensational announcements upon a slender 
 basis of fact ; but science suffers by such premature 
 publication. Festina lente must be the motto if the 
 steps forward are never to be retraced. Test all things, 
 and you will then be in a position to hold fast by that 
 which is true. 
 
 When about the middle of the nineteenth century, 
 evidence was being found of man's existence upon the 
 earth for a period long anterior to the seven thousand 
 years or so of the Semitic tradition, it was regarded 
 with suspicion by men of science as well as the world in 
 general. M. Boucher de Perthes, antiquary, archaeo- 
 logist, and gentleman of France, announced in 1846 that 
 an ancient flint implement had been found associated 
 with bones of elephant, rhinoceros, and other extinct 
 animals in gravel exposed during excavations for the 
 construction of a canal at Abbeville. When three years 
 later he asserted that numbers of rudely worked and 
 chipped flint implements had been found with remains 
 of extinct mammals in the same undisturbed beds of 
 gravel, geologists gave no heed to his announcement, 
 and he was regarded as an amiable visionary. Dr. 
 Rigollot, of Amiens, appears to have been the only 
 naturalist in France who took the trouble to examine 
 the ground personally, with the result that he came 
 away convinced of the accuracy of M. de Perthes' 
 observations. The conclusions of both observers were 
 either scorned or discredited by the rest of their 
 countrymen for several years ; and it was an Englishman, 
 Joseph Prestwich, who ultimately proved them to be 
 correct. 
 
 Dr. Hugh Falconer saw M. de Perthes' collection of 
 flint implements, including a flint hatchet, in 1858 ; and 
 he wrote to Sir Joseph Prestwich asking him, as a 
 
v BELIEF AND EVIDENCE 115 
 
 geologist who would inquire into their origin and associa- 
 tions con amore, to take an early opportunity of visiting 
 Abbeville. Prestwich had made the gravels of England 
 the subject of particular study, and was, therefore, well 
 qualified to examine the proofs of the antiquity of man 
 yielded by similar deposits in France. It was said of 
 him, in mingled earnest and raillery, " point out a broken 
 pebble amongst a thousand others in a gravel pit, and 
 there is one who will tell you the point of the compass 
 from which it came, the stratum which yielded it, the 
 distance it had travelled, the amount of rolling it had 
 undergone, and the time it had occupied in its 
 journey." 
 
 Prestwich went to Abbeville and Amiens in 1859 and, 
 with Sir John Evans, examined both beds of gravel 
 and flint implements, with the result that he convinced 
 himself of the following facts : (1) that the flint imple- 
 ments are the work of man, (2) that they were found in 
 undisturbed ground, (3) that they are associated with 
 the remains of extinct mammals, (4) that the period 
 represented by the deposits containing the flint imple- 
 ments was late in geological time, and preceded that in 
 which the surface assumed its present outline. 
 
 In these conclusions we have definite statements of 
 fact in which no attempt is made to account for them 
 or consider their significance. It was certain that 
 primitive man existed in the north of France at the 
 same time as animals which had become extinct, for 
 his flint weapons were found associated with their bones. 
 Also, the old valley-gravels in which the relics occurred 
 must have been deposited before the ground took its 
 present configuration ; that is, long before historic 
 times. Whether the gravels with their flint implements 
 and other remains represented an epoch thousands or 
 
116 DISCOVERY OH. 
 
 tens of thousands of years ago could not then be decided, 
 but in any case the period was long anterior to that 
 in which man was supposed to have been created. 
 
 The importance of these discoveries was readily 
 recognised by geologists ; but such revolutionary views 
 as to the remote antiquity of man naturally met with 
 much opposition from the guardians of traditional 
 teaching. Prestwich was a devout Churchman, and he 
 cautiously abstained from making any pronouncement 
 upon the necessity of extending current chronological 
 ideas as to the existence of man, but he could not be 
 false to the facts before him, and the truths which they 
 revealed have since been placed beyond criticism. 
 Geologists have now no hesitation in stating that it 
 must have been at least ten thousand years ago since 
 man the hunter made the flint implements found mingled 
 with the remains of various animals in the valley- 
 gravels of Abbeville and elsewhere. 
 
 It is to Prestwich more than to any other geologist that we 
 owe the establishment of the fact that man co-existed with a 
 number of now long extinct mammals, and that his advent on 
 the earth must be relegated to a far higher antiquity than that 
 which had previously been accepted. Sir Archibald Oeikie. 
 
 We have described these observations and conclusions 
 somewhat fully because of the excellent example they 
 afford of the difference between belief and evidence. 
 No one now supposes that only a few thousand years 
 have elapsed since man made his appearance upon the 
 earth, yet that was the belief until accurate observation, 
 cautiously interpreted, proved it to be untenable. It is 
 not surprising that facts which led to such revolutionary 
 ideas as to man's antiquity should have had almost 
 to force their way to attention. Until scientific obser- 
 vation had provided incontrovertible evidence of th 
 
 
v BELIEF AND EVIDENCE 117 
 
 existence of prehistoric man in an early stage of culture, 
 it was easy to believe anything as to human origins. 
 
 It was the absence of methods of accurate observation 
 and critical inquiry, and the subservience of mind to 
 authority, that led to many fables and beliefs being 
 handed down as natural truths for hundreds of years. 
 Among such beliefs mentioned by Prof. L. C. Miall in 
 his Early Naturalists are : that the crocodile weeps 
 when it has eaten a man ; that the hedgehog sticks ripe 
 grapes upon its prickles, and so carries them home to its 
 children ; that the crab waits till the oyster gapes and 
 then puts a stone between the shells, so that he may 
 gnaw the oyster's flesh ; that an oar dipped into water 
 seems to be broken because of the swift moving of the 
 water ; that the chameleon feeds on air ; that during 
 the winter swallows lie hidden at the bottom of lakes 
 and rivers, two together, mouth to mouth, and wing to 
 wing ; that buried crabs produce scorpions ; that the 
 hind legs of the frog are formed by the splitting of the 
 legs of the tadpole ; that barnacles are transformed 
 into geese, goats are milked by the nightjar, and that 
 gryphons, harpies, phoenixes, rocs, and like legendary 
 creatures actually exist. 
 
 Most of these beliefs probably had their origins in the 
 casual observation and hasty conclusion which are anti- 
 thetic to scientific methods of inquiry and thought. The 
 literature of the ancients is full of fabulous statements 
 and misinterpretations of natural things ; and many of 
 the paradoxes and fallacies contained in it persist to the 
 present day. 
 
 The belief that when a horsehair is left in a stream or 
 lake for a little while it assumes life, and finally becomes 
 an eel, is an instance of an error due to superficial 
 observation. There is a species of thread-worm which 
 
118 DISCOVERY OH. 
 
 develops in stagnant pools and somewhat resembles a 
 horsehair in appearance, and as a dry horsehair when 
 placed in water may twist about somewhat in the fashion 
 of this parasite, one was supposed to be produced from 
 the other, after which the transition from the thread- 
 worm to the eel became easy to a credulous mind. This 
 simple way of explaining the origin and development of 
 the common eel satisfied the uncritical observer, but 
 the truth was much more difficult to discover. 
 
 From the days of Aristotle onward the actual mode 
 of development of the eel was a mystery. It was 
 known that large eels pass from rivers into the sea at 
 certain seasons, and that diminutive young eels, called 
 in this country elvers, ascend the rivers in enormous 
 numbers. But until Profs. Grassi and Calandruccio, 
 of Rome, investigated the matter in 1895, no one in 
 any country had been able to discover how the elvers 
 were produced. These naturalists proved that the eels 
 which annually descend the rivers travel very long 
 distances, until they reach the ocean. It is not known 
 exactly in what part of the ocean spawning takes place, 
 but the eggs develop into strange, colourless, trans- 
 parent, thin-bodied creatures, which were thought to 
 be a special family of fishes, but are now known to be 
 really the larvae of eels. After attaining a certain size 
 the larva ceases to feed, its body shrinks, and it assumes 
 the very different form of the elver which ascends our 
 rivers. A more wonderful series of changes than that 
 thus revealed would be difficult to find. The whole 
 story of the eel and its spawning reads almost like a 
 romance instead of scientific reality. 
 
 Another curious case of deceptive appearance gave 
 rise to the widespread belief in the production of honey 
 by bees in the carcasses of dead animals, and principally 
 
v BELIEF AND EVIDENCE 119 
 
 from those of oxen, whence the term Bugonia oxen- 
 born used in Greece to describe it. Vergil referred to 
 the legend in his Fourth Georgic, but the earliest appear- 
 ance of the belief in literature is found in the Biblical 
 story of Samson, who had killed a lion in the vineyards 
 of Timnath on his way to his bride : " And after a time 
 he returned to take her, and he turned aside to see the 
 carcass of the lion ; and behold there was a swarm of 
 bees and honey in the carcass of the lion." The story 
 leads up to the riddle propounded by Samson : " Out of 
 the eater came forth meat, and out of the strong came 
 forth sweetness." 
 
 Many professors of scriptural exegesis have commented 
 upon these passages, and offered explanations of the 
 appearance of the cleanly hive- bees in the carcass of a 
 lion. Linnaeus once said that the progeny of three 
 blow-flies would devour the carcass of an ox as quicky 
 as would a lion ; and on this principle, commentators 
 who insist upon literal interpretations have concluded 
 that " after a time " may mean a sufficient interval for 
 the carcass to be reduced to a clean skeleton and the 
 bees to have made a hive in it. We are not concerned 
 here, however, with exegetic difficulties, but with the 
 fact that the belief in the Bugonia legend was current 
 among the people of Samson's time. 
 
 So far back as the latter half of the seventeenth 
 century, Swammerdam suggested that the insects 
 supposed to be bees in a decaying carcass were really 
 flies which resembled bees, but his desire for a literary 
 interpretation of a scriptural passage prevented him from 
 taking the last step that was needed. Keaumur, the 
 French naturalist, showed clearly in 1738 the resem- 
 blance between the drone-fly and the honey-bee, and 
 remarked : " such resemblances have made people 
 
120 DISCOVERY OH. 
 
 believe that honey-bees, hornets and wasps originate 
 in putrescent matter upon which those other flies 
 occur." 
 
 Towards the end of the nineteenth century, Baron 
 Osten Sacken proved that the Bugonia fable had its 
 origin in the fact that the drone-fly lays its eggs upon 
 carcasses of animals, that its maggots develop within 
 the putrescent mass and resemble bee-larvae, and 
 finally change into a swarm of flies which, in their shape, 
 hairy covering and colour, look exactly like bees, 
 although they belong to a totally different order of 
 insects. " Thinking is difficult, and acting according 
 to reason is irksome," said Goethe. For more than 
 two thousand years people overlooked the likeness 
 between the drone-fly and the honey-bee, and believed 
 in a tradition which a single experiment would have 
 shown to be without the slightest foundation. 
 
 We may forgive most people for holding such beliefs, 
 because they may have had no easy opportunity of 
 testing them by personal observation ; but it is remark- 
 able that writers on natural history should be content 
 to hand down statements of traditional authorities 
 without troubling to look for evidence of the beliefs 
 they accepted, or to examine for themselves the com- 
 monest natural facts. Perhaps the most extraordinary 
 case of this mental blindness is that of the colours of 
 the rainbow. In De Proprietatibus Rerum, written by 
 Bartholomew of England before the middle of the 
 thirteenth century, and translated into English in 1397, 
 the succession of colours in the rainbow is given as red, 
 blue and green. " This succession," says Prof. Miall, 
 " had a mystical meaning ; red was a symbol of fire, 
 blue of water, green of earth. For more than five 
 hundred years men went on repeating an error which 
 
v BELIEF AND EVIDENCE 121 
 
 might have been corrected at once by observation of 
 an actual rainbow." 
 
 Misconception as to the cause and character of many 
 common phenomena in Nature ; the tendency to accept 
 statements without inquiry into the credentials of the 
 author or independent investigation of the facts ; and 
 the view that science is an esoteric study beyond the 
 comprehension of most people, are almost as prevalent 
 now as they were in former times. The book of Nature 
 is open for all to read, yet few look into it and fewer try 
 to understand what is written. 
 
 The sun rises and sets at different points on the 
 horizon every day, yet it is believed by the unobservant 
 to rise in the east and set in the west throughout the 
 year ; the starry heavens may be seen majestically 
 swinging around a point near the North Star every fine 
 night, but this apparent movement has escaped general 
 notice ; the horns of the new or old crescent moon 
 always point away from the sun, yet artists continually 
 paint the moon in unnatural positions at sunrise and 
 sunset ; rising and setting new or old moons are described 
 at impossible times by authors who ought to know better ; 
 the centre of a rainbow is always opposite the sun, and 
 there is always a regular succession of colours from red 
 to deep blue, the red being on the outside of the arc and 
 the blue inside in the case of a single rainbow, and in the 
 reverse order in the additional or secondary bow some- 
 times seen ; yet the colours are often wrongly described 
 or depicted, and a halo seen when facing the sun is mis- 
 taken for a rainbow, which can only be seen when the 
 observer has his back to the sun. 
 
 Hasty conclusions are responsible for many mistaken 
 interpretations of natural incidents, even when pheno- 
 mena have been accurately observed. Before the days 
 
122 DISCOVERY OH. 
 
 of Copernicus, nothing seemed more obvious than that 
 the sun actually moved round the earth every day ; for 
 " seeing is believing " was considered as cogent an 
 argument then as it is now. But every one knows in 
 these days that the conclusion was incorrect, and that 
 the apparent daily motion of the sun is an effect produced 
 by the real motion of the earth upon its axis, the sun 
 being practically a fixed body as regards the earth. To 
 inhabitants of the northern hemisphere, unfamiliar 
 with the cause of the seasons, it is perhaps natural to 
 conclude that the earth is nearer the sun in the northern 
 summer than in winter, whereas the earth is three 
 million miles nearer the sun at the beginning of January 
 than it is at the beginning of July. 
 
 Most of these facts are known to all observant people, 
 but judging from statements commonly made in news- 
 papers not only in daily papers but also in weekly 
 periodicals in which greater accuracy might reasonably 
 be expected there are few literary people who have a 
 knowledge of natural objects and phenomena equivalent 
 to that of children in the State schools. It is scarcely 
 too much to say that, omitting signed articles written 
 by experts, few newspapers make any announcement 
 relating to a scientific subject without committing a 
 mistake. Either terms are wrongly used, or a matter 
 of common knowledge among men of science is 
 regarded as a remarkable discovery, or observations of 
 a sensational kind are presented to the public as if they 
 were established truths, though they await confirmation 
 from the scientific world, and are mostly unworthy of 
 serious consideration. 
 
 Almost every newspaper report of a volcanic eruption 
 contains a reference to " flames and smoke " issuing 
 from " the burning mountain," though this description 
 
v BELIEF AND EVIDENCE 123 
 
 of the phenomena is completely inaccurate. During an 
 eruption there is practically no flame, and certainly 
 none that can be seen except close to the crater ; no 
 smoke such as issues from a chimney is ever produced ; 
 and there is no burning in the ordinary sense of com- 
 bustion as in a fire. These elementary facts have been 
 taught to thousands of school children for the past 
 twenty years, yet popular writers and journalists seem 
 still to be unaware of them. 
 
 A volcanic eruption may be compared not inaptly to 
 a series of boiler explosions. The dense clouds projected 
 from the vents at each paroxysm of the eruption consist 
 of steam and fine dust, and the light of the molten rock 
 in the crater flowing down the flanks of the volcano 
 as lava streams, illuminates the clouds so brilliantly as 
 to give the appearance of flames. As the lava flows it 
 also emits water vapour copiously and seems to burn 
 and smoke, though what looks like smoke is really 
 steam, and the flame is reflected light. Whatever may 
 be the ultimate cause of volcanic action, the sudden 
 transformation of water into vapour is the active agent 
 of an eruption, and by far the most abundant product 
 ejected is steam. A few inflammable gases are pro- 
 duced, and as they burn they give rise to true volcanic 
 flames, but their pale and flickering light cannot easily 
 be distinguished when a volcano is in active eruption. 
 
 It may be too much to expect men of letters to 
 possess an elementary knowledge of science, or to have 
 any sympathy with scientific precision, but it is not 
 unreasonable to ask for accuracy of description when 
 they are dealing with natural facts and phenomena. 
 They may reply that Shakespeare was often at fault in 
 matters pertaining to natural history ; but he at any 
 rate reflected in his works the best knowledge of his 
 
124 DISCOVERY OH. v 
 
 time, which is more than can be said of most writers 
 to-day. 
 
 We are often told that men of science should culti- 
 vate the art of literary expression, but the stronger 
 necessity for literary men to have at least a nodding 
 acquaintance with the outstanding facts of natural 
 knowledge is overlooked. A well-known author has 
 unkindly said, " The man of science appears to be the 
 only man in the world who has something to say, and 
 he is the only man who does not know how to say it." 
 The retort invited by this remark is that the man of 
 letters frequently has nothing to say, and he says it at 
 great length. The first business of the man of science is 
 to create new knowledge, and not necessarily to clothe 
 his discoveries in a pleasing dress, though he may do so. 
 The facts of science provide material upon which literary 
 art may be exercised, but the two functions of exploration 
 and fine expression are rarely found together. 
 
 The methods of accurate observation and cautious 
 interpretation demanded of scientific investigators do 
 not readily lend themselves to attractive description, 
 and the results require more mental concentration to 
 understand them than is usually demanded of a literary 
 performance. A writer of romance can let his imagina- 
 tion have free play, but when natural occurrences enter 
 into the story they should be presented accurately, if the 
 material is to be used rightly. Nothing is easier than 
 to be deceived by appearances, or to accept a belief 
 without inquiry into its foundations ; the scientific plan 
 of asking for evidence, and of limiting statements to 
 those for which good justification can be produced, is 
 much more tiresome, yet it is the only way by which 
 truth can be attained ; and that after all is the highest 
 aim. 
 
CHAPTEE VI 
 INQUIRY AND INTERPRETATION 
 
 Science commits suicide when it adopts a creed. Huxley. 
 
 The philosophy of one century is the common-sense of the 
 next. H. W. Beecher. 
 
 Forgetting those things which are behind, and reaching 
 forth unto those things which are before. St. Paul. 
 
 For nothing is so productive of elevation of mind as to be 
 able to examine methodically and truly every object 
 which is presented to thee in life. Marcus Aurelius. 
 
 The patient investigation and accurate methods required to 
 obtain desired results in the school of experimental and 
 technical science, cannot fail to impress, refine, and 
 ennoble the characters of those who work in this direction. 
 Sir Wm. Mather. 
 
 MANY people find satisfaction in the words of the 
 preacher " there is no new thing under the sun " ; they 
 delight in tracing suggestions of modern scientific 
 discoveries in the works of Greek, Roman and other 
 philosophers, and in showing that classical literature 
 contains all that is required for the making of a good 
 citizen or for intellectual equipment. Well, in regard 
 to logic, mathematics, metaphysical philosophy, juris- 
 prudence, or any subject in which words or symbols 
 make up the mosaic, and in ethical teaching, humanists 
 are possibly right in attaching supreme importance 
 to the thoughts and doctrines of other times. In 
 observation also, and to some extent in mechanical 
 
126 DISCOVERY OH. 
 
 ingenuity, the works of many of the ancients command 
 the esteem of the modern scientific world. What is 
 peculiarly modern is the experimental investigation of 
 natural phenomena ; and the looking for mere rules of 
 sequence in the phenomena rather than transcendental 
 causes is of still more recent growth. 
 
 The art of observation and that of experimentation are very 
 distinct. In the first case, the fact may either proceed from 
 logical reasons or be mere good fortune ; it is sufficient to have 
 some penetration and the sense of truth in order to profit by it. 
 But the art of experimentation leads from the first to the last 
 link of the chain, without hesitation and without a blank, making 
 successive use of Reason, which suggests an alternative, and of 
 Experience, which decides on it, until, starting from a faint 
 glimmer, the full blaze of light is reached. J. B. A. Dumas. 
 
 The merit of scientific observation lies in the direct 
 appeal to Nature for truth instead of to authority. 
 Whenever man has seen things for himself, and has not 
 been content with vicarious observation, he has taken a 
 decided step towards the emancipation of the human 
 race from the trammels of traditional doctrine. But 
 modern science demands something more than an open 
 eye for its advancement ; it requires the kinetic quality 
 of mind that tests by experiment the things which might 
 be, as well as observes things as they are. 
 
 The method which our race has found most effective in acquir- 
 ing knowledge is by this time familiar to all men. It is the method 
 of modern science that process which consists in an interroga- 
 tion of Nature entirely dispassionate, patient, systematic ; such 
 careful experiment and cumulative record as can often elicit 
 from her slightest indications her deepest truths. That method 
 is now dominant throughout the civilised world ; and although 
 in many directions experiments may be difficult and dubious, 
 facts rare and elusive, science works slowly on and bides her 
 time refusing to fall back upon tradition or to launch into 
 speculation merely because strait is the gate which leads to 
 valid discovery, indisputable truth. F. W. H. Myers. 
 
vi INQUIRY AND INTERPRETATION 127 
 
 Scientific observations of natural phenomena were 
 recorded four thousand years or more ago, but recogni- 
 tion of the essential importance of experimental science 
 of the modern type is only about three centuries old, 
 though the method was adumbrated at an earlier epoch. 
 
 As an observer and a recorder Aristotle surveyed the 
 whole realm of Nature in his works, and had familiar 
 knowledge of a thousand varied forms of life. He 
 brought together an immense amount of accurate 
 observation and examined it with skilful reasoning, but 
 he was often led astray by pre-conceived ideas, and 
 based his conclusions upon reports which were more 
 curious than important. But he and other ancient 
 philosophers particularly lacked the scientific method of 
 inquiry by experiment. It is true that Pythagoras, in 
 the sixth century B.C., is credited with the use of mono- 
 chord, or single stretched string, of which the length and 
 tension can be varied, to determine by experiments the 
 law that the pitch of a note is inversely proportional to 
 the length of the vibrating string, and to discover 
 numerical relations between the various notes on the 
 musical scale. It is also true that Ptolemy, in the second 
 century A.D., determined by experiment the refraction 
 or amount of deviation which a beam of light undergoes, 
 from its original direction, when passing from air into 
 water, or into glass. But these determinations, with the 
 work in acoustics by Pythagoras, and Galen's proofs, by 
 the dissections of animals, of the relation between the 
 brain and the nerves, represent the sum total of experi- 
 mental research in Greek science. 
 
 There was an interval of a thousand years between 
 Ptolemy's investigations in optics and the experiments 
 made by Alhazen, whose substantial studies of reflection, 
 refraction, vision, the human eye and related subjects 
 
128 DISCOVERY OH. 
 
 are the outstanding contributions of Arabia to physical 
 science in a period during which the Arabs were in 
 advance of the whole world in intellectual and industrial 
 activity. It was chiefly upon the researches of Alhazen 
 that Roger Bacon based the principles of optics 
 expounded .by him. This Franciscan Friar of the thir- 
 teenth century anticipated many later discoveries in 
 physics and chemistry, and though he did not actually 
 discover the telescope, he described in detail, in his Opus 
 Majus (1276), the properties of lenses and how they could 
 be used to make objects appear nearer, as in the case of 
 a simple magnifying glass. 
 
 Adelard of Bath, who translated Euclid's Elements of 
 Geometry from Arabic into Latin early in the twelfth 
 century four hundred years before the Greek text was 
 recovered ; Robert Grosseteste, the illustrious Bishop 
 of Lincoln and author of an encyclopaedic Compendium 
 Scientiarum ; Peter Peregrinus of Maricourt, of whom 
 Bacon said : " Through experiment he gains knowledge 
 of natural things, medical, chemical, indeed of everything 
 in the heavens or earth," all preceded Bacon in their 
 scientific observations and writings and influenced his 
 thought. He was not really a great experimenter, and 
 his positive additions to natural knowledge are few, but 
 he was one of the first philosophers to insist upon the 
 value of experiment in scientific investigation. " We 
 have," he said, " three means of knowledge authority, 
 reasoning, experiment. Authority has no value unless 
 its reason be shown ; it does not teach : it only calls for 
 assent." Again " Armed with experiment and calcula- 
 tion, science must not be content with facts, though these 
 may have their utility ; it seeks truth ; it wants to find 
 out the laws, the causes canones, univer sales regulae." 
 
 In the bold appeal which Roger Bacon made to experi- 
 
vi INQUIRY AND INTERPRETATION 129 
 
 ment and the observation of Nature, he stood out as 
 the champion of unfettered inquiry in a period of 
 scientific stagnation, and he suffered persecution, banish- 
 ment and imprisonment for his temerity. In popular 
 esteem the memory of this champion of experimental 
 science and advocate of positive knowledge has always 
 been cherished ; and after seven hundred years, in 1914, 
 Oxford commemorated the birth of this one of her great- 
 est sons described by Humboldt as " the greatest ap- 
 parition of the Middle Ages," by erecting a statue to him. 
 Two hundred years after Roger Bacon, appeared that 
 prodigy of Nature, Leonardo da Vinci (1452-1519), 
 whose curiosity was insatiable, and whose methods were 
 to search out all things, to experiment and verify, to 
 let his eyes test and his reason judge. Another Italian 
 philosopher who saw that the appeal should be from 
 authority to Nature and urged that all true knowledge 
 came from data given by the senses, was Bernardino 
 Telesio (1509-1588). Leonardo himself had the clearest 
 ideas as to the scientific method of inquiry. 
 
 In treating any particular subject I would first of all make 
 some experiments, because my design is first to refer to experi- 
 ments and then to demonstrate why bodies are constrained to 
 act in such a manner. This is the method we ought to follow 
 in investigating the phenomena of Nature. Theory is the general, 
 experiments are the soldiers. Experiment is the interpreter of 
 the artifices of Nature. It is never wrong ; but our judgment 
 is sometimes deceived because we are expecting results which 
 experiment refuses to give. We must consult experiment and 
 vary the circumstances, till we have deduced general laws, for 
 it alone can furnish us with them. Leonardo da Vinci. 
 
 Leonardo was by profession an engineer, but he 
 was also sculptor, musician and poet, and his fresco 
 representing the Last Supper places him among the 
 most illustrious artists of the world. He investigated 
 
 G.D. I 
 
130 DISCOVERY CH. 
 
 thoroughly the laws relating to the movement of water 
 and hydraulics generally, and anticipated many of the 
 theories for which credit is often given to men of science 
 who lived many years after him. Hallam, in his Intro- 
 duction to the Literature of Europe, says that the 
 discoveries which made the names of Galileo, Kepler 
 and others famous, the system of Copernicus, and the 
 theories of modern geologists, were anticipated by 
 Leonardo within the compass of a few pages ; not 
 perhaps in the most precise language, or in the most 
 conclusive reasoning, but so as to strike us with some- 
 thing like the awe of preternatural knowledge. In his 
 work as an engineer he followed truly scientific methods. 
 " Those," he said, " who are infatuated by practice 
 without science, are like the navigator who sails a ship 
 without helm and compass ; he never knows with 
 certainty whither he goes. Practice must always be 
 built upon theory. Study science first, then follow the 
 practice which is born of science." 
 
 Bernard Palissy, the potter who sacrificed everything, 
 even the furniture of his cottage, in the production of a 
 glaze for earthenware, was also one of the earliest 
 followers of the experimental method of studying other 
 aspects of Nature. His life extended over nearly the 
 whole of the sixteenth century, and his contributions 
 to agriculture, chemistry, mineralogy and geology dis- 
 turbed the schoolmen and provided a new foundation 
 for science. He was the first to give a true explana- 
 tion of the origin of springs, and like Leonardo da 
 Vinci, he understood that fossils represented past 
 forms of life and were not freaks of Nature or relics of 
 the world before Noah's flood. Buffon said of him, 
 about a century and a half later, " a simple potter of 
 the end of the sixteenth century was the first to dare, 
 
vi INQUIRY AND INTERPRETATION 131 
 
 to tell Paris and the doctors that marine fossils were 
 true animal remains, were deposited in a sea in the 
 place where they are now found, and were born of their 
 respective animal parents. This he defied the Aris- 
 totelians to deny." 
 
 Palissy offended the alchemists and astrologers of his 
 time, as well as the priests and philosophers, by his 
 ridicule of cherished opinion regarding natural objects 
 and phenomena ; and he died in prison in consequence 
 of his appeal to observation and experiment for the basis 
 of every speculation. He was an apostle of the inductive 
 method, and demonstrated its application to large 
 audiences in Paris, during the three years which Francis 
 Bacon spent there in his youth ; it has indeed been 
 suggested .by Sir Clifford Allbutt that Bacon first 
 derived his ideas of inductive philosophy from the 
 collections and contentions of Palissy, whose observa- 
 tions and influence are, however, rarely mentioned in 
 the history of scientific thought. 
 
 Dr. William Gilbert (1540-1603), of Colchester, known 
 to most students of magnetism and electricity as the 
 founder of these branches of science, also practised the 
 experimental method of investigation before Francis 
 Bacon wrote about it. He is, indeed, repeatedly men- 
 tioned by Bacon in the Novum Organum, and elsewhere 
 he is praised both for his industry and his method, 
 but censured for endeavouring to build a universal 
 philosophy upon a narrow basis ; and not without 
 reason. Gilbert was largely indebted in his work on 
 magnetism to the observations of Peter Peregrinus made 
 three centuries earlier, and he was so dominated by the 
 notion that magnets possessed some sort of soul or 
 spirit that he should perhaps be considered as a sort of 
 connecting link between medieval superstitions and the 
 
132 DISCOVERY CH. 
 
 modern spirit. He did, however, make better use of 
 the experimental method than any natural philosopher 
 who preceded him, and his work did much to break down 
 the barrier raised by traditional belief against indepen- 
 dent investigation. 
 
 In the discovery of secrets, and in the investigation of the 
 hidden causes of things, clear proofs are afforded by trustworthy 
 experiments rather than by probable guesses and opinions of 
 ordinary professors and philosophers . . . To you alone, honest 
 and true men of science, who seek knowledge, not from books 
 only, but also from things themselves, do I address these magnetic 
 principles and this new sort of philosophy. If any disagree 
 with my opinion, let them at least take note of the experiments 
 and discoveries which have been worked out and demonstrated 
 by me, with many pains and vigils and expenses. Let them 
 rejoice in these, and employ them to better use if they are able. 
 W . Gilbert. 
 
 The ancients used only two methods of investigation 
 the philosophical and the mathematical ; the third 
 method, by experiment, was put into deliberate practice 
 by Palissy, Gilbert and Galileo. By offering experi- 
 mental evidence against what was believed to be the 
 teachings of Aristotle, Galileo established the modern 
 experimental method of inquiry in Nature. The 
 authority of Aristotle as the arch-priest of natural 
 science had been questioned before the time of Galileo, 
 but no attempt had been made to confound it with truths 
 secured by direct appeal to Nature. The high regard in 
 which Galileo held the facts obtained by experiment, in 
 comparison with the conclusions of peripatetic philo- 
 sophy, is reflected in a letter written by him in 1615 : 
 
 I would entreat these wise and prudent fathers to consider 
 diligently the difference between opinionative and demonstrative 
 doctrines, to the end that they may assure themselves that it 
 is not in the power of professors of demonstrative sciences to 
 change their opinions at pleasure. Galileo* 
 
vi INQUIRY AND INTERPRETATION 133 
 
 Francis Bacon is sometimes called the Father of 
 Experimental Philosophy, but it may be doubted 
 whether he merits the title ; indeed, he disregarded 
 in his own works the very principles of scientific inves- 
 tigation expounded by them. What Bacon did was to 
 form into a system the method of investigation which 
 consists in asking questions of Nature herself, of making 
 observations with great care, carefully arranging them, 
 and cautiously arriving at conclusions from them. 
 Aristotle had long before insisted upon the collection 
 of facts, and urged that we must " first classify them, 
 bring particular facts under general heads and co- 
 ordinate them into theories." He collected so-called 
 " facts " by hundreds, and proceeded to speculate upon 
 them as if they were unalterable truths, whereas in many 
 cases they were merely old women's tales or other 
 hearsay evidence. His method was a logical machine 
 which could produce reasonable results when provided 
 with sound material to work upon, but not otherwise. 
 Aristotle and the school of thought he dominated for 
 nearly two thousand years, knew nothing of the experi- 
 mental method of inquiry ; and by proclaiming that 
 " our only hope is in the regeneration of the sciences 
 by regularly raising them on the foundation of experi- 
 ence " Bacon became the apostle of a new school of 
 philosophy, though not the founder of it. 
 
 Bacon's influence in establishing this inductive 
 process of inquiry is often over-estimated, and he 
 owes his prominence to the fact that his works 
 appeared at the right psychological moment, when 
 the age was ripe to receive a new philosophy. As 
 we have seen, three centuries before the time of 
 Francis Bacon, the main doctrines he promulgated 
 had been proclaimed by Roger Bacon, and not only 
 
134 DISCOVERY OH. 
 
 announced as articles of scientific belief but also 
 followed in practice. 
 
 It is clear, therefore, that modern methods of obser- 
 vational and experimental science were not founded by 
 the works of Francis Bacon. Before his day, Tycho 
 Brahe had gone to the heavens for his astronomical 
 facts instead of to Greek philosophy, and had earnestly 
 urged his pupil Kepler " to lay a solid foundation for 
 his views by actual observation, and then by ascending 
 from these to strive to reach the causes of things." 
 Leonardo da Vinci had advanced science and engineering 
 in many directions ; and Palissy had collected and 
 studied a large variety of natural things. Gilbert had 
 made his memorable experimental researches on mag- 
 netism, while Galileo had confounded orthodox philo- 
 sophy by his investigations in mechanics and observations 
 of celestial objects. 
 
 Bacon drew up the rules by which he considered 
 Nature should be studied, but he treated almost with 
 contempt all progress accomplished without the use of 
 his prescription, and he persistently rejected the Coper- 
 nican theory, though it formed the best possible example 
 of the application of his own system of collecting obser- 
 vations and arriving at conclusions from them. Few 
 natural philosophers who came after him took heed of his 
 artificial process of discovery ; and there is little evidence 
 that the method assisted in the advance of science 
 in any way. Newton never mentioned Bacon or his 
 system, though he was born and educated after its 
 publication ; and a study of the progress of science fails 
 to furnish sufficient reason for believing that Bacon's 
 Novwn Organum has been either a powerful source of 
 inspiration or has provided the formula by which natural 
 knowledge has been increased. 
 
vi INQUIRY AND INTERPRETATION 135 
 
 It is, indeed, a mistake to suppose that all scientific 
 investigation must proceed from the general to the parti- 
 cular according to a prescribed formula, or be determined 
 by any like hard-and-fast principle. Devotion to such 
 doctrines has often led men astray and is always an 
 undesirable obsession. 
 
 The maxim which should guide us in our work is not from the 
 simple to the complex, nor yet, as some philosophers have taught, 
 from the more needful to the less needful, but from the known to 
 the unknown, from truths either discovered by steady effort or 
 stumbled on by accident to new truths springing out of past 
 acquisitions, and verified by observation or experiment. Biolo T 
 gists, like other scientific discoverers, have a rugged peak to climb, 
 and are often urged to try this or that infallible method of Bacon, 
 Descartes, or Comte, a method which generally turns out to be 
 either misleading or impracticable. There is but one way to 
 wriggle up as you can, sometimes taking to the right, sometimes 
 to the left, sometimes turning back, because what looked like a 
 promising opening proves to lead nowhere. It is a great thing 
 to possess natural aptitude for the work, a great thing too to be 
 obstinately bent on getting to the top, but the successful climber 
 often owes much to good-luck wisely turned to account. Prof. 
 L. C. Miall. 
 
 In his New Atlantis, Francis Bacon planned in some- 
 what fanciful language a palace of invention, a great 
 temple of science, where the pursuit of knowledge in 
 all its branches was to be organised on principles of the 
 highest efficiency. He argued that for a nation to 
 apply a substantial part of its material resources to the 
 equipment of scientific work and exploration, a share 
 of its resources which should grow greater with the 
 growth of population and the increasing complexity of 
 knowledge, was the surest guarantee of national glory and 
 prosperity. We still await in the United Kingdom the 
 realisation of this institution. The Royal Society of 
 London, which was founded for the furtherance of the 
 
136 DISCOVERY CH. 
 
 experimental philosophy which Bacon wished to see 
 pursued, had no endowment from King or country, and 
 even now the subvention which it receives annually from 
 the State for its own requirements amounts to only a 
 thousand pounds towards the cost of scientific publica- 
 tions, together with the use of its rooms at Burlington 
 House. 
 
 The experimental method of research represented the 
 spirit in which the Royal Society was founded and became 
 an organised association with a Royal Charter in 1662. 
 No subject was considered too trivial for study by 
 observation and experiment ; and advantage was taken 
 of every opportunity of advancing knowledge. Among 
 the subjects brought forward at one of the earliest 
 meetings of the Society were : 
 
 Experiments with wires of severall matters of ye same size, 
 silver, copper, iron, &c., to see what weight will breake them. 
 Experiment concerning the force that presseth the aire into 
 lesse dimensions ; and it was found that twelve ounces did 
 contract 1/24 part of Aire. Experiment to show how much 
 aire a man's lungs may hold, by sucking up water into a separating 
 glasse after the lungs have been well emptied of Aire. Experi- 
 ment of Animal engrafting, and in particular of making a Cock 
 spur grow on a Cock's head. Whether there bee any such thing 
 as sexes in trees and other plants ; some instances were brought 
 of Palme trees, plum trees, hollies, Ash trees, Quinces, pionies, 
 &c., wherein a difference was said to be found, either in there 
 bearing of fruit or in their hardness and softness, or in medical 
 operations. 
 
 At that time and later some of the foremost men of 
 letters exercised their powers of wit and ridicule and 
 sarcasm upon the men who were devoting their time 
 to the patient investigation of Nature. None of the 
 common people, and few of the writers and scholars, 
 could understand why valuable time should be given 
 up to the study of " beasts, fishes, birds, snails, 
 
vi INQUIRY AND INTERPRETATION 137 
 
 caterpillars, flies," and as to making experiments on the 
 weight of air, even Charles II., who took great interest 
 in the Society, is said by Pepys to have " mightily 
 laughed at Gresham College, for spending time only in 
 the weighing of ayre, and doing nothing else since they 
 sat." 
 
 From the time of Galen (130-200 A.D.), the first 
 physiologist and the last of the Greek physicians, to 
 that of William Harvey (1578-1657), knowledge of the 
 human body made practically no progress. Dialectic 
 and dogma, mysticism and tradition, dominated the 
 science of medicine, and physicians lived fifteen centuries 
 on the capital accumulated for them by one who went 
 to Nature for his facts. 
 
 By the dissection of animals, Galen proved that the 
 brain is the centre of sensation and receives its messages 
 through the nerves. His authority and that of Aristotle 
 were considered sufficient for all time upon every 
 question relating to the human organism ; and the results 
 of the experimental work of Harvey in the seventeenth 
 century were opposed by dogma derived from the work 
 of an investigator on the other side of the bridge which 
 spanned the intervening gulf of fifteen centuries of 
 bankruptcy of medical science. 
 
 Harvey takes a place with Gilbert and Galileo as an 
 experimental philosopher and an apostle of the scientific 
 method. He observed things for himself, experimented 
 in order to see Nature at work, and did not let the views 
 of Galen or Aristotle influence his conclusions. " I 
 sought to discover," he says, " the motions and uses 
 of the heart from actual inspection and not from the 
 writings of others ; at length, and by using greater and 
 daily diligence and investigation, making frequent 
 inspection of many and various animals, and collating 
 
DISCOVERY CH. 
 
 numerous observations, I thought I had attained to 
 the truth." 
 
 For nine successive years Harvey expounded his 
 views on the circulation of the blood, and demonstrated 
 the anatomical and experimental evidence on which his 
 conclusions were based, in his lectures at the Royal 
 College of Physicians. Only after this probationary 
 period, did he give his discoveries to the world in a 
 little book of 76 pages, published in 1628, on the 
 Movements of the Heart and of the Blood. In this 
 treatise Harvey established absolutely the fact of the 
 circulation of the blood, and the fact that muscular 
 action of the heart causes this movement. But he was 
 unable, from his want of a microscope, to indicate the 
 precise path along which the blood travels from the 
 terminal arteries to the commencing veins. 
 
 The large artery from the heart gives off branches to 
 various parts of the body, and these branch off again into 
 small arteries in different organs. Similarly, small 
 veins carrying blood back to the heart unite to form 
 large veins. How the blood passed from the small 
 arteries to the small veins could only be conjectured by 
 Harvey, and was not discovered until three years after 
 his death. He concluded that the blood passes from 
 the arteries to the veins mainly by percolation, as water, 
 to use his own illustration, percolates the earth and 
 produces springs and rivulets. No microscope in his 
 time was powerful enough to enable him to see the 
 meshwork of very minute tubes the capillaries which 
 can now be observed easily. 
 
 Improvements in the microscope enabled Malpighi in 
 1660 and Leeuwenhoek in 1688 to demonstrate the 
 completion of the circuit of the blood by microscopic 
 observations of the movement from arteries to veins 
 
vi INQUIRY AND INTERPRETATION 139 
 
 through the capillaries, and it can now be seen easily 
 by any student who will examine the web of a frog's 
 foot. The largest blood vessels seen are the small 
 arteries bringing the blood from the heart, the finest 
 are the capillaries through which the blood passes into 
 the small veins which carry it back to the heart and thus 
 complete the circuit. 
 
 Harvey's work was an excellent example of the 
 application of the inductive method of study laid down 
 by Francis Bacon as the essential principle of scientific 
 progress ; but Harvey did not begin to teach the circula- 
 tion of the blood until 1619, and as Bacon died seven 
 years later he may be forgiven the omission of any 
 reference to it in his writings, though he must have 
 known of it. Harvey's opinion of Bacon's doctrines 
 is represented by his remark, " He writes philosophy 
 like a Lord Chancellor." 
 
 John Hunter, who was born exactly a hundred years 
 after the publication of Harvey's work on the circulation 
 of the blood, paid no heed to Bacon's mechanical system 
 of arriving at scientific truth. This great anatomist, 
 biologist and surgeon, whose studies of t.he human 
 frame raised surgery from the art of the barber-surgeon 
 to the dignity of a science, and whose observations and 
 experiments embraced every object which he could 
 secure in the animal and vegetable kingdoms, did not 
 trouble about Baconian principles in his inquiries and 
 interpretations. He had a passion for knowledge, and 
 possessed the creative and constructive attributes 
 which enabled him to make discoveries and to co- 
 ordinate them. Writing to Jenner about certain 
 observations and experiments he desired him to make, 
 he said, "Be as particular as you possibly can " ; and 
 that sentence epitomises his scientific method. He 
 
140 DISCOVERY CH. 
 
 was rationally sceptical and critical of so-called facts, 
 and was always ready to put them and principles to 
 the test of experiment. 
 
 The principles of our art are not less necessary to be under- 
 stood than the principles of other sciences ; unless, indeed, the 
 surgeon should wish to resemble the Chinese philosopher whose 
 knowledge consisted only in facts. In that case, the science 
 must remain unimproved until new facts arise. In Europe, 
 philosophers reason from principles and thus account for facts 
 before they arise. John Hunter. 
 
 On one occasion there was a discussion at a meeting 
 at which Hunter was present as to the structure of 
 certain organs in the digestive system of birds. The 
 meeting adjourned without settling the question, and 
 on the next assembly quotations from the works of 
 Aristotle, Hippocrates, Galen and other authorities 
 were brought forward by the advocates of particular 
 views in support of their opinions. Hunter had not gone 
 to the early masters for confirmation, but had dissected 
 the organs and exhibited them on a plate. All the 
 books in the world and all the speculations of philo- 
 sophers throughout the ages are but feather-weights 
 in comparison with ocular evidence of this kind. 
 
 The desire to test and measure for himself instead 
 of accepting the observations and systems of ancient 
 astronomers as fixed standards of reference led to the 
 foundation of modern astronomy of precision by Tycho 
 Brahe (1546-1601). While a boy of thirteen at the 
 University of Copenhagen this young Danish noble 
 was impressed by the observation of a partial eclipse 
 of the sun, which had occurred punctual to prediction. 
 He then determined to train himself for an astronomer, 
 and when a youth of seventeen we find him making 
 measurements of a conjunction of the planets Jupiter and 
 
vi INQUIRY AND INTERPRETATION 141 
 
 Saturn on August 17, 1564, by means of an ordinary pair 
 of compasses. For a few years after, his attention was 
 given to other scientific subjects, but the appearance of 
 a remarkable new star in the constellation of Cassiopeia 
 in 1572 re-awakened his activity and fixed his career. 
 
 Thenceforth, he devoted his life to the accurate 
 determination of the positions and motions of celestial 
 bodies, and started a renaissance of astronomical 
 measurement. Until he began observations at his 
 observatory at Uraniborg on the island of Huen, the 
 astronomy of the ancients had remained practically 
 undisturbed. No advance had been made in the know- 
 ledge of the positions of the fixed stars or of the moon's 
 motion so important for navigation ; and the positions 
 of the planets could not be foretold with anything like 
 reasonable accuracy. 
 
 No astronomer had yet made up his mind to take nothing 
 for granted on the authority of the ancients ; but to determine 
 everything himself. Nobody had perceived that the answers to 
 the many questions which were perplexing astronomers could 
 only be given by the heavens, but that the answers would be 
 forthcoming only if the heavens were properly interrogated by 
 means of improved instruments capable of determining every 
 astronomical quantity anew by systematic observations. The 
 necessity of doing this was at an early age perceived by Tycho 
 Brahe. Dr. J. L. E. Dreyer. 
 
 For twenty-five years Tycho Brahe patiently and 
 diligently measured the positions of stars and other 
 bodies upon the celestial sphere, using instruments of 
 his own design and attaining an accuracy of observation 
 little short of marvellous. Upon the basis of these 
 observations Kepler constructed his three famous laws 
 of planetary motion. 
 
 Johann Kepler was born at Weil, in the Duchy of 
 Wurtemberg, in 1571. Refused as a divine, he pursued 
 
142 DISCOVERY OH. 
 
 the study of mathematics and was appointed professor 
 at Gratz in 1594, being then twenty-four years of age. 
 But five years later he was, as a Protestant, expelled 
 from Styria and went to join Tycho Brahe at Prague, 
 where for a number of years he endeavoured to fit 
 Tycho Brahe's wonderfully accurate observations into 
 the theories then held as to motions of bodies in the 
 solar system. 
 
 In the process of discovery of the three fundamental 
 laws known by his name, Kepler was led to make many 
 fantastic hypotheses. But all through he was guided 
 by the principle that God who made the world had 
 established fixed laws throughout his works, laws that 
 are often so definite as to be capable of expression 
 in exact numerical terms. In accordance with these 
 views he sought for numerical relations in the disposi- 
 tion of the planets and their arrangement, in respect 
 to their number, their times of revolution and their 
 distances from one another. Each hypothesis he made, 
 however fanciful, he tried by a rigorous test whenever 
 possible, and as soon as he found that the facts were 
 not in accordance therewith he abandoned it, and without 
 hesitation proceeded to try others, which he submitted 
 to the same severe ordeal, to share perhaps the same 
 fate. He says, " After many failures, I was comforted 
 by observing that the motions in every case seemed 
 to be connected with the distances ; and that when 
 there was a great gap between the orbits there was the 
 same between the motions." He was at length led to 
 the discovery of his well-known " Harmonic " law (the 
 squares of the periodic times of revolution of the planets 
 are as the cubes of their mean distances from the Sun). 
 
 The misery in which Kepler lived forms a painful contrast 
 with the services which he performed for Science. The pension 
 
vi INQUIRY AND INTERPRETATION 143 
 
 on which he subsisted was always in arrears ; and though the 
 three emperors, whose reigns he adorned, directed their ministers 
 to be more punctual in its payment, the disobedience of their 
 commands was a source of continual vexation to Kepler. When 
 he retired to Silesia, to spend the remainder of his days, his 
 pecuniary difficulties became still more harassing. Necessity 
 at length compelled him to apply personally for the arrears 
 which were due; and he accordingly set out in 1630, when 
 nearly sixty years of age, for Ratisbon ; but in consequence of 
 the great fatigue which so long a journey on horseback produced, 
 he was seized with a fever, which put an end to his life. Sir 
 David Brewster. 
 
 The astronomical views of early Greek philosophers 
 were summed up by Aristotle in the fourth century B.C. 
 There were many speculations as to the form of the 
 earth and the nature of celestial phenomena, but few 
 have any scientific significance. " Some say," remarked 
 Aristotle in one of his works, " that the earth rests on 
 water. We have ascertained that the oldest statement 
 of this character is the one accredited to Thales the 
 Milesian [639-546 B.C.], to the effect that it rests on 
 water, floating like a piece of wood or something of that 
 sort." Aristotle himself stated plainly that the earth 
 is a round globe, and Pythagoras (566-470 B.C.) is believed 
 to have taught that the earth moves in the heavens, 
 but Aristarchus of Samos, in the third century B.C., 
 was the first philosopher to suggest that the sun is the 
 centre of our system and that the earth revolves around 
 it in a year. When, however, four hundred years later, 
 Ptolemy of Alexandria built up his system of astronomy, 
 he adopted the doctrine of an immovable earth in the 
 centre of the universe, and this was accepted as true until 
 the time of Copernicus. 
 
 The earliest serious criticism of the views of Aristotle 
 and Ptolemy appear to have been made by Oresme, 
 who became Bishop of Lisieux, Normandy, in 1377, and 
 
144 DISCOVERY CH. 
 
 died at that place in 1382. In a translation of the four 
 books of Aristotle, Oresme commented upon Aristotle's 
 contentions for an immovable, central earth, gave 
 numerous reasons and arguments against this hypothesis, 
 and showed it to be unsound. The work in which this 
 was done was never published, though several manuscript 
 copies exist. Probably other thoughtful inquirers had 
 the same dissatisfaction with the theory of a fixed 
 central earth, but were unwilling to publish any criticism 
 of what was then the orthodox view. It was perhaps 
 fortunate for Copernicus himself that the work in which 
 he finally dethroned the earth from the position it had 
 held for so long and, following Aristarchus, made the 
 sun the centre of our system, was not published to the 
 world until he was on his death-bed in 1543. 
 
 In the plan of the solar system conceived by Coper- 
 nicus, the planets Mercury and Venus are nearer the 
 sun than is the earth ; and in the. course of their revolu- 
 tions around the body to which they owe their light 
 they must, therefore, exhibit phases like those through 
 which the moon passes monthly. Copernicus knew 
 that these phases were a consequence of his theory, 
 and predicted that they would be found to exist. One 
 of the first uses to which Galileo put his telescope in 
 1610 was the observation of Venus, and he wrote a full 
 account of the changes seen by him in the appearance 
 of the planet, from the fully-illuminated disc to the 
 crescent form and then through the half-moon aspect 
 to full again. The discovery of these phases provided 
 an unanswerable argument for the Copernican theory. 
 
 From the observation of these wonderful phenomena we are 
 supplied with a determination most conclusive, and appealing 
 to the evidence of our senses, of two very important problems, 
 which up to this day were discussed by the greatest intellects 
 with different conclusions. One is that the planets are bodies 
 
IV. URANIA - THE MUSE OF ASTRONOMY. 
 
 From the engraving by R. Earlom, (1742-1822), 
 after G. B. Cipriani (1727-1785). 
 
vi INQUIRY AND INTERPRETATION 145 
 
 not self-luminous (if we may entertain the same views about 
 Mercury as we do about Venus). The second is that we are 
 absolutely compelled to say that Venus (and Mercury also) 
 revolve round the sun, as do also all the rest of the planets. 
 A truth believed, indeed, by the Pythagorean school, by Coper- 
 nicus, and by Kepler, but never proved by the evidence of our 
 senses as it is now proved in the case of Venus and Mercury. 
 Galileo. 
 
 The discoveries made by Galileo with his telescope 
 excited the hostility of the expounders of Aristotelian 
 philosophy ; and they supported the Copernican doctrine 
 to such an extent as to bring him under the ban of the 
 Romish Church. He was denounced to the Inquisition 
 in 1612, but it was not until 1633 that proceedings were 
 taken which resulted in the observer of seventy years 
 of age being bound by oath to abjure the doctrine " that 
 the sun is at the centre of the universe and is immovable, 
 and that the earth is not the centre and is movable," 
 and being treated as prisoner for the last nine years of 
 his life. During this time, in his exile at Siena and 
 Arcetri, his interest in science never waned, despite his 
 infirmities, and he devoted himself to dynamical pro- 
 blems on which he was still at liberty to express opinions. 
 
 The Copernican doctrine was believed to be contrary 
 to Holy Scripture, and therefore Galileo was compelled 
 to renounce it and to do penance for teaching it. What- 
 ever was in his mind as he rose from his knees before the 
 ten Cardinals in the Convent of Minerva, Rome, on 
 June 22, 1633, we cannot know, but it is unlikely that 
 he muttered " Eppur si muove " and yet it moves 
 as is related in the familiar anecdote associated with 
 his abjuration. 
 
 The action of the Inquisition in forcing Galileo to 
 deny the evidence of his own senses cannot be con- 
 demned too strongly ; but the fact that the Church of 
 
 G.D. K 
 
146 DISCOVERY OH. 
 
 Rome was responsible for the recantation may almost 
 be said to have been incidental. Had the Salvation 
 Army or a council of politicians possessed the same 
 powers in those days, they would probably have been 
 just as active in crushing what was believed to be a 
 pestiferous doctrine for which the people were not 
 prepared and which was, therefore, a danger to the 
 State. We need not go back three hundred years to 
 find scientific workers who have been deprived of their 
 posts, or whose careers have been ruined, because of 
 their convictions. The man who to-day dared to teach 
 doctrines so revolutionary as those held by Galileo, so 
 opposed to conceptions of what is sacred, and contrary 
 to what public opinion considers to be true, may not be 
 tortured or imprisoned, but he would assuredly suffer 
 social ostracism and would lose position and friends as 
 sadly as Galileo did in his old age. 
 
 Copernicus put forward his doctrine of the arrange- 
 ment and movements of bodies in the solar system 
 hesitatingly, and merely as a hypothesis by which the 
 different positions of the sun and planets as seen from 
 the earth could be explained much more simply than 
 on a system involving an immovable earth in the centre 
 of the universe. Of a different type of mind was 
 Giordano Bruno, who had arrived at a like conception 
 of the cosmic system by intuition, and not only went 
 beyond Copernicus in his ideas but also in his fearless 
 advocacy of them. Thirty-three years before Galileo 
 had been brought before the Inquisition, Bruno had 
 declared to the same body his philosophical creed in 
 unmistakable terms. 
 
 I believe in an infinite universe, the effect of the infinite divine 
 potency, because it has seemed to me unworthy of the divine 
 goodness and power to create a finite world, when able to produce 
 
vi INQUIRY AND INTERPRETATION 147 
 
 besides it another and others infinite ; so that I have declared 
 that there are endless particular worlds similar to this of the 
 Earth ; with Pythagoras I regard it as a star, and similar to it 
 are the moon, the planets, and other stars, which are infinite, 
 and all these bodies are worlds, and without number, constituting 
 the infinite all (universita) in an infinite space ; while the latter 
 is called the infinite universe, in which are innumerable worlds ; 
 so that there are two kinds of infinity, one in the magnitude of 
 the universe, the other in the multitude of worlds, by which 
 indirectly the truth according to the faith may be impugned. 
 In this universe I place a universal providence, in virtue of which 
 everything lives, grows, moves, and comes to and abides in its 
 perfection. Giordano Bruno. 
 
 For teaching these doctrines Bruno was handed over 
 to the governor of Rome in 1600, with the usual recom- 
 mendation that he be punished " with as great clemency 
 as possible, and without effusion of blood" an equivocal 
 form of words which signified burning at the stake. 
 He had been eight years a prisoner of the Inquisition 
 and could have secured his release at any time by for- 
 saking the truth as it had been revealed to him, but an 
 unbending sense of right kept him stedfast to the end. 
 When his sentence was pronounced he uttered the 
 memorable words, " You who sentence me are in greater 
 fear than I who am condemned." 
 
 The fear of death was no part of Bruno's philosophy. 
 " I have fought," he said, " that is much victory is 
 in the hands of fate. Be that as it may with me, this 
 at least future ages will not deny of me, be the victor 
 who may that I did not fear to die. Yielded to none 
 of my fellows in constancy, and preferred a spirited 
 death to a cowardly life." For liberty of thought and 
 freedom of science he perished, and his executioners 
 believed they were preserving Truth from desecration 
 when they burned the body of the man who willingly 
 offered himself up as a living sacrifice to her, 
 
148 DISCOVERY CH. 
 
 The fundamental principles of the Copernican system 
 are : (1) That the apparent daily motion from east to 
 west of the celestial sphere and the bodies in it, is due 
 to the daily rotation of the earth on its axis from west 
 to east ; (2) That the earth is one of a family of planets 
 revolving round the sun. Neither of these propositions 
 were established by conclusive proof until long after 
 the time of Copernicus. It was understood that if the 
 earth moves around the sun, the stars ought to undergo 
 an apparent annual displacement of position on account 
 of being viewed from different positions. Tycho Brahe 
 endeavoured to detect such a displacement, but unsuc- 
 cessfully, and on that account he rejected the doctrine 
 of the earth's motion. Great improvements had to be 
 made in astronomical instruments before the difference 
 of position of a star as seen from opposite sides of the 
 earth's path around the sun could be measured. Not 
 until about 1840 were observations of sufficient accuracy 
 made to establish this kind of displacement, from which 
 also the distance of a star could be determined. 
 
 It is nob strange that the displacement should have 
 escaped detection for so long now that we know how 
 very minute is the difference of position due to the earth's 
 annual motion. Imagine a circle an inch in diameter 
 to be drawn somewhere on an extensive plain ; let this 
 circle represent the path which the earth traverses 
 around the sun annually ; and let there be a luminous 
 point representing a star four miles away from it. 
 What the astronomer has to measure is comparable to 
 the difference of the apparent position of this point of 
 light as viewed from different parts of the one-inch 
 circle four miles distant. Suppose two lines were 
 drawn from the light to the circle at points as far apart 
 as possible ; the angle between these lines represents 
 
vi INQUIRY AND INTERPRETATION 149 
 
 the dimension which has to be measured in order to 
 find the distance of the nearest star. 
 ^ The minuteness of the angle may be understood by 
 considering the movement of the minute hand of a 
 clock or watch. If the hand moves at a perfectly 
 uniform rate there will be a difference of position at the 
 beginning and end of a second or any smaller interval 
 of time. The angle between two positions separated 
 by about the five-hundredth part of a second represents 
 the angle due to the movement of the earth around the 
 sun when the nearest star is observed ; and this notwith- 
 standing the fact that the earth is ninety-three millions 
 of miles from the sun, so that by its revolution around 
 the sun its position with regard to the stars is changed 
 by nearly two hundred million miles. 
 
 Using an illustration due to Prof. E. C. Pickering, the 
 apparent change of position of the nearest star, as the 
 earth moves to points nearly two hundred million miles 
 apart, is equal to the height of a man at a distance of 
 two hundred miles. In other words, the problem of 
 determining the apparent displacement due to change 
 of the earth's position in its orbit is like measuring the 
 height of a man two hundred miles away. So accurate 
 are the methods now used by astronomers that the 
 height of the man could be determined with an uncer- 
 tainty of only one inch. Yet in spite of the marvellous 
 precision with which measurements can be made, only 
 about forty stars have been found near enough to our 
 system for any angular displacement to be detected 
 sufficiently large to admit of the determination of 
 their distances. Few stars are less than a million 
 times farther from us than the sun, and most of them 
 are probably thousands of times more distant than 
 the nearest. 
 
150 DISCOVERY OH. 
 
 The fact that stars undergo a measurable annual 
 displacement upon the vault of heaven is an indirect 
 proof of the revolution of the earth around the sun, but 
 a direct proof of this movement is available in the 
 " aberration of light." The observations which led 
 James Bradley (1693-1762) to the discovery of this 
 important .astronomical effect were made in the coal 
 cellar of a house at Wanstead in the early part of the 
 eighteenth century. Those were the days when very 
 long telescopes were used as a means of avoiding the 
 coloured fringes which appear around the images pro- 
 duced by an object-glass consisting of a simple lens. 
 The lens of Bradley's telescope was on the roof, and the 
 eye-piece end was placed in the coal cellar, so as to be 
 as far away as possible ; holes being cut in the intervening 
 floor to allow the instrument to pass through. 
 
 Bradley used this instrument to measure the position 
 of a star with the view of discovering the apparent 
 effect, known as " parallax," which must be produced 
 by the change in the earth's point of view an effect 
 sought for by Tycho Brahe and other astronomers, but 
 not then established beyond question, though its exist- 
 ence was a fundamental consequence of the Copernican 
 theory. Bradley did not find what he expected, but 
 his observations showed that all stars seemed to shift 
 slightly from their true places in periodic fashion and 
 by the same amount. The paths followed were similar 
 to what would be produced if the earth's orbit around 
 the sun were projected in miniature upon the back- 
 ground of space. This wandering or aberration could 
 not be confused with parallax due to the change in the 
 point of view, for the shift was the same for all stars, 
 whereas apparent displacement due to parallax would 
 differ for stars at different distances. 
 
vi INQUIRY AND INTERPRETATION 151 
 
 Bradley pondered over his observations for two or 
 three years before he was able to interpret them. The 
 solution, when found, proved to be very simple, and 
 may be illustrated by a familiar example of a similar 
 effect. Suppose we are seated in a train or motor car, 
 and that rain is falling vertically, or nearly so. The 
 lines followed by the rain-drops are seen upright while 
 the carriage is at rest, but immediately it moves they 
 seem to be tilted forward at the top ; and the faster 
 we travel the greater is the deviation from the vertical. 
 If we did not know that the rain was falling in vertical 
 lines, we might think it was falling from points ahead 
 of us, but we know that the slant is only apparent, and 
 is due to the motion of the train or car. The effect is 
 produced by a combination of the velocities of the 
 carriage and the falling rain, and is precisely similar 
 to that observed by Bradley in the case of the stars. 
 The earth travels around the sun at a rate of nearly 
 nineteen miles a second, and the stream of light coming 
 to us from every star has a velocity of 186,000 miles a 
 second. Consider the earth to be the carriage of the 
 illustration and light- waves to be the rain, and ifc is 
 easy to understand that the combination of the two 
 velocities must cause every star to be seen slightly 
 ahead of its true position. 
 
 As the velocity of light is about ten thousand times 
 that of the earth, the amount of the- deviation due to 
 aberration may be represented by two lines each nearly 
 three hundred yards long drawn from the observer's 
 eye toward a star and separated at the upper ends by 
 the length of an inch. The angle between these two 
 lines is equivalent to the " constant of aberration " 
 discovered by Bradley by observations in a coal-cellar 
 in 1726. Bradley afterwards became Astronomer Royal, 
 
152 DISCOVERY CH. 
 
 and the improvements he effected at Greenwich during 
 his tenure of the office provided astronomers with a 
 mine of exact knowledge of the positions and movements 
 of stars. The lesson taught by his life is that perfection 
 should be aimed at, and the best use made of the instru- 
 mental means available, even though the significance of 
 the observations may not be understood. 
 
 Many men of science have built better than they knew 
 for future generations because of their attention to this 
 principle of precision throughout their investigations. 
 About the middle of the eighteenth century L. Euler, 
 a Swiss mathematician, showed that, considering the 
 earth to be a rigid body, it should oscillate slightly, as a 
 top does when it spins ; that is to say, the direction of 
 the axis should vary in a period which was calculated 
 to be about three hundred days, and therefore the 
 positions of the north and south poles, which are the 
 extremities of the axis, and the latitudes of all places, 
 should be subject to a like periodic variation. 
 
 Observations of sufficient precision to establish this 
 variation of latitude were not made until one hundred 
 and fifty years later, when S. C. Chandler, of Cambridge, 
 Mass., and F. Kiistner, of Berlin, proved that it 
 amounted to nearly six seconds of angular measurement 
 an amount which would cause each of the poles of 
 the earth to wander in a curve about sixty feet in 
 diameter around the mean position. More detailed 
 observations have since been made in various parts 
 of the world, and the results have enabled the details 
 of the paths and periods of this wandering of the 
 poles to be made out, as well as the conclusion to 
 be arrived at that the earth must be a little more rigid 
 than a globe of steel in order that the observed effects 
 may take place. Here, again, a result was arrived at 
 
vi INQUIRY AND INTERPRETATION 153 
 
 by mathematics before it was found actually to exist 
 in Nature. 
 
 Scientific theory is established by cumulative 
 evidence of this kind. The Copernican theory is held 
 to be true, because it accounts completely for the 
 varying aspects of the heavens as seen from different 
 parts of the earth and at different times ; it describes 
 the movements of the celestial machinery, and when 
 the law of gravitation had proved to be the mainspring, 
 the two principles combined provided astronomers with 
 everything required for the construction of an accurate 
 time-table of the heavenly bodies in the past, present 
 or future. The powerful instrument which has thus 
 been placed in the hands of astronomers, and the use 
 made of it, has been described in impressive words. 
 
 Supply any man with the fundamental data of astronomy, the 
 times at which stars and planets cross the meridian of a place, 
 and others matters of this kind. He is informed that each of 
 these bodies whose observations he is to use is attracted by all 
 the others with a force which varies as the inverse square of their 
 distance apart. From these data he is to weigh the bodies, 
 predict their motion in all future time, compute their orbits, 
 determine what changes of form and position these orbits will 
 undergo through thousands of ages, and make maps showing 
 exactly over what cities and towns on the surface of the earth 
 an eclipse of the sun will pass fifty years hence, or over what 
 regions it did pass thousands of years ago. A more hopeless 
 problem than this could not be presented to the ordinary human 
 intellect. The men who have done it are therefore in intellect 
 the select few of the human race. The astronomical ephemeris 
 is the last practical outcome of their productive genius. Prof. 
 Simon Newcomb. 
 
 Observation, interpretation, prediction, realisation, 
 are successive stages of scientific theory. Astronomy, 
 being the oldest branch of science, can furnish the most 
 perfect links in this chain of reasoning, but remarkable 
 
154 DISCOVERY OH. 
 
 examples are found in other departments of natural 
 knowledge. 
 
 By acute reasoning from observed facts relating to 
 the character and arrangement of the coal-fields and 
 associated rocks of Somersetshire and South Wales on 
 the west, and of the Belgian and North French coal- 
 fields on the east, Lieut.-Col. Godwin- Austen showed in 
 a memorable paper to the Geological Society of London 
 in 1856 that, in all probability, similar coal-fields 
 were buried beneath the newer strata of the intervening 
 region. Combining all the observations then available, 
 he finally concluded that there were coal-fields in the 
 south-east of England sufficiently near the surface to 
 allow of their being of great economic value. 
 
 This prediction of the existence of coal, based upon 
 purely geological considerations, has been fulfilled, and it 
 affords a striking example of the application of scientific 
 reasoning. Whether the quantity and quality of the 
 coal in Kent will make its working a profitable under- 
 taking has yet to be proved, but in spite of this, it is 
 little short of marvellous that geologists should be able 
 to see in imagination the coal seams extending under- 
 ground from England to Belgium and France, and should 
 be able to say so confidently, " Seek, and ye shall find," 
 to the prospectors who have followed them. The pre- 
 diction of the existence of coal in Kent, hundreds of 
 miles from the great coal-fields, is a remarkable example 
 of successful scientific induction based upon careful 
 observations. 
 
 New results and new ideas often meet with severe 
 criticism in the scientific world. Newton's experiments 
 with a glass prism were marvels of accurate study and 
 cautious conclusion, yet they brought him more trouble 
 than praise. He proved that white light is not 
 
vi INQUIRY AND INTERPRETATION 155 
 
 homogeneous but consists of rays which, are refracted 
 or bent by different amounts when they pass through 
 a prism, the deviation from the original direction in- 
 creasing gradually from red light successively through 
 orange, yellow, green, blue and indigo to violet, which 
 is the light that undergoes the greatest amount of 
 refraction. He concluded from his researches " That 
 the colours of all natural bodies have no other origin 
 than this ; that they are variously qualified to reflect 
 one sort of light in greater plenty than another " ; but 
 no sooner was this and like truths as to the nature of 
 colour announced than they were bitterly assailed by 
 philosophers who were unfamiliar with the experiments 
 upon which they were based, or held other views upon 
 light and colour. 
 
 No wonder such opposition was disturbing to Newton, 
 and that it almost made him decide to do no work except 
 for his private satisfaction. " I was so persecuted with 
 discussions arising out of my theory of light," he wrote 
 in 1675, " that I blamed my own impudence for parting 
 with so substantial a blessing as my quiet to run after 
 a shadow " ; and a year later he remarked, " I see a 
 man must either resolve to put out nothing new, or to 
 become a slave to defend it." 
 
 Everyone is now so familiar with electrical phenomena 
 that the explanation of lightning as an electric discharge 
 between two clouds, or a cloud and the earth, and of 
 thunder as the sound of the discharge, is readily intelli- 
 gible. Before the eighteenth century, when experi- 
 ments with various machines for producing electric 
 and other curious effects had excited great attention, 
 many strange conjectures had been made as to the 
 nature of lightning and thunder. Anaximander con- 
 sidered the phenomena as " caused by the wind enclosed 
 
156 DISCOVERY CH. 
 
 in a thick cloud, which, by reason of its lightness, 
 breaketh forth violently, the rupture of the cloud 
 maketh a crack, and the divulsion by reason of the 
 blackness causeth a flashing light." 
 
 This represents an early attempt to account for the 
 phenomena on a naturalistic basis, instead of referring 
 them to Jove and his thunderbolts. Clouds clashing 
 together instead of cracking seem to the child to provide 
 sufficient reason for the cause of thunder a view 
 expressed by Milton in the lines : 
 
 As when two black clouds, 
 
 With heaven's artillery fraught, come rattling on 
 Over the Caspian ; then stand, front to front 
 Hovering a while, till winds the signal blow 
 To join their dark encounter in mid-air. 
 
 Later views were that lightning and thunder were 
 caused by the explosion of gases in the air, or by the 
 spontaneous combustion of particles of "a subtle 
 sulphur." No means existed for the production of long 
 " electric sparks " and, therefore, no suggestion could 
 be made of any relation between such discharges and 
 those taking place in the clouds. Early experimenters 
 with electrical machines did not overlook the resem- 
 blance between the flash and crack of their electric 
 sparks and the similar effects observed during thunder- 
 storms. Benjamin Franklin, in 1749, stated the points 
 of similarity between the electric discharges and 
 lightning to be : (1) Giving light, (2) Colour of the light, 
 (3) Crooked direction, (4) Swift motion, (5) Being con- 
 ducted by metals, (6) Crack or noise in exploding, (7) 
 Subsisting in water or ice, (8) Rending bodies it passes 
 through, (9) Destroying animals, (10) Melting metals, 
 (11) Firing inflammable substances, (12) Sulphurous 
 smell. 
 
vi INQUIRY AND INTERPRETATION 157 
 
 It remained to establish the identity of the machine- 
 made electricity with lightning flash and thunder-clap, 
 and Franklin suggested a means of doing this by fixing 
 a pointed rod at the top of a high tower or steeple and 
 using it to draw down the lightning for the purpose of 
 comparing its effects directly with those produced by 
 electricity. Before Franklin could raise the money 
 for the erection of his pointed rod on a tower, Dalibard 
 had obtained electricity from the clouds by means of a 
 rod about forty feet long, fixed at the ground level upon 
 an insulated stand near Paris. He instructed an old 
 dragoon to try to obtain electric sparks by bringing a 
 brass wire fixed in a glass bottle near the rod when 
 thunderclouds were seen. 
 
 After several days' waiting, a thunder-cloud appeared on 
 May 10, 1752. The dragoon approached the wire to the rod, 
 and there was a lively crackling of sparks. The flame and 
 sulphurous odour were evidently infernal. The terrified dragoon 
 dropped the wire and shouted to his neighbour to send for the 
 village priest. The latter was braver than the dragoon. He 
 began to experiment for himself, and drew sparks from the rod. 
 He communicated the results to Dalibard, who wrote, " Franklin's 
 idea ceases to be a conjecture. Here it has become a reality." 
 Prof. F. Cajori. 
 
 While Franklin, not quite convinced, was still hoping 
 for the funds to place his rod at the top of a steeple in 
 Philadelphia, so as to get as high up as possible, the 
 happy idea occurred to him of using a kite for this 
 purpose. Electricity was to be conducted down from 
 the thundercloud by the twine attached to the kite, and 
 a silk ribbon tied to the end of the twine near the hand 
 was to prevent it from going any further. A key was 
 to be tied at the place where the twine and ribbon 
 joined, so as to form a metal conductor. 
 
 In June, 1752, Franklin sent up his kite towards the 
 
158 DISCOVERY OH. 
 
 clouds. He put his knuckles near the key, but obtained 
 no sparks. Again and again he tries to draw an electric 
 spark from the key, yet without success. Is his con- 
 jecture wrong and the experiment a failure ? No, the 
 rain has now wetted the twine and made it a better 
 conductor of electricity. Once more Franklin presents 
 a knuckle to the key, and a strong spark is the result. 
 He obtains a succession of sparks, and uses the electricity 
 from the clouds to produce the same effects as that 
 from man-made machines. He has established the 
 identity of lightning and electricity, and answered Job's 
 question, " Canst thou send lightnings, that they may 
 go, and say unto thee, ' Here we are ' ? " Facts were 
 at last available upon which a reasonable theory as to 
 the nature and origin of lightning could be based. 
 
 Writers in the popular press, and in technical papers 
 also, frequently indulge in cheap sneers at what they call 
 " scientific theory." In their minds, the man of science 
 lives in a world far removed from the realities of life, 
 and knows little of material things or practical possi- 
 bilities. Nothing could be more incorrect than this 
 view. With the exception of pure mathematics and 
 metaphysics, every branch of physical and natural 
 science depends for its progress upon practical work in 
 the laboratory or the field. No one appreciates the 
 value of experimental work more than the man of 
 science, and no one is more critical of scientific theory. 
 Whenever a theory is put forward in scientific circles, 
 it is always subjected to severe attack from people most 
 competent to point out its weaknesses ; and in any case 
 it only survives until someone brings forward evidence 
 which disproves it. 
 
 For example, Newton supported with the weight of his 
 great authority the theory that light is due to the 
 
vi INQUIRY AND INTERPRETATION 159 
 
 emission of minute particles at a high velocity by a 
 luminous body. When these particles impinge upon 
 the retina of the eye, they produce the sensation of light. 
 According to this view, light ought to travel more quickly 
 in water than in air. Another theory, put forward by 
 Huygens about Newton's time, and developed later, is 
 that light is due to vibration in an imaginary medium 
 called the ether, believed to prevail throughout all space. 
 Luminous bodies set the ether in vibration, and when 
 these undulations reach the eye they give us the sen- 
 sation of light. On this view, light should travel more 
 slowly in a substance like water than it does in air. 
 
 To test the two theories, therefore, an experiment 
 was required by which the relative velocities of light in 
 air and in water could be determined. By Newton's 
 emission theory the velocity should be greater in water 
 than in air ; while according to Huygens's undulatory 
 theory it should be less. Not until the middle of the 
 nineteenth century was a means found of determining 
 experimentally the velocities of light in water and air 
 in a laboratory. The crucial experiment which would 
 decide which theory was true was performed by a 
 French physicist, Jean Leon Foucault, in 1850 ; and it 
 showed that light, which travels at the rate of about 
 186,000 miles a second in air, travels through water at 
 about three-quarters that velocity. The result of this 
 experiment disposed finally of the emission theory, and 
 re-established Huygens's theory that light is due to 
 very rapid vibrations in a hypothetical ether pervading 
 the universe. 
 
 Fifty years before the crucial determination was made 
 of the velocities of light in water and air, a genius of the 
 first magnitude Dr. Thomas Young had shown that 
 red light is produced by nearly 32,000 ether-waves to 
 
160 DISCOVERY OH. 
 
 the inch, and that the number of such waves in a given 
 length increases progressively in passing from red to 
 violet, until at this end of the colour scale there are 
 about 60,000 undulations to the inch. Young also 
 proved that certain optical effects could be explained 
 only by the principle of interference of ether- waves with 
 one another ; but his researches and interpretations, 
 involving as they did the existence of an imponderable 
 ether which, to use his words " pervades the substance 
 of all material bodies, with little or no resistance, as 
 freely, perhaps, as the wind passes through a grove of 
 trees," met with ridicule from leaders in the literary 
 world, and were not given serious attention by his 
 scientific contemporaries. When in 1815 a French 
 investigator, Augustin Jean Fresnel, began experimental 
 work in optics, and was also led to the discovery of 
 interference in light, he knew nothing of the previous 
 work done by Young in the same direction thirteen 
 years earlier. The work of these two investigators 
 revived the undulatory theory and opened a question 
 which may be said not to have been settled decisively 
 until Foucault's crucial experiment had been made. 
 
 Here, then, we have an instance of a scientific theory 
 being abandoned when it had been shown to be untenable 
 by decisive experiment. It is possible that, as knowledge 
 increases, the theory which has held its own for three- 
 quarters of a century, may have to be modified ; indeed, 
 researches in the domain of radioactivity have proved 
 the existence of minute particles moving with the high 
 velocities demanded by Newton's corpuscular theory 
 of light. It has yet to be shown, however, that such 
 particles can account for optical phenomena as com- 
 pletely as the wave-theory does, though they are probably 
 concerned with radiation of all kinds. 
 
vi INQUIRY AND INTERPRETATION 161 
 
 The point on which we wish to insist is that men of 
 science do not regard theories as dogmas to be held at 
 all costs, and in face of all contradictory evidence, but 
 as ways in which phenomena can be explained. Often 
 the theory or the rule is wrong ; and it should only be 
 accepted as an approach to truth when it can be put to 
 the test. There must be theories and hypotheses, but it 
 is necessary to distinguish them from the results of 
 careful and accurate observation. The road along which 
 the progress of science has been accomplished is strewn 
 with the remains of hypotheses and theories broken 
 upon the Procrustean bed of facts of observation. A 
 hypothesis is merely a provisional or working explanation 
 of phenomena faithfully observed and recorded, and it 
 must be discarded when further observations prove it 
 to be untenable. In the acceptance of this principle, 
 the scientific type of mind differs from that which is 
 content to accept medieval scholastic philosophy as a 
 final court of appeal for new knowledge. 
 
 The poet perceives in Nature resemblances and 
 meanings which are hidden to the ordinary mind. The 
 truly great man of science likewise uses imaginative 
 insight in his theoretical conceptions, and it enables him 
 to project known facts into unknown regions and see the 
 picture produced upon the new mental plane. Many 
 great discoveries have been made by this scientific use 
 of the imagination ; but in all cases they have depended 
 upon a basis of fact revealed by observation or experi- 
 ment. There must be knowledge before any useful 
 hypothesis or assumption can be formed as to what 
 should follow from it. The hypothesis which represents 
 an effort of imaginative power not founded upon a wide 
 range of facts may pass as fiction, but it has no place in 
 science. 
 
 G.D. L 
 
162 DISCOVERY CH. 
 
 Given the results of observation or experiment, the 
 philosopher endeavours to discover a law or principle 
 connecting them. He guesses at their meaning, and 
 invents a hypothesis which will not only explain what is 
 known, but also suggest consequences which may, or may 
 not, be confirmed by future investigations. Prof. A. 
 Senier relates that von Hofmann used to say to him and 
 other research students working in the Berlin laboratory, 
 " I will listen to any suggested hypothesis, but on one 
 condition that you show me a method by which it 
 can be tested." Without such a condition, the creations 
 of a disordered mind would be as worthy of consideration 
 as the speculations of a scientific genius ; and fertile 
 ideas would be sought not in a laboratory but in an 
 asylum. A hypothesis ought, therefore, to be capable 
 of being verified, even though the means may not be 
 available of applying a crucial test to it at the time ; 
 it ought also to be sufficiently definite to admit of proof 
 or condemnation. 
 
 Imagination as distinguished from fancy is an essential 
 attribute of the scientific mind that makes for progress. 
 " With accurate experiment and observation to work 
 upon," says Tyndall, " imagination becomes the archi- 
 tect of physical theory. Newton's passage from a 
 falling apple to a falling moon was an act of the prepared 
 imagination. Out of the facts of chemistry the con- 
 structive imagination of Dalton formed the atomic 
 theory. Davy was richly endowed with the imaginative 
 faculty, while with Faraday its exercise was incessant, 
 preceding, accompanying and guiding all his experi- 
 ments. His strength and fertility as a discoverer are 
 to be referred in great part to the stimulus of the 
 imagination." Darwin was equal to Faraday in im- 
 aginative power ; he was continually forming theories, 
 
vi INQUIRY AND INTERPRETATION 163 
 
 but his fertility in this respect was balanced by the 
 power of severe criticism to which he subjected the 
 products of his imagination. His son says that he was 
 willing to test what would seem to most people not at 
 all worth testing ; and that he enjoyed making what 
 he called " fools' experiments " to judge whether a 
 view or hypothesis was false or true. 
 
 In science, however, the value of the imagination 
 increases with breadth of knowledge. A child may 
 imagine the stars to be windows in the vault of heaven, 
 and their twinkling the fluttering of angels' wings 
 passing in front of them. His conception of the stellar 
 universe may be beautiful, but it differs widely from 
 that on which the astronomer endeavours to construct a 
 scientific cosmogony. 
 
 How easy it is to overlook objects and phenomena 
 when their significance is not understood is illustrated 
 by an incident related by Darwin himself. While a 
 student at Cambridge, he went to Wales with Sedgwick, 
 the professor of geology, and examined the rocks for 
 fossils. This was before Agassiz had shown that at one 
 period of geological history the rocks of the country 
 must have been buried beneath a sheet of ice which 
 left unmistakable marks of its action upon them. 
 " But," says Darwin, " neither of us saw a trace of the 
 wonderful glacial phenomena all around us ; we did 
 not notice plainly scored rocks, the perched boulders, 
 the lateral and terminal moraines. Yet these pheno- 
 mena are so conspicuous that, as I declared in a paper 
 published many years afterwards in the Philosophical 
 Magazine, a house burnt down by fire did not tell its 
 story more plainly than did this valley." 
 
 Imaginative writers may produce fantastic romances 
 in which future conditions are portrayed, but neither 
 
164 DISCOVERY OH. VT 
 
 they nor the prophet who bases his prediction upon 
 existing knowledge can forecast with any confidence 
 the character of new discoveries. It is often easy to 
 foretell the development and further application of 
 knowledge already acquired, but this system of extra- 
 polation of curves of existing conditions cannot take 
 into consideration the discovery of new factors which 
 may alter, and frequently do alter, the trend of tendency. 
 Even an author like Mr. H. G. Wells, with wide scientific 
 learning upon which to build his brilliant romances, 
 could not anticipate such discoveries as wireless tele- 
 graphy, Rontgen rays or radium, though he could fore- 
 see extensions of existing knowledge, and visualise social 
 effects of progressive science and invention. 
 
 Science advances by opening completely new fields of 
 knowledge upon which the literary man or investigator 
 may exercise their intellectual activities, and the 
 directions in which these domains are to be found are 
 rarely indicated with success in romantic or in scientific 
 literature. Because it is impossible to know what 
 future work will bring forth, purely imaginative forecasts 
 of things to come are probably as much, or as little, to 
 be depended upon as strictly logical conclusions based 
 upon accomplished fact. True it is that " whether 
 there be prophecies, they shall fail ; whether there be 
 tongues, they shall cease ; whether there be knowledge, 
 it shall vanish away." 
 
CHAPTER VII 
 LAW AND PRINCIPLE 
 
 The great tragedy of science the slaying of a beautiful 
 
 hypothesis by an ugly fact. Huxley. 
 Consistency in regard to opinions is the slow poison of the 
 
 intellectual life, the destroyer of its vividness and its 
 
 energy. Sir Humphry Davy. 
 Of all monarchs Nature is the most just in enactment of 
 
 laws, and the most rigorous in punishing the violation 
 
 of them. Wilkins. 
 
 Though the mills of God grind slowly. 
 
 Yet they grind exceeding small : 
 Though with patience he stands waiting, 
 
 With exactness, grinds he all. Longfellow. 
 Nature is so varied in her manifestations and phenomena, 
 
 and the difficulty of elucidating their causes is so great, 
 
 that many must unite their knowledge and efforts in 
 
 order to comprehend her and force her to reveal her laws. 
 
 Laplace. 
 For Nature, Time is nothing. It is never a difficulty : 
 
 she always has it at her disposal : and it is for her the 
 
 means by which she has accomplished the greatest as well 
 
 as the least results. Lamarck. 
 
 IN a scientific sense, a natural law is merely a precise 
 statement of the relationship between certain results 
 of observation. Facts must first be collected by obser- 
 vation or measurement ; then they have to be classified 
 and compared with the view of finding any relationship 
 existing between them. When a relation is discovered 
 
166 DISCOVERY en. 
 
 which shows the dependence of one group of facts upon 
 another, it is called a scientific law, or a law of Nature. 
 Often the law can be expressed in mathematical terms ; 
 but it may be only a brief description in words of certain 
 relationships in the field of Nature. In either case, 
 there must be no exception to the law. The laws of 
 civil life can be broken, and sometimes are broken 
 deliberately in order to direct attention to their injustice. 
 But a law of Nature is simply a statement of relationship, 
 and when observations prove the statement to be incor- 
 rect, then the law has to be abandoned or modified to 
 take the new facts into consideration. 
 
 The method of science, indeed, is the method of the Chancery 
 Court it involves the collection of all available evidence and 
 the subjection of all such evidence to the most searching examina- 
 tion and cross examination. False evidence may be tendered 
 and for the time being accepted ; but sooner or later the psrjury 
 is discovered. Our method, in fact, goes beyond that of the 
 courts : we are not only always prepared to reconsider our 
 judgments but always searching for fresh evidence ; we dare 
 to be positive only when, time after time, the facts appear to 
 warrant a definite conclusion. Prof. H. E. Armstrong. 
 
 The broad generalisation which is accepted as a law 
 of Nature by one generation may thus prove to be only 
 an approximation to the truth when fuller knowledge 
 has been acquired. When a formula expressing relation- 
 ships between facts or phenomena in Nature is so exact 
 and comprehensive that it suffices for whatever new 
 knowledge has been gained by the increase of perceptive 
 powers from one generation to another, it stands out 
 as a great achievement of scientific thought. 
 
 The grand, and indeed only, character of truth is its capability 
 of enduring the test of human experience, and coming unchanged 
 out of every possible form of fair discussion. Sir John Herschel. 
 
 Pre-conceived ideas and traditional beliefs are drags 
 
vii LAW AND PRINCIPLE 167 
 
 on the chariot of truth. By meditation Plato arrived 
 at the doctrine that the planets move at uniform rates 
 in circles. A circle was conceived to be the most perfect 
 figure, therefore it was concluded to represent the 
 appropriate path of a heavenly body, without any refer- 
 ence to actual observation or experience. For fifteen 
 hundred years Plato's principle of uniform motion in 
 circles was not disputed, and even Copernicus, while 
 constructing his revolutionary system, regarded it as 
 an axiom that " The movement of the heavenly bodies 
 is uniform, circular, perpetual, or else composed of 
 circular movements." The difficulties which this tradi- 
 tion introduced in trying to make observation fit theory 
 were explained in one way or other, but there were 
 always errors or defects which could only be accounted 
 for by complicated reasoning. 
 
 When Kepler began his analysis of Tycho Brahe's 
 accurate observations of the positions and motions of 
 heavenly bodies, particularly of the planet Mars, he 
 tried numerous combinations of circles and epicycles 
 with the view of finding a theory to account for them 
 completely. The Copernican theory was sufficient to 
 explain the general aspects of the heavens, but the 
 principle of uniform circular motion postulated by it 
 for the planets was unable to satisfy the standards 
 of precise measurement. Kepler found that when 
 theory was confronted with observation there was 
 always an error of eight or nine minutes of angular 
 measurement, and this amount he believed to be 
 impossible in such careful observations as were made 
 by Tycho Brahe. The amount is about equal to one- 
 fourth the apparent angular diameter of the sun, or to 
 the angle subtended by a halfpenny looked at squarely 
 from a distance of a dozen yards. " Out of these eight 
 
168 DISCOVERY CH. 
 
 minutes," said Kepler, " we will construct a new theory 
 that will explain the motions of all the planets." 
 
 All previous theories had assumed the existence of 
 uniform circular movement ; and it was only when this 
 doctrine had to be abandoned that Kepler was led to 
 the truths embodied in his three famous laws of planetary 
 motion. In the first of these laws the Platonic principle 
 was disestablished for ever, for it states that the planets 
 do not move in circles but in ellipses, and that the sun 
 is situated at a focus of each ellipse. The second law, 
 announced at the same time, in 1609, defines the rate 
 of movement and shows that a planet moves fastest 
 when nearest the sun and slowest when most distant. 
 The third fundamental truth, which was not discovered 
 until nine years later, is known as the Harmonic law, 
 and gives precisely the relation that exists between 
 periods of revolution and distances from the centre 
 of motion. By means of this law, the distance of a 
 planet from the sun, in comparison with the earth's 
 distance, can be calculated when the period which the 
 planet takes to make a complete revolution round the 
 sun is known. In the work in which he announced this 
 law, the discovery of which had occupied twenty years 
 of his life, Kepler wrote in words of unfeigned delight : 
 
 that for which I joined Tycho Brahe, for which I settled in 
 Prague, for which I have devoted the best part of my life to 
 astronomical contemplations, at length I have brought to light, 
 and recognised its truth beyond my most sanguine expectations 
 . . . the die is cast, the book is written, to be read either now 
 or by posterity, I care not which ; it may well wait a century 
 for a reader, as God has waited six thousand years for an observer. 
 Kepler. 
 
 The meaning of Kepler's three laws of planetary 
 motion remained a mystery until Newton's discovery 
 of the principle or law of universal gravitation. By 
 
vii LAW AND PRINCIPLE 169 
 
 this discovery not only were the facts then known as 
 to celestial forms and movements capable of explanation, 
 but also every case to which the principle has since 
 been applied. 
 
 Nature and Nature's laws lay hid in night. 
 
 God said, " Let Newton be ! " and all was light. Pope. 
 
 There had been many surmises as to the nature of the 
 force which keeps the planets in their courses around 
 the sun and makes the moon describe its path around the 
 earth. It had been shown that the strength of the force 
 of attraction between two bodies does not diminish, as 
 Kepler supposed, in the simple ratio of the distance 
 separating them, that is, is halved when the distance 
 is doubled, but varies as the square of the distance. 
 When the distance is doubled, the force is thus reduced 
 to one-quarter, when trebled, to one-ninth, and so on. 
 The problem was to account for the movements of the 
 planets and their satellites in elliptical orbits upon the 
 assumption of a force varying in this way. 
 
 In January, 1684, Sir Christopher Wren offered Hooke 
 and Halley " the present of a book of forty shillings " 
 if either of them could bring him a convincing demon- 
 stration within two months that such a force would 
 cause a planet to move in an ellipse. The demonstration 
 had not been given in August of the same year when 
 Halley went to Cambridge to consult Newton on the 
 subject. Without mentioning any of the speculations 
 of Wren, Hooke or himself, he asked at once : 
 
 " What will be the curve described by the planets on the sup- 
 position that gravity diminishes as the square of the distance ? " 
 
 Newton answered immediately, " An ellipse." 
 
 " How do you know ? " asked Halley in amazement. 
 
 " Why," replied Newton, " I have calculated it," and he 
 proceeded to search for the calculation, but unsuccessfully. 
 
170 DISCOVERY OH. 
 
 Halley returned to London with the knowledge that 
 the problem had been solved, but without the demon- 
 stration, which, however, reached him in November, 
 and early in the following year was communicated to 
 the Royal Society. Halley was thus the means of 
 bringing Newton's immortal discovery to light ; and 
 he used justly to boast that he had been " the Ulysses 
 who produced this Achilles." 
 
 Twenty years before this, in 1665, Newton's mind 
 had been directed to the subject of gravity. He had 
 left Cambridge on account of the plague, and was in 
 the garden of his home at Woolsthorpe, Lincolnshire, 
 speculating upon the power of gravity, when an apple 
 fell from a tree and is said to have started a train of 
 thought which led to the discovery of the universal law 
 "of gravitation. There is little foundation for this 
 anecdote ; and in Newton's case the fall of an apple 
 was certainly not needed to originate a speculation to 
 which several natural philosophers of his day had given 
 attention. 
 
 An isolated fact can be observed by all eyes ; by those of the 
 ordinary person as well as of the wise. But it is the true physicist 
 alone who may see the bond which unites several facts among 
 which the relationship is important, though obscure. The 
 story of Newton's apple is probably not true, but it is symbolical ; 
 so let us think of it as true. Well, we must believe that many 
 before Newton had seen apples fall, but they made no deduction. 
 Facts are sterile until there are minds capable of choosing between 
 them and discerning those which conceal something and recog- 
 nising that which is concealed ; minds which under the bare 
 fact see the soul of the fact. Henri Poincare. 
 
 The free fall of an object on the earth made a con- 
 venient point of departure for Newton's mental excursion 
 into space ; and the line of reasoning was : a body falls, 
 or is pulled toward the earth's centre by a force which is 
 
vii LAW AND PRINCIPLE 171 
 
 called gravity ; does this force extend beyond the earth 
 to the moon, and if so, will it account for the motion of 
 our satellite around the earth ? 
 
 A stone dropped from a height upon the earth's 
 surface falls 193 inches in a second ; how far would it 
 fall in the same time if it were dropped from the distance 
 of the moon ? Assuming that the centre of attraction 
 may be regarded as at the centre of the earth, the moon 
 is sixty times farther away from this point than is the 
 earth's surface. The force would, therefore, be not 
 60 times less but 60x60, or 3,600 times less, for it 
 diminishes according to the square of the distance. To 
 make an accurate calculation of the amount, however, 
 requires a correct knowledge of the distance from the 
 earth's centre to the surface, that is, of the earth's 
 radius. 
 
 Taking the value accepted in 1666, Newton calculated 
 that the moon would fall toward the earth by 44 
 thousandths of an inch in a second ; in other words, 
 this is the amount by which the path of the moon 
 should deviate from a straight line in a second in order 
 to describe its curved path around the earth in a month. 
 The amount by which the moon actually swerves from 
 a rectilinear path in a second is 53 thousandths of 
 an inch, so Newton saw that the calculated result did 
 not agree with what was then considered to be fact. 
 The discrepancy between theory and observation " in- 
 duced him to abandon the subject, and pursue other 
 studies with which he had been previously occupied." 
 
 Not until 1684 did he " resume his thoughts concerning 
 the moon." A few years before that time an accurate 
 determination of the size of the earth had been made by 
 Picard, and this gave a more correct value of the length 
 of the earth's radius than had previously been accepted. 
 
172 DISCOVERY CH. 
 
 Using the new value, Newton again took up the cal- 
 culation of the moon's deflection from a straight path, 
 on the assumption of the force controlling it being the 
 same as that which causes bodies to fall on the earth, 
 but diminished in strength on account of the distance 
 of the moon from the earth. The result now obtained 
 showed that the central force should cause the moon 
 to swerve from a straight line path by 53 thousandths 
 of an inch in a second, which is exactly the amount that 
 will produce the curved path described by the moon 
 around the earth. As the calculations which were thus 
 to extend the domain of gravity from the earth to the 
 universe were drawing to a close, it is related that Newton 
 was " so much agitated that he was obliged to desire a 
 friend to finish them." 
 
 It must not be supposed for a moment that the 
 problem of testing the theory of gravitation by the 
 motion was so simple as it is here presented. In order 
 to establish the principle, Newton had to prove that as 
 regards gravitational attraction, a globe like the sun, 
 moon, or earth behaves as if the force due to the whole 
 of the mass resided at the centre alone. This conclusion 
 was only arrived at after infinite labour and by the 
 employment of a new mathematical method invented 
 by him. By this same method also he was able to prove 
 that the path of a body under the influence of attraction 
 depending upon a central force could be an ellipse or 
 any other related curve. The elliptical paths of the 
 moon around the earth, the earth and other planets 
 around the sun, and of all satellites around their primary 
 planets were explained by this discovery ; yet, as we 
 have seen, Newton was content with having found it, 
 and only through the intervention of Halley was the 
 world made aware of it. 
 
vii LAW AND PRINCIPLE 173 
 
 This is not the place to show that the law of universal 
 gravitation provides a complete explanation of Kepler's 
 three laws of planetary motion, or to discuss its profound 
 significance. A law of Nature is tested by its ability 
 to meet all the cases to which it may be applied ; and 
 in not a single instance has the law of gravitation been 
 found wanting in this respect. It explains the fall of 
 bodies on the earth, and the motions of the planets and 
 their satellites ; it enables the paths of comets to be 
 calculated, and the disturbances to which they may be 
 subjected in passing near more massive bodies ; it is 
 used to determine the masses of bodies in our solar 
 system, and of stars revolving round one another, and 
 is applied to calculate the tide-raising effects of the sun 
 and moon ; while by it tables of the moon's movements 
 are calculated to a high degree of perfection for use in 
 determining longitude at sea ; and it does all this without 
 any need of amendment. 
 
 It has been truly said that " The tendency of the 
 human mind is to exaggerate the possibilities of the 
 unknown." Wherever there is ignorance, Nature is 
 dreaded as much as a child dreads darkness. The 
 appearance of a comet in the sky caused whole nations 
 in earlier days to tremble with fear because nothing 
 was known of the nature and movements of these bodies. 
 From the time that Newton showed that comets travel 
 round the sun in 'definite paths under the control of 
 gravitational attraction, the feeling of awe and anxiety 
 formerly produced by such celestial visitors has been 
 diminishing. They are now looked upon as interesting 
 spectacles instead of being regarded as heralds of 
 disaster. 
 
 Edmund Halley was inspired by Newton's work to 
 calculate the paths of a number of comets. He found 
 
174 DISCOVERY CH. 
 
 that three comets, which appeared in 1531, 1607, and 
 1682, had practically the same path or orbit, and he 
 concluded that they were really one and the same body 
 travelling around the sun in a period of about seventy- 
 five years. He predicted, therefore, that the comet 
 would appear again in the year 1758, or thereabouts ; 
 that is, seventy-six years after 1682. He knew he would 
 not be alive to see if the prediction was fulfilled, but he 
 expressed the hope that, when the comet was seen, 
 posterity would remember the prediction had been 
 made by an Englishman. This was the first prediction 
 of the periodic return of a comet, and Halley's boldness 
 in making it was justified completely. The comet, 
 which was anxiously awaited, appeared in 1758 and 
 again in 1835 and 1910. By examining old records, 
 Halley's comet, as it is properly named, has been traced 
 back in steps of about seventy-five years to the year 
 240 B.C. 
 
 Newton showed that the law of gravitation was suffi- 
 cient to account for the motion of the comet of 1680 
 to which he applied it ; and since then the paths of 
 hundreds of comets have been calculated on the same 
 principle. Most comets are unannounced visitors to 
 the solar system, called from the depths of space by 
 the attractive influence of the sun, but following paths 
 which carry them away again into the outer darkness. 
 Some, however, like Halley's comet, tra verse orbits which 
 are closed curves, and these return after an interval 
 which may be reckoned in years or hundreds of years. 
 But the path of every comet of which sufficient observa- 
 tions are available is calculated upon the basis of 
 the law of gravitation. The apparently adventitious 
 motions of these bodies are thus reducible to perfect 
 law and order ; and the decline of the superstitious 
 
vii LAW AND PRINCIPLE 175 
 
 dread in which they had been held may be said to have 
 begun with Newton's discovery. 
 
 A notable example of the prediction of the existence 
 of a body from consideration of its gravitational influence 
 was afforded by the discovery of the planet Neptune. 
 After the planet Uranus had been discovered in 1781 
 by Sir William Herschel, astronomers calculated the 
 path in which it moved, and predicted the positions it 
 should occupy from time to time. The planet was found, 
 however, to be slightly behind or ahead of its calculated 
 position. If we know a train is moving at a certain 
 rate, we can say where it ought to be on the line at a 
 certain time, and if it is not there we assume that some- 
 thing has happened. So it was with the planet Uranus : 
 the difference between the actual and the calculated 
 positions of the planet was assumed to be due to the 
 disturbing influence of some unknown body beyond it. 
 
 There was every confidence that a massive globe 
 somewhere in the darkness of space was making its 
 presence manifest ; and though the problem of finding 
 the place of the disturber was very difficult, it was solved 
 by two mathematicians one an Englishman named 
 Adams and the other a Frenchman named Le Verrier. 
 In September, 1846, Sir John Herschel, son of Sir William 
 Herschel, said : " We see it [the probable new planet] as 
 Columbus saw America from the shores of Spain. Its 
 movements have been felt trembling along the far- 
 reaching line of our analysis with a certainty hardly 
 inferior to that of ocular demonstration." On the 
 twenty-third of the same month a German astronomer, 
 Dr. Galle, found the new body close to the place which 
 calculation had shown it ought to occupy. This is 
 probably the greatest triumph of mathematics applied 
 to the law of gravitation yet achieved. 
 
176 DISCOVERY CH. 
 
 The law of gravitation has proved to be a universal 
 key which has opened the door of many secret places 
 in Nature, yet what the key itself is or wherein lies 
 the cause of the attraction of gravitation is still to 
 seek. Now that the interstellar ether is becoming 
 almost as familiar to us as a household word, and its 
 recondite properties are being unravelled, there is, 
 perhaps, some prospect of the problem being solved. 
 Efforts have been made to discover whether gravita- 
 tional force is propagated instantaneously through space. 
 If we could suddenly create or destroy a centre of 
 attraction, as we can a beam of light, the answer would 
 be fairly easy. But as it is, we can only watch whether 
 changes of position among the heavenly bodies produce 
 their proper effect upon other bodies at once or after 
 a measurable lapse of time. So far, no evidence of 
 such a lapse of time has been forthcoming, although 
 the most favoured theories demand it. 
 
 One of those theories, originally due to Le Sage, sup- 
 poses that an infinite number of very small " ultra- 
 mundane " particles is constantly traversing space in 
 all directions. They are partly intercepted by ponderable 
 matter. Hence two bodies will shield each other from 
 the particles on one side, and the bombardment on the 
 outside will drive them together, producing an apparent 
 " attraction " between them. Reasons have been 
 found for the conclusion that at a certain great distance 
 gravitational attraction is intercepted altogether. If 
 this were true, Newton's grand conception of universal 
 gravitation would have to be modified, and we should 
 have to consider the visible universe as held together 
 by beams of light. 
 
 Next to the law of gravitation, the greatest generalisa- 
 tion established bv science, and the one to which likewise 
 
VTI LAW AND PRINCIPLE 177 
 
 no exception has been found, is the law of the conserva- 
 tion of energy, which asserts that though energy can be 
 converted from one form to another it cannot be created 
 or destroyed. A related generalisation of much greater 
 antiquity is the law of the conservation of matter, upon 
 the foundation of which modern chemistry has been 
 built. Whenever a chemical change takes place, whether 
 in the burning of a candle, the explosion of gunpowder, 
 or in any other form, the weight of the substances 
 produced is equal to the sum of the weights of the 
 constituents involved in the change. Since Lavoisier 
 enunciated this principle, the most accurate investiga- 
 tions have failed to detect a loss or gain of the minutest 
 particle of matter ; and the permanence of the amount of 
 material in our universe is, therefore, an axiom of science. 
 The Sicilian philosopher, Empedocles, born about 
 494 B.C., seems to have been the first to associate changes 
 of matter into various forms with force or energy. He 
 regarded fire and earth and air and water as the four 
 " elements," and said they were influenced by two 
 dynamic powers or principles Love and Strife one 
 tending to bring them together and the other to separate 
 them. In his universe there was no creation or absolute 
 destruction of the " elements," but only changing 
 combinations and transformations. " For," he said, 
 " from what does not exist at all it is impossible that 
 anything can come into being, and it is neither pos- 
 sible nor perceivable that being should perish com- 
 pletely." By considering the four material " elements " 
 as eternal but changing in composition through the 
 action of forces of attraction and repulsion, Empedocles 
 approached nearer than any other early philosopher to 
 the modern doctrines of the conservation of matter and 
 the relation between matter and energy. 
 
 G.D. M 
 
178 DISCOVERY OH. 
 
 A corollary upon the doctrine of the indestructibility 
 of matter is that an atom may in its time play many 
 parts. When Shakespeare made Hamlet say : 
 
 Imperial Caesar, dead and turned to clay, 
 Might stop a hole to keep the wind away, 
 
 he was only expressing the belief in transmigration held 
 by Empedocles. " For in truth I was born a boy and 
 a maiden, and a plant and a bird, and a fish whose 
 course lies in the sea." Our bodies may be buried or 
 burnt, but in either case the elements of which they are 
 composed will merely take other places in a never- 
 ending cycle, while the energy or soul of life will manifest 
 itself in other forms. 
 
 The idea of the conservation of mass is easy to under- 
 stand, but that of the conservation of energy is less 
 obvious and is, perhaps, best explained by a concrete 
 illustration. When a certain amount of energy is caused 
 to actuate a machine, a certain amount of useful work 
 may be obtained from it, but the efficient output is 
 always less than the energy supplied, on account of loss 
 due to friction between various parts of the machine. 
 When the energy thus wasted is accounted for, the total 
 is the same as that of the original supply ; hence no 
 machine can be constructed to give out in the form of 
 available work as much energy as is put into it ; and, 
 therefore, perpetual motion is impossible. Expressed 
 in other words, we never get something for nothing in 
 Nature. Commission has to be paid whenever energy 
 is exchanged from one form into another ; and even 
 with the most efficient engine the charge for the trans- 
 formation is very high. 
 
 The heat produced by the combustion of coal repre- 
 sents energy which is utilised to convert water into 
 
vii LAW AND PRINCIPLE 179 
 
 steam and thus drive engines. Suppose a certain 
 amount of coal to be" capable of generating 100 units 
 of heat when burnt in the furnace of an engine. About 
 25 per cent, of this quantity of heat is lost from various 
 causes, and 75 per cent, reaches the engine in the steam. 
 Only 6 of these units, however, are convertible into 
 the mechanical work represented by the driving of the 
 engine, and the remaining 69 per cent, is lost. If the 
 6 units are used to drive a dynamo for the production 
 of electric power, 1 has to be paid as commission for the 
 exchange, thus leaving us with 5 units. Let these 5 
 units be used to drive an electric motor ; the mechanical 
 energy obtained represents about 4J units, half a unit 
 being lost in the transformation. The final result, 
 therefore, of the transformation of energy from the com- 
 bustion of coal to the work obtainable from an electric 
 motor is, that of the prime value of 100 units of energy, 
 95| per cent, is lost by the various exchanges. In the 
 whole series of these or any other related changes, the 
 items on the two sides of the balance sheet give the 
 same total, the energy supplied being always equal to 
 the sum of the useful and useless energy obtained. 
 
 Traces of the idea of the conservation of energy may 
 be found amongst the writings of ancient philosophers, 
 and Descartes held that it was a self-evident truth. To 
 establish the truth, however, precise and detailed inves- 
 tigations were necessary, and these were not made until 
 nearly the middle of the nineteenth century, when 
 interest in the question appears to have been wide- 
 spread. 
 
 Towards the close of the eighteenth century, Count 
 Rumford and Sir Humphry Davy conceived the idea that 
 there was some correspondence between work done and 
 heat produced, but they did not realise completely that 
 
180 DISCOVERY CH. 
 
 mechanical energy and heat were reciprocally convert- 
 ible. A French philosopher, Sadi Carnot, saw the 
 connection between the two forms of energy represented 
 by heat and mechanical work, and he announced in 
 1824 that the expenditure of a given amount of work 
 would produce a definite quantity of heat, but his 
 conclusions received no recognition at the time. The 
 problem was to measure exactly the amount of work 
 which must be done to obtain a given quantity of heat ; 
 that is, to determine the mechanical equivalent of heat. 
 
 Seguin in France calculated this relationship by observ- 
 ing the fall of temperature of steam when expanding 
 against external pressure. From 1842 to 1847 J. E. 
 Mayer, K. F. Mohr, and H. von Helmholtz, in Germany, 
 and L. A. Colding, in Denmark, all arrived indepen- 
 dently, by various lines of reasoning and experiment, at 
 the great generalisation of the conservation of energy, 
 but the work which established the principle upon the 
 solid ground of accurate measurement was done by a 
 scientific amateur, James Prescott Joule, a brewer at 
 Salford, near Manchester. 
 
 By a number of careful experiments Joule showed 
 that a definite quantity of heat was always produced 
 by the expenditure of a definite amount of mechanical 
 work. When a pebble is dropped from a bridge into a 
 stream flowing beneath, the impact with the water pro- 
 duces a certain quantity of heat, the quantity depending 
 upon the weight of the pebble and the distance of the 
 fall. Joule found that the fall of a pound weight 
 through a distance of 778 feet always generated sufficient 
 heat to raise the temperature of a pound of water one 
 degree Fahrenheit. 
 
 Probably this conclusion does not strike you as ve 
 remarkable ; neither did it appear so to the membe 
 
 ne 
 
 : 
 
vn LAW AND PRINCIPLE 181 
 
 of the British Association before whom the experiments 
 were described in 1843, Joule being then a young man 
 of twenty-five years of age, completely unknown in 
 the scientific world. Genius dwells with the Gods 
 on Mount Olympus, and only a few daring spirits climb 
 up from the valleys to worship at its shrine. This is 
 as true of science as it is of art, or literature, or music. 
 Commonplace work can be understood by the many, 
 but original conceptions demand effort to comprehend 
 them, and they are, therefore, usually unregarded, or 
 if noticed, condemned. 
 
 Undaunted by the chilling reception which his com- 
 munication received, Joule continued his researches, 
 and in 1845, and also in 1847, he presented accounts of 
 further investigations to two othei meetings of the 
 British Association. On the latter occasion he was 
 asked by the chairman of the section to confine himself 
 to a short verbal description of his experiments ; and 
 his work would again have gone unheeded but for the 
 presence of another young man, William Thomson, 
 afterwards Lord Kelvin. What happened was described 
 many years afterwards by Joule himself : 
 
 Discussion not being invited, the communication would have 
 passed without comment if a young man had not risen in the 
 section, and by his intelligent observations created a lively 
 interest in the new theory. The young man was William 
 Thomson, who had two years previously passed the University 
 of Cambridge with the highest honours, and is now probably 
 the foremost scientific authority of the age. 
 
 Joule's discovery of the mechanical equivalent of 
 heat was not a result stumbled upon accidentally, but 
 a consequence of rigorous experiment, precise measure- 
 ment and philosophic thought. After he had assured 
 himself of the truth of the principle, Joule devoted 
 
182 DISCOVERY OH. 
 
 himself to the elaboration of methods of working, 
 modifying and repeating experiments in various ways 
 in order to determine its numerical value with increased 
 exactness. Many investigators have followed him 
 along the same roads, arriving at much the same value 
 as he did ; and the generalisation thus established 
 upon unimpeachable evidence is embodied in the First 
 Law of Thermodynamics, familiar to every mechanical 
 engineer as well as to all physicists, and expressed in 
 the words, " When work is transformed into heat, or 
 heat into work, the quantity of work is mechanically 
 equivalent to the quantity of heat." " Joule's initial 
 work," said Lord Kelvin, when unveiling a statue of 
 him at Manchester in 1893, " was the very foundation 
 of our knowledge of the steam engine and steam power. 
 Taken along with Carnot's work it gave the scientific 
 foundation on which all the great improvements since 
 the year 1850 had been worked out, not in a haphazard 
 way, but on a careful philosophical basis." 
 
 Joule's work stands in the esteem of men of science 
 by the side of that of Newton, yet when a movement 
 was started to commemorate it in Westminster Abbey, 
 the Dean of Westminster had to confess he was un- 
 acquainted with it, and only after some difficulty was 
 an area about two feet square in a dark corner placed 
 at the disposal of the memorial committee in the 
 English Valhalla. 
 
 " And so," says Sir Henry Roscoe, in describing the circum- 
 stances which led to the memorial, " a simple tablet is inserted 
 in one of the side walls just below the effigy of Charles Darwin ; 
 and thus within a foot or two of one another are placed the 
 simple and unattractive acknowledgments of work done, the 
 like of which hath not been seen, and the importance of which 
 cannot be reckoned. The ridiculous, if it were not the pathetic, 
 position thus accorded to two men who have conferred inestimable 
 
viz LAW AND PRINCIPLE 183 
 
 benefits not only on our own country but also on the world at 
 large, when compared with the grandiose monuments to political, 
 naval and military nonentities is, it must be confessed, a some- 
 what humiliating reflection on the lack of appreciation of science 
 shown in the English Temple of Fame. But, after all, this is 
 of little moment, for the names of Darwin and Joule will live 
 for ever in the minds and hearts of all those who appreciate 
 scientific worth." 
 
 The discovery of a law of Nature is always of great 
 advantage to scientific progress. By the warp and woof 
 of experiment, the man of science weaves a pattern 
 from the threads of evidence, and presents the result to 
 the world for anyone to use or improve. A further 
 example of this is afforded by the discovery, in 1826, by 
 George Simon Ohm, the son of a German locksmith, of 
 the law of electricity named after him. 
 
 Before Ohm commenced his investigations, many men 
 of science had studied the wonderful and manifold 
 effects of the electric current. Remarkable phenomena 
 were observed, but they formed only a tangled skein 
 until Ohm discovered a simple law stating the rela- 
 tionship between cause and effect in electricity. The 
 law is simply that the rate of flow of an electric current 
 is equal to the electric pressure divided by the resistance 
 offered to the current by the wire or other conductor 
 through which it is flowing. Ohm was working indepen- 
 dently and alone when he discovered this law ; and even 
 after he had established it beyond question he received 
 little recognition for his work, while from many sides 
 it was sharply criticised. It often happens that a 
 prophet is not without honour except in his own country 
 and among his own people, and this was the case with 
 Ohm, the importance of the work of the unassuming 
 German teacher being recognised in England before it 
 was in his native land. 
 
184 DISCOVERY CH. 
 
 Ohm's law is of universal application in electrical 
 engineering, and few problems can be worked without 
 making use of it. Except at extremely low temperatures, 
 such as those of liquid air and helium, the law has been 
 proved to be true even when put to the most searching 
 tests. It is one of the most accurately known laws of 
 Nature, and the most important recorded in the whole 
 range of the history of electrical science. The name of 
 the modest student, who never strove for show or glory, 
 is to-day upon the lips of thousands who are busy with 
 the work of electro-technical industries. In 1889, on 
 the hundredth anniversary of his birth, the Royal 
 Bavarian Academy of Sciences, Munich, celebrated his 
 services to posterity by a special meeting, and an address 
 was given, in the course of which the following inspiring 
 passage occurs : 
 
 The deeds of a man of science are his scientific investigations. 
 Truth once discovered does not remain shut up in the study or 
 the laboratory. When the moment comes, it bursts its narrow 
 bonds and joins the quick pulse of life. That which has been 
 discovered in solitude, in the unselfish struggle for knowledge, 
 in pure love of science, is often fated to be the mighty lever to 
 advance the culture of our race. When, nearly a hundred years 
 ago, Galvani saw the frog's legs twitch under the influence of two 
 metals touching, who could have suspected that the force of 
 Nature which caused those twitchings would transfer the thoughts 
 of man to far distant lands, with lightning's speed, under the 
 waters of the ocean would even render audible at a distance 
 the sound of the spoken word ? That this force of Nature 
 after man by ceaseless investigation had learned vastly to increase 
 its strength would illuminate our nights like the sun ! This 
 enormous development of electro-technology could only be 
 accomplished upon the firm foundation of Ohm's law. For only 
 he can govern a force of Nature who has mastered its law. Ohm, 
 by wresting from Nature her long-concealed secret, has placed 
 the sceptre of this dominion in the hands of the present. Prof. 
 E. von Lommel. 
 
vii LAW AND PRINCIPLE 185 
 
 Natural laws like those of Newton, Joule and Ohm 
 bear any strain to which they may be subjected ; they 
 connect cause and consequence so closely that predictions 
 based upon them can be made with complete confidence. 
 Each of these three laws refer to inanimate or mechanical 
 conditions ; the things embraced by them belong to 
 the regions of dead matter and blind force, and when 
 we pass to the biological world where organisms possess 
 individuality call it soul or spirit if you will no such 
 perfect truths as are found in physical science can be 
 expected. It is possible, however, to arrive at broad 
 generalisations, and the greatest of these is that of 
 organic evolution and its causes. 
 
 More than six hundred thousand different species of 
 animals have been described, while about half that 
 number of species of plants are known, and probably 
 natural science has not yet on its registers one half of 
 the numbers of animals and plants which actually exist. 
 Each of these separate species could be, and formerly was, 
 assumed to have been an object of special creation, but 
 a more reasonable view is that the various forms have 
 been evolved as the result of the action of natural pro- 
 cesses. 
 
 The idea of evolution goes back to Aristotle and other 
 early Greek philosophers who attempted to face the 
 problems of the origin and development of forms of life. 
 No real advance was, however, made in the use of 
 the idea in the long period of theologians and natural 
 philosophers which lasted until about the beginning 
 of the seventeenth century, when Greek traditions were 
 largely shaken off and the modern method of inductive 
 observation and reasoning may be said to have begun. 
 Among the lay writers of that century who suggested 
 that species of animals and plants might undergo change 
 
186 DISCOVERY CH. 
 
 in the course of time was Sir Walter Raleigh. In his 
 History of the World (1621), written during his imprison- 
 ment, referring to the days of the Flood, he said, " But 
 it is manifest, and undoubtedly true, that many of the 
 Species, which now seeme differing, and of several kindes, 
 were not then in rerum natura " ; and he remarked that 
 he could see no difference, except in size, between the 
 cat of Europe and the ounce of India, the dog-fish and 
 the shark, the dog and the wolf. 
 
 BufTon, the French naturalist, who is sometimes given 
 the credit of originating modern views of evolution, did 
 not go much farther than this nearly a century and a 
 half later. He surveyed natural history in a series of 
 sumptuous and comprehensive volumes, and inspired 
 interest in it by his animated style and bold speculation, 
 but though he suggested that new species of animals 
 and plants might be produced by progressive change, 
 and that all quadrupeds might have come from a few 
 original forms, he did nob indicate how the transforma- 
 tion could have taken place. Other naturalists and 
 philosophers who speculated upon the problems of 
 evolution in the eighteenth century were Goethe, who 
 held that " the more perfect organic natures, from 
 fishes to mammals, and man at their head, were formed 
 on one original type which still daily changes its form 
 by propagation," and Erasmus Darwin, who suggested 
 how successive generations of an organism might by 
 their actions or wants " New powers acquire, and larger 
 limbs assume." 
 
 But while these and many other writers had accepted 
 the doctrine of evolution in organic life, none had shown 
 with any force how the development had taken place. 
 The first serious attempt to discover the law governing 
 evolutionary changes was made by Jean de Lamarck, 
 
vii LAW AND PRINCIPLE 187 
 
 the eminent French zoologist, who devoted many years 
 of his life to studies of the problem of the origin of species. 
 The main points of the principle published by Lamarck 
 in 1801 are that animals may have their structures 
 modified by external conditions or by continued use or 
 disuse, and that the succeeding generation inherits the 
 modification. On this principle, the long neck of the 
 giraffe is explained by the constant straining of genera- 
 tions of the animal to reach the tender shoots at the tops 
 of trees, and the splay foot of the camel by continued 
 walking on desert sands. The two fundamental laws 
 of adaptation and heredity formulated by Lamarck to 
 account for the production of new species were stated 
 by him as follows : 
 
 1. In every animal which has not got beyond the period of 
 developing, the frequent and sustained use of any organ gradually 
 strengthens it, develops it, enlarges it, and gives it a power 
 proportionate to the duration of the using of it ; while the con- 
 tinued disuse of this or that organ imperceptibly weakens it; 
 and it deteriorates, loses its power by degrees, and finally 
 disappears. 
 
 2. All that Nature has allowed individuals to gain or lose by 
 the influence of the circumstances to which their race has been 
 exposed for a long time, and consequently, by the effect of pre- 
 dominant use of this organ or continued disuse of that, is con- 
 served in the new individuals who spring from them, and who, 
 therefore, find themselves better adapted than their ancestors, 
 if the conditions of existence have not changed. 
 
 Lamarck's principle thus states not only that variations 
 may be produced by the influence of external conditions, 
 or by exercise, but also that the new characters thus 
 acquired are inherited by succeeding generations. How 
 far the principle supplies the true cause of natural 
 processes has been a matter of much discussion in recent 
 years, but the proof of the inheritance of acquired 
 
188 DISCOVERY CH. 
 
 characteristics postulated by it has yet to be accepted 
 at the bar of scientific opinion. 
 
 Lamarck grasped the truth of organic evolution 
 better than any naturalist who preceded him, and he 
 carried out the principle on a far larger scale and in 
 greater detail than others had done, but his arguments 
 were not convincing. It was reserved for Charles 
 Darwin and Alfred Russel Wallace to import into the 
 problem an entirely fresh set of considerations, and to 
 establish a new and illuminating theory upon a secure 
 basis of fact. 
 
 As naturalist on H.M.S. Beagle during a five years' 
 voyage round the world, thrown upon his own mental 
 resources and furnished with many new and interesting 
 facts, Darwin was early confronted with many sides of 
 the process of evolution upon which to exercise his 
 imaginative and reasoning powers. The solitude of the 
 voyage and the almost continuous ill-health afterwards 
 " For forty years he never knew one day of health " 
 were contributing causes to the formation of those 
 original and suggestive ideas which were the foundation 
 of his greatness. 
 
 Upon returning home in 1836 Darwin began to look 
 for facts in relation to the origin of species, upon which 
 he had reflected long before. A year later, after reading 
 Malthus's Essay on the Principle of Population, it 
 occurred to him that in the struggle for existence among 
 animals and plants, individuals which possessed varia- 
 tions favourable to particular circumstances would tend 
 to be preserved, while those having unfavourable 
 variations would be destroyed. The result would be 
 the formation of a new species. Darwin fully understood 
 the possibility of new species being produced by 
 " sports " or " discontinuous variations," but he showed 
 
vii LAW AND PRINCIPLE 189 
 
 that evolution usually proceeds by taking advantage of 
 slight successive variations. This was the idea upon 
 which he never ceased working for twenty years, and 
 which culminated in the publication of his Origin of 
 Species, in 1859. 
 
 By collecting all facts which bore in any way on the variation 
 of animals and plants under domestication and nature, some 
 light might perhaps be thrown on the whole subject. My first 
 note-book was opened in July, 1837. I worked on true Baconian 
 principles, and, without any theory, collected facts on a wholesale 
 scale, more especially with respect to domesticated productions 
 by printed inquiries, by conversation with skilful breeders and 
 gardeners, and by extensive reading. Charles Darwin. 
 
 Variation is a common attribute of organic life ; no 
 two animals of the same kind are exactly alike in every 
 respect ; and the forms best adapted to particular 
 circumstances are the forms which survive longest and 
 carry on their kind. Life is always a struggle, and the 
 fittest for the time being are those which thrive best in 
 their surroundings. The intensity of the struggle for 
 existence, even in so large and open an arena as that 
 of the ocean, is shown by the small number of fish which 
 arrive at maturity in comparison with the immense 
 number of eggs produced. It is estimated that of the 
 five million or more eggs borne by a single codfish, all 
 except two or three meet with untimely deaths at 
 some stage of their career from the egg to the mature 
 adult. 
 
 Applications of the principle of natural selection can 
 be found throughout the kingdom of animate Nature, 
 but we will mention one only. After a severe storm of 
 snow and sleet in North America, Prof. H. C. Bumpas 
 collected one hundred and thirty-four sparrows which had 
 been rendered insensible by the weather. Of these birds 
 
190 DISCOVERY CH. 
 
 seventy-two survived, while sixty-two perished. On 
 comparing the survivors with the eliminated individuals, 
 very appreciable differences were found between them. 
 Nearly all the birds which were longer than the average 
 were among the dead, and the two shortest birds of the 
 whole number collected also perished. Natural selection 
 was, in fact, found to be most destructive of those birds 
 which departed most from the normal type. The general 
 conclusion drawn from the measurements of the birds 
 which survived or were eliminated was that the next 
 generation of sparrows in the storm-swept area would 
 be shorter in length, weigh less, have longer legs and a 
 greater brain capacity than the former generation. 
 
 Of course, many more observations of a similar kind 
 are required before a definite statement could be made 
 of the structural forms favourable or unfavourable to 
 survival. The measurements are valuable so far as 
 they go, but there may have been some characteristics 
 which could not be measured and yet were really the 
 determining causes of survival or death. It is, however, 
 safe to conclude that in general, both with plants and 
 animals, individuals which depart most from the normal 
 type are the first to be eliminated. Even with the human 
 race, we find genius dying early from neglect, while 
 mediocrity treads contentedly along a primrose path. 
 From the point of view of survival, it is just as bad to 
 be in advance of the time as behind it. 
 
 Wallace arrived independently at the solution of the 
 problem of evolution by means of the process of natural 
 selection, and, like Darwin, he was led to it by Malthus's 
 essay. It was Darwin's Journal, published in 1845, 
 and read by Wallace at the age of twenty-three, which 
 determined him to invite H. W. Bates to accompany 
 him on his journey to the Amazon and Rio Negro, 
 
vii LAW AND PRINCIPLE 191 
 
 which filled the four years 1848-52. Throughout his 
 whole career as a collector, Wallace had before him the 
 problem of evolution and the cause of the origin of new 
 species in animate nature. Before leaving for South 
 America, in 1848, he wrote : 
 
 I begin to feel rather dissatisfied with a mere local collection ; 
 little is to be learnt from it. I should like to take some one 
 family to study thoroughly, principally with a view to the theory 
 of the origin of species. By that means I am strongly of opinion 
 that some definite results might be arrived at. Dr. A. R. Wallace. 
 
 While at Sarawak, in 1855, Wallace was still pondering 
 over the problem, which was rarely absent from his 
 thoughts ; and in a paper written at that time he con- 
 cluded that every species which had come into existence 
 in Nature was closely related to a species which preceded 
 it. This pointed clearly to evolutionary development, 
 and suggested when and where new species would be 
 introduced ; but it did not indicate how they could be 
 brought into existence. After the publication of his 
 paper, Wallace was informed by his agent that several 
 naturalists had expressed regret that he was " theorising " 
 when what he was expected to do was to collect facts ; 
 nevertheless, he still continued to consider the reason 
 why one species becomes changed either slowly or 
 rapidly into another. Though the cause of the change 
 was unknown, the utilitarian mind considered it more 
 important to increase the size of a collection of birds 
 and insects of which Wallace himself had gathered 
 nearly nine thousand separate species than to discover 
 how the various distinct forms had originated. 
 
 In February, 1858, during a period of intermittent 
 fever at Ternate, he was pondering over the problem 
 when the conclusions arrived at by Malthus as to the 
 factors affecting increase or decrease of population 
 
192 DISCOVERY OH. 
 
 flashed upon him all the possible effects of the struggle 
 for existence. In two days the entire draft of the paper 
 showing the application of the views to organic species 
 in general was sketched and posted to Darwin, who had 
 been working upon the verification of the same idea 
 for twenty years. Darwin had actually written out a 
 sketch of his theory in 1842 ; and in 1844 this sketch 
 was enlarged to 230 folio pages, giving a complete 
 presentation of the arguments afterwards set forth in 
 the Origin of Species. 
 
 When Darwin received Wallace's paper he brought 
 the communication before Sir Charles Lyell and Sir 
 Joseph Hooker, and urged that it should be printed at 
 once. Upon their advice, however, he consented to let 
 an extract from the sketch of 1844 be presented to the 
 Linnean Society with Wallace's paper on July 1st, 1858. 
 " The one great result which I claim for my paper of 
 1858," said Wallace, " is that it compelled Darwin to 
 write and publish his Origin of Species without further 
 delay." 
 
 For evolution to proceed in any particular direction, 
 it is necessary for variations in that direction to be 
 encouraged continually, and for the trend of tendency of 
 the parent to be inherited by the offspring. Variation 
 and heredity are thus complementary to each other ; and 
 until the laws by which they are determined are under- 
 stood, no evolutionary theory can be said to be complete. 
 The rule of the road of heredity was discovered in 1866 by 
 Gregor Johann Mendel, an Augustinian monk, Abbot of 
 the old monastery at Briinn, Austria ; but the biological 
 world remained unaware of it for thirty years, and 
 Darwin died without knowing of the epoch-making work 
 of his contemporary. " Had Mendel's work," says 
 Prof. W. Bateson, the leading authority upon it, " come 
 
Pilots. I.. Knlin & L\\, I\jris. 
 
 V. THE THINKER. 
 Statue by Auguste Rodin, (1840-...), Pantheon, Paris. 
 
vii LAW AND PRINCIPLE 193 
 
 into the hands of Darwin, it is not too much to say that 
 the history of the development of evolutionary philo- 
 sophy would have been very different from that which 
 we have witnessed." 
 
 For eight years Mendel carried on experiments on 
 the hybridisation of peas and other plants in the large 
 garden of the cloister of which he was Abbot or Pralat. 
 He described his experiments in the Proceedings of the. 
 Natural History Society of Brunn, in 1866 and 1869, 
 and they remained unknown outside the circle of that 
 local society until the year 1900, when attention was 
 directed to them. He was in the habit of saying Meine 
 Zeit wird schon kommen my time will no doubt come 
 and his confidence has been fully justified. Since the 
 re-discovery of his two papers, the principles they teach 
 have been applied to hundreds of different plants and 
 animals, and Mendel's law has guided most studies of 
 heredity, while Mendelism has become a clearly-defined 
 branch of science. The white marble statue erected 
 to his memory in Briinn, in 1910, represents the esteem 
 in which scientific men of all nations now hold the 
 Abbot of the Konigskloster in that city. 
 
 It would be out of place here to describe in detail the 
 nature and consequences of Mendel's great biological 
 discovery, but we may sketch its main principle. Work- 
 ing with garden peas, Mendel found that different 
 characters, such as wrinkled or smooth seed, colour of 
 the seed-coats, form of the pods, length of the stem, and 
 so on, could be used to distinguish them. He observed 
 that when two plants differing by a given feature were 
 crossed, the hybrid offspring invariably exhibited one 
 of the parental characters to the entire or partial ex- 
 clusion of the other. Thus when tall varieties of peas 
 were crossed with dwarf varieties, the offspring were all 
 
 G.D. N 
 
194 DISCOVERY CH. 
 
 tall. This character of tallness was called by Mendel 
 " dominant," while the character of shortness, which 
 does not appear in the first generation of the hybrid 
 plants, was described as " recessive." 
 
 The tall hybrids were then allowed to fertilise them- 
 selves, and it might be supposed that they would breed 
 true ; but that was not the case. After self-fertilisation 
 each hybrid produced offspring in which the two original 
 parental characters dominant and recessive were 
 exhibited in the ratio, on the average, of three to one, 
 -there being in the case of tall and dwarf peas three tall 
 plants to one short. From the dwarf plants, when 
 self-fertilised, or fertilised from the original short stock, 
 only dwarfs can be obtained henceforth ; in other words 
 the recessive minority of the second generation breeds 
 true. Of the three tall plants belonging to the same 
 generation, one possesses the dominant character alone 
 and will produce only pure-bred or tall plants, when 
 self-fertilised ; but the two remaining plants are cross- 
 breds and these on self-fertilisation again give the 
 mixed generation of three plants possessing the dominant 
 character of tallness to one plant having the recessive 
 character of shortness. 
 
 The same simple rule was found by Mendel to be true 
 when plants differing in several characters instead of 
 one were cultivated ; and thousands of experiments 
 made by biologists since 1900 have shown that the 
 results of hybridisation discovered by him hold good 
 for specific characters exhibited by plants and animals of 
 many kinds. The work carried on by Mendel in the 
 seclusion of the cloister at Briinn has, indeed, put the 
 whole subject of heredity upon an entirely new footing, 
 and indicated a mode by which the isolation and per- 
 petuation of definite characters can be assured. 
 
vii LAW AND PRINCIPLE 195 
 
 The basal facts of Mendel's rule or principle of inherit- 
 ance have been abundantly established, but their inter- 
 pretation is not so simple, and they cannot be applied 
 to life in general until much more knowledge has been 
 obtained of essential dominant or recessive characters 
 in organisms and their physiological meaning. Neither 
 Darwinism nor Mendelism supplies more than a partial 
 interpretation of the operations of animate Nature, and 
 few biologists would now care to proclaim them as 
 impregnable truths. Whatever may be the ultimate 
 decision as to the determining lactors of evolution, we* 
 can say that Darwin was the first to describe the sig- 
 nificance of variation, and Mendel to show how the com- 
 plex threads of heredity could be disentangled. The 
 names of these two naturalists will be remembered for 
 all time as those of the two greatest contributors to the 
 theory of organic evolution. 
 
 In looking for the cause of evolution as against special 
 creation, the central fact which Darwin set himself to 
 explain was that of adaptation to environment, whereby 
 small differences were accumulated until new forms were 
 produced. No direct evidence as to this modifying 
 factor could be obtained from the geological record, 
 which was also too imperfect to show the transitions 
 from one species to another demanded by the theory. 
 The support which evolution was to receive from the 
 tablets of stone came later. 
 
 At the beginning of the nineteenth century it was well 
 understood by geologists that fossils provide a means of 
 determining the ages of the sedimentary rocks of our 
 globe ; they were accepted as convenient labels or signs 
 of relative antiquity, but little was known of their own 
 lines of development. Gradually, however, the view 
 was formed that there is no sharp distinction between 
 
196 DISCOVERY CH. 
 
 organisms existing in our own times and those repre- 
 sented by fossils ; and that in the course of ages simple 
 forms of life had been modified or developed into more 
 complicated or more perfect forms, until the highest 
 animals, and even man, were produced. On this view, 
 man is heir of all the ages, and in the course of his life 
 he climbs up his own genealogical tree from the condition 
 of simple cell to that of lord of creation. GeofYroy 
 St. Hilaire expressed this important relationship in the 
 words : " The embryological development of a living 
 creature is a summary of the phases of the palaeonto- 
 logical development of its species." 
 
 We have in this statement a clear recognition of the 
 evolution of animal forms in geological times as opposed 
 to that view that the various groups of fossils repre- 
 sented new creations at different epochs. By the study 
 of living forms Darwin showed that variation provided 
 a key though not the only key to the workshop of 
 organic Nature. He was not able to make much use of 
 the record of the rocks in marshalling the arguments for 
 evolution, but the gap was filled by the work of Huxley 
 in England, Albert Gaudry in France, E. D. Cope in 
 America, E. H. Haeckel in Germany, and other natura- 
 lists, in the latter half of the nineteenth century. 
 
 We happen to live in a world at a certain epoch, and 
 are apt to think this epoch the most important. Of 
 course, it is so for us individually, yet when the whole 
 history of the world is considered, the three score years 
 and ten of man are but an episode. Life upon the earth 
 has been continuous from the amorphous protoplasm 
 of the primeval shore to man in his most perfect form. 
 The animals of the past were the progenitors of those 
 of the present, and there must have been links connecting 
 the fossil and living forms. Palaeontologists have sought 
 
vii LAW AND PRINCIPLE 197 
 
 the bonds, the relationships, which unite the ancient 
 organisms to one another and to living forms ; and they 
 have proved each type to be related by definite charac- 
 teristics to its ancestors on one side and its descendants 
 on the other, until finally the fossil remains of man appear 
 associated with those of animals, and with the flint 
 implements which represented the first weapons of the 
 human race. 
 
 The use of fossils as convenient trade-marks by which 
 geological strata could be identified was established by 
 William Smith, but it was largely left to Gaudry to 
 show the genealogical relations of the different classes 
 of animals and their descent from primeval ancestors, 
 and thus to prove that evolution provides the reason for 
 particular fossils being found in particular geological 
 formations. " The stages of evolution of the fossils 
 which are brought to us for identification," he said, 
 " mark not only the modifications of organisation, but 
 also of the principal divisions of geological time. Taking 
 two different strata, if I find that in one the animals 
 indicate a condition of evolution less advanced than the 
 other, I conclude that the former are of the earlier age." 
 
 Much remains to be done before the complete story 
 of the transformations of the animal kingdoms of the 
 past can be told, but it is upon the evolutionary plan 
 that all discoveries of fossil forms are recorded and all 
 modifications of structure interpreted. The history of 
 life is written on the rocks by fossil remains, and the 
 record shows that from the beginning there has been a 
 steady upward tendency. Taken as a whole, the plants 
 and animals of to-day are far more highly organised, 
 varied and beautiful than in the past ages of the world, 
 and the future will probably see still higher forms of 
 life. But what of the beginning ? Evolution is not 
 
198 DISCOVERY OH. 
 
 creation, and biologists do not pretend to account for 
 the origin of life, but only to trace the changes it has 
 undergone and the conditions which produce them. 
 Increased knowledge of the older rocks has not shown 
 that we are nearer the fulfilment of the biologist's 
 dream, and the secret of Pandora's box remains still 
 undiscovered. 
 
 No sane man has ever pretended, since science became a 
 definite body of doctrine, that we know or ever can hope to 
 know or conceive of the possibility of knowing whence the 
 mechanism has come, why it is there, whither it is going, or what 
 may or may not be beyond and beside it which our senses are 
 incapable of appreciating. These things are not " explained " 
 by science and never can be. Sir Ray Lankester. 
 
 We have not yet reached the beginning of life. Though 
 science can trace and interpret the " footprints on the 
 sands of time," it knows not how life began or what 
 was the first created form. Deeper down than the 
 oldest rocks lies the mystery of creation ; deeper also 
 than the development of structural characteristics of 
 organisms may be the origin of mind and intelligence, 
 which do not admit of accurate measurement. The 
 process by which man has become a moral and ethical 
 being with a spiritual life may be different from that by 
 which animals and plants have advanced in perfection 
 of organisation. There seems, indeed, as Matthew 
 Arnold said, to be " something within ourselves which 
 makes for righteousness " apart from the principle of 
 cosmic evolution and often in conflict with it. 
 
 The principle of the struggle for existence and the 
 survival of the fittest must not, therefore, be understood 
 as a sanction for the exertion of brute force in the service 
 of egotism, but as a struggle towards higher planes and 
 the survival of the race. The road along which the 
 
vii LAW AND PRINCIPLE 199 
 
 course of evolution has advanced is not that of self- 
 interest, but of self-sacrifice, of the subjugation of the 
 individual to the needs of the type. There is indeed 
 very little evidence of any struggle for existence among 
 animals of the same species. Animals are, as a lule, 
 banded together for tribal protection, and those thrive 
 best which have the best organisation for mutual 
 defence. Evolution thus embodies the idea of social 
 ethics and makes the welfare of the community the 
 essential purpose of the life of the creature. The idea 
 that Darwinism signifies nothing more than striving 
 after personal or national mastery at all costs is a crude 
 misconception of this great principle, which was re- 
 pudiated alike by its founder and by Huxley, its most 
 powerful exponent, as contrary to the best ends of 
 civilisation. 
 
 The practice of that which is ethically best what we call 
 goodness or virtue involves a course of conduct which, in all 
 respects, is opposed to that which leads to success in the cosmic 
 struggle for existence. In place of ruthless self-assertion it 
 demands self-restraint ; in place of thrusting aside, or treading 
 down, all competitors, it requires that the individual shall not 
 merely respect, but shall help his fellows ; its influence is directed, 
 not so much to the survival of the fittest, as to the fitting of as 
 many as possible to survive. It repudiates the gladiatorial theory 
 of existence. It demands that each man who enters into the 
 enjoyment of the advantages of a polity shall be mindful of his 
 debt to those who have laboriously constructed it ; and shall 
 take heed that no act of his weakens the fabric in which he has 
 been permitted to live. Laws and moral precepts are directed 
 to the end of curbing the cosmic process and reminding the 
 individual of his duty to the community, to the protection and 
 influence of which he owes, if not existence itself, at least the life 
 of something better than a brutal savage. Huxley. 
 
 The existence of the spiritual or altruistic side of man's 
 nature cannot be said to be explained adequately by 
 
200 DISCOVERY OH. vn 
 
 natural selection ; as the fittest to survive under certain 
 conditions is often not the best ethically but the worst. 
 " In one aspect," said a leading naturalist, Sir William 
 Thiselton-Dyer, " the religious sentiment is a response 
 to a craving for a supernatural sanction to rules of con- 
 duct. Its varied but practically universal manifestation 
 amongst mankind has to be accounted for by evolution 
 just as much as the possession of a vertebral column. 
 It is not practically helpful to dismiss it as irrational." 
 
 No philosophic biologist would now insist that the 
 principle of natural selection, or any other plan of organic 
 evolution which leads up to man, is a complete expression 
 of the origin and expansion of human consciousness ; 
 but most naturalists are satisfied that the principle 
 truly represents perceptual operations of Nature. Be- 
 yond this concept there may be a new and transcendental 
 philosophy, but it belongs to the realm of metaphysics 
 rather than to that of observational science. 
 
CHAPTER VIII 
 CONQUEST OF DISEASE 
 
 Nowadays the serpent that bites man's heel is in nine cases 
 out of ten microscopic. Prof. J. A. Thomson. 
 
 Every disease has its own particular mode of production 
 from natural causes. Hippocrates. 
 
 Like other natural laws, the laws of health are inexorable 
 . . . Ignorance of the laws is not admitted as an excuse 
 any more than motive ; and the sentence for breaches 
 is true now as it was ages ago : "The soul that sinneth 
 it shall die" Sir Lander Brunton. 
 
 Just as the mechanical sciences, when viewed from a broad 
 standpoint, represent man's struggles for the control 
 of the energies available in his environment, so the 
 medical sciences have, as their ultimate aim, the 
 acquisition of control over the functions of man's body. 
 Prof. E. H. Starling. 
 
 THOSE who transgress the laws of man sometimes 
 escape punishment ; but the laws of Nature can never 
 be broken without paying the penalty. The man who 
 steps over the side of a cliff, consciously or unconsciously, 
 meets the consequences of his action swiftly, whether 
 he be sinner or saint ; and the laws of health can no 
 more be broken with impunity than can the law of 
 gravitation. When effects follow quickly upon causes, 
 we learn the relationship between them readily, and 
 from our childhood avoid actions which produce pain, 
 as a burnt child dreads the fire. Science has shown 
 
202 DISCOVERY CH. 
 
 that a disease is just as definitely due to a particular 
 cause, preventible or otherwise, though it may not 
 tread closely upon the heels of action. Ignorance of 
 the law may sometimes be pleaded in a court of justice 
 in palliation of an offence ; but Nature accepts no such 
 excuses and decrees a punishment for every crime against 
 her. She never forgives a fault or extenuates it ; inexor- 
 able is her judgment, and inevitable her sentence, 
 which has often to be suffered not only by the offender 
 but also by his children, even to the second and third 
 generations. 
 
 This is a hard saying ; yet it is true, and there is no 
 escape from what it implies. As we have to subscribe 
 to Nature's statutes, it is desirable that our knowledge 
 of them should be as complete as possible. " Give me 
 understanding and I shall keep thy law ; yea, I shall 
 observe it with my whole heart." Where such under- 
 standing does not exist, disease is regarded either as 
 a demon to be exorcised or an " act of God " for which 
 penitence and prayer are remedies. Ignorance made 
 plague the terror of Europe in the Middle Ages ; science 
 has proved that the disease is due to a bacillus which 
 is conveyed by fleas from rat to rat, and from rats 
 suffering from the disease to mankind. Ignorance 
 ascribed malaria to a miasma or bad air arising from 
 marshy places ; science has shown it to be caused by a 
 micro-organism carried from one man to another by a 
 certain species of mosquito. Ignorance of the cause of 
 yellow fever made the regions around the Caribbean 
 Sea the White Man's Grave, where the risk of death for 
 the visitor was greater than in a battle ; knowledge 
 that the disease is associated with a parasite which is 
 communicated from an infected to a healthy person 
 by the bite of a particular mosquito, has been the 
 
vm CONQUEST OF DISEASE 203 
 
 means of converting the same places into tropical health 
 resorts. 
 
 When nothing is known of the natural laws of a disease 
 mankind is helpless against it ; but when science has 
 discovered the enemy a sound basis can be secured for 
 a plan of campaign to exterminate it. Plague has to 
 be fought by the destruction of rats where it prevails, 
 as well as by better housing and sanitation ; malaria 
 and yellow fever have to be kept under control by the 
 continual clearance of breeding-places of mosquitoes in 
 infected areas. Administrative measures based upon the 
 teaching of science have practically abolished plague 
 from the cities of Europe, have cleared Havana, the 
 Isthmus of Panama, the West Indies, and Rio de Janeiro 
 of yellow fever, and have made the Roman Campagna 
 almost free from malaria, though formerly few men 
 who went to the district could hope for more than three 
 years of life in it. 
 
 Practical acquaintance with ailments may be obtained 
 by watching the sick and administering drugs, but this 
 clinical experience is not of much use in determining the 
 nature and origin of disease. For centuries, physicians 
 have made their comforting presence felt at the bedside 
 of their patients, but their observations have contributed 
 little to the knowledge of the causes of diseases, the 
 means of conferring immunity, or of providing anti- 
 toxins or chemical antidotes which by their specific 
 action upon the virus of diseases successfully save human 
 beings, as well as the lower animals, from death and 
 incapacitating illness. 
 
 In the struggle against diseases and the discovery of 
 means of stamping them out and preventing their 
 development, we must not look for help to the popular 
 physician, but to the bacteriological or the chemical 
 
204 DISCOVERY OH. 
 
 laboratory where scientific research is being carried 
 on, often under harassing conditions and always 
 with inadequate recompense. The ordinary medical 
 practitioner, like the engineer, makes use of scientific 
 results for the benefit of mankind, but originates little 
 for himself. He is able and practical, good at diagnosis 
 and clever in manipulation, but withal an empiric, 
 wanting in scientific ideals and only very occasionally a 
 contributor to scientific knowledge. 
 
 Every year an immense amount of time, labour and 
 money is consumed in dealing with the effects of the 
 various diseases to which humanity is liable, and in 
 attempts, more or less successful, to cure these effects, 
 while comparatively little is done toward preventing 
 them by the removal of their chief sources or primary 
 causes. The few brilliant examples which show such 
 striking success in the latter direction only serve to 
 throw into more prominent relief the magnitude of that 
 deplorable amount of loss in life, health and wealth 
 which is still waiting to be dealt with. 
 
 It is a truism well recognised by medical men that 
 the soldier has much more to fear from the ravages of 
 disease than from the fire of the enemy. During the 
 South African war, the British Army lost nearly twice 
 as many men from preventible diseases, chiefly typhoid 
 fever, as it did from wounds received in battle. In the 
 Spanish -American war, there were twenty thousand men, 
 or one-sixth of the American force, laid by with typhoid. 
 On the other hand, scientific investigation into the cause 
 of beri-beri which had impaired the efficiency of the 
 Japanese fleet by almost 50 per cent, during previous 
 years resulted in the complete abolition of this disease 
 from the Japanese ships from 1886 to 1893, and not a 
 single case developed during the war with Kussia, amidst 
 
vni CONQUEST OF DISEASE 205 
 
 the floating force of twenty-five thousand men. In 
 this war, the enlightened and educative measures of 
 the Japanese reduced the deaths due to disease to one- 
 quarter of those due to battle. Thanks to the adoption 
 of scientific methods, the incidence of disease in the 
 British army during the great European War has been 
 far lighter than in any previous campaign. The magni- 
 ficent results achieved by attention to the essential 
 principles of sanitation and preventive medicine have 
 disposed we hope for ever of the old saying, " Disease, 
 not battle, digs the soldier's grave." The health of the 
 British Expeditionary Force is not only safeguarded by 
 sanitary precautions, but also protected against typhoid 
 fever by a treatment of inoculation instituted by Sir 
 Almroth Wright. The success of these methods is little 
 short of marvellous. Deaths of British soldiers from 
 typhoid are much less in proportion than in any preceding 
 war, and men fully protected by two inoculations escape 
 punishment by the disease almost without exception. 
 
 The same principles of preventive medicine are 
 applicable with no less success to civil life. What is true 
 of typhoid, cholera, dysentery and malaria, is equally 
 true of smallpox, tuberculosis, yellow fever, scurvy, 
 rabies, plague and diphtheria, and is true also of numerous 
 other common illnesses ; applicable, therefore, to the 
 poverty and distress which result from them. 
 
 Smallpox was formerly looked upon as practically 
 unavoidable by members of the human family. People 
 used to advertise for servants who had got over smallpox 
 in much the same way as we now inquire, before pur- 
 chasing a dog, whether it has had distemper. The 
 difficulty of getting through life without smallpox was 
 expressed in a popular saying very current in Germany 
 in the eighteenth century ; von Pocken und Liebe bleiben 
 
206 DISCOVERY CH. 
 
 nur wenige frei from smallpox and love few remain 
 free. In his History of England, Macaulay, referring to 
 the death of Queen Mary from the disease in 1694 says : 
 
 That disease over which science has since achieved a succession 
 of glorious and beneficial victories was then the most terrible of 
 all the ministers of death. . "the ha^voc of the plague had been 
 far more lapid ; but plague had visited our 'shores only once or 
 twice within ' living memory, and the smallpox was always 
 present, filling the churchyards with corpses, tormenting with 
 constant fears all whom it had not yet stricken, leaving 
 on those whose lives it spared the hideous traces of its 
 power, turning the babe into a changeling at which the mother 
 shuddered, and making the eyes and cheeks of the betrothed 
 maiden objects of horror to the lover. T. B. Macaulay. 
 
 For the different conditions which exist in civilised 
 countries to-day, and for the fact that the fear of small- 
 pox has become almost as remote as the fear of leprosy, 
 we have chiefly to thank Edward Jenner (1749-1823) 
 the apostle of vaccination. Others had vaccinated 
 before Jenner, but he was the first to rouse the civilised 
 world to take an active interest in the subject. Among 
 medical men of all nationalities his name is held in the 
 highest reverence. Jenner, Pasteur and Lister form 
 a triumvirate that has given the human race reason to 
 rise up and call it blessed. 
 
 The value of vaccination as a protection against 
 smellpox was established by Jenner in 1796 ; the 
 principle of the method of protective inoculation was 
 used by Pasteur in conferring immunity of animals from 
 anthrax eighty-five years later ; and Lister was led to 
 introduce the system of antiseptic surgery by the study 
 of Pasteur's investigations. Jenner opened the door 
 to a new realm of remedies for disease ; and we are only 
 now beginning to realise how vast it is and what possi- 
 bilities it offers for the future. 
 
vm CONQUEST OF DISEASE 207 
 
 Jenner was in his teens and in the first stage of his 
 medical education at Sodbury, Gloucestershire, when 
 his attention was directed to the subject of protection 
 against smallpox. A young girl came there for advice, 
 and on smallpox being mentioned she exclaimed, " I 
 cannot take that disease, for I have had cow-pox." 
 She, like other milkmaids in Gloucestershire and else- 
 where, had discovered for themselves that cow-pox 
 was a safeguard against smallpox ; but it required the 
 insight and patient labour of Jenner to transform a 
 piece of folklore into a scientific truth, and make the 
 medical profession all over the world receive it as 
 such. 
 
 When Jenner went to London, at the age of twenty- 
 one, and was entered as a student at St. George's Hos- 
 pital, he mentioned this belief to John Hunter, who gave 
 his pupil this excellent piece of advice : " Do not think, 
 but try ; be patient, be accurate." On returning to 
 his native town of Berkeley to settle down into country 
 practice as a physician, the belief of the young girl at 
 Sodbury, and Hunter's wise words, were ever constant 
 in his mind. To get at the truth of this opinion was his 
 great object ; but it was not until 1780 that he felt 
 sufficient confidence to communicate to a friend his 
 ideas on the subject of propagating the protective cow- 
 pox from one individual to another, and so ultimately 
 staying the plague of smallpox. 
 
 " Gardiner," said Jenner, " I have entrusted a most important 
 matter to you, which I firmly believe will prove of essential 
 benefit to the human race. I know you, and should not wish 
 what I have stated to be brought into conversation, for should 
 anything untoward turn up in my experiments, I should be made, 
 particularly by my medical brethren, the subject of ridicule, for 
 I am the mark they all shoot at." 
 
208 DISCOVERY CH. 
 
 Jenner continued his experiments for another sixteen 
 years before he performed his first inoculation with 
 cow-pox on May 14th, 1796, the subject being a boy, 
 about eight years of age. The boy was afterwards 
 inoculated for the smallpox, and as Jenner predicted, 
 no disease followed. A means of protecting the human 
 race against its greatest scourge had been discovered, 
 and Jenner redoubled his efforts to establish its efficacy. 
 He vaccinated all the poor in the neighbourhood of 
 Berkeley gratuitously, and the success of the method 
 of inoculation soon became widely known. He vacci- 
 nated his own son on three separate occasions, and 
 prejudice against inoculation with cow-pox began to be 
 overcome when two ladies of title Lady Ducie and the 
 Countess of Berkeley submitted their children to it. 
 
 If Jenner had kept the secret of his discovery to him- 
 self, he could have made an immense fortune from it, 
 but he imparted it to the public, and suffered great loss 
 of time and money in answering inquiries which reached 
 him from all parts of the world. He made known his 
 discovery as soon as he had convinced himself of its 
 value, and never for a moment did he hesitate as to 
 whether he might not be a richer man by keeping his 
 information to himself. 
 
 It is scarcely necessary to add that the discovery did 
 not escape the fate which commonly awaits originality. 
 Jenner's views were opposed and misrepresented, the 
 caricaturists of the period drew persons with horns and 
 cows' heads to suggest what might be expected from 
 vaccination, and sermons were preached to show its 
 wickedness. Nothing could, however, prevent the 
 spread of a method which relieved every household of 
 its greatest terror. Marks of distinction soon began to 
 be showered upon the scientific St. George who had rid 
 
viii CONQUEST OF DISEASE 209 
 
 mankind of the dragon of smallpox that had demanded 
 tens of thousands of victims annually. With the 
 Emperor Napoleon, Jenner was a great favourite. On 
 one occasion Napoleon was about to refuse a petition 
 from Jenner to allow two friends to return to England, 
 when Josephine reminded him that the petition was from 
 the discoverer of vaccination. " Ah," said the Emperor, 
 " Jenner, we can refuse nothing to that man." 
 
 In recognition of the national value of vaccination, 
 the House of Commons voted Jenner a grant of 10,000 
 in 1802, and five years later a further grant of 20,000 
 was made to him, the intervening time having strength- 
 ened the general opinion as to the efficacy of vaccina- 
 tion and as to its great benefit to the nation at large. 
 Competent authorities would not now claim that a 
 single inoculation with vaccine lymph is a perfect 
 antidote against smallpox throughout life, but only 
 that it confers a high degree of protection against the 
 disease. Absolute immunity cannot be ensured in all 
 ;ases because of individual differences of the blood and 
 tissues of the human body ; yet with this reservation 
 the practice of vaccination has been completely justified. 
 We owe our deliverance from the fear of smallpox not 
 so much to improved sanitation, or to a natural decline 
 of the disease or acquired immunity from it, as to the 
 protective principle introduced by Jenner. The pro- 
 gress of preventive medicine depends largely upon the 
 application of this principle, which has proved to be of 
 even greater biological value than was anticipated by 
 Jenner or the physicians of his day. 
 
 Many diseases of animals, as well as those of man, are 
 now controlled or conquered by the application of 
 scientific principles. Before science showed the nature 
 of anthrax, and provided the remedy, many thousands 
 
 G.D. O 
 
210 DISCOVERY CH. 
 
 of cattle and sheep died annually from the disease. A 
 formidable yearly tribute had to be paid to this 
 mysterious scourge until enlightenment came through 
 the labours of Robert Koch and Louis Pasteur. 
 
 Koch cultivated a microbe from the blood of an 
 animal that died from anthrax, and he found that when 
 this microbe was inoculated into guinea-pigs, rabbits 
 and mice, they inevitably took the disease. Pasteur 
 proved that the power of conveying anthrax was due 
 to the bacillus, and to it alone ; and, later, he suggested 
 that, by vaccination of animals with the virus, it would 
 be possible to give them the disease in a mild form, and 
 so secure their immunity from fatal attacks. His 
 conclusions met with the usual reception of ridicule 
 from the practical man concerned with the care of 
 cattle ; and the veterinary profession proposed an 
 experiment to test them. Pasteur accepted the chal- 
 lenge, and the conditions of the battle between knowledge 
 and incredulity were drawn up. Sixty sheep were put 
 at his disposal ; twenty-five were vaccinated, by two 
 inoculations, with the attenuated virus of anthrax. 
 Some days later these, and twenty-five others, were 
 inoculated with some very virulent cultures of the 
 anthrax bacillus. Ten sheep underwent no treatment 
 at all. 
 
 " The twenty-five unvaccinated sheep will all perish," 
 wrote Pasteur ; "the twenty-five vaccinated sheep will 
 survive." The result turned out exactly as he had 
 predicted. The sheep which had been vaccinated with 
 a mild form of anthrax, in order to make them more 
 capable of resisting the later inoculation, survived, 
 while those which had not thus been rendered immune, 
 perished. The conclusion of the experiment is one of 
 the most dramatic incidents in the history of science, 
 
viii CONQUEST OF DISEASE 211 
 
 It was arranged that believers and unbelievers in 
 Pasteur's views should meet on June 2, 1881, at the 
 farmyard where the sheep had been placed, there to 
 celebrate a victory or proclaim a failure. 
 
 When Pasteur arrived at two o'clock in the afternoon, at the 
 farmyard of Pouilly le Fort, accompanied by his young col- 
 laborators, a murmur of applause arose, which soon became loud 
 acclamation, bursting from all lips. Delegates from the Agri- 
 cultural Society of Melun, from medical societies, veterinary 
 societies, from the Central Council of Hygiene of Seine et Marne, 
 journalists, small farmers, who had been divided in their minds 
 by laudatory or injurious newspaper articles all were there. 
 The carcasses of twenty- two un vaccinated sheep were lying side 
 by side ; two others were breathing their last ; the last survivors 
 of the sacrificed lot showed all the characteristic symptoms of 
 splenic fever (anthrax). All the vaccinated sheep were in perfect 
 health. . . . The one remaining un vaccinated sheep died that 
 same night. R. Vallery-Radot. 
 
 Pasteur was an exact experimenter, and when the 
 effect of any treatment was under investigation always 
 had untreated or " control " cases side by side with the 
 others for the purpose of distinguishing the difference 
 between the two sets. Lady Priestley relates that on 
 one occasion she told Pasteur of apparently successful 
 experiments made by inoculating sporting dogs with 
 vaccine lymph against distemper. " Ah," said Pasteur, 
 " and the control experiments ? " This control or 
 proof of the efficacy of the inoculation had not been used, 
 and without it the results fall to the ground in the 
 estimation of the great experimenter. 
 
 The method followed by Pasteur in the control and 
 treatment of anthrax were extended by him to that 
 terrifying disease rabies. By his discoveries in this 
 field alone, he earned the eternal gratitude of humanity. 
 He sought first for the specific microbe of the disease, 
 but unsuccessfully. The prevailing view was that the 
 
212 DISCOVERY CH. 
 
 rabic virus was contained in the saliva of the mad 
 animal. Pasteur wished to test this, and inoculated 
 rabbits with saliva from mad dogs, but the results were 
 inconclusive. It was then suggested that the symptoms 
 shown vby an animal or human being suifering from 
 hydrophobia indicated a connection with the nervous 
 system. Pasteur was thus led to use for his inoculations 
 an emulsion of the brain or spinal cord of a rabid animal, 
 instead of the saliva ; and in every case hydrophobia 
 occurred after inoculation. By attenuating the virus 
 and inoculating dogs with it in increasing strengths, he 
 was able to secure for them immunity against the bites 
 of rabid companions, and to find the period of incubation. 
 
 This was his first step in making dogs refractory to 
 rabies by preventive inoculation ; the second was to 
 prevent the onset of rabies in dogs bitten or subjected 
 to inoculation. The period varies from about a fortnight 
 to seven or eight months, but the average length is six 
 weeks. A person bitten by a mad dog was thus haunted 
 for a long period by the anguish of uncertainty as to 
 whether the virus was developing in his system or not. 
 Pasteur believed that if such a person was inoculated, 
 with increasing strengths of the rabic virus during this ! 
 period, beginning within a few hours or days of the bite, 
 the system would be able to resist the onset of the disease 
 at a later stage. He could not test his conviction 
 deliberately by successive inoculations of a human 
 being, but an opportunity of treating an actual case of] 
 hydrophobia by this principle occurred in 1885. 
 
 A young Alsatian boy, Joseph Meister, who had been I 
 badly bitten only two days before by a mad dog, was 
 brought to his laboratory. After careful consideration 
 and consultation with several leading physiologists and 
 physicians, Pasteur decided to apply anti-rabic inocula- 
 
vm CONQUEST OF DISEASE 213 
 
 tion to little Meister. The treatment lasted ten days, 
 during which the boy was inoculated twelve times. 
 It was completely successful ; and an infallible remedy 
 had been found for a dread disease against which all 
 previous measures had failed. The results of the treat- 
 ment of rabies on this principle are now well known, 
 but for several years strong opposition was offered to 
 it by certain people in Great Britain, while at the same 
 time terrified British sufferers from the disease were 
 continually sent to Pasteur for salvation. In scientific 
 circles Pasteur's great advance in the treatment of 
 disease was understood and fully appreciated, but as 
 it had been obtained by means of experiments on animals, 
 it was misrepresented and vilified by opponents of such 
 experiments until its beneficial effects overwhelmed 
 them. 
 
 Experiments made with the noble object of not only 
 increasing human knowledge but also diminishing human 
 suffering are deserving of the highest praise ; yet those 
 who carry on such researches are often assumed to be 
 among the most callous of mankind. Pasteur was one 
 of the most tender-hearted of men. An instance of 
 disinclination to inflict pain was given by Lord Lister 
 in a speech some years ago, in a reference to his work 
 on rabies. It had been established that the introduction 
 of the portion of the brain of a mad dog under the skin of 
 a healthy animal was liable to cause rabies, and, as has 
 been explained, Pasteur had reason to believe that it 
 was principally in the nervous centres that the poison 
 accumulated. He felt a very strong desire to introduce 
 some of the poison into the brain of an animal ; but he 
 was a peculiarly humane man. He never could shoot 
 an animal for sport. He was more humane than the 
 majority of human beings ; and for a long time he could 
 
214 DISCOVERY CH. 
 
 not bring himself to make the experiment of trephining 
 an animal's skull, and introducing some of the poison 
 of rabies into the brain. He was exceedingly desirous 
 of doing this, to establish the pathology of the disease, 
 but he shrank from it. On one occasion, when he was 
 absent from home, one of his assistants did the experi- 
 ment, and when Pasteur came back he told him he had 
 done so. " Oh," said Pasteur, " the poor beast ! His 
 brain is doubtless injured. I am afraid he will be 
 paralysed." 
 
 The assistant went into a neighbouring room and 
 brought in the animal, which was a dog. It came in 
 frisking about, and investigating everything in a per- 
 fectly natural manner ; Pasteur was exceedingly pleased, 
 and though he did not like dogs, yet he lavished his 
 affection upon this particular animal, and petted it, and 
 from that time forth his scruples no longer existed. 
 The pain inflicted by the process of trephining is, in fact, 
 very slight ; yet the operation is sometimes described 
 as hideously painful. 
 
 Although Pasteur may be considered to be the founder 
 of modern methods of scientific investigation of disease, 
 he was one of the most modest of men. At the Inter- 
 national Medical Congress held in London in 1882, he 
 was desired by the Government of the Republic to 
 represent France. Before the Congress, everyone was 
 inquiring whether he had arrived, but no one had seen 
 him until he entered St. James's Hall to attend the 
 opening meeting. The hall was filled to overflowing, 
 but as Pasteur entered he was recognised by one of the 
 stewards, who was leading him to the place reserved for 
 him on the platform, when there was a great outburst 
 of cheers. Perfectly unconscious that the applause was 
 meant for him, Pasteur turned to his two companions, 
 
viii CONQUEST OF DISEASE 215 
 
 his son and son-in-law, and said, with a little uneasiness : 
 " It is no doubt the Prince of Wales arriving ; I ought to 
 have come sooner." " But it is you that they are all 
 cheering," explained the president of the Congress, and 
 the applause was so great that he had to rise and bow to 
 the great assembly. 
 
 Pasteur had not studied medicine, yet he was able to 
 determine the true cause of disease and to discover 
 secrets hidden to physicians throughout the world's 
 history. When in 1860 he was awarded the prize for 
 experimental physiology by the French Academy of 
 Sciences, he wrote to his father : " God grant that by 
 my persevering labours I may bring a little stone to the 
 frail and ill-assured edifice of our knowledge of those 
 deep mysteries of life and death, where all our intellects 
 have so lamentably failed." 
 
 Pasteur's remains rest in a mausoleum at the Institute 
 which bears his name in Paris. Upon the occasion of 
 their interment, the French Minister of Education 
 eloquently remarked :. 
 
 As at the tombs of saints where people saw prodigies accom- 
 plished, so that of Pasteur wiU be enriched by a halo of miracles. 
 At every discovery beneficial to mankind, at every ray of 
 scientific glory which will be added to the aureole of France, the 
 gratitude of the country and of the world will flow to this building, 
 henceforth august in the annals of science, as to the source of 
 ulterior progress. 
 
 The French people honour him above all other men ; 
 and when on one occasion they were asked to name their 
 greatest countrymen, they put Pasteur first, Napoleon 
 second and Victor Hugo third. 
 
 A few years ago diphtheria was one of the most 
 dreaded of the infectious diseases which afflict the human 
 race; to-day, thanks to scientific research, it is the 
 
216 DISCOVERY CH. 
 
 disease which can be treated with the greatest confidence 
 of success. Formerly the medical man standing at the 
 bedside of a child struggling for breath was almost 
 helpless to relieve its anguish except by a dangerous 
 operation ; now he has at his disposal a remedy which, 
 if used quickly enough, extinguishes the disease as surely 
 as water does a raging fire. He used to fight in the 
 dark against an unknown foe, but he now knows the 
 nature of the forces against him, and has a weapon which 
 will vanquish them completely. 
 
 It is scarcely too much to say that of all the infective 
 diseases which trouble mankind, diphtheria stands 
 foremost as the one concerning which our knowledge is 
 the most complete ; and in this knowledge lies the 
 physician's power. The isolation of the specific microbe 
 which causes the disease was accomplished by Loefner in 
 1884. When this virulent bacillus is grown in broth, ifc 
 produces a quantity of a toxin which can be obtained in 
 the form of a clear liquid. Upon injecting the liquid into 
 a horse several times over a period of two or three months, 
 the horse's blood acquires a quality which counteracts its 
 effects ; and the serum obtained from the blood of such 
 an inoculated animal is the basis of the anti-toxin of 
 diphtheria upon which every doctor now depends for 
 the treatment of the disease. It was Behring who first 
 enunciated the principles of toxin and anti-toxin in 
 diseases, and to the studies of Roux we owe the pre- 
 paration of anti-diphtherial serum. 
 
 The result of the use of the serum has been marvellous. 
 In pre-anti-toxin days, one child of every three infected 
 by the disease ended its sufferings in death ; now only 
 one diphtheria case in ten proves fatal, and when the 
 anti-toxin is used on the first day of the disease not more 
 than two or three cases in a hundred succumb to its 
 
vin CONQUEST OF DISEASE 217 
 
 effects. If there were reason for boasting in the sphere 
 of medical science, the array of brilliant discoveries which 
 has brought about this result might be quoted with 
 pride as conquests for humanity, won by much toil in 
 the face of great difficulties. 
 
 Pasteur was the first to realise the significance of 
 micro-organisms in the economy of Nature ; and it was 
 his work which directly inspired Lord Lister to introduce 
 those antiseptic methods in surgery which have made 
 thousands of sufferers bless his name. By his researches 
 on brewing, Pasteur showed that living organisms 
 bacteria unseen to the naked eye, convert the brewer's 
 wort into ale, and that germs which may afterwards be 
 introduced cause the beverage to become sour or bad. 
 Lister saw that germs introduced into wounds in human 
 flesh might be similarly responsible for the fevers 
 and death which usually followed surgical operations 
 in his early days ; and he took measures to prevent 
 their entrance, and thus permit Nature to do her work 
 of healing under favourable conditions. The brewer 
 may himself introduce the cause of souring into the 
 beverage he desires to keep pure ; and the surgeon may 
 likewise infect the patient while endeavouring to relieve 
 him. 
 
 Recognition of the application to surgery of Pasteur's 
 investigations on fermentation and putrefaction induced 
 Lister, in 1865, to make use of antiseptics in the treatment 
 of compound fractures an operation previously attended 
 with the gravest risk, but now, thanks to Pasteur and 
 Lister, performed without any danger of introducing 
 the germs which caused the complications that were the 
 despair of surgeons. Well has it been said that Pasteur 
 and Lister " formed a brotherhood of science labouring 
 to diminish the sorrows of humanity " ; yet the principles 
 
218 DISCOVERY CH. 
 
 taught by both met at first with nothing but opposition 
 or indifference. 
 
 Fifty years ago the slightest surgical operation was 
 attended with great danger, on account of mortification 
 of the wound and blood-poisoning due to the introduction 
 of putrid matter into the body. By a long and system- 
 atic investigation of the causes of the inflammation 
 which followed injuries to living tissues, Lister was able 
 to show that the danger which formerly existed could 
 be avoided, and by so doing he founded modern surgery. 
 When he commenced his experiments, the healing of 
 injuries or wounds after an operation could not by any 
 means be confidently expected as it can at the present 
 time. It was almost impossible to avoid inflammation 
 and festering of the parts affected, and the wound-fevers 
 which usually followed were the despair of surgeons. 
 
 Lister came to the conclusion that all the putrefactive 
 changes to which wounds were subject, and which send 
 to the grave so many patient sufferers, were due to the 
 presence of bacteria. To prevent this action, he 
 developed a system of careful disinfection of everything 
 which came into direct or indirect contact with a wound. 
 He invented also an antiseptic dressing which excluded 
 bacteria from the wound and assisted the natural 
 tendency of tissues to heal themselves. The results 
 obtained since Lister's methods were introduced in the 
 seventies of the nineteenth century are astounding in 
 their success. To-day, thanks to his careful scientific 
 work, surgeons are able to carry out the most difficult 
 operations without any fear of the terrible mortality 
 which troubled those of a past generation. Thousands 
 of people alive and happy at the present time owe their 
 lives and their relief from suffering not so much to the 
 skill of a surgeon as to the knowledge of the means 
 
vm CONQUEST OF DISEASE 219 
 
 of preventing inflammation by methods indicated by 
 Lister's work. 
 
 At the present time there is scarcely a hospital in the 
 civilised world where the principles of antiseptic surgery 
 are not carried out, not a household which has not in some 
 measure benefited by it, not a medical man who is 
 unaware of its meaning. The amount of prevention of 
 suffering and the prolongation of life due to it are 
 altogether incalculable. 
 
 At the International Medical Congress at Amsterdam 
 in 1879, Lister's appearance called forth the greatest 
 ovation ever witnessed at one of these assemblies. As 
 the applause subsided, the president of the Congress 
 stepped forth and said : " Professor Lister, it is not 
 only our admiration which we offer you ; it is our 
 gratitude, and that of the nations to which we belong." 
 
 At the close of the nineteenth century it was asserted 
 that " Listerism " had saved more human lives than 
 all the wars of the expiring century had sacrificed. 
 " My Lord," said the American Ambassador, in pro- 
 posing his health at a Royal Society banquet, "it is 
 not a profession, it is not a nation, it is humanity itself 
 which, with uncovered head, salutes you." 
 
 Of Lister's tender-hearted nature and love of children, 
 one of his Glasgow students relates the following story : 
 
 One day when Lister was visiting his wards in the Glasgow 
 Royal Infirmary, there was a little girl whose elbow- joint had 
 been excised, and this had to be dressed daily. Lister undertook 
 this dressing himself. The little creature bore the pain without 
 complaint, and when finished she suddenly produced from under 
 the clothes a dilapidated doll, one leg of which had burst, 
 allowing the sawdust to escape. She handed the doll to Lister, 
 who gravely examined it, then, asking for a needle and thread, 
 he sat down and stitched the rent, and then returned the dolly 
 to its gratified owner. 
 
220 DISCOVERY OH. 
 
 Lister died in February, 1912, and by his wish he was 
 laid to rest by the side of his wife in West Hampstead 
 Cemetery. An impressive funeral service was, however, 
 held at Westminster Abbey ; and at it an anthem was 
 sung composed for the funeral of Queen Caroline, in 
 1737, and chosen for the special appropriateness of the 
 words, which were : 
 
 When the ear heard him, then it blessed him ; and when the 
 eye saw him, it gave witness of him. He delivered the poor 
 that cried ; the fatherless and him that had none to help him. 
 Kindness, meekness, and comfort were in his tongue. If there 
 was any virtue, and if there was any praise, he thought on those 
 things. His body is buried in peace, but his name liveth ever- 
 more. 
 
 Pasteur's experiments on dogs, which led to the dis- 
 covery of a remedy for rabies, and most of the operations 
 performed by Lister and his successors, would not have 
 been possible without the use of chloroform. Anaes- 
 thesia is the handmaid of surgery ; it permitted many 
 new departures and rendered operations feasible which 
 had been undreamed of before. Pasteur had a great 
 horror of useless suffering, and always insisted upon 
 anaesthesia before undertaking the trephinings which 
 his experiments involved. It is essential that conscious 
 pain should be avoided in all such operations, whether 
 on animals or man. The anguish endured by patients 
 undergoing operations before the days of anaesthetics 
 has been vividly described by Dr. George Wilson. Dr. 
 Wilson had to undergo the protracted and painful 
 experience of having one foot removed by surgeons. 
 
 " During the operation," he says, " in spite of the pain it 
 occasioned, my senses were preternaturally acute. I watched 
 all that the surgeons did with a fascinated intensity. Of the 
 agony it occasioned, I will say nothing. Suffering so great as 
 I underwent cannot be expressed in words, and thus fortunately 
 
vin CONQUEST OF DISEASE 221 
 
 cannot be recalled. The particular pangs are now forgotten; 
 but the black whirlwind of emotion, the horror of great darkness, 
 and the sense of desertion by God and man, bordering close upon 
 despair, which swept through my mind and overwhelmed my 
 heart, I can never forget, however gladly I would do so." 
 
 Now, in the words of Oliver Wendell Holmes : " The 
 fierce extremity of suffering has been steeped in the 
 waters of forgetfulness, and the deepest furrow in the 
 knotted brow of agony has been smoothed for ever." 
 
 The bust of Sir James Young Simpson in Westminster 
 Abbey bears the inscription : " To whose Genius and 
 Benevolence the world owes the Blessings derived from 
 the Use of Chloroform for the Belief of Suffering." When 
 a young medical student, Simpson was so greatly 
 distressed by the groans of a woman under an operation 
 that he thought of relinquishing his career for work in 
 which he would not meet so much suffering. After 
 reflection, however, he decided to continue his studies 
 with the problem ever on his heart and mind how the 
 pains to which humanity is subject could be relieved. 
 When lecturing to his students in later years, he never 
 wearied in insisting that " the proud mission of the 
 physician is distinctly twofold viz., to alleviate human 
 suffering as well as to preserve human life." It was this 
 noble motive which made him eager to adopt any method 
 of surgical anaesthesia and to carry on systematic 
 experiments and inquiries with the object of finding an 
 aid to painless surgery. 
 
 Before Simpson proved the power of chloroform to 
 put man into a deep sleep, several anaesthetics had been 
 used for this purpose. While working at the Pneumatic 
 Institution in Bristol near the end of the eighteenth 
 century, Sir Humphry Davy discovered the intoxicating 
 and stupefying action of nitrous oxide, and suggested 
 
222 DISCOVERY OH. 
 
 its use in surgical operations. Nearly half a century 
 later Dr. Horace Wells, an American dentist, had one 
 of his upper teeth extracted without any pain after 
 deeply breathing this gas. A later experiment at the 
 Boston Medical School and Hospital was, however, 
 unsuccessful owing to an insufficient quantity of the gas 
 being used, and the failure appears to have discouraged 
 Dr. Wells. His former pupil and partner, Dr. W. T. G. 
 Morton, of Boston, then took up the subject, and was led 
 to the use of sulphuric ether as an anaesthetic. In 
 September, 1846, he extracted a tooth without pain 
 while the patient was breathing sulphuric ether, and in 
 the following month a severe operation was performed 
 painlessly under the gas at the Boston Hospital. 
 
 More than four years earlier, in March. 1842, Dr. C. W. 
 Long, then of Jefferson, Jackson County, U.S.A., had 
 used sulphuric ether as an anaesthetic during minor 
 operations, but he took no steps to make his discovery 
 known, and the new era in anaesthetics and in surgery 
 opened with Dr. Morton's work. Within a few weeks 
 the vapour of sulphuric ether had been used successfully 
 in several other cases of surgical operation in Boston. 
 So soon as the news reached Edinburgh, Simpson was 
 eager to prove the virtue of the new anodyne to relieve 
 the agonising pains of women in travail. He entered the 
 field immediately, and, selecting a difficult case for 
 experiment, proved in January, 1847, that the sufferings 
 of the mother during childbirth could be alleviated by 
 the inhalation of ether- vapour, and that the use of the 
 anaesthetic was not injurious to the child. 
 
 Simpson was not satisfied, however, that sulphuric 
 ether was the best agent for producing anaesthesia. 
 He obtained a number of other volatile liquids, and tested 
 them systematically with the object of finding an anodyne 
 
vin CONQUEST OF DISEASE 223 
 
 as potent as ether but less irritating and disagreeable to 
 the patient. With his two assistants, Dr. Keith and 
 Dr. Duncan, he tried the effect of various liquids night 
 after night, though the tests were not without great 
 risk to the experimenters. The discovery of the power 
 of chloroform has been told dramatically by Prof. Miller : 
 
 Late one evening it was the 4th of November, 1847 on 
 returning home after a weary day's labour, Dr. Simpson, with 
 his two friends and assistants, Drs. Keith and J. M. Duncan, 
 sat down to their somewhat hazardous work in Dr. Simpson's 
 dining-room. Having inhaled several substances, but without 
 much effect, it occurred to Dr. Simpson to try a ponderous 
 material, which he had formerly set aside on a lumber-table, 
 and which, on account of its great weight, he had hitherto 
 regarded as of no likelihood whatever. This happened to be a 
 small bottle of chloroform. It was searched for and recovered 
 from beneath a heap of waste paper. And, with each tumbler 
 newly charged, the inhalers resumed their vocation. Immedi- 
 ately an unwonted hilarity seized the party, they became bright- 
 eyed, very happy and very loquacious expatiating on the 
 delicious aroma of the new fluid. . . . But suddenly there was 
 a talk of sounds being heard like those of a cotton- mill, louder 
 and louder ; a moment more, then all was quiet, and then a 
 crash. On awakening, Dr. Simpson's first perception was mental 
 " This is far stronger and better than ether," said he to him- 
 self. His second was, to note that he was prostrate on the floor, 
 and that among the friends about him there was both confusion 
 and alarm. 
 
 The inhalation of chloroform was repeated many 
 times that night, and ten days later, Simpson was able 
 to announce that he had administered the anaesthetic 
 to about fifty individuals " without the slightest bad 
 result of any kind." Much opposition was at first 
 offered to the use of chloroform in childbirth, largely 
 upon the grounds of the penalty pronounced upon Eve 
 for her transgression in the Garden of Eden " in sorrow 
 shalt thou bring forth children," but it was met with the 
 
224 DISCOVERY CH. 
 
 apt reply by Simpson that " the Lord God caused a deep 
 sleep to fall upon Adam " before taking a rib from him 
 to make a woman for his mate. It was not, however, 
 until Queen Victoria had herself taken chloroform 
 during a confinement that the clamour of a section of 
 the clergy began to give way before the voice of wisdom 
 and experience. 
 
 It is difficult to understand the mind that seeks for 
 Biblical justification of scientific achievement or applica- 
 tion. People who manifest it are like those of the 
 Middle Ages who attributed all disease to some special 
 outpourings of divine wrath on account of human 
 iniquities, and looked for relief from it to prayer instead 
 of works. In this way was the Black Death, or plague, 
 . regarded in medieval times, and only in 1894 was its 
 cause discovered by two Japanese doctors, Yersin and 
 Kitasato, to be a particular parasite which grows in 
 bodies of rats and like animals. The disease is conveyed 
 from rats to human beings by the bites of fleas which 
 have fed upon the blood of rats containing the parasite. 
 For three thousand years " the pestilence that walketh 
 in darkness " took its toll of human beings without 
 being discovered, but now that its true nature is known 
 the human race has in its own hands the means of eman- 
 cipation from the disease. The chain which connects 
 microbe and man in the plague-stricken has been revealed, 
 and by breaking it humanity can be delivered from a 
 thraldom under which it has groaned for unknown ages. 
 
 A few years ago mosquitoes, flies, ticks, fleas and 
 related biting and blood-sucking insects, were considered 
 by most people to be unworthy objects of serious study, 
 but it is now known that they are most important 
 factors in the spread of various diseases, especially in 
 tropical countries, It has been established by many 
 
Photo. Fi-atclli Alinari, Florcnu: 
 
 VI. SCIENCE. 
 
 Statue by Giovanni da Bologna, (1524-1608), 
 in the Palazzo dell' Universita, Genoa. 
 
vm CONQUEST OF DISEASE 225 
 
 investigators that these creatures are the sole agents 
 of inoculation into man of the germs of malaria, 
 yellow fever, sleeping sickness, plague, East-coast fever, 
 Kala-azar, typhus fever, recurrent fever and other 
 maladies which have brought suffering and death to 
 millions of people. In most cases they are not merely 
 mechanical bearers of disease germs from one victim to 
 another, for if that were so the problem of discovering 
 the part they play would be relatively simple. Usually 
 their bodies are breeding-places of microscopic organisms 
 which they suck from the blood of one victim beast or 
 man and these parasites, after undergoing profound 
 transformations within their hosts, are afterwards 
 injected into other victims. Insects have thus been 
 shown to be intimately related to the life of man ; and 
 a branch of study which was formerly considered to be 
 of purely zoological interest has proved to be closely 
 connected with practical problems of European colonisa- 
 tion in tropical regions. 
 
 If it is better to save life than to destroy it, then laud 
 and honour should be given to those patient scientific 
 investigators whose studies have shown how to lessen 
 human suffering and prevent the spread of fatal diseases. 
 Before a disease can be prevented it must be under- 
 stood ; there must be a knowledge of its nature and 
 mode of transmission if a sure remedy is to be found, 
 and that knowledge is obtained by the man of science, 
 whose work meets with little encouragement either 
 officially or publicly, and is usually without reward. 
 
 No better examples could be found of the benefits 
 of such work to the human race than are afforded by 
 the studies of tropical and other diseases carried on in 
 recent years. Perhaps the most important of these 
 diseases is malarial fever, which causes the death of 
 
 G.D. P 
 
226 DISCOVERY OH. 
 
 more than a million people yearly in India alone. When 
 Sir Ronald Ross was carrying out at Bangalore the 
 intricate and minute researches required to determine 
 the cause of malaria and its remedy, he wrote the 
 pleading lines : 
 
 In this, Nature, yield, I pray, to me. 
 
 I pace and pace, and think and think, and take 
 The fever'd hands, and note down all I see, 
 
 That some dim distant light may haply break. 
 
 The painful faces ask, can we not cure ? 
 
 We answer, No, not yet ; we seek the laws. 
 O God, reveal thro' all this thing obscure 
 
 The unseen, small, but million-murdering cause. 
 
 At that time it was believed by most people that 
 malaria was caused by some kind of vapour or " miasma " 
 which rose from swampy or marshy land. It is now 
 known to be transmitted by a certain kind of mos- 
 quito which can harbour the germs of the disease and 
 convey them from one person to another. 
 
 This conclusion seems simple enough, but it was only 
 proved to be true by slow steps and persistent work. 
 The theory that mosquitoes are carriers of disease, and 
 that malaria is transmitted by them or flies, was put 
 forward fourteen centuries ago, and was revived in more 
 modern times, but systematic practical study was 
 necessary to establish it. The links of evidence by which 
 the mosquito has been convicted of causing many millions 
 of deaths from malaria were not forged together until 
 recent years. 
 
 First, Dr. C. L. A. Laveran, a French army surgeon, 
 studying malaria in a military hospital in Algiers, dis- 
 covered that the blood of a person suffering from malaria 
 always contains a peculiar parasite or organism. Sir 
 Patrick Manson then suggested that these parasites pass 
 
viii CONQUEST OF DISEASE 227 
 
 a part of their existence in the bodies of mosquitoes, 
 which carry them from one person to another. When in 
 the blood of a human being the parasites are in a certain 
 stage of development, but they can only complete their 
 life-cycle in the body of their insect host. 
 
 To Sir Ronald Ross belongs the honour of tracing the 
 various stages of the existence of the parasite in the 
 body of the mosquito until it was ripe for injection into 
 a human being by the bite of the insect. He proved by 
 numerous experiments that the only means by which 
 a healthy person can acquire malaria is by the bite of a 
 mosquito which has previously bitten someone whose 
 blood contains the particular organisms associated with 
 the disease. In other words, if there were no mosquitoes 
 of the kind required by the malarial parasites to com- 
 plete their life-cycle, there could be no malarial fever. 
 On the eve of this remarkable discovery, Ross offered 
 up a prayer of thanks which makes a beautiful supple- 
 ment to the lines written several years before : 
 
 This day relenting God 
 
 Hath placed within my hand 
 A wondrous thing ; and God 
 
 Be praised. At His command, 
 
 Seeking His secret deeds, 
 
 With tears and toiling breath, 
 I find thy cunning seeds, 
 
 O million-murdering Death. 
 
 I know this little thing 
 
 A myriad men will save. 
 Death, where is thy sting ? 
 
 Thy victory, Grave ? 
 
 The cause of the disease having been found, the remedy 
 was evidently to stamp out the mosquito, so far as 
 possible, by searching out its breeding-places and 
 
228 DISCOVERY CH. 
 
 destroying the larvae in them. This is not so difficult 
 as it may appear at first sight, because the larvae can 
 easily be distinguished in the puddles and other collec- 
 tions of stagnant water in which they occur. By carrying 
 on a vigorous campaign against mosquitoes, many very 
 malarious places on the earth have been made habitable, 
 and prosperous townships are growing up in districts 
 which formerly sustained only a few sickly and miserable 
 inhabitants. 
 
 Where the teachings of science have been followed, 
 our race has triumphed over its enemies ; where ignor- 
 ance or apathy prevails, the toll is being paid in human 
 lives. This is exemplified not only by malaria, but also 
 by many other diseases which have been studied by 
 scientific methods. During the Spanish- American war 
 the American troops suffered great losses from yellow 
 fever. Inspired by Ross's work, an investigation of 
 the cause of the disease was undertaken, with the result 
 that, like malaria, it was found to be transmitted by a 
 mosquito, though a different kind from that which 
 conveys malaria. 
 
 In the year 1900, the president of the United States 
 appointed a commission of five, with Dr. Walter Reed 
 at its head, to carry out investigations in the Island of 
 Cuba, with the object of discovering the cause of yellow 
 fever. Believing that the mosquito theory could only 
 be tested by actual experiment upon a human subject, 
 one of the members of the commission, Dr. Lazear, 
 permitted himself to be bitten by a mosquito which 
 had previously bitten a person suffering from yellow 
 fever ; with the result that he contracted the disease 
 and died in a few days. He gave up his life for others, 
 and the plain record of his sacrifice upon a tablet erected 
 to his memory reads : " With more than the courage 
 
vni CONQUEST OF DISEASE 229 
 
 and devotion of the soldier, he risked and lost his life 
 to show how a fearful pestilence is communicated and 
 how its ravages may be prevented." 
 
 Two private soldiers volunteered their services for 
 experimental purposes, though they were warned of the 
 danger and suffering probably involved. When both 
 made it a stipulation that they should receive no 
 pecuniary reward, Dr. Keed touched his cap and said 
 respectfully, " Gentlemen, I salute you." For one of 
 the first experiments, three brave men slept for twenty 
 nights in a small ill-ventilated room screened from 
 mosquitoes but containing furniture and clothing which 
 had been in close contact with yellow-fever patients, 
 some of whom had died from the disease. None of the 
 men contracted yellow fever, thus indicating the disease 
 was not of a contagious nature. The next experiment 
 was to divide a similar building by a wire screen, and to 
 admit mosquitoes which had bitten yellow-fever patients 
 into the section on one side only of the screen. One of 
 the soldiers, John J. Moran, entered this section a few 
 minutes later and allowed these mosquitoes to bite him. 
 He had a sharp attack of yellow fever, while three 
 soldiers on the other side of the screen, being protected 
 from mosquito bites, remained in perfect health ; it 
 had been demonstrated that the scourge of the tropics 
 was conveyed by the agency of a mosquito. 
 
 In the same year the Liverpool School of Tropical 
 Medicine sent Dr. H. E. Durham and Dr. Walter Myers 
 to Para to study yellow fever there. Both fully under- 
 stood the dangers to which they would be exposed and 
 the risks they ran, but they decided to take the risks 
 and do the work that came to their hand. Both con- 
 tracted the disease, and Myers died from it a victim 
 to his love of science and humanity on January 20, 
 
230 DISCOVERY OH. 
 
 1901. His death added another name to the roll of 
 martyrs to scientific investigation. High courage and 
 an unselfish spirit led him to accept the invitation to 
 take part in a most dangerous expedition ; and he died 
 that others might live. 
 
 One practical result of the discovery of the cause of 
 yellow fever was that it made possible the construction 
 of the Panama Canal, which had been abandoned as 
 hopeless. It was not a hostile army or political diffi- 
 culties that obstructed the progress of the work, not 
 mountain chain or desert waste, but an insect which 
 raised a barrier of disease and death between endeavour 
 and accomplishment. 
 
 For four centuries the narrow Isthmus of Panama was 
 regarded as the white man's grave. " Yellow Jack," 
 or yellow fever, prevented Spaniards, French, or English 
 from founding colonies there, and it was abandoned to 
 negroes and half-breeds, who were immune to the disease. 
 When Ferdinand de Lesseps, the constructor of the 
 Suez Canal, commenced to cut the canal through the 
 Isthmus of Panama, the chief obstacles in his way were 
 yellow and malarial fevers. His men died like flies. 
 It has been stated that before the work was finally 
 abandoned by the French, a human life had been 
 sacrificed for every cubic yard of earth excavated. 
 Out of every hundred men employed upon the work, 
 at least eighteen were sacrificed to a disease which is 
 now known to be preventable, and many more were 
 rendered helpless. 
 
 When the United States took over the control of the 
 canal, the Government set to work to exterminate 
 the mosquitoes responsible for the transmission of 
 yellow fever and malaria. An army of sanitary officers, 
 organised by Colonel W. C. Gorgas, was employed in a 
 
vm CONQUEST OF DISEASE 231 
 
 vigorous fight against the death-dealing mosquito, with 
 the result that yellow fever has been practically stamped 
 out. Death from yellow fever on the Isthmus of Panama 
 since 1905, when the canal zone came under the complete 
 control of the United States, is almost unknown. By 
 the destruction of a little grey gnat, a great engineering 
 enterprise was made possible of realisation. 
 
 Wherever steady war has been waged upon the mos- 
 quito, yellow fever and malaria have practically dis- 
 appeared. Formerly, yellow fever was the constant 
 scourge of the West Indian Islands. One writer 
 says : " The churchyards of Barbados and the other 
 islands are full of the bones of the victims ; and it is 
 said of the slopes of the Morne, in St. Lucia, that there 
 is not a square yard without the remains of a soldier 
 under it, more being there from the results of yellow 
 fever than from the bullets of the enemy." Now what 
 do we find ? The scourge which terrified the inhabitants 
 of the West Indies every year in the old days has 
 entirely vanished as the result of establishing regulations 
 dealing with the breeding-places of mosquitoes. Action 
 founded upon the word of science has converted into 
 health resorts districts in which formerly a European 
 could scarcely hope to survive. 
 
 Malaria and yellow fever have thus been formidable 
 barriers to colonisation ; and to have discovered their 
 cause and their remedy is of the highest importance to 
 the human race. Let us give one more instance of a 
 similar kind. In certain districts of Central and Southern 
 Africa thousands of cattle and animals die yearly of 
 what is known as fly disease. This disease is carried 
 from a sick to a healthy animal by the bite of a tsetse-fly 
 an insect only slightly larger than an ordinary house- 
 fly. Domestic animals which enter fly-districts are 
 
232 DISCOVERY OH. 
 
 seized in the course of a few days with fever and wast- 
 ing, and they almost invariably die. Books of African 
 travel are full of records of horses, teams of oxen, and 
 herds of native cattle having been destroyed by the 
 tsetse-fly disease ; and on one occasion a native army, 
 proceeding to the attack of an enemy, was effectually 
 routed by having incautiously crossed fly-country. 
 
 Scientific investigations carried on chiefly by Sir 
 David and Lady Bruce have shown that sleeping-sickness, 
 which has destroyed millions of human beings in Central 
 Africa, is probably spread by the bite of a tsetse-fly 
 closely related to that which causes the fly-disease in 
 cattle. Though the suffering caused by sleeping-sickness 
 has been known for many years, it was not until toward 
 the end of the nineteenth century that a systematic 
 study of its cause was undertaken. It was soon found 
 that the tsetse-fly does not possess a venom of its own, 
 but is the carrier of poison matter. When the fly 
 bites a sick person or animal, it sucks up some of the 
 parasites of the disease. These multiply and persist 
 within the body of the insect, and may be transmitted 
 to every person on whom it feeds during several weeks, 
 and perhaps months. Sleeping-sickness was long sup- 
 posed to be fatal to black races only, but the immunity 
 of the white man from it was disproved by the death 
 in 1907 of Lieutenant Tulloch, who contracted the 
 disease while engaged in investigating it in Uganda, 
 and whose name must be added to the same honourable 
 roll as that upon which the names of Lazear and Myers 
 are inscribed. 
 
 In the case of sleeping-sickness, then, we have a par- 
 ticular insect as the agent for the spread of a particular 
 disease. People who devote attention to the study of 
 insects are usually considered to be concerning them- 
 
viii CONQUEST OF DISEASE 233 
 
 selves with subjects far removed from the ordinary 
 affairs of life ; they may be tolerated, but they are 
 not to be encouraged. But now that biting flies have 
 been shown to be responsible for the transmission of a 
 number of terrible diseases, knowledge which was con- 
 sidered quite useless has proved to be of the greatest 
 importance. There could not be a better illustration 
 of the ultimate value of faithful scientific work. Take 
 this lesson to heart ; whatever is worth doing is worth 
 doing well. Every addition to knowledge is a stepping- 
 stone by which the human race can pass to new regions 
 of discovery. Science asks not for words, but work ; 
 for the patient study of the things before us rather than 
 for dreams and vague speculations. Listen to the 
 trumpet-call of a naturalist and philosopher, whose 
 labours for many years " to search out the secrets of 
 nature by the way of experiment " have made life 
 happier and surer in many parts of the world : 
 
 We must not accept any speculations merely because they 
 now appear pleasant, nattering, or ennobling to us. We must 
 be content to creep upwards step by step, planting each foot 
 on the firmest rinding of the moment, using the compass and such 
 other instruments as we have, observing without either despair 
 or contempt the clouds and precipices above and beneath us. 
 Especially our duty at present is to better our present foothold ; 
 to investigate ; to comprehend the forces of nature ; to set our 
 State rationally in order ; to stamp down disease in body, mind, 
 and government ; to lighten the monstrous misery of our fellows, 
 not by windy dogmas, but by calm science. Sir Eonald Ross. 
 
CHAPTER IX 
 SCIENTIFIC MOTIVE 
 
 No man ever had genius who dad not aim to execute more 
 than he was able. Sir Humphry Davy. 
 
 The pleasure of life is according to the man who lives it, 
 not according to the work or place. Emerson. 
 
 It is no paradox to say that in our most theoretical moods 
 we may be nearest to our most practical applications. 
 Prof. A. N. Whitehead. 
 
 ^ Scientific subjects do not progress necessarily on the lines 
 of direct usefulness. Very many applications of the 
 theories of pure mathematics have come many years, 
 sometimes centuries, after the actual discoveries them- 
 sleves. Prof. A. R. Forsyth. 
 
 In all cases, the structure, habits, instincts, and faculties 
 of living things, from the upward growth of the plumule 
 of the sprouting seed to the moral sense of man, are 
 primarily for the good of other beings than those which 
 manifest them. Prof. W. K. Brooks. 
 
 SCIENTIFIC research may be conveniently divided into 
 two classes one in which the motive is solely the desire 
 to extend the boundaries of knowledge, while in the 
 other the special purpose is to obtain results which 
 have a direct bearing upon problems of manufacture 
 and construction. Explorers on the ship of science go 
 out to discover new lands ; and their spirit is not the 
 same as that which actuates the prospectors who follow 
 them with the intention of making the lands profitable 
 
CH. ix SCIENTIFIC MOTIVE 235 
 
 to themselves and others. Both these classes of pioneers 
 have their proper places in the scheme of progress, but 
 they live in different atmospheres. The scientific 
 investigator must have freedom to follow his own 
 course wherever it may lead, whereas technical research 
 can be organised and definite problems presented for 
 which solutions of direct service to man are sought. 
 The standard of value in one case is that of knowledge 
 only, while in the other it is that of profit or use. The 
 scientific mind seeks to understand Nature ; the engi- 
 neering mind to control her for material purposes. 
 
 Some time ago the votes of the readers of an American 
 periodical Popular Mechanics were taken as to what 
 inventions were considered to be the " seven wonders 
 of the modern world." From a list of numerous inven- 
 tions, seven had to be selected ; and those which received 
 the highest number of votes were : wireless telegraphy, 
 the telephone, the aeroplane, radium, antiseptics and 
 antitoxins, spectrum analysis, and X-rays. Each one 
 of these things had its foundations in purely scientific 
 work and was not the result of deliberate intention to 
 make something of service to humanity. 
 
 Wireless telegraphy has its origin in the work of Clerk 
 Maxwell and Hertz ; the telephone depends upon the 
 principles of magneto- electric induction discovered by 
 Faraday ; Langley's investigations of the resistance of 
 the air to moving bodies led him to construct the first 
 working model of an aeroplane ; radium was isolated 
 by the Curies solely on account of its scientific interest 
 and without any view of its practical value ; Chloroform 
 was discovered by Liebig and Soubeiran ; nitrous oxide 
 or " laughing gas " by Davy, and sulphuric ether by 
 Valerius Cordus ; the principle of antitoxin treatment 
 was established by Pasteur, Roux and Yersin, and the 
 
236 DISCOVERY OH. 
 
 application of it to diphtheria by Behring and Kitasato ; 
 spectrum analysis began with Newton's observations of 
 the decomposition of light by a glass prism, and became 
 a means of discovering the constitutions of the sun and 
 stars by the work of Fraunhofer, Wollaston, Kirchhoff, 
 Lockyer and Huggins ; and X-rays were discovered by 
 Rontgen as a natural consequence of previous investi- 
 gations of Crookes, Hertz and Lenard. 
 
 We are aware, of course, that Marconi made wireless 
 telegraphy a commercial undertaking, that Graham Bell, 
 Edison and others perfected the telephone, and the 
 Wright Brothers constructed the first man-carrying 
 flying machine ; but these developments represent 
 applications or extensions of new knowledge and not the 
 creation of it. A scientific investigator working in a 
 laboratory was in every case the originator of the fact 
 or principle utilised in the production of what a consensus 
 of opinion considers to be the seven greatest achievements 
 of modern times. 
 
 The history of science shows that the greatest advances 
 have alwaj^s been made by men who undertook their 
 inquiries into Nature without thought of proximate or 
 ultimate practical application or pecuniary reward. 
 The best kind of scientific research cannot be carried 
 on in an atmosphere of commercialism, or where personal 
 profit is the end in view. Few people outside purely 
 scientific circles have any clear idea as to the meaning 
 and object of research. 
 
 The object may be purely visionary, as was the object of the 
 early chemists and alchemists, whose operations, extending 
 through the dark centuries of the Middle Ages, left behind 
 practically nothing but an extensive, though barren, literature, 
 the witness of the credulity and ignorance of those times. The 
 lesson to be derived from the whole of this strange history is 
 
ix SCIENTIFIC MOTIVE 237 
 
 one which needs to be continually revived and set in the new 
 light of modern discovery and invention. The lesson is simply 
 that until men began to observe and interrogate Nature for the 
 sake of learning her ways, and without concentrating their 
 attention on the expectation of useful applications of such 
 knowledge, little or no progress was made. In other words, 
 until a sufficient foundation of pure science has been successfully 
 laid there can be no applied science. Real progress comes from 
 the pursuit of knowledge for its own sake. Sir William Tilden. 
 
 Whether the world recognises it or no, all its material 
 advance has been achieved by men of science. In the 
 arts of sculpture and architecture, in literature, in 
 philosophy, the position gained by Greece two thousand 
 years ago remains the standard of excellence for the 
 moderns, whereas the last fifty years or so have seen 
 more additions to natural knowledge than all the ages 
 before them ; and the result has been not only advance 
 in material welfare and comfort but also in intellectual 
 outlook. The present era will not be remembered in 
 future history for its art, its literature, or its drama, 
 but for its science, by which it is placed in a pre-eminent 
 position. The names of the men who have made this 
 the golden age of scientific discovery do not loom so 
 large to-day in the public eye as those of successful 
 military commanders or popular orators and authors, 
 but future generations will cherish them when the 
 warrior, the politician and the scribe have passed into 
 the limbo of forgotten things. 
 
 Many of the intellectual giants to which the human 
 race will do homage came from the most unexpected 
 places, and the great discoveries they made often in 
 poverty or in the face of other obstacles went 
 unregarded by a world which believes that the business 
 of science is to find out useful things. Poisson, one of 
 a brilliant array of mathematicians, whom France 
 
238 DISCOVERY CH. 
 
 produced a century ago, spent his early life in a hovel. 
 Fourier, Ampere, Arago and Fresnel, were other great 
 Frenchmen who gave glory of the highest kind to their 
 native land, as did their contemporaries, Faraday in 
 England, and Gauss in Germany. Nearly every one 
 of these men was poor and was descended from the 
 " common people." 
 
 This generation of great men, was not students of the 
 past so much as pioneers of the future. They only used 
 traditional machinery when it served their purpose, and 
 were constantly devising new methods of attacking 
 problems relating both to the heavens and the earth. 
 In mathematical works which excite wonder and admira- 
 tion they discussed the motions of the masses forming 
 our planetary system ; they developed the mathematical 
 theory of heat transmission and of light waves ; they 
 led the way into the vast field of electrical industries in 
 which tens of millions of pounds are now invested ; they 
 made it possible for the engineers of our day to do what 
 has been done. 
 
 Such men have always been the ones to open up new fields 
 of industry, and new lines of human thought. Their work 
 must precede the work of the engineer and the inventor. And 
 when any nation has reached such a stage in its existence that 
 scientific discovery is put in the background, and the entire 
 current of work is expended in engineering and business enter- 
 prise, that nation is on the way to the civilisation of China. For 
 the new problems before us are greater than they ever were before. 
 If the pioneers do not appear, all advance will come to an end. 
 Prof. F. E. Nipher. 
 
 National well-being can be secured only when the 
 close relation between it and scientific progress is 
 understood. Discoveries which lead directly to develop- 
 ments of industry and manufacture may almost be left 
 to take care of themselves, and the search for them is 
 
ix SCIENTIFIC MOTIVE 239 
 
 not likely to be neglected, but it is not the case with 
 those for which no immediate use can be seen, yet 
 almost all scientific research comes within that category. 
 This is the kind of research which needs encouragement 
 more than any other, and demands the greatest amount 
 of originality, inspiration and enthusiasm to produce 
 apparently insignificant results. The man who has zeal 
 for work of this kind, who is a born researcher, should 
 be cherished by his country above all others. 
 
 We have any number of practical men, but brain-craft is the 
 master of hand-craft. England needs brain- craft. We want 
 men who cultivate chemistry for its own sake without substratum 
 of utilitarianism. Men whose discoveries, like that of phos- 
 phorus by Brandt, of the electric oxidation of nitrogen by 
 Priestley, of potassium and sodium by Davy, of aniline by 
 Unverdorben, of benzene by Faraday, and of chloroform by 
 Soubeiran, seemed at the time never likely to be of the slightest 
 use to anybody. Sir William Oroolces. 
 
 " La Eepublique n'a pas besoin de savants " the 
 Eepublic has no use for men of science coldly remarked 
 the president of the tribunal of French Kevolutionists 
 which condemned to death the great chemist Lavoisier 
 in 1793. The founder of modern chemistry met his 
 death calmly and with dignity, and his body was placed 
 in an unmarked grave. It was not long, however, 
 before the French people realised that the execution 
 of Lavoisier was a crime against the whole intellectual 
 world. Two years after his life had been sacrificed to 
 the terrorists of the Kevolution, the nation took part 
 in a solemn funeral ceremony; and orations in his 
 honour were publicly pronounced not only by friends 
 who mourned his death, but also by politicians respon- 
 sible for it. " Compared with the growth of science," 
 said Prof. C. S. Minot, " the shiftings of Governments 
 
240 DISCOVERY OH. 
 
 are minor events. Until it is clearly realised that the 
 gravest crime of the French Revolution was not the 
 execution of the King, but the execution of Lavoisier, 
 there is no right measure of values ; for Lavoisier was 
 one of the three or four greatest men France has pro- 
 duced." 
 
 Lavoisier lived for his fellow men ; and he died because 
 he was the champion of the French Academy of Sciences 
 against the National Convention which desired to sup- 
 press it and all the other learned societies of France. 
 Even when the Convention had decreed the destruction 
 of the Academy, he urged the claims of men of science 
 to national consideration. 
 
 " There is not," he said, " an academician who, if he had 
 applied his intelligence and means to other objects, would not 
 have been able to secure a livelihood and a position in society. 
 It is on the public faith that they have followed a career, honour- 
 able without doubt, but hardly lucrative ... if you allow the 
 men of science who composed the defunct Academy to retire to 
 the country, to take other positions in society, and to devote 
 themselves to lucrative occupations, the organisation of the 
 sciences will be destroyed, and half a century will not suffice 
 to regenerate the order. For the sake of the national honour, 
 in the interests of society, as you regard the good opinion of 
 foreign nations, I beseech you to make some provision against 
 the destruction of the arts which would be the necessary conse- 
 quence of the annihilation of the sciences." Sir T. E. Thorpe. 
 
 Scientific discoveries of direct and immediate applica- 
 tion to human affairs rarely spring forth full-grown and 
 clothed, like the goddess Minerva from the head of 
 Jupiter. Their beginnings are usually inconspicuous, 
 and their development slow. As the acorn gives birth 
 to the giant oak, so what seems to be a trivial experiment 
 or observation is often the seed of a great industry. 
 
 Electric telegraphy of every type depends upon the 
 work of men of science of many nations. Volta, an 
 
ix SCIENTIFIC MOTIVE 241 
 
 Italian, discovered in 1800 his voltaic pile by means 
 of which a continuous current of electricity can be 
 produced. In 1819 Hans Christian Oersted, a professor 
 at the University of Copenhagen, observed that when 
 a wire conveying an electric current was placed length- 
 ways over a compass needle, the needle turned aside 
 from it. The discovery was made accidentally in the 
 course of a lecture, but, as in many other instances in 
 the history of science, " such accidents only meet 
 persons who deserve them." The principle of the 
 relationship thus disclosed between electricity and 
 magnetism was worked out in detail by Ampere, the 
 leading French investigator of electricity ; and he 
 suggested that the effect of the current might be used 
 for signalling at a distance. Two German men of 
 science Gauss and Weber established this means of 
 communication upon a short line in Gottingen in 
 1833, and the first magneto-electric telegraph thus came 
 into being out of laboratory experiment and mathe- 
 matical analysis. 
 
 When Oersted published the results of his observations 
 of the influence of an electric current upon a magnet, 
 no one supposed that they could have an important 
 practical value, yet upon his simple experiment the 
 system of electric telegraphy was based. By sending 
 an electric current through a wire, a compass needle 
 can be deflected to one side or the other at the distant 
 end, and the signals thus received can be translated 
 into messages. 
 
 Oersted would never have made his great discovery of the 
 action of galvanic currents on magnets had he stopped in his 
 researches to consider in what manner they could possibly be 
 turned to practical account ; and so we should not now be able 
 to boast of the wonders done by the electric telegraphs. Indeed, 
 no great law in Natural Philosophy has ever been discovered for 
 G.D. Q 
 
242 DISCOVERY CH. 
 
 its practical applications, but the instances are innumerable of 
 investigations apparently quite useless in this narrow sense of 
 the word which have led to the most valuable results. Lord 
 Kelvin. 
 
 There have been many improvements since the early 
 days of electric telegraphy, but they all depend upon 
 magnetic effects produced by electric currents. In 
 electricity, a far fleeter messenger has been found than 
 Puck, who boasted in Midsummer Night's Dream : 
 " I'll put a girdle about the earth in forty minutes." 
 The land wires and submarine cables now devoted to 
 telegraphic service would girdle the earth 250 times, 
 and with the telephone lines the total length is about 
 thirty-three million miles one-third of the distance 
 from the earth to the sun. 
 
 Fourier's work which has been described as a 
 " mathematical poem " on the analytical theory of 
 heat, was published in 1822 long before electric cables 
 were dreamt ofbut it enabled Kelvin thirty years 
 later to attack a problem, the successful solution of 
 which created submarine telegraphy. 
 
 Prof. Joseph Henry in the United States, Ampere in 
 France, and Faraday in England, gave particular 
 attention to Oersted's experiment and its consequences ; 
 and to their work we owe the construction of the electric 
 dynamo by which the current for lighting, traction, and 
 other purposes is now produced. They reasoned that 
 since electricity in motion could disturb a magnet, the 
 reverse should hold good, and a magnet in motion 
 should be able to produce an electric current in a con- 
 ductor near it. Both Henry and Faraday commenced 
 experimenting with the view of creating a current by 
 the action of a magnet, and both eventually succeeded. 
 Jn 1831 Faraday wrote to a friend : "I am busy just 
 
ix SCIENTIFIC MOTIVE 243 
 
 now again on electro-magnetism, and think I have got 
 hold of a good thing, but can't say. It may be a weed 
 instead of a fish that, after all my labour, I may at last 
 pull up." 
 
 A little later Faraday was able to show that when a 
 magnet is brought rapidly near a coil of wire, a slight 
 electric current is induced in the coil. Upon quickly 
 removing the magnet, a momentary current in the 
 opposite direction is created. Here, then, was a means 
 of producing electric current by the expenditure of 
 mechanical energy. All that was required was to set 
 a magnet in rapid motion near a coil of wire properly 
 arranged, and a supply of electricity could be obtained. 
 This was not fully realised, however, until many years 
 after Faraday performed the experiment to which the 
 electric dynamo owes its origin, though scientific men 
 understood the significance of the experiment. " This 
 discovery of magneto- electricity," wrote Tyndall, " is 
 the greatest result ever obtained. It is the Mont 
 Blanc of Faraday's own achievements. He always 
 worked at great elevations, but higher than this he 
 never attained." 
 
 Nearly fifty years elapsed before the discovery was 
 used with commercial success in the construction of the 
 dynamo ; and now as we travel at high speed upon 
 electric railways, and illuminate our streets and homes 
 with electric light, let us remember that we owe these 
 advantages to persistent and purely scientific experi- 
 ments made by Faraday at the Koyal Institution 
 between the years 1824 and 1831. The new era of 
 electrical invention did not have its origin in the engineer- 
 ing workshop but in the scientific laboratory. 
 
 Necessity is not the mother of invention ; knowledge and 
 experiment are its parents, This is clearly seen in the case of 
 
244 DISCOVERY CH. 
 
 many industrial discoveries ; high-speed cutting tools were not 
 a necessity which preceded, but an application which followed, 
 the discovery of the properties of tungsten-chromium-iron alloys ; 
 so, too, the use of titanium in arc lamps and of vanadium in steel 
 were sequels to the industrial preparation of these metals, and 
 not discoveries made by sheer force of necessity. Pro/. W. R. 
 Whitney. 
 
 It would be easy to give many further instances of the 
 foundation of great industries upon results obtained in 
 scientific investigation. Credit is, of course, due to the 
 engineers who convert laboratory experiments into 
 commercial undertakings, and to inventors for making 
 use of scientific results in the production of instru- 
 ments and devices for the convenience and comfort 
 of man; but in both cases they are adapters of new 
 knowledge rather than creators of it. The new field 
 is opened by the man of science, but he is usually 
 forgotten by those who afterwards take possession 
 of it. 
 
 Facts which seem trivial in themselves may be rich 
 in suggestion to the thoughtful mind. From observing 
 the structure of wasps' nests, which are constructed of 
 a papery-like material produced by the insects by the 
 mastication of bits of stick and other vegetable sub- 
 stances, the naturalist, Reaumur, in the early part of the 
 eighteenth century, was led to suggest that wood-fibre 
 should be used for making paper. Out of that observa- 
 tion has arisen the great industry of paper manufacture 
 from wood-pulp, the demand for which is now so immense 
 that it threatens to exhaust the forest resources of the 
 world. 
 
 So long ago as 1755 Priestley observed that when 
 electric sparks pass through air, the nitrogen and oxygen 
 are caused to combine together and form certain com- 
 pounds of these two elements. Not long after, Cavendish 
 
ix SCIENTIFIC MOTIVE 245 
 
 showed that when air treated in this way was absorbed 
 by a solution of caustic potash, the resulting product 
 was saltpetre, or nitrate of potash. This was not an 
 accidental discovery, but a result which was antici- 
 pated from the knowledge that saltpetre is made up 
 of certain definite proportions of potassium, nitrogen 
 and oxygen. 
 
 The practical application of Cavendish's experiment 
 did not come until the beginning of the twentieth 
 century, when the demand for saltpetre or similar sub- 
 stances containing nitrogen in a particular form as one 
 of its constituents had reached such a high value that the 
 artificial production of the salt offered prospects of 
 commercial profit. Nitrogen is part of the constitution 
 of every explosive used until the middle of the nine- 
 teenth century for military purposes, and " villainous 
 saltpetre," which is chemically known as nitrate of 
 potash, was the only source from which it was obtained. 
 Nitrate of soda is a similar substance, but it was known 
 only as a laboratory product until the discovery of great 
 deposits of the salt in an arid region of the Andes in 
 1821. This Chile saltpetre can be converted into nitrate 
 of potash by a chemical process, and thus provides the 
 true saltpetre required for the manufacture of sporting 
 and military powders. 
 
 But the demand for nitrates proceeds from arts of 
 peace as well as from those of war. Nitrogen in some 
 form or other is an essential fertiliser in agriculture, and 
 nitrate of soda has proved to be a most valuable means 
 of increasing the productiveness of the soil. Sir William 
 Crookes pointed out in 1898 that while the average yield 
 of wheat is but 127 bushels per acre, the yield could 
 be increased to 20 bushels by the use of 1 J cwt. of nitrate 
 of soda upon each acre each year. 
 
246 DISCOVERY CH. 
 
 As about two million tons of nitrate of soda are 
 shipped from South American ports annually, there is 
 a prospect of the ultimate exhaustion of the supply. 
 In the earth's atmosphere, however, there is practically 
 an inexhaustible store of nitrogen, and by methods 
 based upon the experiments of Priestley and Cavendish 
 the nitrogen of the air is now being used in the manu- 
 facture of nitrates or other compounds which can take 
 the place of the natural saltpetre. 
 
 In 1828, a Swedish chemist, J. J. Berzelius, whose 
 investigations have been a lamp unto the path of 
 succeeding generations, discovered a rare element to 
 which the name Thorium was given ; he also carried out 
 noteworthy researches on another rare earth Cerium 
 discovered by a German chemist, M. H. Klaproth, some 
 years earlier. Until recent years these substances were 
 rarely mentioned even in text-books of chemistry, and 
 their existence was only regarded as of academic interest, 
 yet, by their use in the manufacture of the incandescent 
 mantle in 1885, they saved coal-gas from being super- 
 seded by electricity. 
 
 The German chemist, Auer von Welsbach, while inves- 
 tigating the rare metals of the thorium group, found that 
 certain compounds became luminous when held in the 
 flame of a Bunsen burner. He dipped a piece of fabric 
 in a solution of a thorium compound and then held it in 
 the Bunsen flame, with the result that the fabric was 
 consumed and a coherent residue of thoria, which gave 
 a bright light, remained. This was the beginning of 
 the incandescent mantle now in common use everywhere. 
 To increase the luminosity of the mantle, a small 
 quantity of some other substance has to be added to the 
 thorium compound ; and by experiment von Welsbach 
 found that the best result is obtained by the addition 
 
ix SCIENTIFIC MOTIVE 247 
 
 of one per cent, of a compound of cerium. The whole 
 industry of the manufacture of incandescent mantles, 
 of which many millions are produced annually, has thus 
 arisen from purely scientific studies of the rare elements 
 thorium and cerium. 
 
 Even the air-gas burner which gives a non-luminous 
 flame suitable alike for rendering an incandescent 
 mantle luminous or for heating purposes, was devised 
 and used for scientific work, and was later adapted to 
 everyday use. The inventor was R. W. von Bunsen, 
 the famous Heidelberg professor to whom chemistry is 
 indebted for important researches in every branch of 
 the science. Sir Henry Roscoe relates how he took to 
 the Heidelberg laboratory in 1853 a sample of the gas- 
 lamp which was used for heating purposes in the 
 chemistry department of University College, London. 
 The lamp consisted of an ordinary argand burner, above 
 which was a cylindrical copper chimney, on the top of 
 which was a disc of wire gauze. By this arrangement 
 a non-luminous flame was obtained, but the temperature 
 was often low, and in other respects the device was 
 unsatisfactory. Bunsen was not satisfied with this 
 lamp, and he said : " Roscoe, I am going to make a lamp 
 in which the mixture of air and gas shall burn without 
 any wire gauze." After making a large number of 
 experiments on the relative size of the openings for gas 
 and air, the Bunsen burner was produced in 1855. The 
 principle of this burner is used in every gas-fire and every 
 incandescent gas-lamp, as well as in numerous forms of 
 air-gas burners employed in various arts and manu- 
 factures. 
 
 Calcium carbide has become a common substance on 
 account of its use in the production of acetylene for 
 house lighting and for motor and cycle lamps, and in 
 
248 DISCOVERY OH. 
 
 oxy-acetylene welding. It provides another example 
 of a substance discovered by scientific experiment 
 before it became an important commercial product. 
 When it was discovered by Frederich Wohler in 1862, 
 and acetylene gas was produced from it, little importance 
 was attached to the fact, partly, perhaps, on account of 
 the great expense of its preparation. During the past 
 few years, however, acetylene has assumed commercial 
 importance owing to the development of the electric 
 furnace constructed by Prof. Moissan in 1892, in which 
 calcium carbide can be produced readily and cheaply 
 from lime and carbon in the form of coke. The dis- 
 covery was made independently by an American chemist, 
 Willson, who was trying to produce metallic calcium 
 by heating a mixture of coke and lime in an electric 
 furnace. By the addition of water, the grey mass thus 
 obtained is rapidly decomposed into acetylene and 
 lime ; and as by various mechanical devices the flow 
 of water upon the carbide can be regulated, a convenient 
 means of producing any quantity of the gas for illumin- 
 ating purposes is obtained. 
 
 In 1895, M. Le Chatelier found that when acetylene 
 was burnt with an equal volume of oxygen gas, a tempera- 
 ture was obtained nearly two thousand degrees Fahr. 
 higher than that of the oxy-hydrogen flame ; and it 
 was suggested that the use of acetylene in blow-pipes 
 would be of great value in the production of high tempera- 
 tures in the laboratory. A few years later such blow- 
 pipes were applied industrially for oxy-acetylene welding 
 of metals, and they are now used in thousands of work- 
 shops for this purpose. There is not a stage in this 
 story of the application of a substance to the service 
 of man but is directly dependent upon laboratory 
 studies in chemistry. 
 
ix SCIENTIFIC MOTIVE 249 
 
 Wtihler, whose discovery of calcium carbide, though 
 forgotten for a generation, laid the foundation of a great 
 industry, was the first chemist to prepare from inorganic 
 materials in the laboratory a substance Carbamide 
 previously known only as a product of vital action. All 
 the complicated chemical bodies which occur in animal 
 and vegetable life consist mainly of the elements carbon, 
 hydrogen, oxygen and nitrogen. About one hundred 
 and fifty thousand organic compounds are now 
 known, and have mostly been produced artificially by 
 chemists. 
 
 This vast development of organic synthesis is due 
 chiefly to the discovery by Prof. August Kekule in 1858 
 of the characteristics of atomic structure of organic 
 compounds. His laws did for organic chemistry what 
 Kepler's laws and Newton's theory of gravitation did 
 for astronomy ; they revealed the system upon which 
 the immense number of natural substances may be 
 built up from a few elements, and enabled chemists to 
 predict the consequences of different arrangements of 
 these elements. As an architect may produce different 
 edifices by the use of a few building stones, so the chemist 
 is able to construct almost numberless compounds from 
 three or four elementary constituents. 
 
 To one untrained in experimental science, nothing can be 
 more uninteresting than a laboratory of organic chemistry. To 
 stand over furnaces on a hot day, it may be, burning minute 
 quantities of white or brown powders in long tubes ; to watch 
 uninviting liquids for crystals which are very slow to appear ; 
 to separate liquids from coloured solids an operation which 
 often interferes with the beauty of the fingers; to inhale 
 odours which may be of the violet or the meadow-sweet, but 
 usually are not all this must be dreary enough to the untrained 
 mind, the mind incapable of responding to the chemist's idea. 
 How different to the chemist. He is trying to unravel the 
 
250 DISCOVERY CH. 
 
 mysteries of the architecture of some molecule. He has an 
 idea which he hopes may do this. He is testing its validity. 
 In the light of this idea, labour otherwise unpleasant seems 
 pleasure, days seem minutes. To succeed is his greatest joy. 
 He may not succeed, but, as it is with sport, he does not know 
 final defeat, but modifies his idea and tries again. Prof. A. 
 Senier. 
 
 During his Easter vacation in 1856, a lad only seven- 
 teen years of age set himself the task of trying to prepare 
 quinine artificially. His name was William Henry 
 Perkin ; and the problem which he faced still remains 
 unsolved, but his experiments led to the discovery of 
 the first aniline dye, and from it has arisen a great 
 industry. In the course of his attempts to make 
 quinine, Perkin obtained a black mass, which would 
 have been left by most students as the final result of the 
 inquiry. But Perkin had the true scientific spirit, and 
 proceeded to investigate this uninviting substance. 
 He obtained from it finally the violet dye known as 
 mauyine or aniline purple. Aniline, from which this 
 dye was derived, is one of the substances found in the 
 tar obtained during the manufacture of coal-gas. In 
 the early days of gas-making, coal-tar was regarded as 
 a waste product of no use to anyone, and often a 
 great nuisance to the manufacturer. It is now known 
 to be a rich mine from which many useful substances 
 can be obtained by chemists, in addition to hundreds of 
 dye stuffs. 
 
 After Perkin's discovery of mauve, numerous other 
 dye-stuffs were produced in quick succession from coal- 
 tar by variations of the process discovered by him ; 
 and there are now several hundreds of similar dyes 
 on the market, all of which owe their origin to his work. 
 Here, then, we have a striking example of a vast indus- 
 trial development being founded upon a result obtained 
 
ix SCIENTIFIC MOTIVE 251 
 
 during a purely scientific investigation. Referring to 
 this, a great chemist once remarked : 
 
 Whenever one of your chemical friends, full of enthusiasm, 
 exhibits and explains to you his newly- discovered compound, 
 you will not cool his noble ardour by asking him that most terrible 
 of all questions, " What is its use ? Will your compound bleach 
 or dye ? Will it shave ? May it be used as a substitute for 
 leather ? " Let him quietly go on with his work. The dye, 
 the leather, will make their appearance in due time. Let him, 
 I repeat, perform his task. Let him indulge in the pursuit of 
 truth of truth pure and simple of truth not for the sake of 
 Mauve let him pursue truth for the sake of truth. Prof. A. W. 
 von Hofmann. 
 
 The discovery of oxygen gas by a poor Swedish 
 apothecary, Scheele, and independently by the English- 
 man, Joseph Priestley, son of a humble cloth-dresser, 
 was one of the most important ever made in chemistry, 
 but more than a century elapsed before practical value 
 was given to it by the use of oxygen with hydrogen in 
 the oxy-hydric process of cutting metals, and in many 
 other arts. Chlorine another gas discovered by Scheele 
 not only influenced the progress of pure chemistry but 
 also now plays an important part in practical affairs. 
 It is used for bleaching straw, paper and other materials, 
 and is essential to the manufacture of chloroform, 
 which could never have been discovered but for Scheele's 
 work. It is used extensively in the chlorination process 
 for the extraction of gold from its ores ; and the noxious 
 green gas first produced with simple apparatus in a 
 little room of an apothecary's shop has thus become a 
 valuable servant of a great industry as well as a diabolical 
 weapon of warfare. One of the deadliest poisons known 
 to chemistry, potassium cyanide, when in dilute solution, 
 will dissolve natural gold ; and here again a laboratory 
 observation has given rise to an important practical 
 
252 DISCOVERY CH. 
 
 process. The chief method now used for the extraction 
 of gold from its ore is the cyanide process, and it enables 
 large quantities of the precious metal to be obtained 
 from residues which in the absence of this process would 
 be waste tailings. 
 
 The first gas ever liquefied was chlorine, and when 
 Faraday succeeded in transforming it by pressure into 
 the liquid state he opened a new era of benefit to man. 
 Liquid air, liquid oxygen, and liquid hydrogen, are all 
 now commercial articles and not scientific curiosities. 
 Large quantities of sulphur dioxide and ammonia in the 
 liquefied form are now used for the artificial production 
 of ice, and for the refrigerating machinery which enables 
 fruit, meat and other articles of food to be transported 
 from their place of origin to distant parts of the earth in 
 a fresh condition. 
 
 Sir James Dewar, working at the Royal Institution, 
 where Faraday made his pioneer experiments on the 
 liquefaction of gases, worthily carried on the work there, 
 and succeeded in reducing the most intractable gases to 
 the solid as well as the liquid form. A device adopted 
 by him for retaining liquid air and other liquefied gases 
 became later an article of commerce in the form of the 
 Thermos or vacuum flask. An instrument devised 
 originally for a scientific purpose has thus been converted 
 into an everyday commodity by which liquids can be 
 kept at a constant temperature for many hours. Before 
 it was generally realised that the vacuum flask had not 
 been patented, certain manufacturers made small for- 
 tunes out of it by charging a guinea for what had 
 cost about a shilling to produce ; but neither then nor 
 later has the actual inventor of this scientific device 
 reaped any pecuniary reward for his ingenuity. 
 
 Saccharin, which has an intensely sweet taste, and is 
 
ix SCIENTIFIC MOTIVE 253 
 
 of great value in cases of diabetes and other disorders 
 in which ordinary cane-sugar has to be avoided in a 
 patient's diet, was discovered in 1879 while an investiga- 
 tion was being carried on in Prof. Ira Kemsen's laboratory 
 that seemed as little likely to lead to practical results 
 as any that could well be imagined. 
 
 Any practical man would unhesitatingly have condemned 
 the work as being utterly useless, and I may add that some did 
 condemn it. There was no hope, no thought entertained by us 
 that anything practical would come of it. But lo ! one day it 
 appeared that one of the substances discovered in the course 
 of the investigation is the sweetest thing on earth ; and then it 
 was shown that it can be taken into the system without injury ; 
 and finally that it can be manufactured at such a price as to 
 furnish sweetness at a cheaper rate than it is furnished by the 
 sugar cane or the beet. And soon a great demand for it was 
 created, and to-day it is manufactured in surprising quantities 
 and used extensively in all corners of the globe. Prof. Ira Remsen. 
 
 Early in the nineteenth century Sir Humphry Davy 
 succeeded in decomposing caustic potash and caustic 
 soda by means of the electric current, and in obtaining 
 from them the metals potassium and sodium. The 
 experiment was made to settle a disputed question in 
 pure chemistry, but it was the starting-point of an 
 immense industry. At the present time, the only 
 process of commercial importance for making sodium 
 is that of electrolysis of caustic soda, all chemical 
 methods of manufacturing the metal being superseded 
 by it. Caustic soda itself, together with chlorine for 
 bleaching purposes, is obtained from common salt by 
 electrolytic methods on a large scale ; and its manu- 
 facture is an important industry. 
 
 In 1833, Faraday obtained the metal magnesium 
 from a compound of the element by means of electro- 
 lysis ; and now the magnesium ribbon and powder 
 
254 DISCOVERY CH. 
 
 used for flash-light and other purposes are almost 
 entirely made by the same method. But the most 
 important application of electricity to industrial chemis- 
 try is the electrolytic production of that most useful 
 metal, aluminium, which is destined to compete with 
 iron and steel in its importance. Aluminium is now 
 manufactured exclusively by electrolysis of a fused 
 mineral containing it, though a few years ago it was 
 obtained wholly by purely chemical methods. Unlike 
 the examples already mentioned, the actual process of 
 producing aluminium by electrolysis was not derived 
 directly from a scientific laboratory, yet it and all other 
 electrolytic methods would never have come into being 
 but for the discovery by men of science of the chemical 
 effects of the electric current. 
 
 Industrial chemistry has, in fact, been revolutionised 
 by the application of electrical methods ; and the 
 foundation of the new branch was laid chiefly by the 
 genius and research of Davy and Faraday, being practi- 
 cally based on the laws enunciated by the latter. 
 Metals, such as copper and iron, are obtained in the 
 highest state of purity by electrolysis ; in the United 
 States alone, more than twenty million pounds' worth 
 of copper are electrically refined every year. Silver, 
 gold and lead are also refined on a large scale by 
 electrical methods. Electro-plating with gold, silver, 
 nickel and other metals ; electrotyping, which is used 
 in every printing works to obtain copies of type and 
 engravers' blocks ; the electrolytic reproduction of 
 medals and similar articles, and a hundred other com- 
 mercial uses have been found for methods which when 
 first discovered were considered to be of interest only 
 to the world of science. It was the remembrance of 
 such facts as these as to the influence of scientific work 
 
ix SCIENTIFIC MOTIVE 255 
 
 upon industrial progress that induced Huxley to remark, 
 so long ago as 1877, in urging the value of technical 
 education : 
 
 I weigh my words when I say that if the nation could purchase 
 a potential Watt, or Davy, or Faraday, at the cost of a hundred 
 thousand pounds down, he would be dirt-cheap at the money. 
 It is a mere commonplace and everyday piece of knowledge that 
 what these men did has produced untold millions of wealth, in 
 the narrowest economical sense of the word. Huxley. 
 
CHAPTEE X 
 PRACTICAL PURPOSE 
 
 Purpose directs energy, and purpose makes energy. 
 C. H. Parkhurst. 
 
 A life without a purpose is a languid, drifting thing. 
 Marcus Aurelius. 
 
 Still o'er the earth hastes opportunity 
 
 Seeking the hardy soul that seeks for her. J. R. Lowell. 
 
 The Time is great 
 
 (What times are little ? To the sentinel 
 That hour is regal when he mounts on guard.) 
 
 George Eliot. 
 
 There are two distinct classes of men : first, those who work 
 at enlarging the boundaries of knowledge, and secondly, 
 those who apply that knowledge to useful ends. Prof. 
 R. W. von Bunsen. 
 
 SCIENTIFIC investigations carried on with the single 
 motive of acquiring new knowledge often lead, as we 
 have seen, to results of great practical value. Such 
 applications are, however, only incidental, and in the 
 world of science they provide no test of the importance 
 of the work done. The practical man judges scientific 
 research from the point of view of its direct service to 
 humanity, or that of money-making capacity ; and he 
 considers that people who devote their lives to studies 
 having neither of these profitable objects in mind are 
 wasting their time and abusing their intellectual 
 faculties, 
 
OH. x PRACTICAL PURPOSE 257 
 
 It comes as a surprise to most men to be told that in 
 scientific circles usefulness is never adopted as the 
 standard of value ; and that even if not a single practical 
 result is reached by an investigation, the work is worth 
 doing if it enlarges knowledge or increases our outlook 
 upon the universe. This proposition, of course, leaves 
 the practical man cold ; yet it is all that science desires 
 to offer in justification of its activities. While the 
 discovery of truth remains its single aim, science is free 
 to pursue inquiries in whatever direction it pleases ; 
 but when it permits itself to be dominated by the spirit 
 of productive application it becomes merely the galley- 
 slave of short-sighted commerce. Almost all the investi- 
 gations upon which modern industry has been built 
 would have been crushed at the outset if immediate 
 practical value had determined what work should be 
 undertaken. Science brings back new seeds from the 
 regions it explores, and they seem to be nothing but 
 trivial curiosities to the people who look for ..profit from 
 research, yet from these seeds come the mighty trees 
 under which civilised man has his tent, while from the 
 fruit he gains comfort and riches. 
 
 Industrial research is concerned not with the discovery 
 of truth but with the production of something which 
 will be of direct service to man and from which pecuniary 
 profit may be secured. It is the province of the inventor 
 rather than that of the man of science. Such research 
 and that carried on with no ulterior motive are com- 
 plementary to one another. Science has done its part 
 when it has made a new discovery ; constructive 
 engineering renders good service when it shows how 
 the discovery may be chained to the chariot of industrial 
 advance. To foresee the possibilities of a discovery, to 
 transform a laboratory experiment into the mechanical 
 
 G.D. R 
 
258 DISCOVERY CH. 
 
 plant of a large works, or to apply it to the needs of 
 ordinary life, require aptitudes not commonly possessed 
 by the scientific investigator. The engineer usually 
 has such practical purposes in mind ; discoveries are 
 to him things to be used and not ends in themselves, 
 as they are to the man of science. He seeks not so 
 much to know Nature as to circumvent her ; and the 
 research which he undertakes or organises has for its 
 object the artificial preparation of substances which 
 are naturally rare, the production of a new process or 
 the improvement of an old, the design of machines 
 which will increase his power over her, and of instruments 
 which will enable him to laugh at limitations of time 
 and space. 
 
 Research is necessary for these advances, but the 
 spirit in which it is carried on is essentially different 
 from that of the scientific worker. The engineer or the 
 inventor first of all perceives a need and then endeavours 
 to devise a -means of meeting it. If he is of a scientific 
 type of mind he will make an accurate analysis of the 
 conditions to be fulfilled, and then design his machine 
 or instrument to fulfil them ; but the usual way is to 
 find practically what will perform the required functions, 
 and to leave experience or scientific knowledge to 
 indicate how improvements may be effected. 
 
 The two methods may be illustrated by the discovery 
 of the safety-lamp for miners. With no access to 
 scientific works, or intercourse with scientific men, 
 George Stephenson constructed a safety-lamp which, 
 like Davy's, depended upon the principle that the flame 
 would not pass through tubes of small diameter and 
 ignite explosive gases outside. Stephenson first made 
 a lamp with a long chimney and a tube at the bottom 
 to admit air for the flame. As this was found to give 
 
x PRACTICAL PUEPOSE 259 
 
 an unsteady flame, he corrected the defect by using 
 several tubes of reduced diameter instead of a single 
 tube, to supply the air. This lamp was found to burn 
 better than the first lamp, and was used with safety in 
 a dangerous mine early in November, 1815. A few 
 weeks later he had a third lamp constructed in which 
 small holes in metal plates took the place of the tubes, 
 but in this device he was forestalled by Davy, who 
 presented to the public on November 9th, 1815, his 
 safety-lamp having wire gauze surrounding the flame. 
 
 It is not our intention, however, to revive the angry 
 controversy which arose over the respective claims of 
 Stephenson and Davy as the discoverer of the miner's 
 safety-lamp ; all we wish to do is to use the invention 
 to illustrate the different methods by which the same 
 end may be reached. Stephenson made a lamp and 
 then proceeded to test and perfect it ; Davy, when he 
 took up the problem of the cause and possible prevention 
 of explosions in mines, first inquired into the nature 
 of the explosive gases and of flame, and was soon able 
 to announce his discovery " that explosive mixtures of 
 mine-damp will not pass through small apertures or 
 tubes ; and that if a lamp or lanthorn be made air-tight 
 at the sides, and furnished with apertures to admit the 
 air, it will not communicate flame to the outward 
 atmosphere." Davy discovered a principle and then 
 constructed a lamp based upon it. Stephenson made 
 a lamp and was led by it to a principle. Though there 
 may be differences of opinion as to who was the inventor 
 of the safety-lamp, the establishment of the principle 
 of its construction was undoubtedly discovered by 
 Davy, and was a notable advance of scientific know- 
 ledge. It was, however, left to practical men to devise 
 the improvements which removed some of the defects 
 
260 DISCOVERY OH. 
 
 of the lamp in its original form, and made it an 
 efficient protection against the dangers of fire-damp in 
 mines. 
 
 The combination of mechanical ingenuity with 
 scientific genius is rare ; two men in whom it was notably 
 manifest were James Watt and Lord Kelvin. Watt 
 was of an inquiring turn of mind from his boyhood. 
 The story is told that, sitting one evening with his aunt, 
 Mrs. Muirhead, the latter said : " James Watt, I never 
 saw such an idle boy ; take a book or employ yourself 
 usefully ; for the last hour you have not spoken one 
 word, but taken the lid off that kettle and put it on again, 
 holding now a cup and now a silver spoon over the steam, 
 watching how it rises from the spout, and catching and 
 connecting the drops of hot water. Are you not 
 ashamed of spending your time in this way ?" Whilst 
 thus blamed for his idleness, his active mind was busy 
 in investigating the properties of steam, and he was 
 then only fifteen years old ! He also busied himself 
 with chemical experiments, repeating them till satisfied 
 of their accuracy from his own observations. As an 
 instance of his versatility in all kinds of instrumental 
 work, he was asked, amongst other things, to make an 
 organ for a Masonic Lodge in Glasgow. A lecturer at 
 Glasgow University wrote to a friend : 
 
 We imagine that Mr. Watt could do anything ; and though 
 we all knew that he did not know one musical note from another, 
 he was asked if he could build this organ. He said, " Yes," but 
 he began by building a very small one for his friend, Dr. Black. 
 ... In doing this a thousand things occurred to him which no 
 organ builder ever dreamed of nice indicators of the strength 
 of the blast, regulators of it, etc. . . . 
 
 Steam had been used to drive engines long before 
 the time when Watt devoted attention to the subject. 
 
x PRACTICAL PURPOSE 261 
 
 More than two thousand years ago, Heron of Alexandria, 
 who with Archimedes stands out from the Greek philo- 
 sophers of his day because of his mechanical ingenuity, 
 invented a kind of steam-engine in which the reactive 
 force of steam escaping from jets on a hollow metal ball 
 caused the ball to spin round. The principle of this 
 engine was similar to that of the steam-turbine which 
 has been developed so remarkably by Dr. de Laval and 
 the Hon. Sir Charles A. Parsons since 1880. Heron's 
 machine, however, was only a toy, and the first successful 
 engine put to practical use was invented by Captain 
 Savery in 1698. This engine was employed for pumping 
 water ; and the principle of its action is the same as 
 that of the modern pulsometer pumps now extensively 
 used. 
 
 The beginning of the steam-engine as we now know 
 it, containing a cylinder into which steam enters, and 
 a piston moving in the cylinder, was the atmospheric 
 engine devised in 1705 by Thomas Newcomen, a black- 
 smith of Dartmouth, England. An overhead beam 
 capable of swinging up and down, like a see-saw, was 
 connected with a piston on one side and with a pump- 
 rod on the other. The piston could move up and 
 down in a cylinder connected to a boiler by a steam- 
 pipe furnished with a valve. When the piston was at 
 the top of the cylinder, steam was admitted, the valve 
 was closed, and a jet of water was caused to play into 
 the cylinder. The steam was thus condensed, leaving 
 a partial vacuum in the cylinder, with the result that 
 the piston was forced down by the pressure of the 
 atmosphere above it ; and as it pulled down one arm 
 of the overhanging beam, the other arm connected with 
 the pump-rod was pulled up. The weight of the pump- 
 rod would then pull down its end of the beam and the 
 
262 DISCOVERY OH. 
 
 piston would thus be brought to the top of the cylinder 
 again, ready for another stroke. 
 
 Watt's constructive work on the steam-engine began 
 after 1757, when he was given a workshop as a mathe- 
 matical instrument maker within the walls of the 
 University of Glasgow. He first tried some experiments 
 on a Papin's digester, which is merely a small sealed 
 iron vessel having a safety-valve, so that water can be 
 boiled in it under a pressure much greater than that of 
 the atmosphere. Watt made a form of steam-engine 
 by fixing upon the digester a syringe one-third of an inch 
 in diameter with a solid piston, and furnished also with 
 a tap to admit the steam from the digester or shut it off 
 at pleasure, as well as to open a communication from 
 the inside of the syringe to the open air, by which the 
 steam contained in the syringe might escape. The 
 steam from the digester forced the piston up, and was 
 allowed to escape ; the pressure of the atmosphere then 
 pushed back the piston to its original position, and 
 the action could be repeated. This single-acting high- 
 pressure syringe engine was made and experimented 
 upon by Watt about 1761 ; and, with certain additions, 
 still constitutes one of the best forms for road motors. 
 
 In 1763-64, Watt had to repair a model of Newcomen's 
 engine belonging to the Natural Philosophy Department 
 of the University of Glasgow. He saw that the alternate 
 heating of the cylinder by steam and cooling it by water 
 involved great loss of heat ; and he set to work to 
 devise a means of remedying this and other defects of 
 the engine. The solution of the chief difficulty occurred 
 to him while taking a walk on a fine Sunday afternoon 
 in 1765. He tells us : 
 
 I was thinking upon the engine at the time, and had gone as 
 far as the herd's house, when the idea came into my mind that, 
 
 
x PRACTICAL PURPOSE 263 
 
 as steam was an elastic body, it would rush into a vacuum, and 
 if a communication were made between the cylinder and an 
 exhausted vessel, it would rush into it, and might be there con- 
 densed without cooling the cylinder. James Watt. 
 
 It must not be supposed, however, that Watt's 
 improvements of Newcomen's engine were due only to 
 a happy thought put into action. He approached the 
 question of perfecting the steam-engine as a scientific 
 problem, and under the inspiration of the principle of 
 " latent heat " discovered by Joseph Black, his friend 
 and guide in the many researches. Black, who was a 
 professor in the University of Glasgow, measured the 
 amount of heat required to transform ice into water 
 and water into steam, and found that a great quantity of 
 heat was used up in each case without producing any rise 
 of temperature. Conversely, when steam is condensed 
 into water, or water is frozen into ice, the change of 
 state involves the liberation of heat. A pound of steam, 
 for example, contains five hundred times more heat 
 than a pound of boiling water. 
 
 Watt discovered, by numerous experiments, that the 
 quantity of heat thus contained in steam was nearly 
 constant for different pressures within the ranges used 
 in steam-engines a conclusion which showed that 
 decided advantage could be gained by using steam at 
 high pressure. He proved also by experiment that, 
 with the Newcomen engine, three-quarters of the heat 
 of the steam was lost in making the cylinder hot at each 
 stroke, and he aimed at lessening this waste of steam 
 and consequently of fuel, with the result that he gave 
 to the world an engine which consumed per horse-power 
 only one- quarter of the fuel previously used by any 
 engine. Though now the consumption of coal per horse- 
 power is only from one-third to one-quarter what it was 
 
264 DISCOVERY OH. 
 
 in Watt's time, yet the advance he made was a most 
 remarkable engineering achievement. 
 
 The principles Watt followed in effecting his improve- 
 ments of the steam-engine were that the cylinder should 
 be kept as hot as the steam that enters it, that steam 
 should be condensed in a vessel distinct from the cylinder, 
 and that the steam itself should move the piston, instead 
 of the pressure of the atmosphere doing it, as was the 
 case with Newcomen's engine. 
 
 Watt's earliest commercial engine (1769) represented 
 the realisation of these principles. The cylinder was 
 clothed with non-conducting materials, and fitted with 
 a steam-jacket in order to keep it hot ; condensation 
 of the steam was effected in a separate condenser, and 
 the piston was pushed down the cylinder by admitting 
 steam above it, the force of the steam thus taking the 
 place of the pressure of the atmosphere in the Newcomen 
 engine. A further improvement was made in 1782, 
 when Watt introduced for the first time the principle 
 of making the steam act alternately on the top and 
 bottom of the piston. The Watt engine, with its many 
 ingenious details of construction, was the prime mover 
 in most general use for eighty years, until the middle 
 of the nineteenth century, when the compound engine 
 and other highly developed forms began to be intro- 
 duced. 
 
 Watt transformed a rude and imperfect steam-engine 
 into an efficient and powerful working instrument, and 
 by so doing accomplished the greatest work performed 
 by any engineer of modern times. He combined the 
 qualities of the practical mechanic with those of the 
 patient investigator, and the perfection to which he 
 brought the steam-engine was due even more to scientific 
 experiment than to mechanical skill. " Nature can 
 
x PRACTICAL PURPOSE 265 
 
 always be conquered," he used to say, " if we can but 
 find out her weak side " ; and this thought encouraged 
 him to persevere in his questioning and attack until 
 the secret he desired to discover was revealed to him. 
 Even after the brilliant idea of separate condensation 
 had occurred to him, he had to work for more than 
 twenty years before he could see that his steam-engine 
 would bring him anything but disappointment and loss, 
 yet he endured unto the end, and saw his engines used 
 in increasing numbers in mines and manufactures. 
 No invention has had a greater influence upon material 
 progress than Watt's engine, and none has been brought 
 to perfection by a closer combination of genius, scientific 
 study and mechanical ingenuity, all of which were 
 blended in one man James Watt, mathematical instru- 
 ment maker to the University of Glasgow. 
 
 Thomas A. Edison is the embodiment of the method 
 of specialised research with a practical purpose. By 
 quickness of perception, fertility of resource, and per- 
 sistent trial of everything until the best means of 
 achieving his end has been found, he has become the 
 leading inventor in the world. When he was endeavour- 
 ing to find the best material to use for the filament of 
 the incandescent electric lamp, he dispatched agents to 
 search through China and Japan, to explore the American 
 continent from the Atlantic to the Pacific, and to seek 
 in India, Ceylon and the neighbouring countries for a 
 vegetable fibre which could be carbonised most effi- 
 ciently ; and he finally used a strip of carbonised 
 bamboo for the filament. He invented the phonograph 
 in 1877, and from the rough instrument then devised 
 developed the perfect means of recording and repro- 
 ducing sound represented in the modern form of talking 
 machines. He constructed new forms of transmitter 
 
266 DISCOVERY OH. 
 
 and receiver of telephones, and from his fertile brain 
 have come a system of multiple telegraphy, new methods 
 of treating ores and many other agents for the service 
 and pleasure of man. 
 
 The phonograph and the kinematograph are, perhaps, 
 the greatest of Mr. Edison's achievements, both in a 
 scientific and in a popular sense. He was not the first 
 to photograph and combine a series of moving pictures, 
 but he was the inventor of the instrument by which 
 this is now accomplished. So long ago as 1870, Dr. E. J. 
 Marey in France, and a little later Mr. E. Muybridge in 
 the United States, began the analysis of animal move- 
 ments by means of photographs taken at very short 
 intervals. A few years afterwards, Mr. Muybridge 
 arranged successive pictures on glass discs, and by 
 rotating them in front of an optical lantern he was able 
 to produce the visual impression of motion. 
 
 The invention of the celluloid ribbon enabled pictures 
 to be taken on a continuous strip of film, instead of 
 being arranged on a glass disc, and after careful attention 
 Mr. Edison succeeded in doing this in 1893. The 
 modern kinematograph pictures may be said to date 
 from this development of the work of Marey and Muy- 
 bridge. 
 
 In his first fantastic romance, Mr. H. G. Wells created 
 a time-machine by means of which time could be accele- 
 rated or retarded, and a journey could thus be made 
 into the past or the future. The kinematograph is a 
 veritable time-machine, so far as the past is concerned. 
 It can show the life of an insect or the life of a man in 
 a period which is but a fraction of the true duration, and 
 the period of projection may be the same in each case. 
 If the insect be imagined to be endowed with a mind, 
 its life, though but a day, will seem as long as the three 
 
x PRACTICAL PURPOSE 267 
 
 score years and ten of man, for the ultimate conception 
 of time is in terms of duration of life. A thousand 
 years may be but an hour to the time-machine which 
 Mr. Edison has produced to delight and instruct the 
 modern world. 
 
 To the engineer the fascination of experimental 
 research lies, as Cap'n Cuttle would observe, " in the 
 application thereof." He seeks to know ; not from 
 the pleasure to be derived from the acquisition of know- 
 ledge, but in order to bring that knowledge to bear 
 upon everyday problems of life, labour and economy. 
 It must not be supposed that this spirit is necessarily 
 foreign to the man of science. Robert Boyle, one of the 
 most active originators of the Royal Society, refers 
 particularly to practical use of the researches undertaken 
 by himself and other pioneers of the experimental 
 method of investigation in England. Writing in 1646, 
 he alludes to his studies in " natural philosophy, the 
 mechanics and husbandry, according to the principles of 
 our new philosophical college that values no knowledge, 
 but as it hath a tendency to use." 
 
 A Chinese proverb states that he who holds the iron 
 of the world will rule the world. This, however, is only 
 a half truth; for China itself has probably as large 
 deposits of iron ore as any part of the world, but it has 
 not the scientific knowledge required to make the best 
 use of them. The talents which that country possesses 
 have been buried in the ground instead of being used to 
 gain other talents. The masters of the world of iron 
 must be those who understand best the properties of the 
 metal, whether now or in the future. As the result of a 
 systematic study of the effects of adding to iron a special 
 element other than carbon, Sir Robert Hadfield produced 
 his famous manganese-steel, which is used extensively 
 
268 DISCOVERY OH. 
 
 for all purposes where toughness as well as hardness is 
 required, whether for arts of peace or purposes of war. 
 Ten years' persistent research upon the influence which 
 different percentages of manganese exert upon the 
 properties of steel were required before that remarkable 
 metal, manganese-steel, was discovered, and showed 
 the way to the production of dozens of other alloys 
 possessing qualities required in arts and industries. 
 
 It is much easier to accept things as they are than 
 it is to inquire into them and decide whether they 
 are capable of improvement. Throughout the world's 
 history, progress has been accomplished by the men 
 who were not content to do as their forefathers did, 
 but were continually asking, " Why ? ", " Wherefore ? ", 
 " Is that the best way ? ", "Is this the best possible 
 thing ?". Lord Kelvin was a brilliant example of this 
 type of scientific mind, ever critical of defects, alert as 
 to practical needs, and fertile with possible improvements. 
 His views as to the practical value of science were 
 definite and unmistakable. 
 
 The life and soul of science is its practical application ; and 
 just as the great advances in mathematics have been made 
 through the desire of discovering the solution of problems which 
 were of a highly practical kind in mathematical science, so in 
 physical science many of the greatest advances that have been 
 made from the beginning of the world to the present time have 
 been made in the earnest desire to turn the knowledge of the 
 properties of matter to some purpose useful to mankind. Lord 
 Kelvin. 
 
 When Lord Kelvin turned his attention to the mariner's 
 compass, about 1870, that instrument had been in use 
 in much the same form by European navigators for 
 about six hundred years, and by the Chinese long before. 
 The compass in the simple form in which it was used for 
 many centuries was in many respects unsatisfactory. 
 
x PRACTICAL PURPOSE 269 
 
 In the Navy it was found to be useless during gun-fire, 
 and to be affected so much by the rolling of the ships 
 during stormy weather that little dependence could be 
 placed upon it. These defects came directly under the 
 notice of Lord Kelvin after he had undertaken to write 
 an article for a magazine. " When I tried," he said in 
 the article, " to write on the mariner's compass, I found 
 I did not know nearly enough about it. So I had to 
 learn my subject. I have been learning it these five 
 years." He not only noted the defects of the existing 
 instrument, but also set himself to devise a means of 
 remedying them ; and in the end he produced the com- 
 pass which has made his name famous to every nautical 
 man. The existing compasses were made with needles 
 ten, twelve, or even fifteen inches in length, in order that, 
 when shaken, their period of vibration or swing should 
 be long. The card also was made large, with the view 
 of keeping the compass steady ; but the result was that, 
 on account of the weight of the needles and card upon 
 the pivot, the compass was apt to stick, and was always 
 sluggish in its action. 
 
 Lord Kelvin first showed in a mathematical paper 
 that steadiness of the compass at sea in stormy weather 
 could be obtained by small needles and a light compass 
 card instead of large needles and a heavy card, if certain 
 conditions of construction were fulfilled. He took out 
 the first patent for his improvements in 1876, but he 
 had to wait thirteen years before the instrument was 
 adopted as the standard compass for the Navy. The 
 compass is now being supplemented by a new form in 
 which the magnets and card are immersed in a liquid 
 which fills the compass-bowl, and by the gyro-compass, 
 which is independent of magnetic conditions, but it was 
 Lord Kelvin who made the first departure from the crude 
 
270 DISCOVERY CH. 
 
 instruments which had been in daily use by thousands 
 of practical men from early times without one of them 
 suggesting any substantial improvement. 
 
 All sailors are grateful to Lord Kelvin for his inven- 
 tions for the preservation of life at sea, notably by means 
 of his compass and sounding machine. With these two 
 aids to navigation a safe course can be followed with 
 confidence in fog or darkness ; and every sailorman 
 can tell of disasters from which he was saved by them. 
 A characteristic tribute to Kelvin from a sailor's point 
 of view has been given by Admiral Sir W. R. Kennedy. 
 
 " Some years ago," he says, " I left a port on the coast of 
 Patagonia in the Ruby. We shaped a course for Golfo Nuevo 
 for the night. At 8 p.m. the navigating officer came into my 
 cabin and showed me the position of the ship, well clear of the 
 land, and 100 fathoms no bottom, marked on the chart. ' All 
 right,' I said. ' Get a cast of the lead.' * Throw Thomson 
 overboard,' was the way I put it. The navigator looked at me 
 to see if I was joking. ' Why, there's no bottom at 100 fathoms, 
 sir.' 'Well, heave Thomson over.' He left the cabin, and 
 presently I heard the whirr of the wire suddenly stop. I rushed 
 on deck. Fifteen fathoms ! Stop her, hard-a-port, leadsmen 
 in both chains ! Sure enough, 15 fathoms. I hove to all night, 
 head off shore, and next morning steered for the gulf, which we 
 reached without further adventure, but had we continued on 
 our course we should have been ashore before daylight. The 
 navigating officer was not at fault, but the coast-line was not 
 correctly charted. No wonder that we sailors bless the name of 
 Lord Kelvin." 
 
 By his improvements of the two oldest aids to naviga- 
 tion the compass and the sounding line Lord Kelvin 
 earned profound gratitude from all who go to sea. He 
 has been called the best friend the sailor ever had ; 
 and it is said that a blue- jacket was once overheard to 
 remark, " I don't know who this Thomson may be, but 
 every sailor ought to pray for him every night." 
 
x PRACTICAL PURPOSE 271 
 
 Lord Kelvin's work for submarine telegraphy is another 
 example of a practical problem solved by scientific know- 
 ledge. The first Atlantic cable was laid in 1858, but 
 scarcely had the enthusiasm awakened by it begun to 
 subside when the signals grew more and more feeble, 
 and in a few weeks the cable altogether ceased to trans- 
 mit messages. This failure was sufficient to discourage 
 most people, but Lord Kelvin encouraged a fresh 
 attempt. " What has been done," he said, " will be 
 done again. The loss of a position gained is an event 
 unknown in the history of man's struggle with the forces 
 of inanimate Nature." Faith and courage were both 
 required to attack the problem again. A new type 
 of cable was designed, better adapted than previous 
 kinds to bear the strain of laying, and in 1865 this 
 cable had established telegraphic communication be- 
 tween England and America. The appliance, known 
 as the siphon-recorder, invented by Lord Kelvin to 
 register the electric impulses transmitted by the 
 cable, still remains in universal use as the standard 
 instrument in submarine telegraphy. It was scientific 
 knowledge, and the spirit of converting difficulties into 
 opportunities, that made Trans-Atlantic telegraphy 
 possible. 
 
 When the first iron ships were built, it was found that 
 the compasses were so greatly affected by the magnetism 
 of the ships that accurate navigation was impossible. 
 Long before Kelvin devised his instrument, a method 
 of determining a ship's permanent and temporary 
 magnetic conditions had been worked out, and a means 
 of counteracting them had been found. No magnetic 
 compass would be of any practical use if the effect upon 
 it of the fixed and movable iron of a ship could not be 
 compensated effectively. 
 
272 DISCOVERY CH. 
 
 The problem presented by the use of iron in ships 
 was definite but complicated ; and it could be solved 
 only by scientific investigation. Mr. Archibald Smith, 
 a Chancery barrister who devoted all his leisure hours 
 to the application of mathematics to navigation, had 
 this practical purpose in mind ; and his work was recog- 
 nised by the award to him, in 1872, of a gift of 2,000 
 " for the long and valuable services which he had 
 gratuitously rendered to naval science in connection 
 with the magnetism of iron ships, and the deviation of 
 their compasses." The chief credit must, however, be 
 given to Sir George Airy, the Astronomer Royal, who, 
 in 1838, was asked to undertake experiments on a ship 
 the Rainbow for the purpose of discovering a correction 
 for the deviation of the compass produced by the iron 
 of which it was constructed. The deviation was so 
 great that the compass of the ship was as much as fifty 
 degrees out of the magnetic north and south direction. 
 
 Airy investigated the subject theoretically as well as 
 practically, and calculated the strength of the magnetic 
 action required to counteract the disturbance. In a 
 month he had completed his inquiry. He took the 
 necessary compensating magnets and iron correctors 
 to Deptford, where the ship was lying, mounted them 
 in their proper places, tried the ship, and the compass 
 was then found to be sensibly correct. In the same 
 year, another iron ship the Ironsides built at Liver- 
 pool, had her compass similarly corrected by Airy ; 
 and in this case, as in the Rainbow, the disturbance 
 was so great as to make the vessel worthless without a 
 mechanical means of correcting the effect due to the 
 iron. 
 
 The success of the methods employed for the correction 
 soon became widely known, and led immediately to 
 
x PRACTICAL PURPOSE 273 
 
 extensive building of iron ships. Though some acknow- 
 ledgment of an important service thus rendered to 
 navigation might have been expected, the Admiralty 
 refused to sanction any reward for it ; possibly because 
 the Government did not then possess a single iron vessel 
 and was not disposed to urge the inquiry into the effect 
 of a ship's magnetism upon the compasses. When Airy 
 commenced the investigation, the whole subject was in 
 darkness, yet by the application of a mechanical theory 
 he brought it under control. Lord Kelvin made a great 
 advance later by the use of short needles for the compass 
 cards, but the method of correcting the compasses in 
 iron ships, now adopted not only in the merchant 
 service but also in the navies of all countries, is that 
 worked out by Sir George Airy in 1839. Airy mathe- 
 matician and astronomer has thus been justly called 
 the father of the mode of mechanical compensation of 
 the compass now followed throughout the civilised 
 world. 
 
 Neither Airy nor Kelvin had any special knowledge 
 of ships' compasses when they took up the problems 
 which they solved with such complete success, but they 
 knew that the best way to attain a practical purpose 
 is to submit the conditions to scientific analysis before 
 devising arrangements to meet them. This method 
 may be tedious, but it is always the best in the end. No 
 matter to what branch of human activity the subject 
 belongs, the preliminary scientific investigation under- 
 taken with the view of understanding it fully makes 
 the surest foundation of advance. All work which 
 has not this basis is of the empirical, trial and error, rule 
 of thumb, kind ; it is a shot in the dark, and though the 
 target may be hit the chances are very much against it. 
 When science is brought to bear upon a practical problem, 
 
 G.D. S 
 
274 DISCOVERY CH. 
 
 it first discovers exactly what has to be done, and then 
 seeks the most efficient way of doing it. 
 
 In 1865, Pasteur was urged by Dumas to undertake 
 the investigation of a disease of silkworms, called 
 pebrine, which had for several years been ruinously 
 prevalent in the south of France. The loss was estimated 
 at four millions sterling ; and the disease had spread to 
 many other countries from which silkworms' eggs had 
 been brought to France. Pasteur had no intimate 
 knowledge of silkworms, and he hesitated to take up the 
 study of the causes of the epidemic. Writing to Dumas 
 he said : 
 
 Your proposition throws me into a great perplexity ; it is 
 indeed most flattering, and the object is a high one ; but it 
 troubles and embarrasses me ! Remember, if you please, that 
 I have never even touched a silkworm. If I had some of your 
 knowledge on the subject I should not hesitate ; it may even 
 come within the range of my present studies. However, the 
 recollection of your many kindnesses to me would leave me 
 bitter regrets if I were to decline your pressing invitation. Do 
 as you like with me. Pasteur. 
 
 Many silkworm cultivators expressed regret that the 
 Government should choose a " mere chemist " for 
 the investigation of the disease instead of a zoologist 
 or silkworm cultivator. Pasteur only said, " Have 
 patience " ; and he began his attack of the problem 
 with the precision and acuteness of observation 
 characteristic of him. He suspected that certain 
 " corpuscles " found in the bodies of diseased silkworms 
 and in the moths and their eggs were disease-producing 
 organisms, and directed his chief studies to them, while 
 making also a careful investigation of the whole disease. 
 He proved that the disease was not only contagious, 
 but hereditary diseased moths laying diseased eggs 
 
x PRACTICAL PURPOSE 275 
 
 from which came diseased silkworms which died young or 
 were useless for the production of silk. Thus the disease 
 passed on by inheritance from year to year. The germs 
 in eggs laid by diseased moths survived ; but those 
 left on leaves, or in the dust, or in the bodies of dead 
 moths, soon perished. Only in the diseased and living 
 eggs was the contagion maintained. 
 
 These things were proved by repeated experiments, and by 
 observations by Pasteur in his own breeding- chamber ; and they 
 made him believe that the disease might be put an end to by the 
 destruction of all diseased eggs. To this end he invented the 
 plan which has been universally adopted, and has restored a 
 source of wealth to the silk districts. 1 Each female moth, when 
 ready to lay eggs, is placed on a separate piece of linen on which 
 it may lay them all. After it has laid them, and has died, it is 
 dried and then pounded in water, and the water is examined 
 microscopically. If " corpuscles " are found in it, the whole of 
 the eggs of this moth, and the linen on which they were laid, 
 are burnt ; if no " corpuscles " are found, the eggs are kept, to 
 be, in due time, hatched, and they yield healthy silkworms. 
 Sir James Paget. 
 
 By the adoption of these methods, arrived at by 
 scientific investigation, a national industry was restored, 
 and the bread of hundreds of poor families was again 
 assured. No wonder that his name is now blessed in 
 the land which profits by the fruit of his splendid 
 discoveries ; yet throughout the whole period of his 
 researches he met with unbelief from practical culti- 
 vators of silkworms, and opposition from merchants of 
 eggs and chimerical remedies for the disease. 
 
 The successful production of Smyrna figs in Cali- 
 fornia is a remarkable' example of the application of 
 scientific knowledge of fertilisation of plants to the 
 establishment of a new industry. The green fig which 
 grows in our gardens usually has no true seeds, and does 
 
276 DISCOVERY OH. 
 
 not retain the flavour when dried. In the latter part 
 of the nineteenth century, an endeavour was made to 
 produce seed-bearing figs in California. A number of 
 cuttings of Smyrna fig-trees was obtained and planted, 
 but with no success. The failure was due to the fact 
 that the dried Smyrna fig owes its peculiar flavour to 
 the number of ripe seeds which it contains ; and these 
 seeds are only formed when the flowers of the cultivated 
 fig are fertilised with pollen derived from the wild fig, 
 or caprifig. 
 
 Since time immemorial it has been the custom of 
 natives in Oriental regions to break off the fruits of the 
 wild fig, bring the branches to the edible fig-trees, and 
 tie them to the limbs. From the wild fig thus brought 
 to the plantations, or from a caprifig which may be 
 planted with the other trees, a species of minute wasp 
 emerges at the right season covered with pollen ; it 
 crawls into the flower-receptacles of the edible fig, 
 fertilises them, and thus produces a crop of seeds, as 
 well as assists in the ripening of the fruit. 
 
 Herodotus knew that an insect passed from the wild 
 fig to the cultivated tree, and Pliny the Elder, in the 
 beginning of our era, described the relation of the insect 
 to the two kinds of fig tree, but he knew nothing of the 
 process of fertilisation, and supposed that the seeds of 
 the wild fig were themselves transformed into insects. 
 For a couple of thousand years the fig tree was cultivated 
 in the Mediterranean regions without anyone troubling 
 to examine the details of the natural processes upon 
 which the production of the seeds depended. This 
 knowledge, combined with persistent endeavour extend- 
 ing over nineteen years, has enabled the United States 
 to transplant to the new world a distinctive product of 
 the old, and to base a new industry upon it. 
 
x PRACTICAL PURPOSE 277 
 
 When the practical man particularly he who is 
 engaged in rural pursuits reaps any profit from science, 
 he does so against his own convictions. The motto of 
 the Royal Agricultural Society of England is " Practice 
 with Science," yet how rarely do farmers show by word 
 or deed that they realise the intimate connection between 
 scientific investigations and agricultural arts. To the 
 husbandman in general, science means theory, and his 
 own experience fact ; and he is as contemptuous of the 
 one as he is confident of the other. He will pay a fancy 
 price for a patent fertiliser, when a little scientific 
 knowledge would show him that the same stimulating 
 constituents could be obtained at one-third the cost, or 
 less. He will lose hundreds of pounds on his crops or 
 stock, by pests and diseases, without knowing anything 
 of the nature of his enemies, against which he has to 
 fight. He prides himself upon being a " practical man," 
 and regards all scientific work as unpractical, though 
 every fly that troubles him, and every fungus that 
 infests his plants, has to be studied laboriously by 
 biologists before any accurate knowledge of its life- 
 history can be obtained. Whatever is known of the 
 exact relation between cause and effect in all branches 
 of agriculture, and whenever fact can be placed against 
 opinion as regards diseases of animals and plants, the 
 credit belongs to the scientific investigator, and not to 
 the actual cultivator of the soil. 
 
 Swift, with severe satire, made the King of Brob- 
 dingnag express to Gulliver the opinion " That whoever 
 could make two ears of corn, or two blades of grass, to 
 grow upon a spot of ground where only one grew before, 
 would deserve better of mankind, and do more essential 
 service to his country, than the whole race of politicians 
 put together." The increase has been effected, but the 
 
278 DISCOVERY OH. 
 
 men whose scientific work has led to it are mostly 
 unknown to the politicians and other people who benefit 
 by it. 
 
 Before the knowledge of chemistry had sufficiently 
 advanced to provide a basis for a theory of nutrition of 
 the plant, all observation of the good effect of this 
 or that substance on the crop was merely empiric and 
 possessed no value beyond the particular case to which 
 it referred. The science of agricultural chemistry may 
 be said to have been founded early in the nineteenth 
 century when Davy was appointed professor of chemical 
 agriculture to the Board of Agriculture. In the latter 
 part of the previous century, Priestley had shown that 
 green plants, when exposed to bright sunlight, decom- 
 pose the carbonic acid in the atmosphere into its elements 
 carbon and oxygen, keeping the carbon for themselves 
 and setting free the oxygen ; but this fact, and De 
 Saussure's work on plant chemistry, may be said to 
 represent the state of scientific knowledge of the subject 
 at the time. 
 
 Davy did not make any very substantial contributions 
 to the science of agriculture, but he rendered valuable 
 service by insisting upon the value of studying agriculture 
 problems by scientific methods. He knew that the 
 farm and not the laboratory provided the final test of 
 the principles he expounded ; and he carried out some 
 field experiments himself. " Nothing is more wanting 
 in agriculture," he wrote, " than experiments in which 
 all the circumstances are minutely and scientifically 
 detailed. This art will advance with rapidity in pro- 
 portion as it becomes exact in its method." 
 
 Twenty-five years after Davy's lectures, the great 
 French agricultural chemist, Boussingault, published 
 the results of detailed investigations of what may be 
 
X PRACTICAL PURPOSE 
 
 termed the balance-sheet of plant growth; and his 
 conclusions were adopted by the renowned German 
 chemist, Liebig, about 1840. Liebig took up the 
 complicated problems of soil constitution and fertility 
 with the practical purpose in mind of increasing its 
 productiveness. He traced clearly the relations between 
 the nutrition of plants and the composition of the 
 soil ; and he was the first to study carefully the mineral 
 constituents of plants, and to recognise the import- 
 ance of certain substances, especially potash and 
 phosphates. 
 
 The principle of replacing artificially the substances 
 removed from the soil by crops was given a scientific 
 foundation by Liebig's work, and is now followed by 
 every progressive farmer. Knowing the nature of a 
 soil and the needs of a plant, suitable artificial fertilisers 
 can be applied to make up any deficiency in the main 
 constituents required for vigorous and profitable growth. 
 For example, a soil may be rich in humus, and in com- 
 pounds of nitrogen and phosphorus, and yet be almost 
 barren land because of deficiency in another essential 
 constituent potassium. Dr. Cyril Hopkins tells an 
 impressive story of the result of applying potassic 
 fertilisers to such land in Illinois. A man who had been 
 farming soil of this kind came to see a demonstration 
 field of the Illinois Agricultural Experiment Station, 
 and brought with him his wife and children. 
 
 As he stood looking first on the corn on the treated and 
 untreated land, and then at his wife and children, he broke down 
 and cried like a child. Later he explained to the superintendent 
 who was showing him the experiments that he had put the best 
 of his life into that kind of land. " The land looked rich," he 
 said, " as rich as any land I ever saw. I bought it and drained 
 it and built my house on a sandy knoll. The first crops were 
 fairly good, and we hoped for better crops, but instead they grew 
 
280 DISCOVERY OH. 
 
 worse and worse. We raised what we could on a small patch 
 of sandy land, and kept trying to find out what we could grow 
 on this black bogus land. Sometimes I helped the neighbours 
 and got a little money, but my wife and I and my older children 
 have wasted twenty years on this land. Poverty, poverty, 
 always ! How was I to know that this single substance which 
 you call potassium was all we needed to make this land pro- 
 ductive and valuable ? " 
 
 Without the artificial supply of nitrogen to the soil, it 
 would be practically impossible to grow sufficient wheat 
 to supply the needs of the present inhabitants of the 
 earth who use it for food. The nitrogen is obtained 
 chiefly from nitrate of soda mined in Chile, but these 
 deposits are by no means inexhaustible. Fortunately, 
 science has come to the rescue ; and nitrogenous ferti- 
 lisers are now produced on a large scale from the nitrogen 
 of the atmosphere. The chief source of potash, which 
 greatly increases the fertility of certain soils, is immense 
 saline deposits in the Stassfurt district of Germany. 
 The deposits were discovered about the middle of the 
 nineteenth century, and were at first regarded as useless, 
 but now nearly all the potash required in the arts as 
 well as in agriculture is obtained from them. 
 
 In addition to nitrogen and potash, most plants require 
 phosphorous compounds or phosphates to stimulate 
 their development and quicken their ripening. It was 
 an English country gentleman, Sir John Bennet Lawes, 
 who, in 1 834, guided by the researches of De Saussure 
 on vegetation, showed by experiments the value of this 
 constituent when added to the soil, and discovered a 
 means of producing any quantity of it. Mineral phos- 
 phates, such as apatite, are usually too insoluble to have 
 any practical value in agriculture, but Lawes found that 
 if they were previously treated with sulphuric acid (oil 
 of vitriol), a " superphosphate " was produced in which 
 
PRACTICAL PURPOSE 281 
 
 the phosphates are almost entirely soluble in water, 
 and which has a most beneficial influence upon growth 
 upon heavy soils, as well as upon light. This production 
 of this fertiliser was the result of deliberate intention 
 and practical purpose, and it has proved of the highest 
 importance in agriculture. 
 
 About six million tons of superphosphate are now 
 manufactured annually, and the influence of this com- 
 pound on the productiveness of the soil in civilised 
 countries is incalculable. The farmer is no longer 
 dependent, as he was formerly, upon bone or guano for 
 a supply of phosphates, for the vast deposits of phos- 
 phatic rocks and minerals can be converted into a powder 
 which enables him to restore or increase the fertility of 
 his land in the most effective and economical manner. A 
 dressing so small as half a hundredweight cast over an 
 acre has been found to double the yield of cereals in soil 
 of Southern Australia ; and the effect has been found 
 equally marvellous in other places. 
 
 Lawes was thus the actual benefactor of mankind to 
 whom Swift gave so high a place in Gulliver's Travels. 
 For more than fifty years he carried on agricultural 
 experiments at Rothamsted, in Harpenden, Hertford- 
 shire, with Sir J. H. Gilbert, who had been a pupil of 
 Liebig's ; and the work of these two men has made the 
 Rothamsted Experiment Station renowned throughout 
 the world. A memorial tablet in Harpenden Parish 
 Church bears the appropriate inscription : "In affec- 
 tionate memory of Sir John Bennet Lawes, Bart., 
 F.R.S., born at Rothamsted, Dec. 28, 1814, died at 
 Rothamsted, Aug. 31, 1900. He used his long life 
 and his great knowledge and experience as an agri- 
 cultural chemist and as a practical and scientific 
 farmer, in the pursuit of truth, and for the benefit of 
 
282 DISCOVERY ca. 
 
 his fellow men in his own country and in all parts of 
 the world." 
 
 Agricultural Experiment Stations similar to that at 
 Rothamsted now exist in all civilised countries ; they 
 are laboratories of industrial or technical research in 
 which problems are attacked with the object of ensuring 
 the supply of man's daily bread by fighting the natural 
 agents and forces which would deprive him of it. 
 Thousands of chemists are engaged in researches which 
 have as their aims the definite practical purposes of 
 increasing man's comforts or pleasures, or strengthening 
 his power over Nature. They have by their intensive 
 investigations produced hundreds of dyes from coal-tar ; 
 they have produced an artificial indigo which has taken 
 the place of the natural dyestuff even in the home of the 
 indigo plant, Asia, and a dyestuff, alizarin, which has 
 similarly displaced the natural dye obtained from the 
 madder root. Numerous other natural products have 
 been built up from their elements by chemical techno- 
 logists, mostly by systematic purposeful research having 
 profitable commercial ends in view. We have as the 
 result, cabinets of synthetic drugs to alleviate pain and 
 fight disease, and artificial essences which cannot be 
 distinguished in their fragrant qualities from the scents 
 of flowers lilac, lily of the valley, violet and the rose. 
 
 The intention of technical research is not so much to 
 contribute to scientific knowledge as to create new 
 industries or develop old into higher or more productive 
 forms. The country which neglects this pioneer branch 
 of its industrial army cannot maintain an important 
 position in the struggle for existence or supremacy in 
 commercial life. Lord Beaconsfield once said that the 
 condition of the chemical trade of a country is a baro- 
 meter of its prosperity, and King George the Fifth 
 
x PRACTICAL PURPOSE 283 
 
 accentuated this remark in a speech made at the opening 
 of a Congress of Applied Chemistry in London in 1909. 
 His Majesty said : 
 
 I fully appreciate the important part which chemistry plays 
 in almost every branch of our modern industry. We all recognise 
 that without a scientific foundation no permanent superstructure 
 can be raised. Does not experience warn us that the rule of 
 thumb is dead, and that the rule of science has taken its place, 
 that to-day we cannot be satisfied with the crude methods 
 which were sufficient for our forefathers, and that those great 
 industries which do not keep abreast of the advance of science 
 must surely and rapidly decline ? 
 
 It would be easy to give many examples of the bene- 
 ficial effects of the co-operation of scientific theory with 
 practical methods. One of the most striking illustrations 
 is afforded by the optical trade. About 1863, the firm 
 of Carl Zeiss, of Jena, asked Ernst Abbe to assist them 
 in the development of the microscope by investigating 
 the optical theory of the instrument. Abbe proved 
 mathematically that with the glass then at the optician's 
 disposal no great improvement in the optical parts of 
 the microscope could be expected. Progress in the art 
 of glass-making was necessary before any substantial 
 advance could be made in microscopic or photographic 
 lenses. Abbe himself, with Otto Schott, began, there- 
 fore, in 1881, to investigate the relation between the 
 optical properties and the chemical composition of 
 glasses. When they began their work, about six 
 chemical elements were the constituents of glasses ; 
 and they tested by experiment the effect of adding 
 definite quantities of other substances, as had been done 
 previously in a small way by the Canon W. V. Harcourt 
 in England. 
 
 What had been a rule-of-thumb industry was thus 
 re-constructed on a scientific basis. Glasses could be 
 
284 DISCOVERY OH. 
 
 produced having particular properties for microscope 
 lenses, for photographic lenses, for thermometers, or 
 any other special purpose. Works were established at 
 Jena, and they soon became the chief centre of optical 
 glass manufacture in the world. On account of the 
 indifference shown to scientific theory by its manu- 
 facturers and State officials, England lost an industry in 
 which it was once pre-eminent. 
 
 This has not only been the case with glass manufacture, 
 but also is largely true of the construction of photo- 
 graphic lenses. The principles of the design of such 
 lenses were worked out by Sir John Herschel, Sir 
 William Hamilton and Sir George Airy, but their 
 significance was not appreciated by practical opticians 
 in the country of their origin, and it was left to optical 
 experts of another nation to apply them to practical 
 needs. Empirical methods followed by British opticians 
 have achieved some notable successes in optical instru- 
 ments, but the guidance of theory is essential for steady 
 advance, and scientific knowledge is necessary to see any 
 close relation between theory and practice. In origin- 
 ality and inventiveness, the English mind will compare 
 favourably with that of any race, but its attitude to 
 scientific theory is supercilious, and the nation suffers 
 loss by it. If England does not lead in industrial 
 development, it is not because of lack of new ideas, but 
 on account of want of scientific insight among her 
 manufacturers, and want of faith in the ultimate value 
 of organised industrial research. We commend to the 
 men who have the nation's future in their keeping the 
 words of a president of the Royal Society : 
 
 Sciencia vinces whether it be on the field of battle, on the 
 waves of the ocean, amid the din and smoke of the workshop, 
 or on the broad acres under the light of heaven ; and assuredly, 
 
x PRACTICAL PURPOSE 285 
 
 in the future, even more than in the past, not only the prosperity, 
 but even the existence of the Empire will be found to depend 
 upon the " improvement of Natural Knowledge " that is, upon 
 the more complete application of scientific knowledge and 
 methods to every department of industrial and national activity. 
 Sir William Huggins. 
 
 It is commonly supposed that the marvellous develop- 
 ment of aviation within recent years owes nothing to 
 scientific work ; indeed, the assertion is often made 
 unjustly so that men of science declared the flight 
 of an aeroplane to be a mathematical impossibility. 
 Aviation engineers have certainly had few scientific 
 principles to guide them in the design of their machines, 
 and the improvements which have been effected have 
 been by trial-and-error methods ; but the error has 
 unfortunately involved the sacrifice of many promising 
 lives. Artificial flight has been achieved chiefly by these 
 empirical methods ; and in the absence of exact know- 
 ledge they are the only methods available, though they 
 are expensive and wasteful. 
 
 As in other cases mentioned already, the problem of 
 flight with heavier-than-air machines was approached 
 by two separate roads of invention and science. Early 
 in the nineteenth century, Sir George Cayley designed 
 an aeroplane driven by an engine which used the 
 explosive force of gunpowder ; and the machine appears 
 to have lifted itself from the earth. Nearly forty years 
 later, W. S. Henson projected, and his friend J. String- 
 fellow constructed, model aeroplanes from Cayley's 
 designs, driven by a light steam-engine of about one- 
 third horse-power ; and the models are said to have been 
 capable of free flight. About 1875 Alphonse Penaud, 
 a French mechanic, constructed the well-known toy 
 aeroplane with a propeller in the rear and driven by a 
 
286 DISCOVERY OH. 
 
 rubber band, the machine thus utilising motive energy 
 which it carried with it. 
 
 Experiments with man-carrying machines were made 
 about 1889 by Otto Lilienthal in Germany, Percy 
 Pilcher in Scotland, and Octave Chanute in the United 
 States. These machines were, however, only gliders, 
 by means of which the experimenters could soar in the 
 air for a hundred yards or so, after taking a short run 
 against the wind, along the top of a hill or mound. In 
 none of these cases was a motor used successfully to 
 drive the wings of the aeroplane against the air and thus 
 maintain it from falling. Sir Hiram Maxim built in 1894 
 a huge machine driven by a steam engine, and proved 
 by it that the whole weight could be lifted slightly 
 off the rails on which the machine ran by driving the 
 planes against the air with sufficient velocity. A little 
 later M. Ader, in France, traversed a distance of about 
 fifty yards in his " Avion " aeroplane. 
 
 All these machines may be not inappropriately 
 classified as devices of engineers to achieve flight by 
 invention call it practical experiment if you will- 
 before the principles of dynamic motion had been studied. 
 The practical man makes his machine first and lets 
 experience decide whether its design is sound or not ; 
 the scientific man begins by investigating the principles 
 involved in the problem, and then suggests how they 
 may be met. The only satisfactory way to determine 
 such principles is by experiment and calculations based 
 upon the results. The possibilities of artificial flight 
 were studied experimentally by a man of science at a 
 time when anyone who gave attention to the subject 
 received nothing but derision for his pains. Modern 
 aviation was based upon the results he obtained, for 
 he himself first showed that a system of planes could 
 
x PRACTICAL PURPOSE 287 
 
 be sustained in the air if made to advance through it 
 fast enough. 
 
 Until a few years ago, very little was known of the 
 resistance offered to air by a body advancing through it. 
 Sir Isaac Newton considered the subject, and came to 
 the conclusion that the resistance opposed to a thing 
 in rapid motion would be so great that enormous 
 mechanical power would be required if artificial flight 
 were to be accomplished. It was not a practical 
 engineer or an aviator who undertook experiments to 
 test the rule which Newton gave to calculate this power, 
 but an American man of science Samuel Pierpont 
 Langley, secretary of the Smithsonian Institution of 
 Washington. 
 
 Prof. Langley commenced his experiments in 1887 ; 
 and his work gave, for the first time, some accurate 
 knowledge as to the resistance offered to planes moving 
 through air at different speeds and inclinations. He 
 proved that what had been called the Newtonian Law 
 was wrong ; and that it takes less power to support a 
 plane moving through air at high speed than at low. 
 By simply moving a given weight fast enough in a hori- 
 zontal plane, Langley found that it was possible to 
 sustain the weight with less than one-twentieth the power 
 demanded by Newton's rule. His conclusion as to the 
 relation of speed to power for a body in motion in air 
 was as follows : 
 
 These new experiments (and theory also when viewed in their 
 light) show that if in such aerial motion there be given a plane 
 of fixed size and weight inclined at such an angle and moved 
 forward at such a speed that it shall be sustained in horizontal 
 flight, then the more rapid the motion is, the less will be the 
 power required to support and advance it. Prof. S. P. Langley. 
 
 This rule, now known as Langley's Law, represented 
 
288 DISCOVERY OH. 
 
 a definite advance of knowledge secured by the methods 
 of exact science. The practical men who, in these 
 days of rapid locomotion, might have been expected to 
 investigate the laws of air resistance, left it to a man of 
 science to prove that a rule which had been accepted 
 for two hundred years was incorrect. His experiments 
 demonstrated that relatively little power was required 
 to sustain a given weight if the horizontal velocity 
 reached a certain rate. All that was needed in order to 
 make mechanical flight possible was a light motor 
 capable of forcing a plane or set of planes through the 
 air with sufficient velocity. 
 
 Guided by his results, Langley had a model aeroplane 
 constructed, weighing about 25 Ib. ; and successful 
 flights, each about half a mile in length, were made 
 with it in 1896. His experiments were regarded, how- 
 ever, as the trivial amusements of a scientific man ; 
 and when, in 1903, his man-carrying aeroplane was 
 wrecked, owing to an accident in launching it, so much 
 ridicule was thrown upon the trials that he abandoned 
 the subject and devoted himself to other things. Eleven 
 years later, in 1914, the same machine was used for 
 flights with a pilot. Langley did not live to see this 
 success, but he never lost faith or confidence in the 
 ultimate possibility of aerial flight with heavier-than-air 
 machines. Concluding an account of his experiments in 
 1897, he said : 
 
 I have brought to a close the portion of the work which seemed 
 to be specially mine the demonstration of the practicability of 
 mechanical flight and for the next stage, which is the com- 
 mercial and practical development of the idea, it is probable 
 that the world may look to others. The world, indeed, will be 
 supine if it does not realise that a new possibility has come to it, 
 and that the great universal highway overhead is now soon to 
 be opened. Prof. S. P. Langley. 
 
x PRACTICAL PURPOSE 289 
 
 How completely Langley's belief in flight by aero- 
 planes has been justified is known now to everyone, 
 though his experiments are rarely mentioned. Fara- 
 day once said, referring to the electric dynamo, " I gave 
 you this machine as an infant ; you bring it back as a 
 giant." Had Langley lived, the same remark could 
 have been applied appropriately by him to the develop- 
 ment of flying machines from his models. Purely 
 scientific investigations gave the world the dynamo, 
 and with the construction of this means of producing 
 electricity there commenced a new era in engineering. 
 In like manner, the work of a man of science opened a 
 new epoch in the history of aerial navigation. 
 
 When, in May, 1896, Langley's power-driven model 
 aeroplane flew over the Potomac River for a minute 
 and a half (for which time only it was provided with 
 fuel and water), and accomplished a flight of little over 
 half a mile before it settled down upon the water with 
 a gentle descent, the possibility of free dynamic flight 
 was established. It was Langley, and no one else, who 
 was the father of modern aeroplaning, both on account 
 of his investigations of the scientific principles of air 
 resistance and the work of the wind, and because he put 
 the principles into practice by constructing a self- 
 balancing heavier-than-air machine which would sustain 
 itself in the air so long as the power driving it lasted. 
 No one before Langley had succeeded in building an 
 aeroplane capable of sustained free flight with a man as 
 pilot. 
 
 When Wilbur and Orville Wright commenced their 
 experiments in artificial flight, the only exact experiments 
 they could find as to the resistance of the air to machines 
 driven at different velocities were those made by the 
 man of science, S. P. Langley. They were the pioneers 
 
 G.D. T 
 
290 DISCOVERY OH. 
 
 of sustained flight with man-carrying aeroplanes, and 
 they have acknowledged that their confidence in the 
 practical solution of the problem was derived from 
 Langley and his work. 
 
 The knowledge that the head of the most prominent scientific 
 institution of America believed in the possibility of human flight 
 was one of the influences that led us to undertake the preliminary 
 investigations that preceded our active work. He recommended 
 to us the books which enabled us to form sane ideas at the outset. 
 It was a helping hand at a critical time, and we shall always be 
 grateful. Wilbur and Orville Wright. 
 
 In December, 1903, the Brothers Wright made the 
 first actual flight with an aeroplane driven by a petrol 
 motor. It is constantly stated that artificial flight 
 would have been accomplished long before if engines 
 light enough to drive them had been available, but that 
 is not the case. Flights with two, three, or more 
 passengers show that lightness of the motor is not the 
 only consideration, and motors with equivalent weights 
 were available ten years before the Wrights designed 
 their man-carrying aeroplanes. It was by following 
 the scientific guidance of Langley, and using mechanical 
 ingenuity to extend it, that they were able to give prac- 
 tical effect to the desire of man to rise above the clouds. 
 
 Though the Wrights were the first aviators to make 
 successful flights with a heavier-than-air machine driven 
 by its own power, little was known of their work for 
 about two years after 1903. During this period they 
 were engaged in perfecting their aeroplane until, in 1905, 
 they were able to remain in the air for half an hour and 
 cover a distance of about twenty-four miles. They did 
 not give a public demonstration of their achievements 
 until 1908 two years after a young Brazilian, M. Santos 
 Dumont, had made a short public flight in France, using 
 
x PRACTICAL PURPOSE 291 
 
 an aeroplane designed by him without any definite 
 knowledge of what the Wrights had done. Since that 
 period, the advance of dynamic flight has been rapid 
 and marvellous ; and aeroplanes of various types are 
 now in everyday use, particularly for military purposes. 
 
 The performances of the earlier machines depended 
 very largely upon the pilots, who had to give close 
 attention to different controls in order to keep the planes 
 in a condition of stability in the air. The problem of 
 producing a machine which is automatically steady in 
 free flight is largely mathematical ; and it involves the 
 theory of small oscillations about a state of steady 
 motion developed by Lagrange, Kelvin, Routh and 
 other men of science. Definite attention has been given 
 to the mathematical conditions which have to be satisfied, 
 in order to solve the problem of inherent stability, by 
 G. H. Bryan and F. W. Lanchester ; and their con- 
 clusions, with the results of experimental research on 
 models at the National Physical Laboratory, largely by 
 L. Bairstow, have led to the construction of the B.E. 
 biplane, which is almost independent of the pilot except 
 when near the ground, where personal control must 
 be exercised. 
 
 The forms of early aeroplanes were determined chiefly 
 by trial-and- error methods ; and little inducement was 
 given to scientific men to devote themselves to the 
 experimental and theoretical studies by which the most 
 efficient types of machine can be secured. Work in 
 the laboratory and calculation in the study must, how- 
 ever, eventually determine the lines upon which a 
 flying machine can be designed that may be launched 
 into the air with as much confidence in its safety and 
 inherent stability as a vessel can be trusted to leave 
 the slips of the dockyard in which it has been built. 
 
CHAPTER XI 
 
 ACROSS THE BORDER 
 
 Nature does not allow us to explore her sanctuaries all at 
 once. We think we are initiated, but we are still only 
 on the threshold. Seneca. 
 
 The seemingly useless or trivial observation made by one 
 worker leads on to a useful observation by another : 
 and so science advances, " creeping on from point to 
 point." Prof. Silvanus P. Thompson. 
 
 One day telleth another : and one night certifieth another. 
 There is neither speech nor language but their voices are 
 heard among them. Their sound is gone out into all 
 lands : and their words into the ends of the world. 
 Psalm xrx. 2, 3, 4. 
 
 We find ourselves, in consequence of the progress of physical 
 science, at the pinnacle of one ascent of civilisation, 
 taking the first step upwards out on to the lowest plane 
 of the next. Above us still rises indefinitely the ascent 
 of physical poiver far beyond the dreams of mortals 
 in any previous system of philosophy. Prof. Fred- 
 erick Soddy. 
 
 SCIENCE advances by bringing into view facts and 
 phenomena previously unknown. Galileo turns his 
 simple telescope towards the heavens, and lo ! thousands 
 of stars beyond the grasp of unaided vision are revealed ; 
 the microscope is invented, and by its aid an unseen 
 universe, the inhabitants of which are far more numerous 
 than the stars in heaven, is made known. In neither 
 
CH. xi ACROSS THE BORDER 293 
 
 case were new worlds or organisms created, the extension 
 of knowledge being but a consequence of the improved 
 powers of seeing. The limits of visible light-waves 
 have now been extended so that in wireless telegraphy 
 we produce and detect electric waves which do not 
 affect the organ of vision ; and from darkness we 
 derive by X-ray tubes and radium new radiations which 
 light up a land of promise across the border. 
 
 Of all the achievements of science, that which creates 
 the deepest impression upon the minds of most people 
 is wireless telegraphy, the triumphs of which can be 
 traced back to researches carried on in laboratory and 
 study. Its development is due even more to theory 
 than to practical work. When the effects of currents 
 upon magnets, and upon one another, had been deter- 
 mined, science demanded an explanation of them. 
 The effects can be produced in a vacuum, or through 
 glass, wood, or similar substances ; so evidently what 
 seems to be empty space or material bodies must really 
 be filled with something capable of transmitting the 
 electric and magnetic forces. Ampere suggested that 
 the observed facts could be explained by the presence 
 of a universal medium which could convey these forces 
 from one point to another. Henry and Faraday also 
 held this view, and it was developed in detail by a mathe- 
 matical physicist, James Clerk Maxwell, about the 
 middle of the nineteenth century. 
 
 What Maxwell did was to extend by brilliant mathe- 
 matical analysis the conception formed by Faraday as 
 to the propagation of electro-magnetic action by an 
 intervening medium. The theory of " action at a 
 distance " assumed that no medium was actively 
 concerned with the transmission of electric or magnetic 
 forces, whereas Faraday, by experimental researches 
 
294 DISCOVERY OH. 
 
 and reasoning, showed that the action took place along 
 curved lines, which he termed " lines of force." 
 
 Faraday in his mind's eye, saw lines of force traversing all 
 space, whereas the mathematicians saw centres of force attracting 
 at a distance ; Faraday saw a medium where they saw nothing 
 but distance ; Faraday sought the seat of the phenomena in 
 real actions going on in the medium ; they were satisfied that they 
 had found it in a power of action at a distance impressed on the 
 electric fluids. Clerk Maxwell. 
 
 As the result of his analysis of Faraday's experi- 
 mental results, and the lines of force which he invoked 
 to explain them, Maxwell was able to prove that electro- 
 magnetic disturbances, and waves of light, are trans- 
 mitted by one and the same medium, and with the same 
 velocity. Thus, electro-magnetic and optical pheno- 
 mena are identical in kind, and differ only in the rapidity 
 of vibration of the medium- the universal ether which 
 transmits them. Sunlight comes to us across ninety- 
 three millions of miles of so-called empty space, and 
 starlight from distances hundreds of thousands of times 
 greater ; and they both reach us as waves which can 
 be measured, and their interference effects observed, 
 more easily than can those seen on the disturbed surface 
 of a lake or other sheet of water. A medium had to be 
 invented to account for the transmission of these waves ; 
 and this medium is appropriately termed the " ether," 
 signifying the sky the home of the gods. No one can 
 see the ether, or weigh it, or isolate any part of it, yet 
 it apparently pervades all space and permeates all 
 material things, as water does a wet sponge ; and through 
 it electro-magnetic waves, as well as waves of light and 
 heat, are propagated. 
 
 In 1842, Joseph Henry arrived at the conclusion that 
 when an electric spark is produced by the sudden 
 
xi ACROSS THE BORDER 295 
 
 discharge of a Ley den jar or other form of electric con- 
 denser, the spark is not due to a single splash of electricity 
 from one point to another, but to many rapid oscillations 
 of electric action between the two points. The total 
 duration of the discharge is far too short to be analysed 
 by the eye, but if it could be extended over a sufficiently 
 long interval the spark would be seen swinging like a 
 pendulum from one point to the other until the surging 
 disturbance which produced it had settled down again. 
 Both Lord Kelvin and von Helmholtz independently 
 reached the conclusion expressed by Henry before them 
 as to the oscillatory character of the electric discharge ; 
 and Clerk Maxwell showed that such a discharge must 
 give rise to etheric disturbances which would travel 
 through space with the velocity of light. 
 
 When a theory can be stated in mathematical terms 
 it is possible to predict effects before they are actually 
 observed. The consequences of Maxwell's theory were 
 clearly understood by physicists, two of whom, Prof. 
 Heinrich Rudolf Hertz in Germany, and Sir Oliver 
 Lodge in England, devoted themselves to the task of 
 detecting the ether waves which must be created by an 
 oscillatory electric discharge. About 1888 Maxwell's 
 prophetic conclusions were brought within the range of 
 demonstration by Hertz, who discovered a means of 
 increasing the amplitude of the electric waves radiated 
 from the discharge circuit, and devised a sensitive 
 detector of these periodic disturbances of the ether. 
 It was Hertz, therefore, who provided the experimental 
 proof for which science had waited twenty years. 
 
 The difference between light waves and electric waves 
 now called Hertzian waves in honour of their discoverer 
 is a difference in length, or of rate of vibration of the 
 ether. The shortest waves which affect our sight are 
 
296 DISCOVERY CH. 
 
 those of violet light, produced by about seven hundred 
 millions of millions of vibrations in the ether per second. 
 This frequency of oscillation decreases as we pass down 
 the scale of colour through blue, green, yellow and orange 
 to red light, which is caused by about four hundred 
 millions of millions of etheric vibrations in a second. 
 Hertzian waves are due 'to much slower vibrations in 
 the ether a few millions per second and though they 
 do not affect our visual sense directly, they have precisely 
 the same other properties as waves of light. Light and 
 electricity are, in fact, merely different manifestations 
 of waves in a universal medium, the undulations in the 
 case of visible light being from about one thirty- 
 thousandth to one sixty-thousandth of an inch in length, 
 while the waves used in wireless telegraphy may be 
 from one foot to one thousand feet long, from crest to 
 crest. 
 
 Soon after Hertz had described his remarkable 
 researches on the production and detection of electro- 
 magnetic waves, the scientific world realised their import- 
 ance. It was pointed out that as Hertzian waves possess 
 the property of passing through fog or material obstacles 
 they could be used for a system of wireless telegraphy. 
 Among the men of science who saw clearly the pos- 
 sibilities of the application of the waves for this purpose 
 was Sir William Crookes, who, writing on Hertz's 
 work in The Fortnightly Review of February, 1892, 
 said : 
 
 Here is unfolded to us a new and astonishing world one 
 which it is hard to conceive should contain no possibilities of 
 transmitting and receiving intelligence. Rays of light will not 
 pierce through a wall, nor, as we know only too well, through a 
 London fog. But the electrical vibrations of a yard or more in 
 wave length will easily pierce such medium, which to them will 
 be transparent. Here, then, is revealed the bewildering possi- 
 
xi ACROSS THE BORDER 297 
 
 bility of telegraphy without wires, posts, cables, or any of our 
 present costly appliances. Granted a few reasonable postulates, 
 the whole thing comes well within the realms of possible fulfil- 
 ment. Sir William Grookes. 
 
 The receiver used by Hertz was not suitable for tele- 
 graphic work, but a more practicable form was soon 
 found, and was used in a lecture delivered by Sir Oliver 
 Lodge before the Royal Institution in 1894, when the 
 statement was made that the apparatus would respond 
 to signals at a distance of half a mile. Two years later, 
 Mr. Marconi filed a provisional specification of apparatus 
 for signalling by means of electric waves. 
 
 Mr. Marconi not only saw that the laboratory experi- 
 ments of Hertz might be put to practical use, but also 
 proceeded to adapt them to a system of telegraphy 
 through the ether. As the radiator of electric waves 
 he introduced a long vertical wire, broken by a spark 
 gap, so that the pulses could surge up the wire and down 
 into the earth, sending waves out into the ether in all 
 directions as they did so. He constructed a more 
 sensitive and trustworthy instrument to detect the 
 waves, and ascertained what energy was required to 
 make it possible to signal over any distance. To his 
 knowledge, confidence and daring must be ascribed 
 the commercial development of wireless telegraphy. 
 By experiments carried out on Salisbury Plain, he first 
 succeeded in transmitting messages over a distance of 
 two miles ; in 1898 he sent messages from Poole to Alum 
 Bay, Isle of Wight a distance of eighteen miles ; and 
 by 1910 he was able to produce electric waves so powerful 
 that their influence could be detected, and signals read, 
 at a distance of six thousand miles. This remarkable 
 performance,which suggests marvellous possibilities for 
 the future, was achieved as the direct outcome of the 
 
298 DISCOVERY CH. 
 
 scientific work of Hertz, Maxwell, Faraday and Henry. 
 As Mr. Marconi himself acknowledged in 1900 : 
 
 The experimental proof of Hertz, thirteen years ago, of the 
 identity of light and electricity, and the knowledge of how to 
 produce, and how to detect, these ether- waves, the existence of 
 which had been so far unknown, made possible wireless tele- 
 graphy. G. Marconi. 
 
 Wireless telegraphy has become part of our everyday 
 life. The waves conceived by a mathematician and 
 demonstrated in a physical laboratory are now con- 
 tinually carrying messages across the sea and land. 
 From the Admiralty Offices at Whitehall the ether 
 invisible, intangible, immaterial is set vibrating, and 
 its tremors awaken sympathetic response in instruments 
 on warships hundreds of miles away. Ships in distress, 
 if equipped with the means of producing Hertzian 
 waves, can send their call for help into the darkness. 
 Their throbbing plea goes out in ever-widening circles, 
 like the waves formed when a stone is dropped into a 
 placid lake, so that any vessel with wireless telegraphy 
 apparatus which comes within their sphere of influence 
 will respond to it and hasten to the rescue. 
 
 The first notable instance of the use of this wireless 
 message in saving life at sea occurred in January, 1909, 
 when the ocean liner Republic collided with the Florida 
 in a dense fog. The Republic's operator, Mr. Jack Binns, 
 was in his cabin at the time of the collision, and immedi- 
 ately sounded the wireless signal of distress. The sides 
 of the cabin were shattered by the shock, and the ship 
 was plunged in darkness, but the wireless apparatus 
 remained intact, and he remained at the instruments 
 flashing into the fog the cry, " Am in distress and need 
 assistance," and when it had been answered, notifying 
 the position in which the sinking ship would be found. 
 
xi ACROSS THE BORDER 299 
 
 He was first able to communicate with the wireless 
 station at Siasconsett, Massachusetts, which in turn 
 sent the news of the distress of the Republic to the Baltic, 
 the Lorraine and other vessels equipped with the 
 Marconi apparatus. The dense fog hindered the speedy 
 approach of the relieving vessels, but at last the Baltic 
 came within reach, and succeeded in rescuing the whole 
 of the imperilled passengers and crew of the sinking ship. 
 
 A few months after the wreck of the Republic, all the 
 passengers and crew of another ocean liner, the Slavonia, 
 which had been stranded on the South-west of Flores 
 Island, were rescued by a vessel which had heard the 
 call for help when at a distance of 180 miles, and turned 
 back at once to give assistance. But the most dramatic 
 use of wireless telegraphy at sea occurred in April, 1912, 
 when the Titanic, the largest vessel in the world, struck 
 an iceberg on her maiden voyage from Southampton to 
 New York. She was installed with Marconi instruments 
 having a sphere of influence of about five hundred miles 
 by day and treble that distance at night. Several 
 vessels heard the wireless appeal for help, but none was 
 able to reach her before she foundered, four hours after 
 collision with the iceberg. When the relieving vessels 
 reached the scene of the disaster they were able to rescue 
 nearly nine hundred survivors, who had taken to the 
 boats, but the remainder of the human freight of more 
 than two thousand souls had found a grave with the 
 Titanic in the waters of the Atlantic. The only bright 
 spot in this sorrowful history is that the passengers and 
 crew in the crowded boats owe their lives to wireless 
 telegraphy, which summoned the vessels that saved them. 
 
 One further impressive instance of the aid rendered 
 by this development of science is that of the steamship 
 Volturno, which was destroyed by fire in mid- Atlantic 
 
300 DISCOVERY CH. 
 
 in October, 1913, during a heavy gale. The wireless 
 telegraphic call for help was first received by the Car- 
 mania, which immediately made use of her wireless 
 installation to spread it far and wide, with the result 
 that ten steamships hurried to the burning vessel and 
 were able to save all the people more than five hundred 
 who had remained on board. 
 
 The maximum distance at which a light can be seen 
 depends upon the brightness of the light and the sensitive- 
 ness of the eye. A light of twelve candle-power is 
 visible at a distance of five miles, and for it to be seen at 
 a distance of 100 miles it would have to be nearly five 
 thousand candle-power. In wireless telegraphy the 
 transmitting station sends out electric waves precisely 
 similar to the waves which produce the sensation of 
 sight, but they are invisible and have to be detected by 
 sensitive receiving instruments instead of the eye. 
 These detectors have reached such a degree of perfection 
 that they are of the same order of sensitiveness as the 
 human eye. 
 
 Expressed in terms of energy, we may say that the 
 light which can just be seen by the eye, the sound which 
 can just be heard by the ear, and the electric wave 
 which will just affect a receiver, is of the same intensity. 
 If, therefore, energy could be radiated at the same rate, 
 either as waves of sound in the air, or as waves of light, 
 or as the longer electric waves, we should be able to 
 detect them at approximately the same distance by 
 means of our ears, or our eyes, or a wireless telegraphy 
 receiver. When we speak, our voice is heard and under- 
 stood by those who listen to us ; and if we could speak 
 with the same energy as that of the transmitting appara- 
 tus of a wireless telegraphy station, the ear would be 
 able to detect the sound at about the same distance as 
 
xi ACROSS THE BORDER 301 
 
 that at which, a wireless receiver is affected. The energy 
 of the vibrating air acting upon the drum of the ear in the 
 case of the faintest audible sound is about the same as 
 that falling upon the retina of the eye from the faintest 
 visible star. The energy of the loudest sound which 
 can be distinguished (at the point when the ear cannot 
 decide which of two tones is the louder) has been esti- 
 mated to be about as much as that involved in the 
 growth of a single blade of grass in June. 
 
 " Communication by wireless telegraphy is very 
 wonderful," once remarked a lady to Mr. Marconi. " It 
 is not half so wonderful as our conversing together now," 
 modestly replied the inventor ; and he was right. The 
 production of sounds by the organs of speech, their 
 transmission by waves in the air, and their appreciation 
 by the organs of hearing, involve infinitely more com- 
 plicated actions than are concerned in producing electric 
 waves at one station and detecting them hundreds or 
 thousands of miles away. 
 
 It is not possible here to refer to the further develop- 
 ments of wireless telegraphy. Already the messages 
 sent out from the Eiffel Tower and other high-power 
 stations can be read with instruments which can be 
 carried in the pocket and connected to an iron railing 
 or gate ; and human speech has been conveyed by wire- 
 less telephony from Arlington (Virginia) to Mare Island 
 (California) a distance of 2500 miles ! With such 
 remarkable achievements to command our admiration, 
 who will have the temerity to assign limits to what will 
 be accomplished by science in the future ? 
 
 Next to wireless telegraphy, the discoveries of science 
 which seem the most wonderful to most people are 
 those of Rontgen rays and radium. When in 1895 the 
 announcement was made that Prof. Rontgen, then of 
 
302 DISCOVERY CH. 
 
 Marburg University, had discovered rays which would 
 pass through opaque substances, such as wood or the 
 human body, more easily than through a glass, it was 
 scarcely believed. The observation was, however, only 
 a natural consequence of scientific work done by earlier 
 investigators. 
 
 It had been known for many years previously that 
 when an electric discharge is caused to take place 
 through a sealed glass tube or bulb containing only 
 extremely rarefied air, the tube becomes filled with a 
 beautiful luminosity. Sir William Crookes made a 
 number of experiments with vacuum-tubes of this kind 
 after reducing the air in them to the highest degree of 
 rarefaction. He found that electrified particles seemed 
 to be shot out from one of the two slips of metal sealed 
 into the tube for connection with the machine which 
 produced the electricity. Diamonds, rubies and other 
 substances, when placed in the tube so that these par- 
 ticles or rays fell upon them, became phosphorescent, 
 and emitted a shimmering light. When a pattern was 
 cut out of a sheet of mica and placed in the path of the 
 rays, it stopped them, the result being that a dark 
 shadow of the pattern was seen at the end of the tube 
 opposite that from which they were projected, while 
 all round the shadow was phosphorescent light. 
 
 Hertz, who first demonstrated the existence of electric 
 waves, showed that the rays would pass through thin 
 sheets of certain metals ; hence, a pattern made of one 
 of these metals, and placed in a vacuum-tube in the 
 same way as the mica pattern, produced no shadow, 
 for, though opaque to light, they were transparent to 
 Crookes's rays. This was a decided step in advance, 
 and the next was taken by Prof. Lenard, in 1894, who, 
 by using a vacuum-tube having an aluminium end or 
 
xi ACROSS THE BORDER 303 
 
 window, was able to pass the rays out into the air, 
 without reducing their properties of producing phos- 
 phorescence. He further showed that the rays thus 
 set free from their bondage in a vacuum were capable 
 of recording their existence upon a photographic plate. 
 Evidently all that was necessary to be done in order to 
 utilise this knowledge was to elaborate the experiments 
 by placing various substances in the path of the rays 
 and catching their shadows upon a sensitised photo- 
 graphic plate. This is what Prof. Rontgen did, but he 
 found also that the aluminium window was unnecessary ; 
 for the rays escape through glass. 
 
 A vacuum-tube rendered luminous by the electric 
 discharge, was surrounded by Prof. Rontgen with a 
 shield of black paper in a completely darkened room. 
 A piece of paper, having one side covered with a phos- 
 phorescent substance, was brought into the neighbour- 
 hood of the tube, and found to become brilliantly 
 luminous, in spite of the fact that the light of the vacuum- 
 tube was covered up. This proved beyond doubt that 
 certain rays can pass through paper, and still possess 
 the ability to produce fluorescence. A book of 1,000 
 pages did not prevent this action, nor did two packs 
 of cards, thick blocks of wood, or ebonite, while a 
 sheet of aluminium nearly an inch thick only reduced the 
 effect. Plates of copper, silver, lead, gold and platinum 
 permitted the rays to pass, but only when they were 
 thin. When the hand was held between the vacuum- 
 tube and the fluorescent screen, the shadow showed 
 the bones darkly, with only faint outlines of the sur- 
 rounding flesh, the reason being that the bones 
 are almost opaque to the active rays, while the flesh 
 is transparent to them. By substituting a sensitive 
 plate for the fluorescent screen, a photograph could, 
 
304 DISCOVERY CH. 
 
 therefore, be obtained, showing the internal structure 
 of the hand or other parts of the human body. 
 
 These properties of X-rays seemed very wonderful 
 when they were first made known ; but, as we have 
 seen, their discovery was only a natural consequence 
 of earlier scientific work. Without Sir William Crookes's 
 investigations on the electric discharge in high vacua, 
 there would have been no Crookes's tube and no X-rays. 
 Rontgen suspected that an excited Crookes's tube would 
 cause fluorescence, that is, make certain substances 
 shine faintly ; and he noticed that paper covered with 
 a certain substance did show a faint shimmer when the 
 tube was in action, although the tube was covered so 
 that no light could be seen from it. Many other people 
 had used the tubes for lectures and experiments, and the 
 effects visible in it are so beautiful that it is not strange 
 that attention was concentrated upon them. It would 
 have seemed strange at that time to cover up a luminous 
 tube and look not at its own brilliant colours, but at 
 something else, yet that is what Rontgen did, and he 
 found that the unseen rays emitted by the tube were of 
 far greater interest than those which affected the human 
 retina. 
 
 Most of the tubes now used for the production of X-rays 
 are modifications of the " focus tube " devised by Prof. 
 Herbert Jackson, of King's College, London, for the 
 study of phosphorescence, before Rontgen's discovery 
 was announced. Prof. Jackson might have made a 
 fortune by patenting his invention, but he decided 
 deliberately not to do so, and for the sake of scientific 
 knowledge left his device unprotected. In thus sacrific- 
 ing personal profit to scientific needs, he manifested a 
 spirit which the commercial world may appreciate but 
 cannot understand. 
 
xi ACROSS THE BORDER 305 
 
 After the discovery of Rontgen rays, their application 
 to medicine was soon seen ; and now there is scarcely a 
 hospital but makes use of the rays, not only for the 
 examination of inner parts of the body, but also for 
 treatment of certain diseases. The use of the rays to 
 show the position of embedded needles or other foreign 
 objects in the body, or to reveal fractures or dislocations 
 of bones, is obvious, but the extension of this method 
 of diagnosis has been even more valuable to the physician 
 than to the surgeon. Improvements in apparatus and 
 methods have made it possible to show, not only the 
 outlines of the bones, but also minute details of their 
 structure ; and more than this, a considerable amount 
 of detail of the internal soft parts of the human body 
 can now be examined by means of the rays. It is quite 
 easy to estimate in this way the size, shape and position 
 of the heart, to detect the earliest stages of congestion 
 of the lungs due to phthisis, to prove beyond doubt and 
 with perfect safety, whether a calculus (stone) is present 
 in either kidney, and to study the digestive canal 
 throughout its length. 
 
 For this last purpose, the patient sits upright and 
 drinks a harmless dose of carbonate of bismuth. This 
 fluid is opaque to Rontgen rays, so that the shadow 
 thrown by it can be seen upon a fluorescent screen. 
 The passage of the fluid from the mouth to the stomach 
 can, therefore, be observed upon the screen ; and any 
 obstruction in the food- pipe or deviation from the normal 
 course at once becomes apparent. The regular con- 
 tractions of the stomach by means of which the food 
 is expelled into the small intestine may be observed, 
 and a few hours later the course can be traced through 
 the large intestine. Before this development of dia- 
 gnostic methods, irregularities and obstructions in the 
 G.D. u 
 
306 DISCOVERY CH. 
 
 digestive system were largely a matter of conjecture ; 
 and an operation was necessary to discover the exact 
 origin of the disorder. Rontgen rays enable almost the 
 whole of the internal anatomy to be scrutinised and 
 photographed, so that no operation need be undertaken 
 until its necessity has been demonstrated by ocular 
 evidence. 
 
 The beneficial uses of X-rays are alone sufficient to 
 make the discovery of the highest significance in the 
 history of humanity ; but advance has not been limited 
 to them. The discovery directed renewed attention to 
 the subject of phosphorescence and fluorescence, and the 
 field thus opened up has proved to be the richest ever 
 explored. 
 
 Certain substances, such as salts of uranium, phos- 
 phoresce, or continue to shine, after Rontgen rays have 
 been permitted to fall upon them. In 1896 Henri 
 Becquerel found that uranium salts which had been 
 made phosphorescent by exposure to sunlight gave out 
 rays having similar properties to those discovered by 
 Rontgen ; that is, they could pass through materials 
 opaque to ordinary light, would affect a photographic 
 plate, and so on. Further investigations showed that 
 these functions are inherent in uranium and its com- 
 pounds, which are thus independent of the exciting 
 influence of Rontgen rays or sunlight. Similar pro- 
 perties were shortly afterwards found by Schmidt to be 
 possessed by thorium ; and then Prof, and Madame 
 Curie, by infinite labour, succeeded in isolating from 
 pitchblende two new substances, radium and polonium, 
 which were far more active in their radiations than any 
 others. The discovery of actinium by Debierne quickly 
 followed, and, said Sir J. J. Thomson, in 1909 : " Now 
 the researches of Rutherford and others have led to the 
 
xi ACROSS THE BORDER 307 
 
 discovery of so many new radioactive substances that 
 any attempt at christening them seems to have been 
 abandoned, and they are denoted, like policemen, by the 
 letters of the alphabet." 
 
 It is an axiom of scientific theory that you cannot 
 create energy any more than you can add or destroy a 
 single atom of matter in the universe. If light or heat 
 are being given out in any way, energy is being expended 
 to produce it, and the same is true of other effects. 
 Radium, however, is a spontaneous producer of light, 
 heat and electricity ; in other words, it continually 
 produces luminous, thermal and electrical effects with- 
 out using up energy capable of being measured. 
 Unlike ordinary phosphorescent substances, which only 
 shine after exposure to light, radium is luminous over 
 its whole mass, and the luminosity does not diminish at 
 any time. Moreover, radium salts give off heat con- 
 tinuously, without any chemical change such as occurs 
 in ordinary combustion ; and the amount of heat is 
 sufficient to keep the temperature of the radium salts 
 nearly three degrees Fahr. above that of their 
 surroundings. 
 
 It is believed that the rays emitted by a radioactive 
 substance represent the results of the breaking-up of 
 atoms of the substance, and mark, therefore, stages of 
 atomic disruption. Radium, for example, gives off a 
 gas called " radium emanation " by the first observers, 
 Sir Ernest Rutherford and Prof. F. Soddy which repre- 
 sents the product of the disruption of radium atoms. 
 On this view, which is based upon substantial experi- 
 mental investigation, there must be a limit to the life 
 of a radioactive element. In the case of radium, 
 one grain would be reduced to half a grain in -1760 
 years ; but the emanation has a much shorter span 
 
308 DISCOVERY OH. 
 
 of life, for its activity is reduced by one-half in four 
 days. 
 
 When first collected, radium emanation is more ener- 
 getic than radium itself, and will produce precisely the 
 same effects ; but it runs through its stock of energy in 
 a few weeks, whereas the activity of radium remains 
 practically unaltered for hundreds of years. Suppose a 
 ton of coal could be kept burning in a furnace continu- 
 ously for about two thousand years, then it would pro- 
 duce approximately the same energy as would be given 
 out by one gram (15 grains) of radium in the same 
 period. If the rate of atomic disruption could be 
 increased, and the life of radium therefore reduced, the 
 rate of output of energy would be proportionally greater. 
 
 An illustration of the magnitude of the energy which 
 might thus be obtained has been given by Sir William 
 Ramsay. " Suppose," he said, " that the energy in a 
 ton of radium could be utilised in thirty years, instead 
 of being evolved at its invariable slow rate of 1760 years 
 for half-disintegration, it would suffice to propel a ship 
 of 15,000 tons, with engines of 15,000 horse-power, at the 
 rate of 15 knots for thirty years practically the life of 
 the ship. To do this actually requires a million and a 
 half tons of coal." 
 
 When radium from which the emanation has been 
 collected by suitable means is left to itself for about a 
 month, it 'recovers completely its original condition, and 
 a fresh supply of emanation can be obtained from it. 
 In cases, therefore, where radium is required for any 
 purpose, but cannot be procured on account of its high 
 price, radium emanation provides a cheap substitute 
 possessing all the properties of its parent. Like the 
 widow's barrel of meal and cruse of oil, radium wasteth 
 not, neither does it fail, though a supply of emanation 
 
xi ACROSS THE BORDER 309 
 
 is taken from it every few weeks. It may be likened 
 also to Draupnir, the ring of Odin, which, after being 
 placed by him upon the pile of his son Baldur, acquired 
 the power of dropping every ninth night eight rings of 
 equal weight with itself. 
 
 Whatever may be the atomic changes by which the 
 energy manifested by radioactive substances can be 
 explained, we have the fact that radium salts continually 
 produce sufficient light to be observed readily in semi- 
 darkness, heat enough to be appreciably warmer than 
 other objects near them, rays which have an energetic 
 action upon photographic plates and by which radio- 
 graphs can be taken, and emissions which blister the 
 skin and produce other remarkable physiological effects. 
 It is, perhaps, fortunate that the new element is probably 
 the rarest in the universe. Pitchblende, from which 
 radium is obtained, is comparatively rare, and only 
 about one and a half grains of a radium salt can be 
 extracted from a ton of pitchblende ore. 
 
 Rontgen rays, radium and radium emanation are all 
 now largely used by physicians, not merely as means of 
 diagnosis, but for curative purposes. Early experimenters 
 with Rontgen rays did not realise the extraordinary 
 powers of the rays to produce virulent effects upon the 
 skin long exposed to them. The X-ray burns thus caused 
 are most intractable, and usually the hand or arm badly 
 affected by them has to be removed to prevent further 
 extension or death. Odin bought for himself wisdom 
 at the price of his right eye, but it was Tyr who, among 
 all the Aesir, was held by the Norns or Fates of northern 
 myths to be worthy of the highest honour, for he sacri- 
 ficed his strong right hand not for himself but for others. 
 This is what was cheerfully done by several early workers 
 with X-rays, notably Dr. Blacker, of St. Thomas's 
 
310 DISCOVERY OH. xi 
 
 Hospital, and Mr. Harry W. Cox, who were the first 
 martyrs of the rays, and Dr. Hall Edwards, whose left 
 arm had to be removed. Mankind should not forget 
 the names of these and other experimenters by whose 
 sufferings increased knowledge has been attained. 
 
 Operators with X-rays now protect themselves from 
 injury by using screens which shield them, but in the 
 early days the necessity for such precautions was not 
 understood. The rays are now kept under control, and 
 their power of affecting animal tissue is used to cure 
 instead of being harmful. In certain diseased conditions, 
 local application of Rontgen rays has been used with 
 marked success, and the field of their utility will certainly 
 extend as improvements are effected in their technique. 
 Radium has proved to be a valuable agent for the 
 removal of certain ulcers and small cancerous growths, 
 but neither it nor X-rays can at present be looked upon 
 as a cure for cancerous growths of large size. In many 
 cases, radium emanation is more convenient to use than 
 its parent ; for it can be inhaled, and when dissolved 
 can be injected into the body tissues, or swallowed. We 
 are only just beginning to learn something of the bio- 
 logical significance of the new rays ; and no one can yet 
 predict with confidence the beneficial action which the 
 next generation will discover in them. 
 
CHAPTEK XII 
 
 TOWARDS INFINITY 
 
 Go, speed the stars of thought 
 
 On to their shining goals. Emerson. 
 
 God has placed no limits to the exercise of the intellect He has 
 given us on this side of the grave. Francis Bacon. 
 
 The heavens are calling you, and wheel around you, 
 
 Displaying to you their eternal beauties, 
 
 And still your eye is looking on the ground. Dante, 
 
 A thorough advocate in a just course, a penetrating mathe- 
 matician facing the starry heavens, both alike bear the 
 semblance of divinity. Goethe. 
 
 Trees in their blooming, 
 Tides in their flowing, 
 Stars in their circling 
 
 Tremble with song, 
 God on His throne is 
 Eldest of poets : 
 Unto His measures 
 
 Moveth the whole. W. Watson. 
 
 WHEN the stars sparkle upon the azure canopy of heaven, 
 the human mind seeks silence and solitude to contem- 
 plate them. It is upon such an occasion that man realises 
 he is face to face with infinity ; and, as his soul is uplifted, 
 a sense of helplessness fills him, and the spirit of David 
 makes him ask of his Creator, " What is man, that thou 
 art mindful of him ? and the son of man, that thou 
 visit est him ? " 
 
312 DISCOVERY OH. 
 
 If these devout thoughts inspired the Psalmist when 
 he considered the heavens, what words are now adequate 
 to express the feelings to which increased knowledge of 
 the universe should give rise ? Less than three thousand 
 stars can be seen when a watcher, unaided by optical 
 power, looks upward on the finest night ; but even a 
 small telescope or field-glass will show many times this 
 number. With the great lenses which are directed 
 heavenward in these days, it is possible to see one hundred 
 million stars in the whole celestial sphere, instead of the 
 few thousand visible to the naked eye. 
 
 Carry your mind back to pre-telescopic times, and 
 consider what was then conceived to be the content and 
 extent of the universe visible to man. Nothing could 
 be known of the stars and other celestial objects beyond 
 the range of unaided vision, and not the boldest of the 
 speculative philosophers imagined that there were 
 millions of celestial bodies in addition to those which 
 were within their bounds of knowledge. What they saw 
 seemed to be the beginning and end of things celestial, 
 and there was no thought of anything beyond it. 
 
 Astronomy, more perhaps than any other science, 
 teaches the imperfection of human understanding, and 
 hesitates to set limits to the planes which may be attained 
 in the future. Celestial things are rarely what they seem. 
 A brilliant sky at night gives the impression of infinite 
 calm and peace, and we speak of the " fixed " stars, 
 whereas not a single one is at rest, and many are moving 
 through space with velocities greatly in excess of any 
 express train on the Earth. It is difficult also for anyone 
 unacquainted with astronomy to believe that the Earth, 
 and other members of the Solar system, in addition to 
 their movement of revolution around the Sun, are being 
 carried by the Sun into unknown regions of space at 
 
xii TOWARDS INFINITY 313 
 
 the rate of nearly a million miles a day, yet that is 
 certainly the case. 
 
 Through every year, every hour, every minute of human 
 history from the first appearance of man on the earth, from the 
 era of the builders of the Pyramids, through the times of Caesar 
 and Hannibal, through the period of every event that history 
 records, not merely our earth, but the sun and the whole solar 
 system with it, have been speeding their way towards the star 
 Vega, on a journey of which we know neither the beginning nor 
 the end. During every clock-beat through which humanity has 
 existed, it has moved on this journey by an amount which we 
 cannot specify more exactly than to say that it is probably 
 between five and nine miles per second. We are at this moment 
 thousands of miles nearer to Vega than we were a few minutes 
 ago ; and through every future moment, for untold thousands 
 of years to come, the earth and all there is on it will be nearer 
 to that star, or nearer to the place where the star now is, by 
 hundreds of miles for every minute of time come and gone. 
 When shall we get there ? Probably in less than a million years ; 
 perhaps in half a million. We cannot tell exactly ; but get 
 there we must if the laws of Nature and the laws of motion 
 continue as they are. To attain to the stars was the seemingly 
 vain wish of the philosopher ; but the whole human race is, 
 in a certain sense, realising this wish as rapidly as a speed of 
 six or eight miles a second can bring it about. Prof. Simon 
 Newcomb. 
 
 The Sun itself deceives us by its appearance ; for 
 what we see of it is relatively small in comparison with 
 the vast sheets and rays of luminous matter that sur- 
 round the brightly visible disc, and are revealed only 
 during a total eclipse. If the Sun could be seen from a 
 point outside the Earth's atmosphere, it would appear 
 more blue than the yellow tint with which we are 
 familiar. Surrounding this bluish ball would be seen a 
 brilliant scarlet layer like a sea of flame, from five 
 thousand to ten thousand miles deep, out of which 
 enormous masses of incandescent gas would be tossed 
 
314 . DISCOVERY OH. 
 
 from time to time to heights of tens or hundreds of 
 thousands of miles. The manifestation of such tremen- 
 dous energy would produce fear rather than the calm 
 assurance which at present exists as to the constancy of 
 the Sun's condition. 
 
 Because the total amount of heat received annually 
 from the Sun has not varied appreciably for the past 
 two thousand years or so, we are accustomed to assume 
 that this uniformity will be maintained. But as almost 
 nothing is definitely known as to the source of the Sun's 
 heat, this belief in a continuity of the present conditions 
 is purely a matter of faith that the future will be as the 
 past. Atomic, or other changes may occur at any time 
 which would raise or lower the Sun's temperature 
 sufficiently to have a profound influence upon the 
 Earth. Any large variation of this kind would com- 
 pletely change the face of the world ; and a decrease 
 of 'ten per cent, in the amount of solar heat received 
 would convert the temperate regions into frozen wastes. 
 
 Observations made in recent years have shown that 
 at times the Sun does radiate more heat than at others, 
 the amount fluctuating by about ten per cent, during 
 irregular periods of from five to ten days' duration. 
 These changes are possibly due to local differences of 
 temperature on the Sun, but they may become general 
 and progressive in one direction or another. In fact, 
 though theoretical considerations suggest that the Sun's 
 heat will remain practically constant for millions of 
 years, no one can state decisively that it will do so for a 
 hundred years. 
 
 Astronomy thus gives no support to the mind that 
 uses the knowledge existing at any epoch as if it were a 
 complete inventory of the universe. We can reason 
 about things known to exist, but we must remember 
 
xii TOWARDS INFINITY 315 
 
 that beyond the phenomena which have so far been 
 brought within the range of our senses there may be 
 many others awaiting to be revealed by more potent 
 or refined means of observation, or new methods of 
 inquiry. During the past few years, for example, the 
 conviction has been forced upon astronomers that there 
 are probably more dark stars than bright ; and that 
 completely blank regions here and there in the sky 
 represent immense clouds of non-luminous cosmic dust 
 which blot out the light of stars behind them. 
 
 Masses of material have been revealed by photography 
 which are beyond the visual reach of the largest tele- 
 scopes ; many bright stars have been found to possess 
 acolytes ponderous enough to influence their movements 
 but without intrinsic luminosity ; and the millions of 
 meteoritic particles which enter the earth's atmosphere 
 daily, producing the appearance of shooting stars or 
 meteors, show that space should not be regarded as a 
 void, but rather as a plenum of dead matter. 
 
 It is easy to understand that as the power of seeing is 
 enlarged by the improvement of instruments or the 
 development of methods of inquiry, new spheres are 
 brought within the range of human knowledge. Our 
 eyes have in truth been opened by the lenses of giant 
 telescopes, and we have come to know that greatness 
 is not to be measured by visibility. For not only are the 
 stars revealed by telescopes vastly more numerous than 
 those bright enough to be seen by the naked eye, but 
 they also contribute more to the total quantity of star- 
 light received by the earth than the brilliant objects 
 which make a view of the midnight sky an impressive 
 sight. As it is estimated that three-quarters of the total 
 starlight that reaches this world of ours is from stars 
 beyond the grasp of unaided vision, it is not difficult to 
 
316 DISCOVERY CH. 
 
 understand that what we see is only a limited view of the 
 universe. 
 
 The astronomical evidence for the existence of invisible 
 bodies in the universe is not a matter of assertion, but 
 of interpretation of results based upon scientific inquiries. 
 Effects are measured and are referred to physical causes 
 which account for them in every detail, though the exact 
 mechanism of the action may not be understood. Galileo 
 discovered the laws of motion of falling bodies, and 
 Newton showed that the law of gravitation is sufficient 
 to prescribe the movements of the moon or a planet as 
 precisely as it does for the fall of a pebble to the earth, 
 yet the nature of gravitational attraction remains a 
 mystery still. 
 
 From such a familiar case of relationship between fact 
 and inference as is afforded by a falling stone, it is easy 
 to pass to larger effects of gravitational action. For those 
 who have little faith in intangible evidence, the discovery 
 of the planet Neptune may be put in as a plea for con- 
 fidence in conclusions based upon it. The observation of 
 this planet in 1846 close to the position which mathe- 
 matics based on the law of gravitation had assigned to 
 it, afforded a striking instance of the ability of the law 
 to respond to any demands which could be made upon 
 it in the solar system. 
 
 The planet Neptune happened to be an object bright 
 enough to be seen with telescopic aid, though it is quite 
 invisible to the naked eye. If no telescope had existed 
 when this new member of our system was discovered, the 
 actual test of the validity of the mathematical results 
 could not have been made the processes of the intricate 
 mathematical argument would have touched the planet 
 and followed its movements, but, in the absence of 
 ocular demonstration, the conclusion that a massive 
 
xii TOWARDS INFINITY 317 
 
 object existed beyond Uranus would have been regarded 
 as an interesting statement which remained to be 
 proved. 
 
 Another case in which the existence of an unknown 
 mass was suspected before the body itself was seen is 
 that of the Dog Star, Sirius. This star the brightest 
 in the heavens is moving through space, as, indeed, 
 all stars are, but its change of position is not uniformly in 
 one direction. The difference is very slight, and requires 
 good instrumental means to detect it, but it could not be 
 disregarded when once it had been established, and an 
 explanation had to be found for it. This was given by 
 Bessel in 1844, who suggested that a dark body near 
 Sirius was exerting an influence upon its movements. 
 Referring to the matter in a letter to Sir John Herschel, 
 he wrote, " Light is no real property of mass. The 
 existence of numberless visible stars can have nothing 
 against the existence of numberless invisible stars," and 
 upon this idea he based the opinion that Sirius was a 
 double star consisting of an invisible body as well as the 
 visible one, the two forming a couple united by the bonds 
 of gravitation. At that time it seemed scarcely credible 
 that there were stars which could not be seen as well as 
 those revealed by the telescope, but Bessel's belief has 
 since received ample justification. Twenty years after 
 he had given expression to it a faint star was discovered 
 near Sirius, and it proved to be the body which causes 
 the bright star to swerve from a straight path. 
 
 Stars with bright companions were discovered by Sir 
 William Herschel towards the end of the eighteenth 
 century, and their majestic march around one another 
 was recorded. Many of these twin suns are nearly equal 
 in brightness, but in most cases the two stars are badly 
 matched in regard to visual appearance, a brilliant star 
 
318 DISCOVERY CH. 
 
 often being joined by the force of mutual attraction to 
 one several degrees fainter. In the star Sirius this 
 difference is accentuated to a noteworthy amount ; for 
 while it is the brightest object in the stellar universe, its 
 companion is so faint that it can be seen only by using 
 telescopes of great light-grasping power. 
 
 There is really nothing strange in this disparity when 
 the matter is logically considered. Why should we 
 measure mass in the universe by what we are able to 
 detect with our limited optical sense ? To a blind man, 
 or to an eye capable of seeing everything, the brilliant 
 star Sirius would not seem so overpoweringly great by 
 the side of the dark heavy body to which it is united ; 
 and if mortals possessed a sense capable of being affected 
 in proportion to substance, as the sense of sight is by 
 luminosity, the dark body would have been noticed as 
 soon as man turned his face towards the skies. For 
 though the faint star now seen to accompany Sirius 
 would need to have its brightness increased twelve 
 thousand times to equal the brilliancy of that gem of the 
 sky, it is nearly half as heavy when measured by the 
 standard of mass. 
 
 There are other cases in which the companions of 
 bright stars are very faint, but heavy out of all pro- 
 portion to their brightness. As with Sirius, the astro- 
 nomer Bessel expressed the conviction that Procyon, 
 which rises about half an hour before it, had a dark 
 companion, disturbing its movements. Half a century 
 later, in 1896, this companion was detected by Prof. 
 Schaeberle, so we have here another example of a body 
 known to exist long before it was seen. 
 
 The difference between mass and luminosity accounts 
 for the interval that elapsed between prediction and 
 discovery of each of the cases mentioned. The com- 
 
xii TOWARDS INFINITY 319 
 
 panion of Procyon has a mass more than half as great 
 as that of our sun, and is, therefore, capable of exerting 
 appreciable gravitational influence upon a body near it. 
 But though it is such a ponderous globe, its light is much 
 less than that which the sun would give if placed in the 
 same position among the stellar host. It is therefore 
 not surprising that the gravitational influence was 
 detected before the faint glimmer of the rays from the 
 star was seen and understood. 
 
 Three instances have now been mentioned in which 
 invisible celestial bodies were found by indirect evidence 
 before they were looked for with telescopic aid we 
 refer to the planet Neptune, and the companions of 
 Sirius and Procyon. Predictions fulfilled in this way 
 should encourage confidence in conclusions based upon 
 similar premises. That is to say, if observations show 
 that a star is not moving through space in a straight line, 
 they afford presumptive evidence of the existence of one 
 or more bodies near it. The problem thus resolves itself 
 into one of studying stellar motions. 
 
 A comparison of the exact positions of stars year by 
 year shows that every one has a motion of its own across 
 the blue background of infinity. The amount of move- 
 ment as seen from the earth is very minute, and can only 
 be detected by accurate determinations of position, but 
 it is none the less real, and has to be taken into account 
 in precise astronomy. Every movement has a cause, and 
 when deviations from a direct course are found, it is 
 certain that the star showing them is being disturbed by 
 a massive body which may or may not be visible. 
 
 But what of stars which are moving straight towards 
 the earth or away from it ? Such movements cannot 
 produce any change of position upon the background 
 upon which they are projected. This is true enough, 
 
320 DISCOVERY OH. 
 
 but they can be detected by other effects. To an astro- 
 nomer with a spectroscope, the light of a star is a gamut 
 of colour crossed by dark or light rays comparable with 
 musical notes. Just as the pitch of a note can be 
 raised or lowered by rapid motion of the sounding body 
 towards or away from the listener, so the positions of rays 
 in the light-scale are affected by similar movements of 
 approach or recession. If the distance between the 
 moving star and the earth is decreasing, the rays analysed 
 by the spectroscope are increased in colour pitch, and if 
 the distance is increasing the rays are moved towards the 
 lower end of the gamut of light, or, expressed in the 
 terms of music, their notes are flat. So perfect a means 
 does the spectroscope provide of measuring the move- 
 ment, back or forth, that the velocity of a star can be 
 determined within a quarter of a mile a second, though 
 the star itself may be at an immeasurable distance from 
 usf Here, then, we are provided with another means 
 of studying stellar motions, and to it we owe the proof 
 of the existence of many dark stars. 
 
 That such dark stars existed was first suggested by 
 John Goodricke, who, though deaf and dumb from birth, 
 used his sight to such good effect that his name is 
 renowned among astronomers. He died at the early age 
 of twenty-two, yet his observations, made in a small 
 observatory at York, obtained for him in 1783 the 
 Copley Medal of the Royal Society, the highest honour 
 which the Society can confer. Goodricke was the first 
 to make a systematic study of the variations in bright- 
 ness of the star Algol a name derived from the Persian 
 word signifying the " demon." This star shines steadily 
 with a brightness equal to that of the Pole Star for nearly 
 two and a half days, and then suddenly its light is 
 reduced. In about four and a half hours the star's 
 
Photo, Lerv d Fits, Paris. 
 
 VIII. APOTHEOSIS OF THE SCIENCES. 
 Ceiling painting by Paul Albert Besnard (1849-...), 
 Salon des Sciences, Hotel de Ville, Paris. 
 
xii TOWARDS INFINITY 321 
 
 brightness is diminished by about two-thirds, and three 
 and a half hours later it has regained the former intensity, 
 which continues unaltered for another fifty-nine hours. 
 These variations succeed one another with clock-like 
 regularity, so that the times when the brightness of 
 Algol will fade can be tabulated years in advance, as 
 they are in the Nautical Almanack and similar publica- 
 tions. A navigator or other traveller with such a table 
 at hand can correct his watch by observing when the 
 star dims in brightness, and comparing the tabulated 
 time of this occurrence with the time shown by his 
 chronometer. 
 
 To explain the sudden reduction in light of Algol, 
 Goodricke suggested that a dark body is revolving 
 around the star, and periodically comes between us and 
 it, thus causing a partial eclipse in each revolution. 
 As a star can never be seen as anything but a point of 
 light, whatever telescopic means are employed, it is 
 impossible to distinguish any outlines of a dark body 
 upon a luminous disc, such as is seen, for instance, 
 during a partial eclipse of the sun by the moon, but 
 Goodricke's explanation was accepted, because it 
 accounted for the observed variations. The proof of the 
 hypothesis was not forthcoming for more than a century 
 after Goodricke suggested it ; and then it was reached 
 by indirect methods. Assuming that Algol has a dark 
 companion, the two bodies must swing round their 
 common balancing point, or centre of gravity. When the 
 dark body is moving towards us before passing in front 
 of the bright globe, the latter must be swinging back ; 
 and when the dark companion is receding after the 
 eclipse, the bright star must be approaching. Algol 
 must, therefore, alternately recede and approach in a 
 period which coincides with that of its changes of 
 G.D. x 
 
322 DISCOVERY CH. 
 
 brightness, if Goodricke's explanation of the cause of 
 variability is correct. 
 
 The spectroscope has proved that these periodic back 
 and forth movements of Algol do occur. By means of 
 this instrument, the velocity of approach or recession 
 of a star, with reference to the earth, can be determined 
 within a fraction of a mile a second ; and in the year 
 1888 Prof. H. C. Vogel, of the Potsdam Observatory, 
 showed that Algol recede , from the earth with a velocity 
 of about twenty-four miles a second before its light 
 dims, and approaches us at the rate of about twenty- 
 eight miles a second, after having been thus partially 
 eclipsed. Taking the average velocity as 26| miles a 
 second, the number of miles traversed around the 
 balancing point in the whole period can be easily 
 calculated, and thus the diameter of the orbit can be 
 obtained. Knowing these dimensions, and the period 
 of revolution, Kepler's third law (see p. 142) enables 
 the mass of Algol and its companion to be determined 
 in comparison with that of the sun. The conclusion 
 arrived at by this reasoning is that the dark companion 
 of Algol has about the same diameter as the sun, while 
 the star itself is somewhat larger. 
 
 The dark companion has never been seen, and probably 
 never will be, yet there is not the slightest doubt of its 
 existence among astronomers, nor can there be in any 
 mind that has considered the testimony given by the 
 spectroscope. About twenty stars are known to fluc- 
 tuate in light in the same manner as Algol, and each of 
 them is regarded as having a dark satellite which 
 periodically comes between us and the luminous 
 star. 
 
 The condition of things represented by Algol and 
 other stars of the same type must, however, be excep- 
 
xii TOWARDS INFINITY 323 
 
 tional. It happens that stars of this type have their 
 light partially obliterated by the interposition of dark 
 bodies between us and their luminous surfaces at regular 
 intervals ; but if these dead worlds passed a little above 
 or below the line of sight from the earth to the bright 
 star there would be no periodic eclipse, and, therefore, 
 no visible indication which would lead us to suspect the 
 existence of dark globes near the stars we see. Dark 
 stars may revolve around bright stars in orbits inclined 
 at any angle to the level in which the earth travels around 
 the sun, but only in those cases in which they are near 
 this level when they pass between us and their luminous 
 companions can a variation of light caused by them be 
 noticed. 
 
 It may seem, therefore, that the score or so stars 
 which are periodically dimmed by eclipse are the only 
 objects which are known to possess dark partners ; but 
 this is not the case. If two globes a bright one and a 
 dark one are really a united couple, each influences 
 the movements of the other, no matter what the direction 
 may be in which they revolve around their common 
 balancing point. The spectroscope shows that Algol is 
 swung back and forth by the invisible mass near it. By 
 what may almost be termed a fortunate accident, this 
 dark body passes in front of the bright star every three 
 days, and causes a sudden loss of light, but even if it 
 did not come directly between us and the luminous 
 surface the spectroscope would still detect a periodic 
 increase and decrease of pitch of the light rays. The 
 spectroscopic evidence of the movements of stars towards 
 the earth or away from it is, in fact, independent of 
 variations of light. If upon analysing determinations of 
 movements of approach or recession, it is found that a 
 star has its velocity increased and decreased in a definite 
 G.D. x 2 
 
324 DISCOVERY OH. 
 
 period, we are justified in concluding that there is an 
 invisible body in the neighbourhood swaying the bright 
 one round an orbit by the controlling influence of 
 gravitation. 
 
 A new field of study has thus been opened, and it 
 promises to add very greatly to our knowledge of the 
 universe. Measurements of the movements of stars 
 towards or away from the earth have been made for a 
 third of a century, but it is only in recent years that the 
 method employed has been brought to sufficient per- 
 fection to enable the observations to be made to a 
 high degree of accuracy. Now, however, that the rate 
 of approach or recession can be determined accurately, 
 the exact analysis of the motions has assumed a com- 
 pletely new aspect. Hitherto it has been of little 
 importance to know whether a star was increasing or 
 decreasing its distance from the earth, but now, by 
 examining the details of the movements, we find in 
 many cases secondary impulses backward or forward, 
 and these are unmistakable signs of bodies to be con- 
 sidered in addition to those of which we have ocular 
 proof. 
 
 The star Spica is an example of a bright body which 
 has a dark partner like that belonging to Algol, but does 
 not undergo a periodic loss of light by eclipse. Spectro- 
 scope observations show that the bright star alternately 
 swings towards the earth and away from it in a period of 
 four days, and they can be completely explained by 
 assuming that Spica has a companion that cannot be 
 seen, but is massive enough to make the visible star 
 move in an orbit. This attendant may be a dark globe 
 or a faint one so close to the star Spica that the most 
 perfect telescope available is powerless to show the two 
 bodies separately. But, whether lucid or obscure, the 
 
xii TOWARDS INFINITY 325 
 
 evidence of the spectroscope has shown that a star 
 which passed for a single body until a few years ago 
 has really a partner which insists upon making its 
 presence known. 
 
 The North Star Polaris also shows by its move- 
 ments that it is under the influence of one or more bodies 
 near it. In a period of about four days the star is found 
 to swing back and forth, doubtless as the result of 
 movement in an orbit. Moreover, there are indications 
 that Polaris and its satellite are in revolution together 
 around a third body, so that the system must be regarded 
 as a triple one. The movements of the moon and earth 
 with reference to the sun provides us with a similar 
 case, though on a much smaller scale ; for the moon 
 revolves around our globe once a month, while the earth 
 itself is traversing its annual path around the sun. 
 
 The few cases of dark stars already mentioned repre- 
 sent only the first fruits of the inquiry into the invisible 
 worlds in space. It is estimated that one star in every 
 three or four thus far investigated has near it a partner 
 which can never be seen. New methods of inquiry may 
 reveal many bodies beyond the power of the telescope 
 to show to human eyes, but even as the evidence stands 
 at present, we are assured of the existence of a vast 
 universe of invisible stars. The astronomy of the future 
 will be concerned as much with the study of these dark 
 masses as with those from which luminous radiations 
 are received. 
 
 The spectroscope has demonstrated the reality of dark 
 stars, but there are other means by which evidence of 
 the existence of invisible matter in space has been 
 obtained. The telescope and photographic camera have 
 shown that what seem to be blank regions of the sky in 
 many cases are crowded with sparkling points and realms 
 
326 DISCOVERY CH. 
 
 of celestial light of so refined a nature as to be impercep- 
 tible to unaided vision. Looking into the background of 
 infinity, the chemical retina of the photographic plate 
 may record nothing at first sight ; but let it remain with 
 steadfast gaze for an hour or so, and the accumulated 
 impressions produced by faint rays acting continuously 
 upon it will often show that there is indeed light in the 
 darkness of space. Stars and sheets of luminous material 
 have thus been depicted which no human eye has yet 
 been permitted to see directly. 
 
 It may be assumed that new worlds will continue to 
 be brought into light as new methods and new instru- 
 ments are used in the study of the heavens. There are 
 reasons for believing, however, that the thousand million 
 stars which can be seen with our largest telescopes, or 
 registered upon photographic films, represent practically 
 all that are shining in our universe. 
 
 Photographs of the streams and sheets of luminous 
 haze that exist in many parts of the heavens lead to the 
 conclusion that the starry universe visible from the 
 earth is limited in extent. Beyond a certain limit, long 
 exposures of sensitive plates to celestial light do not 
 reveal additional stars or nebulous realms ; and the 
 evidence suggests that, so far as number and extent are 
 concerned, the visible stellar universe has been completely 
 surveyed. 
 
 But though the stars can be numbered, no sounding- 
 line has yet been imagined which will fathom the depths 
 of infinite space. The human intellect may, in the course 
 of ages, comprehend the whole of our universe, but 
 infinity is beyond its grasp ; and in boundless space 
 there may be many universes like that around us. 
 Measured with our finite minds, the distances of the 
 stars are too great for us to have an adequate conception 
 
xii TOWARDS INFINITY 327 
 
 of them ; yet, immense as are these distances, there is 
 endless space beyond. The light which we now receive 
 from many of the faint stars has probably taken 
 hundreds of years to reach us, though it has travelled 
 through space at the rate of 186,000 miles per second. 
 There are ether stars so far away that their rays, which 
 touch the earth to-night, left them long before the 
 commencement of our era. May it not be possible, 
 therefore, that beyond the whole of this starry universe 
 which we know, there are unknown universes even 
 surpassing our own in glory, but the light of which has 
 not yet come to us ? 
 
 As to the existence of invisible universes beyond the 
 stars, we can only speculate ; but there is much dark 
 material within the boundary of our own universe, and 
 it has only been made manifest in recent years. " Evi- 
 dence of things unseen " has been and is being accumu- 
 lated, and we now know that there are in stellar space 
 vast clouds of cosmic dust, and many dark globes which 
 can never be seen or photographed. The parts of a 
 nebula visible to the eye or a camera are, in all 
 probability, only the luminous gases proceeding from 
 concentrated portions of a mass of dark particles 
 cosmic dust occupying a much greater region of 
 space. 
 
 What is seen or photographed is thus only a small 
 fraction of the whole bulk of a nebula. In the course 
 of aeons the irregular group of cosmic fragments is 
 whirled into shape, and as the mass contracts, portions 
 are detached which form stars, and these, in turn, are 
 the parents of worlds like the earth and other planets. 
 First, a congeries of cosmic dust ; then the faintly 
 luminous gleam of a nebula, arising from gases evolved 
 and illuminated by heat or electricity ; then a star in 
 
328 DISCOVERY CH. 
 
 which the heat is so intense that all known substances 
 are driven into vapour ; then a ball like the earth, with 
 a thin, solid crust covering a nucleus of rock hot enough 
 to be fluid ; and finally, a globe like the moon rolling 
 through space as a frozen world this apparently repre- 
 sents the course of evolution in the heavens. 
 
 But we only see these things " through a glass darkly "; 
 we grope in unfathomable space, and try to understand 
 the structure of a universe which may be only one 
 among many. Though a position may be gained from 
 which the whole of our universe may be grasped, there 
 will still be the boundary over which man cannot look to 
 see whether there are other universes beyond. Yet, with 
 unceasing desire for new knowledge, the man of science 
 pursues his ascent to exalted planes. Conscious that he 
 can know only in part, he still seeks to read the signs 
 and wonders of the heavens, and to find the inter- 
 pretation thereof. He takes the visible universe in 
 his mental grasp, and sees worlds in all stages of 
 growth, from formless mist to the finished star, which, 
 though fervidly shining now, must finally end and 
 be numbered among the dark and decaying systems 
 in space. 
 
 The human intellect can comprehend these things 
 because they have a beginning and an end, but imagina- 
 tion shrinks before the prospect of an infinite number of 
 universes, each perhaps more glorious than the one we 
 are permitted to explore. The heart that weeps and 
 trembles cannot face infinitude, which even in a vision 
 is awful in its majesty. In Jean Paul Richter's beautiful 
 dream, a man was called up into the vestibule of heaven 
 and carried to universe upon universe in endless space, 
 until his mind reeled before the transcendental distances 
 which were still before him. 
 
xii TOWARDS INFINITY 329 
 
 Then the man sighed and stopped, shuddered and wept. His 
 overladen heart uttered itself in tears, and he said, " Angel, I 
 will go no further ; for the spirit of man acheth with this infinity. 
 Insufferable is the Glory of God. Let me lie down in the grave 
 and hide me from the persecution of the Infinite, for end I see 
 there is none ..." Then the Angel lifted up his glorious 
 hands to the heaven of heavens, saying, " End is there none 
 to the universe of God. Lo ! also, is there no beginning ! " 
 
BIOGRAPHICAL INDEX 
 
 PAOK 
 
 A.FAUK 
 BBE, ERNST (1840-1905) 283 
 
 ADAMS, J. C. (1819-1892) 175 
 
 ADELARD OF BATH (Xllth Century) 128 
 
 AGASSIZ, Louis (1807-1873) - - - -6,43,56,78,103 
 ALRY, SIR GEORGE B. (1801-1892) - - - 272, 273, 284 
 
 ALHAZEN (Xlth Century) 127 
 
 ALLBUTT, SIR T. CLIFFORD (1836- . . .) - - . . 131 
 AMPERE, A. M. (1775-1836) - 238, 241, 242, 293 
 
 AMUNDSEN, ROALD (1872- . . .) 88 
 
 ANAXIMANDER (611-547 B.C.) 155 
 
 ARAGO, D. F. J. (1786-1853) - - 238 
 
 ARCHIMEDES (circa 287-212 B.C.) .... 69,261 
 ARISTARCHUS, OF SAMOS (circa 250 B.C.) - ... 144 
 ARISTOTLE (384-322 B.C.) 70, 92, 118, 132, 133, 137, 140, 143, 185 
 
 ARMSTRONG, H. E. 106 
 
 ARNOLD, MATTHEW (1822-1888) 198 
 
 AVEBURY, LORD (1834-1913) - 14 
 
 BACON, FRANCIS (1561-1626) - 96, 131, 133, 134, 135, 139, 311 
 
 BACON, ROGER (1214-1294) 128, 133 
 
 BAER, CARL ERNST VON (1792-1876) .... 53 
 
 BAIRSTOW, L. (1878- . . .) 291 
 
 BARTHOLOMEW, ANGLICUS (Xlllth Century) - - - 120 
 
 BATES, H. W. (1825-1892) 190 
 
 BATESON, W. (1861- . . .)- - , 192 
 
 BEACONSFIELD, EARL OF (1804-1881) .... 282 
 
 BEATTIE, JAMES (1735-1803) 92 
 
 BECQUEREL, A. H. (1852-1908) 306 
 
 BEECHER, H. WARD (1813-1887) 125 
 
 BEHRING, E. A. VON (1854- . . .) 236 
 
 BELL, A. GRAHAM (1847- . . .) 236 
 
BIOGRAPHICAL INDEX 331 
 
 PAGE 
 
 BERNARD, CLAUDE (1813-1878) 15 
 
 BERTHOLLET, C. L. (1748-1822) - - 41 
 
 BESSEL, F. W. (1784-1846) 83, 317, 318 
 
 BERZELIUS, J. J. (1779-1848) 246 
 
 BLACK, JOSEPH (1728-1799) - - - - - - 263 
 
 BLACKER, A. BARRY (1862-1902) - - -.. - 309 
 
 BONNET, C. (1720-1793) 72, 73, 74 
 
 BOUSSINGAULT, J. B. J. D. (1802-1887) 278 
 
 BOWERS, LIEUT. H. R. (1884-1912) 91 
 
 BOYLE, HON. ROBERT (1627-1691) - - 18, 267 
 
 BRADLEY, JAMES (1693-1762) 150, 151 
 
 BRAHE, TYCHO (1546-1601) - 134, 140, 141, 148, 150, 167, 168 
 
 BREWSTER, SIR DAVID (1781-1868) 143 
 
 BRONLAND, JORGEN (died 1907) - - - - 90 
 
 BROOKS, W. K. (1848-1908) - 234 
 
 BROWN, JOHN (1810-1882) - - - - - - 28 
 
 BROWN, ROBERT (1773-1858) ------ 81 
 
 BROWNE, SLR THOMAS (1605-1682) - - * - 50 
 
 BROWNING, ROBERT (1812-1889) - - - - - 31 
 
 BRUCE, SIR DAVID (1855- ...)- - - '* % . - 232 
 BRUCKNER, E. (1862- . . .) - - - -".-* - 96 
 
 BRUNO, GIORDANO (circa 1550-1600) - - - 146, 147 
 BRUNTON, SIR LAUDER (1844- ...) - - - - - 201 
 
 BRYAN, G. H. (1864- . . .) - 291 
 
 BUCKLAND, DEAN W. (1784-1856) - - - - - 113 
 
 BUFFON, COMTE DE (1707-1788) - --- 130, 186 
 
 BUMPAS, H. C. (1862- . . .) 189 
 
 BUNSEN, R. W. VON (1811-1899) - ... 247,256 
 BUTLER, CHARLES (1750-1832) 70 
 
 CABOT, JOHN (1450-1498) 85 
 
 CABOT, SEBASTIAN (1474-1557) 85 
 
 CAJORI, FLORIAN (1859- ...) 157 
 
 CALANDRUCCIO, S. - - - - - - - -118 
 
 CAMERARIUS, R. J. (1665-1721) 80 
 
 CARNOT, N. L. SADI (1796-1832) - - - - 180, 182 
 
 CAVENDISH, H. (1731-1810) 244, 246 
 
 CAYLEY, SIR GEORGE (1773-1857) - - - 285 
 
 CHANDLER, S. C. (1846-1914) 152 
 
 CHANUTE, OCTAVE (1832-1910) 286 
 
 CHAPMAN, S. (1888- . . .) 103 
 
332 BIOGRAPHICAL INDEX 
 
 PAGE 
 
 CHARLES II., KING (1630-1685) 137 
 
 CHATELIER, H. L. LE (1850- . . .) 248 
 
 CLAIRAUT, A. C. (1713-1765) - 6 
 
 CLERKE, Miss A. M. (1842-1907) - - - 84 
 
 CLIFFORD, W. K. (1845-1879) - ... 36 
 
 COLDING, L. A. (1815-1888) - - 180 
 
 COLUMBUS, CHRISTOPHER (1446-1506) - 85 
 
 CONFUCIUS (circa 550-478 B.C.) - 57 
 
 COOK, CAPT. JAMES (1728-1729) - - 86 
 
 COPE, E. D. (1840-1897) - - 196 
 
 COPERNICUS, NICOLAUS (1473-1543) 122, 130, 144, 146, 148, 167 
 COWPER, WILLIAM (1731-1800) 56 
 
 Cox, H. W. (1864-1910) - - 310 
 
 CROOKES, SIR WILLIAM (1832- . . .) 236, 239, 245, 296, 302, 304 
 CURIE, MADAME (1867- . . .) - - 235, 306 
 
 CURIE, P. (1859-1906) - - - 235, 306 
 
 CUVIER, G. L. C. F. D. (1769-1832) - 15 
 
 D ALTON, JOHN (1766-1844) - 162 
 
 DANTE, A. (1265-1321) - - 311 
 
 DARWIN, CHARLES R. (1809-1882) - 14, 16, 19, 25, 59, 
 75, 162, 163, 188, 189, 190, 192, 193, 195, 196 
 
 DARWIN, ERASMUS (1731-1802) - 186 
 
 DARWIN, SIR FRANCIS (1848- . . .) - 25 
 DAVY, SIR HUMPHRY (1778-1829) - 7, 8, 36, 162, 165, 179, 
 
 221, 234, 235, 253, 254, 259, 278 
 
 DEBIERNE, A. ... 306 
 
 DERBY, EARL OF, 16ra (1841-1908) - - 31 
 
 DESCARTES, RENE (1596-1650) - 179 
 
 DEVILLE, H. ST. CLAIRE (1818-1881) 10 
 
 DEWAR, SIR JAMES (1842- . . .) 252 
 
 DEWEY, JOHN (1859- . . .) - 36 
 
 DORPFELD, W. (1853- . . .) 85 
 
 DREYER, J. L. E. (1852- . . .) - 141 
 
 DUFOUR, J. M. LEON (1782-1865) - - 76 
 
 DUMAS, J. B. A. (1800-1884) - - 17, 126, 274 
 DURHAM, H. E. (1865- ...)-'- - - - - 229 
 
 DZIERZON, J. ( 181 1-1904) 71 
 
 EDISON, T. A. (1847- . . .) - - 236, 265, 266, 267 
 ELIOT, GEORGE (1819-1880) 23, 256 
 
BIOGRAPHICAL INDEX 333 
 
 PACK 
 
 ELLIS, W. (1828- . . .) 98 
 
 EMERSON, R. W. (1803-1882) 1, 234, 311 
 
 EMPEDOCLES (circa 490-430 B.C.) - - - - 177, 178 
 
 ERICKSEN, MYLIUS (died 1907) 89 
 
 EULER, LEONHARD (1707-1783) 152 
 
 EVANS, SIR JOHN (1823-1908) 115 
 
 EVELYN, JOHN (1620-1706) 94 
 
 FABRE, J. H. (1823-1915) 2, 75, 76 
 
 FALCONER, HUGH (1808-1865) 114 
 
 FARADAY, MICHAEL (1791-1867) - 3, 6, 12, 13, 36, 162, 235, 
 
 238, 242, 243, 253, 254, 293, 298 
 
 FISKE, JOHN (1842-1901) - - 27, 45 
 
 FORSYTH, A. R. (1858- . . .) - - - - - 234 
 
 FOSTER, SIR MICHAEL (1836-1907) - 36 
 
 FOUCAULT, J. B. L. (1819-1868) - - - - . - 159 
 FOURIER, J. B. J. (1768-1830) - 238, 242 
 
 FRANKLIN, BENJAMIN (1706-1790) - - - 156, 157, 158 
 
 FRANKLIN, SIR JOHN (1786-1847) 88 
 
 FRAUNHOJTER, J. VON (1787-1826) 236 
 
 FREDERICK THE GREAT (1712-1786) 23 
 
 FRESNEL, A. J. (1788-1827) - - 160, 238 
 
 GALEN (circa 130-200) - - - - - 137, 140 
 
 GALILEO (1564-1642) 2, 130, 132, 134, 137, 144, 145, 292, 316 
 GALLE, J. G. (1812-1910)- - - - 175 
 
 GALVANI, L. (1737-1798) - 184 
 
 GAMA, VASCO DA (1464-1524) - 85 
 
 GAUDRY, ALBERT (1827-1908) - - 196 
 
 GAUSS, K. F. (1777-1855) - 238, 241 
 
 GEIKIE, SIR ARCHIBALD (1835- . . .) - 116 
 
 GEORGE III., H.M. KING (1738-1820) - - - - 19, 47 
 GEORGE V., H.M. KING (1865- . . .) - - - - 282 
 
 GILBERT, WILLIAM (1540-1603) 131, 132, 134, 137 
 
 GLADSTONE, W. E. (1809-1898) - - - - 3, 14 
 
 GOD WIN- AUSTEN, H. H. (1834- . . .) - - 154 
 
 GOETHE, J. W. VON (1749-1832) - 23, 26, 92, 120, 186, 311 
 
 GOODRICKE, J. (1764-1786) 318, 319 
 
 GORGAS, COL. W. C. (1854- . . .) 230 
 
 GRANT, ROBERT E. (1793-1874) 68 
 
334 BIOGRAPHICAL INDEX 
 
 PAC1E 
 
 GBASSI, G. B. (1855- . . .) 118 
 
 GREELY, MAJOR-GEN. A. W. (1844- . . .) - - - - 89 
 
 GROSSETESTE, ROBERT (1175-1253) 128 
 
 GRYE, BOUQUET DE LA (1827-1909)- - 99 
 
 HADFIELD, SIR R. A. (1859- . . .) - 267 
 
 HAECKEL, E. H. (1834- . . .) - 196 
 
 HALLAM, HENRY (1777-1859) - - 130 
 
 HALLEY, E. (1656-1742) - - 9, 34, 169, 170, 172, 173, 174 
 HAMILTON, SIR WILLIAM R. (1805-1865) - - - - 284 
 HARCOURT, A. G. VERNON (1834- . . .) - - - 28 
 
 HARCOURT, CANON W. V. (1789-1871) - - 283 
 
 HARVEY, WILLIAM (1578-1657) - - 72, 137, 138 
 
 HELMHOLTZ, H. VON (1821-1894) - - - 180,295 
 
 HELPS, SIR ARTHUR (1813-1875) 36 
 
 HENRY, J. (1797-1878) - - - - 242, 293, 294 
 
 HENSON, W. S. (born 1805) - - 285 
 
 HERODOTUS (circa 490-420 B.C.) .... 79, 276 
 HERON, OF ALEXANDRIA (ITnd Century B.C.) - - - 261 
 HERSCHEL, SIR JOHN (1792-1871) 36, 54, 98, 166, 175, 284, 317 
 HERSCHEL, SIR WILLIAM (1736-1822) 19, 47, 59, 62, 63, 175, 317 
 HERTZ, H. R. (1857-1894) - 235, 236, 295, 296, 297, 298, 302 
 HILAIRE, ETIENNE GEOFFROY ST. (1772-1844) - - 196 
 
 HIPPARCHUS (190-120 B.C.) 69 
 
 HIPPOCRATES (Vth Century B.C.) ... - 140, 201 
 HOFMANN, A. W. VON (1818-1892) - - - 162, 251 
 
 HOLMES, OLIVER WENDELL (1809-1894) - 221 
 
 HOOKE, ROBERT (1635-1703) 169 
 
 HOOKER, SIR JOSEPH (1817-1911) - - 192 
 
 HOPKINS, CYRIL G. (1866- . . .) 279 
 
 HUBER, F. (1750-1831) - ... 71 
 
 HUGGINS, SIR WILLIAM (1824-1910) - - - 32, 238, 285 
 
 HUMBOLDT, BARON VON (1769-1859) - 129 
 
 HUME, DAVID (1711-1776) - - 40 
 
 HUNTER, JOHN (1728-1793) - -* - - 139,140,207 
 HUXLEY, T. H. (1825-1895) - 10, 13, 16, 23, 27, 36, 39, 45, 
 
 92, 125, 165, 196, 199, 255 
 HUYGENS, CHRISTIAN (1629-1695) - - - 159 
 
 JACKSON, F. G. (1860- . . .) 87 
 
 JACKSON, H. (1864- . . .) 304 
 
BIOGRAPHICAL INDEX 335 
 
 PA OK 
 
 JACOBT, C. G. J. (1804-1857) 5 
 
 JANSSEN, P. J. C. (1824-1907) 66 
 
 JENNER, EDWARD (1749-1823) - - 139, 206, 207, 208, 209 
 
 JOHNSON, DR. SAMUEL (1709-1784) 33 
 
 JOHNSON, REV. S. J. (1845-1905) 98 
 
 JOULE, J. P. (1818-1889) - - - - 180,181,182,185 
 JUVENAL, D. J. J. (circa 60-140) 1 
 
 KEATS, JOHN (1795-1821) - - 42 
 
 KEKULE, F. A. (1829-1896) 249 
 
 KELVIN, LORD (1824-1907) - - 20, 24, 52, 56, 58, 60, 181, 
 182, 242, 260, 268, 269, 270, 271, 273, 291, 295 
 KENNEDY, ADMIRAL SIR W. R. (1838- . . .) - - - 270 
 KEPLER, JOHANN (1571-1630) - 130, 134, 141, 142, 167, 168, 322 
 KINGSLEY, CHARLES (1819-1875) - - 23, 43, 47, 49, 92 
 
 KIRCHHOFF, G. (1824-1887) 236 
 
 KITASATO, S. (1856- . . .) 224, 236 
 
 KLAPROTH, M. H. (1743-1817) 246 
 
 KOCH, ROBERT (1843-1910) ...... 210 
 
 KUSTNER, F. (1856- . ,.) 152 
 
 LAGRANGE, J. L. (1736-1813) - - 291 
 
 LALANDE, J. J. L. DE (1732-1807) 6, 47 
 
 LAMARCK, JEAN DE (1774-1829) - - - 165, 187, 188 
 
 LANCHESTER, F. W. (1868- . . .) 291 
 
 LANGLEY, S. P. (1834-1906) 235, 287, 288, 289, 290 
 
 LANKESTER, SIR RAY (1847- . . .) 198 
 
 LAPLACE, MARQUIS DE (1749-1827) 165 
 
 LAVAL, G. DE 261 
 
 LAVERAN, P. L. A. (1845- . . .) 226 
 
 LAVOISIER, A. L. (1743-1794) - - - - - 239, 240 
 
 LAWES, SIR J. B. (1814-1900) 281 
 
 LAZEAR, DR. J. W. (died 1900) 228, 232 
 
 LECKY, W. E. H. (1838-1903) 3 
 
 LEEUWENHOEK, A. VAN (1632-1723) 73, 138 
 
 LEIBNITZ, G. W. (1646-1716) 19 
 
 LEIDY, JOSEPH (1823-1891) 17 
 
 LENARD, P. (1862- . . .) 236, 302 
 
 LEONARDO DA VINCI (1452-1519) - - 77, 129, 130, 134 
 LESSEPS, FERDINAND DE (1805-1894) 230 
 
 LESSING, G. E. (1729-1781) 23 
 
336 BIOGRAPHICAL INDEX 
 
 PAfll 
 
 LEVERRIER, U. J. J. (1811-1877) 175 
 
 LIEBIG, BARON VON (1803-1873) - - - 235, 279 
 
 LILIENTHAL, OTTO (1849-189(5) - - 286 
 
 LINNAEUS, CARL (1708- 1778) 119 
 
 LISTER, LORD (1827-1912) - - 200, 213, 217, 218, 219 
 
 LOCKYER, SIR NORMAN (1836- . . .) - 61, 62, 236 
 
 LODGE, SIR OLIVER (1851- ...) - 295 
 
 LOEFFLER, F. ( 1 852- ...')- 21 6 
 
 LOMMEL, E. VON (1837-1899) - - 184 
 
 LONG, C. W. - - - 222 
 
 LONGFELLOW, H. W. (1807-1882) - 44, 165 
 
 Louis PHILIPPE (1773-1850) 15 
 
 LOWELL, J. R. (1819-1891) - 23, 256 
 
 LYELL, SIB CHARLES (1797-1875) - 192 
 
 MACAULAY, LORD (1800-1859) 56, 206 
 MACMILLAN, ALEXANDER (1818-1896) .... 45 
 
 MAETERLINCK, MAURICE (1862- . . .) 75 
 
 MAGELLAN, FERDINAND (1470-1521) 85 
 
 MALPIGHI, MARCELLO (1628-1694) - 138 
 
 MALTHUS, T. R. (1766-1834) - - 188, 191 
 
 MARCONI, G. (1874- . . .) - 236, 297, 298, 301 
 
 MARCUS AURELIUS (121-180) - - 125,256 
 
 MAREY, E. J. (died 1904) 266 
 
 MATHER, SIR WILLIAM (1838- ...) - - - - 125 
 
 MAXIM, SIR HIRAM (1840- . . .) 286 
 
 MAX-MULLER, F. (1823-1900) - 1 
 
 MAXWELL, J. CLERK (1831-1879) - 235, 293, 294, 295, 298 
 
 MAYER, J. R. (1814-1878) 180 
 
 MELDOLA, RAPHAEL (1849-1915) 40 
 
 MENDEL, G. J. (1822-1884) - 192, 193, 194, 195 
 MIALL, L. C. (1842- . . .) - - 58, 69, 71, 74, 80, 117, 120, 135 
 
 MICHELSON, A. A. (1852- . . .) - - - - - 66 
 
 MlKKELSEN, ElNAR (1880- . . .) 90 
 
 MILTON, JOHN (1608-1674) - 70,156 
 
 MINOT, C. S. (1852-1914)- - 239 
 
 MITCHELL, S. WEIR (1830-1914) ... 17 
 
 MOHR, K. F. (1806-1879)- - 180 
 
 MOISSAN, H. (1852-1907)- - - 248 
 
 MOORE, SIR JOHN (1845- ...) - - - - - - 95 
 
 MORTON, W. T. G. (1819-1868) 222 
 
BIOGRAPHICAL INDEX 
 
 MUYBRIDGE, E. (1820-1904) ^ 
 
 MYERS, F. W. H. (1843-1901) 
 
 MYERS, WALTER (1872-1901) 
 
 NANSEN, FRIDTJOF (1861- . . .) 86 
 
 NAPOLEON I. (1769-1821) 209 
 
 NAPOLEON III. (1808-1873) 6,15 
 
 NEWCOMB, SIMON (1835-1909) 5, 153, 313 
 
 NEWCOMEN, T. (1663-1729) - - - 261, 262, 263, 264 
 NEWTON, SIR ISAAC (1642-1727) - 9, 19, 67, 134, 154, 155, 
 
 158, 162, 169, 170, 171, 172, 173, 174, 182, 185, 
 
 236, 287, 316. 
 
 NICHOLS, E. L. (1854- . . .) 103 
 
 NIPHER, F. E. (1847- . . .) 238 
 
 GATES, CAPT. L. E. G. (1880-1912) - - - - - 90 
 
 OERSTED, H. C. (1777-1851) 50,241,242 
 
 OHM, G. S. (1787-1854) 183, 184, 185 
 
 OKU, GENERAL (1845- . . .) - 204 
 
 OLBERS, H. W. M. (1758-1840) ..... 83 
 ORESME, BISHOP OF LISIEUX (died 1382) - - - - 143 
 OSBORN, H. F. (1857- . . .) 43 
 
 PAGET, SIR JAMES (1814-1899) 275 
 
 PALISSY, BERNARD (1510-1589) 77, 130, 132, 134 
 
 PAPIN, D. (1647-1712) 262 
 
 PARKHURST, C. H. (1842- . . .) 256 
 
 PARSONS, HON. SIR C. A. (1854- . . .) - - - - 261 
 
 PASTEUR, Louis (1822-1895) - - 6, 10, 11, 206, 210, 211, 
 
 212, 213, 214, 215, 217, 220, 235, 274, 275 
 
 PEARY, REAR-ADMIRAL R. E. (1856- . . .) - - - 87, 89 
 
 PEIRCE, C. S. (1839- . . .)- - 24 
 
 PENAUD, ALPHONSE (1850-1880) 285 
 
 PEPYS, SAMUEL (1633-1703) - .... 94, 137 
 PEREGRINUS, PETER (XHIth Century) - - - 128, 131 
 
 PERKIN, SIR W. H. (1838-1907) 250 
 
 PERTHES, BOUCHER DE (1788-1868) 114 
 
 PHILLPOTTS, EDEN (1862- ...) 1 
 
 PICARD, J. (1620-1682) 171 
 
 PICKERING, E. C. (1846- ...) 65,149 
 
 PICKERING, W. H. (1858- . . .) 101 
 
338 BIOGRAPHICAL INDEX 
 
 PAGE 
 
 PILCHEB, PERCY S. (1866-1899) 286 
 
 PLATO (circa 427-347 B.C.) 166 
 
 PLAYFAIR, LORD (1818-1898) 14 
 
 PLINY, THE ELDER (circa 23-79) 276 
 
 PLUTARCH (circa 46-120) Ill 
 
 POINCARE, HENRI (1854-1912) 170 
 
 POISSON, S. D. (1781-1840) - 237 
 
 POPE, ALEX. (1688-1744)- - - 20 
 
 PRESTWICH, SIR JOSEPH (1812-1896) 81, 114 
 
 PRIESTLEY, J. (1733-1804) - 244, 246, 251 
 
 PTOLEMY, CLAUDIUS (Ilnd Century A.D.) - - - 127, 143 
 PYTHAGORAS (566-470 B.C.) - - - -69,127,143 
 
 RAMSAY, SIR ANDREW (1814-1891) - - - - - 78 
 RAMSAY, SIR WILLIAM (1852- . . .) - - 60, 61, 62, 308 
 
 RALEIGH, SIR WALTER (1552-1618) - - 186 
 
 RAYLEIGH, LORD (1842- . . .) 60, 62 
 
 REAUMUR, R. A. F. DE (1683-1757) - 69, 71, 73, 75, 119, 244 
 REED, WALTER (1857-1903) - - - 228 
 
 REMSEN, IRA (1846- ...)-- 253 
 
 RICHTER, J. P. F. (1763-1825)- - - 328 
 
 RIGOLLOT, DR. - 114 
 
 RONTGEN, C. W. (1856- . . .) - 236, 301, 303, 304, 305, 306, 309 
 ROSCOE, SIR HENRY (1833-1915) - ... 182, 247 
 Ross, SIR RONALD (1857- . . .) - - - 226, 227, 228, 233 
 ROUTH, E. J. (1831-1907) - - 291 
 
 Roux, P. P. E. (1853- . . .) - - 8, 216, 235 
 
 ROWLAND, H. A. (1848-1901) - - - 27 
 
 RUMFORD, COUNT (1753-1814) - - - - - - 179 
 
 RUSKIN, JOHN (1819-1900) - 92 
 
 RUTHERFORD, SIR E. (1871- . . .) v - - - 306, 307 
 RYLE, RIGHT REV. BISHOP (1856- . . .) - - - - 23 
 
 SACKEN, BARON OSTEN (1828-1906) 120 
 
 SAGE, C. LE (1724- ...) - - - - . - 176 
 
 SANTOS-DUMONT, A. (1873- . . .) 290 
 
 SAUSSURE, N. T. DE (1767-1845) -. .- - - - 278 
 
 SAVERY, T. (1650-1715) - - - - - - 2G1 
 
 SCHAEBERLE, J. M. (1853- . . .) - - - 318 
 
 SCHEELE, K. W. (1742-1786) 251 
 
 SCHIRACH, A. G. (1724-1773) 71 
 
BIOGRAPHICAL INDEX 339 
 
 PAGK 
 
 SCHLIEMANN, H. (1822-1890) ------ 84 
 
 SCHMIDT, G. K. (1865- ...) 306 
 
 SCHOTT, OTTO (1851- ...) 283 
 
 SCHROTER, J. H. (1745-1816) 84 
 
 SCHWABE, S. H. (1789-1875) 63 
 
 SCOTT, CAPT. R. F. (1868-1912) 90 
 
 SEDGWICK, ADAM (1785-1873) 163 
 
 SENECA (circa 3 B.C.-65 A.D.) - - - - - 56, 293 
 
 SENIER, A. (1853- . . .) 162,249 
 
 SHAKESPEARE, WILLIAM (1564-1616) 1, 26, 70, 123, 178 
 
 SIMPSON, SIR J. Y. (1811-1870) .... 221,222 
 
 SMITH, ARCHIBALD (1813-1872) 272 
 
 SMITH, EDGAR F. (1856- ...) - - '- - - - 17 
 
 SMITH, WILLIAM (1769-1839) 77, 197 
 
 SODDY, F. (1877- . . .) 292, 307 
 
 SOUBEIRAN, E. (1757-1858) 235 
 
 SPENCER, HERBERT (1820-1903) - - - - - 41, 51 
 
 STARLING, E. H. (1866- . . .) 201 
 
 STEPHENSON, GEORGE (1781-1848) - 258, 259 
 
 STRINGFELLOW, J. (1799-1883)- - - 285 
 
 SUTTON, J. R. 99 
 
 SWAMMERDAM, J. J. (1637-1680) - - 71, 72, 73, 119 
 SWIFT, JONATHAN (1667-1745) 281 
 
 TAYLOR, JEREMY (1613-1667) 56 
 
 TELESIO, BERNARDINO (1509-1588) 129 
 
 TENNYSON, ALFRED, LORD (1809-1892) - - - - 30, 55 
 THALES, OF MILETUS (circa 640-548 B.C.) - 21, 143 
 
 THISELTON-DYER, SIR W. (1843- .'..) - - - "- 200 
 
 THOMPSON, FRANCIS (1860-1907) 46 
 
 THOMPSON, SILVANUS P. (1851- . . .) - - - - 292 
 
 THOMSON, J. ARTHUR (1861- . . .) 1, 201 
 
 THOMSON, SIR J. J. (1856- . . .) 21, 306 
 
 THOMSON, W. See LORD KELVIN. 
 
 THORPE, SIR T. E. (1 845-. ..)- - - - - - 240 
 
 TILDEN, SIR WILLIAM (1 842-. ..) 237 
 
 TULLOCH, LIEUTENANT (died 1906) 232 
 
 TYNDALL, JOHN (1820-1893) - - - - 6, 7, 162, 243 
 
 VALERIUS CORDUS (1515-1544) 235 
 
 VERGJL (70-19 B.C.) 119 
 
340 BIOGRAPHICAL INDEX 
 
 PAGE 
 
 VICTORIA, QUEEN (1819-1901) 224 
 
 VIRCHOW, RUDOLF (1821-1902) - - - 52 
 
 VOGEL, H. C. (1842- ...)-- - 322 
 
 VOLNEY, COUNT DE (1757-1820) ..... 51 
 
 WALLACE, A. R. (1823-1914) - 18, 188, 190, 191, 192 
 
 WARD, R. DE C. (1867- ...)-- 97 
 
 WATSON, W. (1858- ...)- - , - - - - 311 
 
 WATT, JAMES (1736-1819) 260, 262, 263, 264, 265 
 
 WATTS, G. F. (1817-1904) 51 
 
 WEBER, W. E. (1804-1891) - ' , ' - 241 
 
 WELLS, HORACE (1815-1848) .... - - 222 
 
 WELLS, H. G. (1866- . . .) 164, 266 
 
 WELSH ACH, AUER VON (1858- . . .) - 246 
 
 WHITEHEAD, A. N. (1861- . . .) - 234 
 
 WHITNEY, W. R. (1868- . . .) - - 244 
 
 WILKINS, MARY E. - - 165 
 
 WILLSON, T. L. (died 1915) - - 248 
 
 WILSON, E. A. (1873-1912) - 91 
 
 WILSON, GEORGE (1818-1859) - 220 
 
 WOHLER, F. (1800-1882) - - - 248, 249 
 
 WOLLASTON, W. H. (1766-1828) 64, 236 
 
 WREN, SIR CHRISTOPHER (1632-1723) - 169 
 
 WRIGHT, SIR ALMROTH (1861- . . .) - 205 
 
 WRIGHT, ORVILLE (1871- . . .) - - 289, 290 
 
 WRIGHT, WILBUR (1867-1912) - - 289, 290 
 
 XENOPHANES (Vlth Century B.C.) - -- '- - - 51 
 
 YERSIN, DR. (1863- . . .) - ... 224, 235 
 
 YOUNG, THOMAS (1773-1829) - - - - 159, 160 
 
 ZEISS, CARL (1818-1888) 283 
 
 GLASGOW : PRINTED AT THE UNIVERSITY PRESS BY ROBERT MACLEHOSK AND CO. LTD. 
 
UNIVERSITY OF CALIFORNIA LIBRARY 
 BERKELEY 
 
 Return to desk from which borrowed. 
 This book is DUE on the last date stamped below. 
 
 JAN 9 1953 LO 
 
 OCT7 
 
 17Mar'?9JT 
 REC'D LD 
 
 MARS 1959 
 
 23Jul'60TD 
 
 LD 21-100m-7,'52(A2528sl6)476 
 
 JUL9 60 
 171981 
 
 ES UK. JUL 2 9 
 
 mi 
 
YB 56824 
 
 . 
 
 UNIVERSITY OF CALIFORNIA LIBRARY