GIFT OF 
 
BRITAIN'S HERITAGE OF SCIENCE 
 
Sir Isaac Newton 
 
 From an engraving of a 
 painting by Kneller, in the 
 Possession of Lord Portsmouth 
 
BRITAIN'S HERITAGE 
 OF SCIENCE 
 
 BY 
 
 ARTHUR SCHUSTER, F.R.S. 
 
 AND 
 
 ARTHUR E. SHIPLEY, F.R.S. 
 ILLUSTRATED 
 
 LONDON 
 
 CONSTABLE & CO. LTD. 
 1917 
 
..*: 
 
 ' - : ' v 
 
 m 
 
ERRATA. 
 
 Page 70, line 5 from bottom : 
 
 far "Robert" read "Charles." 
 
 Page 286, line 10 from bottom : 
 
 for "Sir William Herschel " read "Sir William 
 James Herschel, eldest son of Sir John 
 Herschel." 
 
 for " Foulds " read " Faulds." 
 
 Page 291 , line 11 from top : 
 
 for " Thompson " read " Thomson." 
 
LIST OF PORTRAITS 
 
 SIR ISAAC NEWTON - Frontispiece 
 
 From an engraving of a painting by Kneller, in the posses- 
 sion of Lord Portsmouth. 
 
 JOHN DALTON - Facing p. 16 
 
 From a painting by R. R. Faulkner, in the possession of the 
 Royal Society. 
 
 MICHAEL FARADAY - Facing p. 32 
 
 From a painting by A. Blakeley, in the possession of the 
 Royal Society. 
 
 THE HON. ROBERT BOYLE - - Facing p. 72 
 
 From a painting by F. Kerseboom, in the possession of the 
 Royal Society. 
 
 JOHN CLERK MAXWELL - Facing p. 86 
 
 From an engraving in " Nature " by G. J. Stodart of a photo- 
 graph by Fergus, of Glasgow. 
 
 SIR HUMPHRY DAVY - - Facing p. 112 
 
 From a painting by Sir Thomas Lawrence, in the possession 
 of the Royal Society. 
 
 SIR GEORGE GABRIEL STOKES - - Facing p. 124 
 
 From a photograph by Fradelle & Young. 
 
 370907 
 
vi List of Portraits 
 
 JAMES PEESCOTT JOULE - Facing p. 160 
 
 From a photograph by Lady Roscoe. 
 
 WILLIAM THOMSON, LORD KELVIN - Facing p. 190 
 
 From a photograph by Messrs. Dickinsons. 
 
 THOMAS YOUNG - - Facing p. 212 
 
 From a portrait by Sir Thomas Lawrence. 
 
 JOHN RAY - - Facing p. 232 
 
 After a portrait in the British Museum. 
 
 STEPHEN HALES - - Facing p. 236 
 
 After a portrait by Thomas Hudson. 
 
 CHARLES DARWIN - Facing p. 268 
 
 After a photograph by Messrs. Maidl & Fox. 
 
 WILLIAM HARVEY - Facing p. 294 
 
 After a painting by Cornelius Janssen, now at the College of 
 Physicians. 
 
 CHARLES LYELL - - Facing p. 310 
 
 After a daguerreotype by J. E. Mayal. 
 
SYNOPSIS OF CONTENTS 
 
 CHAPTER PAGES 
 
 I. THE TEN LANDMARKS OF PHYSICAL SCIENCE 1-45 
 
 Roger Bacon Gilbert, the founder of terrestrial mag- 
 netism, his electrical researches Napier's discovery of 
 logarithms Continuity of scientific progress in Great 
 Britain from the seventeenth century onwards New- 
 ton's laws of motion and discovery of gravitation 
 Importance of Newton's work Foundation of modern 
 chemistry by Dalton Foundation of undulatory theory 
 of light by Young Faraday's electrical discoveries 
 Conservation of energy established by Joule and Thom- 
 son Clerk Maxwell's electro -magnetic theory of light 
 His work on kinetic theory of gases Biographical 
 notes on Newton, Dalton, Young, Faraday, Joule, 
 Thomson, and Clerk Maxwell. 
 
 II. PHYSICAL SCIENCE THE HERITAGE OF THE 
 UNIVERSITIES DURING THE SEVENTEENTH AND 
 EIGHTEENTH CENTURIES - - 46-71 
 
 Activity in the Universities during the seventeenth cen- 
 tury Foundation and early history of Gresham College 
 Briggs, tables of logarithms and decimal fractions 
 Edward Wright and Mercator's projection Wallis 
 Lord Brouncker's use of infinite series Wren's mathe- 
 matical and astronomical work The Gregory family, 
 first suggestion of reflecting telescopes Newton's op- 
 tical discoveries Robert Hooke, " Micrographia " 
 Flamsteed, first Astronomer Royal Halley's mag- 
 netical and astronomical work Bradley's discovery of 
 aberration and nutation Bliss Maskelyne, founder 
 of the "Nautical Almanac" Density of earth The 
 Scottish Universities William Cullen, founder of the 
 Scottish school of Chemistry Black's chemical dis- 
 coveries Latent heat Use of hydrogen for filling 
 balloons Rutherford's isolation of nitrogen Robison 
 Playfair Desaguliers Robert Smith. 
 
viii Contents 
 
 CHAPTER PAGES 
 
 III. PHYSICAL SCIENCE THE NON-ACADEMIC HERIT- 
 AGE DURING THE SEVENTEENTH AND EIGHTEENTH 
 
 CENTURIES - 72-105 
 
 Distinction between amateurs and professional men 
 of science Robert Boyle's life and work Boyle's law 
 Optical and chemical experiments Taylor's theorem 
 Early history of the Royal Society First record 
 of electric spark by Hauksbee Isolation of argon 
 forestalled Joseph Priestley, chemical production 
 of oxygen Composition of water Direct proof of 
 gravitational attraction by Cavendish Michell's tor- 
 sion balance Horrocks, first observation of transit 
 of Venus Molyneux William Herschel, discovery 
 of Uranus and other astronomical work Discovery of 
 infra-red radiations Importance of construction of 
 scientific instruments Oughtred's slide-rule Gas- 
 coigne's eyepiece -micrometer Hadley's sextant Tem- 
 perature compensation of pendulum by Graham and 
 Harrison Divided circles Ramsden's eyepiece 
 Achromatism : More Hall and Dollond Early history 
 of steam engine : Somerset, Savery, Papin, Newcomen 
 Improvements by James Watt Invention of con- 
 denser First locomotive constructed by Trevithick 
 First compound engine by Hornblower Murdock and 
 illuminating gas Bramah's hydraulic press. 
 
 IV. PHYSICAL SCIENCE THE HERITAGE OF THE 
 
 NINETEENTH CENTURY - - 106-142 
 
 Nicholson's electrolytic decomposition of water Cor- 
 relation of physical forces Count Rumford's generation 
 of heat by mechanical power Humphry Davy Dis- 
 covery of laughing gas Isolation of metallic potassium 
 and sodium Safety lamp Revival of scientific re- 
 search at Cambridge Woodhouse, Peacock, Whewell 
 Physical optics advanced by Airy and Baden Powell 
 The golden age of mathematical physics at Cambridge 
 Green Stokes' researches on light and hydrodynamics 
 Fluorescence Discovery of Neptune by Adams 
 Sylvester, Cayley, Routh Miller's work on crystallo- 
 graphy Physical science in the Scottish Universities 
 Maximum density of water discovered by Hope 
 Leslie's investigations on radiant heat Brewster's 
 researches on light Important work of Forbes Tait, 
 Chrystal, Kelland Rankine and conservation of energy 
 James Thomson Hamilton, discovery of conical 
 refraction Physical science in Ireland Trinity College 
 
Contents ix 
 
 CHAPTER PAGES 
 
 Lloyd, McCullagh, Jellett, Salmon, Haughton Fitz- 
 gerald, Johnstone Stoney Andrews on ozone and 
 liquefaction of gases Science at Oxford : Henry Smith, 
 Odling, Vernon Harcourt, Pritchard. 
 
 V, PHYSICAL SCIENCE THE HERITAGE OF THE 
 
 NINETEENTH CENTURY (continued)- - 143-186 
 
 Foundation of University of London University Col 
 lege and King's College De Morgan Graham's re- 
 searches on gases Discovery of palladium and rhodium 
 by Wollaston Chemical work of Williamson Electrical 
 researches of Wheatstone Owens College and Man- 
 chester University Chemical school of Frankland and 
 Roscoe Osborne Reynolds and scientific engineering 
 Balfour Stewart on radiation and absorption History 
 of spectrum analysis Discovery of thallium by Crookes 
 Riicker's researches on thin films, his magnetic sur- 
 veys Poynting and energy paths Radiation pressure 
 Distinguished work of amateurs : Baily, Gassiot, 
 Grove, Spottiswoode, Schunck, Sorby Waterston's 
 neglected investigations on theory of gases Progress in 
 astronomy : John Herschel, Gill, Rosse, Lassell, Nas- 
 myth Application of photography to astronomy : de 
 la Rue, Common, Roberts Application of spectrum 
 analysis to astronomy : Lockyer, Huggins Newall's 
 large telescope Early history of photography : Wol- 
 laston, Wedgwood, Herschel, Fox Talbot Dry plates 
 and gelatine emulsions Abney's work on theory of 
 photography Colour photography : Rayleigh, Joly 
 Geophysical work of Kater, Sabine, Clarke Meteoro- 
 logical work of Wells, Howard, Apjohn, Glaisher, 
 Archibald, Buchan, Aitken George Darwin and cos- 
 mical evolution Foundation of seismology by Milne 
 Recent advances in physics Rayleigh's discovery of 
 argon Researches of Ramsay Discovery of helium 
 Crookes' radiometer His improvement of air pumps 
 J. J. Thomson and electric discharge through gases 
 Electric constitution of matter Larmor Discovery of 
 radio-activity Rutherford's discovery of emanation 
 Theory of radio-activity Moseley's brilliant researches 
 and early death. 
 
 VI. PHYSICAL SCIENCE SOME INDUSTRIAL APPLI- 
 CATIONS - - - - 187-202 
 
 Manufacture of steel The electric telegraph : Ronalds, 
 Cooke, Wheatstone Submarine cables : Kelvin, Newall, 
 Hancock Vulcanization of rubber The microphone 
 
x Contents 
 
 CHAPTER PAGES 
 
 of Hughes Sturgeon's electromagnet Development of 
 electrical industry Wilde Hopkinson, Ewing, Ayrton 
 The alkali industry : Gamble, Leblanc, Muspratt, 
 Gossage, Solvay, Mond, Deacon, Weldon Royal Col- 
 lege of Chemistry Discovery of coal-tar dyes Perkin, 
 Nicholson Early promise and subsequent neglect of 
 industry Meldola Explosives : Abel, Dewar Play- 
 fair and encouragement of science. 
 
 VII. PHYSICAL SCIENCE SCIENTIFIC INSTITUTIONS 203-215 
 
 Early history of Royal Society Privileges as regards 
 patents Their action in promoting food production, 
 inoculation, the prevention of jail fever, and protection 
 against lightning Repository of natural rarities Pro- 
 motion of scientific expeditions, surveys Comparison 
 of standards Connexion with Greenwich Observatory 
 and Meteorological Office Foundation of National 
 Physical Laboratory Friendly relations with foreign 
 academies Royal Society of Dublin Royal Society 
 of Edinburgh Royal Society of Arts and other scientific 
 societies Constitution of Royal Society compared with 
 that of foreign academies Royal Institution Dewar's 
 work on liquefaction of gases The British Association. 
 
 VIII. BIOLOGICAL SCIENCE IN THE MIDDLE AGES- 216-228 
 
 Physiologus Bartholomew's " Liber de Proprietatibus 
 Rerum " Roger Bacon yesalius, the founder of 
 modern anatomy and physiology Moffett Biological 
 science in Elizabethan and Stewart times Francis 
 Bacon Lord Herbert Evelyn Pepys King Charles' 
 interest in science. 
 
 IX. BOTANY - - 229-255 
 
 Early herbalists Turner, Gerard, Johnson New era 
 inaugurated by Ray Morison Grew, one of the 
 first students of vegetable anatomy Hales, the 
 founder of the physiology of plants Knight and cir- 
 culation of sap Foundation of Linnsean Society by 
 Smith Scientific explorers : Sloane, Banks Great 
 Britain leads the way in introducing scientific classifica- 
 tion Robert Brown Discovery of nucleus of cells 
 Brownian movement Lindley, a great taxonomist 
 The elder Hooker, Bentham -Joseph Hooker; early 
 expeditions, friendship with Darwin, Himalayan 
 travels Flora Indica Huxley's influence on teaching 
 of botany Berkeley and cryptogamic botany Botany 
 
Contents xi 
 
 CHAPTER PAGES 
 
 at Oxford : Sherard, Sibthorp, Daubeny Botany at 
 Cambridge : Martyn, Henslow, Marshall Ward Botany 
 in Scotland : Sutherland, Greville, Balfour Botany in 
 Ireland : Threlkeld, Allman Historical summary of 
 British Botany. 
 
 X. ZOOLOGY - - 256-293 
 
 Early history Turner, Wotton, Caius, Topsell 
 Influence of falconry Willughby and Ray The Tra- 
 descants Zoology in eighteenth century : Pennant, 
 William Hunter -John Hunter, his zoological collections 
 Revival in nineteenth century Owen His efforts 
 to reorganize the natural history department of British 
 Museum Charles Darwin His ancestry, Erasmus Dar- 
 win Studies at Edinburgh and Cambridge Voyage 
 of the "Beagle" Appreciation of Darwin's work by 
 Wallace History of evolution and natural selection 
 Heredity Early supporters of Darwin : Huxley, Lyell, 
 Hooker The work of Wallace Allman Huxley, 
 morphologist, teacher, and organizer F. M. Balfour's 
 work on embryology and early death Romanes, Sedg- 
 wick Biometrics : Weldon, Galton Ray Lankester, 
 his work on morphology and other branches of zoology 
 Maritime zoology Edward Forbes, Gosse Voyage 
 of " Challenger " Scientific results of cable laying 
 Progress in scientific classification during nineteenth 
 century Exploration of Central America by Godman 
 and Salvin Marine stations and laboratories. 
 
 XI. PHYSIOLOGY - 294-307 
 
 Harvey, the circulation of blood Mayow's researches 
 on respiration and the oxidizing of venous blood, 
 muscular heat Medical science and physiology Syden- 
 ham, Glisson, Lower and the transfusion of blood 
 Willis and brain anatomy Havers' " Osteologia Nova " 
 Important researches of Hales, blood pressure, secre- 
 tions Joseph Black's contributions to physiology 
 Hewson, discovery of lymphatic and lacteal vessels 
 Coagulation Young, founder of physiological optics 
 Addison Bowman Cambridge School of Physio- 
 logy Michael Foster Gaskell, studies on nerves and 
 heart action Action of chloroform on heart Sharpey 
 Specialization of biological science Wooldridge 
 Contributions to the practice of medicine Discovery 
 of chloroform by Simpson Jenner, preventive inocu- 
 lation Bell Lister's antiseptic surgery Roy. 
 
xii Contents 
 
 CHAPTER PAGES 
 
 XII. GEOLOGY - 308-319 
 
 Great Britain, a geological microcosm William Smith, 
 rock strata Beds of rocks characterized by fossils 
 Chronological sequence Hutton and the Huttonian 
 theory Lyell and Uniformitarianism Allport, D. 
 Forbes Sorby, crystal structure Influence of local 
 surroundings The district of St. David's, oldest rocks 
 in Great Britain Aymestry limestone The Silurian 
 system Sedgwick, Cambrian rocks Miller, old red 
 sandstone Delabeche, importance of mapping The 
 Government geological survey Phillips New red sand- 
 stone Fitton and Mantell Prestwich, E. Forbes 
 Palseontological work by Davidson and others James 
 Geikie Archibald Geikie Buckland, diluvial deposits 
 Economic geology. 
 
 INDEX 321 
 
PREFACE 
 
 HPHIS book does not pretend to establish any thesis. 
 * Incidentally it may point a moral which different 
 readers will interpret in different ways. Our main 
 purpose was to give a plain account of Britain's great 
 heritage of science; an heritage that handed down 
 through several centuries of distinguished achieve- 
 ments will, if the signs speak true, be passed on to 
 the coming age with untarnished brilliancy. 
 
 A limit had to be set to the extent to which 
 contemporary science should be included, and some 
 difficulty was felt in fixing that limit. It seemed 
 desirable for obvious reasons to avoid discussing the 
 work of living men ; but no fixed rule could be enforced 
 because that work is often too much interwoven with 
 that of others who are no longer with us to be com- 
 pletely ignored. Sometimes, also, researches undertaken 
 by our present leaders have led to results that are 
 firmly established, and to have omitted them would 
 have conveyed a false idea of the part which Great 
 Britain has played in the recent progress of science. 
 In such cases we had to use our discretion in breaking 
 through a rule which as a principle we have tried to 
 adhere to. 
 
xiv Preface 
 
 It was not intended to write a complete history of 
 British science, but to lay stress mainly on its salient 
 features, without overburdening our account with work 
 which, though meritorious and perhaps precursory to a 
 real advance, did not deal with fundamental matters. 
 Our judgment probably was at fault in some cases, and 
 accidental omissions have, no doubt, also occurred. It 
 is to be expected that these will be most numerous in 
 the chapter on technical applications, where it was 
 found difficult to select from the extensive material 
 those special instances which most clearly show the 
 part that pure science has taken in the economic life 
 of the country. 
 
 The subject naturally divides itself into two great 
 groups, one dealing with the physical, the other with 
 the biological sciences, and we are respectively respon- 
 sible for the one and the other. Our thanks are due 
 to Professor Seward, Master of Downing College, Cam- 
 bridge, for kindly helping in the chapter on Botany ; 
 to Mr. H. H. Brindley, of St. John's College, Cambridge, 
 for his assistance in the chapter on Zoology ; and to 
 Professor F. G. Hopkins for help in that on Physiology. 
 The chapter on Geology was partly re-written and much 
 increased in value by the late Professor McKenny 
 Hughes, while Dr. Marr and Mr. R. E. Priestley have 
 also assisted us with advice. Extensive use has been 
 made of the " Dictionary of National Biography," and 
 of some articles in the " Encyclopaedia Britannica." 
 
Preface xv 
 
 Part of the History of Biological Science has been 
 taken, by kind permission of the Editors and of the 
 authorities of the Cambridge University Press, from 
 the "Cambridge History of English Literature." In 
 that portion of the chapter on Zoology which deals 
 with Charles Darwin considerable extracts have also 
 been made from the Presidential Address to the Zoo- 
 logical Section of the Winnipeg Meeting of the British 
 Association. 
 
 Our thanks are due to the Council of the Royal 
 Society for permission to reproduce a number of por- 
 traits, and to the Editor of " Nature " for allowing 
 the reproduction of the excellent engraving of Clerk 
 Maxwell. The portraits which accompany the last five 
 chapters were prepared from photographs kindly taken 
 by the Rev. Alfred Rose, of Emanuel College, Cam- 
 bridge, from various well-known prints. The excellent 
 likeness of Joule, taken about 1875 by Lady Roscoe, 
 now appears for the first time. 
 
 A. S. 
 A. E. S. 
 August 1917. 
 
BRITAIN'S HERITAGE OF SCIENCE 
 
 CHAPTER I 
 THE TEN LANDMARKS OF PHYSICAL SCIENCE 
 
 (Roger Bacon, Gilbert, Napier, Newton, Dalton, Young, 
 Faraday, Joule, William Thomson, Clerk Maxwell) 
 
 history of British Science begins with Roger Bacon, 
 JL the Franciscan friar, who, cutting himself adrift 
 from the scholastic philosophy of his time, rejected the 
 traditional appeal to recognized authority, and urged with 
 a powerful voice that a knowledge of Nature can only be 
 attained through experimental research and by logical 
 reasoning. Intellectually he stood high above the level of 
 his contemporaries; 1 by his writings he set the true 
 standard of scientific enquiry, and planted the first of the 
 great landmarks along the path of British science. 
 
 " There are two methods," he writes, " in which 
 we acquire knowledge, argument and experiment. Argu- 
 ment allows us to draw conclusions, and may cause us 
 to admit the conclusion ; but it gives no proof, nor does 
 it remove doubt, and cause the mind to rest in the 
 conscious possession of truth, unless the truth is dis- 
 covered by way of experience, e.g., if any man who had 
 never seen fire were to prove by satisfactory argument 
 that fire burns and destroys things, the hearer's mind 
 would not rest satisfied, nor would he avoid fire; until 
 by putting his hand or .some combustible thing into 
 it, he proved, by actual experiment what the argument 
 laid down; but after the experiment had been made, 
 his mind receives certainty and rests in the possession 
 of truth, which could not be given by argument but 
 
 1 An interesting account of the general character of scientific 
 speculations before Bacon's time has been given by Charles L. Barnes 
 (" Manch. Lit. and Phil. Soc.," Vol X. 1896). 
 
2 Britain's Heritage of Science 
 
 only by experience. And this is the case even in mathe- 
 matics, where there is the strongest demonstration. 
 For let anyone have the clearest demonstration about an 
 equilateral triangle without experience of it, his mind will 
 never lay hold of the problem until he has actually before 
 him the intersecting circles and the lines drawn from the 
 point of section to the extremities of a straight line." 1 
 In a more detailed discussion of experimental science, 
 he points to three " prerogatives " which it has over other 
 sciences. It tests the conclusions of these other sciences 
 by experience, it attains to a knowledge of truth which could 
 not be reached by the special sciences, and " it has no 
 respect for these, but investigates on its own behalf the 
 secrets of Nature, which consist in a knowledge of the future, 
 the past and the present, and the inventing of instruments 
 and machines of wonderful power." 
 
 We further note Bacon's repeated plea for the study of 
 mathematics, which he judges to be " the key and door to 
 the special sciences." 
 
 Roger Bacon was born about 1214, in the county of 
 Dorset, of wealthy parents. Having completed his studies 
 at Oxford, he seems very soon to have gained a reputation 
 by lecturing, both at Oxford and Paris, where he went 
 about 1236. He entered the Franciscan Order, and, though 
 in bad health, continued his studies, devoting part of his 
 time to optical experiments. 
 
 " During the twenty years," he writes in 1267, " in 
 
 which I have laboured specially in the study of wisdom, 
 
 after abandoning the usual methods, I have spent more 
 
 than 2,000 on secret books and various experiments and 
 
 languages and instruments and mathematical tables, etc." 
 
 Bacon found a friend in Pope Clement IV. , an enlightened 
 
 Frenchman, who,.having been a lawyer and judge, took orders 
 
 after his wife's death and rapidly rose in the Church. In 
 
 1263 Clement was appointed papal legate in England, and 
 
 it was probably then tlaat he came to hear of Bacon's 
 
 writings. When elected Pope, two years .later, he asked 
 
 1 The translation (with a slight modification) is that given by 
 Prof. R. Adamson (see " Cbjnjnejnoration JCssays on Roger Bacon," 
 edited by A. G. Settle, p. 18). 
 
Roger Bacon 3 
 
 for fair copies of Bacon's works, who, thinking that nothing 
 he had yet written was good enough, set out on a more 
 ambitious undertaking, of which the " Opus Majus " was the 
 first instalment. In this work he displayed such indepen- 
 dence of thought, and attacked the prevailing ideas so 
 forcibly, that his opponents were converted into bitter 
 enemies. They saw their opportunity and used it when 
 Clement died. Accusations of heresy were raised, and 
 Roger Bacon was condemned to prison by the General of the 
 Franciscan Order in 1277. He remained in captivity till 
 shortly before his death, which took place in 1292. 
 
 With Roger Bacon England took the lead in laying the 
 foundation of modern science. While the scholastic tradi- 
 tion held the whole of Europe in bond he stood alone, 
 fearlessly holding up the torch of enlightenment; but its 
 rays fell on eyes that could or would not see. More than 
 three barren centuries separated Bacon from the next great 
 scientific figures, William Gilbert and John Napier. 
 
 Gilbert (1540-1603) has been called the father of electric 
 and magnetic science. He belonged to an old Suffolk family, 
 was born at Colchester, and after a distinguished career 
 at Cambridge, spent three years in Italy and other parts 
 of Europe. On his return he settled down in London as a 
 medical practitioner, and soon gained a reputation which 
 secured him many honours, and among them the appoint- 
 ment as physician to Queen Elizabeth. His chief work is 
 described in a volume published in 1600 under the title of 
 " De magnete, magnetisque corporibus et de magno magnete 
 tellure." 
 
 It was known to the Greek philosophers that a, certain 
 mineral originally found in Magnesia had tin pow^r of 
 attracting small pieces of iron. In the twelfth .century the 
 knowledge of the compass was brought to JSurope. jChe 
 Chinese, who had been familiar with it jn very early times, 
 already knew that the clireotion in which the needle points 
 was a little to one side of North, and Columbus discovered 
 that this deviation differed in different localities. Nearly 
 a century later, Robert Norman, a British sailor, had 
 observed that the .force which acted on the needle was not, 
 *s bad generally beeto assumed, directed upVards towards 
 
 A 2 
 
4 Britain's Heritage of Science 
 
 the pole star, but downwards, and in 1576 he measured 
 the angle between the horizontal and the direction of the 
 magnetic needle, which we now call the magnetic dip, and 
 found it to be nearly 72 in London. Such was the know- 
 ledge at Gilbert's disposal when he began his celebrated 
 researches. The word " loadstone " for the magnetic mineral, 
 derived from lead-stone, indicates how the main interest in 
 magnetic properties had been concentrated in their use for 
 purposes of navigation. Gilbert's object, on the other 
 hand, was chiefly scientific. The high position which he 
 occupies in the history of science is not merely due to his 
 discoveries, but to a great extent on his being the first man 
 of science who gave effect to Roger Bacon's teaching, 
 possessing the power and will to draw logical conclusions 
 from his experiments, and to verify by new experiments 
 the wider views suggested by these conclusions. 
 
 Mapping out the directions in which a freely suspended 
 magnetic needle sets at different points on the earth's 
 surface, it appears to us a simple matter to infer that the 
 earth as a whole behaves like a huge magnet. A diagram 
 seems to be all that is required to complete the deduction. 
 But the world at the time was not accustomed to logical 
 reasoning of this kind. It was necessary, therefore, to 
 enforce conviction by corroborative evidence, which Gilbert 
 supplied, showing that the earth, so far as could be tested, 
 possessed all the properties of a magnet. He pointed out 
 that rods of iron lying about become magnetic under its 
 influence, just as when placed near magnetized iron, and 
 he noted that the effect is the stronger the more nearly 
 the direction of the rods coincides with the direction in 
 which a suspended needle comes to rest. Gilbert further 
 constructed a" magnetic sphere, and suspending small 
 .magnets by thin fibres, he examined how these set in 
 different directions at different points on the sphere. He 
 could thus, on a small scale, reproduce a model of the 
 earth as a magnet, and. observing that the magnetic forces 
 extend beyond the surface of his " terellum," was led to 
 speculate on the possible action of terrestrial magnetism on 
 the moon, and the mutual magnetic effects of planets on 
 each other. We readily forgive him if in these cosmic 
 
William Gilbert 5 
 
 speculations he travelled beyond the justifiable limits of his 
 experimental facts. 
 
 In his electrical researches Gilbert had the same wide 
 outlook. Amber, when excited by friction, was known to 
 attract light bodies; why he asked himself should special 
 properties be confined in one case to iron and in another to 
 amber? He tried but failed to find a magnetic action on 
 water and other bodies, but discovered that the property 
 of amber was shared by a large number of substances, 
 such as glass, sulphur, and the precious stones. He was 
 the first to note that electric effects persist longer in dry 
 air than in wet weather, that an electrified body loses its 
 power when moistened with water or spirit, or when glowing 
 coal is brought near to it. We also owe to him the word 
 " electricity " (derived from " rj\Tpov ", the Greek word for 
 amber) ; though only in the form of the adjective. " Vim 
 illam," he writes, " electricam nobis placet appellare, 
 quse ab humore provenit." In a posthumous work he 
 declares himself to be an adherent of the Copernican 
 doctrine, and shows a clear scientific perception, as when 
 he explains that there is no intrinsic property of " levity," 
 but that when light bodies are seen to ascend they do so 
 under the influence of the pressure of the surrounding 
 heavier bodies. 
 
 Galileo, 1 almost the only man of science born in the 
 sixteenth century who stands on an intellectual level with 
 Gilbert, appreciated his work. In the third of the famous 
 " Dialogues " he gives an account of it, and Salviati, the 
 imaginary person who is made to express Galileo's own 
 views, mentions Gilbert's book, " which might not have 
 come into my hands if a peripatetic philosopher had not 
 presented it to me, for the reason, I believe, that he did 
 not wish to contaminate his own library with it." After 
 referring to some of Gilbert's experiments, Salviati further 
 says : 
 
 " I highly praise, admire, and envy this author for 
 
 having formed such a stupendous conception on a 
 
 1 The name is given in its usual form, but it sounds rather like 
 calling a man Thomas whose full name is Thomas Thomasson. Galileo's 
 father was Vincenzio Galilei ; his own full name Galileo Galilei. 
 
6 Britain's Heritage of Science 
 
 matter which has been treated by many sublime 
 intellects, but solved by none; he appears to me also 
 to deserve the highest praise for his many and true 
 observations, putting to shame the lying and vain 
 authors who write not only of what they know, but 
 also of what they hear from the silly crowd, without 
 satisfying themselves by experiment of what is true 
 perhaps, because they do not wish to shorten their 
 books. What I should have desired in Gilbert is that 
 he would have been a little more of a mathematician, 
 and especially well schooled in geometry, the practice 
 of which would have made him less inclined to accept, 
 as conclusive proofs, what are only arguments in favour 
 of the deductions he draws from his observations. . . 
 . . . I do not doubt that in the course of time this 
 new science will be perfected by new observations, and 
 by true and cogent demonstrations. But the glory 
 of the first inventor will not be diminished thereby; 
 I do not esteem less, but, on the contrary, admire, the 
 first inventor of the lyre (though probably his instru- 
 ment was roughly constructed and more roughly played), 
 much more than the hundred other players who, in the 
 succeeding centuries, have brought his art to exquisite 
 perfection." 
 
 Coming from Galileo this was high praise, indeed. 
 The next landmark was planted by a man of equal 
 power but different type of intellect. 
 
 John Napier, of Merchiston, descended from a distin- 
 guished Scotch family, which, in the fifteenth century, 
 included three Provosts of Edinburgh among its members. 
 His father, Sir Archibald Napier, was Justice Deputy under 
 the Earl of Argyll, and Master of the Mint. John was 
 born at Merchiston Castle in 1550; after a short period 
 of study at the University of St. Andrews, he probably 
 spent some time in foreign travel, but returned to Scotland 
 at the age of twenty-two. Though involved in the political 
 and religious controversies of his age, he devoted his spare 
 time to the study of mathematics, and, what to him seemed 
 of greater importance, the writing of a book on the Apoca- 
 lypse. This mathematical work culminated in the discovery 
 
John[Napier 7 
 
 of logarithms, and gave to the world a method by means 
 of which multiplication is converted into addition, division 
 into subtraction, and the extraction of square or cube root 
 into a division by two or three respectively. The scientific 
 merit of introducing logarithmic functions into the domain 
 of mathematics is surpassed by the incalculable importance 
 of assisting the complicated numerical calculations which 
 were vital to the progress of astronomy and of other branches 
 of science. Without explaining the objects which Napier 
 primarily had in view, or the steps by which he arrived at 
 his final results, we may justify the prominent position 
 here given to him in the history of science by quoting a 
 few passages from an article contributed by Dr. J. W. L. 
 Glaisher to the " Napier Tercentenary Memorial Volume " : 
 " The process of multiplication is so fundamental 
 and direct that, from an arithmetical point of view, 
 it might well be thought to be incapable of simplifica- 
 tion or transformation into an easier process, so that 
 there would seem to be no hope of help except from 
 an apparatus. But Napier, not contented with such 
 aids, discovered by a most remarkable and memorable 
 effort of genius that such a transformation of multipli- 
 cation was possible, and he not only showed how the 
 necessary table could be calculated, but he actually 
 constructed it himself. That Napier at a time when 
 algebra scarcely existed should have done this is most 
 wonderful; he gave us the principle, the method of 
 calculation, and the finished table. 
 
 " The * Canon Mirificus ' is the first British contribution 
 to the mathematical sciences, and next to Newton's ' Prin- 
 cipia ' it is the most important work in the history of the 
 exact sciences that has been published in Great Britain, 
 at all even' s until within the memory of living persons. 
 
 " In whatever country the ' Canon Mirificus ' had 
 been produced, it would have occupied the same com- 
 manding position, for it announced one of the greatest 
 scientific discoveries ever made." 
 
 Independently of his work on logarithms, Napier's con- 
 tributions to spherical trigonometry would alone have 
 secured him a high position among mathematicians. 
 
8 Britain's Heritage of Science 
 
 The interval between the death of Gilbert in 1603 and 
 that of Napier in 1617 marks the period of Galileo's astro- 
 nomical discoveries and of Kepler's fundamental work on 
 planetary orbits. The world was now waiting for a great 
 generalization, but Kepler passed away and Galileo died an 
 old and broken man before one was born who surpassed 
 both in genius and power as much as they had excelled those 
 who went before them. 
 
 From the seventeenth century onwards, British science 
 has continuously advanced, sometimes rushing ahead with 
 torrential energy, sometimes in a smooth and almost imper- 
 ceptible flow ; at one period chiefly concentrated in the uni- 
 versities; at others almost entirely kept alive by private 
 enthusiasts ; but taken as a whole never losing contact with 
 past achievements or ceasing to foreshadow future conquests. 
 To appreciate correctly the different stages of the advance, 
 we must distinguish between the slow work of accumulating 
 facts or proving and disproving theories and the generation 
 of new ideas which suddenly alter the whole trend of 
 scientific thought. Such creations form the seven land- 
 marks which bring us to nearly the end of the nineteenth 
 century : Newton's establishment of the law of gravitation, 
 Dalton's atomic theory, Faraday's electric discoveries, 
 Young's contribution to the wave-theory of light, Joule's 
 foundation of the conservation of energy, Kelvin's demon- 
 stration of the dissipation of energy; finally, Maxwell's 
 formulation of the electro-magnetic theory of light. 
 
 Roger Bacon made an acute remark to the effect that 
 while in mathematics we can proceed from the simple to 
 the more complicated, it is impossible to do so in other 
 branches of science, because Nature does not, as a rule, 
 present us with the simple phenomenon. The whole history 
 of science shows how it is always struggling in search of the 
 simple starting point with respect to which we are constantly 
 driven to modify or even reverse our ideas. Thales believed 
 water to be the elementary substance from which everything 
 else could be derived, Anaximenes thought it was air, and 
 Heraclitus substituted fire, while, according to Pythagoras, 
 it was the relations between integer numbers which formed 
 the foundation of all science. 
 
Sir Isaac Newton 9 
 
 Take the case of " rest " and " motion." At first sight 
 it seems obvious that the former is the simpler phenomenon ; 
 but our trouble begins when we try to define " rest." Dis- 
 regarding this difficulty, let us ask ** What is the simplest 
 kind of motion ? " Every schoolboy now could give the" 
 answer : "A uniform motion in a straight line " ; but he 
 would be sorely puzzled if he were required to give an example 
 of a body moving with uniform motion in a straight line, for 
 such a thing does not exist. The Greek philosophers kept 
 more in touch with realities when they considered motion 
 in a circle to be the simplest of its kind, because they had 
 observed that the stars describe circles in the sky, and they 
 could artificially produce circular motion by tying a weight 
 to a string and whirling it round. As astronomy advanced, 
 and the motion of the planets were further investigated, 
 it became more and more difficult to reduce everything to 
 circular motion. All efforts to persevere in such attempts 
 finally broke down when the laws regulating the fall of 
 bodies from a height were discovered. The straight line 
 motion although never directly brought within the range of 
 observation then took its place as the simpler basic idea. 
 
 Sir Isaac Newton (1643-1727) formulated the laws of 
 motion ; they - have formed ever since the foundation of 
 physical science, and a few words must be said as to their 
 significance. Our first idea of " force " is derived from 
 muscular sensation. We push a body, and see it change its 
 place, and are conscious that we can ourselves be made to 
 move by an application of muscular force from outside. 
 From this it is natural, though perhaps not altogether logical, 
 to conclude that every change of motion which we observe 
 in a body is due to some push or pull on that body. This 
 imaginary push or pull we call a force. The first law, 
 originally due to Galileo, asserts that absence of force does 
 not necessarily imply that a body is at rest ; it may be moving, 
 but, if so, it continues to move in a straight line with unaltered 
 velocity. The second law allows us to measure a force, and 
 may be said to have been first applied by Huygens. The 
 third law asserts that whenever we observe a change of 
 motion in a body there must be an equal and opposite 
 change of motion in another body or system of bodies. This 
 
10 Britain's Heritage of Science 
 
 is the law of u action and reaction," which has played so 
 important a part in the history of science. 
 
 Having accurately defined what is meant by change of 
 motion, Newton in his " Principia " establishes a number 
 of propositions relating to the motion of a body acted on 
 by a force directed to a fixed centre. The Copernican 
 hypothesis that the earth and planets are in motion round 
 the sun, replacing the older view which believed the earth 
 to be the centre of the universe, was at that time generally 
 accepted by scientific men, and Kepler had formulated three 
 laws defining the orbits of the planets. Newton's pro- 
 positions, applied to Kepler's laws, proved that the movements 
 of the planets may be accounted for by imagining attracting 
 forces to act between the sun and the planets diminishing 
 in proportion to the squares of the distances. If this attrac- 
 tion be accepted, it is natural to identify it with the force 
 that keeps the moon in its orbit round the earth, and finally 
 with that which we observe directly when a body falls down 
 from a height. But it had to be proved that the intensity 
 of gravitation at the surface of the earth and that acting 
 on the moon were related to each other according to the 
 law deduced from the planetary motions; in other words, 
 as the distance between the centres of the earth and moon 
 is 60 times the earth's radius it had to be shown that 
 the gravitational force at the surface of the earth is 3,600 
 times as great as that which keeps the moon in its orbit. 
 The calculation is easily made if we know the length of the 
 earth's diameter, and this having been ascertained with 
 sufficient accuracy by Picard in France shortly before the 
 publication of the " Principia," Newton had the satisfaction 
 of finding an almost perfect agreement. His theory was 
 confirmed, and it was definitely proved that the motion of 
 the planetary system, as well as the behaviour of heavy 
 bodies on the surface of the earth, could all be deduced from 
 the general proposition that every particle of matter attracts 
 every other particle with a force which varies in the inverse 
 ratio of the square of the distance. 
 
 Commentators on Newton's work frequently draw atten- 
 tion to the delay in publishing for ten years or more the 
 results of his calculations, because when they were first 
 
Sir Isaac Newton 11 
 
 completed there seemed to be a discrepancy of about 11 per 
 cent, between the value of gravity at the surface of the earth 
 as deduced from the moon's orbit, and that which can be 
 observed directly. It has even been said that, for a time, 
 he rejected the theory altogether, but there is reason for 
 believing that the delay was due to one uncertain step in the 
 argument which might have caused an error and accounted 
 for the disagreement. Newton consequently deferred publi- 
 cation until he could satisfy himself with regard to this 
 doubtful point. The attraction of the earth as a whole is 
 made up of the attraction of its separate parts. When the 
 attracted body is at a distance, no great error can be committed 
 by assuming the earth's mass to be concentrated at its centre, 
 but it might be otherwise, if it is near the surface. Ulti- 
 mately, Newton proved that, when the law of attraction 
 is that of the inverse square, we may indeed take the 
 attraction of a sphere at all distances to be the same as that 
 of an equal mass placed at its centre. The real cause of the 
 disagreement was then found to be the inaccurate value 
 originally adopted for the circumference of the earth. When 
 the measurements of Picard became known the agreement 
 was found to be complete. 
 
 The importance of Newton's discovery extended far 
 beyond its immediate results; its wider and far-reaching 
 effect lay in the demonstration it supplied that by means 
 of a rigorous mathematical analysis the facts of Nature can 
 be represented not only in the vague speculative manner 
 which then was considered sufficient by the majority of 
 philosophers, but definitely and quantitatively, allowing 
 a numerical test to be applied. Apart from the philosophic 
 value of a rigorous treatment, the human mind is always 
 strongly (on occasions too strongly) impressed by numerical 
 coincidences. Newton's investigation which enabled him to 
 calculate the force of gravity at the earth's surface from the 
 time of revolution of the moon therefore earned conviction, 
 and was accepted by the majority of his countrymen ; but 
 it took some time before the continent of Europe gave its 
 full assent, and the criticisms which were raised illustrate 
 the danger of taking up too definite an attitude with regard 
 to the ultimate starting point representing the simple 
 
12 Britain's Heritage of Science 
 
 phenomenon from which everything else should be derived. 
 In France, at any rate, the influence of Descartes' philosophy 
 was paramount, and Descartes had truly started from the 
 beginning : " I think, therefore I exist," was to him the 
 only justifiable & priori assertion to make ; everything else 
 was to be deduced from that proposition. With a most 
 powerful and original intellect, he had developed an ingenious 
 and in many ways logical and consistent system, in which 
 there was no room for the motion of .any body except that 
 which was brought about by the impulse of another body 
 which itself was in motion. If the planets revolve round 
 the sun, it was to him, therefore, clear that they must be 
 carried along by an invisible medium whirling round the 
 sun. Hence his hypothesis of gigantic vortices filling all 
 space. This is not the place to explain how all phenomena 
 in Nature were supposed to be accounted for by such means, 
 but it is clear that the hypothesis was elastic, and could be 
 varied, added to, and infinitely extended, whenever some 
 difficulty arose. What concerns us here is that it seemed 
 to go to the foundation of things the origin of motion 
 and to those trained up in the doctrine of vortices, the mere 
 postulate of a universal attraction to account for one set 
 of natural phenomena, disregarding all the rest, seemed to 
 be a retrograde step. Hence very naturally arose consider- 
 able opposition, and it was mainly those who disagreed with 
 Descartes and believed in the possibility of action at a 
 distance, who inclined towards Newton. But this was 
 really beside the point, because Newton expressly guards 
 himself against the implication that his theory necessarily 
 involved action at a distance, the origin of gravitational 
 force being in no way prejudged by the affirmation of its 
 existence. We have here an example of the often re- 
 curring struggle between a general but indefinite hypothesis 
 which suggests many things, but cannot be submitted to a 
 numerical test, and what is characteristic of the Cambridge 
 school of investigation. This school, which had its period 
 of triumph in the nineteenth century, clearly defines a 
 problem, confining it to such limits, wide or narrow, as will 
 convert it into a precise problem which can be formulated 
 and submitted to mathematical analysis. There must 
 
Sir Isaac Newton 13 
 
 always be a definite answer to a definite question, and, 
 unless the mathematical difficulties v are insuperable, the 
 consequences of any assumption may be obtained in a form 
 in which they can be tested, not only as to their general 
 nature but also as to their numerical values. The result 
 may not be far-reaching, but within its limited field it is 
 definite. We may not have penetrated to the foundation 
 of the building, but we shall have mapped out one of its 
 apartments and perhaps reached a fresh starting point. 
 
 Two centuries and a quarter have now passed since the 
 publication of Newton's " Principia," and during that time 
 our astronomical measurements have become more and 
 more accurate. Though the mathematical analysis has 
 sometimes found it difficult to keep pace with the improved 
 methods of observation, Newton's simple law of the inverse 
 square has hitherto always been found sufficient to explain 
 apparent irregularities in the motion of the celestial bodies, 
 with perhaps the solitary exception of an irregularity in 
 the motion of Mercury, which may ultimately be cleared up 
 without calling in some other agency or perhaps is destined 
 to open out an entirely new aspect of gravitation. 
 
 The most precious heritage bequeathed to us by Newton 
 is this : He has given us the confidence that, complicated 
 as the problems of Nature may be, they are soluble if we 
 confine ourselves to a limited and definite range, and follow 
 up by irrefragable logical or mathematical reasoning the 
 consequences of clearly-defined premises. 
 
 By his laws of motion Newton laid the foundation of 
 modern dynamics. The next great advance relates to 
 the constitution of "matter." Common experience shows 
 that . each .piece of matter may change in shape or volume ; 
 it even seemingly vanishes, as when water evaporates, or 
 is freshly formed, as when dew is deposited on. a blade of 
 grass. If this be kept in mind, we are forced to concede, 
 in opposition to the school which, professes to. reject all 
 theories, that an introspective philosophy entirely detached 
 from observation may lead to a truth hidden from the pure 
 experimentalist. To perceive that matter in spite of all 
 appearances is indestructible goes beyond the limits of 
 our direct observation; and a science without imagination 
 
14 Britain's Heritage of Science 
 
 confining itself to that which it can see would have grown 
 very slowly indeed. We owe that much to the Greek 
 philosophers, that they took a wider view, and at any rate 
 tried to evolve a system which would satisfy our sense 
 of harmony in the perception and interpretation of Nature. 
 Their imagination frequently led them astray, but as often 
 prepared the way for the evolution of the correct view. The 
 idea that all matter is composed of separate small particles 
 which cannot further be subdivided appears very early 
 among the Greek philosophers. Anaxagoras, in the fifth 
 century before Christ, assumed the existence of indestructible 
 and immutable elements of which all bodies are composed, 
 and called them " seeds." Half a century later, Democritus 
 first used the word " atom," but differed from Anaxagoras 
 by ascribing the different properties of bodies not to a differ- 
 ence in kind, but merely to one in shape and arrangement. 
 Aristotle rejected this hypothesis completely, and his 
 unhappy doctrine, apparently borrowed from Indian sources, 
 which treats matter as an embodiment of mixtures in different 
 proportions of the imaginary elements, fire, earth, water, 
 and air, had a most paralysing influence on the history of 
 science. The atomic theory consequently remained through 
 centuries the subject of metaphysical speculations and the 
 plaything of philosophers; as the foundation of chemical 
 science, it takes its place only in modern times. But 
 one great obstacle had to be removed. The chemistry 
 of the eighteenth century was entirely under the influence 
 of an erroneous theory of combustion, according to which 
 inflammable bodies contained an invisible substance 
 " phlogiston "^-showing itself as a .flame on being expeUed, 
 and no progress was possible until the true nature of com- 
 bustion had been demonstrated by the eminent French 
 chemist Lavoisier. .His explanations were so simple and 
 convincing that ifr js difficult to understand why the atti- 
 tude taken up by JEngJisfr chemists with regard to them 
 was entirely hostile. Cavendish, like Black and Priestley, 
 adhered to the phlogiston theory, even when the latter, by 
 his discovery of oxygen, .had supplied the c.hief weapon by 
 which it ultimately .fell. 
 
 Robert Boyle (1627-1691) had clearly shown how a 
 
John Dalton 15 
 
 sharp distinction between elementary and compound bodies 
 could be drawn, and even explained the difference between 
 mixtures and chemical compounds. But it was only when 
 phlogiston had been finally abandoned that the way was 
 prepared for our present conception of the constitution of 
 matter. This is indelibly connected with the name of John 
 Dalton (1766-1844), who taught us that the material uni- 
 verse contains a certain number of elementary substances, 
 each possessing, as its ultimate constituent, a distinctive 
 atom which cannot be split up farther by chemical or 
 physical means. There are, therefore, as many different 
 kinds of atoms as there are elementary substances. The 
 atoms of each element are alike in every respect, and have 
 the same weight. When atoms of different elements enter 
 into close union with each other, they form what Dalton 
 called " compound atoms," or, according to our present 
 nomenclature, " molecules " ; these are the ultimate con- 
 stituents of compound bodies. 
 
 Dalton's first scientific interests, which he preserved 
 through life, were connected with meteorology. He was 
 led to his chemical investigations through attempting to 
 find a reason for the uniformity in the mixture of gases 
 at different levels of the atmosphere, being much puzzled 
 to know why the oxygen, nitrogen, and aqueous vapour 
 did not arrange themselves in layers according to their 
 density, as when oil rises to the top if mixed with water. 
 His difficulty was mainly due to the peculiar ideas he had 
 formed of the nature of a gas. For a time he seems to 
 have adopted the correct view that all gases at the same 
 temperature and pressure have the same number of ultimate 
 particles in unit volume, but he abandoned it because ,it 
 did .not seem to Mm to lead to tfce observed .intenningjing 
 of gases irrespective of their density. ,IJe then invented 
 a , rather Janciful .hypothesis wl^ich drew a distinction between 
 the density of a& Atom and its weight, and he tried to 
 find -some connexion between the two. This led him 
 to investigate atomic weights. Dalton's temperament and 
 methods of procedure were different from those of the 
 other leaders of science whose work is under review. He 
 is rightly considered tP be tl^e originator of the principle 
 
16 Britain's Heritage of Science 
 
 of multiple proportions, but he did not base his results 
 so much on accurate measurements, as on the logical 
 coherence of the system he advocated. In its simplest 
 form, this principle means that if one atom of an element 
 can combine with one, two, or more atoms of another, the 
 weight of the compound molecules formed must increase 
 by equal steps. But in the " New System of Chemical 
 Philosophy " (first published in 1810), though examples 
 are given in illustration, no systematic attempt is made to 
 reach an accuracy sufficient to establish a proof. To Dalton 
 the principle was obvious, and he was mainly interested in 
 determining the relative atomic weights and showing, for 
 a number of simple substances, how many atoms of each 
 element are combined to form the compound molecule. 
 The most important portion of the work deals with sub- 
 stances in which one or all of the combined elements are 
 gaseous, and he depends a good deal on the measurement 
 of volumes before and after combination. As the methods 
 of drying and otherwise purifying gases were imperfectly 
 understood at the time, the figures which he obtained were, 
 according to our standard, very inaccurate; nevertheless, 
 the power and success with which he treated the subject 
 very soon convinced other chemists that the foundations 
 of his system were correct. 
 
 Dalton's evidence was cumulative rather than indi- 
 vidually decisive, and it may be said that he convinced 
 the scientific world more by the strength of his own con- 
 victions than by the experimental proofs he supplied. 
 
 The total number of elements known in Dalton's time 
 was twenty-three, but others were soon added, until, towards 
 the middle of last century, over 'sixty elementary sub- 
 stances were recognized. At present -we have reason to 
 believe that the number' is strictly limited. 1 Whatever 
 opposition there was to Dalton's views it. died. out quickly, 
 though some philosophers found much that was distasteful 
 in the immediate result of his teaching. There is, indeed, 
 at first sight, something repellent in the idea that there 
 should be one number, whether it be sixty-three or ninety- 
 two, raised in importance so far above all others that it 
 
 1 See the result of Moseley's researches, page 185, 
 
John Dalton 
 
 From a painting by K. R.Faulkner 
 in the possession of the Poyal Society 
 
John Dalton 17 
 
 fixes the limits of creation, as regards the possible diversity 
 of matter. But all such scruples must be set aside, for 
 the atom of Dalton is only a stepping-stone to a higher 
 level of knowledge. The chemist knows what he means 
 by an atom, and when he is building up his compounds 
 with them, he is not concerned with the question of their 
 ultimate constitution; just as the builder who constructs a 
 house with bricks need not trouble to enquire whether the 
 substance of the bricks is continuous or made of up of mole- 
 cules. The merit of Dalton f s atomic theory, like that of then 
 law of gravitation, is that it sets certain boundaries beyond L 
 which our imagination need not wander for the moment ; \ 
 it defines a limited problem and for the time solves it. 
 
 Speculations on the nature of light could not fail to 
 attract the attention of the old philosophers; but, for our 
 present purpose, we need not go farther back than to the 
 rival theories of Newton and Huygens. The former led, 
 no doubt, by his predilection for an accurately definable 
 starting point from which he could proceed to develop the 
 consequence of a theory with mathematical precision 
 adopted the view (to be found already in the writings of 
 Democritus), that light consists of small corpuscles emitted 
 by the luminous body. The rectilinear propagation of light, 
 and its bending as it passes from one transparent body 
 to another, could easily be explained on this theory, and 
 though it was incapable of dealing with the more complex 
 properties of light, it received general support until the 
 middle of last century. 
 
 It was apparently Hooke who first suggested that light 
 was an undulatory motion in an all-pervading medium, but 
 Huygens has the merit of showing how this hypothesis could 
 explain luminous phenomena with a precision at least equal 
 to that of the corpuscular theory. There being at that 
 time no crucial test to decide between the rival theories, 
 the cleavage of scientific opinion took place along the line 
 of separation between metaphysical tendencies. Those who 
 disliked the idea of a vacuum and action at a distance 
 inclined towards Huygens, others towards Newton. Com- 
 promises have never been favoured by men of science, and 
 as the theory of gravitation starts from an assumption 
 
 B 
 
18 Britain's Heritage of Science 
 
 implying action at a distance, those who were guided by 
 Newton considered it to be almost a sacrilege to go further 
 than the master. To them action at a distance became 
 an universal dogma, and the undulatory theory had no chance 
 until it could produce a conspicuous success by explaining 
 experimental facts, which were not amenable to treatment 
 by the more favoured hypothesis. 
 
 The analogy of light to sound attracted the attention 
 of Thomas Young (1773-1829), and was emphasized by 
 him in a paper published in the Philosophical Transactions 
 of the Royal Society in 1800. Here, again, it was the 
 detailed examination of one special aspect of the problem 
 which led to the decisive advance. Some of the charac- 
 teristic features of a wave motion may be illustrated by 
 an examination of the waves passing over a sheet of water. 
 Everyone is familiar with the circles spreading out from 
 a centre when a stone is thrown into water; each point 
 of the surface as the wave passes over it rising and falling 
 alternately. If two stones are thrown, and enter the water 
 at points near each other, each will start its own system 
 of circles. These will overlap, and the question arises : 
 how does the motion at any point of the surface of the 
 water depend on the motion due to each wave separately? 
 The question is so simple, and the answer seems so easy, 
 that many must have passed it by as hardly worth 
 recording; but Young saw that it was the key to the 
 position : each wave produces its own effect without inter- 
 ference from the other. If, under the influence of one set 
 of waves, a point were raised one inch above the undisturbed 
 level, and the other set caused by itself alone an elevation 
 of two inches, then the combined effect would be a rise of 
 three inches. If the effect of the second wave at any time 
 were a depression of two inches, the effect of the first being 
 the same as before, the depression of two inches would 
 overbalance the rise of one inch, and leave a depression 
 amounting to one inch. If the rise due to one set of 
 waves equals exactly the fall due to the other, there will 
 be neither a rise nor a fall, but the point will remain 
 at rest. This, in a few words, is the principle of " super- 
 position of motions," which applies only approximately to 
 
Thomas Young 19 
 
 water waves, but generally to all small displacements such 
 as those we suppose to occur in the propagation of light. 
 The important point to notice is, that two rays of light 
 falling on the same point can neutralize each other's effect, 
 so that there is darkness, where each ray separately produced 
 illumination. 
 
 The colours of thin plates could not be explained onl 
 Newton's theory, unless the corpuscles of light were endowed / 
 with some peculiar attributes, and it occurred to Young 
 that a more natural explanation presented itself by con- 
 sidering the overlapping of waves which occurs whenever 
 two rays of light meet at a point. This led him to design 
 new experiments in which two sets of light waves could ^ 
 be made to overlap in such a manner that the crest of 
 one set falls exactly over the hollow of the other, so that 
 the two waves neutralize each other. By measuring the 
 distances of the dark regions from each other, he showed 
 how the lengths of waves could be determined. All seemed 
 simple and straightforward, when a formidable difficulty 
 arose, through the discovery of a new property of light, 
 now called polarization. This seems to have baffled Young 
 to such an extent that he began to be doubtful of his 
 theory. It was only when the French engineer, Fresnel 
 (who rediscovered the cause of the " interference " of light 
 and corrected Young's explanation of " diffraction "), had, 
 in conjunction with Arago, formulated more precisely the 
 experimental conditions under which polarized light may 
 interfere, that the clue to the solution was found. In a 
 letter to Arago, dated 12th of January 1817, Young 
 suggested that the peculiarity of waves which gave rise 
 to polarization might be due to the direction in which the 
 motion takes place. In a wave of sound, each particle 
 of air moves backward and forward in the direction in 
 which the sound is propagated, so that if the sound 
 spreads out from one point, the motion is directed every- 
 where to or from the centre. In a wa er wave propagated 
 over a horizontal sheet of water, on the other hand, the 
 direction is mainly up and down. It occurred to Young 
 that if a wave of light resembled that spreading over a sheet 
 of water, two disturbances propagated in the same direction 
 
 B 2 
 
20 Britain's Heritage of Science 
 
 might still show different effects, for if the wave comes 
 straight towards us the direction of motion might be hori- 
 zontal or vertical. 
 
 If the originality of a discovery can be gauged by the 
 opposition it rouses, Young's work takes a high rank. In 
 referring to his explanation of the interference of light 
 (Edinburgh Review, Vol. I., p. 450) Lord Brougham 
 expresses the opinion that it " contains nothing which 
 deserves the name either of experiment or discovery," 
 and concludes by " entreating the attention of the Royal 
 Society, which has admitted of late so many hasty and 
 unsubstantial papers into its Transactions." 
 
 As regards the suggestion of transverse vibrations, one 
 might have imagined that the analogy of water waves 
 would have secured its being more readily accepted, but 
 the passage from two to three dimensions is by no means 
 obvious, and its difficulties presented themselves with 
 special force to mathematicians. When Fresnel had inde- 
 pendently recognized that the experimental facts could 
 not be explained except by accepting this transverse 
 motion, he placed the wave theory of light on a new 
 and firm basis ; but he lost the collaboration and sympathy 
 of his colleague Arago, who, up to the time of his death 
 in 1853, would not recognize the possibility of a spherical 
 wave in which the motion was not entirely radial. Even 
 Laplace and Poisson were strongly antagonistic to the idea 
 of spherical waves with transverse displacements ; their 
 difficulty was a very substantial one, solved only at a later 
 date by the investigations of Stokes. 
 
 Of all men who have spent their lives in the search for 
 experimental discoveries, no one has ever approached 
 Michael Faraday (1791-1867) in the number, the variety, 
 or the importance of the new facts disclosed by his labours. 
 If we wish to select from among these discoveries one or 
 two which have had a predominant influence in directing 
 scientific efforts into new channels, we must give the first 
 place to his researches on electro-magnetic induction. 
 Starting from the discovery that an electric current suddenly 
 generated or suddenly stopped caused an instantaneous 
 current in a wire placed in its neighbourhood, he proceeded 
 
Michael Faraday 21 
 
 to show that a current passing through a wire which is 
 made to move in the neighbourhood of another circuit 
 induces similarly a current in the latter; and finally he 
 extended these facts to the effects of moving magnets in place 
 of electric currents. Faraday thus not only prepared the way 
 for a consistent theory of electro-magnetic action, but proved 
 that it was possible to convert electric energy into mecha- 
 nical power, or, reciprocally, obtain electric energy by an 
 expenditure of mechanical work. In other words, the whole 
 of the present electric industry is based on his discoveries. 
 
 As a second example of Faraday's experimental genius, 
 we may take his work on the chemical decomposition of a 
 liquid when an electric current is sent through it. Though 
 this process of electrolysis had been used with great success 
 by Sir Humphry Davy, its laws were not fully understood. 
 Faraday proved that the total quantity of the substance 
 decomposed depends only on the total quantity of electricity 
 which has passed, independently of whether it be a strong 
 current acting for a short time, or a weak current acting 
 for a correspondingly longer time. He also discovered a 
 most important relation between the amount decomposed 
 and the chemical constitution. In his own words : "If 
 we adopt the atomic theory and phraseology, then the 
 atoms of bodies which are equivalents to each other in 
 their ordinary chemical action, have equal quantities of 
 electricity naturally associated with them." How pregnant 
 these words are as forerunners of the most recent researches 
 in electricity will appear in due course. 
 
 During a long life Faraday piled his discoveries one 
 upon another in almost continuous succession, yet they 
 are united by a common thread of thought applied both 
 consistently and persistently. New facts were brought 
 to light, not through an omnivorous desire to penetrate 
 into detached bits of unexplored regions, but by the wish 
 to find a common link binding together all the forces which 
 in each branch of Physics gravity, electricity, magnetism 
 and chemistry had been treated as peculiar to that branch. 
 His manner of looking at things was so different from that 
 of other scientific men of his time, and in some ways so 
 prophetic, that a few words must be said with regard to 
 
22 Britain's Heritage of Science 
 
 o 
 
 it, more especially as it was much more thorough-going 
 than is generally represented. 
 
 Matter is only known to us through the forces which 
 it exerts, and we cannot, therefore, reason about matter 
 at all, but only about forces. This truth was so strongly 
 impressed on Faraday's mind, that he warned scientific 
 men against the use of the word " atom," because it fixed 
 their attention on what he considered to be unessential. He 
 could only conceive centres of force and lines of force 
 emanating from these centres. Though all visible effects 
 are perceived at the termination of the lines, his whole 
 attention was fixed on the space which was filled by them. 
 He objected to all materialistic conceptions and looked upon 
 an all-pervading medium which had been invented to explain 
 the phenomena of light as an unnecessary and objectionable 
 imagination. He insisted that the lines of force which 
 spread out from a centre cannot be conceived to be made of 
 different stuff from the centres themselves, and that, therefore, 
 the aether, if it exist at all, must itself be made up of lines of 
 force emanating from separate centres. We may, perhaps, 
 regard this view as a dim foreshadowing of the most recent and 
 not yet firmly established views which have emerged from 
 the so-called principle of relativity. The vibration of light 
 Faraday tentatively suggested to be due to a vibration of 
 the line of force emanating from a centre, and therefore 
 forming an essential part of it. Each particle of matter 
 in his mind sends out tentacles through space, and when 
 two bits of matter seem to act on each other at a distance 
 they only appear to do so because their tentacles are in- 
 visible to us. During the closing days of his fertile" life 
 
 r he planned experiments no doubt in connexion with his 
 -4 speculations on the nature of light to test whether magnetic 
 
 *- force requires time for its propagation. 
 
 Our belief in the conservation of energy now forms the 
 foundation of our conception of nature, and we hold to it 
 more firmly than to anything else that science has taught 
 us. All the changes we witness in the material world are 
 merely transformations of one form of energy into another, 
 and these different forms can all be measured in the same 
 units. The principle of conservation asserts that energy 
 
John Prescott Joule 23 
 
 is never lost or gained in any of these transformations, 
 the total quantity in the universe remaining the same. 
 The simplest kind of energy is that of a body in motion, 
 and is measured by half the product of the mass and the 
 square of the velocity. If a heavy body be allowed to drop 
 from a height, it increases its velocity as it falls, and strikes 
 the ground with a certain amount of energy. If that energy 
 has not been created, it must have existed already when 
 the body was placed at the height from which it fell. Hence 
 we must recognize some form of energy which depends on 
 the gravitational attraction between the earth and the 
 body. This potential energy, as we call it, is being trans- 
 formed into the energy of motion (kinetic energy) as the 
 body falls. These are the two great subdivisions of energy. 
 If heat be not a substance, as was generally believed till 
 the middle of last century, but a form of energy, a definite 
 quantity of heat should be equivalent to a definite amount 
 of energy ; so that whatever the means by which we trans- 
 form mechanical work into heat, we ought always to get 
 the same amount. That this conclusion is correct was esta- 
 blished by Joule's researches. It forms our first law of 
 thermodynamics . 
 
 John Prescott Joule 1 (1818-1889) began his scientific 
 career at the age of nineteen, and already six years later 
 he had established his position as one of the greatest 
 benefactors of the community. The characteristic quality 
 of mind which enabled him without aid and without en- 
 couragement to accomplish so much was his ability to fix 
 on the essential factors of a problem, and to verify his 
 ideas by accurate measurements. Inspiration came to him 
 from his own experiments; his first ideas were hesitating 
 and sometimes wrong, but correcting them step by step, he 
 was led almost automatically to the final great discovery. 
 His cautious and strictly scientific procedure showed itself 
 at an age when an abundance of energy and originality so 
 often lead to ambitious speculations which are beyond the 
 powers of inexperienced youth. Joule published his first 
 
 1 A valuable account of Joule's fife and work, by Osborne Reynolds, 
 will be found in the Joule volume of the Manchester Literary and 
 Philosophical Society. 
 
24 Britain's Heritage of Science 
 
 results in a series of letters addressed to Sturgeon's 
 " Annals of Electricity," and in the fourth of them he 
 gives us the guiding motive of his research. 
 
 " I can hardly doubt," he writes, " that electro- 
 magnetism will ultimately be substituted for steam to 
 propel machinery. If the power of the engine is in 
 proportion to the attractive force of its magnets, and 
 if this attraction is as the square of the electric force, 
 the economy will be in the direct ratio of the quantity 
 of electricity, and the cost of working the engine may 
 be reduced ad infinitum. It is, however, yet to be deter- 
 mined how far the effects of magnetic electricity may 
 disappoint these expectations." 
 
 Sturgeon's electro-magnetic engine which Joule tried to 
 improve was a very primitive machine. His first attempt 
 to render it more effective was not successful, as he admits ; 
 but what is remarkable is the strictly scientific manner in 
 which he measured the power by the weight the engine 
 could raise per minute. Joule next turned his attention 
 to the measurement of the electric power absorbed. He 
 designed and constructed a galvanometer for the purpose, 
 and as a first result discovered an important law (subse- 
 quently shown to be only approximately true), which appeared 
 to him to justify his belief in the future of the electro-magnetic 
 engine. The passage -quoted above in which he expresses 
 this belief shows, however, that consideration of the con- 
 servation of energy had not crossed his mind at that time, 
 and that he considered it possible to have an effective machine 
 the cost of working which may be reduced ad infinitum. 
 He had, nevertheless, some scruples about the effects of 
 " magnetic electricity," which may disappoint his expecta- 
 tions. He therefore directed his attention to these effects. 
 Referring to the impossibility of understanding experiments 
 made by different investigators, " which is partly due to 
 the arbitrary and vague numbers which are made to 
 characterize the electric current," he adopted a system of 
 units which can be reproduced anywhere, using the amount 
 of water decomposed per hour as the standard of current, 
 and the quantity of electricity delivered in one hour by the 
 unit current as the unit quantity. 
 
John Prescott Joule 25 
 
 In a paper " On the Production of Heat by Voltaic 
 Electricity," he announced the most important law, that 
 heat generated in a circuit is proportional to the time, the 
 resistance and the square of the current. 
 
 In the early stages of his investigations, Joule tacitly 
 adopted the then accepted view that heat is a substance, 
 which could not be generated or destroyed, but he soon 
 altered his opinion. In 1843 he expressed himself as 
 follows : 
 
 " The magnetic electrical machine enables us to 
 convert mechanical power into heat by means of the 
 electric currents which are induced by it. And I have 
 little doubt that, by interposing an electro -magnetic 
 engine in the circuit of a battery, a diminution of the 
 heat evolved per equivalent of chemical change would 
 be the consequence, and this in proportion to the 
 mechanical power obtained." 
 
 It seems that Joule was not then aware of the previous 
 experiments by Count Rumford, in which heat had been 
 generated by means of mechanical work (see page 108). 
 
 He assumed a more decisive attitude in a subsequent 
 paper, which is introduced with the words : 
 
 "It is pretty generally, I believe, taken for granted 
 that the electric forces which are put into play by the 
 magneto-electrical machine possess, throughout the whole 
 circuit, the same calorific properties as currents arising 
 from other sources. And indeed when we consider heat 
 not as a substance, but as a state of vibration, there appears 
 to be no reason why it should not be induced by an action 
 of a simply mechanical character, such, for instance, as 
 is presented in the revolution of a coil of wire before 
 the poles of a permanent magnet. At the same time, it 
 must be admitted that hitherto no experiments have 
 been made decisive of this very interesting question ; for 
 all of them refer to a particular part of the circuit only, 
 leaving it a matter of doubt whether the heat observed 
 was generated or merely transferred from the coils in which 
 the magneto -electricity was induced, the coils themselves 
 becoming cold. The latter view did not appear untenable 
 without further experiments. . . ," 
 
26 Britain's Heritage of Science 
 
 The crucial experiment was performed by Joule with the 
 result again in his own words " that we have therefore in 
 magneto-electricity an agent capable by simple mechanical 
 means of destroying or generating heat." The second part 
 of the same paper, entitled " On the Mechanical Value of 
 Heat," begins as follows : 
 
 " Having proved that heat is generated by the magneto- 
 electrical machine, and that by means of the inductive 
 power of magnetism we can diminish or increase at 
 pleasure the heat due to chemical changes, it became an 
 object of great interest to enquire whether a constant 
 ratio existed between it and the mechanical power gained 
 or lost. For this purpose it was only necessary to repeat 
 some of the previous experiments and to ascertain, at the 
 same time, the mechanical force necessary in order to 
 turn the apparatus." 
 He thus finds that 
 
 " The quantity of heat capable of increasing the 
 temperature of a pound of water by one degree of Fahren- 
 heit's scale is equal to, and may be converted into, a 
 mechanical force capable of raising 838 Ibs. to the 
 perpendicular height of one foot." 
 
 The particular method adopted to determine what we 
 now call the mechanical equivalent of heat was beset with 
 many experimental difficulties, and it is not therefore sur- 
 prising that his first result was nearly 9 per cent, in error. 
 Osborne Reynolds observed that the paragraph quoted really 
 overstates the conclusions Joule was entitled to draw, because 
 he has only shown that work could be converted into heat, 
 but not the inverse process, and that, at that time, he had 
 no clear ideas as to the conditions under which heat may be 
 converted into work. In fact he had dealt only with the 
 first law of thermodynamics, and it took some years before 
 the second law could be formulated with precision. It must 
 be remembered, however, that Joule was only twenty-five 
 years old at the time of his great discovery, and that he 
 was working alone, unsupported, and opposed by all the 
 prejudices of the recognized authorities. 
 
 It is not necessary to refer here in detail to the skill with 
 which Joule extended his investigations in many directions, 
 
John Prescott Joule 27 
 
 generating heat by mechanical force in different manners, 
 but always finding the same equivalent, until no vestige of 
 doubt was left that all different forms of energy could be 
 expressed in the same units. His measurements became 
 more and more accurate, and such uncertainties as remained 
 in the numerical value of the equivalent were, in great part, 
 due to the difficulty of measuring the temperature with a 
 glass thermometer ; the accuracy obtained was indeed to 
 some extent the result of the accidental excellence of his 
 thermometers. A few years later the composition of glass 
 became much less suitable for scientific use. 
 
 It has already been noted that while the conversion 
 of mechanical work into heat was completely and satis- 
 factorily dealt with by Joule, the converse transformation 
 of heat into work involves further important considerations, 
 into which it was necessary to enter. Sadi Carnot had, in 
 1824, published a work entitled " Reflexions sur la puis- 
 sance motrice du feu, et sur les machines propres a developper 
 cette puissance," in which the subject was treated with 
 masterly perspicuity, but his reasoning was expressed in 
 the language of the material theory of heat. He was, however, 
 the first to point out that the mechanical production of 
 an effect by a heat engine is always accompanied by a 
 transference of heat from one body to another at a lower 
 temperature. Relying on the axiom that a perpetual motion 
 involving a continuous performance of work is impossible, 
 he laid down the conditions for a thermodynamic engine 
 which, with a given transference of heat, would do the 
 maximum amount of work. The peculiarity of such an 
 engine is, that whatever amount of work can be derived 
 from a certain transference of heat, an equal reverse thermal 
 effect will be produced if the same amount of work be spent 
 in working it backwards. Further, the work done by a 
 perfect heat-engine must be the same for the same trans- 
 ference of heat, whatever be the nature of the material 
 used. If heat be a form of energy, and not a substance, 
 it is clear that the amount which enters the cooler body 
 of an engine must be less than that which leaves the 
 hotter one, and that the difference is equivalent to the 
 mechanical work done in the passage. The position of 
 
28 Britain's Heritage of Science 
 
 Joule was, therefore, necessarily antagonistic to Carnot's 
 assumption. 
 
 William Thomson (1824-1907), known to the present 
 generation as Lord Kelvin, while studying in Regnault's 
 laboratory in Paris, had become acquainted with the 
 important conclusions that may be drawn from Carnot's 
 thermodynamic cycle, and with the efforts which were being 
 made in France to verify the relations between the thermal 
 properties of substances which can be derived from it. 
 Though at first reluctant to abandon so fertile a principle, 
 and hesitating to give full assent to Joule's views, he soon 
 discovered that Carnot's reasoning may be modified so as to 
 bring it into harmony with the principle of the conservation 
 of energy. The same solution had occurred to Clausius, who, 
 anticipating Kelvin, was thus the first to give the correct 
 theory of the heat engine; but we are here concerned only 
 with the account of Kelvin's share in advancing the 
 subject; and a very magnificent share it was. His great 
 paper " On the Dynamical Theory of Heat," communicated 
 to the Royal Society of Edinburgh in 1851, places the whole 
 matter on a firm scientific basis, and establishes relations 
 between the physical properties of substances which have 
 all been verified experimentally. Full credit is given in 
 the paper to those who have contributed to, and, in part, 
 initiated, the ideas which led up to the final recognition 
 of the conservation of energy as the most fundamental 
 law of nature. What is called the second law of thermo- 
 dynamics is really the adaptation to thermodynamics 
 of the axiom expressing the impossibility of obtaining 
 a perpetual motion by a heat-engine. As formulated 
 by Lord Kelvin, it runs as follows : " It is impossible, 
 by means of inanimate material agency, to derive 
 mechanical effect from any portion of matter by cooling 
 it below the temperature of the coldest surrounding 
 objects." 
 
 Considerations leading up to a complementary principle 
 as important as that of the conservation of energy seem to 
 have been in Kelvin's mind at an early stage. If we imagine 
 a hot and a cold body, say, the boiler and condenser of a 
 steam engine, we may, by transferring the heat from the 
 
William Thomson 29 
 
 first to the second, transform part of the thermal energy 
 into work, but only a certain definite portion, exactly 
 calculable in accordance with the second law and Carnot's 
 principle. But if we bring the hot and cold bodies into 
 actual contact with each other, and allow the heat to pass 
 directly from one to the other, without doing mechanical 
 work, their temperature will be equalized, and we shall have 
 lost for ever the possibility of utilizing the thermal energy 
 which has been transferred. There is, therefore, a funda- 
 mental difference between the transformation of mechanical 
 work into heat and the inverse transformation. In the 
 former case we may convert the whole mechanical energy 
 into heat, as when we rub two bodies together and raise 
 their temperature through friction, while, in the reverse 
 operation, when heat is transformed into work, only part 
 of that which leaves the source of heat is utilized. We must 
 therefore distinguish in the energy of a body a part which 
 is available for the performance of useful work, and another 
 part which is unavailable, the thermal energy of a body 
 containing only a definite proportion belonging to the first 
 category. Moreover, it is only the ideally perfect engine 
 that can utilize the whole of the available energy; in 
 machines such as those we can construct there is always a 
 further loss due to their imperfection. We must conclude 
 that in the constantly occurring processe3 in which heat is 
 allowed to pass from one piece of matter to another without 
 doing useful work, the quantity of available energy stored 
 in the universe is diminished. This leads us to the counter- 
 part of the principle of conservation, which is that of the 
 dissipation of energy. Among the wealth of achievements 
 contained in the intellectual heritage left us by Kelvin, 
 the discovery of this truth is pre-eminently the one which 
 stands out as a landmark to future generations. It was 
 first announced in 1852, and we may quote the main 
 conclusions as then formulated. 
 
 1. There is at present in the material world a universal 
 tendency to the dissipation of mechanical energy. 
 
 2. Any restoration of mechanical energy, without more 
 than an equivalent dissipation, is impossible in inanimate 
 material processes, and is probably never effected by means 
 
30 Britain's Heritage of Science 
 
 of organized matter, either endowed with vegetable life, or 
 subject to the will of an animated creature. 
 
 3. Within a finite period of time past, the Earth must 
 have been, and within a finite period to come the Earth must 
 again be. unfit for the habitation of man as at present 
 constituted, unless operations have been, or are to be, 
 performed, which are impossible under the laws to which 
 the known operations going on at present in the material 
 world are subject. 
 
 The third of these statements must necessarily apply 
 not only to this earth but to the whole universe, and there 
 is therefore no escape from the conclusion that the material 
 universe, as we know it, is like a clockwork which is slowly 
 but steadily running down. 
 
 It was reserved to Clerk Maxwell to perceive the reason 
 of our inability to check the gradual degradation of energy. 
 Heat is essentially a disorderly motion, the particles of 
 matter in a body which is apparently at rest moving 
 irregularly in all directions. We are unable to convert this 
 irregular into a regular motion, and it is this limitation of 
 our powers which prevents our making full use of molecular 
 energy as a source of mechanical work. Speaking of the 
 second law of thermodynamics, Maxwell says : . . . . 
 " it is undoubtedly true, as long as we can deal with bodies 
 only in mass, and have no power of perceiving or handling 
 the separate molecules of which they are made up. But 
 if we conceive a being whose faculties are so sharpened that 
 he can follow every molecule in its course, such a being, 
 whose attributes are still as essentially finite as our own, 
 would be able to do what is at present impossible to us. 
 For we have seen that the molecules in a vessel full of air 
 at uniform temperature are moving with velocities by no 
 means uniform, though the mean velocity of any great 
 number of them, arbitrarily selected, is almost exactly 
 uniform. Now let us suppose that such a vessel is divided 
 into two portions, A and B, by a division in which there is 
 a small hole, and that a being, who can see the individual 
 molecules, opens and closes this hole so as to allow only 
 the swifter molecules to pass from A to B, and only the 
 slower ones to pass from B to A. He will thus, without 
 
Clerk Maxwell 31 
 
 expenditure of work, raise the temperature of B and lower 
 that of A, in contradiction to the second law of thermo- 
 dynamics." 
 
 In the history of electrical science Maxwell (1831-1879) 
 stands in very much the same relative position to Faraday 
 as Lord Kelvin occupied towards Joule in the domain of 
 heat. They both brought pre-eminently mathematical minds 
 to bear on the results of experimental discoveries, and saw 
 more clearly than the original discoverers the important 
 consequences which flowed from their researches. Neither 
 Faraday nor Joule were experimentalists pure and simple, 
 they were indeed guided mainly by theoretical considera- 
 tions; but it lay beyond their object or powers to enter 
 fully into the wider generalizations, though Faraday showed 
 in the passages we have quoted that his imagination went 
 far beyond his immediate experimental results. 
 
 The theory of electrostatics which deals with electric 
 charges at rest, their distribution on conductors, and their 
 mutual attractions or repulsions, is explained in the simplest 
 manner by assuming the existence of two kinds of electricity, 
 for which it is convenient to retain the old names, positive 
 and negative electricity. The mechanical effects of the 
 charges may be dealt with mathematically very much as 
 we do in the case of gravitational attractions. There is 
 also a formal analogy between magnetic and electric actions, 
 so that independent magnetic fluids were sometimes intro- 
 duced to facilitate the treatment of magnetic problems. 
 
 Faraday saw that, if we wish to grasp the relationship 
 between the action of electric charges at rest and the electro- 
 dynamic effects produced by electricity in motion, and 
 more especially, if we wish to include in the same field of 
 enquiry the electric effects produced by moving magnets, 
 we must take a more comprehensive view. We must cease 
 to look at the centres or origin of the forces, and fix our 
 attention on the medium between them. This, as has already 
 been explained, was Faraday's outlook. Further, if the 
 effects of light and electricity are both transmitted through 
 a medium, our natural distaste to add unnecessarily to 
 the number of hypotheses inclines us to the belief that the 
 same medium serves bo:h purposes. But here a formidable 
 
32 Britain's Heritage of Science 
 
 difficulty presented itself. The phenomena of light seemed 
 to be explained in a satisfactory manner by giving to the 
 aether the properties of ordinary incompressible elastic 
 bodies, though certain circumstances might have roused the 
 suspicion that we had not got hold of the whole truth. Yet 
 the essential points seemed so well accounted for by the 
 investigations of Green and Stokes, that there was every 
 reason to believe that outstanding difficulties would be 
 satisfactorily solved, without abandoning the substance of 
 the theory. It was quite clear, nevertheless, that the medium 
 invented to explain the properties of light, 'could not account 
 for the electrical effects. 
 
 It is here that Maxwell's genius saw the solution : the 
 problem had to be inverted. It was not the question of 
 whether a medium adapted to account for the comparatively 
 simple phenomena of light could explain electrical action, 
 but whether a medium constructed so as to explain electrical 
 action could also explain the phenomena of light. In 
 formulating the essential properties of the medium which 
 could produce the electrical effects, Maxwell had to fit a 
 mathematical mantle on the somewhat crude skeleton of 
 Faraday's creation. The task was formidable, and the 
 manner in which it was carried through stands unequalled 
 by any achievement in the whole range of scientific history, 
 both as regards its intellectual effort and its final results. 
 Only one of its successes need here be recorded. A quantity 
 of electricity may be measured either by its electrostatic, 
 when it is at rest, or by its electrodynamic effect, when it 
 is in motion. Looking separately at the two manifestations 
 of electricity, we are led to two different units in which it 
 can be measured, the so-called electrostatic and electro- 
 magnetic units. The time of propagation of an electro- 
 dynamic effect through space was proved by Maxwell to be 
 equal to the ratio of these two units. It could be calculated, 
 therefore, from purely electric measurements, and it turned 
 out to be exactly equal to the velocity of light. Hence 
 luminous and electrodynamic disturbances are propagated 
 with the same velocity, and we must conclude that their 
 nature is identical. There was, after the publication of 
 Maxwell's work, really nothing more to be said for the older 
 
Michael Faraday 
 
 From a painting by A. Blakeley, in 
 
 the. fonKSPSKinn ni the. 7?mvi/ Snrietv* 
 
Clerk Maxwell 33 
 
 view which gave to the aether the properties of elastic 
 solids. 
 
 Brought up in a school of physicists which based the 
 explanation of natural phenomena on perfectly defined 
 conceptions, and required, therefore, always a mechanical 
 model to represent properties of matter and force, Maxwell 
 in his first efforts tried to outline the mechanical construction 
 of the aether necessary to explain the electrical effects. He 
 conceived this aether, the ultimate elements of which retained 
 the properties of the cruder forms of matter, to be composed 
 of cells, each of which enclosed a gyrostatic nucleus. 
 Gradually, however, he abandoned these attempts at finding 
 a mechanical model for the aether, and was satisfied to rely 
 mainly on the mathematical formulae which expressed its 
 properties in the simplest way. In this he followed, or, to 
 be strictly accurate, helped to initiate, the modern tendency 
 of refusing to go beyond the immediate results of observa- 
 tion, relegating tacitly all questions of interpretation to the 
 domain of metaphysics; which means disregarding them 
 altogether. Maxwell's electrical work has revolutionized the 
 whole aspect of science ; and though undertaken in the purest 
 spirit of philosophic enquiry, it has led directly to the great 
 practical results which we see in the present applications of 
 wireless telegraphy. 
 
 It is seldom that it is given to one man to open out new 
 paths of thought in more than one direction. Newton's 
 theory of gravitation and his optical work is an example 
 of such a rare success, and there is perhaps no other equally 
 marked except that supplied by Maxwell. Though his 
 work on the constitution of gases may not have been as 
 far-reaching in its results as the monumental researches we 
 have already noted, it has introduced a new and original 
 idea into the treatment of the properties of matter. 
 
 Towards the middle of last century, Herapath had 
 revived the theory originally proposed by Daniel Bernoulli, 
 according to which the pressure of a gas is due to the impact 
 of its molecules against the sides of the vessel which contains 
 it, and Joule, adopting this view, had calculated the velocity of 
 the molecules of a gas from its known density and pressure. 
 Such calculations can only give us the measure of an 
 
 C 
 
34 Britain's Heritage of Science 
 
 average. Through mutual collisions or otherwise, each 
 particle constantly changes its velocity both in magnitude 
 and direction, and it becomes important to determine the 
 law regulating the distribution of velocities. Maxwell's 
 classical investigation of this difficult problem has since 
 been modified in detail and extended, but the manner in 
 which he attacked it introduced an entirely novel method of 
 applying mathematical reasoning to physical phenomena. 
 Its results were decisive, and led to the discovery of new 
 experimental facts connected with the internal friction of 
 gases. When a metal disc is suspended from a wire passing 
 through its centre so that the plane of the disc is horizontal, 
 a twist imposed on the wire will cause the disc to perform 
 oscillations in its own plane, which diminish in magnitude 
 and gradually disappear owing to the internal friction of 
 the gas surrounding it. Maxwell's calculations led to the 
 unexpected result that this retarding effect should be the 
 same whatever the pressure of the gas, so that air at a 
 pressure of a few millimetres should diminish the motion of 
 the disc as rapidly as when it is at atmospheric pressure. 
 This surprising result was tested experimentally and found 
 to be correct. 
 
 We are naturally interested in the personal history of 
 those who have initiated new departures in science, and it 
 is more especially instructive to record the character of their 
 early education and the conditions under which they accom- 
 plished their work. Without entering into biographical 
 details, we may briefly state, so far as they have not already 
 been given, the essential facts in the lives of the great men 
 whose achievements have formed the subject of this chapter. 
 
 Isaac Newton, the posthumous son of a small freehold 
 farmer in Lincolnshire, is reported to have been like Kepler 
 a seven months' child. While attending school at Grantham, 
 he showed little disposition towards book learning, but 
 great aptitude for mechanical contrivances, and he amused 
 himself with the construction of windmills, water clocks, and 
 kites. Not being considered fit to be a farmer, he was 
 sent to the University of Cambridge in 1661, on the recom- 
 mendation oi an uncle who was a graduate of Trinity College. 
 He does not seem to have received much inspiration from 
 
Clerk Maxwell, Isaac Newton 35 
 
 his teachers, but pursued his reading according to his own 
 choice, and it was Descartes' " Geometry " that inspired 
 his love for mathematics. In 1665, at the age of twenty-five, 
 he left Cambridge on account of the Plague, and it seems 
 that in this year the method of " fluxions," which contains 
 the germ of the differential calculus, first occurred to him. 
 Returning to Cambridge, he began his optical and chemical 
 experiments, and continued his mathematical researches at 
 the same time. In the year 1669, he was elected Lucasian 
 Professor of Mathematics, and chose Optics as the subject 
 of his first series of lectures. He continued his studies at 
 Cambridge, the " Principia " being published in 1687. As 
 a sign of national gratitude, Montague (afterwards Earl of 
 Halifax), then Chancellor of the Exchequer and at the same 
 time President of the Royal Society (1695-1698), offered 
 Newton the post of Warden of the Mint in 1695, and this 
 was followed five years later by his appointment to the 
 Mastership, which was then worth between 1,200 and 
 1,500 per annum. Newton continued, however, to dis- 
 charge his professorial duties at Cambridge until 1701. 
 From 1703 onwards until his death, twenty-five years later, 
 he held the Presidency of the Royal Society. 
 
 One is tempted to look upon the quiet life of the old 
 Universities as being specially conducive to study and 
 research, but the times of active progress in the Universities 
 coincided rather with the periods when political disturbances 
 were sufficiently intense to penetrate these havens of rest. 
 Such a time was the end of the seventeenth century, when 
 the interference of James II. into University affairs was a 
 source of trouble both at Oxford and Cambridge. Newton 
 himself took an active part in defending the prerogatives 
 of the University. On a previous occasion he had taken the 
 side of the Senate against the Heads of Colleges in a dispute 
 about the Public Oratorship, and when in 1687 the King 
 issued a mandate that a certain Benedictine monk should 
 be admitted a Master of Arts without taking the oaths of 
 allegiance and supremacy, Newton was one of the deputies 
 appointed by the Senate to make representations to the 
 High Commissioners' Court at Westminster. 
 
 In recognition of the services rendered to the University, 
 
 C2 
 
36 Britain's Heritage of Science 
 
 he was elected on two occasions as their representative in 
 Parliament. The interest which Newton displayed in 
 University politics illustrates his intellectual vigour, and 
 is inseparable from those qualities to which he owes his 
 commanding position in the history of science. While it is, 
 therefore, useless to speculate whether he was wise to allow 
 his attention to be diverted from his more serious work, 
 it is much to be regretted that his mind should have been 
 disturbed by discussions about priority which affected his 
 nervous system and damaged his health. These discussions 
 were forced upon him, and he would gladly have avoided 
 the bitter controversies with Hooke and, in later years, 
 with Leibnitz. 
 
 No two men could differ more in temperament or outlook 
 than Newton and John Dalton. To Newton the accurate 
 numerical agreement between the results of observation 
 and those of theory was of paramount importance, while 
 in Dalton's experiments, numerical results were mainly used 
 as illustrations of a theory which to him did not admit of 
 any doubt. John Dalton was the second son of a weaver 
 in poor circumstances living in Cumberland. In 1778, 
 when only twelve years old, he started teaching at the 
 Quaker School in Eaglesfield, where he himself had obtained 
 his first instruction. In this he was not successful, and 
 after a brief attempt at earning his living as a farmer, he 
 left his native village In 1781, in order to assist a cousin who 
 kept a school at Kendal. In 1793 he moved to Manchester, 
 where he spent the remainder of his life as a teacher of 
 mathematics and natural philosophy, first in " New College " 
 (which ultimately was transferred to Oxford as " Manchester 
 College "), and later privately. As early as 1787 he began 
 to keep a meteorological diary, which he continued to the 
 time of his death fifty-seven years later. He led the quiet 
 life of a student, interrupted by occasional visits to the 
 Lake District. In 1822 Dalton paid a short visit to Paris; 
 of London he remarked that it was " the most disagreeable 
 place on earth, for one of a contemplative turn, to reside in 
 constantly " In addition to the work which gained him 
 immortality, he foreshadowed several subsequent discoveries, 
 and enunciated the correct law of expansion of gases some 
 
John Dalton, Thomas Young 37 
 
 months before Gay Lussac, without, however, ever giving 
 the numerical measurements required to prove the law. 
 He was affected by colour-blindness, and first examined that 
 defect scientifically. Dalton died in 1844, being then 
 seventy-eight years old. 
 
 Thomas Young was probably, next to Leonardo da 
 Vinci, the most versatile genius in history. He was 
 descended from a Quaker family of Milverton, Somerset, and 
 at the age of fourteen was acquainted with Latin, Greek, 
 French, Italian, Hebrew, Persian and Arabic. He studied 
 medicine in London, Edinburgh and Gottingen, and subse- 
 quently entered Emmanuel College, Cambridge. In 1799, 
 at the age of twenty-six, he established himself as a physi- 
 cian in London. Subsequently he held for two years the 
 Professorship of Physics at the Royal Institution, but 
 resigned, fearing that his duties might interfere with his 
 medical practice ; during the tenure of his Professorship he 
 delivered many lectures, which were subsequently published, 
 and contain numerous anticipations of later theories. In 
 1804 he was elected Foreign Secretary of the Royal Society, 
 and held that position for twenty-six years. In 1811 
 he became physician to St. George's Hospital, and Super- 
 intendent of the Nautical Almanac. His efforts to decipher 
 Egyptian hieroglyphic inscriptions were among the first that 
 were attended with success. His share in establishing the 
 undulatory theory of light has already been described, and his 
 claims as the founder of physiological optics will be discussed 
 in another chapter (p. 299). Thomas Young was a man 
 of private means, and not dependent on his medical practice 
 for a living. He died in London in the year 1829. To 
 quote Helmholtz : 
 
 " He was one of the most clear-sighted of men who 
 ever lived, but he had the misfortune to be too greatly 
 superior in sagacity to his contemporaries. They gazed 
 at him in astonishment, but could not always follow the 
 bold flights of his intellect." 
 
 Michael Faraday, the son of a working blacksmith, was 
 brought up in humble circumstances, and had but a 
 scanty school education. In 1804, at the age of thirteen, 
 he became an errand boy to a bookseller and stationer in 
 
38 Britain's Heritage of Science 
 
 London, part of his duties being to carry round the news- 
 papers in the morning. After a year of probation he was 
 formally apprenticed to learn the art of bookbinding. It 
 was by reading some of the books that passed through his 
 hands that his mind was first attracted to science. Noticing 
 an advertisement in the streets announcing evening lectures 
 in Natural Philosophy with an admission fee of one shilling, 
 he obtained his master's permission to attend the lectures. 
 The account of his first connexion with the Royal Institution 
 may be given in his own words : 
 
 " When I was a bookseller's apprentice I was very 
 fond of experiment and very averse to trade. It 
 happened that a gentleman, a member of the Royal 
 Institution, took me to hear some of Sir H. Davy's 
 lectures in Albemarle Street. I took notes, and afterwards 
 wrote them out more fairly in a quarto volume. 
 
 " My desire to escape from Trade, which I thought 
 vicious and selfish, and to enter into the service of Science, 
 which I imagined made its pursuers amiable and liberal, 
 induced me at last to take the bold and simple step of writing 
 to Sir H. Davy, expressing my wishes, and a hope that, 
 if an opportunity came in his way, he would favour 
 my views ; at the same time, I sent the notes I had taken 
 of his lectures. . . . This took place at the end of 
 the year 1812, and early in 1813 he requested to see me, 
 and told me of the situation of assistant in the laboratory 
 of the Royal Institution, just then vacant. 
 
 " At the same time that he thus gratified my desires 
 as to scientific employment, he still advised me not to 
 give up the prospects I had before me, telling me that 
 Science was a harsh mistress ; and in a pecuniary point 
 of view but poorly rewarding those who devoted them- 
 selves to her service. He smiled at my notion of the 
 superior moral feelings of philosophic men, and said he 
 would leave me to the experience of a few years to set 
 me right on that matter. 
 
 " Finally, through his good efforts, I went to the 
 Royal Institution early in March of 1813 as assistant 
 in the laboratory ; and in October of the same year went 
 with him abroad as his assistant in experiments and 
 
Michael Faraday 39 
 
 writing. I returned with him in April 1815, resumed 
 my studies in the Royal Institution, and have, as you 
 know, ever since remained there." 
 
 The journey abroad was a great event in Faraday's 
 life, as he became acquainted with many famous men of 
 science. Unfortunately his position was an unpleasant 
 one. At the last moment, Sir Humphry Davy's valet had 
 refused to leave the country, and Faraday had undertaken 
 to replace him until he could engage a substitute at Paris; 
 but no suitable person being found there, Faraday had to 
 continue in the menial work which did not form part of 
 the duties for which he was engaged. " I should have 
 little to complain of," wrote Faraday, in connexion with 
 this matter, " were I travelling with Sir Humphry alone, 
 or were Lady Davy like him." An interesting incident 
 took place during their stay at Geneva in the summer of 
 1814. During a shooting expedition, Faraday accompanied 
 the party in order to load Davy's gun, and De La Rive, 
 their host, accidentally entering into conversation with 
 him, found that the boy who had been dining with his 
 domestics was an intelligent man of science; accordingly 
 he invited Faraday to dine at his table. To this Lady 
 Davy strongly objected, and matters had to be compro- 
 mised by dinner being served for Faraday in a separate 
 room. 
 
 On his return home, after an absence of eighteen months, 
 Faraday was again engaged as an assistant at the Royal 
 Institution, and obtained some practice in lecturing at the 
 " City Philosophical Society." His independent scientific 
 work began in 1816, and was continued without interruption 
 until 1860. In 1827 Mr. Brande, who had succeeded Davy 
 as Professor of Chemistry at the Royal Institution, resigned 
 his position and Faraday was elected in his place, having 
 already, since 1825, occupied the position of Director of the 
 Laboratory. Faraday's emoluments were insufficient even 
 for his modest requirements, so that he had to supplement 
 them by undertaking private practice in chemical analysis 
 and expert work in the law courts; but though the income 
 which he thus secured was very substantial, he soon gave 
 it up, as he found it interfered with his scientific work. 
 
40 Britain's Heritage of Science 
 
 In its place he accepted a lectureship at the Royal Academy 
 of Woolwich with a salary of 200. Subsequently, he was 
 made scientific adviser to Trinity House. At a later period 
 he was granted a Civil List pension of 300. Unselfish, 
 high-minded, and modest, Faraday enjoyed the confidence 
 of his friends, and declined all official honours. His out- 
 standing quality was his irrepressible enthusiasm for experi- 
 mental research. Foreign visitors to the laboratory relate 
 how, after a demonstration of one or other of his 
 discoveries, " his eyes lit up with fire," or how, when in 
 their turn, they showed him a striking experiment, he 
 danced around, and wished he could always live " under 
 the arches of light he had witnessed." Though interested 
 in all practical applications of science, he preferred to leave 
 their development to others. 
 
 " I have rather," he is reported to have said, " been 
 
 desirous of discovering new facts and new relations 
 
 dependent on magnetoelectric induction than of exalting 
 
 the force of those already obtained; being assured that 
 
 the latter would find their full development hereafter." 
 
 The importance of the electrical industries to-day prove 
 
 how brilliantly this assurance has been justified. 
 
 Joule's name appears to be derived from " Youlgrave," 
 a village in Derbyshire where his family originally resided; 
 but his grandfather migrated to Salford and acquired wealth 
 as a brewer. When Joule was ten years old, his father 
 sent him, together with his elder brother, to study chemistry 
 under Dalton, who, however, during two years confined 
 his instruction entirely to elementary mathematics, and 
 before they could proceed to chemistry, Dalton was struck by 
 paralysis, and had to give up work. It has already been 
 explained how Joule was led to his final discoveries, starting 
 from the desire to utilize the power of electrodynamic 
 machines, which were then not more than interesting toys. 
 Towards the end of 1840, when Joule was only twenty -two 
 years of age, he forwarded a paper to the Royal Society 
 in which he announced the correct law indicating how the heat 
 developed in a wire through which a current of electricity 
 passes depends on the intensity of the current. That paper 
 was published in abstract in the Proceedings of the Royal 
 
John Prescott Joule 41 
 
 Society, but full publication in the Transactions was 
 declined. A worse fate befell a later paper : "On the 
 Changes of Temperature produced by the Rarefaction and 
 Condensation of Air," read on June 20th, 1844, but not 
 printed by the Society even in abstract. Joule must 
 have felt severely disappointed at the time, but his dis- 
 position was so amiable and indulgent to human failings 
 that, at any rate in his later years, he did not show any 
 resentment. "I can quite understand," he once remarked, 
 " how it came about that the authorities of the Royal 
 Society refused my papers. They lived in London ; I lived 
 in Manchester ; and they naturally said : What good can 
 come out of a town where they dine in the middle of the 
 day ? " 
 
 Joule had not, however, to wait long for recognition; 
 he was elected a Fellow of the Royal Society in 1850, a year 
 before the same honour fell to Lord Kelvin and Stokes. 
 The turning point in his life came with the meeting of the 
 British Association at Oxford in June 1847, where he 
 described his experiments. According to Joule's account 
 that communication would have passed without comment 
 if a young man had not risen, and by his intelligent observa- 
 tions created a lively interest in the new theory of heat. 
 That man was William Thomson, afterwards Lord Kelvin, 
 whose recollection of the meeting differs, however, from that 
 of Joule. 
 
 " I heard," he writes some years later, " his paper 
 read at the sections, and felt strongly impelled to rise 
 
 and say that it must be wrong but as 
 
 I listened on and on, I saw that Joule has certainly a 
 great truth and a great discovery and a most important 
 measurement to bring forward. So, instead of rising 
 with my objection to the meeting, I waited till it was 
 over, and said my say to Joule himself at the end of 
 the meeting." 
 
 Whichever version of the incident be the correct one, 
 it led to a lifelong friendship, and marks the date at which 
 opposition to Joule's views began to break down. Faraday 
 was also present at the meeting, and was impressed by 
 Joule's work, 
 
42 Britain's Heritage of Science 
 
 On the whole, Joule's life ran a smooth course. The 
 independent means of his father allowed him to devote 
 his whole time to scientific researches. He never took an 
 active share in the management of the brewery, but the 
 record of his observations of the pressure and temperature 
 of the air are often entered on the blank pages of the books 
 in which the stocks of barrels were kept. After his father's 
 death, unfortunate investments materially diminished his 
 income, and he was unable to undertake the heavy 
 expenditure involved in the prosecution of his researches 
 without some assistance from scientific societies with 
 funds available for research purposes. The grant of a 
 pension of 200 from the Civil List released him in 1878 
 from further anxieties. In private life Joule often 
 expressed his opinions strongly, but the kindness of his 
 character impressed all who came into contact with him, 
 and the modesty of the man who, as much as any one, 
 has placed experimental science in this country in the 
 commanding position it occupies, is typically illustrated 
 by the remark he made about himself two years before 
 his death : "I believe I have done two or three little things, 
 but nothing to make a fuss about." 
 
 William Thomson, born in 1824, was the second son of 
 James Thomson, who, at the time of his marriage, was 
 Professor of Mathematics in the " Academical Institution," 
 Belfast. He was eight years old when his father took over 
 the Professorship in the same subject at the University of 
 Glasgow, and matriculated at that University at the early 
 age of ten. He entered as an undergraduate at Cambridge 
 in October, 1841, his first paper " On Fourier's Expansions 
 of Functions in Trigonometrical Series " having already been 
 published in the Cambridge Mathematical Journal in May 
 of the same year. The paper was apparently written during 
 a journey to Germany in the previous summer. No less 
 than thirteen additional papers were published by him in 
 the same journal during his undergraduate career, which 
 ended in 1845 with his graduation as second wrangler. In 
 the following year he was appointed Professor of Natural 
 Philosophy at Glasgow, a position which he held during 
 fifty-four years. From an early period he was recognized 
 
John Prescott Joule, Lord Kelvin 43 
 
 as one of the greatest scientific intellects of his time, sur- 
 passed in power by none, in originality perhaps only by 
 Maxwell. Well merited honours came to him in rapid 
 succession. He was created a knight in 1866, General 
 Commander of the Victorian Order in 1896, and a Peer of 
 Great Britain as Lord Kelvin in 1892. The Royal Society 
 awarded to him the Copley Medal their highest distinc- 
 tion in 1883, and he occupied their Presidential Chair 
 between 1890 and 1895. He was one of the original members 
 of the Order of Merit, which was founded in 1902, and in 
 the same year was made a Privy Councillor. He was buried 
 in Westminster Abbey by the side of Newton. 
 
 Lord Kelvin's powers of work were prodigious and his 
 memory unequalled. He claimed to be able to take up at 
 any time the thread of an investigation which he had left 
 unfinished ten years previously. His brain was uninterruptedly 
 active ; his notebook handy on every railway journey, and 
 he could work till the late hours of an evening without 
 risking a sleepless night. 
 
 Everyone interested in the history of science must often 
 have asked himself the question how far its progress would 
 have been retarded if a particular brain had never been 
 called into existence. With few exceptions the answer 
 arrived at would be that, though discoveries might have- 
 been delayed and reached by different roads, and the work 
 of one man divided between two and three, the effect in the 
 long run would have been small and perhaps insignificant ; 
 but it is difficult to believe that science would stand where 
 it does to-day if Maxwell had never lived. Faraday's way 
 of looking at things was perhaps equally distinctive, but 
 Faraday's originality lay in the manner in which he was 
 led to perform the experiments which brought new facts 
 to light, and the same experiments might have suggested 
 themselves to others in a different manner. Maxwell's 
 originality of thought, on the other hand, was the essential 
 factor in the investigation, and it is almost impossible to see 
 how his results could have been arrived at by a different 
 road from that which he took. He also possessed another 
 power not always given to great intellects. A mind that 
 excels in originality is frequently unable or, at any rate, 
 
44 Britain's Heritage of Science 
 
 unwilling to follow other men's lines of reasoning, and 
 thereby loses much of its power of fructifying contemporary 
 thought. But in Maxwell it was not only his originality, 
 but also his receptivity that was exceptional. No one was 
 less imitative, either in the manner of expression or in the 
 direction of his thoughts ; but he always knew how his own 
 way of looking at things was related to that of others. 
 
 We possess a good account of Maxwell's life, 1 rendered 
 specially valuable by the number of his letters which are 
 reproduced; these allow us to get a glimpse of the 
 attractive quaintness with which he could illuminate every 
 subject, but the barest outline of his career must here 
 suffice. 
 
 His powers of observation showed themselves at a very 
 early age. In a letter, written when he was not yet three 
 years old, his mother relates that " Show me how it does " 
 was never out of his mouth, and that he investigated the 
 hidden courses of streams and bell wires. At school, he did 
 not at first take a very high place, and his schoolfellows 
 so much misunderstood the character of the reserved, 
 dreamy boy, that they gave him the nickname of " Dafty." 
 He soon, however, grew interested in his work, and ah 1 his 
 letters home breathe a healthy playful spirit. When fourteen 
 years old he was taken by his father to attend some of the 
 meetings of the Royal Society of Edinburgh, and a year 
 later wrote a paper " On the Description of Oval Curves," 
 which, on the recommendation of Professors Kelland and 
 Forbes, was published by that Society. At that time he 
 was already repeating for his own instruction experiments 
 on light and magnetism. He entered the University of Edin- 
 burgh in 1847 at the age of sixteen, and after remaining three 
 years entered Peterhouse at Cambridge, from which college, 
 however, he soon migrated to Trinity, graduating as second 
 wrangler in 1854. While still an undergraduate he pub- 
 lished a number of papers in the Cambridge and Dublin 
 Mathematical Journal ; from that time onwards his scientific 
 activity never ceased and gradually spread over a wider 
 and wider range of subjects. 
 
 1 "Life of James Clerk Maxwell,' 5 by Lewis Campbell and William 
 Garnett (Macmillan, 1882), 
 
Clerk Maxwell 45 
 
 In November 1856 Maxwell was appointed Professor of 
 Natural Philosophy at Marischal College, Aberdeen, a chair 
 which was abolished in 1860 in consequence of the fusion 
 of the two colleges in tha town. Among many characteristic 
 remarks which occur in his letters of that period we may 
 quote the following : "I found it useful at Aberdeen to tell 
 the students what parts of the subject they were not to 
 remember, but to get up and forget at once as being rudi- 
 mentary notions necessary to development, but requiring 
 to be sloughed off before maturity." Between 1860 and 
 1865 Clerk Maxwell taught Physics at King's College, 
 London. His duties there were exacting and he suffered 
 from two serious illnesses. He may have realized that his 
 powers of teaching did not lie in the direction of making 
 matters easy to students, many of whom were not over 
 anxious to learn, but it was probably mainly for reasons 
 of health that he resigned his chair and settled down at 
 Glenlair, the house built by his father on the family estate 
 in Dumfriesshire. A few years later he was, however, 
 persuaded with some difficulty to take over the newly- 
 established Professorship of Experimental Physics at Cam- 
 bridge. The Cavendish Laboratory was built in that 
 University by the Vllth Duke of Devonshire for the pro- 
 secution of experimental research in Physics ; it was opened 
 in 1870, and there probably never has been a benefaction 
 more fruitful in its results. The laboratory has, indeed, had 
 a brilliant history ; its immediate result was to allow Clerk 
 Maxwell to spend the closing years of his life among old 
 friends and new pupils. He died after a short but painful 
 illness in November 1879, at the age of forty-eight. Those 
 who knew him will hold his memory in affectionate remem- 
 brance, and to all who turn to his writings for a knowledge 
 of his work he will always remain a source of inspiration. 
 
46 Britain's Heritage of Science 
 
 CHAPTER II 
 
 (Physical Science) 
 
 THE HERITAGE OF THE UNIVERSITIES 
 during the Seventeenth and Eighteenth Centuries 
 
 THE range of activity covered by University teaching 
 in the sixteenth century is indicated by the subjects 
 assigned to the five Regius Professorships founded in 1546 
 at Oxford and Cambridge by King Henry VIII. These 
 were Divinity, Hebrew, Greek, Civil Law, and Medicine, 
 the latter subject forming the only point of contact with 
 science. The practical demands of navigation were, how- 
 ever, beginning to stimulate the study of mathematics and 
 astronomy, and when Gresham College was founded in 1575, 
 separate professorships in these subjects were provided for. 
 A few years later (1583), Edinburgh appointed professors 
 of mathematics and natural philosophy, and Oxford followed 
 with the endowment of the Sedleian Professorship of Natural 
 Philosophy (1621), the Savilian Professorship of Geo- 
 metry (1619), the Savilian Professorship of Astronomy 
 (1621), and a Professorship of Botany (1669). During the 
 seventeenth century, Cambridge could only claim the 
 Lucasian Chair of Mathematics (1663), but it was the first 
 University with a Chair of Chemistry, endowed in 1702. 
 Its two Professorships of Astronomy were founded in 1704 
 and 1749 respectively. Chemistry and Botany being mainly 
 introduced as adjuncts to medicine, it appears that science 
 at the Universities may be said to have been confined to 
 the application of mathematics first to Astronomy, and 
 subsequently to other subjects, which, as they became more 
 definite began to supply material for* the exercise of mathe- 
 matical skill. Experimental science for its own sake began 
 to be taught at the Universities only in comparatively recent 
 
Gresham College 47 
 
 times. On the other hand, it is well to dispose at once of 
 the erroneous impression that the British Universities were 
 bodies which confined themselves to the academic discussion 
 of abstruse subjects unrelated to the ordinary interests of the 
 community. The Universities trained the medical men. 
 who kept the flag of science flying in the eighteenth century, 
 and the study of astronomy was pursued in great part for 
 the sake of its value in finding the position of ships at sea, 
 and in the measurement of time. The problems dealt with 
 by mathematicians were, at first, generally suggested by 
 practical requirements, and only gradually became detached 
 from them. In fact, science began to be taught as a means 
 towards a practical end. 
 
 If Gresham College had developed as it ought to have 
 done into a University of London, it might have affected 
 the higher education of England at a critical time in a 
 manner which it is difficult now to estimate. Its founder, 
 Sir Thomas Gresham, had studied at Cambridge, and was 
 a man of exceptional abilities. He was admitted to the 
 Mercers' Company at the age of twenty-four, and soon 
 afterwards went to the Netherlands, where his father, a 
 leading London merchant, had business interests. By his 
 management of affairs in Amsterdam he helped King 
 Edward VI. over his private financial difficulties, and 
 received valuable grants of land as a reward. Under Queen 
 Elizabeth he continued to act as financial agent of the 
 Crown, and was knighted previous to his departure on a 
 mission to the Count of Parma. Having realized the utility 
 of the " Bourse " of Amsterdam during his residence in 
 Holland, he offered to build at his own expense what after- 
 wards became the Royal Exchange in London, if a suitable 
 plot of land were placed at his disposal. This was done, 
 and, in the upper part of the building erected, shops were 
 established, the rental for which was handed over to 
 Gresham. He then conceived the idea of converting his 
 own mansion in Bishopsgate into a seat of learning, and 
 endowing it with the revenues arising from the Royal 
 Exchange. Some correspondence about this scheme took 
 place in 1575, and after his death in 1579 it was found that 
 subject to the life interest of his wife he had provided 
 
48 Britain's Heritage of Science 
 
 in his will for the foundation of a college. The first lectures 
 were given in 1597, each professor receiving the stipend 
 of 50, a sum somewhat larger than the revenue of the 
 Regius Professors at Oxford and Cambridge, which was 
 40. The building contained residential quarters for the 
 professors, an observatory, a reading hall, and some alms- 
 houses. It ultimately proved to be too expensive to be 
 maintained with the available funds, and in 1768 was 
 handed over to the Crown; the lectures were then held 
 in the Royal Exchange until 1843, when the present building 
 was erected. 
 
 The appointment of the professors was, by Gresham's 
 will, vested in the Mayor and Corporation of London, who 
 in their first selection consulted the Universities of Oxford 
 and Cambridge, requesting them to nominate two candi- 
 dates for each of the seven professorships ; the final selection 
 included three graduates of Oxford, three of Cambridge, 
 and one who was a graduate of both Universities. The 
 first Professor of Geometry at Gresham College was Henry 
 Briggs (1561-1631), who, after the discovery of logarithms 
 by Napier, calculated complete tables, and thus made 
 their general use possible He also introduced the present 
 notation of decimal fractions, one of the most important 
 advances in the history of arithmetic. The last twelve 
 years of his life were spent at Oxford, where he held the 
 newly-founded Savilian Professorship of Geometry. 
 
 Edward Wright (1560-1615), a mathematician closely 
 associated with Napier and Briggs, translated into English 
 the Latin original of the work which contains the first 
 account of logarithms, but his name deserves chiefly to be 
 remembered in connexion with navigation, to which science 
 he rendered conspicuous service by laying the scientific 
 foundation of the method of constructing maps known as 
 ** Mercator's Projection." Wright studied at Cambridge, 
 was elected to a fellowship of Caius College, and became a 
 teacher of mathematics in the service of the East India 
 Company. 
 
 Among those who, during the seventeenth century, held 
 professorships at Gresham College, we note John Greaves, 
 Isaac Barrow, Robert Hooke, Edward Gunter, Henry Gilli- 
 
H. Briggs, E. Wright, J. Greaves, J. Barrow 49 
 
 brand, and Christopher Wren. Their work now calls for 
 consideration. 
 
 John Greaves (1602-1652), who held also for a time 
 the Savilian Professorship of Astronomy at Oxford, from 
 which position he was dismissed on political grounds in 
 1646, must be considered to be the earfiest scientific metro- 
 logist. He determined with fair accuracy the relation 
 between the Roman and English foot, and also carried out 
 some investigations on Roman weights. One of his suc- 
 cessors at Oxford, Edward Bernard (1638-1697), followed 
 up this work, and published a treatise on ancient weights 
 and measures. 1 
 
 The mathematics of the time, as has already been noted, 
 was under the influence of Descartes, who had invented the 
 method of analytical geometry, in which the position of a 
 point is defined by its distance from two lines at right angles 
 to each other, and which represents a curve in the form of an 
 equation as an algebraic relationship between these distances. 
 When this is done, many problems suggest themselves, 
 such as that of forming the equation to its tangent at any 
 point, or calculating the area bounded by the curve. 
 The solution of such problems led naturally to the concep- 
 tions from which the differential calculus emerged. Isaac 
 Barrow (1630-1677), working along the lines indicated by 
 Fermat and Pascal, succeeded in finding the correct expres- 
 sion for the tangents of a number of curves. A successful 
 lecturer and writer of books, rather than an independent 
 discoverer, he was, nevertheless, an interesting figure in 
 the history of science. The son of a linendraper in London, 
 educated at Charterhouse, he proceeded to study medical 
 subjects as well as literature and astronomy at Cambridge, 
 where he took his degree and obtained a Fellowship at 
 Trinity College. Having been driven out of the University 
 by the persecution of the Independents, he travelled in 
 France and Italy, proceeding thence to Smyrna and Con- 
 stantinople. After spending a year in Turkey, he returned 
 home through Germany and Holland in 1659. In the 
 following year, he was appointed to the Chair of Greek at 
 
 1 See " Report of the Smithsonian Institution, 1890," " The Art 
 of Weighing and Measuring," by William Harkness. 
 
 D 
 
50 Britain's Heritage of Science 
 
 Cambridge, and subsequently was elected Professor of 
 Astronomy at Gresham College. He returned to his Alma 
 Mater in 1663 to take up the newly-founded Lucasian 
 Professorship of Mathematics. Perhaps he performed his 
 most noteworthy scientific act when he resigned his chair 
 in favour of his pupil Newton. 
 
 John Wallis (1616-1703) is another example of a Univer- 
 sity Professor who took an active share in the national life. 
 After passing through Cambridge, where like Barrow he 
 studied medicine, he took Holy Orders in 1641, but became 
 involved in politics; he attained considerable facility in 
 deciphering intercepted despatches of the Royalists, and 
 thereby rendered considerable service to the Puritan party. 
 After holding several livings in succession, he was appointed 
 Savilian Professor of Geometry in 1649, in spite of the 
 opposition of the Independents, who resented his having 
 signed the protest against the execution of Charles I. John 
 Wallis was one of the foremost mathematicians of his time. 
 His work dealt chiefly with applications of Descartes' 
 analytical geometry; but he also published a book on 
 algebra. He seems to have been the first to conceive the idea 
 of representing geometrically the square root of a negative 
 quantity, and is the originator of the sign oo for infinity. 
 Other writings of his dealt with the tides. His efforts to 
 teach deaf mutes to speak, which are said to have been 
 successful, were the first attempts in that direction. Wallis 
 was also interested in investigations on sound, and in a paper 
 published in the Philosophical Transactions he communicated 
 some interesting experiments made by William Noble, 
 fellow of Merton College, and Thomas Pigot, Fellow of 
 Wadham, which contain important investigations on the 
 phenomenon of resonance in sound. Light bodies were 
 placed as riders to investigate the vibrations of stretched 
 wires, and it was shown that when these wires responded 
 to a higher harmonic, the riders were not set in motion if 
 placed at what we now call the nodal points. 
 
 Associated with the group of mathematicians who were 
 contemporaries of Newton, Lord Brouncker (1620-1684) 
 takes an intermediate place between the professional and 
 non-academic class. The title descended to him from his 
 
John Wallis, Christopher Wren 51 
 
 father, who had been elevated to the peerage by Charles I. 
 Brouncker, after obtaining the degree of Doctor of Physic 
 in the University of Oxford, devoted himself to the study 
 of mathematics, and acquired a great reputation at home 
 and abroad by his investigations, which take a high rank 
 in the history of the subject. He made extensive use of 
 approximation by infinite series, and though he is not the 
 originator of continued fractions, he first used them 
 effectively. He was one of the original promoters of the 
 Royal Society, and was named as its President in the Charter. 
 He occupied that position for fifteen years, during which 
 he assiduously devoted himself to its duties. The first years 
 of the Society were necessarily critical ones, and much 
 credit for the judicious and successful direction of its affairs 
 is due to his distinguished services. 
 
 Christopher Wren (1632-1723), though known to fame 
 mainly as a great architect, distinguished himself at Oxford 
 as a mathematician. He had, independently of Newton, 
 suggested the existence of a universal attraction as the 
 cause which retained planets in their orbits, and is highly 
 spoken of in the " Principia." He also was the first to 
 calculate the length of the curve called the cycloid. 
 
 In 1657 he became Professor of Astronomy at Gresham 
 College, and three years later took over the Savilian Profes- 
 sorship at Oxford. Wren's contributions to science were 
 substantial. When the Royal Society expressed a wish 
 that mathematicians should investigate the laws of impact, 
 Huygens, Wallis and Wren sent in independent investiga- 
 tions. All these contained a correct appreciation of the 
 principle of conservation of momentum. The great archi- 
 tect's solution was correct so far as perfectly elastic bodies 
 were concerned. Wallis began with the consideration of 
 inelastic bodies, but ultimately treated the problem in the 
 most general manner, including both perfect and imperfect 
 elasticity. 
 
 A most striking instance of a family, who in many 
 successive generations reached distinction in the academic 
 world, may here be recorded. James Gregory (1638-1675), 
 educated at Aberdeen, published, at the age of twenty- 
 five, a treatise on optics, containing the invention of the 
 
 D 2, 
 
52 Britain's Heritage of Science 
 
 reflecting telescope which goes by his name, but he had no 
 opportunity of actually constructing an instrument. He 
 was also the first to show how the distance of the sun 
 could be deduced by observations of the passage of Venus 
 across the disc of the sun. After a period of study at Padua 
 he became Professor of Mathematics at St. Andrews and 
 subsequently at Edinburgh. His elder brother, David Gregory 
 (1627-1720), was privately engaged in scientific pursuits, 
 and having used a barometer to predict the weather, paid 
 the penalty of his success by being accused of witchcraft. 
 David had three sons, the eldest of whom (1661-1708) 
 successively held the Chair of Mathematics at Edinburgh 
 and the Savilian Professorship of Astronomy at Oxford ; 
 the second son succeeded his elder brother in the Chair of 
 Mathematics at Edinburgh, and the third (Charles) was 
 Professor of Mathematics at St. Andrews. The eldest son 
 of David, the Savilian Professor, was Dean of Christ Church 
 and Professor of Modern History at Oxford. 
 
 Among the descendants of James Gregory we find in 
 three generations four distinguished medical men, all of 
 whom held professorships in the subject, and in the fourth 
 generation, two brothers, the elder of whom, William (1803- 
 1858), became Professor of Chemistry at the Andersonian 
 University in Glasgow, at King's College in Aberdeen, and 
 finally at Edinburgh University. His younger brother, 
 Duncan Farquharson Gregory, entered Trinity College. 
 Cambridge, assisted for a time the Professor of Chemistry, 
 but ultimately devoted his attention to mathematics, and 
 founded the Cambridge Mathematical Journal. 
 
 The scientific activity of the Universities in the second 
 half of the seventeenth century was naturally dominated 
 by the influence of Newton's work. His dynamical investi- 
 gations, leading up to the explanation of the observed motions 
 in the solar system, have already been described, and it 
 is interesting to trace the historical connexion between 
 those discoveries and others which remain to be mentioned. 
 Fortunately his own words describing the succession of 
 ideas as they occurred to him have been preserved : 
 
 " In the beginning of the year 1665 I found the 
 
 method of approximating series and the rule for deducing 
 
David Gregory, Isaac Newton 53 
 
 any dignity of any binomial into such a series. The 
 same year, in May, I found the method of tangents of 
 Gregory and Slusius, and in November had the direct 
 method of fluxions, and the next year, in January, had 
 the theory of colours, and in May folio wing I had entrance 
 into the inverse method of fluxions. And the same year 
 I began to think of gravity extending to the orb of the 
 moon, and having found out how to estimate the force 
 with which a globe revolving within a sphere presses 
 the surface of the sphere, from Kepler's rule of the 
 periodical times of the planets being in a sesquialterate 
 proportion of their distances from the centres of their 
 orbs, I deduced that the forces which keep the planets 
 in their orbs must be reciprocally as the squares of their 
 distances from the centres about which they revolve; 
 and thereby compared the force requisite to keep the 
 moon in her orb with the force of gravity at the surface 
 of the earth, and found them answer pretty nearly. 
 All this was in the two Plague years of 1665 and 1666, 
 for in those days I was in the prime of my age for inven- 
 tion, and minded mathematics and philosophy more than 
 at any time since." 1 
 
 In explanation of this passage it may be noted that the 
 " method of fluxions " was the foundation of the differential 
 calculus, and the " inverse method of fluxions " that of the 
 integral calculus. 
 
 Newton's attention was probably drawn to the study of 
 optics by Barrow. The change of direction of a ray of 
 light on entering a transparent body obliquely had been a 
 favourite subject of investigation in many countries, and 
 the law regulating it was first correctly formulated by Snell 
 (1591-1626), Professor of Mathematics at the University of 
 Leiden. It was reserved to Newton to show that ordinary 
 white light, such as sunlight, consisted of a mixture of 
 different rays. When transmitted through a prism it 
 spreads out into a band of coloured light called the spectrum, 
 because the different rays are deviated to a different degree. 
 With the same transparent material, the measure of the 
 
 1 From a MS. among the Portsmouth Papers, quoted in the 
 preface to the " Catalogue of the Portsmouth Papers." 
 
54 Britain's Heritage of Science 
 
 deviation, or the refrangibility, as we should now call it, 
 is perfectly definite for each ray, and is intimately connected 
 with its colour. Having once separated a ray of definite 
 colour, no further refraction will alter that colour, and it 
 will continue to retain the same properties. As one of 
 the results of this discovery it became apparent that a lens 
 cannot form a perfect image of an object, because different 
 colours are not brought together at the same focus. This 
 appeared to Newton to be such a serious and irremediable 
 defect of telescopes with glass objectives, that he set himself 
 to construct an instrument in which the principal lens is 
 replaced by a mirror. At the request of the Royal Society, 
 who had heard of his telescope, Newton forwarded the 
 instrument to its secretary in December, 1671, with the 
 result that in January of the succeeding year he was elected 
 a Fellow of the Society. The idea of reflecting telescopes 
 had, as already mentioned, previously occurred to Gregory, 
 whose proposal differed, however, essentially from that of 
 Newton in the manner in which the rays were ultimately 
 brought to the observer's eye. 
 
 Newton's name is attached to the coloured rings seen 
 when two slightly curved surfaces of glass are brought 
 together, so that there is a thin circular wedge of air formed 
 near the point of contact. The explanation of these rings 
 presented considerable difficulties, especially with the theory 
 of light adopted by Newton. Though cognisant of the wave- 
 theory of light, which, as shown by Huygens, could explain 
 its propagation and refraction, Newton had good grounds for 
 not accepting it. He saw that the analogy of sound which 
 had been invoked in its favour broke down when applied 
 to the formation of shadows. Sound after passing through 
 an opening spreads in all directions, while light apparently 
 follows a straight course. In other words, sound can turn 
 a corner, while light seems unable to do so. More than a 
 century later, Fresnel gave the correct explanation of the 
 apparent discrepancy, showing that when the experimental 
 conditions were made to correspond, the analogy was main- 
 tained. It is necessary for the purpose that the relation 
 between the size of the aperture and the length of the wave 
 should be the same, and as the waves of light are very short, 
 
Isaac Newton, Robert Hooke 55 
 
 either the aperture through which the light is made to enter 
 has to be very small, or the opening allowing the sound to 
 be transmitted must be large. In the latter case we get 
 " sound shadows," in the former the light spreads out just 
 as the sound does. But such refined considerations only 
 matured in the nineteenth century. In the meantime, the 
 ordinary laws of refraction and reflexion of light could be 
 satisfactorily explained by the corpuscular theory, which 
 seemed better able to cope with the formation of shadows, 
 and Newton therefore preferred the simpler theory. It is 
 unfortunate that an error of judgment, arising really from 
 superior knowledge, paralysed the progress of optics for 
 the time being, but this is the price which had to be paid 
 for the many benefits which accrued to science through the 
 confidence which Newton's work had inspired, and which 
 in all other cases proved to be justified. 
 
 Newton's work on light brought him into controversy 
 with Robert Hooke (1635-1703), a man of great genius but 
 unpleasant temperament, who, for a time, held the Chair 
 of Geometry at Gresham College. Hooke graduated at 
 Oxford and there came into contact with John Wilkins, 
 Thomas Wilkins and Robert Boyle. With an extraordinarily 
 prolific mind he touched on many subjects, insisting on 
 his priority in almost every new idea that was brought 
 forward by others. 
 
 In his " Micrographia " Hooke described important 
 observations on the nature of combustion and of flames. 
 Almost identical experiments were conducted by John 
 Mayow (1640-1679), a fellow of All Souls College, Oxford, 
 and it is impossible now to ascertain to whom they were 
 originally due. Mayow, who was also a distinguished 
 physiologist (see p. 296, Chapter XL), interpreted these ex- 
 periments with remarkable foresight. He truly recognized 
 that there must be a common element in air and in such 
 bodies as nitre, which readily give up their oxygen, and 
 showed that the air contains some constituent which is 
 consumed in combustion; he thus came very near anti- 
 cipating by more than a century Lavoisier's great discovery. 
 
 Hooke was the first who conceived the idea of regulating 
 watches by the balance wheel and spiral spring, and this 
 
56 Britain's Heritage of Science 
 
 alone would give him a high place among discoverers. He 
 first constructed a spirit level, but others had anticipated 
 him in the use of the Vernier. He was the first to use light 
 powders to study the vibration of sounding bodies, and 
 invented an instrument to measure the depth of the sea. His 
 more theoretical speculations always showed acuteness, 
 and might have led to great things if he had been more 
 persevering. In 1674 he published views on a universal 
 gravitation which was to explain the planetary motions ; 
 with the exception of the law of the inverse square, these 
 contained the main principles of the theory which Newton 
 had then already worked out, though not published. In 
 optics, Hooke favoured the undulatory theory, and even 
 expressed the idea that the motion of the particles of the 
 medium which transmitted light was transverse to the direc- 
 tion of propagation, differing in this respect from the waves 
 of sound. Newton, who disliked controversies, is said to 
 have delayed the publication of his book on optics until after 
 Hooke's death for fear of rousing an acrimonious discussion. 
 
 The second edition of Newton's " Principia " was pub- 
 lished in 1713 by Cotes (1682-1716), a distinguished and 
 promising mathematician, who died at the early age of thirty- 
 four, having held during the last ten years of his life the 
 newly-founded Plumian Professorship at Cambridge. 
 
 Among the professional representatives of mathematics 
 during the eighteenth century, it must suffice to name 
 Maclaurin (1698-1746), Professor of Mathematics at Aberdeen ; 
 Matthew Stewart (1717-1785), who succeeded him in the 
 Professorship, and Thomas Simpson, the son of a grocer, 
 who ultimately became Professor of Mathematics at the 
 Royal Woolwich Academy. 
 
 After Newton had placed astronomy on a sound 
 dynamical foundation, a vast field was opened out to further 
 research. It had still to be proved that the law of gravita- 
 tion was sufficient to account for every detail of the motions 
 of celestial bodies, and was not only a first approximation 
 to be supplemented by other effects. Hence it became 
 necessary to increase the accuracy of astronomical observa- 
 tions, and to extend the theoretical investigations, based 
 on the laws of gravity, so as to include the mutual action 
 
Isaac Newton, John Flamsteed 57 
 
 of planets on each other. We have now to consider the work 
 of some of the great men occupied in this task. 
 
 Flamsteed (1646-1720) does not strictly belong to the 
 academic circle, but as he was the first official representative 
 of astronomy in this country it is convenient to speak of his 
 work at this stage. Flamsteed began at an early age to take 
 an interest in astronomical observations. He entered Jesus 
 College, Cambridge, apparently with the object of taking 
 holy orders, but after obtaining his degree, influential friends 
 procured him an appointment as " King's astronomer." 
 About the same time, a Frenchman, called Le Sieur de S. 
 Pierre, visited England with proposals for improved methods 
 o determining longitudes at sea, and Flamsteed in a report 
 expressed the opinion that the project was impracticable, 
 because the position of the stars were not known with 
 sufficient accuracy. According to some manuscripts kept 
 at the Greenwich Observatory, when this came to the ears 
 of King Charles II, "he was startled at the assertion of the 
 fixed stars places being false in the catalogue, and said, 
 with some vehemence, he must have them anew observed, 
 examined and corrected, for the use of his seamen." This 
 incident was the immediate cause of the foundation of Green- 
 wich Observatory, the warrant for its building being issued 
 on June 12th, 1675. When it was completed, Flamsteed 
 set to work to form an improved star catalogue. Up to 
 that time, only observations with the naked eye had been 
 used to determine the positions of the stars, though 
 the cross wire and measuring micrometer had already been 
 invented by Gascoigne. Flamsteed realized the advantages 
 of applying the telescope in combination with a clock. But 
 he had to struggle against great disadvantages; his salary 
 was 100 a year, and he was provided by the Government 
 with neither assistants nor instruments. The latter had 
 to be provided by friends, or made at his own expense. In 
 spite of these difficulties he produced as a result of his labour 
 a star catalogue three times as extensive as, and six times 
 more accurate than, that of Tycho Brahe, which up till then 
 had been in use. Altogether he recorded the positions of 
 3,000 stars. 
 
 Flamsteed was succeeded at Greenwich by Edmund 
 
58 Britain's Heritage of Science 
 
 Halley (1656-1742), who plays an important and interesting 
 part in the history of science. The son of a soap-boiler, 
 and educated at St. Paul's School and Queen's College, 
 Oxford, Halley, at the early age of nineteen, invented an 
 improved method for determining the elements of planetary 
 orbits. Finding that more accurate measurements of the 
 positions of fixed stars were necessary to the progress of 
 astronomy, and that this task was being satisfactorily 
 carried out at Greenwich for the northern heavens, he planned 
 a journey to catalogue some of the southern stars. Through 
 the good offices of the East India Company he obtained a 
 passage to St. Helena, but disappointed with the weather 
 conditions, he returned to England after having registered the 
 positions of about 300 stars. He was an ardent supporter 
 of Newton, and it was in great part due to Halley's efforts 
 that the " Principia " were published. 
 
 Halley was the first to take a comprehensive view of the 
 subject of Terrestrial Magnetism. Some advances had been 
 made in that subject since Gilbert's time, notably by Edward 
 Gunter (15811621), one of the early professors of astronomy 
 at Gresham College, who had taken regular observations of the 
 angle between the direction in which the magnetic needle 
 sets and the geographical north, and found a progressive change 
 in its amount. When the first observation was taken in 
 England, the needle pointed to the east of north; in 1657 
 it pointed due north, and the declination then gradually 
 increased towards the west. Henry Gellibrand (1597-1637) 
 continued and extended these observations. 
 
 In order to explain these slow changes called " the 
 secular variation of terrestrial magnetism," Halley formed 
 the theory that the earth is divided into an outer crust 
 and an inner nucleus, each part possessing its own inde- 
 pendent magnetic poles. A fluid layer was supposed to 
 separate the shell and the core, and Halley imagined the 
 latter to revolve with a slightly smaller velocity than the 
 former about a common axis. It is easy to see that if 
 we accept the premises, a suitable adjustment of the mag- 
 netic axes of the inner and outer parts of the earth would 
 lead to a slow revolution of the resulting magnetic axis. 
 This theory was recently renewed and extended by Henry 
 
Edmund Halley 59 
 
 Wilde, and, though not generally accepted, it shows that 
 Halley recognized that the study of terrestrial magnetism 
 could yield important information on the constitution of 
 the earth and that he looked upon the subject from a 
 wider point of view than that of its mere application to the 
 purposes of navigation. The observations he took in two 
 journeys specially undertaken for the purpose of determining 
 the magnetic declination in different parts of the world, are 
 invaluable to us as historical records. 
 
 Halley's most important discoveries in astronomy were 
 the secular acceleration of the moon's mean motion, the 
 proper motion of the stars, and the periodicity of comets. 
 Comparing the dates at which certain total eclipses of the 
 sun had occurred, Halley could fix the times of the new 
 moon with sufficient accuracy to ascertain that the length 
 of the month was diminishing by about one-thirtieth of a 
 second per century. This implied that the moon's orbital 
 velocity is increasing and may be explained in accordance 
 with Newton's principles, partly as a result of an indirect 
 effect on the earth's orbit round the sun due to the attrac- 
 tion of planets, and partly by friction between the tides and 
 the solid parts of the earth, which increases the length of 
 the day, and indirectly reacts on the moon. 
 
 In all three of the discoveries mentioned, Halley made 
 extensive use of old records; it was by comparing the 
 observed distances of well-known stars from the ecliptic 
 with the observations of the Greek astronomers, that he 
 discovered their independent motions, and, similarly by 
 calculating the orbits of comets observed in previous 
 centuries, he found that some of them pursued nearly 
 identical paths. He concluded that though these were regis- 
 tered each time as new intruders into the solar systems, 
 they might only be reappearances of the same body. As an 
 example, he took the comet which had been observed at 
 intervals of about seventy-six years, and had last been seen 
 in 1682. He predicted that it would be seen again in 1758. 
 Halley did not live to see his prophecy come true : the 
 comet was actually observed on Christmas Day of that 
 year, and is now recognized as a permanent member of the 
 Solar System. 
 
60 Britain's Heritage of Science 
 
 Halley succeeded Waller as Professor of Geometry at 
 Oxford in 1678, and Flamsteed as Astronomer Koyal in 
 1720. When he arrived at Greenwich, he found most of 
 the instruments removed, being the private property of his 
 predecessor. He procured some new ones, and began the series 
 of observations of the moon, the continuance and improve- 
 ment of which has always been the special care of the Royal 
 Observatory. But the age at which he took over his duties 
 prevented his making much progress. 
 
 Halley 's activity covered a large range of subjects, and 
 proved him to be a man of extensive knowledge and great 
 versatility. He investigated, independently of Mariotte, 
 the diminution of the pressure of air as we rise above the 
 surface of the earth, and gave the correct formula for 
 calculating differences in altitude from the barometric 
 records; he observed the aurora borealis, and connected 
 it with terrestrial magnetism by noting that the highest 
 point of the arch lies in the magnetic meridian. He gave 
 the generally accepted explanation of the cause of the 
 trade winds, but was less successful in his attempts to 
 improve the construction of thermometers ; he was the 
 first to give the formula which connects the position of 
 objects and images formed by lenses ; he formed an esti- 
 mate of the quantity of water vapour which enters the 
 atmosphere by the action of solar heat on the oceans; he 
 wrote on the effect of the refraction of air on astronomical 
 observations, worked out the method of deducing the 
 distance of the sun from observations on the transit of 
 Venus, and made valuable contributions to the method of 
 calculating logarithms. He improved the construction of 
 diving bells, and was the originator of " life statistics." 
 There are few men who can show a finer record of scientific 
 activity. 
 
 Halley was succeeded at Greenwich by Bradley (1692- 
 1762), to whom, according to the astronomer Delambre, 
 we owe the accuracy of modern astronomy. Bradley was 
 a nephew of John Pond (1669-1724), a clergyman who had 
 erected an astronomical observatory at his rectory of Wan- 
 stead in Essex, and done some meritorious work on the 
 satellites of Saturn and Jupiter. After graduating at Oxford, 
 
Edmund Halley, James Bradley 61 
 
 Bradley went to reside with his uncle, and became interested 
 in astronomical work. His observational skill soon secured 
 results of sufficient importance to justify his election to the 
 fellowship of the Royal Society in 1718, and the appointment 
 to the Savilian Chair of Astronomy in 1721. He, however, 
 continued to live in Wanstead even after the death of his 
 uncle, visiting Oxford only for the delivery of his lectures. 
 
 It was known to Robert Hooke that the distance of the 
 stars might be ascertained by noting their change of position 
 at different times of the year, for as the earth revolves round 
 the sun, we look upon each star from a slightly different 
 point of view according to the position of the earth in its 
 orbit. The more remote the stars, the smaller will be the 
 displacement, and no one could tell beforehand whether 
 any of them were sufficiently near to show a measurable 
 effect. Hooke himself, with his accustomed impetuosity, had 
 tried the method, and using a star which for particular 
 reasons was specially fitted for the purpose, believed that he 
 had observed a comparatively large displacement. Samuel 
 Molyneux (see page 90) had erected a suitable telescope 
 at his house in Kew Green, for the purpose of verifying 
 Hooke's observations, and observed the same star on a 
 series of evenings during the early part of December, 1725, 
 but no material change of position was noted. At this 
 stage Bradley, a friend of Molyneux, began to take part 
 in the investigation. On visiting the Observatory at Kew 
 on December 17th, curiosity tempted him to take an observa- 
 tion, and he noted that the star had slightly increased in 
 declination. To his surprise, however, the displacement was 
 found to be in a direction opposite to that to be expected 
 if it were due to the proximity of the star. The apparent 
 movement was then continuously watched, and the star 
 was found to describe a closed curve, returning at the end of 
 a year's observation very nearly to its original position. 
 Bradley, much puzzled by the result, at first thought that 
 the displacement might be due to a periodic change in the 
 inclination of the earth's axis. In order to test this idea, 
 it was necessary to observe stars in different parts of the 
 sky, and Bradley set up a new instrument at his home in 
 Wanstead for the purpose. He found, indeed, that evesy 
 
62 Britain's Heritage of Science 
 
 star examined described an elliptic curve similar to that 
 observed with Molyneux's telescope, but the difference? 
 in size and shape did not agree with the hypothesis he had 
 formed. At last the true explanation occurred to him. 
 
 Owing to the fact that light is not transmitted instanta- 
 neously, a star is not actually seen in the direction in which 
 it would appear if light took no time in its passage to the 
 earth The cause of this curious effect may be illustrated by 
 a familiar analogy. A person driving in a carriage during a 
 shower of rain on a windless day, though the drops fall 
 down vertically will feel them striking against his face, as if 
 he were meeting the wind. Hence, holding up an umbrella 
 to shield himself, he would have to tilt it forwards and if 
 he were unaware of his own motion, he would believe that the 
 drops fall at an angle slightly inclined to the vertical. Sub- 
 stituting Newton's corpuscles of light for the drops of rain, 
 it becomes clear that the velocity of the earth affects the 
 angle at which the light coming from a star seems to reach 
 us. This effect is called the " aberration of light." As the 
 earth's velocity changes in direction while it revolves round 
 the sun, a star, though stationary, will appear to describe 
 a closed curve. From the known velocity of the earth, and 
 the extent of a star's apparent motion, the velocity of light 
 may be calculated, and Bradley found it to agree closely 
 with that which had been calculated by Roemer from the 
 eclipses of Jupiter's satellites. The accuracy of Bradley 's 
 observations may be appreciated by noting that if the star's 
 position in the sky be such that it appears, owing to the 
 aberration of light, to describe a circle, the angular diameter 
 of the circle is about that of a halfpenny piece placed at a 
 distance of 420 feet; the dimensions of the curve described 
 by the star were measured by Bradley with an accuracy of 
 about two per cent. 
 
 After Bradley had established himself at Greenwich 
 Observatory, he continued his observations, and found that 
 the stars after a year's interval did not return to the same 
 position, as they ought to do if the aberration of light were 
 the only cause of their apparent displacement. Returning 
 to his original idea of a small change in the inclination of 
 the earth's axis, he then found it to account satisfactorily 
 
James Bradley, Nevile Maskelyne 63 
 
 for this residual effect. He thus discovered the " nutation " 
 of the earth's axis, which is caused by an attractive effect 
 of the sun on the equatorial protuberance of the earth, 
 which is not an exact sphere, but a spheroid with a larger 
 equatorial than polar diameter. 
 
 When it is considered that every measurement of a star's 
 position has to be corrected so as to eliminate the effects of 
 aberration and nutation before its true position is ascer- 
 tained, Delambre's judgment that the accuracy of astro- 
 nomical observations owes everything to Bradley cannot 
 be gainsaid, and we shall also probably agree with the same 
 author 1 that " ce double service assure a son auteur la place 
 la plus distinguee apres celle de Hipparque et de Kepler, et 
 au-dessus des plus grands astronomes de tousles ages et de 
 tous les pays." 
 
 After Bradley's death, Nathaniel Bliss, Savilian Professor 
 of Geometry at Oxford, was appointed Astronomer Royal, 
 but he only held the position for two years. Nevile 
 Maskelyne (1732-1811), a man of much greater ability, 
 next had charge of Greenwich Observatory. He graduated 
 as seventh wrangler at Cambridge in 1754, and twelve years 
 later was appointed to the post of Astronomer Royal, the 
 duties of which he discharged successfully during forty- 
 six years. His mind was first turned to astronomy as 
 a boy of sixteen by watching a solar eclipse. During a 
 voyage undertaken to observe the Transit of Venus, in 
 1761, he became interested in a process for determining 
 longitudes by measuring the distances of selected stars 
 from the moon, and he ultimately succeeded in introducing 
 this method as a regular practice in navigation. The im- 
 portance of the procedure consisted in its being independent 
 of timekeepers, and it consequently retained its place until 
 recently, when the construction of chronometers improved 
 so much that it lost its practical value. 
 
 In order to make the tabulations of the position of the 
 moon and of the selected stars readily accessible to navi- 
 gators, Maskelyne persuaded the Government to issue an 
 annual publication. This was the origin of the Nautical 
 
 1 Delambre, " Histoire de I'Astronomie au dix huiti&ne si&ele." 
 
64 Britain's Heritage of Science 
 
 Almanac, which has proved to be of immeasurable value 
 to all seamen. Maskelyne remained its editor until his 
 death. He also re -organized in many ways the work and 
 instrumental equipment of the Greenwich Observatory, and 
 instituted an important research which led to the first 
 determination of the density of the earth. To appreciate 
 the importance of this experiment, we must remember 
 that by noting the rate of fall of a body we can measure the 
 force with which the earth attracts it, but not knowing the 
 total mass of the earth, we cannot tell how much one pound 
 of matter would attract another pound at a given distance. 
 That can only be ascertained by measuring the attraction 
 between masses both of which are known. From the result 
 of such a measurement the mass of the earth may be calcu- 
 lated, and as its dimensions are known, we can deduce its 
 mean density. The problem of finding the density of the 
 earth is, therefore, identical with that of finding the gravita- 
 tional attraction between known masses, and herein lies 
 its chief value. Maskelyne 's method consisted in deter- 
 mining the deflexion of a plumb line in the neighbourhood 
 of a mountain. As this deflexion cannot be observed directly, 
 we must have recourse to an indirect method; but this 
 presents no difficulties. If the latitudes of two places, one 
 to the north and the other to the south of a mountain, 
 be determined astronomically, and their distances directly 
 measured, the discrepancy between the observed and 
 measured differences of latitude gives us the data we want 
 for calculating the gravitational effect of the mountain. 
 The method cannot give very accurate results, as the density 
 of the material composing the mountain must be taken into 
 account, and this requires a geological survey and complicated 
 calculations. Maskelyne was assisted in his measurements, 
 which were conducted in the neighbourhood of the mountain 
 Schehallien in Perthshire, by Charles Hutton (1737-1823), 
 Professor of Mathematics at the Military Academy, Wool- 
 wich; the figures they obtained showed that bulk for bulk 
 the material of the earth is on the average between 4*48 and 
 5 -38 times heavier than water. 
 
 While learning at Oxford and Cambridge rapidly declined 
 after the first impulse of Newton's discoveries had died away, 
 
William Cullen, Joseph Black 65 
 
 the reputation of academic science in the eighteenth century 
 is retrieved by the splendid record of the Scotch Univer- 
 sities, and notably of Edinburgh. It was indeed a brilliant 
 period in which Black originated quantitative chemistry, 
 Hutton founded the science of geology, Robert Simpson 
 taught mathematics, and John Robison, natural philosophy, 
 while Watt worked out his inventions, and in other branches 
 of knowledge Adam Smith and David Hume added to the 
 fame of their Universities. 
 
 William Cullen (1710-1790), who may be said to be the 
 founder of the Scotch school of chemists, studied at the 
 University of Glasgow, and at the age of nineteen obtained, 
 through the influence of friends, a post as surgeon on a 
 merchant ship sailing to the West Indies. On his return 
 home he became a medical practitioner in his native town, 
 Hamilton, but a small legacy enabled him to spend two 
 years at Edinburgh, in order to pass through a regular 
 course of study. After a period of activity in Glasgow, 
 during which he occupied the Chair of Medicine, and assisted 
 in founding the medical school in that university, he returned 
 to Edinburgh as Professor of Chemistry. Cullen was the 
 discoverer of the lowering of temperature which takes place 
 when a liquid evaporates, or a solid dissolves in a liquid. 
 He also experimented on the heat generated in chemical 
 transformations . 
 
 It was no doubt these researches on heat which directed 
 Joseph Black's attention to that subject. Black (1728- 
 1799) was the son of a Scotch wine merchant living at 
 Bordeaux. He was educated at Belfast, Glasgow and Edin- 
 burgh, studied medicine at the latter University, and 
 presented to it at the age of twenty-six an inaugural disser- 
 tation containing discoveries of fundamental importance to 
 chemistry. Limestone, which forms so important a portion 
 of the earth's surface layers, was at that time considered 
 to be an elementary substance. It was known, of course, 
 that at a high temperature its properties are changed; it 
 becomes quicklime, which gives off a great amount of heat 
 when brought into contact with water. This was explained 
 at the time by supposing that the limestone absorbed, when 
 heated, an imaginary thermal or caustic substance which 
 
 E 
 
66 Britain's Heritage of Science 
 
 it gave out again when brought into contact with water. 
 The corresponding compound of magnesia behaved similarly, 
 and was not clearly distinguished from the calcium salt. 
 Magnesia had then already some importance as a drug, 
 and the title of Black's dissertation " De humoro acido a 
 cibis orto et magnesia alba " indicates that it was the medi- 
 cal aspect that led him to the research. Black proved that 
 the current explanation was wrong, and that, instead of 
 absorbing anything, limestone, on heating, lost in weight, 
 and gave out a gas, which he collected and identified with 
 Helmont's " gas sylvestre." He definitely proved that this 
 gas, now known as carbonic acid, differed from air, because 
 it could combine with caustic soda and potash, which air 
 could not; he also showed that atmospheric air always 
 contained small quantities of it. Black further established 
 the essential differences between the behaviour of calcium 
 and magnesium compounds. His use of the balance in 
 these researches justifies the claim that has been made on 
 his behalf of being the father of quantitative chemistry. 
 
 In his researches on heat, Black showed an equal power 
 of selecting the fundamentally important questions, and of 
 treating them with experimental skill and scientific precision. 
 His results were explained in his lectures, but many of them 
 remained unpublished until after his death It is, therefore, 
 not always easy to fix the dates at which his discoveries 
 were communicated to his students, so as to compare them 
 with similar results arrived at in other countries, notably 
 by Wilcke at Stockholm, and Deluc, who, born in 1727 at 
 Geneva, left his native town at the age of forty-three and 
 after various travels settled down in England, and died at 
 Windsor in 1817. There is no doubt, however, that Black 
 was the discoverer of latent heat. Deluc had noted the slow 
 melting of ice, and made the observation that when a mixture 
 of ice and water is heated, the temperature of the water 
 remains constant until all the ice is melted, but Black went 
 a good deal further, and not only measured the heat required 
 to melt the ice, but showed it to be the same in amount as 
 that which was set free in freezing the water. He applied 
 the term "latent heat," which is still in use, and his 
 measurements were correct to two per cent. The corre- 
 
Joseph Black 67 
 
 spending phenomenon was observed when water was 
 converted into steam, but, owing to the greater experimental 
 difficulties, the numerical value obtained was not so accurate. 
 Black also had clear ideas on the differences in the amounts 
 of heat required to raise different substances through the 
 same range of temperature; but handed over this part of 
 the subject to his pupil Irvine. 
 
 An interesting paper by Black- on " The supposed effect 
 of boiling on water in disposing it to freeze more readily, 
 ascertained by experiments " (Phil. Trans. 1775) is worth 
 reading as an example of clear thinking, lucid description, 
 and good experimenting. It is still to-day the common 
 belief of plumbers, and those who derive their knowledge 
 of science from plumbers, that hot-water pipes freeze more 
 readily in winter than cold ones. This belief seems to have 
 had its origin in the report, made on good authority, that 
 when water is exposed at night in the dry atmosphere of 
 the Indian winter, in order to convert it into ice through 
 the loss of heat by radiation, it is essential to boil it 
 previously. In order to find the reason for this, Black exposed 
 two similar cups, one filled with boiled and the other with 
 unboiled water, to a temperature below the freezing point, 
 and saw, indeed, ice crystals appearing on the surface of 
 the former, while the latter remained clear. But on intro- 
 ducing thermometers, he discovered that the temperature 
 of the unboiled water had fallen below the freezing point, 
 without being converted into ice, which, however, formed 
 as soon as the water was stirred. Black was aware of 
 Fahrenheit's observation that water, when kept perfectly 
 quiescent, could be cooled considerably below the normal 
 temperature of freezing. The question that remained to 
 be solved was, therefore, this : why should the unboiled 
 water be more easily undercooled than that which had been 
 boiled? The only effect that boiling can have on the water 
 is to expel the absorbed air, and one might be tempted to 
 reason from the above experiment that the absorbed air 
 favours the undercooling. But this explanation is negatived 
 by the circumstance that Fahrenheit's experiments were 
 conducted in a vessel from which the air had been removed 
 by the air pump. Black, realizing, therefore, that water 
 
 E 2 
 
68 Britain's Heritage of Science 
 
 deprived of its air could be undercooled as well as ordinary 
 water, concluded that the cause of the difference lay in the 
 act of re-absorbing the air. He suggested that the absorp- 
 tion caused (possibly through minute differences of tempera- 
 ture or density) sufficient circulation, or, as he expressed it, 
 " agitation " to prevent the undercooling. It is remarkable 
 that the subject has never been examined further, but 
 Black's explanation finds some support in the experiments 
 made by Thomas Graham, who showed that the admission 
 of air into a previously boiled and undercooled solution of 
 Glauber salt, set the crystallization going, and this was 
 traced to a slight diminution of the solubility of the salt 
 in water which contains air. 
 
 To Black must also be given a place in the history of 
 aeronautics, as he was the first to make the attempt to fill 
 a balloon with hydrogen; this was as early as 1767, two 
 years before Montgolfier made his first balloon ascent. 
 
 Black practised as a medical man ; he held for a time the 
 Chair of Anatomy and Chemistry at Glasgow, but distrustful 
 of his qualifications as a chemist, exchanged it for that of 
 Medicine. In 1766 he succeeded Cullen in the Professorship 
 of Medicine and Chemistry at Edinburgh. In private life 
 he was fond of painting; the weakness of his health is 
 probably responsible for a certain lack of energy which 
 sometimes led him to abandon his work when half finished, 
 and to leave many of his researches unpublished. " No man 
 had less nonsense in his head," said Adam Smith, " than 
 Black." 
 
 One further contribution of the Scotch Universities to 
 chemistry remains to be noticed. Rutherford (1749-1819), 
 a medical man who occupied the Chair of Botany at Edin- 
 burgh, was the first to isolate the gas nitrogen in 1772, by 
 burning substances in an enclosed volume of air, and 
 absorbing the carbonic acid formed in the combustion. 
 
 Black's lectures were edited after his death by John 
 Hobison (1739-1805), a man of great intellectual powers, 
 who, like so many other men of science of the time, led an 
 eventful life. After a brief period of study at Glasgow, he 
 became tutor to the son of Admiral Knowles, who as a 
 midshipman was about to accompany General Wolfe to 
 
Joseph Black, John Robison 69 
 
 Quebec. Robison took part in the war, and after his return 
 home was charged by the Board of Longitude to under- 
 take a journey to the West Indies for the purpose of 
 testing a chronometer constructed by John Harrison. A 
 few years later Robison accompanied, as private secretary, 
 Admiral Knowles to Petrograd, on his appointment as 
 President of the Russian Board of Admiralty. For a time 
 he also held the mathematical professorship attached to the 
 cadet corps of nobles at Petrograd. Before he went to Russia 
 Robison had occupied during four years the Chair of 
 Chemistry at Glasgow, and after his return home in 1773 he 
 became Professor of Natural Philosophy at Edinburgh. 
 When the Royal Society of Edinburgh received its charter 
 in 1783 he was elected secretary, and held this position until 
 within a few years of his death, which took place in 1805. 
 
 Robison enjoyed a high reputation among his contem- 
 poraries, but we cannot assign any great advance in science 
 to him. He was a man of great learning and published 
 researches, which only just fell short of marking a distinct 
 step. He deserves to be remembered even if it were only 
 for his connexion with James Watt, who owed him much 
 assistance and encouragement. Robison was always inter- 
 ested in steam, and had, before Watt's improvement of the 
 steam engine, conceived the idea of applying the power 
 of steam to the propulsion of vehicles. 
 
 David Brewster collated some of the manuscripts left by 
 Robison, and published them in a work of four volumes : 
 " Elements of Mechanical Philosophy." 
 
 It appears from this work that Robison undertook 
 several researches, which he omitted to publish. Among 
 them was an experimental investigation on the law of action 
 of electrical forces. This, he states, was communicated to 
 a " public society " in 1769, some years before Cavendish 
 and Coulomb discovered the law of the inverse square. The 
 experiments which are described in the published work, 
 lead unmistakably to that law, but it is not stated whether 
 they were the original ones or were repeated and improved 
 upon later. Robison makes no claim in this respect, but 
 refers to Cavendish as having " with singular sagacity and 
 address, employed his mathematical knowledge in a way 
 
70 Britain's Heritage of Science 
 
 that opened the road to a much further and more scientific 
 prosecution of the discovery, if it can be called by that 
 name," and finally adopts Coulomb's measurements as con- 
 clusive. It seems, however, to have escaped notice hitherto 
 that Robison in his experiments used what must be con- 
 sidered to be the first absolute electrometer, the electric 
 force being balanced by the action of gravity, and there- 
 fore reducible to its value in terms of dynamical units. 
 
 Robison was a strong adherent of Boscovich, the Italian 
 philosopher, who tried to dispose of the difficulties inherent 
 in the definition of matter by considering atoms to be merely 
 centres of forces without extension. Boscovich had applied 
 his theory to the effects of ponderable matter on the trans- 
 mission of light, and Robison took up this subject and treated 
 it in a paper (Ed. Phil. Trans., Vol. II., 1790), which in 
 many ways is remarkable. Its title, " On the motion of light 
 as affected by refracting and reflecting substances which are in 
 motion," shows that it deals with one of the most puzzling and 
 difficult problems of physics . It was the phenomenon of aberra- 
 tion of fight discovered by Bradley which gave practical im- 
 portance to the subject, and, without entering into details, it 
 deserves to be recorded that Robison had the idea of apply- 
 ing telescopes filled with water to clear up experimentally 
 some of the obscure points, which up to our own times have 
 puzzled mathematicians. This idea was revived and success- 
 fully applied later by Airy, but Robison failed on account 
 of the difficulty of obtaining water that was sufficiently 
 transparent. Although his ideas are now superseded, the 
 paper gives us some idea of the powers of the man of whom 
 Watt wrote : "He was a man of the clearest head and the 
 most science of anybody I have ever known." 
 
 Robison's successor, both in the Chair of Physics and 
 as Secretary of the Royal Society of Edinburgh, was John 
 Playfair (1748-1819), previously Professor of Mathematics, 
 who had taken part in the geological survey connected 
 with the Schehallien experiment of Maskelyne and Robert 
 Hutton. His first work was a book on " Button's Theory 
 of the Earth," which had considerable influence in making 
 James Button's geological theories known and appreciated. 
 His mathematical contribution to science is mainly con- 
 
Robison, Desaguliers, Robert Smith 71 
 
 fined to a publication " On the Arithmetic of Impossible 
 Quantities." 
 
 Though but little work of importance was produced at 
 Oxford and Cambridge in the eighteenth century, science 
 was kept alive. John Theophilus Desaguliers (1683-1744), 
 the son of a French Protestant clergyman, who left his 
 country on the revocation of the Edict of Nantes, was 
 brought to England while an infant. He studied at Oxford 
 and acted as Professor of Physics in that University. He 
 settled in London in 1712, and ultimately became Chaplain 
 to the Prince of Wales. After leaving Oxford, he became 
 a voluminous writer on many subjects. In his first paper 
 he describes a new method of building chimneys so as to 
 prevent their smoking. He invented a machine for measur- 
 ing the depth of the sea and other mechanical contrivances. 
 He is best remembered by his electrical work in which he 
 clearly defined the nature of a conductor as distinguished 
 from bodies which could be electrified by friction with- 
 out being attached to insulating handles. He enjoyed a 
 great reputation, being consulted by men of science, and 
 notably by James Watt in connexion with steam engines, 
 having himself introduced some improvements in their 
 construction. 
 
 At Cambridge, Robert Smith (1689-1768), as Plumian 
 Professor, made some valuable contributions to acoustics, 
 published in a separate volume " Harmonics." His great 
 treatise on light contains a wealth of information, and still 
 possesses considerable historical interest. It had a great 
 influence at the time, stimulating the study of optics, more 
 especially with regard to its practical applications in the 
 construction of optical instruments. 
 
72 Britain's Heritage of Science 
 
 CHAPTER III 
 
 (Physical Science) 
 
 THE NON-ACADEMIC HERITAGE 
 during the Seventeenth and Eighteenth Centuries 
 
 THE scientific investigator should be endowed with 
 knowledge, critical judgment, and inventive power. 
 For the first two attributes we must look mainly to pro- 
 fessional men, who have gone through a recognized training 
 and are engaged in teaching or research. Such men, brought 
 up under the compelling influence of accepted currents of 
 thought, though well prepared to advance their subject 
 and even to make new discoveries along the paths opened 
 out by their predecessors, are heavily handicapped when 
 the time has come for a revolution of fundamental ideas. 
 Often they have risen to the occasion, and thrown anti- 
 quated doctrines overboard, but sometimes the academic 
 tradition is strong enough to prevail. The advantage, then, 
 lies with those who are not burdened by the weight of 
 inherited opinions, and great opportunities are offered to 
 the inexperienced youth or the enthusiastic amateur. What 
 constitutes an amateur ? All efforts to define the term 
 must fail, because we cannot define what is not definite. 
 The word in its literal sense denotes a man who pursues 
 a subject for the love of it, but it carries a suggestion of weak- 
 ness, or rather a suspicion, associated more particularly 
 with amateurs in art, that they have not completely mastered 
 their craft. So far as the actual work of research is con- 
 cerned the difference between the amateur and professional 
 man is not always pronounced, and is frequently obliterated ; 
 some University professors have retained through life the 
 characteristic attributes of free lances of science, and 
 

 The Hon. Robert Bovle 
 
 From a -baintinp bv F. K 
 
Robert Boyle 73 
 
 amateurs have occasionally rivalled professional scholars in 
 profundity of knowledge and academic conservatism. 
 
 The essential distinction and it is an important one 
 lies in the wider range of subjects which the professional 
 man of science has to cover. He may have to lecture or 
 advise students on matters which are outside his own 
 researches, or he may have to direct an institution burdened 
 with a quantity of routine work which cannot be neglected. 
 He both gains and loses by the exigencies of his duties ; while 
 his compulsory reading may supply him with analogies which 
 are frequently fertile in valuable suggestions, he is often drawn 
 away to side issues, and is tempted to adopt a dogmatic 
 attitude on those portions of his subject which he teaches 
 or directs, but is not much interested in. 
 
 The non-academic class of workers are free from any 
 routine which they do not impose on themselves and, as 
 might be expected, present less uniformity in their aims and 
 modes of working. What greater contrast could, indeed, 
 be found than that between the three men whose work 
 forms the main subject of this chapter : Robert Boyle, 
 the indefatigable experimenter and voluminous writer, who, 
 though refusing a peerage and the Presidency of the Royal 
 Society, found his chief pleasure in intercourse with other 
 men of science : Henry Cavendish, the taciturn recluse, who 
 disliked contact with the ordinary affairs of life, and was 
 remiss even in publishing his revolutionizing researches; 
 William Herschel, the poor Hanoverian oboist, who had to 
 earn his living as a teacher of music, and fight his way 
 up until, with telescopes constructed by his own hands, he 
 attained unrivalled pre-eminence as an astronomer. 
 
 Robert Boyle (1627-1691) belonged to an old Hereford- 
 shire family, whose name is mentioned in Domesday Book 
 as Biuville. His father, Richard, described by Thomas Birch 
 as one of the greatest men of his age, passed through a 
 course of study at Cambridge, and having spent some time 
 in London as a student of the Middle Temple, went to 
 Ireland to make his fortune, married a rich wife, and ulti- 
 mately became Baron of Youghall, Viscount of Dungarvan 
 and Earl of Cork. He was married twice and had fifteen 
 children. Robert, the last but one of them, received his 
 
74 Britain's Heritage of Science 
 
 education partly at Eton, and then privately at his father's 
 newly-purchased property near Stalbridge in Dorsetshire. 
 At the age of eleven he was sent on a lengthy journey to 
 the continent, accompanied by an elder brother and a 
 French tutor, Marcombes; they reached Geneva, where 
 they stayed nearly two years before proceeding to Italy. 
 At Florence, Boyle became acquainted with the works of 
 Galileo, and one can imagine the impression the death of 
 that great man, which occurred during his stay, must have 
 made on his youthful mind. The party proceeded to Rome, 
 and ultimately set out on their return journey, but found 
 themselves at Marseilles without means, as a remittance 
 from Boyle's father had been stolen by the messenger. 
 Almost penniless, they made their way back to Geneva, 
 M. Marcombes' native place, and ultimately the two 
 brothers reached England in the summer of 1644. They 
 found their father dead, and the country in such confusion 
 that it was nearly four months before Robert Boyle, who 
 inherited the manor at Stalbridge, could make his way 
 thither. 1 In London, Robert Boyle made the acquaintance 
 of John Wallis, Christopher Wren, and other distinguished 
 men, whose weekly meetings were destined to lead to the 
 foundation of the Royal Society. Though his scientific 
 studies were interrupted by an enforced visit to his dis- 
 ordered Irish estates, which extended over two years, he 
 settled down in 1654 at Oxford, where, during the following 
 fourteen years, he devoted himself entirely to scientific 
 research. He spent the remainder of his life in London, 
 taking an active part in the affairs of the Royal Society 
 until two years before his death. Boyle had strong religious 
 views; but he refused to take orders on the ground that 
 he felt no inner call, and thereby lost the appointment as 
 Provost of Eton. He so strictly interpreted the command 
 of the New Testament not to swear " neither by heaven, 
 nor by earth, nor by any other oath," that he refused the 
 Presidency of the Royal Society, because the Charter pre- 
 scribed the taking of an oath on his accession to office. By 
 his will he founded the " Boyle Lectures " for the defence 
 
 1 " Dictionary of National Biography." 
 
Robert Boyle 75 
 
 of Christianity. He was never strong in health; weak 
 eyesight troubled him throughout life, and a painful disease 
 caused him much suffering in later years. 
 
 His scientific work is distinguished by great experi- 
 mental skill, and a determination to remain free from the 
 bias of preconceived notions. In his travels he had 
 become proficient in several languages, and he continued 
 to keep himself informed of what was being done on the 
 continent of Europe. Having read an account of Guericke's 
 air-pump (or, as Boyle calls it, " wind-pump "), he set 
 to work to construct one, and with the help of Robert 
 Hooke, who appears to have acted as his assistant at that 
 period, succeeded in effecting considerable improvements. 
 With this pump a large number of experiments were per- 
 formed, all devised to prove some definite point, such as 
 comparing the weight of air with that of water, or inves- 
 tigating what he calls the spring of air. He showed that 
 flames are extinguished and hot coal ceases to glow in a 
 partial vacuum. He proved that magnetic and electric 
 actions persist in his exhausted receiver, and that warm 
 water begins to boil under reduced pressure. The action 
 of the pump in removing air from a vessel suggested the 
 inverse process of increasing the pressure, and this led to 
 the construction of the compression pump. In his measure- 
 ments he attained considerable accuracy; the specific 
 gravity of mercury was correctly determined to one half 
 per cent., that of air to about 20 per cent. 
 
 Boyle's name is associated with the important law 
 connecting the density of air with its pressure. The proof 
 of the law is contained in a long paper entitled " Defence 
 of the doctrine touching the spring and weight of air," 
 published in 1662. The range of pressures covered by the 
 experiments extended from four atmospheres (involving 
 the use of glass tubes ten feet long) down to 1J inches of 
 mercury; the agreement between observed pressures and. 
 those calculated from the changes of volume, assuming that 
 density and pressure are proportional, was quite sufficient 
 to prove the correctness of the law. The often repeated 
 assertion that it was Townley who first drew Boyle's 
 attention to the significance of these observations and for- 
 
76 Britain's Heritage of Science 
 
 mulated the law is not justified, and is founded apparently 
 on some misconception of a passage in Boyle's account of 
 his experiments. 
 
 We owe to Boyle the use of the term " barometer," 
 and he constructed an instrument in which the mercury 
 is replaced by a short column of water with sufficient air 
 above to counter-balance the atmospheric pressure. When 
 no temperature changes interfere, such an instrument 
 would be considerably more sensitive than an ordinary 
 barometer. With it Boyle could observe the difference of 
 pressure between the roof and floor of Westminster Abbey, 
 thus confirming Pascal's experiment without having to 
 ascend a mountain. 
 
 In his optical experiments Boyle showed that colours 
 are produced by a modification of the light which takes place 
 at the surface of the coloured body. The connexion between 
 radiant heat and light was illustrated by covering half of a tile 
 with black and the other half with white paint, when he 
 found that in sunlight the black paint becomes hot while 
 the white remains cold. He also first drew attention to the 
 colours of thin films such as soap bubbles. He investigated 
 freezing mixtures and discovered that when salt is added to 
 snow or ice the observed cooling is connected with the lique- 
 faction of the salt. Boyle invented the hydrometer and 
 showed how to determine by means of it specific gravities not 
 only of liquids but also of solids. He made extensive chemi- 
 cal experiments, and correctly explained a chemical reaction 
 as being due to the substitution of an atom of one kind for 
 an atom of another kind in the original compound. 
 
 Boyle's completed works occupy six folio volumes; 
 he is somewhat prolix in his discussions, but his descrip- 
 tions are always clear and interesting. By the manner 
 in which he allows himself to be led from one experiment 
 to another he almost reminds one of Faraday, though his 
 indiscriminate mixing of what is important with what is 
 of minor value partakes a little of the weakness of the 
 dilettante. He was highly esteemed by his contemporaries, 
 and Newton, as well as many other eminent men of science, 
 showed, in their correspondence, that they attached great 
 value to his opinions. 
 
Robert Boyle, Brooke Taylor 77 
 
 It is comparatively rare to find an eminent mathema- 
 tician among amateurs, but a noteworthy example is 
 furnished by Brooke Taylor (1685-1731), a wealthy man 
 who, having completed his studies, soon acquired a reputa- 
 tion by his researches, and was elected into the Royal 
 Society in 1712; two years later, he became one of the 
 secretaries of that body. Taylor's theorem is known to 
 every student of mathematics; in the subject of mathe- 
 matical physics we owe to him the formula which connects 
 the period of vibration of a stretched string with its length, 
 cross-section and tension. 
 
 The meetings of the Royal Society in the early days 
 of its activity were only partly occupied by the reading 
 of papers. Experiments were shown and discussed, and 
 new subjects were proposed for investigation; particular 
 questions were occasionally assigned to individual Fellows 
 for enquiry and report. In this manner scientific research 
 was organized more successfully than has ever since been 
 possible. To assist the Society's work, a curator was 
 appointed, whose special duties consisted in preparing the 
 experiments for the meetings. A wide range of subjects 
 was therefore brought to the notice of the meetings in an 
 attractive form, and we find that many Fellows extended 
 their researches in consequence of the stimulus received 
 at the meetings. The inducement to do so was more 
 especially strong with those who acted as curators, and this 
 may be one of the reasons why Robert Hooke, the first 
 who occupied that position, touched upon such a variety 
 of subjects in widely different fields of enquiry. Among 
 those who were employed at the beginning of the eighteenth 
 century to prepare experiments, though he does not seem 
 to have received the title of curator, was Francis Hauksbee, 
 to whom we owe many interesting observations. Passing 
 a strong current of air over the reservoir of a barometer, 
 he found that the height of the column of mercury dimi- 
 nished by two inches, thus proving the reduction of pressure 
 accompanying the increase of kinetic energy in fluid 
 motion. He connected this observation with the fall of 
 the barometer during a gale of wind. He was the first 
 who investigated the transmission of sound through water, 
 
78 Britain's Heritage of Science 
 
 and made some interesting experiments on the intensity of 
 sound transmitted through air of different densities. 
 
 Hauksbee deserves, perhaps, most to be remembered 
 by his researches in electricity. Frequent references occur 
 in the publications of the time to the curious luminosity 
 in the partial vacuum above the barometer column which 
 occasionally appears when the mercury is made to oscillate 
 in the dark. Hauksbee had the idea that the luminosity 
 was connected with some electrical action. To test this, 
 he mounted a spherical glass vessel so that it could be made 
 to rotate round a central axis. The vessel was exhausted, 
 and, being set in motion, became highly electrified by 
 friction when the hand was placed against it. At the same 
 time the remnant of air in the vessel became luminous, 
 and Hauksbee rightly concluded that the luminosity was of 
 the same nature as that observed in the barometer; in 
 the latter case, of course, the friction is produced internally 
 between the moving mercury and the glass. Incidentally 
 it may be mentioned that the first record of an electric 
 spark occurs in Hauksbee 's writing; it was produced by 
 approaching the finger towards the electrified glass vessel, 
 and is said to have been an inch long. 
 
 Very little is known about the life of Hauksbee, or of 
 that of Stephen Gray and Granville Wheler, two other 
 important contributors to our knowledge of electricity. 
 Gray, elected a Fellow of the Royal Society in 1732, was 
 the first to point out the effects of conductivity in electrical 
 experiments, classifying bodies as conductors or insulators. 
 He had been led to this fundamental distinction by 
 experimenting with a glass tube which was closed at one 
 end by a cork, and noting that, when the glass was excited 
 by friction, the cork attracted light bodies, thus showing 
 that it had become electrified. When a rod several feet 
 in length carrying an ivory sphere at its further end was 
 inserted in the cork, the sphere also became electrified. 
 When other experiments did not give the expected result, 
 Gray seems to have consulted another Fellow of the Royal 
 Society, Granville Wheler, a clergyman, who suggested to 
 him that the cause of the failure was likely to be due to the 
 difficulty of supporting the bodies experimented upon in 
 
Francis Hauksbee, Robert Symmer 79 
 
 such a manner that the electricity could not escape to 
 earth. He advised the use of silk threads, as owing to 
 their thinness they were likely not to conduct so well. 
 This proved to be successful, not for the reason given 
 but because silk is an excellent non-conductor. Besides 
 silk, other substances like glass and resins were recognized as 
 insulators, and the range of experimentation was thereby 
 much enlarged. 
 
 There was at the time considerable confusion owing to 
 the capricious manner in which electrical forces showed 
 themselves, sometimes by attraction and sometimes by 
 repulsion. No progress could be made in this respect until 
 Dufay, a Captain in the French army, showed in the year 
 1733 that these apparently contradictory effects could be 
 explained by assuming the existence of two kinds of elec- 
 tricity, which he called vitreous and resinous, terms which 
 in our own time Lord Kelvin used in preference to the more 
 common nomenclature of positive and negative electricity. 
 Dufay's experiments attracted little attention, and Franklin, 
 two years later, formed independently a theory, which 
 admitted only one kind, but distinguished between an excess 
 and defect of that kind. Bodies were called positively and 
 negatively electrified according as they contained an excess 
 or deficiency. 
 
 Another Fellow of the Royal Society, Robert Symmer, 
 also apparently unaware of Dufay's work, revived in 1759 
 the theory of two separate kinds of electricity with opposite 
 properties, and he was for some time supposed to be its first 
 originator. He did much to promote clear and definite 
 notions on electrical matters and the merit of his investigations 
 cannot be called in question. Though the controversies 
 between the followers of Franklin and those of Dufay and 
 Symmer lasted until quite recent times, they could not lead 
 to any substantial result because there is no fundamental 
 difference between the two views. Both emphasize the 
 distinction between two opposite electrical states, and our 
 preference for one or other alternative depends mainly on 
 the ideas which we unconsciously attach to forms of expression 
 which suggest more than they are intended to do. As a 
 matter of convenience, we may think of positive and negative 
 
80 Britain's Heritage of Science 
 
 electricity without committing ourselves to any definite 
 theory as to their ultimate nature. 
 
 When the primary phenomena of static electricity had 
 been established, the further progress took its natural and 
 regular course. Experimental appliances had to be improved, 
 and instruments constructed suitable for quantitative measure- 
 ments. In this work John Canton (1718-1772), a private 
 schoolmaster, took an active and successful part. He 
 increased the efficiency of electrical machines by coating 
 the friction cushion, which was pressed against the glass 
 cylinder, with an amalgam of mercury. For the coarser 
 indicators of electricity, such as that which Gray had used, 
 Canton substituted two small spheres of pith or cork, 
 suspended from threads, which diverged when the spheres 
 became electrified. 
 
 Canton was also successful in other fields of science; we 
 owe to him the first experimental demonstration that water 
 is compressible, and the discovery of a new phosphorescent 
 body which he prepared by the action of sulphur on oyster 
 shells. William Henley, a linen-draper residing in London, 
 who reached sufficient distinction to be admitted to the 
 fellowship of the Royal Society, also constructed an electro- 
 scope intended for quantitative measurements. He was 
 chiefly interested in thunderstorms and atmospheric elec- 
 tricity generally, and noted the positive electrification of 
 the air in a dry fog. Greater importance is to be attached 
 to Abraham Bennett (1756-1799), a clergyman residing in 
 the Midland counties, who introduced the gold-leaf electro- 
 scope, the most sensitive instrument invented up to that 
 time for the detection of small quantities of electricity. 
 Simultaneously with Volta, he showed how the electric 
 condensers could be used in conjunction with electrometers 
 so as to increase their effectiveness. This led him to invent 
 an instrument called a duplicator which in principle is 
 identical with Lord Kelvin's replenisher ; but as it contained 
 conductors covered with shellac for purposes of insulation, 
 irregularities in its action interfered with the experiments. 
 In spite of these defects it was the embryo of our modern 
 " influence " machine. William Nicholson (1753-1815), to 
 whom further reference will be made (p. 107), cured most of 
 
John Canton, Henry Cavendish 81 
 
 the defects of Bennett's doubler and converted it into an in- 
 strument which ought to have come into more extensive use. 
 
 William Watson (1715-1787), who started life as an 
 apothecary, but reached sufficient distinction as a medical 
 man to obtain the honour of knighthood, improved the 
 Leyden jar by substituting tin-foil for the liquid which till 
 then had formed the inner coating. In his experiments with 
 these jars he was much assisted by Dr. John Bevis (1695- 
 1771), another medical man, who was, however, mainly 
 interested in astronomical work, and also deserves to be men- 
 tioned as being the first to make a glass containing borax, 
 and to note that its refractive power was thereby increased. 
 Dr. Ingenhouse, a Dutch doctor settled in England, conducted 
 many electrical experiments, and claimed to have been the 
 first to replace the glass cylinder used in electrical machines 
 by a disc. The same claim is, however, made by others both 
 in France and Germany, and, among Englishmen, by Jesse 
 Ramsden, the optician and instrument maker, of whom more 
 will have to be said presently, and who certainly first brought 
 glass-plate machines into general use. 
 
 On a higher plane stand the researches of Henry Cavendish 
 which now demand our consideration. A paper published 
 in the " Philosophical Transactions " contains the foundation 
 of the mathematical theory of electrostatics. There were 
 probably but few mathematicians at the time interested in the 
 subject, and the experimental part of the enquiry, which 
 might have directed more general attention to the importance 
 of the work, was not published until a century later. The 
 mathematical investigation showed that if the whole of the 
 electricity communicated to a body collects at its surface, 
 none entering the interior, it necessarily follows that the 
 repulsion between two quantities of electricity must diminish 
 with increasing distance according to the same law as that 
 of gravitation. No other law would lead to the same result. 
 Robison appreciated the importance of this investigation 
 (see p. 69), but, like others, he was ignorant of the unpublished 
 experiments which Cavendish had actually made on the 
 subject. These verified with a sufficient degree of accuracy 
 that the charge of a body in electrostatic equilibrium resides 
 at the surface, and that if any part of it penetrates into the 
 
 P 
 
82 Britain's Heritage of Science 
 
 interior, it can only be a small fraction. Fortunately the 
 manuscripts of Cavendish's electrical experiments have been 
 preserved, and were placed in the hands of Clerk Maxwell 
 when he took over the Professorship of Experimental Physics 
 at Cambridge. Their subsequent publication throws quite 
 a new light on Cavendish's importance as a physicist, giving 
 evidence of a wonderfully balanced combination of theoretical 
 power and experimental skill. Adverting to the many 
 instances in which Cavendish neglected to publish results of 
 importance, Maxwell 1 remarks : 
 
 " Cavendish cared more for investigation than for 
 publication. He would undertake the most laborious 
 researches in order to clear up a difficulty which no one 
 but himself could appreciate, or was even aware of, and 
 we cannot doubt that the result of his enquiries, when 
 successful, gave him a certain degree of satisfaction. 
 But it did not excite in him that desire to communicate 
 the discovery to others which, in the case of ordinary men 
 of science, generally ensures the publication of their 
 results. How completely these researches of Cavendish 
 remained unknown to other men of science is shown by 
 the external history of electricity. " 
 
 This is not the place to enter into the details of the various 
 researches which were edited by Maxwell in 1879. Suffice 
 it to say that Cavendish measured experimentally the 
 electrostatic capacity of bodies, anticipating Faraday in the 
 discovery of the difference of the inductive capacities of 
 various substances, and Ohm in showing that the electric 
 current is proportional to the electromotive force. He also 
 compared the electric resistance of iron with that of rain 
 water and of different salt solutions. All this was done 
 by means of a rough electroscope and without a galvanometer. 
 He converted, in fact, his nervous system into a galvanometer, 
 by comparing the electric shocks received when Leyden jars 
 were discharged through various conductors, altering the 
 length of the conductors until the shocks were estimated 
 to be equal. He obtained astonishingly accurate results 
 with such simple and almost primitive means. 
 
 1 " The Electrical Researches of the Hon. Henry Cavendish," 
 Introduction, p. xlv. 
 
Henry Cavendish 83 
 
 The second of the two electrical papers which Cavendish 
 communicated to the Royal Society attracted considerable 
 attention, and though it does not deal with any matter which 
 we should now consider of fundamental importance, it shows 
 how far Cavendish was in advance of his time in appreciating 
 electrical matters correctly. The shocks which certain fishes, 
 such as the torpedo, 1 are capable of giving to those who touch 
 them had been known for some time, and John Walsh, a 
 Member of Parliament and Fellow of the Royal Society, had 
 described some experiments showing the conditions under 
 which the shocks were received. He suggested that they 
 were of an electrical character. The idea was not generally 
 accepted, and was even laughed at on the ground that a 
 fish immersed in sea water, which conducts electricity, could 
 not be electrically charged. In answer to this objection, 
 Cavendish actually constructed an imitation torpedo and 
 demonstrated to an assembly of scientific friends the possi- 
 bility of obtaining shocks even when it was immersed in salt 
 water. 
 
 Maxwell remarks that this is the only recorded occasion 
 on which Cavendish admitted visitors to his laboratory. 
 
 Henry Cavendish was born in 1731 ; he entered Peterhouse, 
 Cambridge, in 1749, and left that University four years later 
 without taking his degree. He was elected a Fellow of the 
 Royal Society in 1760 and died in 1810. His father, Lord 
 Charles Cavendish, third son of William, second Duke of 
 Devonshire, was interested in scientific subjects and published 
 a paper on the capillary depression of mercury in glass tubes, 
 which was highly spoken of by Franklin; he was also the 
 first to construct maximum and minimum thermometers, 
 and received the Copley medal of the Royal Society for the 
 invention of these useful instruments. We may infer 
 that the mind of Henry Cavendish was first directed towards 
 science by his father's example. He lived on an allowance 
 of 500 until he was about forty years of age, when through 
 the death of an uncle he acquired a fortune which made him 
 
 1 The "word " torpedo " comes from the Italian, and is derived 
 from "torpor;" the name was given to the fish on account of the 
 numbness caused by the electric shock felt on touching it. The 
 torpedo is not now generally associated with torpor. 
 
 F 2 
 
84 Britain's Heritage of Science 
 
 one of the richest men of his time, without altering the simple 
 mode of life to which he had become accustomed. It has 
 been said of him that his chief object in life was to avoid 
 the attention of his fellows; " his dinner was ordered daily 
 by a note placed on the hall-table, and his women servants 
 were instructed to keep out of his sight on pain of dismissal." 1 
 
 There is some evidence, however, that in his intercourse 
 with scientific men he was not equally reticent. He attended 
 the meetings of the Royal Society regularly, dined nearly every 
 Thursday with the Philosophical Club, composed of some 
 of the Fellows, and in 1772 was an energetic member of a 
 committee formed to consider the best means of securing a 
 powder magazine against the danger of lightning. 
 
 Some of Cavendish's most remarkable results were de- 
 rived from experiments on gases. Such investigations then 
 tested the skill of an experimenter to a degree which is not 
 easily realized at present. To the difficulties of isolating, 
 purifying, and examining the chemical properties of these 
 invisible substances was added the mystifying belief in the 
 imaginary body, phlogiston, which was supposed to be 
 expelled hi - every act of combustion, and to account for 
 flame and fire. 
 
 From the purely experimental point of view a great 
 advance was made when gases were collected over mercury 
 instead of over water, which had been the usual practice. 
 The credit of this is due to Joseph Priestley (1733-1804), a 
 Nonconformist minister, who, having renounced his early 
 Calvinism and become a Unitarian, was then in charge of 
 Mil] Hill Chapel, Leeds ; subsequently he moved to Birming- 
 ham. Priestley held strong political views, which he expressed 
 freely, and these, together with his unorthodox opinions, 
 frequently got him into trouble. He wrote against England's 
 attitude towards the American colonies, and sympathized with 
 the French revolutionists. When he attended a dinner 
 arranged to celebrate the anniversary of the taking of the 
 Bastille, the mob burned his chapel and sacked his house. 
 He then went to live in London for a few years, but ultimately 
 emigrated to America. We owe to Priestley the discovery of 
 
 1 " Encyclopaedia Britannica." 
 
Henry Cavendish, Joseph Priestley 85 
 
 a number of gases, and he first prepared oxygen by heating 
 oxide of mercury with a burning glass. He obtained hydro- 
 chloric acid by heating spirits of salt, sulphur di-oxide 
 by the action of sulphuric acid on mercury, and ammonia 
 by heating spirits of hartshorn. Cavendish's attention was 
 attracted by an observation of Waltire, who worked with 
 Priestley, that when a mixture of hydrogen and common 
 air was fired, dew appeared on the walls of the glass 
 tubes. This was explained as being a condensation of 
 water which had been present as vapour in the original 
 gases. But Cavendish was able to prove that the water 
 formed was really the result of the combustion of oxygen 
 and hydrogen. In order to interpret correctly the lan- 
 guage in which chemists expressed their results at the 
 time we must remember that oxygen was referred to as 
 " dephlogisticated air," nitrogen as " phlogisticated air," 
 and hydrogen as " phlogiston." Cavendish therefore ex- 
 presses his result by saying " that water consisted of 
 dephlogisticated air united with phlogiston." The conclusion 
 embodies the discovery of the composition of water, which 
 till then was unknown. 
 
 Similar experiments seem to have been made by James 
 Watt, who subsequently claimed priority, but we need not 
 here enter into the discussions to which the dispute gave 
 rise, and which passed without interfering with the subse- 
 quent friendly intercourse between Cavendish and Watt. 
 
 A remarkable research originated in the interest which 
 Cavendish took in the composition of the terrestrial atmo- 
 sphere. By burning various bodies in measured volumes 
 of air, he satisfied himself that the amount of oxygen 
 present was the same in all the samples experimented upon. 
 He noticed, however, that in one of the experiments in 
 which a mixture of hydrogen and oxygen was fired by an 
 electric spark, the resulting water contained nitric acid. 
 This, Cavendish attributed to a remnant of atmospheric 
 nitrogen in the oxygen used, and, following up the matter, 
 showed that nitrogen and oxygen actually did combine 
 under the influence of an electric spark. Absorbing the 
 nitric acid formed, he could observe a shrinkage of volume 
 when sparks were passed through mixtures of nitrogen and 
 
86 Britain's Heritage of Science 
 
 oxygen. He then put himself the question, " whether 
 there are not in reality many different substances com- 
 pounded together by us under the name of phlogisticated 
 air ? " and to satisfy himself on that point, he investigated 
 whether the whole of the air could be transformed into 
 nitric acid by combination with oxygen. He found that 
 there was, indeed, a small portion, estimated by him as 
 y^-o of the whole, which resisted the change. This remnant 
 undoubtedly consisted of argon, a separate gas, identified as a 
 new element only in our own times. The amount of argon 
 actually present in the air agrees remarkably well with 
 Cavendish's estimate of his residual gas. 
 
 There are many investigations on heat, unpublished at 
 the time, by which Cavendish anticipated Black in the 
 discovery of latent heat; he also determined the specific 
 heats of a number of bodies. Another important research 
 remains to be noted. A Yorkshire clergyman, John 
 Michell, had conceived the brilliant and ambitious idea of 
 measuring directly the gravitational attraction between two 
 spheres of lead. It has already been remarked, in con- 
 nexion with the Schehallien experiment of Maskelyne and 
 Hutton, that the average density of the earth may be 
 derived from such a measurement, but quite apart from 
 this application, the attempt to demonstrate Newton's 
 gravitational force within the four walls of a room con- 
 stitutes an effort of heroic ambition and remarkable fore- 
 sight. John Michell had constructed all the necessary 
 apparatus, including the torsion balance, which he had 
 invented for the purpose. Infirmities of age prevented his 
 carrying out the work, and at his death the apparatus fell 
 into the hands of another distinguished clergyman, Francis 
 John Hyde Wollaston (brother of the celebrated chemist), 
 who, at the time, held the Jacksonian Professorship at 
 Cambridge. Wollaston deserves considerable credit for 
 handing over the execution of the experiment to the one 
 living man who was capable of bringing it to a successful 
 issue. The original torsion balance consisted of a wooden 
 beam about two yards long, weighing 5J ounces, and 
 carrying at each of its ends a leaden sphere two inches in 
 diameter. Cavendish substituted for the beam a metal rod 
 
J 
 
 John Clerk Maxwell 
 
 From an engraving in "Nature " 
 by G. J. Stodart of a photograph 
 
 hv FP.Y&US ni Crl.fi.<icrniti 
 
John Michell 87 
 
 strengthened by a copper wire which acted as a tie to pre- 
 vent bending, and was attached to a vertical suspension. 
 
 On being slightly displaced from its position of equili- 
 brium the torsion of the wire by which it was suspended 
 would tend to bring the horizontal beam back and make 
 it oscillate slowly in a horizontal plane. Two larger leaden 
 spheres eight inches in diameter could be brought near the 
 ends of the beam, so that their gravitational attraction 
 on the spheres attached to the beam would displace it, 
 with the result that it would oscillate about the new posi- 
 tion of equilibrium. By bringing the larger spheres round 
 to the other side of the beam the displacement in the 
 opposite direction could be observed and the gravitational 
 effect measured. Cavendish fully realized the difficulties 
 he would have to encounter in consequence of almost 
 unavoidable air currents. Even when the apparatus was 
 enclosed in a box the slightest difference in temperature 
 would cause convection currents and, consequently, irre- 
 gular movements of the beam. He, therefore, had to plan 
 out a scheme which would allow him to conduct the whole 
 of the experiments without entering the room in which 
 the apparatus was placed. The observations were taken, 
 and the large leaden spheres moved one side of the beam 
 to the other from outside. No more delicate measurement 
 had ever been successfully carried out. From the average 
 of the number of observations, Cavendish deduced the 
 value of 5*48 for the density of the earth, a number in fair 
 agreement with, though slightly larger than, that obtained 
 by Maskelyne and Hutton. The extreme difficulty and 
 great charm of the experiment has still in our times 
 attracted the most skilled physicists, and the introduction 
 of quartz fibres by Mr. Vernon Boys has enabled us to 
 increase its accuracy considerably. The final value for the 
 average density of the earth as determined by Mr. Boys 
 is 5-5270, so that Cavendish was correct to within one per 
 cent. 
 
 John Michell (1724-1793), whose name has been mentioned 
 above as the inventor of that most useful and delicate 
 appliance, the torsion balance, has also in other directions 
 given evidence of great originality of mind. He contributed 
 
88 Britain's Heritage of Science 
 
 an important paper entitled " Conjectures concerning the 
 cause and observations upon the phenomena of earthquakes " 
 to the Philosophical Transactions of the Royal Society, 
 and was the first to suggest that double stars were more 
 likely to be systems of physically connected bodies than 
 accidental coincidences in the directions of two stars which 
 might be at great distances one behind the other. This, as 
 will presently appear, was subsequently proved by William 
 Herschel to be the case. 
 
 It is not surprising that astronomy has always been a 
 favourite study of men of leisure, with a scientific turn of 
 mind. As Tyndall, in one of his lectures, said, we are most 
 impressed by what is either exceptionally large or excep- 
 tionally small; and the feeling that in examining the 
 heavens, our laboratory, no longer confined to a few cubic 
 feet, extends through the universe, fascinates the human 
 mind. Added to this, useful work can be carried on in 
 astronomy with comparatively simple though sometimes 
 expensive appliances, and to the painstaking, but not 
 perhaps, mathematically inclined enthusiast, special pro- 
 blems are often ready to hand, which depend on accurate 
 registration rather than on extensive knowledge. When, 
 as not infrequently happens, the power of dealing with 
 the observations is added to the aptitude for observation, 
 the amateur can rise to the level of the professional more 
 easily than in most other subjects. 
 
 It is impossible to say what position Jeremiah Horrocks 
 (1619-1641) might have attained had his life not been 
 cut short so early. He died at the age of twenty-two, with 
 a remarkable record to his credit. After passing through 
 Emmanuel College, Cambridge, as a sizar, he earned his 
 living as a teacher at his native place, Toxteth Park, near 
 Liverpool. Through William Crabtree, a wealthy draper 
 of Manchester, whose acquaintance he had made, he became 
 interested in astronomy, and on his advice studied the 
 works of Kepler. Having tested and corrected the tables 
 giving the positions of planets which had been published 
 by that astronomer, he formed the conclusion that a transit 
 of Venus would occur on the 24th November 1639. This 
 happened to be a Sunday, and Horrocks being at that 
 
J. Horrocks, S. Molyneux 89 
 
 time a curate at Hoole was afraid that clerical duties would 
 prevent his observing the transit. He, therefore, asked 
 his friend Crabtree to watch independently for the appearance 
 of Venus on the solar disc. Fortunately, Horrocks was 
 set free before the planet had crossed the sun, and he 
 could follow its passage until the time of sunset. This was 
 the first time that human eye had witnessed this rare 
 occurrence. Among the frescoes by Madox Brown in 
 the Town Hall of Manchester one represents this transit 
 of Venus. Unfortunately, the pictures being intended to 
 commemorate events in the history of Manchester, the 
 scene is laid in that city, and Crabtree is made to be the 
 central figure, conveying a wrong impression of a great 
 historical event. 
 
 The papers left by Horrocks were preserved by Crabtree 
 and ultimately published. They show that he had the 
 making of a great man of science in him. Before he was 
 twenty, he showed how Kepler's laws had to be modified 
 in order to fit the motion of the moon, and he suspected 
 that these modifications were due to some disturbing cause 
 emanating from the sun, as Newton afterwards proved was 
 actually the case. He also discovered certain irregularities 
 in the motions of Jupiter and Saturn, now known to be due 
 to their mutual attractions. 
 
 The name of Molyneux first appears in this country at 
 the time of the Norman Conquest through William de 
 Moline, from whom the Earls of Sefton are descended. 
 Another family of the same name is derived from Sir Thomas 
 Molyneux, who came over from France, settled in Ireland, 
 and became Irish Chancellor of the Exchequer. One of 
 his great grandsons was Sir Thomas Molyneux, physician 
 and zoologist, another William Molyneux, a philosopher, 
 politician, and astronomer. Several of his papers were 
 published in the Transactions of the Royal Society. They 
 deal with the erecting eyepiece of terrestrial telescopes, 
 the tides and the causes of winds; he also pointed out 
 errors which occurred in surveying through neglecting to 
 take account of the secular variation of the magnetic 
 declination. 
 
 Samuel Molyneux (1689-1728), the son of William, 
 
90 Britain's Heritage of Science 
 
 followed in his father's footsteps as astronomer, and built 
 himself an observatory at Kew. It was here that the 
 observations which led to the discovery by Bradley of the 
 aberration of light were carried out. Molyneux has not re- 
 ceived sufficient credit for the design of the instrument and 
 of the measuring appliances on which the successful prosecu- 
 tion of the research depended. The idea of testing Hooke's 
 method of measuring the so-called " parallax " of stars 
 seems to have been due to Molyneux. He worked assiduously 
 at the construction of telescopes, one of which he presented 
 to the King of Portugal, and left an unpublished MS. on 
 optics, which was made use of by Robert Smith in the 
 preparation of his treatise. 
 
 The work of William Herschel (1738-1822) brings us 
 into touch with modern astronomy. His father was a 
 musician in the Hanoverian Army, though the family 
 originally came from Moravia. At the age of fourteen he 
 accompanied, as an oboe player, a Hanoverian band on a 
 visit to England, but only settled finally in this country 
 in 1757, his health not being strong enough to take part 
 in the Seven Years' War. He ultimately went to live in 
 Bath as a teacher of music, and became director of the 
 musical entertainments in that fashionable resort. His 
 turn for reading serious books led him to the study of 
 Ferguson's astronomy and Smith's harmonics, followed by 
 the optics of the same writer. He then decided to take up 
 astronomy more seriously; he bought a small Gregorian 
 telescope, but not content with this, and, unable to obtain 
 a larger instrument with the means at his disposal, he set to 
 work with his own hands, and having succeeded in polishing 
 a mirror of six-foot focal length mounted it as a reflecting 
 telescope. A frequently quoted passage from one of his 
 letters, written in 1783, shows the object he had in view : 
 " I determined to accept nothing on faith, but to see 
 with my own eyes what others had seen before me. I 
 finally succeeded in completing a so-called Newtonian in- 
 strument, seven feet in length. From this, I advanced 
 to one of ten feet, and at last to one of twenty, for I had 
 fully made up my mind to carry on the improvement 
 of my telescopes as far as it could be done. When I 
 
William Herschel 91 
 
 had carefully and thoroughly perfected the great instru- 
 ment in all its parts, I made systematic use of it in my 
 observations of the heavens, first forming a determi- 
 nation never to pass by any, the smallest, portion of 
 them without due investigation." 
 
 Even the largest of the instruments, mentioned in this 
 letter, did not satisfy him, and he determined to improve 
 upon it by constructing one of twice its size. This was 
 finally mounted at Slough, where he had settled with his 
 sister in 1782. The polishing of concave mirrors was at 
 that time a serious business. On one occasion he kept 
 the tool on the mirror continuously for sixteen hours, and 
 with both hands engaged had to be fed by his sister, Caro- 
 line, who then kept house for him. His desire to obtain 
 larger and larger instruments did not, however, prevent 
 Herschel from making good use of those he had completed. 
 Surveying systematically the whole of the heavens he was 
 soon rewarded by a brilliant discovery. 
 
 Struck by the peculiar appearance of a star that crossed 
 his field of view, he examined it with higher magnifying 
 powers, and found its apparent disc increased. Two days 
 later, a slight change of position could be detected. At 
 first it was thought to be a comet, but, ultimately, Saron, 
 at Paris, and Lexell, at Petrograd, found that its path in- 
 dicated an orbit round the sun of a nearly circular shape. 
 It then took its place as a new planet, the first that had 
 been discovered in historic times. The name " Georgium 
 Sidus," suggested by Herschel, was not generally accepted, 
 and was subsequently replaced by " Uranus." The dis- 
 covery was a fortunate one for Herschel, as it established 
 his reputation, and, what was more important, led 
 George III. to appoint him his private astronomer, with 
 a salary which, though modest, set him free to give up 
 his professional work and devote his entire energies to 
 astronomy. For a time, he increased his income by making 
 and selling telescope mirrors, but this ceased to be necessary 
 when, a few years later, he married a lady of independent 
 means. 
 
 The leading feature of Herschel's work was his strong 
 faith in the unity of design which he tried to trace in the 
 
92 Britain's Heritage of Science 
 
 structure of the Universe. He looked upon the assemblage 
 of stars as an organic whole, and endeavoured to find 
 regularities in their distribution or arrangement. He thus 
 opened out an entirely new branch of enquiry. 
 
 If stars were scattered at random, we should find on 
 the average an equal number in all parts of the sky. In 
 order to avoid the enormous and practically impossible 
 labour of actually counting the total number of stars 
 visible in his telescope, Herschel devised a method of 
 gauging the heavens, which gave him sufficiently good 
 average results. This consists in taking specimens, by 
 counting the stars which appear in a number of single fields 
 of view near together, and taking the average number of 
 stars recorded as an index of the density in this particular 
 region of the heavens. It is obvious that the number of 
 stars is vastly greater in the Milky Way than anywhere 
 else, and the question arose whether that dense conglo- 
 meration had any relation to the rest of the stellar universe. 
 It was, therefore, a discovery of the greatest interest and 
 importance to find that the stars throughout the heavens 
 increase in density as we approach the region of the Milky 
 Way, thus demonstrating that the visible universe is not an 
 accidental jumble, but possesses an organized structure. 
 
 Results, of equal interest, were obtained from the close 
 investigations on double stars, of which about forty were 
 known when Herschel began his work. Having added 
 nearly 400 to this number, he set out to measure the relative 
 positions of the two components of each doublet, and, 
 repeating the measurements from time to time, discovered, 
 after twenty years of work, that some of these double stars 
 are physically connected, consisting of two huge and 
 luminous masses which revolve round each other. 
 
 The organic bond which connects the separate units of 
 the universe revealed itself in a striking manner, by Halley's 
 discovery already referred to, that many of the stars are 
 apparently moving through space with considerable velo- 
 cities. Examining the direction and magnitude of the 
 observed shifts, Herschel noticed that if the average motion 
 be taken in any one region, that average is nearly the 
 same in different parts of the sky. As our observations 
 
William Herschel 93 
 
 can only indicate a motion relative to the earth, we must 
 conclude that if we consider the system of stars as a whole 
 to be at rest, our sun with its planetary system moves 
 towards a definite point in the heavens. If, on the other 
 hand, we consider the solar system to be at rest, then the 
 great majority of stars are drifting in nearly parallel 
 directions, and whatever view we may take it is certain that 
 the star velocities are not entirely independent of each 
 other. The subject is one that has received renewed 
 attention in recent years; it has now been demonstrated 
 that there is more than one star-drift, and Herschel's work 
 is likely to develop into an important -department of 
 astronomy. 
 
 One further discovery of considerable interest and im- 
 portance but belonging to the domain of physics, remains 
 to be noted. In order to compare the heating effects 
 of the coloured rays of which, as Newton taught us, solar 
 light is composed, Herschel placed thermometers in the 
 different portions of a spectrum obtained by means of a 
 prism. He noted that the heating powers of the rays 
 continuously increased from the blue through the green 
 and yellow to the red. He then discovered that the 
 thermometer rose highest when placed outside the red, 
 proving that the solar spectrum contains invisible rays less 
 refrangible than the red. These rays, though they do not 
 affect our eye, become apparent by means of then* heating 
 effect. Herschel satisfied himself that these invisible rays 
 were refracted and reflected according to the ordinary laws. 
 
 The idea of invisible radiations, refrangible like light at 
 the surface of transparent bodies was at that time entirely 
 novel, and must have appeared almost as surprising as the 
 discovery of Roentgen rays in our own time. The heat 
 radiations were at first looked upon with scepticism, and 
 met with opposition in some quarters, even when Wollaston 
 soon afterwards proved the existence of other rays beyond 
 the violet end of the spectrum which showed themselves by 
 their chemical effects. 
 
 The success of experimental investigation depends so 
 much on the use of scientific instruments and appliances 
 that the important share contributed to the progress of 
 
94 Britain's Heritage of Science 
 
 science by the designers and makers of instruments deserves 
 to be emphasized. Improvements in the design of an instru- 
 ment lead not only to increased accuracy but also to the 
 saving of time and labour, which is frequently of equal 
 importance ; and in this connexion we need not necessarily 
 think of the construction of the costly instruments which the 
 astronomer now requires, nor of the elaborate appliances 
 to be found in a modern physical laboratory. The most 
 effective instrumental improvements have frequently been 
 of the simplest kind, and a handy appliance, such as the 
 slide rule, saves an amount of time which in the aggregate 
 may sum up to an astonishing figure. The slide rule was 
 introduced at a surprisingly early time. Almost immediately 
 following the introduction of logarithms, Gunter constructed 
 a rod with logarithmic divisions engraved on it, but its use 
 involved the application of a pair of dividers. The sliding 
 arrangement which is the essential feature of the appliance 
 was first used by Oughtred (1575-1660), a mathematically 
 inclined clergyman, who incidentally introduced the X sign 
 for multiplication and the symbol : : for proportion. 
 
 There is no department of science that depends on 
 instrumental appliances more than astronomy. The con- 
 struction of mirrors and lenses, the improvement of clocks 
 and the accurate angular division of measuring circles all 
 require skilled labour of the highest kind, while the require- 
 ments of navigation severely test the ingenuity of the 
 inventor, who has to simplify the instruments and make 
 their working independent of that firm support which may 
 be obtained on dry land, but is not available on board ship. 
 
 As an instrument of precision the telescope was almost 
 useless until some measuring arrangement was introduced. 
 A micrometer eyepiece consisting of two metallic edges, 
 the distance between which could be altered and measured 
 by a screw, was invented by a young astronomer, William 
 Gascoigne, a friend of Jeremiah Horrocks and Crabtree, born 
 about 1612, and killed in the battle of Marston Moor. The 
 Gascoignes are first mentioned in English history when Sir 
 William Gascoigne acted as Chief Justice in the reign of 
 Henry IV., and his son, George, acquired the reputation 
 of a poet, but it is not known whether the astronomer 
 
W. Oughtred, J. Hadley, G. Graham 95 
 
 descended from them. Crabtree mentions the invention of 
 the micrometer in a letter to Horrocks, and the instrument 
 itself was exhibited by Townley at a meeting of the Royal 
 Society in 1667. Unfortunately it escaped the notice of 
 astronomers until Huygens had constructed a similar but 
 less perfect appliance, and Adrien Angout had produced a 
 micrometer in which Gascoigne's edges were replaced by 
 silk fibres. 
 
 If one had to select the instrument which combines the 
 greatest simplicity with the highest precision, there is little 
 doubt that one's choice would fall on the sextant, the most 
 perfect appliance that has ever been invented. It is mainly 
 used on board ship, but it has been successfully employed 
 in the United States for accurate surveys on land. No one 
 who has not held a sextant in his hand, and seen how, after 
 a few days' practice, he could determine the local time to 
 the tenth part of a second, and the latitude to a few hundred 
 yards, can realize the beauty of the instrument and the sense 
 of power it gives to its user. The inventor, John Hadley, 
 was an instrument maker about whose life very little is 
 known, though the Royal Society recognized his merits by 
 electing him to their Fellowship, and ultimately made him 
 a Vice -President. His instrument, the circle of which only 
 covered 45, and which therefore ought more properly to ba 
 called an " octant," was first shown to the Royal Society 
 in 1744. Hadley also revived the use of reflecting telescopes ; 
 the construction of which had shown little progress since 
 Newton's time. 
 
 The accuracy of astronomical observations depends in 
 many cases on the excellence of the timekeepers employed 
 to record the instant at which a star passes the centre of 
 the telescopic field of view. Clocks used for the purpose 
 are regulated by the swing of a pendulum acting through a 
 mechanism called an escapement. The first efficient appli- 
 ance of its kind, the anchor escapement, was invented by 
 Robert Hooke, and improved upon by George Graham 
 (1675-1751), an ingenious clockmaker who was generally 
 interested in scientific matters. We owe to him, e.g., the 
 discovery of the diurnal variation of terrestrial magnetism. 
 In the construction of clocks he introduced an important 
 
96 Britain's Heritage of Science 
 
 improvement. Owing to the expansion and contraction of 
 ordinary materials when the temperature rises or falls, the 
 time of oscillation of an ordinary pendulum alters with every 
 change of temperature ; but by properly combining different 
 materials, the difficulty may be overcome. Graham attached 
 a cylindrical vessel partly filled with mercury to the bob of 
 the pendulum; when the rod of the pendulum expands the 
 support of the mercury vessel descends, but the mercury 
 in the vessel also expands, which tends to raise the centre 
 of gravity of the whole arrangement. The expansion of 
 the mercury being considerably greater than that of the 
 pendulum rod, its volume may be adjusted so that the two 
 actions counterbalance each other, and the pendulum may 
 be made independent of moderate changes of temperature. 
 Another arrangement, the " gridiron " pendulum, was intro- 
 duced by John Harrison (1693-1776), the son of a York- 
 shire carpenter, who became a surveyor, and settled down 
 in London as a watchmaker. His pendulum compensation 
 has been very extensively used, but Harrison will chiefly 
 be remembered as the inventor of the chronometer. 
 
 The demand for accurate timekeepers suitable for use on 
 board ship had become so urgent a question at the time, that 
 the Government had offered a reward of 20,000 to anyone 
 who would produce an instrument which satisfied certain 
 requirements. Harrison soon supplied a te time-measurer " 
 or " chronometer " which promised so well that the Govern- 
 ment helped him with grants of money and facilities for 
 testing his instrument on sea journeys. But it took him 
 twenty-six years of continued labour before he obtained the 
 full reward, producing a chronometer which, on a journey 
 to Jamaica and back, showed an accumulated error of less 
 than two minutes; this satisfied the required conditions, 
 and the prize was awarded to him. One of the features of 
 Harrison's chronometer, showing great ingenuity and manipu- 
 lative skill, consisted in the temperature compensation which 
 was applied to the balance wheel. 
 
 Next to accurately going clocks, the astronomer requires 
 well-divided circles for the measurement of angles. Three 
 English instrument makers secured considerable reputation 
 in this work during the eighteenth century. The first of 
 
John Harrison, Jesse Ramsden 97 
 
 these, Graham, whose name has already been mentioned in 
 connexion with clocks, worked for Halley and Bradley at 
 Greenwich, and supplied an instrument to the Paris Academy 
 of Sciences. The second, John Bird (1709-1776), divided 
 a number of quadrants for several public observatories, and 
 his method of working was considered so good that the 
 Government purchased the right of employing it. 
 
 Further improvements were introduced by Jes^e Ramsden 
 (1735-1800), the son-in-law of John Dollond, who designed 
 an engine for dividing mathematical instruments and re- 
 ceived a premium for 315 from the Government for this 
 invention. Ramsden was a remarkable man. The son 
 of an innkeeper at Halifax, he became a clerk in a cloth- 
 maker's warehouse, after having completed a three years' 
 apprenticeship. Two years later, when twenty-three years 
 old, he again apprenticed himself, this time with a mathe- 
 matical instrument maker, and afterwards established him- 
 self independently. His shop, first opened in 1762, in the 
 Haymarket, was transferred later to Piccadilly. He soon 
 acquired fame for the excellence of his workmanship, and 
 we are told that, though ultimately sixty workmen were 
 employed by him, the demand from all parts of Europe for 
 his instruments was greater than could be satisfied. He 
 was highly successful in constructing a new equatorial 
 mounting for telescopes and a clockwork which drove the 
 mirror of a siderostat so accurately that a star could be 
 followed for twelve hours ; but it was his skill in dividing circles 
 to which he mainly owed his great reputation. There can 
 be no doubt that his practice of substituting entire circles 
 for the usual quadrants and sectors was sound in principle 
 and contributed much to his success. Every student of 
 optics knows " Ramsden's eyepiece," and he also invented 
 a double image micrometer. The Royal Society recognized 
 his work by awarding him the Copley medal in 1795. 
 
 While clocks and divided circles are necessary parts of 
 an astronomer's equipment, he depends primarily on the 
 optical performance of his telescopes. Newton had used 
 mirrors to focus the beams of light, as he considered it 
 to be impossible to do so accurately by means of lenses, 
 because rays of different colours, being refracted to a different 
 
98 Britain's Heritage of Science 
 
 degree in their passage through a lens, come to a focus at 
 different points. Hence the images formed by simple lenses 
 of glass are coloured. Though the possibility of combining 
 several lenses made of different materials had occurred to 
 Newton, he had come to the conclusion that the dispersive 
 power of substances (which is the power to separate different 
 colours), is proportional to their refractive power, and if 
 this were really the case, it would indeed be impossible to 
 construct a lens which could bring different coloured rays 
 to the same focus. The succeeding history of the subject is 
 interesting. Euler asserted that notwithstanding Newton's 
 experiments, which he accepted, it should be possible to 
 produce achromatism, i.e., images without coloration, by 
 means of a combination of lenses. David Gregory had 
 already in 1695 expressed similar ideas, and their argument 
 depended on the belief that the images formed by the human 
 eye are not deteriorated by any colour-dispersion. As the 
 rays entering the eye are concentrated on the retina by 
 successive refraction through different media, such as the 
 cornea, the crystalline lens and the vitreous humour, it 
 was argued that it should be possible to produce achromatic 
 images by properly combining lenses of different materials. 
 Euler's belief that the optical arrangement of the eye pointed 
 the way to the construction of achromatic lenses was shared 
 by others, and ultimately led to the solution of the problem ; 
 but the curious point is, that the premise on which the whole 
 argument depends is wrong, the eye not being achromatic 
 at all, but subject to the same defects as a simple lens. 
 
 A Swedish mathematician, Klingenstjerna, seems to have 
 been the first to repeat Newton's experiments with sufficient 
 care, when it appeared that the relationship between 
 refractive and dispersive powers, which Newton thought 
 he had established, did not hold accurately. John Dollond 
 (1706-1761), a son of one of the many French refugees who 
 came to England after the revocation of the Edict of Nantes, 
 had started life as a silk weaver in Spitalfields, but relin- 
 quished this occupation and established a workshop for 
 optical instruments. Having heard of Klingenstjerna's obser- 
 vation, he entered into an independent investigation on the 
 optical properties of different kinds of glass, and had the 
 
John Dollond, Edward Somerset 99 
 
 satisfaction of solving, at last, this most important problem. 
 By combining two lenses of different kinds of glass, he could 
 produce images in which the colour defect was, though not 
 entirely abolished, yet very materially diminished. In this 
 discovery he was, however, anticipated by Chester More 
 Hall of More Hall in Essex, a barrister, who, in 1833, had 
 already succeeded in constructing an achromatic lens. 
 Dollond's patent was subsequently challenged on the ground 
 of anticipation, but the judgment was upheld in favour of 
 Dollond on the ground containing much common sense 
 that " it was not the person who locked his invention in his 
 scrutoire that ought to profit from such invention, but he 
 who brought it forth for the benefit of mankind." 
 
 The improvements effected in electrical appliances by 
 Canton, Henley, Bennett and others have already been 
 described, and we may therefore pass on to the more direct 
 applications of scientific principles to the utilization of power. 
 The early steam engines we should hardly call them by 
 that name now were little more than toys, useful, perhaps, 
 for the special purpose for which they were designed, but 
 wasteful and costly in their working. It was only when 
 James Watt came to apply the scientific methods acquired 
 in his intercourse with Joseph Black and John Robison 
 that an efficient machine could be evolved. 
 
 We may begin our account of the history of steam 
 engines with Edward Somerset, Marquis of Worcester, 
 whose romantic personality and tragic history form an 
 interesting study. He claims to have accomplished some 
 wonderful things in a publication that bears the eccentric 
 title : "A century of the names and skantlings of such 
 inventions as at present I can call to mind to have tried 
 and perfected, which, my former notes being lost, I have 
 at the instance of a powerful friend endeavoured, now in 
 the year 1655, to set down in such a way as may sufficiently 
 instruct me to put any of them in practice." But his 
 descriptions are so fantastic and vague that doubts have 
 been raised whether he had ever gone beyond the forming 
 of plans and making of projects, leaving the rest to his 
 imagination, which had ample scope to exercise itself 
 during a six years' confinement in the Tower of London. 
 
 G 2 
 
100 Britain's Heritage of Science 
 
 We possess, however, the testimony of an eye-witness who 
 had seen near Vauxhall one of Worcester's machines raise 
 water through a height of forty feet. Engines were chiefly 
 wanted at the time for the pumping of water, more 
 especially to clear the mines, and it is therefore, not sur- 
 prising that the first practical application of the pressure 
 provided by steam should have been made by a miner. 
 Thomas Savery's (1650?-1702) machine probably resembled 
 that of Worcester, and it is immaterial whether it was 
 an independent invention or not. A short description may 
 serve to illustrate its mode of work. A cylindrical vessel 
 has three tubes leading out of it, each capable o ; being 
 opened and closed by a stopcock. The first tube joining 
 the upper end of the cylinder is connected with a boiler; 
 the second (the inlet tube) leads from the bottom of the 
 cylinder vertically downwards to a reservoir of water, and 
 the third (the out'et tube), also connected to the bottom of 
 the cylinder, is bent round so as to lead vertically upwards. 
 To start the machine, the cylinder is filled with water, and 
 the stopcock of the inlet tube closed, while the two others 
 are opened. Steam is then admitted, and the water expelled 
 through the outlet tube. When the whole cylinder is filled 
 with steam the boiler and outlet tubes are closed, and the 
 inlet tube opened. The cylinder is cooled and the vacuum 
 formed by the condensation of the steam draws a supply 
 of water from the reservoir upwards into the cylinder. 
 When the cylinder is filled, the stopcock of the inlet tube 
 is closed, and the process repeated. The height to which 
 the water may be raised in this manner depends on the 
 pressure of steam employed, which in Savery's engine 
 reached up to eight or ten atmospheres, corresponding to 
 a height of about 250 feet of water. It will be seen that this 
 machine contains no piston such as we associate now with 
 steam engines, and there is no mechanical transmission of 
 motion. Its sole object is the raising of a weight of water 
 by the pressure of steam. 
 
 Papin (1647-1714), a French Calvinist who had to leave 
 his country on account of his religious opinions, lived in 
 England for some time, but ultimately accepted a pro- 
 fessorship in a German University. He suggested the use of 
 
T. Savery, D. Papin,'T. N^wconien'- ^ 
 
 a piston, but abandoned the idea in favour of a modified 
 form of Savery's engine. 
 
 During his stay in England, Papin took an active part 
 in the Proceedings of the Royal Society, and in 1684 was 
 appointed temporary curator of that body with a salary 
 of 30, in consideration of which he was required to pro- 
 duce an experiment at each meeting of the Society. He 
 had invented a so-called " bone-digester," to which Evelyn 
 in his diary refers in these terms : " The hardest bones of 
 beef itself and mutton were made as soft as cheese, without 
 water or other liquor, and with less than eight ounces of 
 coal, producing an incredible quantity of gravy; and, for 
 close of all, a jelly made of the bones of beef, the best for 
 clearness and good relish, and the most delicious that I 
 have ever seen or tasted." Papin kept up his correspondence 
 with the Royal Society after settling in Germany, sub- 
 mitting to them a proposal to apply a steam engine to the 
 propulsion of ships, and asking for a grant of 15 for his 
 " expense, time and pain " in putting his ideas to the test. 
 Papin is also credited with the invention of the safety 
 vaive. 
 
 The next successful step in the construction of steam 
 engines was taken by Thomas Newcomen (1663-1729), an 
 ironmonger of Dartmouth, who seems to have entered into 
 correspondence on the subject with Robert Hooke, and, 
 together with Cawley, another tradesman of his native 
 town, produced a machine which in several ways was better 
 than its predecessors. He introduced a cylinder with a 
 piston that could be raised by the pressure of steam, the 
 piston rod being mechanically connected with a pumping 
 arrangement. The steam was condensed in the cylinder 
 itself by a jet of water, and the work was mainly performed 
 in the downward stroke, when the atmospheric pressure of 
 air pressed the piston down into the vacuum formed inside 
 by the condensation of steam. Newcomen's engines came 
 into general use for the pumping of water. 
 
 In all the attempts made so far, no consideration is given 
 to the economical use of fuel, a disadvantage which was 
 severely complained of by those who used the engines. 
 A new era began with the work of James Watt (1736-1819 
 
102- Britain' 3 Heritage of Science 
 
 We are all familiar with the story which tells how as a boy 
 he watched the steam escaping from a tea-kettle, and dreamt 
 of the future of steam-power. Such tales about precocious 
 signs of future greatness may have a psychological interest 
 when they are well authenticated, and given in the correct 
 perspective of surrounding circumstances ; but even then 
 we should not be able to estimate their true value unless 
 we knew how many boys watched tea-kettles and made 
 acute remarks without growing up to be great men. 
 When we are told, for instance, of another eminent man 
 who as a boy was asked to see what time it was, and returning 
 after looking at the clock, said : "I can't tell you what 
 time it is now, but when I looked at the clock it was ten 
 minutes past three," we are tempted to ask what proportion 
 of the boys who could give such an answer became great 
 mathematicians, and how many merely great prigs. The 
 story of Watt's tea-kettle rests on a memorandum dictated 
 by an oldiady, a cousin of his, fifty years after the occurrence, 
 but the most significant part of her account is not generally 
 mentioned. It was not the power of steam that Watt was 
 watching, but the condensation into water when the steam 
 came into contact with a silver spoon. The incident may 
 be accepted as a sign of a scientific and enquiring mind, 
 perhaps as a token of his interest in the properties of steam, 
 but not as a forecast of his future belief in the powers 
 of steam. James Watt came from a family of mathe- 
 maticians. His grandfather, Thomas Watt, was a teacher 
 of navigation, and his tombstone bears the title : " Pro- 
 fessor of Mathematics." His father was a shipwright, 
 supplying vessels with nautical instruments, and a mechanic. 
 In the latter capacity he made and erected, for the use of 
 Virginia tobacco ships, the first crane ever seen at Greenock. 
 Growing up in these surroundings, Watt at an early age 
 became familiar with the use of tools, and set up a small 
 forge for himself for the making and repairing of instru- 
 ments. He left his Scotch home and became apprenticed 
 to an instrument maker in London, but bad health obliged 
 him to return at the end of the year. When his attempt 
 to set up a shop at Glasgow was objected to by the guilds, 
 because he had not served his full apprenticeship, the 
 
James Watt 103 
 
 difficulty was overcome by some of the professors who 
 had recognized his ability before he went to London, and 
 established him as instrument maker to the University. 
 This gave Watt the opportunity of entering into intimate 
 scientific intercourse with such men as Joseph Black and 
 John Robison, and gaining a knowledge of the scientific 
 principles of heat. 
 
 It was only in 1764, when a working model of one of 
 Newcomen's engines was sent to Watt for repair that his 
 mind was directed to the potential value of these machines. 
 Watt at once recognized the cause of the enormous waste 
 of fuel which constituted the chief defect of the engine. 
 When the steam introduced into the cylinder had done its 
 work by raising the piston, it had to be condensed before 
 the piston could return; this was done by a jet of cold 
 water introduced into the cylinder, which, of course, did 
 not only condense the steam but also cooled down the mass 
 of metal which formed the walls of the cylinder. When 
 the steam was reintroduced, the whole had to be raised up 
 again to the temperature of the steam before the piston 
 could be lifted. In order to avoid this waste of heat Watt 
 saw that the cylinder ought to be maintained permanently 
 at the temperature of the steam, and for this purpose it 
 became necessary to condense it, not in the cylinder itself, 
 but in another vessel, into which it had to be driven after 
 it had done its work. The invention of this separate con- 
 denser was Watt's first contribution to the steam engine. 
 He settled down in Birmingham with Matthew Boulton, 
 a capitalist, and gained experience in the manufacture of 
 his improved machines, which were still used exclusively 
 for pumping water. 
 
 The next great step was made in 1782. Up to that date 
 steam was only admitted to the cylinder on one side of the 
 piston, the return stroke being made by the pressure of the 
 air against the vacuum formed by the condensation of steam. 
 Watt now invented the double-acting engine, in which 
 steam is alternately admitted and acts on both sides of the 
 piston. The third advance, which brings us still nearer to the 
 modern engine, is due mainly to the scientific knowledge 
 which Watt had gained of the properties of steam, investi 
 
104 Britain's Heritage of Science 
 
 gating for. himself the connexion between its temperature, 
 density, and pressure. Instead of allowing the steam to 
 pass into the cylinder during the whole of the stroke, Watt 
 saw that a considerable economy could be effected by 
 stopping the admission when the stroke had reached a 
 certain point and allowing the pressure of the steam already 
 in the cylinder to complete it. It is not necessary to enter 
 further into the many improvements of detail which the 
 steam engine owes to Watt, who, realizing the future that 
 was before it, also devised various means by which the up 
 and down stroke of the engine could be converted into 
 rotatory motion. 
 
 Savery is said to have been the first to suggest that the 
 measured power of performance of an engine might be in 
 terms of horse-power, but Watt actually investigated the work 
 that a horse could do in a given time, and defined one horse- 
 power as the rate at which work is done when 33,000 Ibs. 
 are raised one foot in one minute. 
 
 Watt was of a retiring disposition, due, no doubt, to 
 the weakness of health which, in the early part of his life, 
 greatly interfered with his work. He speaks of himself as 
 " indolent " and " not enterprising," and as being " out 
 of my sphere when I have anything to do with mankind." 
 His inventions were not confined to the steam engine. He 
 constructed a press for copying manuscripts, such as is now 
 in common use. It is also claimed on behalf of Watt, 
 and with some justification, that he was the first to discover 
 the true composition of water as a compound of oxygen 
 and hydrogen. The controversy which arose has already 
 been referred to (page 85). 
 
 The condenser used by Watt can be easily attached to 
 stationary engines, but is inconvenient when an economy 
 of space is imperative, as when steam is used for road 
 propulsion. The condenser may then be dispensed with, 
 but the pressure of steam has to be increased. Richard 
 Trevithick (1771-1833), whose father was the manager of a 
 Cornish mine, invented a road locomotive with high pressure 
 steam, and conveyed passengers with it on Christmas Eve, 
 1801. Some sort of steam vehicle had, however, already 
 been built in France by Nicolas Cugnot as early as 1769, 
 
Watt, Trevithick, Murdock, Bramah 105 
 
 and William Murdock (1754-1839) is reported to have con- 
 structed a carriage drawn by steam about 1786. Never- 
 theless, Trevithick was the first to build a locomotive in 
 the modern sense, and to use it on the lines of a horse- 
 tramway in Wales. Finally, the introduction of two 
 cylinders, the steam escaping from one being utilized to 
 increase the work by acting on a piston in the second, may 
 be mentioned as being the prototype of the present com- 
 pound engines. This innovation is due to Jonathan Carter 
 Hornblower (1753-1815), who. among other things, invented 
 a machine for sweeping chimneys by a blast of air. Patent 
 difficulties stood in the way of putting the idea of the double 
 cylinder into practice, but it was re-invented and used in 
 machinery set up in Cornish mines in 1804 by Arthur Woolf . 
 
 The name of Murdock recalls that he was the first to 
 make a practical use of coal gas as an illuminating agent. 
 His father was a Scotch millwright ; he entered the employ- 
 ment of Boulton and Watt at the Soho Factory, Birming- 
 ham, in 1777, and a few years later was sent to Cornwall to 
 superintend the fitting of water engines in mines. He esta- 
 blished himself at Redruth, and is credited with several 
 inventions; there is a tradition that he created a sensa- 
 tion among the inhabitants by carrying, to and from the mine, 
 a lantern lit by gas supplied from a bag concealed under his 
 coat. After his return to Birmingham in 1799, he improved 
 his methods for making and storing the gas so much that 
 the exterior of the Soho Factory, and soon after the whole 
 of the interior, was lighted with the new illuminant. 
 
 During the last few years of the eighteenth century, 
 another great step forward in the transmission of power 
 was made when James Bramah (1749-1814) laid the founda- 
 tion of a new branch of engineering by the invention of his 
 hydraulic press. Bramah was the son of a Yorkshire 
 farmer. Being incapacitated for agricultural labour on 
 account of an accident, he started business as a cabinet- 
 maker in London, and made a number of inventions, such 
 as the lock which is known by his name. He suggested 
 improvements in the steam engine, foresaw the possibility of 
 propelling ships by screws, and advocated the hydraulic 
 transmission of power. 
 
106 Britain's Heritage of Science 
 
 CHAPTER IV 
 
 (Physical Science) 
 
 THE HERITAGE OF THE NINETEENTH CENTURY 
 
 IN a superficial review of the history of science a new idea 
 or a striking experiment is associated with an individual 
 name and a particular date. Hence, we receive a general 
 impression that science proceeds by sudden inspirations ; 
 yet, on closer examination, we find that the salient features 
 are connected with each other, and that the great landmarks 
 are generally reached only by a succession of intermediate 
 steps, some of which may be as important as the last which 
 culminates in the final discovery. Time tends to efface the 
 intermediate steps, and so it happens that it is only in dealing 
 with the more recent events that we can obtain a correct 
 view of the continuity of science. To trace this continuity 
 is one of the functions of the historian, but occasionally 
 his efforts will fail, and he will be faced by what appears to 
 be an entirely new departure. Such was Volta's discovery 
 of current electricity, which surprised the scientific world 
 in the first year of the nineteenth century. The electrical 
 shocks which certain fishes can inflict on those who touch them, 
 and an accidental observation by Galvani, an Italian doctor, 
 disclosed a class of phenomena called " animal electricity." 
 But there was much confusion of ideas with regard to the signi- 
 ficance of the observed facts until Volta, the great Italian 
 experimenter, succeeded in separating what was physical 
 from what was physiological in Galvani's results, and so 
 laid the foundation of a new science. By discovering the 
 electrical effects that could be obtained at the contact of 
 two dissimilar metals, Volta was led to those wonderful 
 researches which gave us the electric battery, His previous 
 
Anthony Carlisle, William Nicholson 107 
 
 work had earned for him the Fellowship of the Royal 
 
 Society in 1791, and desirous of showing his appreciation 
 
 of the honour, he not only contributed an important paper 
 
 to the Philosophical Transactions in 1793, but announced 
 
 his latest and greatest discovery in a letter addressed to 
 
 the President of the Royal Society, Sir Joseph Banks. That 
 
 letter bears the date March 20th, 1800, and appears to have 
 
 been sent in two parts, the second of which was delayed 
 
 in delivery, so that it could not be read before the meeting 
 
 of the Society, held on June 26th of the same year. In 
 
 the meantime, the first part of the letter had been privately 
 
 communicated to Sir Anthony Carlisle, the celebrated 
 
 surgeon of Westminster Hospital, and Professor of Anatomy 
 
 to the Royal Academy. Carlisle was mainly interested in 
 
 the physiological effects of electricity, and consulted William 
 
 Nicholson, a man of varied interests, who was employed 
 
 at different times as an official in the East India Company, 
 
 a traveller for the firm of Wedgwood, a school teacher and 
 
 a civil engineer. He had embarked on the publication of 
 
 a scientific periodical Nicholson's Journal and relates in 
 
 its fourth volume the important results he obtained by 
 
 experimenting with the battery constructed according to 
 
 Volta's directions. When two brass wires connected with 
 
 the electric poles were immersed in a tube containing water, 
 
 gas bubbles were seen to rise from one of the wires, while 
 
 the other became corroded. The gas proved to be hydrogen. 
 
 On replacing the brass wires by platinum, it was found that 
 
 oxygen was set free as well as hydrogen ; the electrolytic 
 
 decomposition of water was thus completely effected. This 
 
 was the first step in the brilliant series of experiments by 
 
 which English chemists and physicists traced the connexion 
 
 between chemical and electric action. But we must here 
 
 interrupt our account, and turn for a moment to another 
 
 subject. 
 
 The time had come when the correlation between the 
 various physical manifestations, such as light, heat and 
 power, forced itself into the foreground. The production of 
 heat by mechanical means was effected on a convincing scale 
 by Benjamin Thompson, better known as Count Rumford, 
 who had entered the service of Bavaria for the purpose of 
 
108 Britain's Heritage of Science 
 
 organizing the manufacture of implements of war. His 
 previous experiments had convinced him that in accordance 
 with the views of Robert Hooke and other early physicists, 
 heat consisted in a motion of the ultimate particles of a body, 
 and as he controlled the machinery at Munich for making 
 guns, he had the opportunity of testing the matter. While a 
 cannon was being bored he filled the hollow already formed 
 with water, and found that it became hotter and hotter until 
 it boiled. The conclusion was obvious : heat could actually 
 be generated by mechanical power. 
 
 During an adventurous life Rumford rendered active 
 services to several countries. His family had settled in 
 Massachusetts, where he was born in 1753. At an early 
 age he showed mathematical tastes, but occupied himself 
 with abortive attempts to discover perpetual motion, and 
 with experiments on fireworks. After the outbreak of the 
 American war he entered a local regiment of militia on the 
 American side, where his position was rendered untenable by 
 the doubt which was cast on his loyalty to the caus^ of 
 freedom. He left the army and, when Boston was evacuated 
 in 1776, he came to England, where he was appointed to 
 a clerkship at the Colonial Office, rising rapidly within four 
 years to the position of Under Secretary of State. In the 
 meantime he carried on his scientific pursuits, and was 
 elected a Fellow of the Royai Society in 1779. He returned 
 for a time to Ameiica on active service, but resigned again 
 at the conclusion of the war, with the rank of Colonel. He 
 then determined to join the Austrian army, then engaged in 
 war with Turkey. While on the way to Vienna he was 
 introduced to Prince Maximilian, the future King of Bavaria, 
 and was persuaded to enter the government service of that 
 state. With the consent of King George III., who bestowed 
 the honour of knighthood upon him, he remained at Munich, 
 where he held consecutively the offices of Minister of War, 
 Minister o. Police, and Grand Chamberlain. In addition to 
 the improvements he effected in the Bavarian army, he 
 developed the industries of the country and did much to 
 mitigate he extreme poverty of a large part of the popula- 
 tion. His methods were strongly philanthropic. " To make 
 vicious and abandoned people happy," he said, " it has 
 
Count Rumford, Sir Humphry Davy 109 
 
 generally been supposed necessary first to make them vir- 
 tuous. But why not reverse this order? Why not make 
 them first happy and then virtuous ? " He adopted the 
 name Rumford on being created a Count of the Holy Roman 
 Empire in 1791. Some years later he returned to England 
 and founded the Royal Institution, which received its charter 
 in 1800. His later years were spoilt by an unhappy attach- 
 ment he had formed to the widow of Lavoisier, the great 
 French chemist, who had suffered death on the guillotine 
 during the Revolution. Their marriage took place in 1804, 
 but resulted in an uncomfortable life for several years, until 
 a separation was agreed upon. He died in France in the 
 sixty-second year of his age. 
 
 Rumford probably rendered his greatest service to 
 science when, in 1801, he selected Humphry Davy for 
 appointment as first lecturer on Chemistry and Director of 
 the Laboratory at the Royal Institution. Davy (1778-1828) 
 had already shown his intense enthusiasm for research, 
 though his first attempts at original work were remarkable 
 for great power of scientific imagination, rather than for 
 sobriety of judgment. A trial lecture at which Rumford 
 was present, settled, however, the question of his appoint- 
 ment. 
 
 " I consider it fortunate that I was left much to 
 myself when a child, and put upon no particular plan of 
 study, and that I enjoyed much idleness at Mr. Coryton's 
 school. I, perhaps, owe to these circumstances the little 
 talents that I have and their peculiar application." 
 These words of Davy's, written to his mother at a later 
 date, show that Davy did not establish any reputation 
 for studiousness as a boy ; but his literary gifts must have 
 appeared at an early age, for we are told that the love- 
 sick youths of Penzance employed him to write their 
 valentines and letters. 1 Davy's father had died in poor 
 circumstances, and the mother established a milliner's shop 
 in Penzance to provide the means of educating her younger 
 children. Humphry, the eldest of them, had then already 
 
 1 The account of Davy's life and work is almost entirely derived 
 from Sir Edward Thorpe's most excellent and interesting little volume, 
 " Humphry Davy Poet and Philosopher " (Century Science Series). 
 
110 Britain's Heritage of Science 
 
 spent four years at the Grammar School at Penzance, and 
 one at Truro. At his father's death he realized the necessity 
 of setting to work seriously, and was apprenticed with an 
 apothecary and surgeon practising in Penzance. He then 
 began a course of extensive reading covering nearly all 
 branches of learning. Metaphysics seems to have more 
 especially attracted his attention, and he wrote a number of 
 essays on such subjects as " The Immortality and Imma- 
 teriality of the Soul," " Governments," and " The Credulity 
 of Mortals." Some of his aphorisms indicate great originality 
 of thought, and one almost hears the voice of Poincare in the 
 passage in which he declares that : " Science or knowledge is 
 the association of a number of ideas, with some idea or 
 term capable of recalling them to the mind in a certain 
 order." Turning his attention to experimental research, Davy 
 at this period studied Lavoisier's " Elements of Chemistry," 
 and formed original, but not very happy, ideas on the 
 nature of light, which he communicated to a medical man, 
 Dr. Thomas Beddoes, with important results on his future 
 life. Dr. Beddoes had a notion that the study of the 
 physiological effects of different gases might have important 
 therapeutical applications. With this purpose in view, he 
 founded the " Pneumatic Institution " at Bristol, and, 
 impressed by Humphry Davy's work, he put him in charge 
 of the laboratory. The experiments on gases led to results 
 of importance. While examining the properties of nitrou 
 oxide, Davy observed those remarkable physiological pro- 
 perties which give to this gas its familiar name of " laughing 
 gas." Mary Edgeworth, a sister of Mrs. Beddoes, thus 
 describes the discovery : 
 
 " A young man, a Mr. Davy, at Dr. Beddoes', who 
 has applied himself much to chemistry, has made some 
 discoveries of importance, and enthusiastically expects 
 wonders will be performed by the use of certain gases, 
 which inebriate in the most delightful manner, having 
 the oblivious effects of Lethe, and at the same time 
 giving the rapturous sensations of the Nectar of the 
 Gods ! Pleasure even to madness is the consequence of 
 this draught. But faith, great faith, is, r I believe, 
 necessary to produce any effect upon the drinkers, and 
 
Sir Humphry Davy 111 
 
 I have seen some of the adventurous philosophers who 
 sought in vain for satisfaction in the bag of ' Gaseous 
 Oxyd,' and found nothing but a sick stomach and a 
 giddy head." 
 
 As a result of further experiments with nitrous oxide, 
 Davy mentions its power of destroying physical pain and 
 suggests its application in surgical operations; but no 
 notice of this suggestion was taken for half a century. 
 Davy's researches on gases were preceded by the unhappy 
 publication already referred to " On Heat, Light, and the 
 Combinations of Light, with a new Theory of Respiration," 
 in which he tries to demolish Lavoisier's theory that oxygen 
 was a compound of an elementary substance and " heat." 
 The paper is in great part of a speculative nature, and full 
 of hasty and ill-considered opinions. He was, no doubt, 
 right in his contention that heat is not a substance, but he 
 spoils his case by adhering to the belief in the compound 
 nature of oxygen, replacing only Lavoisier's " heat " by 
 the equally imaginary substance " light." He tries to prove 
 by experiments which are not to the point that light is not 
 due to the vibrationary motion of an elastic medium, and 
 even states that oxygen cannot be produced from oxide of 
 lead by heating it in the dark. A statement of this kind 
 renders it doubtful whether he was sufficiently careful in 
 excluding all possible sources of error in another experiment, 
 described in the same paper, in which two pieces of ice 
 were melted in an exhausted receiver by rubbing them 
 together. 
 
 The errors of a self-trained, impulsive young man would 
 hardly be worth recording were it not for the chastening 
 effect which the severe criticisms they evoked had on his 
 subsequent work. Davy never forgot his lesson; he 
 remained impulsive, but became much more careful in his 
 experiments, and avoided speculative theories like a child 
 avoids fire when it has burnt its fingers. Within a year he 
 published a letter in Nicholson's Journal, in which he says : 
 " I beg to be considered as a sceptic with regard to my 
 particular theory of the combinations of light, and theories 
 of light generally." Before we leave Davy's activities at 
 Bristol, we may quote a passage from one of his letters 
 
112 Britain's Heritage of Science 
 
 which illustrates his wonderful powers of intuition in hitting 
 on the essential points of an experiment : 
 
 " Galvanism " (we should now call it " current 
 electricity ") "I have found, by numerous experiments, 
 to be a process purely chemical, and to depend wholly 
 on the oxidation of metallic surfaces, having different 
 degrees of electric conducting power. 
 
 " Zinc is incapable of decomposing pure water ; and if 
 the zinc plates be kept moist with pure water, the galvanic 
 pile does not act; but zinc is capable of oxidating itself 
 when placed in contact with water holding in solution 
 either oxygen, atmospheric air, or nitrous or muriated 
 acid, etc., and under such circumstances the galvanic 
 phenomena are produced, and their intensity is in pro- 
 portion to the rapidity with which the zinc is oxidated." 
 Davy took up his position as Assistant Lecturer at the 
 Royal Institution in London, and so brilliantly did he 
 discharge his duties that his audience was taken by storm, 
 and the lecture room was soon filled with enthusiastic 
 listeners. The full title of lecturer was given him at 
 once, and the Philosophical Magazine predicted that " from 
 the sparkling intelligence of his eye, his animated manner, 
 and the ' tout ensemble,' we have no doubt of his attaining 
 a distinguished eminence." The control of the subjects to 
 be investigated rested at the time with the governing body, 
 and the Institution having been founded with a view to the 
 practical applications of science, the managers resolved that 
 Davy should give a course of lectures on the Principles of 
 the Art of Tanning; he received leave of absence during 
 three summer months for the purpose of making himself 
 acquainted with the subject. Subsequently he was requested 
 to devote his energies to agriculture, and the various duties 
 which the authorities of the Royal Institution imposed 
 upon him took up much time which would have been better 
 employed in research work. Nevertheless, he found sufficient 
 leisure to return to his favourite study, the chemical action 
 of electric currents, with the result that in 1806 he commu- 
 nicated a paper to the Royal Society which was made the 
 Bakerian lecture of the year. It constitutes a most impor- 
 tant contribution to science, and lays the foundation in 
 
Sir Humphry Davy 
 
 From a painting by Sir Thomas 
 Lawrence, in the possession of the 
 Royal Society 
 
Sir Humphry Davy 113 
 
 some respects more than the foundation of our present 
 science of electro-chemistry. The sensation which the paper 
 created in England was great; its effect abroad may be 
 judged from the fact that the French Academy recommended 
 Davy as first recipient of the gold medal, promised by 
 Napoleon for " the best experiment that should be made 
 in each year on the galvanic fluid." This recognition had a 
 special value, owing to its being bestowed in the face of a 
 bitter political hostility between France and England, then 
 at war with each other. 
 
 Davy continued his researches and in the following year 
 was already able to announce another discovery of funda- 
 mental importance which forms the subject of his second 
 Bakerian lecture. The construction of electric batteries had 
 been materially improved by Cruikshank, a surgeon, and 
 Davy had modelled his own apparatus on Cruikshank's 
 pattern. The metals used were copper and zinc, and two 
 of the batteries consisted of 50 and 100 cells respectively, 
 the plates in the first measuring six, and in the second, 
 four square inches. With the two batteries in series, Davy 
 made a determined attempt to decompose the so-called 
 fixed alkalis : soda and potash. When a current is passed 
 through the aqueous solution of these bodies, only hydrogen 
 and oxygen are set free at the poles. Other experimental 
 methods had, therefore, to be tried. As potash at ordinary 
 temperatures does not conduct the current sufficiently well 
 to show any effect, it was raised to a temperature at which 
 it fused, and the current then produced a highly inflammable 
 substance, which burst into flame by contact with air. In 
 order to isolate that substance, Davy saw that it was 
 necessary to conduct the experiment at ordinary tempera- 
 tures, and succeeded in doing so by utilizing the hygroscopic 
 properties of the substance, which, on exposure to damp 
 air, cause it to become covered with moisture. The current 
 then passed through the highly-concentrated liquid surface 
 layer. With his 150 cells Davy found the electrical effect he 
 looked for, and was able to isolate metallic potassium. He 
 announced his discovery in these words : 
 
 " Under these circumstances a vivid action was soon 
 
 observed to take place. The potash began to fuse at 
 
 H 
 
114 Britain's Heritage of Science 
 
 both its points of electrization. There was a vio ent 
 effervescence at the upper surface; at the lower, or 
 negative surface, there was no liberation of electric 
 fluid; but small globules having a high metallic lustre, 
 and being precisely similar in visible characters to quick- 
 silver, appeared, some of which burnt with explosion 
 and bright flame, as soon as they were formed, and others 
 remained, and were merely tarnished, and finally covered 
 by a white film which formed on then- surfaces." 
 Sodium was similarly obtained from soda. 
 The interest which the announcement of the discovery 
 of two new elements created throughout the scientific world 
 was accentuated by the peculiar properties which distin- 
 guished them from all known metals. They are both lighter 
 than water, and when brought into contact with that liquid 
 burst into flame, owing to their great affinity for oxygen. 
 The investigation of their chemical properties was most 
 difficult, because they oxidize rapidly when exposed to air, 
 and can only be preserved by being immersed in naphtha 
 or some similar liquid. Though a serious illness interrupted 
 Davy's work, he continued to give the Bakerian lecture 
 for six successive years, each time adding something to 
 our knowledge, mainly in connexion with the researches 
 which have already been described. He received the honour 
 of knighthood in 1812, and shortly afterwards informed the 
 managers of the Royal Institution that he could not pledge 
 himself to continue his lectures, but was prepared to retain 
 his position as Professor of Chemistry and Director of the 
 Laboratory without salary. This offer was accepted. In 
 the same year he published his " Elements of Chemical 
 Philosophy," in which he described the " Voltaic Arc," that 
 column of light which is formed between carbon points when 
 a current of sufficient electromotive force is passed between 
 them. Even Davy's vivid imagination could hardly have 
 foreseen the part which this discovery was to play in the 
 future history of illumination. The same paper contains 
 another important result. Partly anticipating the subsequent 
 work of Ohm, the electric resistance of a conductor was 
 shown to be proportional to its length directly, and inversely 
 to its cross -section. 
 
Sir Humphry Davy 115 
 
 His connexion with the Royal Institution was finally 
 severed in 1813, and during the late autumn of that year he 
 set out accompanied by his wife and Faraday on what 
 he called a " journey of scientific enquiry." He was received 
 with great honour in Paris, where he attended the meetings 
 of the Academy of Science, which elected him a corre- 
 sponding member. On November 29th a paper was read 
 to the Academy on a new and remarkable substance dis- 
 covered by Courtois, which, when heated, gave out a violet- 
 coloured vapour. This was followed a week later by a 
 communication from Gay Lussac, pointing out its analogies 
 to chlorine and bromine, and proposing the name " iode " 
 for it. It is characteristic of the impetuous manner in which 
 Davy rushed through a research that, having obtained a 
 small quantity of the substance, he at once set to work, and 
 on December 20 a letter, in which he described his experi- 
 ments, was submitted to the Academy by Cuvier. After a 
 few days he forwarded his complete results to the Royal 
 Society, proposing the name of iodine as the English 
 equivalent for the new substance. 1 
 
 Another example of Davy's activity during this journey 
 remains to be mentioned. At Florence he made use of the 
 great burning-glass belonging to the Accademia del Cimento, 
 by means of which it had already been shown in the reign 
 of Cosimo III. that a diamond is inflammable when the 
 rays of the sun are concentrated upon it. On repeating 
 the experiment Davy found that the products of combustion 
 consisted almost entirely of carbonic acid, and pronounced 
 diamond to be pure carbon. This result had an importance 
 greater than that which attaches to the record of a new 
 experimental fact; for it was the first well-established 
 instance of a chemical element existing in two different 
 now called allotropic forms. 
 
 Shortly after Davy's return to England in 1815, a Society 
 that had been formed to discover, if possible, some method 
 by which explosions of fire-damp could be prevented, asked 
 
 1 The French Academy began to publish its " Comptes Rendus " 
 only in 1835. For a reprint of the papers connected with the dis- 
 covery of iodine, the reader is referred to four communications in the 
 Annales de Chimie," vol. 87, pp. 304-329. 
 
 H 2 
 
116 Britain's Heritage of Science 
 
 his assistance. These explosions claimed many victims, 
 and some remedy had become a pressing need. Davy 
 acceded to the request with enthusiasm, and offered at 
 once to visit some of the mines. The invention of the 
 miner's lamp, which, perhaps, has saved more human lives 
 than any other contrivance, was the result of Davy's efforts. 
 It is not necessary here to describe the principle on which 
 it is constructed, but it may be pointed out that the lamp 
 embodies a technical application of pure science, which no 
 one would have been able to devise without a thorough 
 knowledge of the principles of Physics and Chemistry, 
 together with a considerable experience in laboratory work. 
 The invention was at once appreciated by those whom it 
 was intended to benefit, and one can imagine the pleasure 
 with which Davy received the following letter signed by 
 eighty -three Whitehaven colliers : 
 
 " We, the undersigned, miners at the Whitehaven 
 
 Collieries, belonging to the Earl of Lonsdale, return our 
 
 sincere thanks to Sir Humphry Davy for his invaluable 
 
 discovery of the safe lamps, which are to us life-preservers ; 
 
 and being the only return in our power to make, we 
 
 most humbly offer this, our tribute of gratitude." 
 
 His services were recognized officially by the bestowal 
 
 of a baronetcy. Davy acted as Secretary of the Koyal 
 
 Society between 1807 and 1812; and was elected President 
 
 in 1820. His predecessor, Sir Joseph Banks, had before his 
 
 death expressed his preference for another Fellow, and 
 
 based his objection to Davy on the ground " that he was 
 
 rather too lively to fill the chair of the Royal Society." 
 
 Davy, however, was elected, and filled the chair to the time 
 
 of his death in 1827. 
 
 No account of Sir Humphry Davy's life would be com- 
 plete without reference to his poetic temperament and 
 literary talents. Coleridge said of him : "If Davy had not 
 been the first chemist, he would have been the first poet 
 of his age." By a vivid and impressive style of lecturing, he 
 attracted large audiences to the Royal Institution, which 
 soon became popular. It was a fortunate day for that 
 Institution when Davy was put in charge of the chemical 
 department, for serious financial difficulties were threatening 
 
Sir Humphry Davy 117 
 
 its existence. The stress was at once relieved by the large 
 addition of new members attracted by the engaging per- 
 sonality of the young lecturer. 
 
 A significant light is shed on the small value then 
 attached by the English Universities to experimental science 
 by the fact that none of them ever publicly recognized 
 Davy's work. The only University honour he received was 
 the LL.D. degree from Trinity College, Dublin. 
 
 Yet a great revival of scientific activity had already 
 begun at Cambridge, though at the time of Davy's death 
 it was mainly confined to the domain of pure mathematics. 
 It is sad to think how a spirit of loyalty to its greatest 
 ornament should have paralysed that great University for 
 almost a century, by compelling a rigid adherence to the 
 details of Newton's formal procedure, for it was almost 
 purely a question of nomenclature that delayed progress. 
 In using the method of " fluxions," which is identical in 
 its fundamental ideas with what we now call the Differential 
 Calculus, Newton denoted the rate of change of a quantity, 
 say u, depending on another quantity, say t, simply by 
 placing a dot over the u. If u be the length of path travelled 
 over by a point, and t the time, u would represent the 
 velocity. Leibnitz, starting from the idea of infinitely small 
 quantities, placed a d before the symbol of the variable 
 quantity; dt would be an indefinitely small time, and dujdt 
 would represent the velocity. From the purely philosophic 
 point of view there is much to be said for Newton's notation, 
 but as an instrument of research, that introduced by Leib- 
 nitz had considerable advantages, more especially in the 
 inverse process of integration. When Cambridge began to 
 wake up, Charles Babbage (1792-1871) was among those 
 who helped to introduce the methods which had been so 
 successful in the hands of the great French mathematicians 
 of the eighteenth century. A special society the Analy- 
 tical Society having been formed for the purpose, Babbage 
 neatly expressed the objects of the society as " advocating 
 the principles of pure ' de-ism ' for the ' do-age ' of the 
 University." 
 
 The founder of the new school was Robert Woodhouse 
 (1773-1827), Lucasian Professor of Mathematics between 
 
118 Britain's Heritage of Science 
 
 1820 and 1822, and subsequently Plurnian Professor of 
 Astronomy. Already in his earliest work he strongly advo- 
 cated the continental system of notation, but little progress 
 was made at the time. His views began to prevail mainly 
 through the efforts of Babbage, combined with those of 
 two other Cambridge mathematicians, George Peacock and 
 John Frederick Herschel, the son of Sir William Herschel 
 the great ast onomer. 
 
 Charles Babbage is widely known in connexion with 
 an ambitious calculating machine which he proposed to 
 construct. His first machine was designed mainly for the 
 preparation of astronomical tables; his second was to 
 perform all kinds of arithmetical operations, but it never 
 emerged from the state of general design, and no detailed 
 drawings were made. His mathematical work, however, 
 was not without importance. He was generally active in 
 the cause of science. It was partly through his efforts that 
 the Royal Astronomical Society was founded, and he strongly 
 supported the British Association in its early days. It is 
 notewor hy that at the second of its meetings he strongly 
 urged that "attention should be paid to the object of 
 bringing theoretical science in contact with the practical 
 knowledge on which the wealth of the nations depends." 
 
 Babbage occupied for a time the Lucasian Chair . of 
 Mathematics, but spent the last years of his life in London. 
 
 George Peacock (1791-1858), another important member 
 of the new group, occupied for a time the Lowndean Chair 
 of Astronomy, which he resigned on his appointment to the 
 Deanery of Ely. He played an important part in the founda- 
 tion of the Cambridge Philosophical Society, and in the 
 early history of the British Association. For the latter body 
 he wrote an account of the progress of mathematical analysis, 
 the first of the important series of reports in different 
 branches which are published in its annual volumes. 
 
 Of John Herschel we shall have to speak in another 
 connexion; his name is introduced here because his earlier 
 work deals with mathematical analysis, and helped to 
 introduce the differential notation. 
 
 In their endeavours to reform the teaching of rnathe 
 matics Peacock and Herschel were assisted by William 
 
Babbage, Peacock, Whewell 119 
 
 Whewell (1794-1866), whose name will chiefly be remem- 
 bered by his " History of the Inductive Sciences," a book 
 in three volumes published in 1837, and containing a large 
 quantity of useful information. Whewell ultimately became 
 Master of Trinity College, and gained great influence in the 
 University, but his attitude in later life became strongly 
 conservative and antagonistic to all proposed reforms. 
 
 A new branch of science " Physical Optics " emerged 
 from the work of Fresnel and Young, and when Arago and 
 Brewster had discovered the beautiful colour effects shown 
 by polarized light transmitted through plates cut out of 
 crystals, mathematicians had a good opportunity of applying 
 their talents to test the powers of the wave-theory. When, 
 as in Arago's experiments, the light sent through the plate 
 is confined to a parallel beam, the difficulties are compara- 
 tively slight, and were dealt with satisfactorily by the 
 French physicists. But a number of parallel beams sent 
 through the plate in all directions, and properly iocussed. 
 show more complicated and very beautiful effects, coloured 
 bands being crossed by light or dark brushes of various shapes. 
 The mathematical analysis then becomes more formidable, 
 especially when the crystals have as in the case of quartz 
 the peculiar property of turning the direction of the light 
 vibration. Among those who successfully attacked these 
 problems Airy held a distinguished place. 
 
 George Biddell Airy (1801-1892) had a brilliant Univer- 
 sity career. He entered the University at the age of eighteen, 
 and four years later graduated as Senior Wrangler, and 
 obtained the first Smith's prize. In 1826 he was elected to 
 the Lucasian Professorship, a position which Newton's name 
 has always invested with a certain glamour. 
 
 Though keenly interested in many branches of Physics, 
 Airy was more particularly attracted by astronomical pro- 
 blems, and when a vacancy in the Plumian Professorship 
 occurred in 1828, he became a candidate, and after election 
 took charge of the Cambridge Observatory, which had just 
 been established, mainly through the efforts of George 
 Peacock. The wide range of subjects enriched by Airy's 
 investigations may be illustrated by noting the titles of his 
 first six contributions to science. These were : "On the 
 
120 Britain's Heritage of Science 
 
 figure of the earth " ; "On the use of silvered glass for the 
 mirrors of astronomical telescopes " ; " On the figure assumed 
 by a fluid whose particles are acted on by their mutual 
 attraction and small extraneous forces " ; " On the principles 
 and construction of the achromatic eye-pieces of telescopes, 
 and on the achromatism of microscopes " ; "On a peculiar 
 defect in the eye and a mode of correcting it " ; " On the 
 forms of the teeth of wheels." All these papers mark an 
 advance in their subject matter, and they were written 
 before Airy had reached the age of twenty-four. 
 
 His investigation on eye-pieces was considered to be of 
 sufficient importance for the Royal Society to vote him the 
 Copley Medal, their highest award, in 1831. The paper which 
 he wrote on a " peculiar defect of the eye " deals with 
 astigmatism. Airy, finding that he could not read with one 
 eye, investigated the cause, and observed that the defective 
 eye could not properly focus a point of light which was 
 drawn out into line. This suggested the method of correcting 
 the defect by employing a cylindrical lens. Airy was not 
 aware that Thomas Young had already previously described 
 the astigmatism of the eye. But Young had only met with 
 slight cases, and thought that an ordinary lens slightly 
 inclined was sufficient to correct the defect. 
 
 Airy's principal contribution to Physical Optics is con- 
 tained in a paper in which the coloured curves observed in 
 crystalline plates are mathematically explained and the 
 results more particularly applied to the beautiful spiral forms 
 seen in quartz under certain conditions. Another paper 
 deals with the rainbow, the general explanation of which was 
 first given by Descartes. Most people will have observed that 
 the violet of the rainbow is frequently followed by a dark red 
 and a succession of colours, sometimes twice repeated. The 
 cause of these so-called supernumerary rainbows was given in 
 a general way by Young, who showed that their appearance 
 depends on the interference of light which manifests itself 
 when the sizes of the raindrops are nearly equal ; but Airy 
 gave the first mathematical treatment of the subject. 
 
 Terrestrial Magnetism was another subject to which 
 Airy devoted his attention, more especially after he had 
 gone to Greenwich as Astronomer Royal. The connexion 
 
G. Airy, J. Baden Powell, G. Green 121 
 
 of astronomy with the problems of navigation has always 
 been maintained at the Royal Observatory, and the intro- 
 duction of iron ships presented new problems, because the 
 ship became magnetic under the influence of the earth's 
 forces, and the compass needles were very seriously deflected 
 from the normal direction. An iron ship, The Rainbow, 
 having been placed at his disposal, Airy was able to deter- 
 mine the amount of the deviation experimentally, and 
 following up the observations by a mathematical investi- 
 gation, he showed how the effects could be compensated 
 by placing small permanent magnets near the compass. 
 
 In the work of spreading the new ideas on the nature of 
 light, useful help was given by J. Baden Powell (1796-1860), 
 the son of a gentleman who at one time was High Sheriff 
 of Kent. He graduated at Oxford, took holy orders, and 
 devoted himself to mathematical studies while holding 
 a living in Kent. In 1827 he was appointed Savilian Pro- 
 fessor of Geometry at Oxford, where he took an active part 
 in advocating University reform. Powell wrote a treatise 
 on experimental and mathematical Optics, investigated the 
 reflexion of light from metallic surfaces, and showed that 
 highly absorbing bodies in the crystalline state resembled 
 metals in some of their optical peculiarities. He also estab- 
 lished the commonly used empirical law connecting the 
 refractive 'ndices of rays of light with their wave-length. 
 
 Important as these results may be, they only dealt with 
 isolated problems, but did not touch fundamental principles. 
 The work of George Green (1793-1841) stands on a higher 
 level; indeed, had it become more generally known and 
 appreciated, it might rank as one of the landmarks of 
 science. Green, the son of a miller in Nottinghamshire, 
 entered the University of Cambridge when he was forty 
 years old, and had already written a most important 
 mathematical investigation, which was published by private 
 subscription. This paper dealt with electricity and mag- 
 netism, and it was only during the last few years of his life 
 that he published his investigations bearing on Optics. 
 This part of his work was introduced by a paper on Sound, 
 in which the subject is treated by powerful methods, now 
 familiar to every student of mathematical physics, but 
 
122 Britain's Heritage of Science 
 
 then quite novel ; it marked a considerable step in the 
 philosophical treatment of the subject. As one result of this 
 investigation, the complete internal reflexion which occurs 
 when sound passes from one medium to another, possessing 
 different elastic properties, was demonstrated in opposition to 
 Cauchy, who had come to a contrary conclusion. 
 
 The subject of light is dealt with in a masterly manner 
 in two papers. The general properties of elastic media are, 
 for the first time, examined mathematically, and light is 
 treated as a special case of waves passing through a perfectly 
 elastic body. Green must be considered to be after Newton 
 the founder of the Cambridge school of Mathematical 
 Physics. He did not like Cauchy and Franz Neumann 
 discuss the causes which give bodies then* elastic properties, 
 and could, therefore, dispense with any hypothesis on the 
 mutual action of molecules, or on the ultimate constitution 
 of the luminiferous aether. All he needed was the assumption 
 that its properties were such as to comply with the principle 
 of the conservation of energy. That principle had not, at 
 that time, been formulated, but appears implicitly in Green's 
 work. The investigation solved, under certain suppositions, 
 the problem of the transmission, reflexion and refraction of 
 waves passing through homogeneous elastic bodies. The only 
 question that remained was, whether the observed laws of 
 light could be made to agree with the mathematical formulae 
 obtained. The two main experimental tests that could be 
 applied were the intensities of light reflected at the surface 
 of transparent bodies and the laws of double refraction. 
 The French physicist Fresnel had broken the ground, and 
 obtained satisfactory solutions for both problems, but his 
 analysis was not free from serious defects, and the hypothesis 
 he applied in one case was inconsistent with that introduced 
 in the other. The more rigid treatment of Green, together 
 with the subsequent investigations of Stokes, McCullagh and 
 Rayleigh, led to a deadlock, for no consistent hypothesis 
 could be framed to fit all cases. Fortunately Clerk Maxwell's 
 electrodynamic theory of light disposed of these difficulties. 
 
 Green's first paper on Electricity and Magnetism is 
 considered to be his most important contribution to science, 
 but being of a highly technical character, it must suffice to 
 
George Green, George Stokes 123 
 
 point out that the use of a certain mathematical function 
 already introduced by Laplace was now employed to the 
 greatest advantage under the name " potential," a term which 
 has proved of such universal utility in all branches of physics, 
 owing to its nominal as well as real connexion with the 
 conception of " potential energy." 
 
 Here begins the golden age of mathematics and physics 
 at Cambridge. Its period is coincident with the scientific 
 activity of George Gabriel Stokes (1819-1903), which began 
 in 1842, and extended, with but slightly diminished vigour, 
 to the end of last century. Stokes' position as an investi- 
 gator is among the greatest, but his influence cannot be 
 measured merely by the record of his published work. He 
 united two generations of scientific workers by the love and 
 veneration centred in their gratitude for the assistance and 
 encouragement which, with kindly and genuine interest, he 
 showered upon them out of the wealth of his knowledge and 
 experience. Even those who intellectually were his equals 
 owed much to his sound and impartial judgment. Turning 
 away from the grave which was closing over his lifelong 
 friend, Kelvin was heard to say : " Stokes is gone, and I 
 shall never return to Cambridge." 
 
 Stokes' first papers dealt with fluid motion, a favourite 
 subject, to which he frequently returned. It is impossible 
 in an account intended to be intelligible to the non- 
 mathematical reader, to indicate even the general import 
 of his fundamental investigations in one of the most difficult 
 subjects of applied mathematics. The interest attaching to 
 the shape and propagation of waves will, however, be readily 
 understood, and the importance of questions of stability, 
 which enter so much into the recent advances of aero- 
 nautics, does not need emphasizing at the present time. 
 Both questions rest on that most careful consideration of 
 the fundamental principles of fluid motion, to which Stokes 
 applied his great critical powers. 
 
 The subject of light is, perhaps more than any branch 
 of physics, indebted to Stokes. The problems of the aberra- 
 tion of light and the phenomena of double refraction were 
 the first to attract his attention, and he recurs frequently to 
 the question of the constitution of the luminiferous aether. 
 
124 Britain's Heritage of Science 
 
 He wrote from the point of view of the elastic solid theory 
 of light, which now is abandoned, but his papers, and more 
 especially that on the Dynamical Theory of Diffraction, have 
 lost none of their value. 
 
 Though a keen mathematician, Stokes was equally 
 interested in realities, and he has given us at least one 
 experimental discovery of primary importance. It was known 
 already to the Jesuit Kircher (1601-1680), and to Robert 
 Boyle, that extracts of certain woods presented a different 
 appearance when examined by transmitted or reflected light ; 
 John Herschel and David Brewster added some material 
 facts, and though they tried to theorize on them, they did 
 not make much headway in fitting the facts into the general 
 framework of Optics. Stokes attacked the problem in the 
 true Newtonian manner. Sunlight admitted through a slit 
 in a shutter entered the room, and, after passing through 
 three prisms, was made to form a spectrum on a screen. 
 Solutions of the substances to be examined, such as sulphate 
 of quinine or esculine, were placed in a test tube, and then 
 passed along the screen, so that they were successively 
 illuminated by the different colours of the spectrum. In the 
 red, yellow, green and blue, the substances behaved much 
 like transparent liquids, but when placed in violet they 
 began to shine, emitting a strong blue light, and this was 
 accentuated when the test tube was moved beyond the visible 
 spectrum, into what we now call the ultra-violet. The 
 existence of such rays had already been proved by means of 
 their chemical action, but Stokes widened their range to a 
 quite unexpected degree by using prisms made of quartz, 
 instead of glass; for the glass, as he showed, strongly 
 absorbed those rays. The practical application of these 
 researches, extending optical investigations into the regions 
 of waves which are too short to affect our eyes, became 
 apparent after the introduction of spectrum analysis, and 
 Stokes himself, in a subsequent research, investigated the 
 ultra-violet spectra of metals. But at the time, the novel 
 result emerging from the work was the discovery that the 
 substances experimented upon had the power of changing 
 the wave-length of the light which fell upon them. This was 
 quite contrary to what Newton had taught. Newton was 
 
m 
 
 Sir George Gabriel Stokes 
 
 From a photograph by 
 Fradelle & Young 
 
G. G. Stokes, J. C. Adams 125 
 
 right, of course, with regard to all phenomena known to 
 him, and the proposition that the refrangibility of a ray of 
 light cannot be altered by reflexion or refraction was a 
 great step in advance at the time. As constantly happens, 
 however, new facts require a revision of old dogmas, and 
 though Brewster could never be persuaded, Stokes showed 
 in an absolutely conclusive manner that certain substances 
 could, and did, alter the refrangibility, or, as we now should 
 say, absorbed the incident light and emitted it again with 
 different periods of oscillation. As fluor spar was one of the 
 substances possessing this peculiar property, Stokes called 
 the" whole series of phenomena " fluorescence." 
 
 The later years of Stokes' life centred largely in his 
 activity as Secretary of the Royal Society. The range of 
 his knowledge, the width of his sympathies, and his almost 
 infallible judgment, peculiarly fitted him for a position which 
 offered so many opportunities of advising striving men, and 
 guiding their researches into profitable directions. He died 
 an old man, but his scientific outlook always remained young. 
 New ideas pleased him, even when he could not agree with 
 them, and he delighted in any discovery that did not fit into 
 established theories. 
 
 Two years after Stokes graduated as senior wrangler and 
 first Smith's prize man, the same honours fell to John Crouch 
 Adams (1819-1892). There could be no sharper contrast 
 between two men of similar intellectual attainments than that 
 which marks the scientific life of the two mathematicians. 
 Stokes freely presented his knowledge and experience to 
 others, while to Adams we may apply with greater truth 
 what Maxwell said of Cavendish, that he cared more for 
 doing the work than for communicating it to others. How 
 much of this reserve was due to the events connected with 
 his first research it is impossible to say, but it is difficult 
 to believe that these left him entirely unaffected. For that 
 research was an arduous one, and should have led to the first 
 discovery of the planet Neptune, if the responsible astro- 
 nomers at the time had paid more attention to the calculations 
 of the young Cambridge mathematician. A full account of 
 the history of the new planet, from the pen of Simon 
 Newcomb, is published in the " Encyclopaedia Britannica," 
 
126 Britain's Heritage of Science 
 
 and we may here confine oursel ves to its salient features . When 
 the path of Uranus, the planet discovered by William 
 Herschel in 1781, was carefully examined by Alexis Bouvard 
 of Paris, it was found that it showed irregularities which could 
 not be accounted for by the gravitational action of the other 
 planets known at the time. Bouvard himself entertained 
 the idea that the discrepancies might be due to the attraction 
 of an ultra-Uranian planet, and an English amateur 
 astronomer, the Rev. J. T. Hussey, wrote in 1834 to Airy, 
 who was then Astronomer Royal, offering to make a search 
 for this planet, if some idea of the position could be given 
 him. Adams heard of and became interested in these 
 discussions as an undergraduate, and the following memo- 
 randum, in his own handwriting, dated 3rd July, 1841, is 
 still preserved : " Formed a design, in the beginnuig of this 
 week, of investigating, as soon as possible after taking my 
 degree, the irregularities in the motion of Uranus, which are 
 yet unaccounted for ; in order to find whether they may be 
 attributed to the action of an undiscovered planet beyond 
 it ; and, if possible, thence to determine the elements of its 
 orbit, etc., approximately, which would probably lead to its 
 discovery." 
 
 Having graduated in 1843, he at once set to work on the 
 problem. His first solution was communicated to James 
 Challis, the head of the Cambridge Observatory, in September 
 1845, and about the 1st of November of the same year he sent 
 his calculations to Airy, indicating the position at which the 
 new planet might be looked for. Although, according to the 
 American astronomer Newcomb, two or three evenings 
 devoted to the search could not have failed to make the planet 
 known, Airy was not satisfied, but sent a further enquiry to 
 Adams, which, apparently, was left unanswered. Mean- 
 while. Leverrier, a young French astronomer, had, at the 
 suggestion of Arago, taken up the same subject, and made 
 an independent calculation, which led to a position of the 
 unknown planet agreeing so closely with Adams', that Airy's 
 interest became seriously engaged, and he suggested to 
 Chalhs, on the 9th of July, 1846, to make a search for the 
 planet. Three weeks later Chain's started work in a leisurely 
 way, but was hampered by the want of a good star map. 
 
John Crouch Adams 127 
 
 The delay was decisive, for, on the 18th of September, 
 Leverrier, who had apparently no telescope of sufficient 
 power at his command, wrote to Galle, an assistant at 
 the Berlin Observatory, and the search was commenced 
 on the 23rd. Star charts were at the time being prepared 
 under the auspices of the Berlin Academy of Sciences, and 
 one of them covered the critical region. The same night a 
 star was discovered which was not registered in the map, 
 and the following night its change of position proved that 
 it was the looked for planet. It was afterwards found that 
 Challis, in his sweeps, had observed the planet on the 4th of 
 August, but not having compared his observations with those 
 made subsequently, had failed to recognize it as a moving 
 object. Had he done so, the first discovery of Neptune would 
 have fallen to the credit of Cambridge. The relative merits 
 of Adams and Leverrier were warmly discussed, but history 
 quickly disposes of all such questions of priority. Whether 
 of two discoverers one is a few weeks ahead of, or behind, 
 the other, seems all important at the time, but very soon 
 the adjudgment of merit turns upon the manner in which 
 the work was carried out rather than on the calendar. 
 Nevertheless, when so much seemed to depend on being the 
 first in the field, the disappointment of a young man standing 
 on the threshold of his career must have been severe, and 
 we cannot absolve either Airy or Challis from blame. 
 
 Adams' subsequent work was unostentatious, but always 
 sound and thorough. We may note his investigations on 
 the secular acceleration of the moon's mean motion and on 
 the orbit of the swarm of meteors known as the Leonides. 
 
 After 1844 a series of eminent men passed in rapid 
 succession through the Mathematical Tripos. William 
 Thomson (Lord Kelvin) graduated in 1845, and- P. G. Tait 
 in 1848, but their period of activity is associated with 
 Glasgow and Edinburgh rather than with Cambridge. Edward 
 John Routh (1831-1907) was born at Quebec and took his 
 degree as senior wrangler in 1854. For many years he held 
 a unique position as a teacher in his University, and it may 
 be said that the Mathematical Tripos in its best days owed 
 much of its success to Routh. Such, at any rate, is the 
 testimony of many distinguished men to whose work this 
 
128 Britain's Heritage of Science 
 
 country owes its pre-eminent position in the history of applied 
 mathematics. Routh's " Dynamics of Rigid Bodies " is much 
 more than a text-book, and has become almost a classic ; he 
 has also given us valuable contributions to the investigation 
 of the " stability " of motion. 
 
 Second to Routh in the Tripos list of 1854 stands Clerk 
 Maxwell, one of the men whose work forms one of the 
 great landmarks of science. But, as in the case of Kelvin, 
 much should be said in addition to what has already appeared 
 in the first chapter. The subject of colour vision attracted 
 Clerk Maxwell's attention at an early period, and his experi- 
 ments on the subject helped to establish Young's physio- 
 logical theory which reduced all colour sensations to three 
 primary effects. In dynamics his investigations on Saturn's 
 rings are fundamental. The conclusion arrived at is " that 
 the only system of rings which can exist is one composed 
 of an indefinite number of unconnected particles revolving 
 round the planet with different velocities, according to their 
 respective distances. These particles may be arranged in a 
 series of narrow rings, or they may move through each other 
 irregularly. In the first case the destruction of the system 
 will be very slow, in the second case it will be more rapid, 
 but there may be a tendency towards an arrangement in 
 narrow rings which may retard the process." 
 
 In pure mathematics, Cambridge in modern times gave us 
 Sylvester (1814-1897) and Cayley (1821-1895). Both started 
 life by being called to the Bar, but soon returned to their 
 favourite subject. Sylvester was second wrangler in the 
 Tripos of 1837, but, being a Jew, could not take his degree. 
 After four years' teaching at University College, London, as 
 Professor of Natural Philosophy, he accepted the Chair of 
 Mathematics at the University of Virginia in 1841. He 
 returned to England in 1845, and during the next ten years 
 was connected with a firm of accountants. In 1855 he 
 became Professor of Mathematics at the Royal Military 
 Academy, Woolwich, but on the foundation of the Johns 
 Hopkins University in 1877 he returned to the United States. 
 In 1883 he went to Oxford as successor to Henry Smith. 
 Sylvester's work dealt mainly with higher algebra and the 
 theory of numbers. He possessed great originality; his 
 
J. J. Sylvester, A. Cayley 129 
 
 work is described as " impetuous, unfinished, but none the 
 less vigorous and stimulating." 1 His efforts at poetry 
 may be noted, more especially as he possessed the unique 
 power of expressing Heine's songs in English verse. He was 
 also devoted to music, and at one time took singing lessons 
 from Gounod. 
 
 Cayley's contributions range over a wide field of modern 
 mathematics, and he ranks with the greatest mathematicians. 
 An idea of the nature of his researches may perhaps be given 
 by quoting the verses of Clerk Maxwell, composed to help 
 the promotion of a fund collected for a portrait to be painted 
 by Lowes Dickinson : 
 
 O wretched race of men, to space confined ! 
 
 What honour can ye pay to him, whose mind 
 
 To that which lies beyond hath penetrated? 
 
 The symbols he hath formed shall sound his praise, 
 
 And lead him on through unimagined ways 
 
 To conquests new, in worlds not yet created. 
 
 First, ye Determinants ! in ordered row 
 And massive column ranged, before him go. 
 To form a phalanx for his safe protection. 
 Ye powers of the n th roots of minus one ! 
 Around his head in ceaseless cycles run, 
 As unembodied spirits of direction. 
 
 And you, ye undevelopable scrolls ! 
 
 Above the host wave your emblazoned rolls, 
 
 Ruled for the record of his bright inventions. 
 
 Ye Cubic surfaces ! by threes and nines 
 
 Draw round his camp your seven-and-twenty lines 
 
 The seal of Solomon in three dimensions. 
 
 March on, symbolic host ! with step sublime, 
 Up to the naming bounds of Space and Time ! 
 There pause, until by Dickenson depicted, 
 In two dimensions, we the form may trace 
 Of him whose soul, too large for vulgar space, 
 In " n " dimensions flourished unrestricted. 
 
 In another branch of science William Hallowes Miller 
 (1801-1880) was a worthy colleague of the distinguished men 
 who encouraged the study of science at Cambridge. He 
 
 W, R. R. Ball, " A Short History of Mathematics." 
 
 I 
 
130 Britain's Heritage of Science 
 
 graduated as fifth wrangler in 1826, and was elected to the 
 Professorship of Mineralogy three years later. The mathe- 
 matical knowledge he had acquired fitted him peculiarly to 
 deal successfully with that branch of his subject to which he 
 mainly devoted himself. He developed a new system of 
 crystallography, which rapidly gained acceptance owing to 
 its simplicity and mathematical symmetry. Miller also took 
 a great interest in primary standards, and had a large share 
 in the reconstruction of the standards of length and weight, 
 in 1839, after their destruction in the fire which broke out in 
 the Houses of Parliament. 
 
 We must postpone considering the achievements of a 
 younger generation of Cambridge men, including John 
 Hopkinson, George Darwin, John Poynting and others, 
 until the earlier work of other seats of learning has been 
 dealt with. 
 
 The Scotch Universities claim our first attention. At 
 the beginning of the nineteenth century Thomas Charles 
 Hope (1766-1844) enjoyed an unrivalled reputation as a 
 teacher. It is recorded that in 1823 he lectured to a class of 
 575 students. At the age of twenty-one he was appointed 
 Professor of Chemistry at Glasgow, but resigned soon after 
 to become Assistant Professor of Medicine. In 1795 he 
 settled down at Edinburgh, as joint Professor of Chemistry 
 with Joseph Black, becoming sole Professor of the subject at 
 the latter's death in 1799. Hope discovered the important 
 fact that within a certain range of temperature just above 
 the freezing point, water does not behave like ordinary 
 substances, expanding when the temperature is raised, but 
 contracts, reaching a point of maximum density near 4 C, 
 This is a matter of considerable importance in the economy 
 of nature, for when in the cold of winter the temperature 
 of a sheet of water sinks below the critical point, the colder 
 water is also the lighter. Hence ice first appears as a thin 
 layer on the surface, while the main body can be in stable 
 equilibrium below at a temperature higher than the freezing 
 point. But before the ice can form at all, the whole mass 
 must have cooled down below 4 C. Hope also had an 
 important share in the discovery of the element strontium. 
 A mineral discovered at Strontian in Argyllshire in 1787 
 
W. H. Miller, T. C. Hope, J. Leslie 131 
 
 was at first believed to be a carbonate of barium. Dr. Craw- 
 ford threw doubt on this, and suggested that it contained a 
 new substance, and this was confirmed and definitely proved 
 by Hope. 
 
 John Playfair's successor in the Chair of Mathematics at 
 Edinburgh, and subsequently in that of Natural Philosophy, 
 was John Leslie (1766-1832). After passing through the 
 University as a student of Mathematics and then of Divinity, 
 he spent a year as private tutor in Virginia, and subsequently 
 in the family of Josiah Wedgwood, where he devoted his 
 leisure to Natural Science, translating Buffon's " Natural 
 History of Birds." Returning to his native place, Largo, 
 in Fifeshire, Leslie devoted ten years to scientific research, 
 and then settled down at Edinburgh University. He received 
 the honour of knighthood shortly before his death. Leslie's 
 name is generally connected with his researches on radiation, 
 which would have been more fruitful had he been less 
 dogmatic in upholding what he conceived to be Newton's 
 teaching. He refused to recognize the obvious bearing of 
 Herschel's discovery of radiations less refrangible than red 
 light, and formed artificial and erroneous theories to 
 explain the facts. Nevertheless, his experiments on the 
 radiative power of different substances were conducted with 
 great skill and are of permanent value. The differential 
 thermometer, he employed, maintained for a long time its 
 reputation as a delicate and trustworthy instrument. We 
 owe to him also a valuable method of determining the specific 
 heats of bodies by measuring their rate of cooling. He was 
 the first to freeze water by evaporating it rapidly under the 
 action of an air pump, the vacuum being maintained by 
 sulphuric acid, which rapidly absorbed the aqueous vapour 
 formed. He was also the first to give the correct explanation 
 of the rise of liquids in capillary tubes. 
 
 David Brewster (1781-1868), a man of forceful character 
 and great ability, enjoyed a considerable reputation among 
 his contemporaries, but the weight of his influence was not 
 always placed in the right scale. Like Leslie, he adhered 
 to a verbal interpretation of Newton's doctrine, and in 
 face of the rapidly growing and decisive evidence in favour 
 of the undulatory theory of light, his attitude exceeded all 
 
 I 2 
 
132 Britain's Heritage of Science 
 
 reasonable limits. Even when Fizeau had made his crucial 
 experiment and shown that the velocity of light in ordinary 
 refracting bodies was smaller than in air and not greater, as it 
 should be according to the corpuscular theory, Brewster 
 refused to admit the validity of the evidence. 1 Nevertheless, 
 Brewster was a great experimenter, though an unkind 
 Nemesis turned his most important investigations into an 
 armoury which supplied effective weapons to his opponents. 
 He studied the laws of polarization by reflexion and refraction 
 both for transparent and metallic media; he discovered 
 the connexion between the refractive index and polarizing 
 angle, and the double refraction due to strain. He also first 
 examined crystalline plates under the polariscope in diverging 
 light. He was a prolific writer, and contributed many articles 
 to the early editions of the " Encyclopaedia Britannica." He 
 is said to have given the first impulse to the foundation of 
 the British Association, and was one of its chief supporters 
 during the first years of its existence. 2 
 
 While Brewster was battling in vain against the tenets of 
 modern physics, a young Scotsman, equally distinguished 
 as an experimenter, but superior in judgment and scientific 
 insight rapidly rose to eminence. James David Forbes 
 (1809-1868) was the fourth son of Sir William Forbes, 
 seventh baronet of Pitsligo. He entered the University of 
 Edinburgh at the age of sixteen, and soon afterwards con- 
 tributed anonymously to the Edinburgh Philosophical Journal. 
 At the age of twenty-three, which even then must have been 
 a quite exceptionally early age, he was elected a Fellow 
 of the Royal Society. In 1833 he was appointed Professor 
 of Natural Philosophy at Edinburgh University in succession 
 to Sir John Leslie, Sir David Brewster being the com- 
 peting candidate, and in 1859 he succeeded Brewster in the 
 
 1 The authority for this statement is an oral communication by 
 Stokes. 
 
 2 In the " Encyclopaedia Britannica," eleventh edition, it is stated t 
 "In an article in the ' Quarterly Review,' he threw out a suggestion 
 for * an association of our nobility, clergy, gentry and philosophers * 
 which was taken up by others, and found speedy realisation in the 
 * British Association for the Advancement of Science.' " No such 
 article can be found in the " Quarterly Review." 
 
D. Brewster, J. D. Forbes, P. G. Tait 133 
 
 Principalship of the United College of St. Andrews. His 
 demonstration of the polarization of heat by all the various 
 means by which ordinary light acquires that property, was 
 an experimental achievement of the highest rank, and was a 
 powerful link in the chain which connects the phenomena of 
 radiation. In another series of researches, Forbes appears 
 as one of the pioneers in the important but often neglected 
 field of Geo-physics. He was the first to conduct systematic 
 observations on the temperature of the earth, by inserting 
 thermometers reaching down to different depths beneath 
 the soil, in such a manner that they could be read off without 
 disturbing them. Such experiments allow us to measure the 
 thermal conductivity of the soil, and the loss of heat of the 
 earth through radiation. Later on he determined the thermal 
 conductivity of metals, and discovered that this conduct- 
 ivity diminished as the temperature increased. During a 
 number of visits to Switzerland he investigated the flow of 
 glaciers, and showed that the movement of the ice of glaciers 
 followed the laws of viscous bodies. The tremors of the 
 earth caused by earthquakes also occupied his attention, 
 and he constructed an instrument which was not sufficiently 
 sensitive, but must be considered as the forerunner of the 
 modern seismographs. 
 
 Passing on to more recent times, the name of Peter Guthrie 
 Tait (1831-1900) has already been mentioned as belonging 
 to the Cambridge school of mathematics. The work of his 
 life was devoted to the Edinburgh University, where his 
 teaching of Natural Philosophy exerted a wholesome, though 
 perhaps restraining, influence on the many students who 
 passed through his hands. While he will be remembered 
 chiefly as a vigorous apostle of the doctrine of energy and a 
 forceful propagator of sound dynamical ideas, he made 
 substantial contributions to science, and the " Elements of 
 Natural Philosophy," written jointly by Thomson and Tait, 
 though ^never completed, is a monument " more permanent 
 than bronze." Associated with Tait as a prominent Univer- 
 sity teacher, the name of Crum Brown, Professor of Chemistry 
 between 1869 and 1908, will be remembered by many 
 students who passed through his hands. 
 
 George Chrystal (1851-1911), another Cambridge man 
 
134 Britain's Heritage of Science 
 
 whom death has too soon removed, occupied the Chair of 
 Mathematics at Edinburgh from 1879 to the end of his life. 
 He was a brilliant teacher, possessing one of those clear and 
 critical minds which care more for the quality than the 
 quantity of their work. Everything that flowed from his 
 pen was of the highest standard. He had the distinction 
 of being the first to carry out original investigations in the 
 Cavendish Laboratory at Cambridge, where he tested the 
 truth of Ohm's law to a degree of accuracy far surpassing 
 all previous work. He published a " Treatise on Algebra " 
 and several papers of a mathematical character. During 
 the last years of his life he was occupied with an interesting 
 investigation on the oscillations of level (" seiches ") in the 
 Scotch lakes, initiated by Forel's observations at the Lake of 
 Geneva. 
 
 Glasgow University was naturally dominated during a 
 great part of last century by Lord Kelvin's prodigious 
 activity. His work on heat has already been described; his 
 contributions to the practical applications of science will be 
 referred to later, and as regards his researches on hydro- 
 dynamics and other parts of Mathematical Physics, the 
 reader must be referred to special treatises. 
 
 During a period of forty years, Philip Kelland (1808- 
 1879) taught mathematics at the same University, but his 
 published work deals mainly with the undulatory theory of 
 light, and is concentrated into a few years following his 
 degree course at Cambridge 
 
 The University of Glasgow rendered one of the most 
 important services that have ever been conferred both on 
 science or on industry when, in 1840, it founded, under the 
 auspices of Queen Victoria, the first Professorship of Civil 
 Engineering in the United Kingdom. The second holder of 
 the Chair, W. J. Maquorn Rankine (1820-1872), stands out 
 as a man of striking originality and a great teacher. Most 
 of his early instruction was received at home. Before he 
 entered the University of Edinburgh, at the age of sixteen, 
 he had already studied Newton's " Principia." He then 
 became engaged in various engineering enterprises, until he 
 was appointed Professor of Engineering at Glasgow in 1855. 
 Rankine was one of the imaginative men who are not satisfied 
 
G. Chrystal, W. J. M. Rankine, J. Thomson 135 
 
 with the summary of facts contained in a mathematical 
 formula, but require a definite picture of atoms and molecules, 
 whose dynamical interactions he tried to trace in their details. 
 He invented theories on the causes of elasticity, the constitu- 
 tion of gases, and the motion which constitutes heat. But 
 while most of these theories had to be abandoned, the use 
 which he made of them, and the consequences he drew from 
 them, remained, because they were founded on true dynamical 
 principles, and the results proved in many cases to be inde- 
 pendent of the particular hypothesis from which they happened 
 to be derived. Inspired by Joule and Kelvin, the dynamical 
 theory of heat occupied much of his attention, and he was 
 an early convert to the doctrine of the conservation of 
 energy. We owe to him the introduction of the term 
 " potential energy," one of the happy inspirations which, 
 furnishing an appropriate nomenclature, allowed the funda- 
 mental principle of the conservation of energy to be expressed 
 in a crisp and impressive form. Among his more technical 
 papers, the most important ones deal with stream lines, 
 the efficacy of propellers, and the construction of masonry 
 dams. Rankine was an accomplished musician, and occa- 
 sionally indulged in poetry. Some of the songs composed 
 and set to music by himself were published in a separate 
 volume. 
 
 Rankine 's successor at Glasgow University, James Thom- 
 son, was a man of almost equal distinction. Like his brother, 
 Lord Kelvin, he never went to school. The two brothers 
 passed through the University together, and James took 
 his M.A. degree at the age of seventeen. He was for a time 
 apprenticed to Messrs. Fairbairn at Manchester, but bad 
 health obliged him to return home, where he occupied himself 
 with the invention of appliances for the better utilisation 
 of water power. At various periods of his life he returned 
 to the subject, and we owe to him several forms of water- 
 wheels, a centrifugal pump, and improvements in turbines. 
 At a meeting of the British Association in 1874 he described 
 a pump for drawing up water by the power of a jet, which 
 led to the construction of such pumps on a large scale. Among 
 his purely scientific contributions, that on the lowering of 
 the freezing point of water by pressure is the most important. 
 
136 Britain's Heritage of Science 
 
 From purely theoretical considerations, James Thomson was 
 able to predict that the freezing point of water must be 
 lowered by pressure. His starting point was that water 
 increases in volume on being converted into ice, and the 
 reasoning depends on an application of the second law of 
 thermodynamics. The fact itself was verified soon afterwards 
 by Lord Kelvin, and though the change in the freezing point 
 only amounts to three quarters of a degree Centigrade for 
 100 atmospheres, it yet plays an important part in the 
 behaviour of glaciers, for it explains the plasticity of ice 
 discovered by Forbes. The binding together of snow by 
 the pressure of the hand is also a consequence of the partial 
 melting by pressure, and solidification when the pressure is 
 removed. 
 
 Scotland claims also Sir William Rowan Hamilton (1805- 
 1868) as one of its great men, though his life was spent in 
 Dublin, where his father a solicitor had settled as a 
 young man. The genius of men possessing exceptional 
 mathematical powers frequently shows itself at a very early 
 age, and Hamilton was no exception to this rule. But 
 even before he had an opportunity of discovering his own 
 powers in that direction, he showed a wonderful facility of 
 acquiring foreign languages. At the age of thirteen he 
 is reported to have learned Persian, Arabic, Sanskrit, and 
 Malay, besides the classical and modern European languages. 
 At the age of sixteen he had mastered Newton's " Principia " 
 and the " Differential Calculus," and soon after began a 
 systematic study of Laplace's " Mecanique Celeste." When 
 he was eighteen years old Dr. John Brinkley, the Astronomer 
 Royal for Ireland, is said to have remarked : " This young 
 man, I do not say will be, but is the first mathematician of 
 his age." He entered Trinity College, Dublin, but before he 
 had taken his degree, his career as a student was cut short 
 by his appointment to the Professorship of Astronomy at the 
 Dublin University, and he established himself at the Dunsink 
 Observatory. To all students of Mathematics and Physics, 
 " Hamilton's Principle " is known as one of the fundamental 
 instruments of dynamics, which may be applied to nearly all 
 natural phenomena. 
 
 Hamilton's first investigation on " Systems of Rays " 
 
Sir William Rowan Hamilton 137 
 
 led to an optical discovery that created considerable interest 
 at the time because it drew attention to a curious phenomenon 
 of refraction in biaxal crystals which had not previously 
 been noticed. According to Fresnel's theory, there are in 
 such crystals two directions such that a ray passing along 
 them will emerge as a conical pencil. It follows that, under 
 certain experimental conditions, the two spots of light 
 produced by double refraction are spread out and joined so 
 as to form a ring. Hamilton's prediction was immediately 
 verified by Humphrey Lloyd, and was received as a striking 
 confirmation of Fresnel's theory. 
 
 The later years of Hamilton's lif e were spent in developing 
 the new calculus of " Quaternions," to which he attached 
 great importance; but, though it has yielded methods of 
 great elegance, it has not quite fulfilled its early promise, 
 and has few adherents at the present time. Some of its 
 conceptions, however, permanently survive in the modern 
 vector analysis. 
 
 No single teaching institution has a higher record of 
 scientific output during the last century than Trinity College, 
 Dublin. Humphrey Lloyd, James McCullagh, John Hewitt 
 Jellett, George Salmon, Samuel Haughton, George Francis 
 Fitzgerald, Charles Jasper Joly are names that any University 
 would have reason to be proud of. Lloyd (1800-1881) has 
 already been mentioned in connexion with the verification 
 of conical refraction. In later years he devoted much time 
 to the study of terrestrial magnetism, and took an active 
 part in the magnetic survey of Ireland. James McCullagh 
 was an eminent mathematician whose contributions to the 
 undulatory theory of light take a conspicuous place in the 
 history of that subject. Jellett (1817-1888), like McCullagh, 
 was a mathematician, primarily attracted more by physical 
 and even chemical problems than by pure theory. He is, 
 perhaps, best known for his improvement of the experimental 
 methods for studying the rotation of the plane of polarization, 
 observed in certain bodies like sugar. George Salmon (1819 
 1904), for many years Provost of Trinity College, confined 
 himself to problems of Pure Mathematics, notably in the 
 domain of Geometry. Samuel Haughton (1821-1897) was 
 primarily a geologist, but his versatile mind made frequent 
 
138 Britain's Heritage of Science 
 
 excursions into other subjects, partly suggested to him by 
 his interest in the structure of the earth, but partly discon- 
 nected entirely from his main work, such as his investiga- 
 tions on some problems of sound and light and on the 
 velocity of rifle bullets. He claimed amongst other achieve- 
 ments to have been the originator of the " long drop " in 
 capital punishment. 
 
 Of G. F. Fitzgerald (1851-1901) we cannot speak 
 without lamenting the loss inflicted on science by his early 
 death, He was one of the select few whose genius extends 
 beyond the limits of their own productive work, stimulating 
 the thoughts and penetrating the efforts of their contempo- 
 raries. One of the earliest students of Maxwell's electro- 
 magnetic theory, he realized probably more than anyone 
 else its wonderful future. Of the practical applications of 
 wireless telegraphy he had no thought his interests lay in 
 other directions but he felt that the final proof of the theory 
 must be sought in the experimental confirmation of the 
 transmission of electro-dynamic waves through space, and 
 saw that the difficulty to be overcome was the power 
 necessary to convey the energy from the metallic conductors 
 to the medium. His thoughts even ran ahead of Maxwell's 
 theory, and he escaped the common error of apostles 
 of a new doctrine, who adopt the unavoidable limita- 
 tions of a first presentment as an immovable dogma, 
 mistaking the passing faults of a child for essential features 
 of its character. It was a necessary step in the evolution 
 of the Faraday-Maxwell conception of electrical action that 
 an electric current should be looked upon as the flow of a 
 coherent substance satisfying everywhere the condition of 
 incompressibility. But when the relation between electrical 
 actions and molecular phenomena were considered, the 
 laws of electrolysis suggested that, like matter, electricity 
 might have an atomic constitution. Most of the professed 
 adherents of Maxwell's doctrine would have none of this 
 idea. It seemed to them to violate the dogma of incom- 
 pressibility. But Fitzgerald recognized that there was no 
 real contradiction, and he became one of the great advocates 
 of the electron theory. In this, as in other matters, his 
 mind was receptive and appreciative of the efforts of others, 
 
G. P. Fitzgerald, G. Johnstone Stoney 139 
 
 and his generous disposition made him a willing helper of 
 all who were seeking advice. Though his influence on con- 
 temporary thought was all the greater in consequence, the 
 output of his own work was interfered with. 
 
 Scientific education in Ireland owes much to George 
 Johnstone Stoney (1826-1911), the uncle of Fitzgerald, and 
 for many years, up to the time of its dissolution in 1882, 
 the Secretary of Queen's University. During twenty years 
 he acted in the same capacity to the Royal Dublin Society, 
 an institution founded in 1731 for promoting the arts and 
 industries of Ireland. As an original investigator Stoney 
 was distinguished by a philosophical and balanced mind, 
 but his work was suggestive rather than conclusive. He 
 showed remarkable foresight when he interpreted the true 
 significance of Faraday's laws of electrolysis as indicating 
 the atomic nature of the centres of electric action, and he 
 gave the name of " electron " to the ultimate constituent of 
 electricity. 
 
 When the Queen's Universities were founded in 1845, 
 the appointment of first Vice -President at Belfast fell to 
 Thomas Andrews (1813-1885), a man of remarkable gifts 
 and quite exceptional experimental powers. After a course 
 of study of chemistry at Glasgow University and for a 
 short time under Dumas at Paris, he took the degree of 
 Doctor of Medicine at Edinburgh, and then returned to 
 practise medicine at Belfast. But the call of science was 
 too strong, and he accepted the appointment at Queen's 
 College, which was combined with the Professorship of 
 Chemistry. Andrews' first paper, published in 1836, dealt 
 with a question which has since acquired considerable 
 importance : "On the conducting power of certain flames 
 and of heated air for electricity." He next devoted him- 
 self to the study of the heat developed in chemical com- 
 binations. His work gained in importance as he proceeded, 
 and together with Tait he was the first to demonstrate the 
 true nature of ozone, proving it was only an allotropic form 
 of oxygen. The research for which he is most renowned 
 is that dealing with the liquefaction of gases. When Faraday 
 had succeeded in liquefying carbonic acid, chlorine, and other 
 vapours by pressure, the question naturally arose whether 
 
140 Britain's Heritage of Science 
 
 all gases could be converted into liquids. Pressure alone 
 seemed ineffective with gases like oxygen, nitrogen, and 
 hydrogen, but that might have been due to our inability to 
 apply sufficient power. Andrews, investigating the condi- 
 tions under which carbonic acid could be liquefied, and taking 
 exact measurements of the pressure required at different 
 temperatures, discovered that there was a critical temperature, 
 such that, if the gas be heated above it, no pressure, however 
 great, could convert it into a liquid. Previous experiments 
 by Cagniard de la Tour and others had foreshadowed such 
 a result, and Faraday came very near to the true solution 
 cf the problem, but this does not detract from the value of the 
 classical research by which Andrews finally established his 
 results. We have seen in our own time how, in the hands 
 of Sir James Dewar and of the Dutch physicist, Kammer- 
 lingh Onnes, the subject has developed into a new branch of 
 science, enabling us to investigate the properties of bodies 
 at temperatures so low that molecular motion is almost 
 annihilated. 
 
 The reputation of Oxford University as a centre of 
 research did not, during the last century, rest on its activity 
 in scientific pursuits; but it had among its teachers and 
 pupils at any rate one man whom any seat of learning would 
 have been proud to claim as its own. Henry John Stephen 
 Smith (1826-1889) was both a brilliant mathematician and 
 a great man. He was born in Ireland, but after his father's 
 death his mother removed to the Isle of Wight, and it was 
 there that Henry Smith received his first education. After 
 a short time spent under a private tutor, he went to Rugby, 
 where he became head boy under Dr. Tait. In spite of 
 ill-health, which for some time interrupted his studies, he 
 obtained a Balliol scholarship in 1844, the Ireland scholarship 
 in 1848, and a first-class both hi the classical and mathe- 
 matical schools in 1849. In the meantime he had spent a 
 winter in Paris, where in 1847 he attended the lectures 
 of Arago and Milne Edwards. In 1861 he was elected 
 to the Savilian Professorship of Mathematics as successor 
 to Baden Powell. His researches on the theory of numbers 
 and the elliptic function placed him in the front rank of 
 mathematicians; and he showed the same perfect mastery 
 
Thomas Andrews, Henry Smith 141 
 
 over every subject he touched. The reader is referred to 
 the excellent obituary notice from the pen of Dr. J. W. L. 
 Glaisher for an account of the extent and value of his 
 researches. 1 With regard to his teaching capacity, those 
 who remember him will agree with Dr. Glaisher that : "As 
 an expounder of mathematics before an audience he was 
 unsurpassed for clearness, and his singular charm of manner 
 gave him a remarkable power for fixing the attention of those 
 present." 
 
 His sound judgment was often called upon by others; 
 he was a member of the Royal Commission on Scientific 
 Instruction (1870), and of the Oxford University Commission 
 (1877). During the last sixteen years of his life he acted as 
 Chairman of the Meteorological Council and devoted much 
 time to the work. Quoting again from Glaisher's obituary 
 notice : " It is difficult to give an idea of the position 
 Professor Smith held in Oxford and in society generally, 
 so brilliant were his attainments and so great and varied 
 his personal and social gifts." 
 
 Though Henry Smith was the greatest of the scientific 
 men who taught at Oxford, mention should be made of 
 Odling, the Professor of Chemistry, and Vernon Harcourt, 
 inventor of the pentane lamp as a standard of light. The 
 optical work of Baden Powell has already been referred to, 
 and it will be remembered that Sylvester for a time taught 
 at the same University, succeeding to the Professorship 
 vacated by the death of Henry Smith. The revival of 
 astronomical research at Oxford owes much to the efforts of 
 Charles Pritchard (1808-1893), who, on his appointment to the 
 Savilian Professorship, succeeded in persuading the authori- 
 ties to erect a new observatory, and to provide an adequate 
 equipment. Pritchard, after graduating as fourth wrangler 
 at Cambridge, had spent nearly thirty years as Headmaster 
 of Clapham Grammar School. After his retirement in 1862, 
 he undertook some clerical duties, began to take an active 
 interest in astronomy, and filled the office of Hon. Secretary, 
 and subsequently of President, of the Royal Astronomical 
 Society. When he was appointed to the Chair of Astronomy 
 
 * " Monthly Notices," Roy. Ast. Soc., Vol. XLIV., 1884. 
 
142 Brilahr.s llrri(;i;r <>!' Srinuv 
 
 ;il ()\lord lir \\;IM already M\ly lluvr \(';ir,'; old, l>ul nover- 
 1 liohvs i c IK Ti.'c I ic.dl \ 01 .".uir/.cd I lir uc\\ ( )l.scr\ .1 1 >r\ Trite hard 
 \\an MK N ol lln> oiirly iidvociitr.s ol (lie HMO (>f photography 
 
 III .1,1 i < MM Miiic.M I i c: CM I ell , .'Hid :,lio\\cd IlONN ll could l>c .Mpplird 
 to obtain accurah^ nicM.-.iiicincntM, and ill photoiurt lit' 
 dt^tonuinat IOIIM. 
 
143 
 
 CHAPTER V 
 
 (Physical Science) 
 
 THE HERITAGE OF THE NINETEENTH CENTURY 
 continued 
 
 rilHE foundation of the University of London, followed 
 JL by that of the newer Universities, plays so important 
 a part in the liistory of our subject that a few words must 
 be said on the origin of the movement. It arose not so much 
 out of a feeling that the number of Universities in the country 
 was too small, but in consequence of the religious exclusive- 
 ness of Oxford and Cambridge, which only admitted adhe- 
 rents of the Church of England to University honours. In 
 October 1828, therefore, a number of Nonconformists of 
 various religious denominations combined, and University 
 College was opened as the " University of London," with 
 power to grant degrees. Unfortunately, some influential 
 persons, though favourably inclined to the scheme on educa- 
 tional grounds, objected to its entire dissociation from the 
 national church, and successfully pressed their objections. 
 At the present time the difficulty such as it is would be 
 met by the establishment of a religious Hall of Residence, 
 but no one thought of that expedient, and King's College was 
 founded for the purpose of combining secular teaching with 
 instruction in " the doctrines and duties of Christianity, as 
 the same are inculcated by the Church of England and 
 Ireland." 
 
 The University of London then became a mere examining 
 body, granting degrees, without control of the teaching, while 
 University College received a new charter, without the power 
 of conferring degrees. Among its first Professors was 
 Augustus do Morgan (1806-1871), who was elected to the 
 
144 Britain's Heritage of Science 
 
 post a year after he had graduated at Cambridge as fourth 
 wrangler. De Morgan, the son of a Colonel in the Indian 
 Army, was born at Madras, but brought to England as a 
 child. He combined exceptional mathematical talents, 
 inherited from his mother, with great powers of exposition, 
 and his lectures attracted many men of distinction. Original 
 in his views and his methods, and possessing great strength 
 of character, he followed the dictates of his conscience 
 without regard to consequences. Shortly after his appoint- 
 ment at University College, he sent in his resignation 
 because a colleague, the Professor of Anatomy, had been 
 dismissed without assigned cause. He subsequently con- 
 sented to be re -appointed when the regulations had been 
 altered so as to prevent a repetition of similar incidents. 
 Ultimately he severed his connexion with University College 
 because the governing body took too narrow a view of the 
 religious neutrality of the college, and refused to appoint 
 Dr. Martineau to one of its Chairs on the ground that he 
 was pledged to Unitarianism. But we are here concerned 
 with his scientific productions. His work on the Differential 
 Calculus is one of those rare books which never seem to 
 become antiquated. Its introductory chapter gives us what 
 is probably the best exposition of the fundamental principles 
 of the Calculus that has yet been given. De Morgan's 
 " Budget of Paradoxes," reprinted after his death from 
 articles that had appeared in the Athenceum, contains, 
 besides an historical account of the vagaries of circle-squaring 
 and the trisection of angles, the views of the author on many 
 subjects. Like many mathematicians, De Morgan was 
 devoted to music ; he was a good player on the flute, and had 
 also a talent for drawing caricatures. 
 
 Thomas Graham (1805-1869), the first of the series of 
 great chemists who have adorned the laboratories at Gower 
 Street, commenced his studies at Glasgow, and after com- 
 pleting them under Hope and Leslie at Edinburgh, returned 
 to the former city, where for a short time he held the Chair 
 of Chemistry. When in 1837 he was called to University 
 College, London, as Professor of Chemistry, he had already 
 established his reputation as an original investigator. His 
 chief interest was centred in the study of those physical and 
 
A. de Morgan, T. Graham, W. H. Wollaston 145 
 
 chemical properties which may be expressed in terms of 
 molecular motion. The connexion between the density of 
 gases and the velocity of their diffusion was first investi- 
 gated by him in 1828, but established with greater precision 
 ten years later. The conclusion arrived at, that the velocity 
 of the diffusion is inversely as the square of the density, 
 proves, in the light of subsequent investigation, that the 
 molecules of different gases have at the same temperature 
 the same energy of motion. Graham's investigation 
 covered the whole field, including the inter-diffusion of 
 different gases, their transpiration through capillary tubes, 
 and their effusion into a vacuum, the peculiarities being 
 carefully examined in each case. A further series of papers 
 dealt with molecular motion in liquids, and established 
 the distinction between the inert " colloid " and the more 
 rapidly diffusing " crystalline " substances. These have had 
 important consequences, and we now know that in the col- 
 loidal state we are dealing with molecular aggregates of com- 
 paratively large dimensions, the greater individual masses 
 accounting for the slowness of the movements. Graham's 
 experiments on the passage of liquids through certain 
 membranes opened out a fruitful field of research on the 
 phenomenon called osmosis, which has recently gained 
 great importance. In the domain of pure chemistry, a paper 
 " On water as a constituent of salts " led to results of interest, 
 more especially through the discovery of the polybasic 
 nature of phosphoric acid. 
 
 W. H. Wollaston (1766-1825), a medical man who gave 
 up his practice in order to devote himself to the study of 
 chemistry, had, in the course of his researches on platinum, 
 discovered two new elements, palladium and rhodium. 
 Investigating the peculiar power which palladium has to 
 absorb hydrogen, Graham came to the conclusion that 
 hydrogen, like a metal, could form alloys, and connecting 
 this with the chemical behaviour of this element in other 
 respects, he formed the idea that it was the vapour of a highly 
 volatile metal, to which he gave -the name of " hydrogenium." 
 The expectation then raised was that hydrogen when con- 
 densed into the liquid or solid form would present the 
 characteristic appearance of a metal, but this was not 
 
 K 
 
146 Britain's Heritage of Science 
 
 confirmed when Sir James Dewar actually accomplished the 
 condensation. 
 
 University College during Graham's time had two 
 Professorships of Chemistry, that of " Practical Chemistry " 
 being held by George Fownes (1815-1849), who, on his 
 death four years after the appointment, was succeeded by 
 Alexander M. Williamson (1824-1904). Like Graham, he 
 was of Scotch descent, but his education was cosmopolitan. 
 After attending schools in London, Paris, and Dijon, and 
 studying chemistry during five years in Germany, he stayed 
 three years in Paris and then returned to England. His 
 most important contribution to science is that which eluci- 
 dated the chemical process by which ether is formed when 
 alcohol is brought into contact with hot sulphuric acid. 
 Apart from the intrinsic importance of the subject, the 
 research illuminated a number of problems in chemical 
 dynamics, and led to a better understanding of " catalytic " 
 actions, by which the presence of a body induces chemical 
 transformations without itself being apparently involved in 
 the change. Organic chemistry owes to Williamson many 
 other fruitful ideas. In inorganic chemistry his views on 
 the constitution of salt solutions, though essentially different 
 from our present ideas of " ionization," yet come sufficiently 
 near to them to have prepared the way for the readier 
 acceptance of the theory subsequently developed by Arrhe- 
 nius. They held the field for a time, and made the process 
 of electrolysis more intelligible, 
 
 Williamson played an important part in the scientific 
 life of London ; his was a well-known figure at the meetings 
 of the Chemical Society, and he started the publication, in 
 its Journal, of the monthly reports of all papers of a chemical 
 nature published elsewhere. He acted as Foreign Secretary 
 to the Royal Society during sixteen years, and also assisted 
 the efforts made at various times to convert the University 
 of London into a teaching body. In 1855, when Graham 
 resigned the Chair of Chemistry in University College on 
 becoming Master of the Mint, the two Professorships were 
 united, and Williamson continued to hold the combined 
 Chairs until 1886. 
 
 One of Williamson's colleagues at University College, 
 
A. Williamson, C. Wheatstone 147 
 
 whose brilliant career was cut short by premature death, may 
 here be referred to. William Kingdon Clifford (1845-1878), 
 second wrangler in 1867, held the Chair of Applied Mathe- 
 matics during eight years, but was stricken with tuberculosis, 
 and died in Madeira. He has left many important con- 
 tributions both to applied and pure mathematics. 
 
 Among the Professors at King's College appointed at 
 or shortly after its foundation were two men of world-wide 
 reputation, John Frederick Daniell (1790-1845) and Charles 
 Wheatstone (1802-1875). Daniell constructed the first 
 electric cell which was free from the irregularities caused by 
 polarization, so that constant currents could be obtained. 
 He was mainly interested in meteorology, and rendered 
 valuable services in insisting on accurate and systematic 
 observations of the various phenomena on which the physics 
 of the atmosphere depends. His most successful instrument 
 was that by means of which the humidity of the air is 
 determined from the temperature at which dew begins to 
 deposit. 
 
 Wheatstone began his career as a maker of musical 
 instruments, and during the ten years 1823 to 1833 
 published a number of papers on sound. In 1831 he was 
 appointed to the Chair of Natural Philosophy at King's 
 College, and three years later conducted some experiments 
 which were devised to measure the velocity with which 
 electrical effects are transmitted along a wire, and the 
 duration of an electric spark. In these experiments a rotating 
 mirror was first used to measure small intervals of time. 
 He was also one of the first to recognize the importance of 
 Ohm's law, and to insist on accurate standards and good 
 methods of measuring electromotive force, resistance and 
 current. The Bakerian Lecture for 1843 contains a descrip- 
 tion of the methods employed by him, including the arrange- 
 ment of wires now familiar to every student of science 
 under the name of the " Wheatstone bridge." As he points 
 out himself, the arrangement was first used by Samuel 
 Hunter Christy (1784-1865), Professor of Mathematics at the 
 Military Academy, Woolwich. 
 
 Wheatstone was the first to show how a number of clocks 
 can simultaneously be regulated by the electric current. 
 
 K 2 
 
148 Britain's Heritage of Science 
 
 In Optics he invented the stereoscope and conducted valuable 
 experiments on the physiology of vision. At the British 
 Association in 1871 he exhibited an instrument by means 
 of which the solar time could be determined by utilizing 
 the polarization of the blue light of the sky. This method, 
 as he explained, has several advantages over the ordinary 
 sundial. Wheatstone's spectroscopic observations and his 
 contributions to telegraphy will be referred to in another 
 place (see pp. 154, 188). 
 
 The first sight that meets the eye of a visitor entering 
 the Town Hall of Manchester is the statue of Dalton on 
 his left, and that of Joule on his right. These two great men 
 found a congenial home in the town which numbered amongst 
 its citizens others who, long before it became the seat of a 
 University, upheld the dignity and usefulness of its Literary 
 and Philosophical Society. Such were Thomas Henry (1734- 
 1816), the author of valuable investigations in Chemistry; 
 his son, William Henry (1774r-1836), who studied the laws 
 of absorption of gases by liquids, and William Sturgeon 
 (1783-1850), the inventor of the electro -magnet, who started 
 life as a shoemaker, entered the army as artillerist, became 
 teacher of physics at the military academy of the East India 
 Company, and spent the last twelve years of his life in 
 scientific investigations at Manchester. The ambition of that 
 town to become the seat of a University dates back to the 
 seventeenth century, and though renewed at various times 
 long remained unsatisfied. By the will of John Owens, who 
 died in 1850, a college was founded, which after a period 
 of difficulty rapidly rose to eminence. It numbered among 
 its first professors Edward Frankland (1825-1899), whose 
 researches were fundamental in the development of modern 
 chemistry, and who, next to Davy and Dalton, must pro- 
 bably be considered to be the greatest chemist this country- 
 has ever produced. Having discovered a number of organic 
 substances containing metallic atoms as essential consti- 
 tuents, he investigated the general laws of the formation of 
 chemical compounds, and originated the conception that 
 the atom of an elementary substance can only combine with 
 a certain limited number of atoms of other elements. This 
 led to the discovery of " valency " as the groundwork of 
 
E. Frankland, H. E. Roscoe 149 
 
 chemical structure. Frankland only stayed six years in 
 Manchester; on returning to London, he became lecturer 
 in Chemistry at St. Bartholomew's Hospital, and subse- 
 quently Professor of Chemistry at the Royal Institution 
 and the School of Mines. The latter years of his life were 
 spent in work connected with the examination and purifica- 
 tion of the water supply. He was made a K.C.B. in 1897, 
 two years before his death. 
 
 When Frankland, in 1857, resigned his position at 
 Manchester, the choice of a successor lay between Robert 
 Angus Smith (1817-1884) and Henry Enfield Roscoe (1833- 
 1915). The former was personally known in Manchester, 
 where he resided, and had already done some meritorious 
 work on the impurities found in the air and water of towns, 
 a subject to which he devoted the greater part of his life. 
 Roscoe was only twenty-four years old, but the promise of 
 future success was already foreshadowed in his academic 
 career, and fortunately for Owens College, whose fortunes 
 were then at a low ebb, he was elected to the Professorship. 
 At the age of fifteen, Roscoe had entered University College, 
 London, where he came under the influence of Thomas 
 Graham and Alexander Williamson. After taking his B.A. 
 degree at the University of London, he spent four years at 
 Heidelberg under Bunsen. His activity in Manchester is 
 marked by the foundation of a school of chemistry through 
 which many men of high distinction have passed, and by the 
 happy relations which he established between the industrial 
 community and the academic life which was centred in the 
 college. The prosperity of that institution was soon secured 
 by his strong and genial personality, and when other men 
 eminent both in science and literature had joined its staff, 
 its rise to the dignity of an University became only a question 
 of time. Roscoe was one of the first to point out the need 
 of technical education in this country, but he did not interpret 
 that term in a narrow sense. With him it meant a sound 
 scientific instruction directed towards industrial ends, but 
 not excluding a wider culture. He served on the Royal 
 Commission on Technical Education appointed in 1881, and 
 at the conclusion of its labours received the honour of 
 knighthood. His earnest desire to spread the knowledge and 
 
150 Britain's Heritage of Science 
 
 appreciation of science led him to organize a series of 
 popular penny lectures which attracted large audiences, 
 who had the privilege of listening to such men as Huxley, 
 Huggins, Stanley Jevons, Clifford, and others scarcely less 
 eminent. 
 
 Roscoe's first scientific investigations dealt with the 
 chemical action of light. The subject was suggested by 
 Bunsen, and partly carried out in conjunction with him. 
 Apart from the purely scientific interest attaching to the 
 effect of light in inducing hydrogen and chlorine to com- 
 bine, the research was conducted with the practical object 
 of obtaining a means of measuring the actinic value of day- 
 light under different atmospheric conditions. His principal 
 contribution to pure chemistry consists in his investigation 
 of the element vanadium, which established its true position 
 as a trivalent element of the phosphorus group, and showed 
 that the substance Berzelius had considered to be the metal 
 was really its nitride. 
 
 Among Roscoe's colleagues at Manchester who have 
 helped to establish the reputation of Owens College as an 
 important centre of scientific research, two men stand out 
 prominently: Balfour Stewart (1828-1887) and Osborne 
 Reynolds (1842-1912). It was probably fortunate that a 
 mind of such striking originality as that of Reynolds was 
 never submitted to the discipline of school, though it is 
 difficult to believe that even the severest group-education 
 could have shaped it into a common mould. His father was 
 a clergyman who had passed through the Mathematical 
 Tripos as thirteenth wrangler. The son was brought up at 
 home, and entered the workshop of an engineer at the age 
 of nineteen. He soon found that a knowledge of mathematics 
 was essential to work out the problems that presented them- 
 selves to him, and he decided to go to Cambridge, where he 
 graduated as seventh wrangler in 1867. He then returned 
 to the office of a civil engineer in London, but within a year 
 offered himself as a candidate for the newly-founded Pro- 
 fessorship of Engineering at Owens College. He remained 
 connected with that institution from 1868 to 1905, when 
 he retired owing to failing health. In his methods of 
 instruction Reynolds was a follower of Rankine ; his lectures 
 
Henry E. Eoscoe, Osborne Reynolds 151 
 
 were sometimes difficult to follow, but capable and earnest 
 students always derived great benefit from them, and he 
 brought up a number of distinguished men who look back 
 with gratitude and affection to the inspiration they received 
 from his instruction. 
 
 His researches nearly all possessed fundamental import- 
 ance. To quote Horace Lamb 1 : 
 
 " His work on turbine pumps is now recognized as 
 having laid the foundation of the great modern develop- 
 ment in those appliances, whilst his early investigations 
 on the laws governing the condensation of steam on metal 
 surfaces, and on the communication of heat between a 
 metal surface and a fluid in contact with it, stand in a 
 similar relation to recent improvements in boiler and 
 condenser designs." 
 
 He laid the scientific foundation of the theory of lubrica- 
 tion, and his papers on hydrodynamics have become classical 
 both on account of their theoretical importance and practical 
 applications. Like Rankine, his mind was not satisfied with 
 finding useful applications of his scientific knowledge, but 
 he took an active interest in all questions which touched the 
 foundation of elemental forces and atomic structure. He 
 was the first to give the correct explanation of Crookes' 
 radiometer, and in his later years he tried to formulate a 
 structure of matter and sether which should account for 
 gravitation as well as for electrical and other forces. What- 
 ever may be the ultimate fate of these speculations, they 
 were worked out in a systematic and original manner, and 
 incidentally contain results of permanent value. 
 
 Three years after Roscoe's appointment in Manchester, 
 Robert Bellamy Clifton was elected to the Chair of Natural 
 Philosophy, but resigned in 1865 to take the Chair of Experi- 
 mental Physics at Oxford. His successor, William Jack, 
 subsequently Professor of Mathematics at Glasgow, was 
 interested mainly in the theoretical side of the subject, and * 
 resigned in 1870. It fell to his successor, Balfour Stewart, 
 to organize the department as an effective home of research, 
 
 1 Obituary Notice of Osborne Reynolds, " Proc. Roy. Soc.," 
 Vol. LXXXVIIL, p. xvi (1913). 
 
152 Britain's Heritage of Science 
 
 and to take the first step in that direction by fitting up a 
 laboratory, and encouraging students to submit themselves 
 to a training in accurate scientific measurements. 
 
 Balfour Stewart was brought up for a commercial career, 
 and went out to Australia as a man of business. But his 
 scientific ambitions, inspired as a student at Edinburgh 
 University, soon made him return to that University, where 
 he became assistant to David Forbes. Between 1859 and 
 1870 Stewart acted as Director of the Kew Observatory, 
 and devoted his energies mainly to investigations on 
 Terrestrial Magnetism. Chiefly interested in the connexion 
 between Terrestrial Magnetism and cosmical phenomena 
 such as the periodicity of sunspots, he did not, in the opinion 
 of some influential members of the Gassiot Committee of the 
 Royal Society, which controlled the work of the Observatory, 
 pay sufficient attention to the routine of observations. Some 
 friction resulted, and the vacancy in the Professorship at 
 Manchester gave him the welcome opportunity of changing 
 over to a more congenial position. Unfortunately, a few 
 weeks after he had delivered his first lecture, he met with 
 a serious injury in one of the most terrible railway accidents 
 that have taken place in this country. After an interval of 
 a year, he recovered sufficiently to take up his work again, 
 and though at the age of forty-three his accident had left 
 him with the appearance of an old man, his mind remained 
 he-h and young. During the time in which Balfour Stewart 
 presided over the Physical Department at Manchester, he 
 counted among his pupils several men who subsequently 
 rose to eminence among them John Poynting and Sir 
 Joseph Thomson. His own work at that time was chiefly 
 statistical, dealing with the periodicities of meteorological 
 and cosmical phenomena. 
 
 Balfour Stewart's first and most important work on the 
 radiation of heat is much interwoven with the early history 
 of Spectrum Analysis, and affords the opportunity of giving 
 a brief account of that subject, especially as both in what 
 may be called the period of incubation and in its later 
 developments this country took a most important share. 
 
 As early as 1752, one Thomas Melville, about whose 
 history nothing seems to be known, experimented with 
 
Balfour Stewart 153 
 
 coloured flames, and noted the yellow colour imparted to a 
 flame by soda. His observations were published in a book 
 bearing the title " Physical and Literary Essays." Exactly 
 fifty years later, William Hyde Wollaston, who has already 
 been mentioned as th discoverer of palladium and rhodium, 
 examined the blue light at the base of a candle flame through 
 a prism, and described the bright bands which appear in its 
 spectrum. Young repeated the experiments, and committed 
 what is perhaps the one great error of his scientific work, 
 when he ascribed the colours seen to effects of diffraction. 
 In these and most of the subsequent observations, the light 
 to be examined is passed through a slit, and traversing a 
 prism is separated into its components. The eye focussing 
 on the slit, with or without lenses, sees it illuminated by 
 the various elementary vibrations which the original light 
 may emit. These vibrations show themselves, therefore, as 
 luminous lines, which are images of the slit. The whole 
 appearance is called a spectrum, of which it is customary to 
 speak as consisting of " lines," a misleading term, because it 
 implies that the " line " is a characteristic of the substance, 
 while it is only an incident of the instrument by which the 
 spectrum is examined. The expression, having been univer- 
 sally adopted, may be retained with the understanding that 
 it is the position of the line which indicates the nature of the 
 light vibration, and therefore characterizes the luminous body. 
 Sir John Herschel investigated coloured flames in 1823, and 
 made two significant observations : " The colours thus 
 communicated by the different gases to flame afford, in 
 many cases, a ready and neat way of detecting extremely 
 minute quantities of them," and " no doubt these tints 
 arise from the molecules of the colouring matter reduced to 
 vapour, and held in a state of violent motion." Fox Talbot 
 in 1826 looked at the red lights occasionally used to illuminate 
 the stage in theatres. He correctly ascribed a red line to 
 nitre, but believed the yellow sodium line to be due to sulphur 
 or water. Eight years later Talbot returned to the subject, 
 and clearly pointed out that " optical analysis can distinguish 
 the minutest portions of these substances (lithium and 
 strontium) from each other with as much certainty, if not 
 more, than any other known method." He also offered the 
 
154 Britain's Heritage of Science 
 
 remark that " heat throws the molecules of lime into such 
 a state of such rapid vibration that they become capable of 
 influencing the surrounding setherial medium and producing 
 in it the undulations of light." 
 
 In 1845 William Allen Miller (1817-1870), Professor of 
 Chemistry at King's College, London, published some observa- 
 tions on flame spectra, which were not very accurate, and 
 his plates left it doubtful whether the bright bands or the 
 dark intervals between them ought to be looked upon as 
 the essential feature. This seems to have been one of the 
 stumbling-blocks of early investigators when comparing the 
 continuous spectra of ordinary flames with the discontinuous 
 spectra of incandescent substances. 
 
 An important contribution to the subject was made by 
 William Swan (1818-1894), who, between 1859 and 1880, held 
 the Professorship of Natural Philosophy at St. Andrew's. 
 Swan was the first to introduce (1847) the collimator into 
 spectroscopic observations, and in 1857 he examined and 
 accurately mapped the spectrum of hydrocarbon flames. He 
 discussed the origin of the ubiquitous yellow line and came 
 to the correct conclusion that it is due to the presence of 
 minute quantities of sodium. 
 
 The spectra of the electric sparks passing between poles 
 of different metals were first examined by Sir Charles 
 Wheatstone, and described in a communication to the British 
 Association in 1835. Unfortunately an abstract only was 
 published, but even the short account given ought to have 
 drawn attention to the extreme importance of the matter. 
 The spectrum of mercury was observed and accurately de- 
 scribed, and proved to be identical, whether the spark be taken 
 in air, oxygen gas, the vacuum obtained by an air pump, or 
 the Torricellian vacuum. From these observations the correct 
 inference was drawn that the spectrum is the result of the 
 volatilization and ignition (not combustion) of the ponderable 
 matter contained in the spark. The spectra of zinc, cadmium, 
 bismuth and lead were also obtained by taking the sparks 
 from poles of the melted metals. The paper was published 
 in full in the Chemical News in 1861, and was then found 
 to contain this significant passage : " the number, position, 
 and colour of these lines differ in each of the metals 
 
Spectrum Analysis 155 
 
 employed. These differences are so obvious that any one 
 metal may be instantly distinguished from the others by the 
 appearance of its spark, and we have here a mode of dis- 
 criminating metallic bodies more ready even than chemical 
 examination, and which may be hereafter employed for 
 useful purposes." Wheatstone himself fully realized the im- 
 portance of the subject, as is shown by his remark that " the 
 peculiar effects produced by electrical action on different 
 metals depend, no doubt, on molecular structure, and con- 
 tain hence a new optical means of examining the internal 
 mechanism of matter." 
 
 So much for what was known of the emission spectra of 
 luminous bodies before the date of Kirchhoff and Bunsen's 
 work; let us now turn to the phenomena of absorption. 
 Wollaston was the first who mentioned the dark lines which 
 traverse the spectrum of solar light, but he seems to have 
 looked upon them mainly as lines separating the different 
 colours, though he points out two of them that were not. 
 During the researches which Fraunhofer, the famous 
 optical instrument maker of Munich, conducted with a view 
 to improving the methods of determining the refractive 
 indices of different kinds of glass, sunlight was examined, 
 and found to contain many fine dark lines in its spectrum ; 
 these are now called " Fraunhofer lines." A large number 
 of them were carefully mapped, and the most prominent 
 served him as standards for his measurements; but he 
 examined also the light of a luminous flame and that of 
 some of the stars and planets. The first experiments date 
 back to 1814; nine years later he returned to the subject 
 and measured the wave-lengths of the principal lines by 
 means of his gratings. He pointed out that by using a blow- 
 pipe he could obtain a flame which emits a close doublet 
 of yellow light coincident with the solar lines D. Fraunhofer 
 examined the spectrum of the " electric light," and noticed 
 bright lines; he used the spark of an electric machine as 
 source of illumination and apparently took what we now 
 know to be the spectrum of air as characteristic of the electric 
 source of illumination. Of greater importance are his 
 observations on the spectra of the stars and planets, which 
 allowed him to recognize that the planets, like the moon, 
 
156 Britain's Heritage of Science 
 
 have a spectrum identical with that of the sun, but that 
 some of the stars, like Sirius, show only a few very strong 
 lines. Sir David Brewster in 1834 compared the solar 
 spectrum observed by him with Fraunhofer's drawings, and 
 noticing additional lines which change with the position 
 of the sun, ascribed them correctly to effects produced in 
 our own atmosphere. He had already in 1832 referred with 
 approval to Herschel's suggestion that the dark Fraunhofer 
 lines were produced by absorption in the atmosphere of the 
 celestial bodies. An interesting observation which ought 
 to have attracted attention at the time, but, like many 
 others, was only saved from oblivion when the method of 
 spectrum analysis had been permanently established, was 
 made in France by Foucault. In the spectrum of the voltaic 
 arc, he noticed the presence of what we now know to be the 
 sodium lines, and identified them with Fraunhofer's line D. 
 He found further that on passing the sunlight through the 
 arc, these lines became darker, and further discovered that 
 the lines under certain conditions may be reversed hi the 
 arc itself. 
 
 In all these observations many important facts were 
 recorded, but the ideas on radiation were vague at the time 
 and no effort was made to connect it with absorption. Stokes; 
 in his own mind, seems to have been clear on the matter, and 
 in private conversation with Lord Kelvin " explained the 
 connexion of the dark and bright line (of sodium) by the 
 analogy of a set of piano strings tuned to the same note, 
 which if struck would give out that note, and also would be 
 ready to sound it, to take it up, in fact, if it were sounded 
 in air. This would imply absorption of the aerial vibrations, 
 as otherwise there would be creation of energy." 1 At this 
 stage historically, but in ignorance of much of what has 
 been described, Balfour Stewart undertook a comprehensive 
 investigation of the subject of radiation and absorption. 
 Adopting Preevost's views that equilibrium of temperature 
 means a balance between absorption and radiation, he 
 
 1 The quotation is from a letter addressed by Stokes to Sir J. 
 Lubbock (afterwards Lord Avebury) ; see G. G. Stokes, " Memoir and 
 Correspondence," by Sir J. Larmor, Vol. II., p. 75. 
 
Spectrum Analysis 157 
 
 applied for the first time the ideas of the principle of con- 
 servation of energy to the subject, by considering an enclosure 
 impermeable to heat radiations and at a uniform temperature. 
 This led him to the conclusion that the internal radiation 
 must everywhere be the same and only depend on temperature. 
 The rest follows easily : absorption and radiation must bear 
 a constant relation to each other in such an enclosure. He 
 illustrated the results by many striking experiments. 
 
 Much has been written about the relative merits of 
 several observers who anticipated, in various directions, the 
 great work of Kirchhoff and Bunsen. But the history of 
 science should not aim at assigning marks of merit to 
 different investigators. What interests us is how a great 
 generalization gradually matures, how it begins frequently 
 with the observation of isolated facts, generally overlooked 
 at first because their importance is not recognized. It may 
 be that some link between the disconnected observations is 
 wanting; it may be that experiment has gone ahead of 
 theory or theory may be waiting to be confirmed by ex- 
 periment. When the time is ripe, someone with a better 
 appreciation of the significance of the facts or a deeper 
 insight into their mutual connexion touches the matter 
 with a master hand, and presents it hi a form which carries 
 conviction. Though he may have worked in ignorance of 
 what has been done before, he has worked in an atmosphere 
 in which previous ideas and tendencies of thought have 
 been absorbed, and in general he owes something to the 
 pioneers who have gone before him. In some cases the 
 succession of events which lead to a discovery may be 
 compared to what would happen if a delicate balance carried 
 on one side the arguments in favour of a new idea, and 
 on the other hand the objections which are brought against 
 it. At first the side that bears the objections is much the 
 heaviest; as time goes on the difference becomes less 
 marked, sometimes by the removal of objections, but more 
 frequently by increased evidence in favour of the new idea. 
 Ultimately when sufficient weight is put on that side, a point 
 is reached when the balance tips over. This is the psycho- 
 logical moment when the discovery is accepted, and he 
 who adds the last grain is technically the discoverer. Those 
 
158 Britain's Heritage of Science 
 
 who started loading the scale are then forgotten, unless 
 someone with a taste for historical continuity happens to 
 come across the record of their work. Especially when some 
 national feeling is involved, discussions on priority may then 
 be raised, and continued interminably, because there will 
 always be a conflict between those who attach importance 
 to the intrinsic merit of an investigation and those who 
 look only on the actual influence it has had on scientific 
 thought. In the strict administration of historical justice, 
 oral expressions of opinion like that of Stokes are not 
 admitted as evidence; he himself disclaimed any share in 
 the discovery of spectrum analysis. But as a testimony 
 that the analogy of sound can be applied to the radiations 
 of light and heat, it was a distinct step, and a well ascer- 
 tained and clear pronouncement such as that which passed 
 between Stokes and Kelvin deserves to be placed on record, 
 without detracting from the merit of others. 
 
 In order to appreciate correctly Balfour Stewart's work 
 the following consideration is important. If the foundation 
 of spectrum analysis be made to depend on such laws of 
 radiation as can be derived from the consideration of what 
 happens inside an enclosure of uniform temperature, his 
 priority is well established. He undoubtedly was the first 
 to realize the significance of studying the equilibrium of 
 heat inside such enclosures, and led the way in a direction 
 of research which has proved to be of capital importance 
 in the theory of radiation. But as regards their practical 
 bearing on spectrum analysis, too much weight has been 
 given to theoretical considerations founded on thermal 
 equilibrium. In all spectroscopic observations, the loss or 
 gain of heat is the essential factor. The step which takes 
 us from the uniform enclosure to the radiation and absorp- 
 tion when there is no equilibrium is not so simple as has 
 generally been assumed, and it is safer to accept spectrum 
 analysis as being mainly founded on experiment together 
 with such plausible theoretical analogies between sound and 
 light as were pointed out by Stokes. In this respect, the 
 work of Herschel, Talbot, Wheatstone, and Swan is of 
 greater importance in the history of spectrum analysis than 
 the theoretical work of Balfour Stewart, who, however, also 
 
Spectrum Analysis 159 
 
 illustrated his views by striking experiments on the relation 
 between radiation and absorption. Incidentally, he corrected 
 a wrong idea based on erroneous experiments by a Dr. Bache 
 in the United States, who claimed to have shown that, while 
 the surface colour greatly affected the absorption, it had no 
 effect on the radiation of a body. 
 
 Bearing in mind what has been said, it is not surprising 
 that, notwithstanding all that had been done before their time, 
 Kirchhoff's and Bunsen's work created a deep impression. 
 The combination of a physicist and chemist was almost 
 necessary to bring out the full significance of the observations ; 
 and the accumulated experimental evidence furnished by 
 them was complete in itself, and left no doubt as to the 
 value of the new method of investigation, which formed not 
 only a most delicate test of the chemical nature of substances 
 which we handle in the laboratory, but would also be applied 
 to the analysis of any light-emitting body however great 
 its distance might be. It is well known how the spectroscope 
 at once revealed a number of new metals, among them being 
 thallium, which was first identified by Sir William Crookes. 
 
 The further development of the subject disclosed a far 
 greater potentiality of the spectroscopic attack than was 
 dreamed of by its originators. At first it was considered 
 that the spectrum was an atomic property ; in other words, 
 that each atom preserved its spectrum when combined 
 with other elements, so long at any rate as the substance 
 remained in the gaseous state. There was not much oppo- 
 sition to the next step, by which compounds were shown 
 to have independent spectra, but when it appeared that 
 even one and the same element could give a number of 
 different spectra under different conditions, fresh fields of 
 investigation were opened out. In the further elucidation 
 of the subject, this country has helped as much as, and 
 perhaps more than, any other. It will be sufficient to mention 
 the work of Lockyer, Liveing and Dewar, and the investi- 
 gations of Lord Rayleigh on the Optics of the Spectroscope, 
 which, by pointing out the limits of their power for given 
 optical appliances, have shown the direction in which an 
 extension of these limits is possible. In the investigation of 
 the absorption spectra of organic compounds a prominent 
 
160 Britain's Heritage of Science 
 
 place must be given to Sir William Abney and Walter Noel 
 Hartley (1846-1913). 
 
 The success of Manchester in establishing great research 
 schools encouraged other cities to introduce university 
 teaching into great manufacturing centres. But Man- 
 chester had a start of over twenty years, and its record is 
 necessarily greater for that reason alone. Nevertheless, some 
 of the younger universities soon attracted men of eminence, 
 and of these, two stand out prominently, Arthur Riicker 
 (1848-1915) and John Poynting (1852-1914), the first Pro- 
 fessors of Physics at Leeds and Birmingham respectively. 
 
 Although Riicker was only connected with Leeds Univer- 
 sity during eleven years, much of his scientific work origi- 
 nated during that time ; and notably his researches on thin 
 films, carried on jointly with Professor Reinold. From the 
 colours of soap bubbles or of similar films their thickness 
 may be calculated, but as they thin out, the colour effects 
 disappear, and the film is black by reflected light. This 
 means that its thickness is less than the wave-length of 
 light and can not be measured by the simple optical method. 
 In order to investigate the molecular phenomena which 
 ultimately lead to the breaking of the film, Reinold and 
 Riicker undertook the extremely difficult task of measuring 
 the thicknesses of films when they are too thin for the 
 colour test to be applied. Their first method consisted in 
 determining the electric resistance of the films, the second 
 in increasing the number of films, until their aggregate 
 thickness became as great as the wave-length of light. 
 Both methods led to the same results, and some delicate 
 points in the subject of Molecular Physics were cleared up 
 by the investigation. 
 
 It is not possible here to enter more fully into other 
 important researches of Riicker, which included the two great 
 magnetic surveys of the United Kingdom, carried out in 
 association with his friend, Sir Edward Thorpe. Riicker 
 was an organizer and administrator of the highest ability, 
 and left the mark of his activity on all the institutions with 
 which he was connected. In 1886 he was appointed Pro- 
 fessor of Physics at the Normal College of Science in London, 
 and in 1896 elected Secretary of the Royal Society; both 
 
James Prescott Joule 
 
Arthur Riicker, John Poynting 161 
 
 positions he gave up when he accepted the Principalship 
 of London University in 1901. 
 
 John Poynting was the first Professor of Physics at 
 Mason College (now the University), Birmingham. He was 
 brought up in Manchester, and obtained his first instruction 
 in Physics from Balfour Stewart. In due course he went 
 to Cambridge, graduated as third wrangler, and was elected 
 to a Fellowship at Trinity College in 1878. For a time he 
 worked in the Cavendish Laboratory, and in 1880 went to 
 Birmingham, where he remained until his death. Poynting 
 belonged to the rare type of men who are more critical of their 
 own work than of that produced by others. The number 
 of his papers is therefore comparatively small, but each 
 of them marks some definite and generally important step. 
 He broke new ground when he investigated the path along 
 which energy may be considered to be propagated in an 
 electromagnetic field, and the vector, by means of which he 
 represented the magnitude and direction of the transmitted 
 energy, has proved to be a fruitful conception. His in- 
 vestigations on the " pressure of light " have also led to 
 many interesting consequences, which are likely to gain 
 considerable importance in questions connected with the 
 constitution of the sun and stars. In another series of 
 experiments he attacked the difficult problem of gravitational 
 attraction and showed how an apparently unpromising 
 method may be skilfully applied so as to give valuable 
 results. 
 
 Turning to the share of non-academic workers in the 
 recent progress of science, it is not surprising that it tends to 
 become less prominent, various reasons combining to render 
 it more and more difficult for the so-called amateurs to hold 
 their own. It is now generally only in those subjects which, 
 in consequence of great specialization, have become almost 
 entirely self-contained, that a man who is unable to devote 
 his whole time to study can hope to produce original work 
 of high quality. The most effectual of the contributing 
 causes has, however, probably been the growth of the 
 universities and their emancipation from the narrow ideas 
 of the Middle Ages. There is a university within the reach 
 of nearly everyone and men are drawn into the academic 
 
 L 
 
162 Britain's Heritage of Science 
 
 profession who previously would have had to pursue their 
 science in solitude. But when all is said, much valuable 
 work is still being done, and was to an even greater extent 
 being done last century, by men who can only spare their 
 leisure to the pursuit of science. The work of the most 
 prominent of them may be briefly summarized. 
 
 Francis Baily (1774-1844), the third son of a banker. at 
 Newbury, may serve as an example of a man who, without 
 exceptional abilities, exerted a great and beneficial influence 
 on the science of his time by perseverance, organizing power, 
 and an unselfish devotion to its interests. After a long and 
 adventurous journey to America, on which he spent three 
 years of his early life, he engaged in commercial pursuits. 
 While he was earning a considerable fortune, he found time 
 to write an important work on the " Doctrine of Interest 
 and Annuities analytically investigated and expounded," and 
 a similar book on the " Doctrine of Life Annuities and 
 Assurances." Through an acquaintance with the chemist 
 Priestley, he had developed a taste for experimental enquiry, 
 and later he became interested in astronomy, to which 
 subject he devoted himself entirely after his retirement from 
 business in 1825. He was one of the founders of the Royal 
 Astronomical Society, and acted as its secretary during the 
 first three years of its existence. He did not himself observe, 
 but his critical and historical work proved to be of great 
 value. The publication of serviceable star catalogues, first 
 for the Astronomical Society and then for the British 
 Association, is mainly due to his zeal. His experimental 
 work included the investigation of the effects of air resistance 
 on the time of swing of a pendulum, and a repetition of the 
 Michell-Cavendish experiment on gravitational attraction. 
 
 John Peter Gassiot (1797-1877), originally a wine 
 merchant, was the first who systematically studied the 
 luminosity observed when an electric discharge passes 
 through gases at low pressure. The glass tubes with metal 
 electrodes which he had constructed for the purpose soon 
 came into common use under the name of Geissler tubes. 
 Gassiot was not only a successful experimenter, but also 
 a benefactor who used his wealth in encouraging and pro- 
 moting science. His gift of 10,000 to the Royal Society, 
 
Baily, Gassiot, Grove, Schunck 163 
 
 to be devoted to the carrying out of magnetical and 
 meteorological observations with self-recording instruments, 
 has proved to be of special value. 
 
 Lord Justice Grove (18111896), while actively engaged 
 in practice at the Bar, found time to invent the electric 
 battery which goes by his name, and was, before the days 
 of electrodynamos, the most convenient appliance for the 
 production of large currents. Many of his electrical and 
 chemical experiments were of value, and his book on the 
 correlation of physical forces gives proof of a wide outlook 
 in science. 
 
 William Spottiswoode (1825-1883), the head of the 
 well-known printing firm, was at the same time an eminent 
 mathematician, and his scientific attainments were sufficiently 
 distinguished to justify his election to the Presidency of the 
 Royal Society, an office which he held at the time of his 
 death. 
 
 Edward Schunck was the typical man of independent 
 means who unselfishly devotes his whole time and wealth 
 to the pursuit of knowledge. He was born in Manchester 
 in 1820, his father having founded an important business 
 in that city. He studied chemistry in Germany, and shortly 
 after his return to England, settled down to research work 
 mainly connected with the colouring matter derived from 
 plants. Alizarin, the colouring substance of madder, 
 attracted his first attention, and his investigations prepared 
 the way for its subsequent artificial production. 
 
 He also made important additions to our knowledge 
 of the chemical composition of indigo and chlorophyll. 
 His laboratory, containing a finely ornamented room used 
 as a library, was beautifully fitted out for purposes of 
 research. Its contents were left to Owens College by his 
 will, and ultimately the laboratory was taken down and 
 re-erected as an annexe to the Chemical Laboratories of the 
 Manchester University, where it is now entirely devoted 
 to research work. 
 
 Henry Clifton Sorby (1826-1909) was another of the 
 busy men of so-called leisure who devote their lives to the 
 pursuit of science. His instrument was the microscope, and 
 he began investigating the minute structures of minerals 
 
 L 2 
 
164 Britain's Heritage of Science 
 
 with a view to elucidating problems of geology. By studying 
 sections of rocks he laid the foundation of modern petro- 
 graphy and, devising methods for the examination of metal 
 surfaces, he originated a new era in the science of metal- 
 lurgy. He became interested in metals because he wanted 
 to examine the structure of meteorites. Not being able to 
 cut sections sufficiently thin to be transparent, he applied 
 acid to the polished surfaces, which then showed patterns 
 indicating the manner in which the crystallized parts of 
 the body hang together. The same method applied to ordi- 
 nary metals, and more especially to steel, has led to results 
 of far-reaching importance in practical engineering. 
 
 It is difficult to assign a correct position in the history 
 of science to a man whose work is entirely neglected and 
 buried, to be brought to light only when its novelty has 
 disappeared. Such a man has had no influence in shaping 
 scientific thought, yet his merits are as great as if his 
 discoveries had been acknowledged at the time. John 
 Waterston (1811-1884) probably furnishes the most con- 
 spicuous example of a long-continued neglect of work 
 which would have marked a great advance in knowledge, 
 had it been recognized at the time of its maturity. A paper 
 which contains results of the highest value in the theory 
 of gases was presented to the Royal Society, but only a 
 short and insufficient abstract was printed. In the words 
 of Lord Rayleigh : " the omission to publish it at the time 
 was a misfortune which probably retarded the development 
 of the subject by fifteen years." In the complete investi- 
 gation discovered in the archives of the Royal Society by 
 Lord Rayleigh and published in the Philosophical Trans- 
 actions fifty years after it had been communicated, it is 
 shown how the kinetic theory can explain in a simple 
 manner the physical behaviour of perfect gases. It is proved 
 that the kinetic energy of a molecule is a measure of its 
 temperature, whatever the nature of the gas, and it contains 
 the discovery though imperfectly demonstrated that " in 
 mixed media the mean square molecular velocity is inversely 
 proportional to the specific weight of the molecules." The 
 ratio of the specific heats of constant pressure and volume 
 is calculated for molecules exhibiting internal motions, only 
 
H. C. Sorby, J. Waterston, G. Airy 165 
 
 a slip of calculation preventing the correct result being 
 obtained. 
 
 Of Waterston's life very little is known. He was born 
 in Edinburgh in 1811, and showed great aptitude for mathe- 
 matics while at the High School of that town. He then 
 became Naval Instructor in the service of the East India 
 Company. After his retirement he lived in various towns 
 of Scotland, and finally at Edinburgh. One evening in the 
 spring of 1884, he left his lodgings for his evening walk, and 
 was never seen again. It is supposed that he went to Leith 
 to look at a new breakwater which was being constructed 
 there, and that he accidentally fell into the water and was 
 swept away by the tide ; but this rests on surmise only. 
 
 Among professional British astronomers during the last 
 century four men stand out prominently : Sir George Airy, 
 Sir John Herschel, John Crouch Adams, and Sir David Gill. 
 When Airy was called to take charge, first of the Observatory 
 of Cambridge and later of the Royal Observatory at Greenwich, 
 he had already made his name famous by his mathematical 
 and optical investigations, which have been mentioned in 
 connexion with his career at Cambridge. In astronomy he 
 proved himself to be equally eminent as an administrator and 
 investigator. He introduced revolutionary reforms in the 
 practice of observatories by insisting on a rapid reduction 
 and publication of all observations. After his appointment as 
 Astronomer Royal, he set to work at once to reduce the series 
 of observations of planets which had accumulated during 
 eighty years without any use having been made of them. 
 This was followed up by a similar reduction of 8,000 lunar 
 observations. He was equally energetic in adding to the 
 instrumental equipment. When Greenwich was first founded, 
 the longitude determination at sea depended to a great extent 
 on measuring the distance between stars and the moon. Hence 
 accurate tables of the position of the moon were essential, and 
 the preparation of these tables has always been considered 
 to be the chief care of Greenwich. The observations were made 
 with a transit telescope which could only be used when the 
 moon was passing the meridian, until Airy in 1843 persuaded 
 the Board of Visitors to take steps for constructing a new 
 instrument which would enable him to observe the moon 
 
166 Britain's Heritage of Science 
 
 in any position. In 1847 this instrument was at work, and 
 other important additions to the equipment were made as 
 occasion arose. Airy also originated the automatic system 
 by which the Greenwich time signals are transmitted each 
 day throughout the country. Among his theoretical investi- 
 gations in pure astronomy, one of the most important resulted 
 in the discovery of a new inequality in the motions of Venus 
 and the earth due to their mutual attraction, and this led to 
 an improvement in the solar tables. 
 
 Sir John Herschel (1792-1871) was the only son of the 
 great astronomer whose work was considered in a previous 
 chapter. After graduating as senior wrangler in 1813, he 
 joined a number of friends in their efforts to reform the 
 teaching of mathematics at Cambridge. The astronomical 
 problems which had occupied the later years of Sir William's 
 life then attracted the son, who, after his father's death, 
 completed the work on double stars, and published an 
 important memoir on their orbits. 
 
 In 1833 he embarked for the Cape, in order to extend to 
 the southern hemisphere the general survey of the heavens 
 which his father had carried out in the northern sky. It 
 was to a great extent a spirit of loyalty to his father which 
 kept him to the subject of astronomy, for his own bent of 
 mind drew him more towards physics and chemistry. He 
 discovered the solvent power of hyposulphite of soda on 
 otherwise insoluble salts of silver, a property which later 
 proved so useful in photography. As a writer he was clear 
 and effective. His article on " Light " in the Encyclopaedia 
 Metropolitana forms an excellent record of what was known 
 at the time, and his " Outlines of Astronomy " may still 
 serve as a useful book of reference. 
 
 The work of Adams has already been described in a 
 previous chapter (p. 125). 
 
 David Gill (1843-1914), after a period of study at the 
 University of Aberdeen, entered his father's business, 
 which consisted in the making of clocks. But his interest 
 in science, stimulated by the influence of Clerk Maxwell, 
 who for a time held a Professorship at Marischall College, 
 soon asserted itself, and he established a physical and chemical 
 laboratory in his father's house Turning his attention to 
 
Sir John Herschel, Sir David Gill 167 
 
 astronomy, he became acquainted with, and ultimately 
 engaged as private assistant by, Lord Lindsay, an enthusiastic 
 amateur astronomer, then about to erect a private observatory 
 at Dunecht. He accompanied Lord Lindsay in his expedition 
 to Mauritius, undertaken for the purpose of observing the 
 transit of Venus in 1874. This rare event, as previously 
 explained in connexion with its first observation by J. 
 Horrocks, serves to determine the distance between the 
 earth and the sun, but alternative methods promising more 
 accurate results had already been suggested. The relative 
 distances of the different planets from the sun being known 
 by their times of revolution, we may substitute the measure- 
 ment of the distance of any one planet which is in a suitable 
 position for the direct determination of the solar distance. 
 Certain planets occasionally approach the earth sufficiently 
 near to apply this method. As the earth turns round its 
 axis, the observer's point of view is sufficiently altered 
 between a morning and evening observation to show a 
 measurable shift in the position of a planet as compared 
 with that of the surrounding stars. While at Mauritius 
 Gill found that one of the minor planets, Juno, happened 
 to be suitably placed to test the method, and he obtained 
 most encouraging results. A good opportunity of pursuing 
 the investigation presented itself in 1877, when the situ- 
 ation of the planet Mars was exceptionally favourable for 
 the purpose. Gill left the service of Lord Lindsay and 
 established himself on the island of Ascension. Though the 
 results obtained were good, Gill confirmed his conclusion 
 that the minor planets were better suited for accurate 
 measurements. He returned to the subject ten years later, 
 and a combination of observations of three minor planets, 
 made partly by Gill at the Cape and partly by other astronomers 
 whom he had interested in the work, has given us the best 
 determination of the solar parallax we possess. 
 
 In 1879 Gill was appointed Astronomer Royal at the 
 Cape, and he directed the work of the observatory with 
 distinguished success until 1906. Unbounded perseverance, 
 unrivalled skill in observing, and an exceptional mechanical 
 knowledge which served him in the design of instruments 
 were combined in his person to a rare degree. A favourite 
 
168 Britain's Heritage of Science 
 
 instrument of his, the potentialities of which for accurate 
 measurements he was the first to recognize, was the helio- 
 meter, the essential par of which consists of an object-glass 
 divided into two halves, which could be made to slide along 
 the dividing line. If the image of a star formed by one half 
 be brought into coincidence with the image of a neigh- 
 bouring star formed by the other half, the angular distance 
 between the stars is indicated by a suitable measuring 
 arrangement. With a telescope of this construction Gill 
 instituted a series of observations for the determination of 
 stellar parallaxes, which raised the subject up to a higher 
 plane. Another important research carried out by Gill with 
 the assistance of others was the determination of the mass of 
 Jupiter by observations of his satellites. 
 
 Gill was not only an eminent investigator; large ideas 
 originated in his mind, and were pushed forward with 
 unlimited energy. He originated the great international 
 enterprise for cataloguing and charting the whole sky by 
 photography. He also successfully advocated an accurate 
 trigonometrical survey of the whole of South Africa, and 
 formed a scheme for the measurement of an arc of meridian 
 which should run along the thirtieth meridian east of Green- 
 wich through the whole length of Africa to the mouth of the 
 Nile, and connect by triangulation through the Levant with 
 the Roumanian and Russian arcs. He secured the assistance 
 of Mr. Cecil Rhodes, and the work, though frequently inter- 
 rupted, partly through the political troubles in Africa and 
 partly through want of money, was proceeding slowly when 
 stopped by the outbreak of the present war. 
 
 Gill's scientific activity was continued after his return to 
 England, and during the last years of his life he endeavoured 
 to stimulate the manufacture of optical glass in this country. 
 His efforts deserved a better response than they received 
 and though they were primarily directed towards securing 
 the large blocks required for telescopes, the whole question 
 of glass manufacture, which has since become of such pressing 
 importance, was involved. By his death British science lost 
 an intensive driving force. 
 
 While professional astronomers carried on their excellent 
 researches the great improvements in the construction of 
 
D. Gill, Lord Hosse, W. de la Rue 169 
 
 reflecting telescopes during the nineteenth century was 
 entirely the work of amateurs. William Parsons, third Earl 
 of Rosse (1800-1867), took the first step in 1827. As William 
 Herschel had never published his methods, there was no 
 established procedure to shape concave mirrors. Lord Rosse 
 had to start from the beginning, and to invent the machine 
 for grinding and polishing the speculum metal to the required 
 shape. After a number of attempts he was eminently 
 successful, and in 1845 completed a mirror six feet hi dia- 
 meter with a focal length of nearly sixty feet. The structure 
 necessary to hold and move such a gigantic telescope pre- 
 sented considerable engineering difficulties, but these were 
 overcome, with the result that Lord Rosse was soon able 
 to announce a number of important discoveries. Many 
 luminosities that had been classed as nebulae were found to 
 consist of closely packed star clusters. Others remained 
 unresolved, and among them the interesting family of spiral 
 nebulae was recorded. Further improvements in the methods 
 of shaping and polishing mirrors are due to William Lassell 
 (1799-1880) and James Nasmyth (1808-1890). The former, 
 a Lancashire brewer, had already, in 1820, constructed a 
 small telescope with his own hands, being too poor to 
 purchase one. Later he improved on Lord Rosse 's methods, 
 and with a larger instrument discovered two new satellites 
 of Uranus, a satellite of Neptune, and an eighth satellite of 
 Saturn. James Nasmyth, chiefly known as the inventor of 
 the steam hammer, was also much interested in astronomy. 
 The sharpness of his vision and quality of his instrument 
 is shown by his observations of the granular structure of the 
 solar surface which no one had noticed before him. 
 
 Warren de la Rue (1815-1889), a member of the well- 
 known printing firm, was a generous supporter of many 
 scientific enterprises. In early life he had made further 
 improvements in the process of shaping concave mirrors, 
 and successfully constructed a reflecting telescope. He was 
 the first to appreciate the opportunities offered to astronomers 
 by the invention of photography, and in 1860 fitted out an 
 expedition to observe a total eclipse in Spain. The slow 
 acting plates of the time were not sufficiently sensitive to 
 show the solar corona which appears during an eclipse, but 
 
170 Britain's Heritage of Science 
 
 the red flames shooting out from the edge of the sun were 
 clearly shown in his photographs. This was an important 
 achievement, as there had been some doubt whether these 
 so-called protuberances were real phenomena belonging to 
 the sun. De la Rue also introduced the daily photographic 
 record of the sun, originally carried out at Kew, and now 
 at Greenwich and other places in the British Empire. 
 
 So far all concave mirrors used in reflecting telescopes 
 had been made of speculum metal, an alloy of tin and 
 copper, which tarnishes in the course of time. A process of 
 polishing almost as troublesome as the original shaping of 
 the surface had then to be undertaken. It was, therefore, 
 a substantial step in advance when Andrew Ainslie Common 
 (1841-1903), an engineer by profession, introduced mirrors 
 made of glass silvered at the surface, for the silvering could 
 be renewed without interfering with the shape of the surface. 
 Common acquired great skill in grinding the surfaces of glass ; 
 one of his mirrors, three feet in diameter, is now at work at 
 the Lick Observatory, and a five-foot mirror forms part of 
 the equipment of Harvard. The photograph which Common 
 obtained of the nebulae in Orion first showed the complicated 
 structure of that wonderful object, and was described by 
 Sir William Abney as " epoch-making in astronomical 
 photography." 
 
 With the introduction of dry plates a new era began for 
 Astronomy, and one of the most persevering and successful 
 workers in the field was Isaac Roberts (1829-1904), whose 
 beautiful collection of photographs of celestial objects, and 
 notably of nebulae, form a permanent record which will in 
 the future prove of the greatest value. Roberts was a builder 
 by profession. In 1890, the year after his retirement from 
 business, he moved from Liverpool to Crowborough, in 
 Sussex, where the clear air allowed him to produce his 
 finest work. 
 
 Until the middle of last century the astronomer was 
 confined in his observations to the use of the telescope ; he 
 could determine the position of stars,investigate their displace- 
 ments in the sky, and examine the structure of star clusters 
 and nebulae. Beyond this he was unable to go, until the 
 invention of the spectroscope gave him the power to extend 
 
A. Common, I. Roberts, J. N. Lockyer 171 
 
 his range in an unexpected direction. The history of science 
 can furnish no more striking instance of an almost unlimited 
 field of research suddenly opened out by a simple application 
 of a few laboratory experiments. The most successful of the 
 workers who utilized the great opportunities provided by 
 the new method of Spectrum Analysis were Sir Norman 
 Lockyer and Sir William Huggins. Lockyer's first great 
 achievement was the observation in broad daylight of the 
 prominences which up to that time could only be seen during 
 total solar eclipses. He proved that they mainly consisted 
 of glowing hydrogen. The merit of the discovery is in no way 
 diminished by its having almost simultaneously been made 
 by the French astronomer Janssen. Continuing his researches, 
 Lockyer established that the upper layer of the sun's atmo- 
 sphere, which reveals itself at the edge of the solar disc in 
 the form of a bright line spectrum, consisted mainly of the 
 lighter metals such as calcium and barium with hydrogen. 
 A bright yellow line was also universally present which 
 could not be identified as belonging to any known element. 
 Lockyer conjectured that it was due to an unknown gas 
 which he called helium; this gas, as will appear, was subse- 
 quently discovered on the earth, and is found to play a most 
 important part in modern physics. The identification of 
 terrestrial elements in the atmosphere of the sun or stars 
 ultimately proved not such a simple matter as was at first 
 supposed, because the relative intensities of the lines emitted 
 by a luminous body, and sometimes the whole spectrum, 
 changed when the conditions were altered. Lockyer turned 
 this complication to good account by trying to gauge not only 
 the substance itself, but its temperature and physical con- 
 dition in the celestial bodies. He was thus led to his meteoric 
 hypothesis of the formation and subsequent evolution of the 
 solar systems, into which it is not possible to enter here. 
 
 The most memorable discovery with which the name 
 of Huggins is connected is the measurement of the velocity 
 of stellar bodies in the line of sight. A body moving directly 
 towards, or away from, us keeps the same apparent position 
 in the sky, but just as the whistle of a locomotive alters its 
 pitch when, after approaching us, it passes and then moves 
 away, so is the wave of light received by us affected according 
 
172 Britain's Heritage of Science 
 
 as a star is receding or approaching. Huggins showed how 
 this principle can be applied to stellar motion, and thus 
 laid the foundation of a branch of astronomy which is 
 continuously growing in importance. Previously Huggins 
 had, in conjunction with W. A. Miller, carefully mapped 
 some star spectra; he also had investigated the spectra of 
 nebulae, and found that some of them consisted of glowing 
 gases. In subsequent researches he found the luminosity of 
 comets' tails to be mainly due to carbon compounds. By 
 patient and painstaking work Huggins further developed 
 the methods of obtaining photographic records of stellar 
 spectra, and the important results obtained formed the 
 starting point for the many distinguished astronomers who 
 have since taken up the work. 
 
 Before leaving the subject of Astronomy reference must 
 be made to a notable advance in the construction of re- 
 fracting telescopes. During the middle of last century, the 
 largest lens made had a diameter of sixteen inches. At the 
 exhibition of 1862, Messrs. Chance, of Birmingham, exhibited 
 glass discs of crown and flint twenty-six inches in diameter, 
 and Mr. Robert Stirling Newall (1812-1889), of Gateshead, 
 induced Messrs. Cook, of York, to construct from these 
 discs an achromatic lens of twenty-five inches. This was 
 successfully accomplished, and the telescope is now doing 
 excellent work in the Astrophysical Observatory of Cam- 
 bridge. Larger instruments have been made since, but the 
 step from sixteen to twenty-five inches is one which deserves 
 a permanent record in the history of the subject. 
 
 Modern astronomy, like other branches of science, depends 
 so much on photography that a brief account of the history 
 of this interesting and fascinating art may be here introduced. 
 
 The darkening action of light on silver chloride was first 
 discovered and investigated by the Swedish chemist Scheele. 
 W. H. Wollaston had observed that the colour of the yellow 
 gum guaiacum was altered by the action of light, and Sir 
 Humphry Davy had noted a similar effect in the case 
 of moist oxide of lead. The first actual photographic print 
 was obtained in 1802 by Thomas Wedgwood (1771-1805), 
 who threw shadows on paper moistened with a solution of 
 silver nitrate, and obtained prints giving the outlines of the 
 
W. Huggins, R. S. Newall, W. Abney 173 
 
 shadows, but his picture was evanescent, as he was unable 
 to fix it. Rudimentary as this procedure was, it contained 
 the germ of the future contact printing. Next came the 
 work of Daguerre and Niepce in France, resulting in the 
 well-known daguerreotype. In 1840 Sir John Herschel 
 introduced hyposulphite of soda as a fixing agent, and in 
 1841 Fox Talbot greatly improved Wedgwood's original 
 process, using silver iodide on paper sensitized by " gallo- 
 nitrate of silver." The introduction of collodion as a con- 
 venient vehicle holding the silver salts was first suggested 
 by G. le Gray, and put to practical use by Frederick Scott 
 Archer and P. W. Fry. In the subsequent development of 
 the dry plate important progress was due to R. Manners 
 Gordon, W. B. Bolton, and B. J. Sayce. The gelatine 
 emulsion process was used by R. L. Maddox in 1871 and by 
 J. King in 1873, but first introduced in a workable form by 
 R. Kennett in 1874. The merit of giving rapidity of action 
 to dry plates belongs to C. Bennett (1878). Further progress 
 was made by Colonel Stuart Wortley and by W. B. Bolton 
 in 1879. 1 
 
 The modern theory of photography almost entirely 
 depends on the investigations of Sir William Abney. He 
 introduced scientific methods in the measurement of the 
 sensitiveness of plates, investigated the effects of tempera- 
 ture, and showed the important influence which the size of the 
 sensitive particles had on their behaviour in different parts 
 of the spectrum. He was thus able to obtain a silver bromide 
 sensitive to the red light, and was the first to photograph 
 the infra-red rays of the solar spectrum. 
 
 A f@w words should be said about the history of colour 
 photography. Lord Rayleigh pointed out in 1887 how 
 particles of silver might be deposited in layers half a wave- 
 length apart. A film containing such layers would have the 
 power of reflecting copiously that special kind of light which 
 had served to form it. This process was actually employed 
 to reproduce natural colour effects by M. Lippmann, of 
 Paris ; but it suffers from the disadvantage that the correct 
 
 1 For a fuller account of the history of photographic processes, 
 see the article on " Photography," by Sir Wm. Abney, in the 
 " Encyclopaedia Britannica," Xlth ed. 
 
174 Britain's Heritage of Science 
 
 colours are given only when the light falls on the film at 
 the particular angle under which it was originally produced. 
 The process of Joly, introduced in 1897, is free from this 
 defect ; the principle on which it is based is the same as that 
 subsequently employed with great success by " A. Lumiere 
 et Fils," of Lyons, whose method of working, however, 
 differs materially from that of Joly. 
 
 Photography is looked upon by some as a pleasant 
 pastime, by others as an art. The chemical and physical 
 properties of matter which allow the rays of light to form 
 a latent picture, to be subsequently developed, fixed and 
 printed, are in themselves a fascinating study, and there is 
 no limit to the utility of photography as an aid hi scientific 
 investigations. Here, as elsewhere, science exerts its greatest 
 charm when it forms a connecting link between the ordinary 
 interests of our daily life and the abstract questions which 
 engage the attention of academic philosophers. Thus, 
 nearly all problems of geophysics have both an intensely 
 practical and a deeply theoretical side. The commonplace 
 necessity of defining the boundaries of land leads to the 
 demand for accurate maps, and this, again, opens out 
 investigations on the figure and size of the earth. One 
 question suggests another, until abstruse mathematical pro- 
 blems acquire a special interest owing to their connexion 
 with the history of the world's formation. Similarly, fore- 
 casts of weather that shall be helpful to the farmer demand 
 a study of aero -dynamics, involving mathematical treatment, 
 combined with experimental work of high precision, and 
 the ordinary phenomenon of the tides takes us inevitably to 
 problems demanding the genius of such men as Kelvin and 
 George Darwin. 
 
 The ordinary making of maps is a task belonging to the 
 Government services, and it is to officers in the Army and 
 the officials in charge of the various surveys at home, or in 
 the colonies, that we are mainly indebted for our knowledge 
 of geodesy. Such work, important as it is, often receives 
 insufficient acknowledgment because, being co-operative, the 
 share of each man cannot always be clearly defined. But a 
 few examples may be given. 
 
 Captain Henry Kater (1777-1835), the son of a sugar 
 
Henry Kater, Edward Sabine 175 
 
 baker, entered the army and joined his regiment in Madras. 
 He had a taste for mathematics, and became assistant to 
 William Lambton, who was conducting a survey of the 
 Malabar and Coromandel coast. After his return to England 
 he took part in the British survey, and turned his attention 
 to the improvement of accurate geodetic and astronomical 
 measurements. Kater 's pendulum is an ingenious arrange- 
 ment for eliminating the errors due to an irregular distribu- 
 tion of mass in the ordinary pendulum when it is used for 
 gravity measurements. The determination of the difference 
 in longitude between Paris and Greenwich gave him further 
 opportunities for exercising his ingenuity in devising new 
 methods of observation. In 1827 Kater was elected 
 Treasurer of the Royal Society, and held that position 
 during three years. 
 
 General Sir Edward Sabine (1788-1883) organized world- 
 wide observations on gravity, and the elements of terrestrial 
 magnetism. The importance of his work calls for a short 
 account of his life. He was educated at the Woolwich 
 Military Academy, and received a commission in the Royal 
 Artillery at the age of fifteen. After seeing much active 
 service, he returned to England in 1816. Shortly afterwards 
 he was appointed astronomer to the Arctic Expedition which 
 sailed under Ross in search of the North-West Passage, and 
 after his return home took part in a second Arctic Expedition 
 under Edward Parry. In 1823 he undertook an extensive 
 journey to measure the value of the gravitational force at 
 different points of the earth's surface. In 1830 he was recalled 
 to active service, the condition of Ireland necessitating an 
 increased military establishment. He stayed in Ireland 
 until 1837, using part of his time to organize the first 
 magnetic survey of the British Isles. During his subsequent 
 life, which was entirely devoted to science, he was indefa- 
 tigable in getting magnetic observatories established in 
 many countries, and promoting further pendulum observa- 
 tions, more especially in India, where ever since they have 
 formed an important part of the Government Survey's 
 work. Sabine was Treasurer of the Royal Society from 
 1850 to 1861, and during the following ten years he filled 
 the position of President. 
 
176 Britain's Heritage of Science 
 
 Most distinguished among the Directors of the British 
 Survey was Alexander Ross Clarke (1828-1914), who has 
 given us the most accurate determination so far obtained of 
 the size and figure of the earth. He was concerned in several 
 of the principal measurements of meridional arcs, and in 
 1860 was entrusted with the comparison of the national 
 standards of different countries, a most delicate piece of 
 work, which required the building of a separate room at the 
 Ordnance Survey Office. 
 
 Our account of the progress of Meteorology must be short 
 and incomplete, but we may recall William Charles Wells 
 (1757-1817), the London doctor who first gave the correct 
 explanation of the formation of dew, Luke Howard (1772- 
 1864), who classified the clouds, and John Apjohn (1796 
 -1880), who showed how to calculate the humidity of the 
 air from observations with the wet and dry bulb thermo- 
 meter. We must also remember the wonderful balloon ascents 
 of James Glaisher (1809-1903), who, reaching a height of 
 over 30,000 feet, obtained the first observation of the 
 upper air. A kite was used in meteorological work as early 
 as 1749 by Alexander Wilson, of Glasgow, and its modem 
 application dates from the experiments made in England 
 in 1882 by E. D. Archibald. One of the most enthusiastic 
 workers in Meteorology, Alexander Buchan (1829-1907), 
 studied at Edinburgh and was engaged for some time as a 
 school teacher, but in 1860 he was appointed secretary of 
 the Scottish Meteorological Society, and was henceforward 
 able to devote himself entirely to his favourite study. His 
 work on atmospheric circulation possesses considerable im- 
 portance, and he was also one of the chief promoters of the 
 observatory which, during a number of years, stood on the 
 summit of Ben Nevis. 
 
 A discovery of great value to meteorology was made by 
 John Aitken, of Falkirk, who in 1883 observed that water 
 vapour always requires some nucleus to condense upon. 
 The most common nuclei are the dust particles which are 
 always present in the atmosphere, and every drop of rain 
 or particle of fog contains some solid contamination at its 
 centre. The best protection against fog is, therefore, the 
 purification of the atmosphere. The condensation of water 
 
A. Ross Clark, A. Buchan, G. H. Darwin 177 
 
 on solid matter has been utilized by Aitken in constructing a 
 little instrument which allows us to count the number of 
 particles of solid matter contained in the air. He found 
 that even the cleanest air will contain about 20 particles per 
 cubic centimetre, while in London or Paris the number 
 generally rises to well over 100,000. 
 
 The work of Sir George Howard Darwin (1845-1912) 
 may serve to illustrate how a geophysical problem which in 
 its main features is easily understood, is found to involve 
 the whole history of the Universe as soon as we pass from 
 the general explanation to the more detailed study required 
 to give accurate numerical results. That the tides of the 
 ocean are due to the gravitational attraction of the sun and 
 moon was known already to Newton, and it can be shown 
 without difficulty that the explanation agrees in a general 
 way with observations. But, if we wish to formulate a 
 mathematical theory, we must begin by simplifying the 
 problem, and assume the earth to be a rigid solid sphere 
 covered entirely by a layer of water having the same depth 
 everywhere. The statement of this problem is simple enough, 
 but its solution becomes already complicated when the com- 
 bined attractions of the sun and moon are considered. Yet 
 we are not anywhere near the real tides on the real earth. 
 The ocean does not cover the whole globe, it is not of 
 uniform depth, and the solid core of the earth is not 
 absolutely rigid, but appreciably yields to the disturbing 
 forces. When we try to take account of these complications, 
 even in the roughest manner, we see that there must be a 
 frictional effect tending to retard the rotation of the earth; 
 this involves a re-acting force on the moon, and it can be 
 shown that this must slowly drive it further away. Hence 
 we conclude that there must have been a time when the 
 moon was nearer, and the earth rotated more rapidly, and, 
 looking still further back, this brings us to the time when 
 the moon may have formed part of the earth and ultimately 
 separated from it. Can we form an approximate estimate of 
 that time ? Such are the questions which occupied George 
 Darwin during a considerable part of his life. The whole 
 problem does not, of course, affect the earth only, but 
 concerns every celestial body. It opens out the whole 
 
 If 
 
178 Britain's Heritage of Science 
 
 question of the stability of fluid gravitating and rotating 
 bodies. George Darwin's own contributions to the subjeci 
 have materially helped to establish a scientific basis for th( 
 treatment of a subject, fundamental in cosmogony, whicl 
 has fascinated the most powerful mathematical brains ir 
 recent times. For his other important researches the readei 
 must be referred to his collected works, but some reference 
 may be made to the time which he ungrudgingly devotee 
 to assist all efforts which aimed at an organized co-ordi 
 nation of scientific work, and co-operation between differenl 
 scientific bodies. During thirty years he was a member oj 
 the Meteorological Council, and of the Treasury Committee 
 which superseded it. He actively supported international 
 scientific undertakings, and more especially the Internationa 
 Geodetic Association, on which he represented England foi 
 many years; in 1909 he was elected its President. 
 
 Several instances have already been given of the reci- 
 procal relation between utilitarian objects and abstract 
 scientific truth, and a further example is furnished by the 
 work of John Milne (1850-1913). After studying Geology 
 and Mineralogy at King's College and the Royal College ol 
 Mines, he gained some practical experience in the mines 
 of Cornwall and Lancashire, extending his knowledge fry 
 a course of study at Freiberg, and a visit to the mining 
 districts of Germany. In 1875 he was appointed Professor 
 of Geology and Mining at the Imperial College in Tokio, 
 where he was at once confronted with important practical 
 problems arising out of the frequent occurrence of earth- 
 quakes in Japan. In order to construct buildings and bridges 
 so that they should resist the movements of the foundations 
 on which they are built, it is necessary to study, in the 
 first instance the nature of these movements. Milne was 
 attracted by both the practical and theoretical side of the 
 investigation, but as no suitable instruments were available 
 for the purpose, he supplied the want, and for a number of 
 years his seismographs became the standard instruments. 
 Important questions immediately suggested themselves, and 
 Milne became the founder of a new science. After his return 
 to England, he organized, with the assistance of the British 
 Association, in different parts of the Empire and other 
 
Sir George Darwin, John Milne 179 
 
 countries, a large number of suitable stations at which earth 
 tremors were accurately observed. The records of the obser- 
 vations, interpreted partly by Milne himself and partly by 
 other seismologists, proved to be of the highest interest. 
 The waves propagated through the earth from the centre 
 of a large disturbance are found to be noticeable with 
 delicate instruments all over the world. We now know that 
 the general movement spreads out from the centre of a 
 disturbance in three distinct waves, each propagated with its 
 own peculiar velocity. The first is a longitudinal wave, which 
 passes through the earth like a sound wave does through air. 
 The second is a transverse wave, arriving somewhat later; 
 both these waves reach us by transmission across the body 
 of the earth. A third set of waves, which in the records 
 appears as an oscillation of larger amplitude and longer 
 period than the rest, spreads over the surface of the earth 
 with a velocity of about 3*5 kilometres per second. The 
 interval between the arrival of these three types of waves 
 serves to indicate the distance of the centre of the dis- 
 turbance, and Prince Galitzin has shown how the direction 
 of the first impulse gives us the direction in which that 
 centre lies. Hence it is now possible to locate a distant 
 earthquake by means of observations taken at any one 
 place where it is still able to affect the delicate instruments 
 which, by a self-registering arrangement, are always ready 
 to record the waves. 
 
 The scientific interest of the subject lies in the information 
 it is likely to yield on the internal constitution of the earth ; 
 for some of the waves that reach us, if the centre of dis- 
 turbance be far away, have passed through deep regions, 
 approaching in some cases the actual centre of the earth. 
 The manner in which their path bends round owing to 
 changes in the elastic properties of the earth at different 
 depths is indicated by the direction and magnitude of the 
 oscillation which the wave impresses on our instruments. 
 It is difficult to interpret completely the observed effect, 
 but the investigation has already advanced sufficiently to 
 .how that important results may still be expected from that 
 jtudy of earth tremors which Milne initiated. 
 
 The survey of the history of British physical science has 
 
 M 2 
 
180 Britain's Heritage of Science 
 
 now been brought to the period when men of the present time 
 were called upon to receive the heritage, and do their best 
 to hand it on to then* successors. The problems of to-day 
 may not be seen in their right perspective; yet the last 
 thirty years have been so exceptionally fertile in new dis- 
 coveries that we may anticipate with confidence the judg- 
 ment of posterity on those great advances which have 
 revealed an entirely new class of phenomena, and enabled 
 us to form views on the structure of matter which, at any 
 rate, may be considered to be an advance on our previous 
 knowledge. A very brief summary, however, must suffice. 
 
 In the seventies of last century it was generally thought 
 that our power to discover new experimental facts was 
 practically exhausted. Students were led to believe that 
 the main facts were all known, that the chance of any 
 new discovery being made by experiment was infinitely 
 small, and that, therefore, the work of the experimentalist 
 was confined to devising some means of decicling between 
 rival theories,- or by improved methods of measurement 
 finding some small residual effect, which might add a more 
 or less important detail to an accepted theory. Though it 
 was acknowledged that some future Newton might discover 
 some relation between gravitation and electrical or other 
 physical phenomena, there was a general consensus of opinion 
 that none but a mathematician of the highest order could 
 hope to attain any success in that direction. Some open- 
 minded men like Maxwell, Stokes, and Balfour Stewart, 
 would, no doubt, have expressed themselves more cautiously, 
 but there is no doubt that ambitious students all over 
 the world were warned off untrodden fields of research, 
 as if they contained nothing but forbidden, though perhaps, 
 tempting, fruit. When Crookes, in the year 1874, constructed 
 his radiometer, it looked for a short time as if he had 
 definitely disposed of such timid and discouraging opinions; 
 but, on the contrary, he seemed only to have confirmed 
 them. For the apparent repulsion of light observed in the 
 radiometer was found to be due to the residual gas in his 
 exhausted vessels, and could be explained by the then 
 accepted kinetic theory. He had, no doubt, by greatly 
 improved methods, discovered a new effect, but this had 
 
Lord Rayleigh, Sir William Ramsay 181 
 
 only led to perfecting an established theory in an important 
 detail. 
 
 The new era begins with Lord Rayleigh 's discovery of 
 argon. The research which led to it was originally under- 
 taken with a view to testing the hypothesis of William Prout 
 (1786-1850), a London doctor, according to whom the atomic 
 weights of all chemical elements are exact multiples of that 
 of hydrogen. In the course of an accurate determination of 
 the density of nitrogen it was found that, when the gas is 
 prepared from air by removing all other known constituents, 
 it has a density half per cent, greater than when it is obtained 
 directly from ammonia. Rayleigh then drew the conclu- 
 sion that the discrepancy was due to some unknown body, 
 probably a new gas in the atmosphere heavier than nitro- 
 gen. While the research was advancing successfully, William 
 Ramsay joined the investigation, and the final results were 
 published by Rayleigh in conjunction with him. 
 
 Sir William Ramsay (1852-1916) then entered into that 
 period of his activity in which discoveries rapidly succeeded 
 each other. Sir Henry Miers drew his attention to a certain 
 mineral which was known to give out an inert gas when 
 dissolved in an acid. This gas was supposed to be nitrogen, 
 but Miers thought it might turn out to be argon. Ramsay 
 extracted the gas, examined it with a spectroscope, and to 
 his surprise found the bright yellow line which appears so 
 brilliantly in the light emitted all round the edge of the 
 sun and in its protuberances. The gas proved, therefore, 
 to be identical with the one spectroscopically discovered 
 many years previously by Sir Norman Lockyer, and named 
 by him " helium." Subsequently, by applying the process 
 called " fractional distillation " to liquid air, Ramsay could 
 isolate three additional elements : krypton, xenon, and 
 neon. 
 
 In the meantime, experiments on the discharge of 
 electricity through gases had made rapid progress. His 
 experiments with the radiometer had led Crookes to intro- 
 duce great improvements in the construction of the mercury 
 pumps used to obtain high vacua in glass vessels. By sending 
 electric currents of high potentials through such vessels, 
 Crookes investigated the vivid phosphorescent luminosity 
 
182 Britain's Heritage of Science 
 
 which appears near the negative electrode. Important 
 results were obtained in these researches. Investigations by 
 other observers which cannot here be described, led to the 
 conclusion that gases, which ordinarily are insulators, could 
 in various ways be made to conduct electricity, and the 
 phenomena suggested that the conductivity was due to the 
 formation of carriers analogous to the ions which normally 
 exist in liquids. Gases, in fact, could be ionized. The 
 stage was now reached where experiments definitely pointed 
 to the conclusion that electricity, like water, had an atomic 
 constitution. To furnish the proof, it was necessary to 
 show that the atomic charge was the same in all cases. The 
 experiments with liquids gave no direct measure of this 
 charge, but they allowed us to determine its ratio to the 
 mass of the carrier. That carrier in liquids is the chemical 
 atom, and it was natural at first to suppose that the same 
 would be the case in gases ; if so, the matter could be tested, 
 as we know the relative masses of different chemical atoms. 
 The first experiments made in that direction led to no 
 decisive results, though they supplied a method which proved 
 useful. The question was finally solved by Sir Joseph 
 Thomson, who proved that the carrier of negative electricity 
 had a mass much smaller than that of a chemical atom; 
 ultimately it was found that, near the kathode of an electric 
 discharge through gases, it is actually the atom of negative 
 electricity which is set free, and acts as carrier. 
 
 Thomson further determined the charge of the electron, 
 the name given to the atom of electricity by Johnstone 
 Stoney (see p. 139), and found it to agree with that which 
 may indirectly be derived from the electrolysis of liquids. 
 
 There can be no doubt that Sir Joseph Thomson's ex- 
 periments will be looked upon in future as a landmark in 
 the advance of science as great as those that have been 
 described in our first chapter. 
 
 Thomson's discovery was announced at the British 
 Association meeting of 1899. Since then our ideas have 
 advanced rapidly, and we now consider corpuscles of positive 
 and negative electricity to be the elemental atoms from which 
 all matter is built up. In the origination and development 
 of this theory Sir Joseph Larmor has taken an active part. 
 
Sir J. J. Thomson, Sir E. Rutherford 183 
 
 During the last few weeks of the year 1896 some remark- 
 able experiments of W. C. Roentgen revealed to us a new 
 and quite unexpected class of phenomena. The electric 
 discharges in a highly-exhausted vessel were found to be 
 capable of generating a radiation now known to be due 
 to very short waves which could penetrate many bodies 
 opaque to ordinary light. This was the X-radiation which 
 has proved to be of such enormous value in surgery. Their 
 investigation indirectly led to our knowledge of a still more 
 remarkable class of phenomena. The French physicist, 
 Becquerel, while trying to find whether the sun emitted 
 X-rays, observed a most surprising effect, which could only 
 be accounted for by assuming the existence of a new form 
 of radiation, essentially different from that of the X-rays. 
 Separating the substance that was mainly responsible for it, 
 M. and Mme. Curie discovered the new metal radium. This 
 is the typical radio-active element, but two other known 
 chemical elements uranium and thorium proved to resemble 
 radium in its peculiar properties. A new science then opened 
 out. 
 
 The effects of radio-activity show themselves by their 
 power of ionizing air and affecting photographic plates, but 
 the first results were extremely puzzling, and experimenters 
 were being led away on a wrong track when Sir Ernest 
 Rutherford took up the work. He first discovered that 
 thorium and radium gave up gases the so-called emana- 
 tions which themselves were radio-active. It was the 
 disturbing effect of these gases which, diffusing through 
 the air of the laboratory, had affected the instruments, and 
 led Becquerel and Curie astray; it had to be separated 
 from that of the parent substance before the different 
 phenomena could be disentangled. By a series of remarkable 
 experiments, Rutherford soon cleared up the essential features 
 of radio-activity. In conjunction with Frederick Soddy he 
 then developed his theory, which now stands on a firm 
 basis. Radio-activity was shown to be the result of the 
 ejection of corpuscles from the parent body, which thereby 
 became transformed into another substance which was 
 generally itself subject to further decomposition through the 
 emission of other corpuscles. The decomposition proceeds 
 
184 Britain's Heritage of Science 
 
 at a perfectly definite rate, and the life of any radio-active 
 substance can, therefore, be foretold. The ejected particles 
 consist either of one or more negative electrons (/3 particles), 
 or positively charged corpuscles (a particles); frequently 
 both are emitted. The a particle carries twice the charge 
 of an electron, and weighs about twice as much as an 
 atom of hydrogen : that is to say, as much as a helium atom. 
 Rutherford formed the idea that the two might be identical 
 and this was experimentally confirmed by Sir William Ramsay. 
 The emanation of radium which emits an a particle in its 
 decay was introduced into, and kept in an exhausted tube for 
 several days, when it was found that the spectrum line of 
 helium could be clearly seen, though no helium had originally 
 been present. This experiment, which gave the proof of 
 Rutherford's surmise, was an historical event, as it supplied 
 the first definite example of the decomposition of a so-called 
 chemical element. For the emanation possesses all the 
 characteristics of such an element and was shown to decom- 
 pose spontaneously, helium being one of the products. 
 The subsequent development of radio-active experiments 
 and theories confirmed the original ideas, and many new 
 and interesting facts were brought to light. 1 These must be 
 passed over, and we might here close our account, were it 
 not for the brilliant researches of a young man, who promised 
 to become one of the great investigators of his time. 
 
 Henry Moseley (1887-1915) was the grandson of Canon 
 Moseley, a distinguished mathematical physicist, and the 
 son of Professor H. N. Moseley, at one time Linacre Pro- 
 fessor of Zoology at Oxford. He took his degree at Oxford, 
 but received his scientific training mainly from Rutherford 
 at Manchester. After Laue, at Munich, had proved the 
 existence of a diffraction effect of crystals on X-rays, and 
 Professor William Henry Bragg had developed and improved 
 the methods of observation, Moseley set himself the task of 
 determining the fundamental vibrations of the atoms which 
 give rise to the X-rays. The research required exceptional 
 experimental skill, and great powers of devising new methods 
 
 1 For a detailed account of these investigations see Rutherford, 
 " Radio-activity." 
 
Ernest Rutherford, Henry Moseley 185 
 
 of investigation, and the result proved of the highest value. 
 The wave-lengths to be measured are less than the thousandth 
 part of that of visible rays, and in that region the arrange- 
 ment of the lines was found to be the same for all elements ; 
 but proceeding from lower to higher atomic weights, the 
 spectrum was bodily displaced by a definite amount towards 
 the shorter wave-lengths. To see the full bearing of this 
 investigation, we must refer to the theory which Rutherford 
 had formed on the constitution of atoms, based mainly on 
 his experiments on the scattering of a particles by molecules 
 of matter. According to that theory, each atom possesses a 
 positively charged nucleus of exceedingly small dimensions. 
 The nucleus is made up of definite numbers of unit charges, 
 and if we arrange the elements in order of their atomic 
 weights, it is natural to suppose that the total charge 
 increases by one unit as we pass from one element to the next. 
 We may take the atomic number (meaning the number of 
 charges) as the characteristic of each element, and deal, 
 therefore, with figures which are successive integers, rather 
 than with the irregularly increasing numbers representing the 
 atomic weights. Moseley 's experiments prove that the high 
 frequency spectrum of the elements which he examined is 
 completely defined by the atomic number. It may be antici- 
 pated that this will prove to be the foundation of a new and 
 more precise chemistry, as other properties will be certain 
 to be intimately connected with the forces which regulate the 
 spectra. In confirmation of this, it may be stated that 
 Moseley in fixing the atomic number had to invert the order 
 in the case of potassium and argon, and that of cobalt and 
 nickel, and in both instances it is found that the chemical 
 properties agree with the spectroscopic evidence, and not 
 with that of the order of atomic weights. 
 
 Moseley's results, while showing that all elements can be 
 placed in a certain definite order almost identical with that 
 of the atomic weights, allow us also to discover the gaps 
 which we may confidently expect to see filled up by hitherto 
 undiscovered elements. Eighty-three are known at present 
 and Moseley's table of results shows nine gaps between 
 argon and the heaviest of the metals, uranium. The total 
 number of elements reached, when the gaps are filled, will be 
 
186 Britain's Heritage of Science 
 
 ninety-three; but some authorities believe in the existence 
 of two further elements lighter than helium. 
 
 Moseley's magnificent researches came to a sudden and 
 tragic end. On the threshold of a career of singular promise, 
 looking towards a future pregnant with discoveries that 
 could not fail to fall to his genius and enthusiasm, he answered 
 the call to arms at the outbreak of the war; and a Turkish 
 bullet cut short a life precious to the peaceful glory of his 
 country, but gladly surrendered in its hour of need. That 
 also is a heritage which will go down to posterity. 
 
187 
 
 CHAPTER VI 
 
 (Physical Science) 
 
 SOME INDUSTRIAL APPLICATIONS 
 
 IT is not intended here to catalogue, much less to discuss, 
 the multitude of practical applications of science which 
 have originated in this country during the last century. To 
 mention merely the manufacture of steel, the building of 
 bridges, and the evolution of the modern steam-engine is 
 sufficient to illustrate the all-pervading influence of science 
 on our industries. 
 
 The scientific production of steel originated with Ben- 
 jamin Huntsman (17041776), a clockmaker of Doncaster, 
 who discovered the process of making cast steel by melting 
 in crucibles. Starting works in Sheffield, he was the first to 
 introduce a material of uniform temper and composition 
 which could in the modern sense be termed steel. Much 
 might be said on the more recent developments of the steel 
 industry by Henry Bessemer (1813-1898), and on other in- 
 ventions, such as Sir Charles Parsons' steam-turbine, one of 
 the greatest triumphs that engineering skill has ever achieved. 
 But we must content ourselves with a few selected examples 
 illustrating the effects of pure scientific research on that 
 complex organization of the community which usually goes 
 by the name of civilization. 
 
 So much in our modern life depends on the facilities for 
 rapid mutual intercourse that it is curious to note how 
 new devices have often supplied the means before there 
 was a demand. The capacity of inventing outpaced the 
 power of the imagination to understand the use of the inven- 
 tion : the supply had to create the demand. Thus, when 
 Sir Francis Ronalds (1788-1873) submitted to the Govern- 
 ment in 1816 the design of an electric telegraph which he 
 
188 Britain's Heritage of Science 
 
 had actually tried and found to work with a length of eight 
 miles of wire, the reply of the Secretary of the Admiralty 
 was that <v telegraphs of any kind are now totally unnecessary 
 and that no other than the one now in use will be adopted." 
 The word " now " seems to have referred to the conclusion of 
 the French war, and the telegraph mentioned as being in use 
 was the semaphore. 
 
 Ronalds was the son of a London merchant ; his method 
 of transmitting signals consisted in charging and discharging 
 an electroscope through a long wire. In his experiments he 
 used a length of eight miles of wire, properly insulated and 
 embedded in the soil of a garden in Hammersmith. The 
 distinguishing feature of his apparatus consisted in an arrange- 
 ment founded on the same principle as the one so successfully 
 employed in the type-printing arrangement invented at a 
 much later date by Hughes. Two discs bearing the letters 
 of the alphabet near their circumferences were made to 
 rotate with the same speed at the two ends of the line. The 
 electroscope placed at the receiving end was discharged from 
 the sending end. The sender watched the moment when 
 the required letter passed a certain position, and the same 
 letter passing the corresponding position at the receiving 
 end at the moment of discharge could therefore be read off. 
 The two discs were adjusted by means of a signal before the 
 message was sent, and it only remained to ensure that the 
 discs rotated synchronously during the time it took to send 
 the message. Bits of the original wire with its insulating 
 covering were dug out later, and are now preserved in the 
 Science Museum at South Kensington. 
 
 When the electromagnetic effects of currents had been 
 discovered, experiments by Gauss and Weber, Schilling and 
 Steinheil showed how they could be utilized in transmitting 
 signals. These experiments became known in England 
 through William Fothergill Cooke (1806-1879), knighted in 
 1869) who, in conjunction with Wheatstone, set to work to 
 devise a system of telegraphy that could be commercially 
 successful. The main difficulty was to reduce the number of 
 wires, which were at first thought to be necessary for indi- 
 cating the twenty -five letters; in this respect Ronalds had 
 been ahead of his successors. The difficulty was overcome 
 
Telegraphy 189 
 
 by an alphabet of signs introduced by the American inventor 
 Morse, but an alternative one-wire system of Cooke and 
 Wheatstone in which the letters are directly indicated on a dial, 
 though much slower in its working, continued to be employed 
 in the British Telegraph Service at stations where it was 
 difficult to obtain operators sufficiently practised in the 
 Morse code. Subsequent improvements in telegraphy over 
 land lines are mainly of technical interest. 
 
 An entirely new set of problems arose when submarine 
 cables had to be laid across the oceans. As water is not an 
 insulator like air, the conductor which serves for the trans- 
 mission of the message has to be surrounded by a non- 
 conducting material like guttapercha. The copper wire inside 
 and the water outside separated by an insulating substance 
 then act like a condenser which must be charged up before a 
 steady electric current can flow through the wire. This 
 retards the transmission, and otherwise complicates the 
 effects, so that the ordinary telegraphic apparatus become 
 useless. Lord Kelvin's inventive genius soon supplied a 
 suitable instrument, but there were other dangers ahead, such 
 as the enormous mechanical stresses to which the cables are 
 exposed, and the destructive effects of submarine boring 
 animals. The credit of overcoming these difficulties is largely 
 due to Robert Newall, whose name has already been 
 referred to in connexion with Astronomy. As a practical 
 engineer, Newall had improved the manufacture of wire 
 rope to such an extent that quite a new industry may be 
 said to have originated through his efforts. He used the 
 experience gained by introducing wires to strengthen the 
 cables and inventing suitable appliances for paying them out. 
 The first commercially successful cable was laid across the 
 Straits of Dover in 1857, and the possibility of telegraphic 
 communication between Europe and America was then 
 opened out. In July, 1857, a cable was ready, and the shore 
 end was fixed at Valentia ; but the cable snapped when 
 380 miles had been laid. In the following year, after a further 
 failure, a cable was finally stretched across the Atlantic ; but, 
 unfortunately, Kelvin's instructions were ignored and high 
 potential currents were used to transmit the messages, 
 with the result .that the insulation was completely ruined. 
 
190 Britain's Heritage of Science 
 
 The next attempt, made after an interval of eight years, 
 was again unsuccessful; but in 1866 the Or eat Eastern 
 laid its cable without mishap, and was even able to pick up 
 the lost end of the one that had broken in the previous year. 
 Since then submarine cables, mostly manufactured in Eng- 
 land, have rapidly increased, and their total length now at 
 work would, if joined end to end, be able to pass ten times 
 round the equator. 
 
 The success of cables depends so much on the durability 
 of the insulating material that this seems to be the place 
 for attention to the services of Thomas Hancock (1786- 
 1865), the founder of the india-rubber trade in England. 
 His work is well described in the " Dictionary of National 
 Biography," from which the following account is with a 
 few omissions transcribed. Observing that two freshly 
 cut surfaces of india-rubber readily adhered by simple 
 pressure, Hancock was led to the invention of the " masti- 
 cator," as it was afterwards called, by the aid of which 
 pieces of india-rubber were worked up into a plastic and 
 homogeneous mass. With the invention of this process, 
 which was perfected about 1821, the india-rubber trade 
 commenced. Eventually, Hancock became a partner in 
 the firm of Charles Macintosh and Company, though he still 
 carried on his business in London. In 1842 specimens of 
 " cured " india-rubber, prepared in America by Charles 
 Goodyear according to a secret process, were exhibited in 
 this country. Hancock investigated the matter, and dis- 
 covered that when india-rubber was exposed to the action 
 cf sulphur at a certain temperature a change took place; 
 he thus obtained " vulcanized " india-rubber. This was 
 patented in 1843. Although Hancock was not the inventor 
 of vulcanizing in the strictest sense of the word, he first 
 showed that sulphur alone is sufficient to effect the change, 
 whereas Goodyear employed other substances in addition. 
 Hancock also discovered that, if the vulcanizing process be 
 continued and a higher temperature employed, a horny 
 substance, now called vulcanite or ebonite, is produced. 
 
 David Edward Hughes (1831-1900), whose name has 
 already been mentioned above, was born in London, but 
 his parents emigrated to the United States when he was 
 
William Thomson, Lord Kelvin 
 
T. Hancock, D. E. Hughes, W. Sturgeon 191 
 
 seven years old. He was connected for a time with a college 
 in Kentucky, first as Professor of Music and then as a 
 teacher of Natural Philosophy, but gave up the academic 
 career, at the age of twenty-three, to supervise the manu- 
 facture of the type-printing machine which he had invented. 
 Everyone is now familiar with that perfect little instrument 
 which distributes typed messages simultaneously all over a 
 city. The income which the inventor derived from it gave 
 him the desired leisure for further scientific investigations. 
 His most important discovery is that of the microphone, in 
 which two pieces of carbon are in loose contact, making 
 an electric connexion that is exceedingly sensitive to the 
 slightest disturbance caused by a wave of sound or an 
 electric impulse. The carbon contact was soon introduced 
 into telephone transmitters, and helped much to make tele- 
 phones serviceable for ordinary use. In observing the effect 
 of electric impulses in carbon contacts Hughes anticipated 
 the invention of the " coherer," which made the trans- 
 mission of wireless electric messages to great distances 
 possible. It is, indeed, related that, so far back as 1879, 
 Hughes could detect by the microphone " electric impulses " 
 at a distance of 500 yards. 1 The researches on the microphone 
 and on another useful instrument, the " induction balance," 
 were carried out in England, where Hughes spent the later 
 part of his life. 
 
 All industrial applications of electricity are based on 
 Faraday's discoveries, and Sturgeon's invention of the electro- 
 magnet. After it had been shown experimentally by the 
 former that an electric current is produced when a wire is 
 moved in a magnetic field, it was pretty obvious that appliances 
 could be constructed for generating currents by mechanical 
 means. There is no indication that at first anyone was aiming 
 at currents of great intensity; machines were constructed 
 partly on account of their scientific interest and partly to 
 be used for purposes of telegraphy. Sturgeon was the first to 
 attack the inverse problem of using a current to do mecha- 
 nical work, and it has been described in our first chapter 
 how Joule started his work by trying to improve the 
 
 1 " Encyclopaedia Britannica." 
 
192 Britain's Heritage of Science 
 
 efficiency of electromagnetic engines. Between 1850 and 
 1860 many attempts were made to increase the intensity of 
 electric currents obtained by electrodynamic induction, but 
 the turning point came when, in the spring of 1867, Henry 
 Wilde, of Manchester, showed some remarkable experiments 
 in the rooms of the Royal Society. In the previous year he 
 had already described the main principle on which he relied 
 to increase the intensity of currents that could be obtained 
 by electromagnetic induction. A machine constructed accord- 
 ing to a model made by Werner Siemens, in which an armature 
 rotated in a magnetic field produced by a permanent magnet, 
 generated an electric current which fed a second and larger 
 machine in which the permanent magnets were replaced by 
 electromagnets. These were excited by the first current 
 and a much stronger magnetic field was produced : a more 
 powerful current was consequently obtained. This was led 
 in a third machine round still larger masses of iron, which 
 were thus magnetized, and finally a current emerged showing 
 effects of surprising intensity. A piece of iron half-an-inch 
 thick melted and burned when the current was made to pass 
 through it, and a rod of platinum two feet long and a quarter 
 of an inch in diameter was also seen to melt. A steam engine 
 of 15 h.p. was required to drive the shafts of the machines. 
 Eye-witnesses testify to the great impression created by 
 these experiments, and there can be little doubt that the 
 public then first began to recognize the potentialities of the 
 electric current. Rapid advances were quickly made, and 
 the modern " dynamo-machine " was soon evolved ; Wilde 
 himself had already called his machines by that name. 
 
 As soon as commercial interests are involved in scientific 
 appliances, new problems of an economic nature arise. The 
 weight of metal to be put into the different parts of the 
 machinery has to be adjusted so as to obtain the best 
 results at the least cost, and other matters have to be con- 
 sidered. Apart from some contributions by Lord Kelvin, it 
 may be said that the economics of the dynamo-machine 
 depend almost entirely on the researches of John Hopkinson, 
 who, perhaps, more than any other British man of science, 
 combined the commercial faculty with the highest scientific 
 attainments. 
 
H. Wilde, J. Hopkinson, J. A. Ewing 193 
 
 John Hopkinson (1849-1898) was born in Manchester, 
 and after studying two years at Owens College entered 
 Trinity College, Cambridge. He graduated in 1871 as senior 
 wrangler, and in the following year was engaged by Messrs. 
 Chance Brothers, glass manufacturers, at Birmingham, as 
 engineering manager. In this position he devoted himself 
 to the improvement of lighthouse illumination, and intro- 
 duced the system of group flashing lights which is now 
 extensively used. In 1878 he settled in London as consulting 
 engineer, and during the next few years conducted his 
 classical researches on the efficiency of dynamo-machines. 
 These were completed later, in conjunction with his brother 
 Edward, by laying down the general principles by which the 
 performance of any machine may be predicted from its 
 design. Another important contribution to electric lighting 
 was his invention of the three-wire system of electrical 
 distribution. 
 
 The efficient working of most of our electrical machinery 
 depends on the magnetic properties of iron, and mention 
 must, therefore, here be made of the valuable investigations 
 of Professor J. A. Ewing, who first clearly pointed out the 
 inevitable dissipation of energy which occurs when a piece of 
 iron is subject to rapidly alternating magnetic forces, as it is, 
 for instance, in a transformer. Owing to a property of iron 
 which he called hysteresis, and which is a kind of internal 
 viscosity brought into action by the rapidly changing orienta- 
 tion of magnetic molecules, some of the energy will always be 
 converted into heat, and is lost as useful work. In other 
 respects also, Ewing has added much to our knowledge of 
 magnetism. 
 
 Our electrical industry owes much to William Edward 
 Ayrton (1847-1908), who was the first to introduce sound 
 methods of instruction in applied electricity. He was 
 the most successful and, for a time, the only teacher of the 
 subject. He organized the laboratories at Finsbury College, 
 and at the Central College, Kensington. Men came from 
 all parts of the world to be trained by him, and he knew how 
 to infuse his students with the spirit of research. In the 
 early days of the industry, the measuring instruments, 
 though suitable for a physical laboratory, could not easily 
 
 N 
 
194 Britain's Heritage of Science 
 
 be moved, or protected against the disturbing effects to 
 be expected in a large workshop. Ayrton recognized the 
 want, and in conjunction with Professor ^ohn Perry designed 
 a number of reliable and practical instruments that could be 
 used in a factory. Some of these inventions have proved of 
 permanent value. 
 
 The applications of chemistry to the necessities of the 
 nation are predominant in times of war, and hardly less 
 universal in times of peace. Two great industries stand out 
 on account of their importance, enhanced as it is by the 
 interest attached to, and the instructive contrast presented 
 by, their historical development. While the alkali manu- 
 facture which has been prosecuted so successfully in this 
 country is based to a great extent on chemical processes 
 originated or perfected by foreign chemists, Leblanc, Solvay, 
 and Castner, the coal-tar colour industry, founded on pioneer 
 work done in England, was unable to hold its own against 
 foreign competition. There is this possibly to be said in 
 explanation of the difference. The chemistry of the alkali 
 manufacture is extremely simple, and the difficulties which 
 had to be overcome, though serious enough, were mostly on 
 the engineering side ; the colour industry, on the contrary, 
 depends, not only hi its initial stages but throughout, on 
 persistent and organized scientific research, requiring the 
 encouragement and support of the manufacturers. The 
 institution which is associated with its birth the Royal 
 College of Chemistry was an exotic growth disconnected 
 from any university, and without permanent influence on 
 university teaching. Its director, Hofmann, was, at that 
 period, concerned with training scientific men rather than 
 manufacturing chemists, and no efforts were made to bridge 
 the gap between the laboratory and the factory. 
 
 The alkali industry presents a more pleasing history, 
 Joshua Ward, of Twickenham (1685-1761), first commer- 
 cially produced oil of vitriol in glass globes of forty to fifty 
 gallons capacity, and a very important advance was made 
 by Dr. John Roebuck, of Birmingham (1718-1794), who, in 
 1746, erected the first lead chambers. A name more directly 
 connected with the manufacture of alkali is that of Joseph 
 Christopher Gamble (1776-1884), who was trained up for 
 
W. E. Ayrton, Christopher Gamble 195 
 
 the Church, and while passing through his studies at Glasgow, 
 attended a course of chemistry under Dr. Cleghorn. He 
 became sufficiently interested to carry on privately chemical 
 experiments in his leisure time. After taking up his duties 
 as Presbyterian minister at Enniskillen, he saw hand-loom 
 weavers in his parish working the flax grown by farmers in 
 the neighbourhood, and prepared solutions of chlorine to 
 assist them in bleaching their linen. Finding that he could 
 utilize the residue left over from the production of chlorine in 
 producing Glauber salts, he decided to resign his ministry 
 and establish chemical works in Dublin. Here he manu- 
 factured bleaching powder, using the process patented by 
 Charles Tennant (1768-1838), the owner of the St. Rollox 
 Chemical Works, now merged in the United Alkali Company. 
 He further set up a plant to manufacture the necessary 
 sulphuric acid. Salt or brine, another indispensable ingre- 
 dient, had, however, to be obtained from a distance, and this 
 led him ultimately to leave Ireland, and build works at 
 St. Helens. There he was associated during ten years with 
 James Muspratt, and afterwards with the brothers Cross- 
 field, soap-boilers, of Warrington. The trouble arising from 
 the damage done to the surrounding country by the noxious 
 gases set free in the process of manufacture hampered the 
 work considerably, and Gamble was slow to adopt the proper 
 remedies. The enmity of his neighbours and ill-health 
 ultimately made him abandon his work altogether. 
 
 To appreciate the work done by the chemical manu- 
 facturer in Gamble's time, it must be remembered that they 
 had generally to manufacture all the appliances they required. 
 Earthenware pots of sufficient size had to be produced, and 
 Gamble, blowpipe in hand, made his own thermometers and 
 hydrometers. 
 
 " Alkali " is an Arabic word originally applied to the ashes 
 of plants, and subsequently to the products derived from 
 these ashes, consisting of carbonate of soda and carbonate 
 of potash. The properties of these substances are so similar 
 that at first they were not distinguished as separate bodies. 
 As chemistry advanced, their metallic bases, sodium and 
 potassium, were grouped together under the term " alkali 
 metals," but technically, when the alkali industry is referred 
 
 N 2 
 
196 Britain's Heritage of Science 
 
 to, it includes only the sodium compounds, and of these, 
 strictly speaking, only the hydrate and the carbonate ; 
 but the manufacture of sodium sulphate and of hydro- 
 chloric acid is inseparably connected with the same in- 
 dustry. The first successful process of obtaining carbonate 
 of sodium is due to Leblanc, a French chemist, and one of 
 the victims of the French Revolution. Leblanc was born in 
 1753, near Orleans. He was first trained in an apothecary's 
 shop, but proceeded to the study of medicine, and was 
 appointed surgeon to the Duke of Orleans. In 1775 the 
 French Academy of Sciences offered a prize for the best 
 practical process of producing soda from common salt. 
 There were several competitors, but none of them were 
 judged worthy of receiving the prize. Nevertheless, Leblanc 
 patented his process, and the Duke of Orleans supplied the 
 capital for establishing works on a manufacturing scale. 
 But his connexion with that nobleman proved to be his 
 undoing. The Duke was executed, and the works were con- 
 fiscated. Leblanc struggled on in dire poverty for thirteen 
 years, when his property was returned to him by the Emperor 
 Napoleon. But it was too late; he had no capital to start 
 afresh, took refuge in a workhouse, and died by his own 
 hand. 
 
 James Muspratt (1793-1886), who introduced the Leblanc 
 process into England, was born in Dublin, and as a boy was 
 apprenticed to a wholesale druggist; he quarrelled with his 
 master, and went to Spain to take part in the Peninsular 
 War. His great ambition was to obtain a commission in the 
 cavalry; in this he was unsuccessful, and, refusing to accept 
 the position in the infantry which was offered him, he 
 followed the army in the wake of the troops. He fell ill, 
 made his way to Lisbon, but could not find a steamer to 
 take him home. Ultimately he secured an appointment as 
 midshipman in the Navy, and though promoted to the rank 
 of second officer, could not adapt himself to the strict disci- 
 pline of the Navy. He deserted while the vessel lay in the 
 Mumbles roadstead, and returned to Dublin. With the 
 knowledge gained during his apprenticeship and a small 
 inheritance, Muspratt then began his career as a manu- 
 facturing chemist. He started by making hydrochloric acid 
 
James Muspratt 197 
 
 and prussiate of potash. This did not satisfy his ambitions, 
 and when, in the year 1823, the prohibitive salt tax was 
 greatly reduced, he determined to work the Leblanc process, 
 and crossed over to Liverpool in search of a suitable locality 
 to erect his works. Not being provided with sufficient capital 
 he continued during a few years the manufacture of prussiate 
 of potash, until in 1828 he joined partnership with Christopher 
 Gamble and together they erected the St. Helens works. 
 Separating again two years later, Muspratt took a new site 
 at Newton-le- Willows. The same trouble arose which, as 
 has already been mentioned, discouraged Gamble. Newton 
 was in the heart of an agricultural district, and the farmers 
 very naturally resented having their crops spoiled by the 
 fumes of hydrochloric acid. Muspratt's business was so 
 seriously interfered with by continuous litigation that he 
 abandoned his works in 1850; and yet, ever since 1835, he 
 might have got over his difficulties had he given a trial to 
 the coke tower condenser of William Gossage (1799-1877), 
 which had been brought to his notice by the inventor. In 
 these condensing towers, the hydrochloric acid, instead of being 
 allowed to escape, is collected, and forms a by-product of 
 considerable commercial value. Gossage's process enabled 
 the alkali industry to develop with great rapidity, so that in 
 the twenty years between 1852 and 1872, the annual pro- 
 duction of alkali rose from 26,000 to 94,000 tons. Moreover, 
 the invention allowed the Alkali Acts to be passed and 
 strictly enforced, to the great advantage of the country in 
 which the works were situated. 
 
 In the Leblanc process, sulphate of soda (salt cake) is 
 formed by the direct action of sulphuric acid on salt; the 
 sulphate is converted into the carbonate by bringing it into 
 intimate contact with limestone and coal, and heating the 
 mixture. In another method, which has to a great extent 
 replaced that of Leblanc, the salt is acted on by ammonium 
 bicarbonate, with the result that sodium bicarbonate and 
 chloride of ammonium are formed. The ammonium bicar- 
 bonate, which forms the basis of the reaction, is generated 
 by saturating a salt solution with the ammonia obtained in 
 the recovery of the plant, and forcing carbonic acid gas into 
 the liquid. The process was first invented by G. Dyer and 
 
198 Britain's Heritage of Science 
 
 J. Hemming in 1838, and worked on a small scale in White- 
 chapel. Muspratt also had given it a trial at Newton, but 
 abandoned it again. After protracted investigations, the 
 Belgian chemist, Ernest Solvay, overcame the main manu- 
 facturing difficulties, and took out a patent in 1872. In the 
 meantime, Ludwig Mond (1839-1909) had settled in England 
 at the age of 23, and had gained practical experience with the 
 Leblanc process while occupied in some chemical works at 
 Widnes. Recognizing the possibilities of the ammonia-soda 
 process, he obtained a licence from Solvay, and in partnership 
 with Sir John Brunner, founded in 1873 the great chemical 
 works near North wieh. Further difficulties were experienced, 
 but these were gradually overcome, mainly by improved 
 devices for recovering the ammonia, on which the commercial 
 success of the process largely depends. 
 
 A third method of making alkalies became possible when 
 the introduction of dynamo-machines provided an easy 
 means of obtaining strong electric currents. Various electro- 
 lytic processes were then devised and patented. In the 
 Castner-KeUner method, used extensively in this country, 
 the kathode of the electrolytic trough is formed by mer- 
 cury, and the sodium is transferred by the current from the 
 solution to the mercury with which it amalgamates; by a 
 self-acting arrangement the amalgam is removed before it 
 becomes strong enough to act on the water. That action is 
 ultimately allowed to take place in another vessel, where a 
 solution of caustic soda is formed. 
 
 Among the chemical engineers of the alkali trade, Henry 
 Deacon (1822-1876) and Walter Weldon (1832-1885) also 
 hold distinguished places. They both successfully invented 
 independent and quite different processes for the manu- 
 facture of chlorine, which are still in use, though partly super- 
 seded by electrolytic methods. An important improvement 
 in the manufacture of sulphuric acid was made by J. Glover, 
 who, in 1866, introduced the important de-nitrating tower. 
 
 In the early forties of last century a determined effort 
 to promote chemical research was made in London. With 
 the support of Faraday and Brande, it was at first intended 
 to attach the necessary laboratories to the Royal Institution, 
 but on closer consideration the available space was found to 
 
L. Mond, W. Weldon, W. Perkin 199 
 
 be insufficient, and it was decided to establish a separate 
 institution, under the name of the Royal College of Chemistry. 
 The proposal matured largely through the influence of the 
 Prince Consort and the Queen's physician, Sir James Clark. 
 Temporary accommodation was found in George Street, 
 Hanover Square, until a larger building in Oxford Street 
 could be adapted. Justus Liebig, whose authority in questions 
 of chemistry was paramount at the time, was asked to 
 recommend a suitable director for the new institution, and 
 ultimately August Wilhelm Hofmann, a young assistant at 
 the University of Bonn, accepted the appointment. The 
 school was opened in 1845, and Hofmann threw himself 
 so heartily into the work that it soon attracted a large 
 number of promising pupils. It is, indeed, remarkable to 
 find among the early students of the Royal College so many 
 men who subsequently rose to eminence ; we note among them 
 Sir William Crookes, Sir Frederick Abel, Herbert Macleod, and 
 Sir William Perkin. The College continued until 1864, when 
 it was absorbed into the School of Mines. Perkin (1838- 
 1907) was fifteen years old when he came under the influence 
 of Hofmann. After passing through the ordinary training, 
 he was appointed honorary assistant to his teacher, and 
 henceforward devoted himself to research work. Hofmann's 
 own investigations at the time dealt with the organic 
 compounds derived from coal-tar; it was a purely scientific 
 research, undertaken without reference to any industrial 
 applications. Perkin was set to work on anthracite, and, 
 though interesting results were obtained, the chief value of 
 his early work was the acquisition of the experience which 
 he was to turn to such good account later. 
 
 The artificial production, or synthesis, as it is techni- 
 cally called, of natural organic compounds was then in its 
 infancy, and it was generally supposed that if, by abstracting 
 or adding oxygen or water, a compound could be formed 
 having the same number of oxygen, carbon, and hydrogen 
 atoms as the desired substance, the synthesis was likely 
 to be successful. Hofmann had suggested the artificial pro- 
 duction of quinine as a useful subject for research. The 
 problem attracted Perkin, and as he was at the time busy 
 with other work for his Professor, he decided to pursue the 
 
200 Britain's Heritage of Science 
 
 investigation in the private laboratory he had established at 
 home. Following the deceptive guidance of the accepted 
 doctrine, he tried to synthesize quinine by treating one of the 
 coal-tar products with bichromate of potassium, but only 
 obtained a dirty reddish-brown precipitate. Maxwell once 
 said that he never stopped a man from carrying out an 
 unpromising research, because, though he would almost 
 certainly not find what he expected, he might find some- 
 thing else. Perkin had found something else, and showed 
 the proper researching instinct by accepting the hint. 
 Replacing the more complicated compound which he had 
 used by another coal-tar product, " aniline," he obtained 
 an almost black precipitate, which, on further examination, 
 proved to have dyeing properties. This led to the discovery 
 of aniline purple, later called " mauve," the first of the arti- 
 ficial colours. Perkin saw the possibility of a useful application 
 before him, and sent a sample of the dye to Messrs. Puller, 
 of Perth, who, recognizing its value, replied : "If your 
 discovery does not make the process too expensive, it is 
 decidedly one of the most valuable that has come out for a 
 long time." 
 
 Perkin resigned his position at the Royal College, and 
 with the assistance of his father built a factory at Greenford 
 Green, near Sudbury. To supply the dye cheaply, an econo- 
 mical method of preparing aniline had to be worked out. 
 This was first accomplished by the French chemist Bechamp, 
 whose share in the work was always fully recognized by 
 Perkin. The new dye-stuff was brought into the market 
 towards the end of 1857, and the demand for it increased 
 rapidly. 
 
 The aniline dyes are products which do not occur in nature. 
 A fresh departure was made in 1868, when Graebe and Lieber- 
 mann succeeded in the artificial formation of alizarin, the 
 dyeing principle of the madder plant. The method used was, 
 however, too costly to hold out any hope of competing 
 successfully with the product derived directly from the 
 plant, which was grown extensively in the south of France. 
 Within a year Perkin invented another process that promised 
 and attained commercial success. In the meantime, Graebe 
 and Liebermann had independently been led to the same 
 
W. Perkin, E, C. Nicholson 201 
 
 method. The Greenford factory, however, was ready to 
 start work at once, and until 1873 there was practically no 
 competition with the coal-tar dyes produced in this country. 
 In his report on the exhibition of 1862, Hofmann 
 wrote : 
 
 " England will, beyond question, at no distant date 
 become, herself, the greatest colour- producing country 
 in the world; nay, by the strangest of revolutions, she 
 may, ere long, send her coal-derived blues to indigo- 
 growing India; her tar-distilled crimson to cochineal- 
 producing Mexico, and her fossil substitutes of quercitron 
 and safflower to China, Japan and other countries, whence 
 these articles are now derived." 
 
 This is not the place to discuss the causes which have 
 falsified Hofmann's prophecy. The " near future " of his 
 prediction is passed, but another future lies ahead of us. 
 
 Perkin also carried on investigations of a great value in 
 pure science, even during the busy time of his industrial 
 enterprises. He sold his factory in 1874, devoting himself to 
 the time of his death to a life of scientific research. 
 
 Among the pupils working in the laboratories at George 
 Street we find Edward Chambers Nicholson (1827-1890), 
 of whom Hofmann, at a later period, wrote : " He united 
 the genius of the manufacturer with the habits of a scientific 
 investigator." In his first research he determined the con- 
 stitution of strychnine. After leaving the Royal College, 
 he became associated with Messrs. Maule and Simpson in 
 the preparation of various chemical products, turning his 
 attention ultimately to colouring matters. His name is 
 chiefly connected with the manufacture of " regina purple " 
 and " Nicholson's blue." 
 
 A worthy successor of Perkin and Nicholson might, 
 with proper opportunities, have been found in Raphael 
 Meldola (1849-1915), who, between 1879 and 1885, made 
 important discoveries of new dye-stuffs. But though he 
 was during eight years connected with a firm manufacturing 
 colours, he received little encouragement from his employers, 
 and his work bore no immediate fruit. Meldola always held 
 the opinion that the decline of the colour industry in 
 England was not due, as is commonly asserted, to the 
 
202 Britain's Heritage of Science 
 
 defects of our patent laws, or other restrictions imposed by 
 the legislature of the country, but to the neglect of continued 
 scientific research within the factory. 
 
 Sir Frederick Abel (1827-1902) has been mentioned as 
 one of the students of the Royal College of Chemistry. His 
 subsequent work, carried on while he occupied the position 
 of Professor of Chemistry at the Koyal Military Academy 
 and Chemical Advisor to the War Department, dealt mainly 
 with the manufacture of explosives. Through his efforts 
 guncotton could be made and handled without danger, and 
 cordite is the joint invention of himself and Sir James Dewar. 
 He also designed the apparatus, legalized in 1879, for the 
 determination of the flash point of petroleum. 
 
 The name of Lyon Playfair (1819-1898) deserves to be 
 remembered as one who actively encouraged research through- 
 out his life, and exercised a considerable amount of influence 
 in promoting scientific enterprises. He was born in India, 
 educated at St. Andrews, and subsequently studied medicine 
 at Glasgow. Attracted towards chemistry by the teaching 
 of Thomas Graham, he went to study the subject under 
 Liebig at Giessen. For two years he managed the chemical 
 department of some print works in Clitheroe. Though he 
 subsequently held for a time the Professorship of Chemistry 
 at the Royal Institution in Manchester, at the School of 
 Mines in London and at the University of Edinburgh, it 
 is neither as a teacher nor investigator, but rather as a con- 
 sistent upholder of scientific principles, that he has left 
 his mark. He had a considerable share in the organization 
 of the Great Exhibition of 1851, and in the foundation of the 
 Department of Science and Art. In 1844 he sat on the Royal 
 Commission for the examination of the sanitary conditions 
 of large towns and public districts, and maintained through- 
 out his life a great interest in that subject. He served on 
 many other Royal Commissions. In 1868, Playfair was 
 returned as the first representative in Parliament of the 
 Universities of St. Andrews, and in 1885 was elected member 
 for the southern division of Leeds. He held office as Post- 
 master-General, and later as Vice-President of the Council 
 of Education. The honour of a peerage was conferred upon 
 him in 1892. 
 
203 
 
 CHAPTER VII 
 
 SCIENTIFIC INSTITUTIONS 
 
 GREAT ideas spring from individual brains, but a com - 
 bination of brains working through scientific organi- 
 zations may perform important functions in stimulating 
 research, accumulating material or carrying out experiments 
 which are beyond the means of one man. An organization 
 is generally called into existence for a particular purpose, 
 but to be permanently successful its constitution must be 
 sufficiently elastic to allow a change of methods or even of 
 aims when the original need has ceased to be urgent or 
 fresh requirements have appeared. This elasticity has, 
 indeed, been a distinguishing feature of our own scientific 
 institutions, which have generally been able to adapt them- 
 selves to the changing circumstances of the time. 
 
 The origin of the Royal Society of London may be traced 
 to weekly meetings of men engaged in philosophical enquiries, 
 who came together to discuss questions of scientific interest. 
 These meetings began about 1645. A few years later 
 some of the members moved to Oxford, and independently 
 met in that University. The London meetings were inter- 
 rupted in 1658, owing to political troubles ; but, after the 
 return of Charles II., it was decided to establish a more 
 formal organization. A society was then formed which 
 met at Gresham College; the Bang became interested in 
 its work, with the result that it obtained a charter in 1662, 
 with the title of " The Royal Society." Further privileges 
 were given in a second charter, 1 which was granted and 
 signed on May 13th, 1663, and the regular activity of the 
 
 1 The second charter confers the present title : " The Royal 
 Society of London," and adds its purpose : " for promoting Natural 
 Knowledge (pro scientia naturali promovenda)." 
 
204 Britain's Heritage of Science 
 
 Society begins with that date. Twenty-one members were 
 named in the charter to constitute the first Council. Ninety- 
 four additional Fellows were selected by that body shortly 
 afterwards, of whom comparatively few are known by their 
 scientific work. Men of general culture sympathetic to the 
 revival of learning, statesmen, and even poets, were freely 
 included. It was not only science that benefited by this 
 liberal interpretation of the functions of the Society, for, 
 quoting Professor Oliver Elton, 1 " The activities of the 
 newly founded Royal Society told directly upon literature, 
 and counted powerfully in the organization of a clear uniform 
 prose the close, naked, natural way of speaking, which the 
 historian of the Society, Sprat, cites as part of its programme." 
 The meetings of the Royal Society, at first, served mainly to 
 promote friendly intercourse between its Fellows; experi- 
 ments were shown by a specially appointed " curator," 
 subjects were proposed for investigation, and sometimes 
 Fellows were asked to undertake particular researches. 
 The publication of results did not originally form any 
 prominent part of the work, and only gradually gained 
 importance. 
 
 The preceding pages have been full of examples illus- 
 trating the discoveries made by Fellows of the Society; 
 we are here concerned with the influence which the Society 
 exerted in its corporate capacity. From the beginning it 
 acted as adviser to the Government in scientific matters, 
 and interested itself in the general welfare of the country. 
 During the first year of its existence, the King expressed the 
 wish that " no patent should be passed for any physical or 
 mechanical invention, until examined by the Society." In 
 the same year a report was presented and approved by the 
 Society " to plant potatoes, and to persuade their friends 
 to do the same, in order to alleviate the distress that would 
 accompany a scarcity of food." In 1732 it took measures 
 to promote the practice of inoculation. In 1750, its assistance 
 was invoked for the purpose of improving the distressing 
 state of ventilation of prisons, which was the cause of the 
 high death rate due to "jail fever." Sir John Pringle and 
 
 1 ** Encyclopaedia Britannica," Article on English Literature. 
 
The Royal Society 205 
 
 Dr. Hales on behalf of the Society recommended the use 
 of ventilators, and these being introduced/ the number of 
 deaths in Newgate was reduced from seven or eight a week 
 to about two in a month. 
 
 In March 1769, the Dean and Chapter of St. Paul's 
 requested the Society's advice as to the most effectual 
 method of fixing electrical conductors on the cathedral to 
 protect it against the dangers of lightning. A committee was 
 appointed, including John Canton and Benjamin Franklin, 
 and reported on the subject; among the recommendations 
 adopted by the authorities was that of using the waterpipes 
 to serve as conductors between the roof and the ground. 
 Three years later a similar request was received from the 
 Government to protect powder magazines, and in 1820 the 
 Society advised the Admiralty on a system of lightning 
 conductors for use on ships which had been proposed by 
 Sir Snow Harris. In May 1824 the Council of the Society 
 appointed a Committee " for the improvement of glass for 
 optical purposes." Valuable results were obtained with glasses 
 prepared under the direction of Faraday, and examined by 
 John Dollond and Sir John Herschel. Unfortunately, owing 
 to the important electrical experiments which then engaged 
 the attention of Faraday, the Committee did not proceed 
 with the further proposal to organize the manufacture of 
 optical glass for general sale. 
 
 The indefatigable first curator of the Society had, a 
 few years after its foundation, formed the nucleus of a 
 collection of " natural rarities," and this gradually grew 
 into an important collection or " repository," enriched by 
 contributions from distant countries. Ultimately, the greater 
 part of it was handed to the British Museum, but the follow- 
 ing letter, addressed by three Fellows of the Society to the 
 Hudson Bay Company in 1777, shows that the specimens 
 presented were examined with a view to their general 
 utility : 
 
 " Having endeavoured to find out whether some of 
 the natural productions which you have been so obliging 
 as to present to the Royal Society may not furnish 
 materials for our manufactures, we take the liberty of 
 stating to you the result of our enquiry. We have put some 
 
206 Britain's Heritage of Science 
 
 parts of one of the buffalo's hides into the hands of a tanner, 
 and are informed, both by a very experienced leather- 
 dresser and bookbinder, that it seems to be as good a 
 material as the skin of the Russian buffalo for book- 
 binding. If these skins, therefore, can be procured in any 
 quantity, the importation may answer well to the Com- 
 pany, and no further preparations of the hides will be 
 necessary in Hudson's Bay, than to dry them properly 
 with the hair OH, and to take care that the sea water does 
 not injure them on the passage. It is supposed that each 
 skin brought in this way to England may be worth about 
 four shillings. We also beg leave to present to the Com- 
 pany, in the name of the Society, a pair of stockings made 
 here from the hair of one of the buffalo's hides, which 
 hung near the neck, as also a hat ; but it may be proper to 
 inform you, that the greatest part of the materials used 
 in the latter is rabbit's hair, as that of the buffalo cannot 
 be worked into a proper consistence for this purpose, 
 without a mixture of some other hah 1 . As you have pre- 
 sented to the Society likewise a specimen of a wild swan, 
 we have put the skin into the hands of an importer, and 
 we thall, perhaps, surprise you when we inform you, that 
 if it had been in a state to be properly dressed, it would 
 have been worth at least a guinea and a half; so scarce 
 is this commodity at present, and so great is the demand 
 for powder-puffs, the best sort of which can only be made 
 from swansdown. We have stated, however, that the 
 akin sent from Hudson's Bay was absolutely spoilt by 
 not being properly prepared, though we are informed that 
 nothing further is necessary than the following simple 
 process. All the feathers must be pulled off as soon as 
 the swan is killed, leaving only the down on; after this 
 the skin must be cut off along the back, and stripped off 
 the body, then take all the fat away, and turning the 
 skin inside out, let it dry. As swan-skins, therefore, are 
 so valuable an article of commerce at present, and there 
 is a probability of procuring many of them from Hudson's 
 Bay, it may be worth while for the Company to purchase 
 one of them, for the more fully instructing their servants 
 in what state they should be sent over." 
 
The Royal Society 207 
 
 Many scientific expeditions were promoted and organized 
 by the Royal Society. Through its efforts the Govern- 
 ment was induced to send out well-equipped expeditions 
 to observe the transits of Venus in 1761 and 1769, promi- 
 nence being given in their representation not only to the 
 importance of the occurrence, but to the circumstance that 
 the first and so far only observation of this rare event was 
 made by the Lancashire curate Horrocks, 
 
 In 1773 representations were made to the Earl of Sand- 
 wich, first Lord of the Admiralty, strongly urging the desira- 
 bility of organizing an Arctic Expedition, partly on the ground 
 that this might result in the cfiscovery of a passage to the 
 East Indies by or near the North Pole. The wishes of the 
 Society were complied with ; two ships, the Racehorse and 
 the Carcass, were fitted out, and an astronomer accompanied 
 the expedition, with instructions drawn up by a Committee 
 of the Royal Society. The ships returned without having 
 achieved much ; but in two later expeditions, leaving Eng- 
 land early in 1818 and in 1819, most valuable scientific 
 results were obtained by Colonel (afterwards General) 
 Sabine. 
 
 In 1784 the Council of the Royal Society petitioned 
 George III. to place funds at the disposal of the Society to 
 commence a geodetical survey, with a view to establishing a 
 trigonometrical connexion between the observatories of Paris 
 and Greenwich. The King gave his consent, and Major 
 General Roy was appointed to carry out the undertaking. 
 This was the origin of the British Survey Office. Its work 
 was hampered, at the outset, by the unsatisfactory nature 
 of the standards of length. Already, in 1742, the Royal 
 Society and the French Academy had instituted comparisons 
 between the standards of measures and weights of the two 
 countries which led to some improvement, and in 1758 
 a committee of the House of Commons enquired into the 
 subject; but no legislative action was taken until 1824. 
 The question presented considerable difficulties, because 
 the two original standards, one dating back to King 
 Henry VII., kept at the Tower, and the other made during 
 the reign of Queen Elizabeth, kept at the Exchequer, were 
 of the rudest description, and did not agree with each other. 
 
208 Britain's Heritage of Science 
 
 Francis Baily in 1836, referring to the latter, writes : "A 
 common kitchen poker, filed at the ends by the most bungling 
 workman, would make as good a standard. It has been 
 broken asunder and the two pieces have been dovetailed 
 together, but so badly that the joint is nearly as loose as that 
 of a pair of tongs." In 1816 the Royal Society had received 
 from the Secretary of State a request for assistance in 
 ascertaining the length of a pendulum vibrating seconds of 
 time at different stations of the Trigonometrical Survey. 
 This brought the question of standards into prominence, 
 and led to much valuable work being done ; but in the final 
 construction of the present standards the Royal Astrono- 
 mical Society took the lead, under the energetic superin- 
 tendence of Francis Baily. 
 
 Greenwich Observatory, established by Charles II., was, 
 from its foundation, closely connected with the Royal Society. 
 In 1710 Queen Anne appointed its President and such other 
 Fellows as he might nominate to be visitors of the Obser- 
 vatory. For some time the Society exercised a real control 
 over the work, receiving regular reports, making recommen- 
 dations, and collecting the results for publication. At 
 present the Royal Astronomical Society is associated with 
 the Royal Society in nominating the members of the Board 
 of Visitors. The important work carried out at Greenwich 
 has been frequently referred to in these pages; it is recog- 
 nized as the leading observatory of the world, and fixes the 
 time used in all civilized countries. 
 
 The study of Meteorology owes much to the Royal Society, 
 which in 1725 provided at its own expense a number of baro 
 meters and thermometers to be used by its correspondents 
 in different parts of the world. In 1773 the Council organized, 
 under the superintendence of Henry Cavendish, regular 
 meteorological observations in its own building, including the 
 measurement of temperature, pressure, moisture, and wind 
 velocity. These observations were conducted, and published 
 annually in the Philosophical Transactions, for nearly sixty 
 years. They were discontinued because the situation of the 
 building was not considered suitable, and regular observa- 
 tions had been established at the Royal Observatory. A 
 meteorological department of the Board of Trade was super- 
 
Greenwich Observatory, Meteorology 209 
 
 seded in 1867 by a Meteorological Committee of the Royal 
 Society, which was entrusted with the whole of the meteoro- 
 logical work of the country. This was followed, in 1877, by 
 the Meteorological Council, consisting of the President and 
 four members nominated by the Royal Society, together with 
 the Hydrographer of the Navy. Since 1905 a special 
 Committee of H.M. Treasury, containing two representatives 
 of the Royal Society, is entrusted with the meteorological 
 organization of the country. 
 
 In 1842 regular magnetical as well as meteorological 
 observations were instituted at Kew Observatory, built 
 in 1769 by King George III. for the purpose of observing 
 the transit of Venus which occurred in that year. It came 
 for a time under the direction of the British Association, 
 but was handed over to the Royal Society in 1881 ; it 
 passed to the National Physical Laboratory in 1905, and is 
 now under the control of the Meteorological Committee. 
 The Royal Society continues, however, to administer a Trust 
 Fund of 10,000 conveyed to it by John Peter Gassiot, for 
 the purpose of providing for magnetical and meteorological 
 observations, which are being taken at Kew and Eskdale- 
 muir. The directors of Kew Observatory included many 
 distinguished men; among them Francis Ronalds, inventor 
 of the first electric system of telegraphy, who designed and 
 introduced the self-registering meteorological instruments, 
 and Balfour Stewart, whose work has been mentioned in 
 Chapter V. 
 
 It was chiefly through the influence of General Sabine 
 that the Royal Society was, during many years, the chief 
 promoter of the study of Terrestrial Magnetism. Observa- 
 tories all over the world were, directly and indirectly, organ- 
 ized by that powerful and energetic personality. The East 
 India Company gave valuable help, and when the Royal 
 Society in the year 1840 approached the Russian Government, 
 a speedy reply was received through the Foreign Office that, 
 in consequence of the representations made by the Society, 
 Russia had established ten magnetical observatories in her 
 Empire, and was willing to provide the funds for a further 
 one to be erected at Pekin. 
 
 The National Physical Laboratory was established in 
 
 
 
210 Britain's Heritage of Science 
 
 1899, and placed under the control of the Royal Society. 
 Its primary object is to provide proper standards of measure- 
 ment for all branches of science, to test materials, to verify 
 the indications of instruments and to determine physical 
 constants. To serve these purposes, it has to be provided 
 with means for carrying out researches on a large scale, more 
 especially on problems connected with the industrial appli- 
 cations of science. The Laboratory is administered by an 
 Executive Committee, on which six of the more important 
 technical societies are represented. From small beginnings 
 the Laboratory has grown, under the directorship of Sir 
 Richard Glazebrook, with quite remarkable rapidity, and at 
 present its total annual income amounts to 50,000, of which 
 nearly two-thirds is received for work done for private firms 
 or Government departments. 
 
 With foreign academies the Royal Society has always 
 maintained most friendly relationships ; intercourse between 
 scientific men of different countries was, indeed, one of its 
 primary objects. In May 1661, before the incorporation of 
 the Society by Royal Charter, one of its members gave an 
 account of the proceedings at a meeting of French scientists 
 who formed the nucleus of the future French Academy of 
 Science, and in July of the same year a letter was addressed 
 to them requesting the interchange of scientific informa- 
 tion. In a communication sent to the Council of the 
 Royal Society by Christian Huygens during the same month, 
 after referring to his observations on Saturn, the author writes 
 that the members of the French body were " excited to 
 emulation of the Society of London, and proposed applying 
 themselves to philosophical experiments;" and adds that 
 this is " a good effect produced by your example." The 
 " Academie des Sciences " began to meet regularly in 1666, 
 but was constituted finally only in the year 1699. The 
 intimate relationship between the two scientific societies was 
 illustrated in a striking manner when Sir Humphry Davy 
 visited Paris while France and England were at war with 
 each other. He was received with the highest honours, 
 awarded a gold medal (p. 115), and elected a foreign member. 
 In the early days of the Society, Mr. Henry Howard 
 (afterwards Duke of Norfolk) interested himself in securing 
 
The Royal Society 211 
 
 correspondents in different parts of Europe, with a view to 
 adding specimens of interest to its collection, and obtain- 
 ing information of value to the industries of the country. 
 " Methinks," he writes, " it were worth our knowledge 
 whether there are not now some persons in Italy that know 
 the old Roman way of plaistering, and the art of tempering 
 tools to cut porphyry, the hardest of marbles " ; and, again : 
 " I am lately informed that there is a mineral salt plentifully 
 to be found in the mines of Calabria, which has this particu- 
 larity, that, being cast into the fire, cracks not, nor breaks 
 in pieces. A specimen of that also would be acceptable." 1 
 
 The first communication from the then recently estab- 
 lished Academy of Sciences at Petrograd was received at 
 the last meeting over which Sir Isaac Newton presided. 
 After quoting the desire of the Czar to follow the English 
 example in encouraging and cultivating science, the letter 
 concludes with the assurance that the Russian Academicians 
 " are the more inclined to make their addresses to, and 
 desire most to have the approbation of, the Royal Society, 
 as being the first of its kind, and that which gave rise to all 
 the rest." 
 
 The Royal Society has always encouraged the formation 
 of scientific bodies of similar aims in other parts of the United 
 Kingdom. In 1684 such a society was established at Dublin, 
 with full encouragement of the authorities of the Royal 
 Society, offered also to a similar effort made at Edinburgh 
 in 1705. In 1731 a separate society for the improvement of 
 medical knowledge was instituted in the latter city, but was 
 re-modelled so as to include other subjects in 1739. It was this 
 body which, under the name of " Royal Society of Edin- 
 burgh," received its charter in 1783. The great work carried 
 out by the scientific men of Scotland and Ireland, described 
 in the preceding pages, is a sufficient indication of the influence 
 exerted by the Royal Societies of Edinburgh and Dublin, 
 which as also the Irish Academy of Sciences (founded in 
 1782) have always co-operated with the London Society in 
 their common aims. The Royal Society of Arts was founded 
 in 1753, for the promotion of Arts, Manufactures, and 
 
 1 Weld's "History of the Royal Society,*' VoL I., p. 189. 
 
 O 2 
 
212 Britain's Heritage of Science 
 
 Commerce, and the success with which it has worked to 
 attain its objects needs no comment. 
 
 When science became more specialized, the need for 
 separate societies dealing with the more technical portions 
 of each subject began to grow. These societies now take an 
 important share in the promotion of scientific researches. 
 The Linnaean Society was founded in 1788, the Geological 
 Society in 1807, the Royal Astronomical Society in 1820, 
 and the Chemical Society in 1841. 
 
 What strikes the foreign visitor most when he enquires 
 into the working of British scientific institutions is that the 
 Royal Society receives no subvention from the Government. 
 While in all foreign academies, the members receive an annual 
 sum from the State, in England they pay both an entrance 
 fee and regular subscriptions. The great French naturalist, 
 Cuvier, has some interesting remarks on the subject. 1 The 
 Royal Society, the oldest of the scientific academies, is, he 
 says, " sans contredit 1'une des premieres par les decouvertes 
 de ses membres," and he attributes this to the fact that, as 
 it depends for its subsistence on the contributions of its own 
 members, the number of Fellows must necessarily be large. 
 The more numerous a body, he argues, the smaller is the 
 number of those who control its administration ; hence the 
 Council of the Royal Society, in whom the administration 
 is vested, is a small body with great powers, and can exert 
 a stronger influence on the progress of science than con- 
 tinental academies can do. 
 
 So far from the Royal Society having ever received sub- 
 ventions by the Government for general purposes, its Council 
 resolved unanimously in 1798 to pay into the Bank of England 
 a sum of 500 as a voluntary contribution towards the 
 defence of the country. Up to that time, the whole expendi- 
 ture of the Society was paid out of the entrance fees and 
 subscriptions of the Fellows, the only legacy which had 
 been received being a sum of 500 from Lord Stanhope, 
 paid over in 1786. During the last century the financial 
 resources of the Society have, however, been increased by a 
 number of valuable endowments. 
 
 de 1'Institut," 1826, p. 219. 
 
Thomas Young 
 
The Royal Institution 213 
 
 The Society is now entrusted with the administration 
 of certain funds devoted by the Government to definite 
 purposes, such as grants towards scientific researches, and 
 the publication of scientific literature. It has been given 
 free use of its apartments, first in Gresham College, later in 
 Somerset House, and now in Burlington House. 
 
 There is no building in the world associated with so 
 many classical and revolutionizing researches as that in 
 which the Royal Institution is housed. The idea which led 
 to its foundation is generally ascribed to Count Rumf ord ; 
 the earliest document referring to the matter is an account 
 of a meeting held at the house of Sir Joseph Banks, the 
 President of the Royal Society, at which Count Rumf ord and 
 other Fellows of the Royal Society were present. The title 
 and purposes of the institution were then defined to be " for 
 diffusing the knowledge, and facilitating the general intro- 
 duction, of useful mechanical inventions and improvements ; 
 and for teaching, by courses of philosophical lectures and 
 experiments, the applications of science to the common 
 purposes of life." 
 
 The idea of research grew up in the time of Young and 
 Davy, though Count Rumford must have had it in mind 
 when through his influence the latter was appointed as first 
 Professor of Chemistry. Much has already been said about 
 the work of these two great philosophers, as well as that of 
 Faraday, who succeeded Davy. Their successors worthily 
 upheld the traditions of the Chairs. John Tyndall (1820- 
 1893) was appointed Professor of Natural Philosophy in 
 1854, and succeeded Faraday as superintendent of the labora- 
 tories in 1866. He spent a useful life in scientific research, 
 but will be remembered mainly as an advocate of scientific 
 principles and popularizer of science. His books have 
 inspired many young men to the pursuit of science, and the 
 one on " Heat as a Mode of Motion " still deserves to be 
 read as a clear exposition of the fundamental principles of 
 heat. 
 
 Sir James Dewar, who now occupies the Chair held by 
 Davy and Faraday, has made his name famous through his 
 researches on the liquefaction of gases. He was the first to 
 liquefy air on a large scale, and subsequently following up 
 
214 Britain's Heritage of Science 
 
 some earlier work of Worblewsky, he succeeded in not only 
 liquefying, but also solidifying, hydrogen. By using liquid 
 hydrogen, he was finally able to condense helium. He made 
 extensive investigations on the properties of bodies at low 
 temperatures, and his determination of the specific heats of 
 elements as they approach the absolute zero of temperature 
 has thrown quite a new light on the laws which up till then 
 were believed to connect specific heat and atomic weight. 
 Referring to his discovery of the absorptive properties of 
 charcoal, we may quote the words of the President of the 
 Royal Society in awarding him the Copley Medal in 1916 : 
 " Many of the most interesting and important investigations 
 made in Physics in recent years would have been impossible 
 but for his invention of the method of obtaining very high 
 vacua by the use of charcoal immersed in liquid air or 
 hydrogen." 
 
 A few words may be said in conclusion on the activities 
 of the British Association, which held its first meeting 
 at York in 1831. Its object was mainly the same as that 
 which in the seventeenth century originated the meetings 
 which ultimately led to the foundation of the Royal Society. 
 British science in the nineteenth century could no longer be 
 confined to the metropolis, and the provision of a more 
 intimate and personal scientific intercourse between men 
 residing in different parts of the country became desirable. 
 To the outside world the meetings of the British Association 
 appear to be confined to annual discussions on a variety of 
 subjects; but the main work of the Association is carried 
 on throughout the year, and it can claim to have originated 
 scientific enterprises of the highest value and importance. 
 The introduction of scientific electrical units is the result of 
 work initiated by the British Association, and in great part 
 carried out by one of its Committees. Under the protection 
 and with the financial support of the same body, John Mime 
 was enabled to establish his international organization for the 
 observation of earth tremors, and the need for the establish- 
 ment of a National Physical Laboratory was first advocated 
 by Sir Oliver Lodge at one of the meetings of the British 
 Association. 
 
 The history of the British Association forms a good 
 
The British Association 215 
 
 example of the advantages of a liberal and flexible constitu- 
 tion, which allows it to adjust its procedure and conditions 
 to the ever-changing and increasing requirements of science. 
 
 In concluding that part of Britain's heritage which deals 
 with Physical Science, we may express the hope that the 
 country will deserve, with increasing justification, the praise 
 bestowed upon it by Biot 1 : " Souhaiter une chose utile aux 
 sciences c'etait avoir d'avance Tassentiment des savants 
 d'Angleterre et 1'approbation du gouvernement de ce pays 
 eclaire." 
 
 1 Cl M&noires de PInstitut de France," 1818. 
 
216 Britain's Heritage of Science 
 
 CHAPTER VIII 
 BIOLOGICAL SCIENCE IN THE MIDDLE AGES 
 
 npHROUGHOUT the Middle Ages natural science was a 
 -I- study of the written word of ancient writers, whose 
 authority went unquestioned. Processes of observation or 
 experiment were barely known. To this mediaeval tradition 
 the age of the Tudors, in its attitude to scientific study, was 
 to a large extent loyal. Authority was still final and definite. 
 What Galen and Hippocrates, Aristotle and Pliny had written 
 was subject-matter for dispute, for discussion, for argument, 
 but not for direct investigation. In the same way the new 
 light derived from the Arabs, which spread through the 
 learned world at the latter end of the twelfth and at the 
 beginning of the thirteenth centuries, was treated as a 
 matter for dialectics by those who set the written word 
 before actual observation or experiment in Nature. 
 
 Let us consider the books in English at the disposal of 
 an average man in the latter half of the sixteenth century. 
 Through mediaeval times had drifted a certain " corpus " 
 of moralized natural history known as the " Physiologus," 
 which was in essence a Bestiarium. It took various forms, 
 and was read throughout Europe and the Near East. This 
 " Physiologus " was primarily religious in its aim, but dealt 
 not only with the animals mentioned in the Bible but with 
 other and often mythical monsters. Scientifically the 
 zoology of the " Physiologus " was of the poorest; in fact, 
 the study of zoology was at its worst during the Middle 
 Ages; it had fallen far lower than in classical days. The 
 " Physiologus " had its origin in Alexandria in early Christian 
 times, and was translated into many tongues, including 
 Coptic. It was sometimes fathered upon Ambrose, but is 
 older than his day. 
 
 During the eleventh century a certain " Episcopus 
 
Bartholomaeus Anglicus 217 
 
 incertus," one Theobaldus, made a metrical version of the 
 descriptions of twelve of the animals dealt with in this little 
 volume. This was published under the name " Physiologus 
 Theobaldi Episcopi de naturis duodecim animalium," the 
 earliest printed edition being that issued at Delft in 1487. 
 Numerous editions were published in many countries for the 
 following century or two, but the contents of the volume 
 were in a state of flux, additions and omissions appearing 
 in many of the issues. 
 
 But the chief book on natural history in the Middle Ages 
 was an encyclopaedia entitled " Liber de Proprietatibus 
 Rerum," compiled by the English Franciscan, Bartholomew 
 often called Bartholomaeus Anglicus, who probably wrote 
 some time about 1250, certainly before 1267, and in all 
 probability before 1260. Both before and after the invention 
 of printing this work had a wide circulation. The " Liber " 
 was translated into French by the order of Charles V., into 
 Spanish in 1372, then into Dutch, and in 1397 into English. 
 It was also the first book printed on paper which had been 
 made in England. This book is believed to have been the 
 source of much of Shakespeare's knowledge of natural history. 
 In 1582 the Rev. Stephen Bateman, D.D., domestic chaplain 
 to Bishop Parker, re-issued the English translation made by 
 John of Trevisa which had been printed in 1494 by Wynkyn 
 de Worde at Westminster. The book was entitled : 
 
 " Bateman uppon Bartholome. His Booke De Pro- 
 prietatibus Rerum : newly corrected, enlarged, and 
 amended, with such Additions as are requisite, unto 
 every severall Booke. Taken foorth of the most approved 
 Authors, the like heretofore not translated in English. 
 Profitable for all Estates, as well for the benefite of the 
 Mind of the Bodie." Lond. 1582, fol. Dedicated to 
 Lord Hunsdon. 
 
 Incomplete translations of Pliny from the French had 
 appeared in 1565, and again in 1587. In 1601 Philemon 
 Holland, M.D. (1552-1637), in later life headmaster of 
 Coventry Grammar School " the translator generall in his 
 age," as Fuller calls him published a more complete version 
 of Pliny under the title " The History of the World, commonly 
 called the Natural Historic of Caius Plinius Secundus." 
 
218 Britain's Heritage of Science 
 
 This treats of all phases of nature, and contains a record 
 of all natural knowledge up to the time of the younger Pliny. 
 Nor must it be forgotten that the writings of Pliny and the 
 " Georgics " of Virgil were in constant use in the schools. 
 
 In the middle of the thirteenth century Roger Bacon 
 had pointed out that " There are two ways of knowing, 
 viz., by means of argument and by experiment," but for 
 three centuries onward it was " argument " which held the 
 field. Not that the sixteenth century failed to produce 
 enlightened men who were to preach a new doctrine. In 
 his educational work " De Tradendis Disciplinis " (1523) 
 Vives 1 advocates " nature study " and even uses the expres- 
 sion. He tells us " That although the writings of the old 
 Greeks and Romans are the opinions of learned men, yet 
 not even all these opinions and judgments are to be accepted." 
 Vives recommends that the pupil should first be shown what 
 he can most readily perceive by the senses : 
 
 " So will he observe the nature of things in the 
 heavens, in clouds and in sunshine, in the plains, on the 
 mountains, in the woods. Hence he will seek out and 
 get to know many things from those who inhabit those 
 spots. Let him have recourse, for instance, to gardeners, 
 husbandmen, shepherds, and hunters, for this is what 
 Pliny and other great authors undoubtedly did ; for any 
 one man cannot possibly make all observations without 
 help in such a multitude and variety of directions. But 
 whether he observes anything himself, or hears any- 
 one relating his experience, not only let him keep eyes 
 and ears intent, but his whole mind also, for great and 
 exact concentration is necessary in observing every part 
 of nature." 
 
 We can but judge the state of zoology in Queen Elizabeth's 
 time by the books and writings that have come down to us, 
 and if we inquire what books and writings were available, 
 they will be found to fall under the three headings, Medicine, 
 Meldcraft, and Heraldry. From these subjects the paths 
 of progress in that science were advancing and converging. 
 
 1 A Spanish educationalist who came to England in 1523 and was 
 attached to Henry VIII. 's Court. Later he lectured at Oxford and 
 became a Fellow of Corpus Christi College there 
 
Roger Bacon, Vesalius 219 
 
 The year that saw the birth of Shakespeare witnessed 
 in the remote island of Zante the death of Vesalius, who, 
 as a medical student at a hospital in Venice, had rubbed 
 shoulders with a young soldier, Ignatius Loyola, who six 
 years later founded the Order of the Jesuits. Vesalius, 
 who was born at Brussels on the last day of the year 1514, 
 was the first biologist to abandon authority. Dispensing 
 with the aid of unskilled barbers, he dissected the human 
 body with his own hands. Like Harvey, whose discovery 
 of the circulation of the blood dates but three years after 
 Skakespeare's death, he 
 
 " Sought for Truth in Truth's own Book, 
 The creatures, which by God Himself was writ, 
 
 And wisely thought 'twas fit, 
 Not to read Comments only upon it, 
 But on the original itself to look." 
 
 At the beginning of his scientific career, like his master 
 Sylvius, Professor at the College of France, Vesalius trusted 
 the written word of Galen more than he trusted his own 
 eyesight, but in the end his sight and his reason conquered, 
 and at last he taught only what he himself could see and 
 make his students see. 
 
 Vesalius was the founder of modern anatomy, physiology, 
 and, I think we may say, also of modern zoology and 
 botany, for the methods of these sciences are one. His 
 great work on " The Structure of the Human Body " 
 appeared at Basle in 1543, and was beginning to have 
 influence in England, but only amongst the learned, well 
 before the middle of the sixteenth century. 
 
 His English pupils, amongst whom was John Caius, 
 the third founder of Gonville and Caius College, helped to 
 spread his methods and principles in this country. Amongst 
 the many pupils of John Caius we may mention Thomas 
 Moffett. Comparatively few men in those days lived much 
 over fifty years, and Moffett, born in 1553, died in 1604. 
 He joined Trinity College in 1569, but migrated to Caius 
 in 1572, where he was nearly poisoned by eating mussels. 
 After taking his M.A. degree, he, as was the habit of the time, 
 studied abroad and received in 1578 the degree of M.D. 
 at Basle where he was a pupil of Felix Plater and of Zwinger. 
 
220 Britain's Heritage of Science 
 
 The following year he travelled in Spain and Italy, and in 
 these countries he made an elaborate study of the silk- 
 worm, which doubtless led him to the study of insects in 
 general. He not only wrote a poem on the silk-worm, 
 but collected notes on the natural history of the Insecta. 
 These were published thirty years after his death under the 
 title " Insectorum sive Minimorum Animalium Theatrum 
 ad vivum expressis Iconibus super quingentis illustratum." 
 An English translation entitled the " Theater of Insects " 
 was published as an appendix to Topsell's " History of 
 Four-Footed Beasts and Serpents-" in 1658. 
 
 Moffett was a many-sided man of science, a practising 
 physician, a traveller who at Copenhagen had known Tycho 
 Brahe, a courtier who took part in both diplomatic and 
 military service abroad, a poet and writer of epitaphs and 
 epigrams, a keen critic of diet, and for some time a member 
 of the House of Commons. 
 
 A friend of Moffett's was Thomas Penny, who entered 
 Trinity College, Cambridge, in 1550, and later became not 
 only a Prebendary of St. Paul's, but a sound botanist and 
 entomologist. Like so many men of the time, Penny 
 travelled extensively on the Continent. He visited Majorca, 
 lived in the south of France, and worked in Switzerland 
 with Gesner. He is believed to have been with Gesner 
 when he died, and he certainly helped to arrange the natu- 
 ral history specimens which the great master left. It was 
 probably through Penny that Gesner's drawings of butter- 
 flies passed into the care of Moffett, whose " Theatrum " 
 states on its title-page that it was begun by Edward 
 Wotton, Conrad Gesner, and Thomas Penny. 
 
 The contents of books revealing new knowledge diffused 
 themselves among the ordinary public in Queen Elizabeth's 
 time far more slowly than at present. On the other hand, 
 studies were then far less specialized than they now are. 
 For example, we find Milton placing medicine in the curri- 
 culum of a liberal education, and John Evelyn studying 
 " Physics " at Padua. Lord Herbert of Cherbury insists 
 on the necessity of a gentleman being able to diagnose and 
 treat disorders, and thinks he should have a knowledge of 
 anatomy, " Whosoever considers anatomy, I believe, will 
 
Thomas Moffett, Thomas Penny 221 
 
 never be an atheist," was one of his recorded sayings. 
 Dealing with the matter broadly, I think we may endorse the 
 statement of Mr. Foster Watson : "It is noteworthy, that 
 in both botany and zoology the main advances were made 
 by professed physicians," and we must not forget that Eliza- 
 bethan botany was more advanced than Elizabethan zoology. 
 
 Something, however, was learned from husbandry and 
 field sport. " Let the student," says Vives in the above- 
 quoted passage, " have recourse, for instance, to gardeners, 
 husbandmen, shepherds, and hunters," and in " De rebus 
 rusticis " he says : " Let the boy read Cato, Varro, Columella, 
 Palladius." " Vitruvius is important for naming with the 
 greatest purity and accuracy most objects of the country." 
 Virgil with his marvellous account of apiculture and other 
 agricultural pursuits was much read during this period. 
 
 The gentlefolk also in Queen Elizabeth's time were much 
 interested in the study of heraldry, for, indeed, it was a 
 very gentlemanly pursuit. Gerard Legh's " Accedens of 
 Armory " (1562) and John Guillim's " Display of Heraldry " 
 (1610) included descriptions of creatures which enabled the 
 owners of animal crests and supporters to appreciate the 
 nature of what they bore and of what supported them. 
 
 In Elizabethan times, although a knowledge of physio- 
 logy and human anatomy was beginning to emerge; such 
 objects as comparative anatomy, morphology, and embryo- 
 logy were non-existent. In dealing with the animal king- 
 dom, the first need of the earlier writers on zoology was to 
 make some sort of classification, and even in the later Tudor 
 times such attempts at classification rested almost wholly on 
 external characteristics. These arid catalogues of animals 
 were usually lightened by the addition of notes on their 
 habits often of the quaintest and most bizarre description 
 and by short accounts of such medical properties as the 
 fantastic pharmacy of the sixteenth century attributed to 
 various beasts. 
 
 With one or two exceptions astronomy on the physical 
 side, human anatomy on the biological the reawakening 
 in science lagged a century or more behind the renascence 
 in literature and in art. What the leaders of thought and 
 of practice in the arts of writing, of painting and of sculpture 
 
222 Britain's Heritage of Science 
 
 in western Europe were effecting in the latter part of the 
 fifteenth and throughout the sixteenth century began to 
 be paralleled in the investigations of the physical laws of 
 Nature only at the end of the sixteenth century and through- 
 out the first three quarters of the seventeenth. 
 
 Writing broadly, we may say that, during the Stewart 
 time, the sciences, as we now class them, were slowly but 
 surely separating themselves out from the general mass of 
 learning, segregating into secondary units; and from a 
 general amalgam of scientific knowledge, mathematics, 
 astronomy, physics, chemistry, geology, mineralogy, zoology, 
 botany, agriculture, even physiology (the offspring of anatomy 
 and chemistry) were beginning to assert claims to individual 
 and distinct existence. It was in the Stewart reigns that, 
 in England at any rate, the specialist began to emerge from 
 those who hitherto had " taken all knowledge to be " their 
 " province." Certain of the sciences, such as anatomy, 
 physiology and, to a great extent, zoology and botany, had 
 their inception in the art of medicine ; but the last two owed 
 much to the huntsman and the agriculturist. 
 
 The great outburst of scientific enquiry which occurred 
 during the seventeenth century was partly the result, and 
 partly the cause, of the invention of numerous new methods 
 and innumerable new instruments, by the use of which 
 advance in natural knowledge was immensely facilitated. 
 
 The barometer, the thermometer and the air pump, and, 
 later, the compound microscope, all came into being at the 
 earlier part of the seventeenth century, and by the middle 
 of the century were in the hands of whoever cared to use 
 them. Pepys, in 1664, acquired : 
 
 " a microscope and a scotoscope. For the first I 
 did give him 5 10s., a great price, but a most curious 
 bauble it is, and he says, as good, nay, the best he knows 
 in England. The other he gives me, and is of value; 
 and a curious curiosity it is to discover objects in a dark 
 room with." 
 
 Two years later, on August 19th, 1666, " comes by 
 agreement Mr. Reeves, bringing me a lantern " it must 
 have been a magic lantern " with pictures in glass, to make 
 strange things appear on a wall, very pretty." 
 
Francis Bacon 223 
 
 As we pass from Elizabethan to Stewart times, we pass, 
 in most branches of literature, from men of genius to men 
 of talent, clever men, but not, to use a Germanism, epoch- 
 making men. In science, however, where England led the 
 world, the descent became an ascent. We leave Dr. Dee 
 and Edward Kelly, and we arrive at Harvey and Newton. 
 
 The gap between the mediaeval science which still 
 obtained in Queen Elizabeth's time and the science of the 
 Stewarts was bridged by Francis Bacon, in a way, but only 
 in a way. He was a reformer of the scientific method. He 
 was no innovator in the inductive method; others had 
 preceded him, but he, from his great position, clearly pointed 
 out that the writers and leaders of his time observed and 
 recorded facts in favour of ideas other than those hitherto 
 sanctioned by authority. 
 
 Bacon left a heritage to English science. His writings 
 and his thoughts are not always clear, but he firmly held, 
 and, with the authority which his personal eminence gave 
 him, firmly proclaimed, that the careful and systematic 
 investigation of natural phenomena and their accurate record 
 would give to man a power in this world which, in his time, 
 was hardly to be conceived. What he believed, what he 
 preached, he did not practise. " I only sound the clarion, 
 but I enter not into the battle " ; and yet this is not wholly 
 true, for, on a wintry March day, in 1626, in the neighbour- 
 hood of Barnet, he caught the chill which ended his life while 
 stuffing a fowl with snow, to see if cold would delay putre- 
 faction. Harvey, who was working whilst Bacon was writing, 
 said of him : " He writes philosophy like a Lord Chancellor." 
 This, perhaps, is true, but his writings show him a man, 
 weak and pitiful in some respects, yet with an abiding hope, 
 a sustained object in life, one who sought through evil days 
 and in adverse conditions " for the glory of God and the 
 relief of man's estate." 
 
 Though Bacon did not make any one single advance in 
 natural knowledge though his precepts, as Whewell reminds 
 us, " are now practically useless " yet he used his great 
 talents, his high position, to enforce upon the world a new 
 method of wrenching from Nature her secrets and, with 
 tireless patience and untiring passion, impressed upon his 
 
224 Britain's Heritage of Science 
 
 contemporaries the conviction that there was t; a new 
 unexplored Kingdom of Knowledge within the reach and 
 grasp of man, if he will be humble enough, and patient 
 enough, and truthful enough to occupy it." 
 
 To turn to other evidence, the better diaries of any age 
 afford us, when faithfully written, as fair a clue as do the 
 dramatists of the average intelligent man's attitude towards 
 the general outlook of humanity on the problems of his ag;, 
 as they presented themselves to society at large. The 
 seventeenth century was unusually rich in volumes of auto- 
 biography and in diaries which the reading world will not 
 readily let die. The autobiography of the complaisant Lord 
 Herbert of Cherbury gives an interesting account of the 
 education of a highly-born youth at the end of the sixteenth 
 and the beginning of the seventeenth century. Lord Herbert 
 seems to have had a fair knowledge of Latin and Greek and 
 of logic when, in his thirteenth year, he went up to University 
 College, Oxford. Later, he " did attain the knowledge of 
 the French, Italian and Spanish languages," and, also, 
 learnt to sing his part at first sight in music and to play on 
 the lute. He approved of "so much logic as to enable men 
 to distinguish between truth and falsehood and help them to 
 discover fallacies, sophisms and that which the Schoolmen 
 call vicious arguments " ; and this, he considered, should 
 be followed by " some good sum of philosophy." He held 
 it also requisite to study geography, and this in no narrow 
 sense, laying stress upon the methods of government, 
 religions and manners of the several states as well as on their 
 relationships inter se and their policies. Though he advocated 
 an acquaintance with " the use of the celestial globes," he 
 did " not conceive yet the knowledge of judicial astronomy 
 so necessary, but only for general predictions; particular 
 events being neither intended by nor collected out of the 
 stars." Arithmetic and geometry he thought fit to learn, 
 as being most useful for keeping accounts and enabling a 
 gentleman to understand fortifications. 
 
 Perhaps the most characteristic feature of Lord Herbert's 
 acquirements was his knowledge of medicine and subjects 
 allied thereto. He conceived it a " fine study, and worthy 
 a gentleman to be a good botanic, that so he may know 
 
Lord Herbert, John Evelyn 225 
 
 the nature of all herbs and plants." Further, " it will become 
 a gentleman to have some knowledge in medicine especially 
 the diagnostic part " ; and he urged that a gentleman should 
 know how to make medicines himself. He gives us a list 
 of the " pharmacopeias and anechodalies " which he has 
 in his own library, and certainly he had a knowledge of 
 anatomy and of the healing art he refers to a wound which 
 penetrated to his father's " pia mater," a membrane for a 
 mention of which we should- *&s& in vain among the records 
 of modern ambassadors and gentlemen of the court. His 
 knowledge, however, was entirely empirical and founded 
 on the writings of Paracelsus and his followers; never- 
 theless, he prides himself on the cures he effected, and, 
 if one can trust the veracity of so self-satisfied an amateur 
 physician, they certainly fall but little short of the 
 miraculous. 
 
 John Evelyn, another example of a well-to-do and widely 
 cultivated man of the world, fond of dancing and skilled 
 in more than one musical instrument, was acquainted with 
 several foreign languages, including Spanish and German, and 
 was interested also in hieroglyphics. He studied medicine 
 in 1645 at Padua, and there acquired those " rare tables of 
 veins and nerves " which he afterwards gave to the Royal 
 Society; while at Paris, in 1647, he attended Lefevre's course 
 of chemistry, learned dancing and, above all, devoted himself 
 to horticulture. 
 
 But Evelyn's chief contribution to science, as already 
 indicated, was horticultural. He was devoted to his garden, 
 and, both at his native Wotton, and, later, at Sayes Court, 
 Deptford, spent much time in planting and planning land- 
 scape gardens, then much the fashion. 
 
 In the middle of the sixteenth century, the fact that 
 " nitre " promoted the growth of plants was beginning to 
 be recognized. Sir Kenelm Digby and the young Oxonian 
 John Mayow experimented de Sal-Nitro ; and, in 1675, 
 Evelyn writes : "I firmly believe that where saltpetre can 
 be obtained in plenty we should not need to find other 
 composts to ameliorate our ground." His well-known 
 " Sylva," published in 1664, had an immediate and a wide- 
 spread effect, and was, for many years, the standard book 
 
 P 
 
226 Britain's Heritage of Science 
 
 on the subject of the culture of trees. It is held to be 
 responsible for a great outbreak of tree-planting. The 
 introduction to Nisbet's edition gives figures which demon- 
 strate the shortage in the available supply of oak timber 
 during the seventeenth century. The charm of Evelyn's 
 style and the practical nature of his book, which ran into 
 four editions before the author's death, arrested this decline 
 ("be aye sticking in a tree; it will be growing, Jock, when 
 y're sleeping " as the laird of jfrtf^objadykes counselled his 
 son), and to the " Sylva " of John Evelyn is largely due the 
 fact that the oak timber used for the British ships which 
 fought the French in the eighteenth century sufficed, but 
 barely sufficed, for the national needs. 
 
 Pepys, whose naive and frank self-revelations have made 
 him the most popular and the most frequently read of diar- 
 ists, was not quite of the same class of student to which 
 Lord Herbert of Cherbury or John Evelyn belonged. But, 
 gifted as he was with an undying and insatiable curiosity, 
 nothing was too trivial or too odd for his notice and his 
 record; and, being an exceptionally able and hard-working 
 Government servant, he took great interest in anything 
 which was likely to affect the Navy. He discoursed with the 
 ingenious Dr. Kuffler " about his design to blow up ships," 
 noticed " the strange nature of the sea- water in a dark night, 
 that it seemed like fire upon every stroke of the oar " 
 an effect due, of course, to phosphorescent organisms float- 
 ing near the surface and interested himself incessantly in 
 marine matters. 
 
 Physiology and mortuary objects had, for him, an interest 
 which was almost morbid. He is told that " negroes drounded 
 look white, and lose their blackness, which I never heard 
 before," describes how " one of a great family was . . . 
 hanged with a silken halter . . . of his own preparing, 
 not for the honour only " but because it strangles more 
 quickly. He attended regularly the early meetings of the 
 Royal Society at Gresham College, and showed the liveliest 
 interest in various investigations on the transfusion of 
 blood, respiration under reduced air pressure and many 
 other ingenious experiments and observations by Sir George 
 Ent and others. On January 20th, 1665, he took home 
 
Samuel Pepys 227 
 
 " Micrographia," Hooke's book on microscopy " a most 
 excellent piece, of which I am very proud." 
 
 Although Pepys had no scientific training he only began 
 to learn the multiplication table when he was in his thirtieth 
 year, but, later, took the keenest pleasure in teaching it 
 to Mrs. Pepys one could have wished that Mrs. Pepys 1 
 views had been recorded he, nevertheless, attained to the 
 Presidentship of the Royal Society. He had always delighted 
 in the company of " the virtuosos " and, in 1662, three years 
 after he began to study arithmetic he was admitted a Fellow 
 of their the Royal Society. In 1681 he was elected 
 President. This post he owed, not to any genius for science, 
 or to any great invention or generalization, but to his very 
 exceptional powers as an organizer and as a man of business, 
 to his integrity and to the abiding interest he ever showed 
 in the cause of the advancement of knowledge. 
 
 It has been said that a competent man of science should 
 be able to put into language " understanded of the people " 
 any problem, no matter how complex, at which he is working. 
 This seems hardly possible in the twentieth century. To 
 explain to a trained histologist double B functions or to a 
 skilled mathematician the intricacies of karyokinesis would 
 take a very long time. The introduction in all the sciences 
 of technical words is due not to any spirit of perverseness 
 on the part of modern savants ; these terms, long as they 
 usually are, serve as the shorthand of science. In the Stewart 
 times, however, an investigator could explain in simple 
 language to his friends what he was doing, and the advance 
 of natural science was keenly followed by all sorts and 
 conditions of men. 
 
 Whatever were the political and moral deficiencies of 
 the Stewart kings, no one of them lacked intelligence in 
 things artistic and scientific. At Whitehall, Charles II. 
 had his " little elaboratory, under his closet, a pretty place," 1 
 and was working there but a day or two before his death, 
 his illness disinclining him for his wonted exercise. The 
 king took a curious interest in anatomy; on May llth, 
 1663, Pierce, the surgeon, tells Pepys " that the other day 
 
 1 Pepys, January 16th, 1669. 
 
 P 2 
 
228 Britain's Heritage of Science 
 
 Dr. Clerke and he did dissect two bodies, a man and a woman, 
 before the King, with which the King was highly pleased." 
 Pepys also records, February 17th, 1662-3, on the authority 
 of Edward Pickering, another story of a dissection in the 
 Royal closet by the king's own hands. 
 
229 
 
 CHAPTER IX 
 BOTANY 
 
 IT is generally conceded that the first eminent English 
 - botanist was William Turner (born probably between 
 1510 and 1515, died 1568), educated at Pembroke College, 
 Cambridge. After the manner of his time, Turner was not 
 only a botanist but a zoologist ; to his work in this subject 
 we shall return later; he was further a most polemical 
 divine, and suffered much with the alternate ebb and flow 
 of the varying religious faiths which prevailed in the country 
 during the Tudor times. Turner's earliest work on botany 
 was the " Libellus de re Herbaria novus," 1538, which may 
 also be regarded as the first English book on Botany. In 
 this he gives, for the first time, the locality of many of our 
 native British plants. Ten years later he published a work 
 on " Names of Herbes in Greke, Latin, Englishe, Duche, 
 and Frenche, with the commune names that Herbaries and 
 Apothecaries use." His best known work, however, was 
 his " Herball," which was published in three parts, the 
 first part appearing in 1551, the second when he was exiled 
 abroad in 1562, and the third in 1568. This was by no 
 means the first " Herball " which had appeared in English, 
 but it had a certain originality about it and a certain 
 independence of view. Turner was especially opposed to 
 what he considered superstitions in science, such as the old 
 legend about the mandrake ; but at the same time he seems 
 to have adopted and perpetuated the fable of the goose -tree 
 which bore barnacles from which geese hatched out. He 
 did not accept this myth without real enquiry and an effort 
 to obtain first-hand information, and he certainly would 
 never have written as Gerard wrote that, " he had seen 
 these trees with his own eyes, and had touched them with 
 his own hands." Turner's days were the days of herbals, 
 
230 Britain's Heritage of Science 
 
 and one cannot, perhaps, give a better description of what 
 a herbal was than by quoting the title-page of Lyte's (1529- 
 1607) Herbal, which was mainly a translation from the 
 French of De L'Ecluse, which was itself a translation from 
 the " Cruijdeboeck " of Dodoens. 
 
 " A niewe Herball, or Historic of Plants, wherein is 
 contayned the whole discourse and perfect description 
 of all sortes of Herbes and Plantes ; their divers and 
 sindry kindes; their straunge Figures, Fashions, and 
 Shapes ; their Names, Natures, Operations, and Vertues ; 
 and that not only of those which are here growing in 
 this our countrie of Englande, but of all others also of 
 foragne Realmes, commonly used in Physicke. First 
 set foorth in the Doutche or Almaigne tongue by that 
 learned D. Rembert Dodoens, Physition to the Emperour, 
 and now first translated out of Frenche into Englishe 
 by Henry Lyte, Escuyer." 
 
 This herbal went through several editions, but apart 
 from it Lyte made little contribution to English botany. 
 
 One especial merit which Turner had was accuracy of 
 observation, and a determination to see what he had to 
 describe. Hitherto, knowledge largely depended upon the 
 written word of the classical philosophers. Turner pre- 
 ferred to record his own experiences rather than to repeat 
 " Pliny's Hearsay." He named many British plants, and, 
 as Pulteney tells us, " allowing for the time when specifical 
 distinctions were not established, when almost all the small 
 plants were disregarded, and the Cryptogamia almost wholly 
 overlooked, the number he was acquainted with was much 
 beyond what could easily have been imagined in an original 
 writer on the subject." 
 
 Although other distinguished herbalists who followed hi 
 Turner's path in the main disregarded his work, there is 
 no doubt that he started a new era in the study of plants, 
 and we shall see later he did the same in the study of animals. 
 Another noted herbalist was John Gerard (1545-1612). 
 Unlike Turner, he was brought up to be a surgeon, and hi 
 his youth travelled extensively in Russia, Sweden, Norway, 
 and other parts of the Continent. To some extent he re- 
 garded plants from the medical point of view, and in what 
 
The Herbalists 231 
 
 was then the village of Holborn, he grew nearly 1,100 various 
 species of " simples." " The Herball or Generall Historic 
 of Plantes " is Gerard's claim to fame. Like Lyte's book, 
 it was based upon the works of Dodoens, and there was a 
 bitter quarrel as to the exact amount of credit due to the 
 author of the English edition. Being a physician, Gerard 
 naturally attached considerable importance to the medi- 
 cinal side of plants, but he was also a practical gardener, 
 and the popularity of his book probably depended to some 
 extent upon the fact that it was the first published in 
 English of practical use to horticulturists and gardeners. 
 
 One last herbalist may be mentioned, Thomas Johnson, 
 again a medical man with a physic garden of his own. He 
 was a botanist who travelled in the country inspecting and 
 recording the local flora, in fact his first publication was 
 on the flora of the county of Kent. But his claim to 
 mention depends upon his new edition of Gerard's " Herball," 
 which he enlarged, re-edited, and published in 1633. He 
 added some 800 plants which were unknown, or at any rate 
 unrecorded, by Gerard, and increased the number of figures 
 by 700, raising the total to over 2,700. Further and de- 
 tailed information on herbals may be found in Mrs. Arber's 
 delightful book on the English herbalists. 
 
 At the best, however, these herbals were full of super- 
 stitious and often nonsensical statements. They must 
 merely be regarded as catalogues, compilations as a rule 
 alphabetically arranged, for in the time when they mostly 
 flourished, plants had not been systematically sorted out. 
 Their affinities had not been established ; as Professor Green 
 says, " a herbal may be compared to a dictionary rather than 
 to any other form of book." 
 
 The next outstanding man in the history of British 
 botany is John Kay (1628-1705). He dealt with both 
 animals and plants, and what little space we can afford 
 for biographical details will be found under the chapter 
 dealing with Zoology. Like Turner and like so many other 
 botanists, Ray was a clergyman. He marks a new era in 
 the history of the science of Botany, partly on account of 
 his efforts towards a natural classification of plants, and 
 partly on account of his extreme accuracy in the use of 
 
232 Britain's Heritage of Science 
 
 words. He was, indeed, as Sir J. E. Smith said, " the most 
 accurate in observation, the most philosophical in contem- 
 plation, and the most faithful in description amongst all 
 the botanists of our own or perhaps any other time." In 
 his " Methodus Plantarum Nova " (1682), after recognizing 
 a certain indebtedness to Caesalpino and to Morison, the 
 first Professor of Botany at Oxford, he expounds his system 
 of classification and established, for the first time, the dis- 
 tinction between Dicotyledons and Monocotyledons. Also 
 here he showed the true nature of buds, and indicated many 
 of the Natural Orders which systematists now recognize. 
 
 Unfortunately, like other botanists of the time, he 
 retained the unnatural divisions of plants into trees, shrubs, 
 and herbs. Four years later, Ray published his first 
 volume of the " History of Plants," and, in 1688, the second 
 volume, the third and final volume appearing shortly before 
 his death in 1704. This work contains a description of 
 nearly 7,000 plants. In 1690 he re-edited the " Catalogus 
 Plantarum Anglise," which was the first manual of systematic 
 botany published in England, and was in constant use for 
 nearly a century afterwards. But Ray was far more than 
 a systematist ; in fact, he had a very wholesome and proper 
 disinclination for the founding of new species. As far as 
 appliances of the times went, he investigated the physiology 
 and the histology of plants. His researches on the move- 
 ments of plants and the ascent of sap were as complete as 
 they could be under the conditions prevailing during his 
 lifetime. He, with his colleague Willughby, studied the 
 bleeding of fresh-severed portions of the birch and the 
 sycamore, both of the branches and of the roots. He was 
 inclined, though not definitely decided, to accept the sexu- 
 ality of plants, and supported Grew by his knowledge of 
 the reproductive process in the animal kingdom. However, 
 he did not go further than " ut verisimilem tantum 
 admittamus." But later, he admitted, the male character 
 of the stamens which after all was giving the whole case 
 away. 
 
 Botany, without any doubt, owes a great deal to Ray. 
 As Miall has said, " he introduced many lasting improve- 
 ments fuller descriptions, better definitions, better asso- 
 
John Ray 
 
 From an original portrait 
 in the British Museum 
 
John Ray, Robert Morison 233 
 
 ciations, better sequences. He strove to rest his distinctions 
 upon knowledge of structure, which he personally investi- 
 gated at every opportunity." He sought for a natural 
 system and made considerable steps towards one. In his 
 classification he relied largely upon the nature of the fruit, 
 but he insisted also upon the importance of vegetative 
 habit. He laid stress upon the structure of the seed, appre- 
 ciated the fact that it not only contained an embryo, but 
 also the substance we now know as endosperm, but which 
 he called " medulla " or " pulpa." He made things much 
 easier for Linnaeus, as did Linnaeus in his turn for 
 naturalists who now smile at his mistakes. Both were 
 capable of proposing haphazard classifications, a fact which 
 need not surprise us when we reflect how much reason we 
 have to suspect that the best arrangements of birds, 
 teleostean fishes, insects and flowering plants known to 
 our own generation need to be largely recast. 
 
 A few words must be said about Robert Morison (1620- 
 1683), a contemporary and to some extent a rival of Ray's, 
 and whose system of classification for a time, but for a time 
 only, outshone Ray's. Morison was an Aberdonian and a 
 Royalist, and having been wounded at the battle of Brigg, 
 he removed to Paris, the asylum of many of his countrymen. 
 Here he took up the study of natural science, and ultimately 
 became the Superintendent of the fine garden of the Duke 
 of Orleans at Blois. On the death of the Duke in 1660, 
 Morison returned to England with Charles II., the Duke's 
 nephew. Charles gave him the title of " King's Physician 
 and Royal Professor of Botany," and made him Superin- 
 tendent of the Royal Gardens. Nine years later he was 
 elected " Botanic Professor " at Oxford, where he remained 
 until his death. 
 
 Ray, who was of humble origin, lived a simple life, and 
 was emphatically an open air naturalist. Morison, who 
 frequented courts and the higher walks of university life, 
 although to a certain extent a field naturalist, more than 
 Ray, relied on the works of his predecessors. After settling 
 at Oxford, he gave his whole energies to the production of 
 his " Historia Plantarum Universalis Oxoniensis." As an 
 example of what he wished the book to be, he published 
 
234 Britain's Heritage of Science 
 
 a monograph on the Umbelliferce, the first British mono- 
 graph devoted exclusively to the elucidation of a single 
 large Natural Order. The book was illustrated by some of 
 the first copper plates which were produced in these islands. 
 Morison endeavoured to trace the systematic relations of the 
 members of the family by the aid of a linear arrangement, 
 and even attempted a genealogical tree. He divided the 
 flowering plants into fifteen classes; but he was only able 
 to deal with five of these before his death, though he left 
 the four succeeding ones finished. The remainder were 
 completed by Jacob Bobart, the Superintendent of the 
 Gardens at Oxford. 
 
 Morison's families were too few in number, and conse- 
 quently often overcrowded with what later observation has 
 shown to be a heterogeneous collection of plants. He 
 worked from the particular to the general, beginning with 
 the smallest subdivisions and working up to the larger ones. 
 Like Ray, he accepted the division of plants into herbs, 
 shrubs, and trees; but, unlike Ray, he ignored the dis- 
 tinction between monocotyledons and dicotyledons. He 
 seems to have been a somewhat selfish man of science, 
 self-assertive, taking every credit to himself, while allowing 
 little to his predecessors and contemporaries. 
 
 During the latter half of the seventeenth century the 
 second name of quite outstanding merit in the history of 
 British Botany second to that of Ray is that of Nehemiah 
 Grew (1641-1712). Like Turner, he was educated at Pem- 
 broke College, Cambridge, and he subsequently studied 
 medicine at Leyden, where he took his doctor's degree in 
 1671. For a time he practised medicine at Coventry, and 
 later removed to London. He and his contemporary, the 
 Italian Malpighi, with whom he was always on good terms, 
 are regarded as the founders of vegetable anatomy. He 
 was the author of numerous works not all by any means 
 confined to botany. The greatest of his contributions to 
 that science was the " Anatomy of Plants," issued in 1684. 
 Sections I., II., and III. of this volume were second editions 
 of the " Anatomy of Vegetables Begun." The anatomy 
 of roots and the anatomy of trunks followed. The fourth 
 section included the anatomy of leaves, flowers, fruits, and 
 
Nehemiah Grew 235 
 
 seeds. The book was richly illustrated. Grew undoubtedly 
 saw for the first time many structural features in plants, 
 and although he was not always successful in interpreting 
 their functions, he added greatly to our knowledge. His 
 description of the bean-seed might still be used in a modern 
 Elementary Biology Class. He notes the cotyledons, and 
 states that the foramen (micropyle) " is not a hole casually 
 made, or by the breaking off of the stalk; but designedly 
 formed for the uses hereafter mentioned." He recalls that 
 when squeezed a bean seed gives rise to many small bubbles 
 through " the foramen." He notes the radicle, the plumule, 
 and the two seed-lobes, and is aware that the latter are a 
 particular kind of leaf " dissimilar leaves " he calls them, 
 and he finds that their parenchyma consists of an infinite 
 number of extremely small " bladders." He also notes 
 elsewhere that rows or files of " bladders " piled perpendicu- 
 larly one above each other at times break in upon one another, 
 and so make a " continued cavity." He recognized and 
 understood the resin passages in a pine tree, and describes 
 the medullary rays. He dwells upon the use of hooks in 
 climbing plants, and the fact that the various whorls of a 
 flower are arranged alternately. He invented the term 
 " parenchyma " and others still in use. He was aware of the 
 existence of stomata, and considers they were either " for 
 the better avulation of superfluous sap or for the admission 
 of air." To the flower itself he paid particular attention, 
 but failed to grasp the use of pollen. He was, however, the 
 first to point out that flowers are sexual, but unfortunately, 
 although he is fairly definite on the subject, he made few 
 experiments. He also described fully and completely the 
 sporangia of a fern. 
 
 Grew, like Ray, was a man of great piety, simplicity, 
 and undoubted modesty, and he considered that both 
 " plants and animals came at first out of the same Hand, 
 and were therefore the contrivance of tRe same Wisdom." 
 Hence he endeavoured to find analogies and homologies 
 between animals and vegetables, which later work could 
 not endorse. Like most of his contemporaries he interested 
 himself in the ascent of the sap, which he mainly attributed 
 to capillarity. He stated that the green colour of a plant 
 
236 Britain's Heritage of Science 
 
 * 
 
 was dependent upon its exposure to air, but he missed the 
 fact that the green colouring matter is dependent upon light. 
 He had noticed that many vegetable juices were turned 
 green by the addition of alkalies, and he considered that some 
 alkaline properties of the air produced the well-known colour 
 of leaves. He was groping after the fact that air was necessary 
 to a plant for its nutrition, though his ideas were by no means 
 definite. On the whole his greatest contribution to Science 
 is his discovery of the sexuality of plants; but that is at 
 least equalled or more than outweighed by his general contri- 
 butions to our knowledge of the anatomy of plants and to 
 the science of Botany in almost all its aspects. 
 
 The last half of the seventeenth century is distinguished 
 by the two names of Ray and Grew. Ray, unfortunately, 
 had no successor. Stephen Hales, with whom we now deal, 
 was the solitary follower of Grew until comparatively modern 
 times. 
 
 Stephen Hales (1671-1761) was born in Kent and belonged 
 to the same family as Sir Edward Hales, titular Earl of 
 Tenterden, the well-known Royalist. He was educated at 
 Corpus Christi College, Cambridge, where he was admitted 
 a Fellow in 1602-1603. As a resident of Cambridge he 
 " scoured the fields for Ray's plants," and worked in the 
 " laboratory at Trinity College." 
 
 In 1708-1709 he became perpetual curate of Teddington, 
 Middlesex, in which parish, although he held from time to 
 time other benefices, he mainly resided. Living not far from 
 Kew he was the friend of the royalties, and although Horace 
 Walpole called him " a poor good primitive creature," he 
 was greatly admired and respected by them, and was a 
 close friend of Pope's, whose will, in fact, he witnessed. 
 
 Sir Francis Darwin draws attention to the fact that 
 Hales' scientific work falls into two main classes : (1) physio- 
 logical and chemical, (2) inventions and suggestions on 
 matters connected with health and agriculture. It is with 
 the former we have mainly to deal. 
 
 Hales, as we have pointed out, was the single successor 
 in the eighteenth century of Nehemiah Grew, but in his 
 time scientific men were less specialized than they are now, 
 and Hales was not only a leader in vegetable physiology, 
 
Stephen Hales 
 
Stephen Hales 237 
 
 but an active researcher in animal physiology. He, in fact, 
 introduced into both fields of Physiology the process of 
 weighing and measuring. His experiments on the loss of 
 water which plants suffered by evaporation and on the 
 absorption of water by roots are classic, and still remain 
 of the greatest importance. His suggestion that the ascent 
 of the sap is not from the roots only but must proceed from 
 some power in the stem and branches, has recently met with 
 a certain amount of corroboration. He introduced a new 
 method by ever seeking a quantitative knowledge of the 
 various physiological functions he was enquiring into. He 
 experimented on the amount of rain and dew on special 
 areas of the ground, and on the expansive force that peas 
 exhibit when they absorb water, and explained variations 
 in pressure from hour to hour on the rate of growth of the 
 various members of the plant-organism, and all by methods 
 which are still in use. He was one of the first to oppose 
 the older views on the circulation of sap views which had 
 certainly retarded progress and at any rate he had some 
 inkling that air is a source of food to plants. He also had 
 a clear idea of the importance of scientific knowledge in its 
 practical application to agriculture. Without any doubt, 
 the Englishman Hales must be regarded as the founder of 
 that very important science, Plant Physiology. 
 
 Hales was a man of many inventions, and he devoted 
 his extraordinary ingenuity largely to improving the lot 
 of oppressed mankind. He invented various artificial 
 ventilators which were used in granaries, ships, and prisons, 
 and, so far as one can make out, the health of the prisoners 
 greatly benefited by the introduction of his appliances. 
 He also experimented on the distillation of salt water to 
 make it fresh, on the preservation of various forms of food 
 for sea voyages, on methods for cleaning harbours, and he 
 devised an instrument for deep-sea dredging which, together 
 with a large number of other mechanical contrivances, 
 occupied his ever active mind. 
 
 Hales was evidently a lovable, kindly character, and 
 without doubt was the greatest physiologist of his age, and 
 of many later ages. 
 
 One other man of science, although not a botanist, must 
 
238 Britain's Heritage of Science 
 
 be mentioned here because of his profoundly important 
 discovery in connexion with the function of leaves. It was 
 the chemist Joseph Priestley (1733-1804), who, while working 
 on the investigation of the air, states : "I have been so 
 happy as by accident to have hit upon a method of restoring 
 air which has been injured by the burning of candles, and 
 I have discovered at least one restorative which nature 
 employs for this purpose. It is vegetation." He records 
 in 1778 that the green deposit in some vessels which he was 
 using for his experiments gave off very " pure air," and 
 discovered that this exhalation was given off when the algse, 
 as they proved to be, were exposed to sunlight. 
 
 Thomas Andrew Knight (1759-1838) was the only out- 
 standing physiologist between Hales and the rise of the modern 
 school, and even he was more prominent as a horticulturist 
 than as a physiologist. He was educated at Balliol College, 
 Oxford, and, being in the possession of ample means, settled 
 first in Herefordshire and later at Downton, where he resided 
 until his death. He made the acquaintance of Sir Joseph 
 Banks, who was at that time seeking, on behalf of the Board 
 of Agriculture, certain correspondents who would answer 
 questions relating to agriculture in their several districts. 
 
 Knight was the second President of the Horticultural 
 Society, which had been founded in 1804. He was elected 
 in 1810, and occupied the Presidential Chair until his death. 
 
 His physiological investigations began with enquiries as 
 to the circulation of sap, and one of the methods of his 
 investigations was ringing the trees. He failed, however, 
 to appreciate the part that the leaf plays in nutrition, and 
 that the " function of the sap is to supply nutritive materials 
 to the various tissues and to circulate the manufactured 
 products of the leaf." 
 
 But, as Professor Green reminds us, Knight's work on 
 the ascent and descent of sap " did much that was not only 
 instructive for the time," but " was destined to remain with 
 little modification among the fundamental facts of science." 
 He made certain anatomical discoveries in connexion with 
 these physiological experiments, and he incidentally investi- 
 gated the transpiration or, as it was then called, " the 
 perspiration," of the leaf, and showed that it was chiefly 
 
Thomas Andrew, T. A. Knight 239 
 
 carried on by the under surface. His most important work 
 was, however, his investigations into the relation of plants 
 and their growth to the condition of their environment. 
 He had noticed that, however seeds are placed during 
 germination, the radicle attempts to descend into the earth 
 and the shoot attempts to ascend into the air. He used a 
 water-mill wheel in his garden, a wheel which revolved 
 rapidly on a horizontal axis on the edge of which he placed 
 his germinating seeds. He found that the shoots, no matter 
 how they were pointed at first, gradually turned their points 
 outwards from the circumference of the wheel, whilst the 
 radicles grew inwards, so that " in a few days their points 
 all met in the centre wheel." By this device Knight added 
 a new apparatus in the investigation of growth. Later he 
 paid much attention to the tendrils of Ampelopsis and the 
 clasps of ivy, noting that they showed a tendency to grow 
 away from the light. Much of his scientific work had 
 a utilitarian bias, and he published many papers of a strictly 
 horticultural nature. 
 
 In the management of his estate at Downton he experi- 
 mented continually on the raising of hybrids, and bred a 
 large number of new varieties of fruits and vegetables, many 
 of which still bear his name. 
 
 Knight was a man of great patience and great perseverance, 
 and seems to have had a charming personality, warm-hearted 
 and generous, a little hasty at times, but of great kindness. 
 
 Although Linnaeus (1707-1778) does not come within 
 the scope of this volume, a few lines must be devoted to the 
 great influence his views had on English thought. Without 
 being a great investigator he remodelled the art of description. 
 He introduced new and concise terms. He re-established 
 the binomial nomenclature of plants, and he devised an 
 artificial method of classification by means of which a com- 
 petent botanist could determine the genus and species of 
 almost any flower. But he was more of a co-ordinator than 
 an investigator. He added few new facts to science, and, 
 as Professor Green states, " we cannot find that either he 
 nor any of his immediate pupils made a single discovery of 
 any importance." His great talents lay in organization. He 
 had a gift for sorting out things and putting them into what 
 
240 Britain's Heritage of Science 
 
 he considered the right place. His sexual system of classifi- 
 cation was, as he himself felt, a merely temporary one, but 
 it caught on and for fifty years did much to hinder the pro- 
 gress of real scientific enquiry into the natural relationships 
 of plants inter se. 
 
 His name leads us on to Sir J. E. Smith (1759-1829), a 
 friend of Sir Joseph Banks. In fact it was at his breakfast 
 table that the news came that the mother of Linnaeus had 
 recently died, and that his collections were offered for sale. 
 Smith, who was a man of considerable means, purchased 
 the collections for a thousand guineas, and although the 
 Swedish Government are said to have sent a man-of-war to 
 retrieve them whilst they were yet at sea, they eluded the 
 pursuit if there was a pursuit and were landed in England 
 and arranged as speedily as possible by Smith, with the aid 
 of Sir Joseph Banks and his librarian Dryander. This 
 episode decided Smith to abandon the study of medicine 
 and take up that of botany, and to him the foundation of 
 the Linnsean Society is due. He was the author of many 
 books, and in 1790 he collaborated with Sower by in the 
 production of Sowerby's " English Botany," which extended 
 over thirty-six volumes, and in which he was responsible for 
 practically all the letter-press. Another notable work of 
 his, published in 1807, was an " Introduction to Physio- 
 logical and Systematic Botany," and the last seven years of 
 his life he devoted to the " English Flora." 
 
 We now turn to a class of men of science in which England 
 has always been pre-eminent the scientific explorer and 
 collector. 
 
 One of the earliest of these, Sir Hans Sloane (1660-1753), 
 started life as a doctor, having studied medicine at Paris and 
 Montpellier. He was well acquainted with the leading men 
 of science of his period, and for a time lived with Thomas 
 Sydenham. His great opportunity came in 1687, when he 
 accompanied, as physician, the Duke of Albemarle, Governor 
 of Jamaica, to the West Indies. Owing to the death of the 
 Duke, his stay in the islands was curtailed, but he came 
 back in 1689 with 800 species of plants and settled down to 
 medical practice. He became Secretary to the Royal Society 
 in 1693, and, while he was busily at work on his collections, 
 
T. A. Knight, Sir Joseph Banks 241 
 
 found time to contribute a number of papers to the Philo- 
 sophical Transactions. 
 
 On the death of Sir Isaac Newton he followed him as 
 President of the Royal Society, and occupied the chair for 
 twenty-eight years, until 1740. Perhaps his greatest con- 
 tribution to botany was in connexion with the Physic 
 Garden of Chelsea. He had purchased the manor of that 
 village in 1712, and on retiring from practice settled on his 
 estate. This included the site of a " Physic " garden estab- 
 lished, in 1673, by the Apothecaries' Society, and Sloane 
 handed, in 1722, the fee simple of the property to that body, 
 subject to certain conditions. His name is commemorated 
 on the Cadogan Estate in the West End of London by Sloane 
 Square and Hans Place. 
 
 A second explorer, " the greatest Englishman of his time," 
 traveller and prominent collector, was Sir Joseph Banks 
 (1743-1820), who was educated both at Harrow and Eton. 
 At school he was so immoderately fond of play that his 
 masters found great difficulty in fixing his attention on his 
 studies, but at the age of fourteen, impressed by the beauties 
 of flowers in the country lanes, he decided to study botany, 
 and probably his real education was largely due to the women 
 who were then, as they are now, collecting " simples " for 
 druggists' shops. At Oxford, where he found no lectures were 
 being delivered on his favourite subject, he obtained per- 
 mission to procure a teacher to be paid by the students, and 
 coming over to Cambridge he brought back with him to his own 
 university Israel Lyons, the astronomer and botanist. I wonder 
 if any student has ever attempted such an enterprise since ! 
 
 Banks was a wealthy man and was able to indulge 
 his passion for travelling. His first journey was to New- 
 foundland, and after his return, via Lisbon, he came across 
 Dr. Daniel Solander, the faithful pupil of Linnaeus, who 
 subsequently accompanied him in his voyage round the 
 world, for Banks left England in August 1768 on Captain 
 Cook's Endeavour. The scientific part of the expedition was 
 financed by Banks, and he was accompanied not only by 
 Dr. Solander but by two artists and two attendants. It 
 would take too much space to dwell upon that remarkable 
 voyage, Banks was collecting not only plants, but animals, 
 
 Q 
 
242 Britain's Heritage of Science 
 
 and noted, as an ancient writer said, " ye beastlie devices 
 of ye heathen." At a spot they christened Botany Bay, 
 owing to the wealth of plant life in the district, kangaroos 
 were observed for the first time. 
 
 The Endeavour returned in the spring of 1771, and Banks 
 very shortly afterwards made arrangements (which ulti- 
 mately fell through) to accompany Captain Cook on a second 
 voyage in the Resolution. Being disappointed over this 
 expedition, Banks visited Iceland with his scientific staff 
 and Dr. Solander. This was the last of his travels. 
 
 He became President of the Royal Society in 1778, and 
 held that distinguished office until his death. For a time his 
 reign was a troubled one. The secretaries had assumed, as 
 secretaries often do, a power which belonged to others, and 
 Banks was determined to put this right. The dissensions 
 that followed led to a secession of several members, but the 
 majority remained and harmony was once more restored. 
 
 The contributions that Banks made to science by personal 
 investigation were comparatively few, but he was a great 
 patron of Natural History, and although he wrote little, 
 he was the cause of much writing by others. He made his 
 collections accessible to men of science, and his house in 
 Soho Square was a rallying spot for those interested in 
 Natural History. His library was one of the finest then 
 existing, the catalogue of it by Dryander exists in five 
 volumes. The library is still kept in a room by itself in the 
 British Museum. Although apparently a bit of an autocrat, 
 he was a generous and far-seeing man, and those who knew 
 him best undoubtedly loved him most. 
 
 The Linnsean system was destined to disappear, and 
 during the first decades of the nineteenth century it was 
 being gradually replaced by a more natural and scientific 
 scheme of classification. In this, England practically led 
 the way, and, indeed, Professor Green tells us that with 
 Robert Brown began " a long line of taxonomists of the 
 greatest brilliance, who not only outshone all their prede- 
 cessors, but carried the nation's prestige in botany to a pitch 
 that had not been reached even under the influence of Ray." 
 
 Brilliant and stimulating as were the speculations of 
 the French School from De Jussieu to De Candolle, the 
 
Sir Joseph Banks, Robert Brown 243 
 
 English were at least their levels in the study of the 
 herbarium. Where they outshone all other nations was in 
 their world-wide explorations, their vast collections of extra- 
 European plants, which laid the foundation of the science 
 of geographic botany and afforded the material which was 
 destined to form the basis of the speculations as to the 
 " Origin of Species " which were so prominent a feature in 
 the latter part of the nineteenth century. 
 
 Robert Brown (1773-1858), one of the most brilliant 
 men of science Europe has produced, was the son of the 
 Episcopalian minister in Montrose. He was educated partly 
 at Aberdeen and partly at Edinburgh, where, for the first 
 time, he showed the interest which never afterwards failed 
 him in the science of botany. In 1795 he obtained a double 
 commission as Ensign and Assistant Surgeon in the Fife- 
 shire Regiment of Eencible Infantry, and proceeded to 
 Ireland. In 1798, being sent to England on a recruiting 
 service, he became the friend of Sir Joseph Banks, who 
 was destined to help him in no common measure. It was 
 owing, indeed, to Banks that he resigned his commission and 
 started on his memorable voyage to Australia and Tasmania. 
 He left Portsmouth in 1801 under the command of Captain 
 Flinders, and was away about four years. The South Coast 
 of Australia, the tropical part of the East Coast and part 
 of the North were explored before Flinders was compelled 
 to return to England by the bad state of his ship. The 
 botanists, however, remained in Australia for another year 
 and a half, and extended their investigations to Tasmania 
 and other islands. Altogether about 4,000 species of plants 
 were collected, and on his return to England in 1805 these 
 great collections, added to those which Sir Joseph had 
 brought back from Captain Cook's circumnavigation of the 
 globe, and those due to other explorers, were now thoroughly 
 worked out by Brown. As Asa Gray remarks : 
 
 " It was the wonderful sagacity and insight which 
 he evinced in these investigations which, soon after his 
 return from Australia, revealed the master mind in 
 botanical science, and ere long gave him the position of 
 almost unchallenged eminence, which he retained without 
 effort for more than a century." 
 
 Q2 
 
244 Britain's Heritage of Science 
 
 The result of these researches was the work " Prodromus 
 Florae Novae Hollandiae et Insulse Van Dieman," a work 
 marked by singular accuracy of detail set forth in precise 
 and clear language ; it showed, moreover, a profound mastery 
 of the principles of classification. 
 
 Another important publication of Brown was his mono- 
 graph on the Proteacece, which contained one of his first great 
 contributions to Histology, namely, that dealing with the 
 structure of the seed. Brown was also the first to recognize 
 the true nature of the seed in Gymnosperms. He paid 
 much attention to the structure of the flower and the 
 methods of pollination, especially in the Natural Orders 
 Orchidece and Asclepiadece. In fact, so important did his 
 work appear to foreigners, that Humboldt dedicated his 
 " Synopsis Plantarum Orbis novi " to him in the following 
 words : " Roberto Brownio Britanniarium glorias atque 
 ornamento." We have no space to follow further his tireless 
 work on classification. 
 
 Brown, who had succeeded Dryander as librarian to 
 Sir Joseph Banks in 1810, at the latter's death in 1820 
 succeeded to the use and enjoyment of his collections and 
 library, together with the house in Soho Square, where 
 for nearly sixty years he had pursued his investigations. 
 More than once during his life he had been offered professor- 
 ships, but he was essentially a researcher, and preferred 
 the quiet of Soho Square, which has been so well described 
 by Dickens in the "Tale of Two Cities." Indeed, the 
 character of Dr. Manette might almost have been drawn 
 from Brown, for, as a friend wrote of him, " I loved him for 
 his truth, his simple modesty, and, above all, for his more 
 than woman's tenderness. Of all the persons I have known, 
 I have never known his equal in kindliness of nature." 
 
 Before passing on, one must not omit to mention that 
 in his monograph on the Orchidece Brown first announced 
 the discovery of the nucleus in the vegetable cell. He is 
 also the discoverer of the so-called Brownian movement 
 an irregular trembling motion of very small particles sus- 
 pended in liquids which becomes visible under the micro- 
 scope, when high magnifying powers are applied. It is 
 connected with the thermal motion of the molecules of 
 
John Lindley 245 
 
 the liquids, and has gained some importance in recent 
 years. 
 
 Although Brown did much to undermine the Linnaean 
 system, it was not by a frontal attack so much as by 
 courteously and consistently ignoring it. 
 
 John Lindley (1799-1865) took more direct action. Lind- 
 ley was born near Norwich, where he was educated. His 
 father was a nurseryman, and throughout his life Lindley 
 showed a particular interest in all horticultural matters. In 
 1819 he went to London, and shortly afterwards was 
 appointed Garden Assistant Secretary to the Horticultural 
 Society, and in 1830 Secretary to the Society. It was his 
 efforts, combined with those of Bentham, which rescued the 
 Society from financial disaster, and organised the very 
 successful series of exhibitions of flowers and vegetables, 
 the first " flower-shows " recorded in Great Britain. 
 
 In 1829 he was elected Professor of Botany at University 
 College, London, and was the first occupant of that Chair. 
 His lectures were singularly concise and clear, and attracted 
 large classes. Throughout his life he was a constant advocate 
 of a natural system of classification as opposed to the 
 artificial one of Linnaeus, and in 1829 he published a " Synopsis 
 of the British Flora," which was one of the first attempts 
 to arrange British plants on a basis of natural affinity. The 
 following year, in an Introduction to the " Natural System 
 of Botany," he put forward, tentatively, his natural classifi- 
 cation. He helped Loudon to bring out his " Encyclopaedia 
 of Gardening," wrote much for the " Penny Encyclopaedia," 
 collaborated with Hutton in the " Fossil Flora of Great 
 Britain," and with Sir Joseph Paxton in a work entitled 
 " Paxton's Flower Garden," and in 1821 started the well- 
 known " Gardener's Chronicle," which he edited for twenty- 
 five years. 
 
 Although experts do not admit that Lindley achieved 
 any permanent success in framing his classification, he was 
 undoubtedly a great taxonomist. He was celebrated for the 
 completeness of his descriptions of the several Natural Orders 
 and valued for his clear discussions on their inter-relation- 
 ships. He was an extremely hard worker, and took a large 
 share in administrative work; towards the end of his life 
 
246 Britain's Heritage of Science 
 
 he acted for the Government in the preparation for the 
 Great Exhibition of 1851, and undertook the entire charge 
 of the Colonial Department in the following Exhibition of 
 1862. Lindley's only son is the present Lord Lindley. 
 
 Born in the saifie neighbourhood and educated at the 
 same school a few years before Lindley, Sir William Jackson 
 Hooker (1785-1865) was another example of a biologist 
 who commenced his scientific life as a traveller. In 1809, 
 on the advice of Sir Joseph Banks, he visited Iceland, but 
 unfortunately lost his collections by the burning of the ship 
 on the return voyage. He wished to accompany Sir Robert 
 Brownrigg, the recently appointed Governor of Ceylon, but 
 the disturbed state of the Island prevented his carrying 
 out his intentions. 
 
 In 1820 he accepted the Professorship of Botany at 
 Glasgow, where he was singularly successful as a teacher. 
 In 1841 he was appointed Director of the Royal Gardens at 
 Kew, and we shall have to consider later his work there. 
 He had always been a great collector, and his herbarium, 
 which was far the richest ever accumulated in his lifetime by 
 any one man, was bought by the nation after his death. 
 Though much engaged in official duties, he was, neverthe- 
 less, a great writer, and produced over one hundred memoirs 
 and volumes on Economic and Systematic Botany. He was 
 particularly happy in his relations with the officials in the 
 Greater Britain beyond the seas, and inaugurated a series 
 of Colonial floras, which have proved of great value. He 
 was one of those men always anxious to help others, and he 
 readily placed his knowledge and his collections at the 
 disposal of younger men. So busy a life left little time 
 for society, but Darwin records " his remarkably cordial, 
 courteous, and frank bearing." 
 
 Another contemporary was George Bentham (1800-1884), 
 a nephew of Jeremy Bentham. He was brought up abroad, 
 and had a wide acquaintance with the flora of Southern 
 France. In 1821 he returned to England, and at once made 
 the acquaintance of the leading botanists of the time, and 
 very soon took a prominent position himself as a systematic 
 botanist. He contributed the " Flora of Hong Kong " and 
 the " Flora Australiensis " to Sir William J. Hooker's 
 
W. J. Hooker, G. Bentham, J. D. Hooker 247 
 
 Colonial Floras. But his great work was the " Genera 
 Plant arum," in the execution of which he was associated with 
 Sir Joseph D. Hooker. One must not forget to mention 
 his " Handbook of the British Flora," published in 1858. 
 He was a man endowed with a gift of accuracy, discrimina- 
 tion and precision, and with infinite powers for hard work. 
 He handled collections of plants from every quarter of the 
 globe, and, as one of the most distinguished contemporaries 
 remarked, he possessed " an insight, of so special a character 
 as to be genius, into the relative value of characters for 
 practical systematic work a sure grading of essentials and 
 non-essentials." 
 
 Bentham was an untiring worker, and it was character- 
 istic of him that having finished, after a year's incessant 
 work for the " Genera Plantarum," whose publication 
 extended from 1862-1883, the Orchidacece on a certain 
 Saturday afternoon, he bade the attendant at the Herbarium 
 to bring down the material for commencing the much more 
 difficult group of the Grasses. It is impossible here to enu- 
 merate the numerous papers and memoirs which Bentham 
 published, and one can only sum him up by saying that he 
 was one of the greatest systematic botanists who ever lived ; 
 his colleague, Hooker, said of him " There is scarcely a 
 Natural Order that he did not more or less remodel." 
 
 A contemporary of Bentham and the vounger son of Sir 
 W. J. Hooker was Sir Joseph Dalton Hooker (1817-1911). 
 The younger Hooker is another example so common in 
 British biological science of men who approach their subjects 
 through extensive travel. Inspired by his father he, as a 
 boy, took an intense interest in botanical research, but, 
 like all young men, he was eager to travel, to see the world. 
 He qualified as a Doctor of Medicine at Glasgow, and was 
 delighted when Sir James Clark Ross offered to take him 
 as assistant surgeon and analyst on his ship the Erebus to 
 the Antarctic. When the expedition returned in 1843, 
 Hooker devoted himself to publishing the botanical results 
 of the voyage. These filled six quarto volumes. 
 
 At about this date the intercourse between Darwin and the 
 younger Hooker became closer, and there was a constant inter- 
 change of correspondence between the two contemporaries. 
 
248 Britain's Heritage of Science 
 
 Hooker's researches, especially on the flora of the Gala- 
 pagos, had convinced him that there was an evolution in 
 space. On the one hand he found that the plants of 
 neighbouring hills, though related, differed in detail; on 
 the other hand, identical species were often found on hills 
 separated by many thousand miles of ocean. Hooker was 
 the first to whom Darwin confided his theories of natural 
 selection, and he read for his friend the proofs of the first 
 sketch of the " Origin of Species." In fact, Darwin wrote 
 to him " for years I have looked on you as a man whose 
 opinion I valued on any scientific subject more than anyone 
 else in the world." 
 
 In 1845 J. D. Hooker was appointed Botanist to the 
 Geological Survey, and for a time turned his attention to 
 fossil botany. But his love of travel was not yet sated, 
 and in 1847 he started to explore the Himalayas. He spent 
 part of two years in exploring Sikkim, and for a time was 
 imprisoned. He also explored part of Nepal, and visited 
 territory which has not even yet been re-investigated. He 
 penetrated some way into Tibet, and one afternoon at his 
 house in Sunningdale he received a telegram from the Lhassa 
 Expedition of 1903, stating that they had got as far as he had 
 previously penetrated, and congratulating him upon the 
 usefulness of his survey. Having explored Eastern Bengal 
 and the Khasia Hills, he returned to England in 1851, and 
 in 1855 he was appointed Assistant Director to his father at 
 Kew, and ten years later succeeded his father as Director. 
 
 On his return form India, he immediately commenced, 
 in conjunction with Thomas, the first volume of the " Flora 
 Indica," which, however, also proved to be the last, as it 
 was planned on too ambitious a scale. In 1860 he visited 
 and examined considerable areas of Syria, and about this time 
 he was contemplating his celebrated " Genera Plantarum." 
 But the call of the world still held him, and in 1871 this 
 indefatigable traveller, accompanied by John Ball and Maw, 
 made an expedition into Morocco. They were the first 
 Europeans to ascend the Tagherot Pass, nearly twelve 
 thousand feet high. 
 
 In 1873 Hooker became President of the Royal Society, 
 and he made a real effort to bring that Institution into closer 
 
Sir Joseph Dalton Hooker 249 
 
 touch with the social life of the community. He was suc- 
 cessful in raising the sum of 10,000 to aid the somewhat 
 exiguous resources of the Society. In 1877 he obtained 
 leave of absence to visit the Rocky Mountains of Colorado 
 and Utah, and added much to our knowledge of the fossil 
 flora of those districts, and later he returned to his first love 
 and made a determined effort to complete his " Flora of 
 British India," which was accomplished in seven volumes 
 during the next fourteen years. In 1885 he retired from the 
 Directorship of Kew, and was succeeded by Sir William 
 Thiselton-Dyer, but he never ceased working. 
 
 Hooker was the recipient of numerous honours, including 
 the O.M., which was personally presented to him at Sunning- 
 dale, to which village he had retired, on behalf of King 
 Edward VII. on his ninetieth birthday. 
 
 Hooker stands out as the greatest authority the world 
 has yet produced on the subject of the Distribution of Plants ; 
 although he did much other work, this alone confers on him 
 immortality. 
 
 Hooker was capable of enduring great physical fatigue, 
 capable of working continuously with very short intervals of 
 sleep. Somewhat highly strung he disliked public functions, 
 though when forced to do so he could make an eloquent and 
 stirring speech. He was extremely kind and courteous, and 
 always ready to help the younger men. He retained his 
 faculties to the last, and continued to work to the end of his 
 long, laborious, and successful life. 
 
 We have seen that most of the progress of the physiology 
 of plants was due to British workers; but naturally in the 
 last quarter of the eighteenth century Great Britain had to 
 some extent remained isolated from the science of the 
 continent, and the currents of botanical thought flowed at 
 somewhat different angles on the two sides of the Channel. 
 We shall see later how Huxley inaugurated a new departure 
 in the teaching of biology, and with him came the laboratory. 
 Hitherto the botanists had been content with their botanic 
 gardens, their herbaria, and with a few roughly devised 
 physiological instruments. With " the coming of the labora- 
 tory," however, things altered. Huxley had round him an 
 ardent body of young workers. His first demonstrators 
 
250 Britain's Heritage of Science 
 
 were Michael Foster, Ray Lankester, and Rutherford, and 
 later Newall Martin (who collaborated with his chief in the 
 production of the " Elementary Biology "), Thiselton-Dyer, 
 and Vines. The coming of the laboratory was slower at 
 the Universities, but with the arrival of Foster at Cambridge, 
 and the return for a time of the old Cambridge men, Martin 
 and Vines, laboratory instruction became part of the normal 
 course. 
 
 The modern study of Cryptogamic Botany in England 
 may almost be said to begin with the works of Miles Joseph 
 Berkeley (1803-1889). Like so many English botanists he 
 was in Holy Orders. Coming from Oundle and Rugby to 
 Christ's College, Cambridge, he came under the influence of 
 Henslow, and took his degree in 1825. At first he worked 
 on the Algae, but in 1836 he published, in connexion with 
 Smith's " English Flora " the section which dealt with the 
 fungi, and this was the earliest of his many contributions 
 on this group. He was the first to throw light upon the 
 fungoid organism Phytophthera infestans, which caused the 
 potato disease connected with the appalling famine in Ireland 
 in 1846. 
 
 Between 1844 and 1856 his " Decades of Fungi " were 
 published and were amongst the most conspicuous of con- 
 temporary publications on this subject. Berkeley paid 
 particular attention to the diseases of plants, and contributed 
 a series of articles to Lindley's newly-established " Gardener's 
 Chronicle." For many years he was the authority at Kew 
 on Cryptogamic Botany. He described the fungi collected 
 by his fellow-collegian, Darwin, on the Beagle, and his classical 
 knowledge was of great use to Bentham and Hooker in their 
 " Genera Plantarum." His large collections of algae were left 
 to Cambridge, whilst his fungi went to Kew. 
 
 During his lifetime he was easily leader in the taxonomy 
 of the subject, and he may almost be said to have started 
 a new line of research. His most distinguished successor 
 was Marshall Ward, who will be dealt with more fully under 
 the Cambridge School. 
 
 The great majority of the earlier botanists hitherto 
 mentioned li ved and worked in London, but a small minority 
 carried on their researches in country houses or, more often, 
 
M. J. Berkeley, W. Sherard, C. G. Daubeny 251 
 
 in country parsonages. But there are other centres of 
 activity in England, though none of them, till the re-awakening 
 of science at the end of the nineteenth century, produced 
 men of very outstanding talent. 
 
 We have seen that Morison was the first Professor of 
 Botany at Oxford he was appointed Professor in 1669 
 although when he was appointed the Botanic Garden at 
 Oxford had already been in being for thirty-seven years. 
 His successors, however, were people of comparatively little 
 importance ; the Professorship was always very inadequately 
 endowed. In 1728 William Sherard (1659-1728), who was 
 more of a patron of science than a man of science, left by 
 will a sum to re-endow the Professorship, which was now 
 named after him, and this was at first occupied by the German 
 Dillenius (1687-1747), who was undoubtedly one of the great 
 botanists in Great Britain during the eighteenth century; 
 but his work, though painstaking and laborious, showed little 
 originality and insight. His knowledge, however, was great, 
 and was recognized by his contemporaries at the time. 
 Perhaps his greatest work was the " Historia Muscorum," 
 which appeared in 1741. As Professor Green says, "it is 
 a work of colossal labour, but it is impossible to avoid a 
 certain feeling of disappointment with the " Historia," not that 
 it was not good but that it might have been so much better." 
 Dillenius was, however, conservative in his thought, and a 
 man without a great faculty for new enterprise. After his 
 death, botany again fell under a cloud at Oxford, and for 
 a time at any rate Cambridge took the lead. 
 
 One must, however, mention Sibthorp (1758-1796), who, 
 always impressed with the relation of his science to agri- 
 culture, founded the Professorship of Rural Economy which 
 now bears his name. 
 
 In 1834 the School of Botany at Oxford woke up. Pro- 
 fessor Charles Giles Daubeny (1795-1867) of Magdalen College 
 was, as men of science were in those days, very versatile, he 
 was almost equally distinguished as a geologist^ a chemist, 
 and a botanist. And again, after the manner of those times, 
 he did not hesitate to hold contemporaneously three pro- 
 fessorships. For in 1822 he became Professor of Chemistry, 
 and only resigned it in 1855, and in 1834 Sherardian Professor 
 
252 Britain's Heritage of Science 
 
 of Botany, and in 1840 Sibthorpian Professor of Rural 
 Economy. It is not our intention in this volume to deal 
 with agriculture, but one might at least indicate that he 
 was one of the earliest to throw light on the principles involved 
 in the rotation of crops, to investigate the constituents of 
 plant ashes, to show the difference between " the total amount 
 of the salts contained in the soil and the amount available 
 for use by the plant," and above all he had a keen appreciation 
 of the part that the fungi play in diseases of plants. 
 
 Daubeny remodelled the beautiful Botanic Gardens at 
 Oxford and founded the Botanic Museum. He was a keen 
 supporter of Darwin's views of Natural Selection, and spoke 
 strongly in their favour at the meeting of the British 
 Association in 1860. 
 
 If we now turn to Cambridge we again find no name of 
 absolutely outstanding merit until the revival of science at 
 the end of the nineteenth century. 
 
 A few words should, however, be said about the second 
 Martyn, who succeeded his father to the Professorship in 
 the year 1761. Thomas Martyn (1735-1825) was a parson, 
 and in 1762 he was elected to succeed his father to 
 the Chair of Botany, which he held for the astonishing 
 period of sixty-three years. He was, however, as professors 
 were apt to be in those times, largely non-resident, and he 
 ceased lecturing altogether in 1796. But for many years 
 before that date he had been out of residence, and only 
 returned from time to time to what was obviously an 
 uninterested audience. 
 
 Henslow (1796-1861), who succeeded Martyn, was a 
 different kind of man, and did much to encourage the advance 
 of science in many directions. For a time he held the Chair 
 of Mineralogy, having been appointed at the age of twenty- 
 six, together with the Chair of Botany, but he devoted 
 most of his energy to the latter subject, and his lectures 
 attracted large audiences. He used many illustrations, and 
 for the first time introduced what was later destined to 
 develop into practical laboratory work. He reorganized 
 the Botanic Garden, and during his time it was moved to 
 its present site, and for the first time organized systematic 
 excursions in the neighbouring country. His success in 
 
T. Martyn, H. Marshall Ward 253 
 
 interesting Suffolk farmers in his parish in the application 
 of Botany to Agriculture was notable. He is renowned 
 not for any strikingly remarkable original contributions to 
 science, but for taking a leading part in reorganizing the 
 scientific spirit of Cambridge. 
 
 The only other botanist of eminence connected with 
 Cambridge was Professor Marshall Ward (1854-1906). He was, 
 in a way, a successor of Berkeley, and although he always 
 was very nervous of the encroachment of what is known as 
 " technical research " on the purer kind, his own researches 
 were without exception of practical utilitarian value. Ward, 
 like Berkeley, was educated at Christ's College, and afterwards 
 studied in Germany. For a time he was teaching at Owens 
 College, Manchester, and later he was Professor of Botany 
 in the Forestry Department of the Royal Engineering College 
 at Cooper's Hill; he was appointed Professor at Cambridge 
 in the year 1895. One of his earliest researches involved a 
 visit to Ceylon, where he investigated the life-history of the 
 fungus that attacks the leaves of the coffee plant, which in 
 fact destroyed the coffee trade of that island. He worked 
 out the life-history of this pathogenic fungus, and was largely 
 instrumental in inducing the planters to take up the planting 
 of tea. 
 
 Throughout his life Ward was largely occupied with the 
 study of bacteria and fungi, to which he contributed much 
 of first-rate importance. During his professorship the 
 present School of Botany was erected and equipped, and 
 at the time of its erection it was, and still is, second to none 
 in Great Britain in size and completeness of equipment. 
 
 The history of Botany in Scotland and in Ireland 
 shows, as at first was the case in Cambridge and Oxford, no 
 particularly outstanding names. The University Chair in 
 Edinburgh was founded in 1695, and was first filled by James 
 Sutherland (1639-1719), who, in 1667, had succeeded in estab- 
 lishing and stocking a small botanic garden. At Glasgow, 
 from the year 1719, Botany no longer had a distinct professor, 
 the subject being taught by the Professor of Anatomy, a 
 separate Chair reappearing only in the year 1818. The first 
 occupant of this double chair was Thomas Brisbane, a man 
 who entertained so strong a dislike to dissection, that it is 
 
254 Britain's Heritage of Science 
 
 believed he never taught anatomy at all. It cannot be said 
 that his teaching in botany in any way compensated for this 
 silence in anatomy. The curious conjunction of the two 
 professorships did not produce anyone of any particular 
 eminence in botanic science. B. K. Greville (1794-1866), 
 who held no official post, was, however, establishing a great 
 reputation for his knowledge of cryptogamic botany, in 
 which subject he is said to have done more than any botanist 
 of his times. 
 
 Hooker, whose work is mentioned elsewhere, succeeded 
 Graham as Professor of Botany at Glasgow, and for a time 
 the chief activity in this science was in the western rather 
 than the eastern university. 
 
 On Graham's succeeding to the Chair in Edinburgh, 
 Botany again revived, for he was an able lecturer, a man 
 of great activity, and he organized botanical excursions for 
 his pupils. 
 
 He was succeeded by J. H. Balfour (1808-1884), a brilliant 
 teacher and a most genial man, called by his pupils " woody 
 fibre." He was known best, perhaps, as a teacher than as 
 an investigator, and, as was usual during the times in which 
 he lived, his researches were largely of a systematic kind. He 
 was the first, however, to introduce the use of the microscope 
 into the Class-room. 
 
 The Irish records of botanical research are at least as 
 scanty as those of Scotland. The first authentic authority 
 on plants was Caleb Threlkeld (1676-1728), but his book, 
 under the ambitious title of " Synopsis Stirpium Hiberni- 
 carum," was little more than a herbal. 
 
 A lectureship was established at Trinity College in 1711 
 and associated with it was a small Physic Garden. In 1786 
 the lecturer, who was at that time Edward Hill, was raised 
 to the status of a professor. His chief work seems to have 
 laid in the botanic garden and in starting the herbarium. 
 Amongst his successors perhaps Professor -William Allman 
 should be mentioned. He was succeeded by a succession 
 of able men, but none of them pre-eminently able. 
 
 This brief survey of the history of British Botany shows 
 that there is ever a steady current of research and investigation 
 going on in these islands and with here and there a temporary 
 
Summary 255 
 
 lull, men of world-wide importance were constantly emerging 
 from the high level of their contemporaries. Hales, no doubt, 
 laid the foundation of scientific plant physiology, even Sachs 
 has said that his " Vegetable Staticks " " was the first com- 
 prehensive work the world had seen which was devoted to 
 the nutrition of plants and the movement of their sap . . . 
 Hales had the art of making plants reveal themselves. By 
 experiments planned and cunningly carried out he forced 
 them to betray the energies hidden in their apparently 
 inactive bodies." Grew was one of the earliest and greatest 
 investigators of plant anatomy, and, as we have said above 
 may be regarded as joint founder with Malpighi of the science 
 of vegetable anatomy. Robert Brown was regarded by his 
 contemporaries as the first botanist of his age, and he it was 
 who for the first time took into account the development 
 of plants as well as the structure of the mature and adult 
 forms. He and John Lindley did much to establish a 
 natural system based on the widest investigation possible 
 in their times. Sir Joseph Hooker may almost be said to 
 be the inventor of phyto-geography. Professor Bower writes 
 of him : " and so we have followed . . . this great man 
 into the various lines of scientific activity which he pursued. 
 We have seen him excel in them all. The cumulative result 
 is that he is universally held to have been, during several 
 decades, the most distinguished botanist of this time. He 
 was before all things a philosopher. In him we see the 
 foremost student of the broader aspects of plant-life at the 
 time when evolutionary belief was nascent." 
 
 In the Stewarts' time, as we have seen, British science 
 led the world, and ever since our men of science have held 
 their own in comparison with the men of science of the 
 nations which can boast of an old civilization and far 
 surpassed, both in amount and in originality, that of nations 
 whose civilization only dates back to a few hundred years. 
 
256 Britaiirs Heritage of Science 
 
 CHAPTER X 
 
 ZOOLOGY 
 
 IN 1544 William Turner, the leading naturalist of his 
 time, published his " Avium Praecipuarum quarum apud 
 Plinium et Aristotelem mentio est, brevis et succincta 
 historia," dedicated to Edward Prince of Wales, after- 
 wards Edward VI. Turner had been educated at Pembroke 
 College, Cambridge, where he knew Latimer and learned 
 Greek from Ridley. He travelled much abroad, and became 
 an M.D. of Ferrara and subsequently of Oxford. Later in 
 life he was ordained, and in 1550 he was appointed Dean 
 of Wells, a post he was compelled to quit on the accession 
 of Queen Mary. His business in life was theological con- 
 troversy and he wrote many polemical works, but his 
 pleasure was in natural history. He contributed a letter 
 on British fishes to his friend Conrad Gesner, with whom 
 he had worked at Zurich, and with whom he constantly 
 corresponded. As an example of the zoology available in 
 the Great Eliza's times, we may quote Turner's description 
 of the grouse. 
 
 " Of the Lagopus" from Pliny. 
 
 " The Lagopus is in flavour excellent, its feet shaggy 
 as in a hare have given it this name. Otherwise, it is 
 white, in size as the Columbi; it is not eaten except in 
 the land of which it is a native, since it is not tameable 
 while living, and when killed its flesh soon putrefies. 
 There is another bird of the same name, differing but 
 in size from the Coturnices, most excellent for food with 
 yellow saffron sauce. Of this Martial makes mention 
 in the following verse : 
 
 "If my Flaccus delights in the eared Lagopodes." 
 
W. Turner, E. Wotton, John Gains 257 
 
 Although this may seem to indicate that Turner was a 
 mere translator and compiler, this is not the case. As 
 Mr. A. H. Evans tells us : 
 
 " While attempting to determine the principal kinds 
 
 of birds named by Aristotle and Pliny, he has added 
 
 notes from his own experience on some species which had 
 
 come under his observation, and in so doing he has 
 
 produced the first book on Birds which treats them in 
 
 anything like a modern scientific spirit . . . nor is 
 
 it too much to say that almost every page bears witness 
 
 to a personal knowledge of the subject, which would be 
 
 distinctly creditable even to a modern ornithologist." 
 
 A contemporary of Turner's, Edward Wotton (1492- 
 
 1555), born at Oxford and elected a Fellow of Magdalen, 
 
 travelled for several years in Italy. He took his M.D. at 
 
 Padua, and later held high office in the College of Physicians, 
 
 and has been described as " the first English Physician who 
 
 made a systematic study of natural history." His book, 
 
 "De Differ entiis Animalium," published two years before 
 
 Turner's Historia and dedicated to the same patron, acquired 
 
 a European reputation. The copy of this book, a fine folio, 
 
 in the British Museum, is said to be " probably unsurpassed 
 
 in typographical excellence by any contemporary work." 
 
 "De DifFerentiis Animalium" was deservedly praised by 
 
 contemporary writers for its learning and for the elegance 
 
 of its language. 
 
 Dr. Caius (1510-1573), in his terse style, wrote "De 
 Canibus Britannicis libellus," 1570, and this was " drawne 
 into Englishe " under the name " Of Englishe Dogges," by 
 Abraham Fleming in 1576, and published in London. Caius 
 wrote his little book as a contribution to Conrad Gesner's 
 " History of Animals," but owing to Gesner's death it was 
 not incorporated in that work. For, from the sixth year of 
 Henry the Eighth until the death of Queen Elizabeth, all 
 the learned men of Europe who were interested in Nature 
 turned to Gesner, the incomparable naturalist of Zurich 
 (1516-1565), amongst whose many works of great import- 
 ance the stupendous " Historia Animalium " is perhaps the 
 most remarkable. 
 
 In the year 1607, Edward Topsell, a member of Christ's 
 
 8 
 
258 Britain's Heritage of Science 
 
 College and, in the matter of livings, somewhat of a pluralist, 
 published, under the title " The Historie of Foure-Footed 
 Beastes," an abstract of Gesner, and in the next year followed 
 it up with " The Historie of Serpents," both illustrated with 
 charmingly quaint, if inaccurate, woodcuts. Topsell had, 
 what the modern zoologist must have (but the possession 
 in his time was less common), a sound knowledge of 
 German, and to this knowledge his books owe much. 
 These works give us a fair idea of what the educated in those 
 days knew of zoology in all its aspects, and that these aspects 
 covered a far wider area than, with the present expansion 
 of knowledge, we can now contemplate under this single 
 science, is shown by the title-page to TopselTs magnificent 
 quarto volume : 
 
 " The History of Foure-Footed Beastes. Describing 
 
 the true and lively figure of every Beast, with a discourse 
 
 of their severall Names, Conditions, Kindes, Vertues (both 
 
 naturall and medicinall), Countries of their breed, their 
 
 love and hate to Mankinde, and the wonderful worke of 
 
 God in their Creation, Preservation, and Destruction. 
 
 Necessary for all Divines and Students, because the 
 
 story of every Beast is amplified with Narrations out 
 
 of Scriptures, Fathers, Phylosophers, Physitians, and 
 
 Poets : wherein are declared divers Hyerogliphicks, 
 
 Emblems, Epigrams, and other ,good Histories, collected 
 
 out of all the Volumes of Conradus Gesner, and all other 
 
 Writers to this present day. By Edward Topsell. 
 
 London, Printed by William Jaggard, 1607." 
 
 Falconry also played a part in the Zoology of the later 
 
 Tudor times. During the reign of Queen Elizabeth this 
 
 sport was " much esteemed and exercised." People of all 
 
 classes eagerly took part in it. To quote Mr. Harting : 
 
 " The rank of the owner was indicated by the species 
 of bird which he carried. To a king belonged the ger- 
 falcon; to a prince, the falcon gentle; to an earl, the 
 peregrine; to a lady, the merlin; to a young squire, 
 the hobby ; while a yeoman carried a goshawk ; a priest, 
 a sparrowhawk; and a knave, or servant, a kestrel." 
 The sport was, however, expensive, for it took much 
 time and devotion to train the birds. The falcon, in those 
 
E, Topsell, F. Willughby, J. Ray 259 
 
 times, as the flying machine is in ours, was in the air, and 
 just as one now hears our undergraduates discussing carbu- 
 retters, air-locks, sparking-plugs, and various vintages of 
 petrol, so in the times of Queen Elizabeth, the keen young 
 men of Shakepeare's Plays discussed the various kinds of 
 hawks and their habits. 
 
 In our last chapter we have sketched the contribu- 
 tions which Ray had made to the science of Botany ; but 
 he has further claims on our regard. He and Francis 
 Willughby, both of Trinity College, Cambridge, attacked 
 similar problems in the animal kingdom. Wiilughby was 
 the only son of wealthy and titled parents, while Ray was 
 the son of a village blacksmith. But the older universities 
 are great levellers, and Ray succeeded in infusing into his 
 fellow student at Cambridge his own genuine love for 
 natural history. With Willughby, he started forth on his 
 methodical investigations of animals and plants in all the 
 accessible parts of the world. Willughby died young and 
 bequeathed a small benefaction and his manuscripts to his 
 older friend. After his death, Ray undertook to revise and 
 complete his " Ornithology," and therein paid great attention 
 to the internal anatomy, to the habits and to the eggs of 
 most of the birds he described. Further, he edited Willughby 's 
 "History of Fishes," but perpetuated the mistake of his 
 predecessors in retaining whales in that group. In rather 
 rationalistic mood, he argues that the fish which swallowed 
 Jonah must have been a shark. Perhaps the weakest of 
 their three great histories "The History of Insects" was 
 such owing to the fact that Ray edited it in his old age. The 
 Ray Society for the publication of works on Natural Science 
 was founded in his honour in 1842. 
 
 Robert Hooke, a Westminster boy and, later, a student 
 at Christ Church, was at once instructor and assistant to 
 Boyle. The year that the Royal Society received their 
 charter, they appointed Hooke curator, and his duty was 
 " to furnish the Society " every day they met with three or 
 four considerable experiments. This formidable task he 
 fulfilled in spite of the fact that " the fabrication of instru- 
 ments for experiments was not commonly known to work- 
 men," and that he never received " above 50 a year and 
 
 K 2 
 
260 Britain's Heritage of Science 
 
 that not certain." Hookewas a man of amazing versatility, 
 very self-confident, attacking problems in all branches of 
 science, greatly aiding their advance, but avid of fame. 
 
 " In person but despicable, being crooked and low in 
 
 stature, and as he grew older more and more deformed. 
 
 He was always very pale and lean and latterly nothing 
 
 but skin and bone." 
 
 His book " Micrographia " is the record of what a modern 
 schoolboy newly introduced to the microscope would write 
 down. Yet he was undoubtedly, although not a lovable 
 character, the best " mechanic of his age." 1 (See also p. 55.) 
 
 John Tradescant ( ? ?1637) is by some believed to have 
 
 been a Dutchman, but his name is an English name, and he 
 seems from an early age to have owned land in Essex, a most 
 English county. One of his earliest works was entitled : 
 " A voiag of ambasad ondertaken by the Right honourabl 
 Sr Dudlie Digges in the year 1618," which is a narrative of 
 a voyage round the North Cape to Archangel, where they 
 arrived at the neighbouring monastery of St. Nicholas on 
 the 16th July 1618, when Tradescant immediately began 
 botanizing, collecting, and ultimately sending a number of 
 northern plants to various friends abroad and making notes 
 upon some twenty -four wild species. This was the first 
 account published of the plants of Russia. In 1620 he 
 voyaged south instead of north, having joined the expedi- 
 tion of Mansell and Sir Samuel Argall against the Corsairs 
 of Algiers, and amongst other rarities brought back by him 
 was the Algerian apricot. In 1625 he was in the service of 
 the Duke of Buckingham, and writes to an agent in Virginia 
 that it was the Duke's wish that he should " deal with all 
 merchants from all places, but especially from Virginia, 
 Bermudas, Newfoundland, Guinea, Binney, the Amazon, 
 and the East Indies, for all manner of rare beasts, fowls, 
 and birds, shells, furs, and stones." On the death of the 
 Duke, Tradescant became gardener to the King and Queen, 
 and it is suggested that it was about this time that he 
 established his physic garden and museum at South Lam- 
 beth. The physic garden was one of the first established 
 in our kingdom, and Pulteney recalls that Tradescant 
 
 1 Waller's " Life of Hooke," 1705. 
 
The Tradescants 261 
 
 was the first who brought together any considerable collec- 
 tion of subjects of natural history. His name is immor- 
 talised in the genus Tradescantia, a spider- wort which he 
 had introduced from Virginia. Parkinson, in his " Paradisus 
 terrestris," speaks of the elder Tradescant as " a painful 
 industrial searcher and lover of all nature's varieties," and 
 having " wonderfully laboured to obtain all the rarest fruits 
 he can hear of in any place of Christendom, Turkey, yea, 
 or the whole world." 
 
 His only child, John Tradescant (1608-1662), was born 
 at Meopham, Kent, and apparently succeeded his father as 
 gardener to Queen Henrietta Maria. In 1637, the younger 
 Tradescant was in Virginia gathering all varieties of ferns, 
 plants, and shells for the museum at Lambeth, and in 1656 
 he published his " Museum Tradescantianum : or collection 
 of rareties preserved in South Lambeth, near London." In 
 this task he was assisted by his friend Ashmole, and the 
 book, which runs into 179 pages, contains lists of birds, 
 mammals, fish, shells, insects, minerals, war instruments, 
 utensils, coins, and medals. It is interesting to note that 
 he had a complete " dodar " from the island of Mauritius. 
 This was the celebrated stuffed dodo of which the head and 
 foot are still preserved at Oxford. The complete body had 
 been studied by Willughby and Ray. On the 12th December 
 1659, Ashmole notes in his diary that " Mr. Tradescant and 
 his wife told me they had been long considering upon whom 
 to bestow their Closet of Curiosities when they died, and at 
 last had resolved to give it unto me." Ashmole had built 
 himself a large brick house near Lambeth adjoining that 
 which had been Tradescant's, and shortly after its comple- 
 tion removed the collection to his new house, and in 1677 
 he announced his intention of giving his collection to the 
 University of Oxford, on condition that a suitable building 
 be built to receive it. This was erected from the design of 
 Sir Christopher Wren, and the collections were transferred 
 to Oxford in 1683, when the name of Tradescant was rather 
 unjustly sunk in that of Ashmole. 
 
 There was a lull in Zoological Science during the 
 eighteenth century in our islands, and only the names of 
 one or two outstanding zoologists appear. That of Thomas 
 
262 Britain's Heritage of Science 
 
 Pennant (1726-1798) must not, however, be forgotten. In 
 his boyhood he received a copy of Francis Willughby's 
 " Ornithology," and to that he attributed his interest in 
 natural history. He was for a time an undergraduate at 
 Queen's College, Oxford, but did not proceed to a degree. 
 Shortly after leaving Oxford he travelled through Cornwall 
 and studied the minerals and fossils of the county, and in 
 1754 he travelled in Ireland, but here he kept a very imper- 
 fect diary, " such," he adds, " was the conviviality of the 
 country." In 1765 we find him visiting France and staying 
 with Buffon. He also visited Voltaire at Ferney. whom he 
 found " very entertaining and a master of English oaths " ; 
 on his return journey at the Hague he met the celebrated 
 Pallas. The first part of his " British Zoology " appeared 
 in 1766, and his " Synopsis of Quadrupeds " five years later. 
 
 At various times in his life, Pennant thoroughly 
 explored much of the British Islands, and made copious 
 notes on the fauna, especially on the birds of the coast. In 
 1781 he published " A History of Quadrupeds," which was 
 a new and enlarged edition of his " Synopsis," and three 
 years later his " Arctic Zoology " appeared. Arctic explora- 
 tion has always fascinated our British naturalists. 
 
 Pennant certainly occupies a leading position amongst 
 the zoologists of the eighteenth century, and although he 
 did not reach such a high standard as Buffon, he was a 
 really learned man, and he had an undoubted faculty for 
 making dry and obscure things readable and plain. 
 
 Although, as we have said above, British zoology suffered 
 under a lull during the eighteenth century, the two Hunters, 
 William and John, helped with Pennant to keep the sacred 
 flame alight. 
 
 William Hunter (1718-1783) was born in Lanarkshire 
 and educated at Glasgow University. He first came to 
 London as dissector to Dr. James Douglas, whose son he 
 tutored, and with him he travelled on the Continent. 
 Later, he was remarkably successful as a lecturer, being 
 eloquent, competent, and capable of illustrating his dis- 
 courses with practical dissections. His success as an 
 obstetric surgeon was great, and he was appointed Physician 
 Extraordinary to Queen Charlotte in 1764. 
 
Thomas Pennant, The Hunters 263 
 
 During his comparatively long life he had accumulated 
 a notable collection of anatomical and pathological speci- 
 mens, and in 1765 he proposed to build a museum to house 
 them, and to spend several thousands of pounds on the 
 building, in addition to which he was prepared to endow 
 a professorship. The offer which he had made to the 
 Government, however, fell through, and subsequently he 
 undertook, at his own expense, to carry out the project 
 without Government aid, and he built his well-known 
 institution in Great Windmill Street. By 1783 he reckoned 
 that his collections had cost him over 20,000. 
 
 Unfortunately he and his brother John quarrelled, or 
 at least differed, the cause being that William claimed the 
 credit of more than one discovery which John seems to 
 have made. His collections, which by the time of his death 
 included minerals, shells, corals, coins, rare manuscripts 
 and books, together with his great obstetrical collection, 
 were ultimately left to the University of Glasgow. William 
 Hunter's claim to a place in these pages is that he was both 
 a great collector, a great investigator, and a great teacher. 
 
 His younger brother, John Hunter (1728-1793), came to 
 London in 1748 to assist William, and soon showed a real 
 genius for anatomy. He became a " Master of Anatomy " 
 of the Surgeons' Corporation and a pupil at St. George's 
 Hospital, where for a time he was house surgeon. Also he 
 resided for some terms at Oxford, where, he says, " they 
 wanted to make an old woman of me, or that I should stuff 
 Latin and Greek at the University, but," he added signifi- 
 cantly, pressing his thumb on the table, " these schemes I 
 cracked like so many vermin as they came before me." 
 
 John was more of an investigator than William, but a 
 far less able teacher. He traced the descent of the testis 
 in the foetus, as Aristotle is said to have done before him, 
 he investigated the placental nerves, studied the nature of 
 pus, investigated the absorbing power of veins, and in con- 
 junction with his brother endeavoured to determine the 
 course and function of the lymphatics. 
 
 After abandoning his partnership with William he served 
 abroad with the British Army in Portugal and elsewhere, 
 and became a great authority on gun-shot wounds. On 
 
264 Britain's Heritage of Science 
 
 returning to London in 1763, he began to practise as a 
 surgeon in Golden Square, and here he first started on his 
 famous collections. The menagerie at the Tower and other 
 private zoological gardens served him with material, and he 
 spared neither time nor money to add to his museum. In 
 1764 he built himself a house at Earl's Court, Kensington, 
 which was properly fitted for macerating, injecting, and 
 dissecting the bodies of animals, and was also provided 
 with cages for keeping them alive. His sympathy was in 
 no way confined to the vertebrates, for he had ponds in 
 which he tried artificially to produce pearls in oysters, and 
 he was very fond of bees, though in truth his real passion 
 was for the fiercer kind of carnivora. 
 
 John Hunter helped a number of men who have left 
 their mark in the medical profession. Perhaps the most dis- 
 tinguished of these was Edward Jenner, but Astley Cooper, 
 John Abernethy, Henry Cline, James McCartney were also 
 of the company. In 1783 he built a large museum, with 
 lecture-rooms, in Leicester Square, and about this time he 
 made his well-known discovery on the collateral circulation 
 by anastomosing branches of blood-vessels. 
 
 In character he seems to have been impatient and rather 
 rough, incapable of readily expounding the information that 
 he had acquired information that was mostly from direct 
 observation, for he read but little. He was a strong Tory, 
 and it is stated that he would rather have seen his museum 
 burning than show it to a democrat. Hunter stood at the 
 head of British surgery, but he was more than a surgeon, 
 he was an all-round anatomist, with wide and scientific 
 views as to what life meant. His claim to appear in these 
 pages is that he was also a great comparative anatomist, 
 though his zoology was always secondary to his surgery. 
 By his will his museum was offered to the British Govern- 
 ment on reasonable terms, and in case they refused it was 
 to be sold to some foreign State or put up to auction. 
 National finance in 1793 was, however, at a low ebb, and 
 Mr. Pitt showed no eagerness to complete the purchase. 
 Six years later the Government recommended the collection 
 should be bought for 15,000, knowing well that it was 
 worth a great deal more. However, the purchase was 
 
John Hunter, Richard Owen 265 
 
 completed and the collection was offered to the Royal 
 College of Physicians. On their refusal to accept it, it was 
 offered to and accepted by the Corporation of Surgeons, 
 which next year became the Royal College of Surgeons, 
 and from 1806 the Hunterian Collection has been housed 
 in Lincoln's Inn Fields. At the present time this original 
 nucleus of the College museum comprises one-fifth of the 
 specimens therein exhibited. 
 
 The most dominant zoologist in the first half of the 
 nineteenth century was Sir Richard Owen (1804-1892), who 
 was born at Lancaster and was educated at the grammar 
 school of that town with William Whewell, the author of 
 the " History of the Inductive Sciences." When he was 
 sixteen he was apprenticed to a surgeon, and here his love 
 of anatomy at once found scope. Later he matriculated 
 at Edinburgh, and attended the extra-mural course of 
 lectures on anatomy given by Dr. John Barclay, who, as 
 Owen himself testified, has an " extensive knowledge of 
 vertebrate anatomy." In the spring of 1835 he joined 
 St. Bartholomew's Hospital, London, having passed the 
 examination of the Royal College of Surgeons, and later 
 set up in private practice near Lincoln's Inn Fields. He 
 became lecturer on Comparative Anatomy at his hospital in 
 1827, and after a short interval he was appointed Assistant 
 Conservator of the Hunterian Museum of the Royal College 
 of Surgeons. The Conservator was then William Clift, who 
 had done so much to preserve Hunter's Museum in the 
 long interval between his death and its transference to 
 the Royal College of Surgeons. In 1831 Cuvier invited 
 Owen to Paris, where he attended Cuvier's and Geoffroy 
 St. Hilaire's lectures in the Jardin des Plantes. 
 
 Owen was well known as a writer of monographs on 
 many rare animals, and the first of these was his memoir 
 on the " Pearly Nautilus," which placed him, as Huxley 
 says, " in the front rank of anatomical monographers." 
 In the early forties, he succeeded Clift, whose daughter 
 he had married, as Conservator to the Royal College of 
 Surgeons. But before this, in 1836, he had been made the 
 first Hunterian Professor of Comparative Anatomy at the 
 College, which involved the annual delivery of twenty-four 
 
266 Britain's Heritage of Science 
 
 lectures, and these he continued to give for a period of 
 twenty years. 
 
 Owing to the influence of the Prince Consort, the 
 British Court was, in Owen's time, more interested in 
 science than it has been since his death, and Owen became 
 of considerable influence in court and in society circles. 
 In 1845 he was elected a member of that exclusive body 
 " The Club," founded by Dr. Johnson. In 1852 the Queen 
 
 five him the cottage called Sheen Lodge, in Richmond 
 ark, where he lived for forty years. 
 
 There seems little doubt that in the middle of the last 
 century Owen was recognized throughout the world as the 
 first anatomist of his day; but his position at the College 
 of Surgeons was at this time becoming difficult. Friction 
 arose between him and the Governing Body, and in 1856 
 he readily accepted the offer made to him by the Trustees 
 of the British Museum to undertake the newly created post 
 of Superintendent of the Natural History Department in 
 the Museum. This post he held until 1884. He added 
 greatly to our knowledge of animal structure by his success- 
 ful dissection of many rare forms, such as the Pearly 
 Nautilus, Limulus, Lingula, Apteryx, and others, and, follow- 
 ing on the lines of Cuvier, he was particularly successful in 
 reconstructing extinct vertebrates. Another considerable 
 advance he made in science was his introduction of the 
 terms " homologous " and " analogous." 
 
 The accommodation afforded by the Museum at Blooms- 
 bury for Natural History specimens was totally inadequate, 
 and as early as 1859 Owen submitted a report to the Trustees 
 setting forth his views as to the proper housing of the 
 National collections. After the usual delays attendant upon 
 all Government action, land was purchased at South 
 Kensington, on which ten years later the present buildings 
 rose. They were opened to the public in 1881. Owen failed, 
 however, to achieve many of his desires. A lecture theatre, 
 such as exists in the Metropolitan Museum of Natural 
 History in New York, is even now still lacking, and, he 
 adds, " no collection of zoological specimens can be regarded 
 as complete without a gallery of physical ethnology.'' This 
 also is still wanting. A third of his wishes, a gallery of 
 
Richard Owen, Charles Darwin 267 
 
 Cetacean skeletons, was only achieved under his successor, 
 Sir William Flower. The fact was, as Sir William pointed 
 out, that the division of the Museum into four departments, 
 each with its own head, left Owen practically powerless. 
 Increased age added to the difficulties, and in 1883 he 
 resigned his post and spent the remaining nine years of his 
 life in retirement in his beautiful cottage at Sheen Lodge. 
 
 Owen was widely read, fond of music and the drama, 
 and a man of striking personality. But, owing to his 
 faculty for acrimonious controversy, he was rather an 
 isolated zoologist, standing alone and going his own way. 
 His power of work was prodigious : not only did he pub- 
 lish innumerable papers in all the scientific journals, but a 
 large number of books, the titles of which are set forth in 
 the " Dictionary of National Biography." 
 
 On the same day, the 12th February 1809, upon which 
 Abraham Lincoln first saw the light, was born, at the 
 " Mount," Shrewsbury, a little child destined as he grew 
 up to alter our conceptions of organic life perhaps more 
 profoundly than any other man has ever altered them, 
 and this not only in the subjects he made his own, but in 
 every department of human knowledge and thought. 
 
 As to the man, two estimates of his character may 
 be quoted, one by a student who lived on terms of close 
 intimacy with Darwin when at Christ's College, Cambridge, 
 the other the considered judgment of one who knew and 
 loved and fought for Darwin in later life. 
 Mr. Herbert says : 
 
 " It would be idle for me to speak of his vast 
 intellectual powers . . . but I cannot end this 
 cursory and rambling sketch without testifying, and I 
 doubt not all his surviving college friends would concur 
 with me, that he was the most genial, warm-hearted, 
 generous, and affectionate of friends ; that his sympathies 
 were with all that was good and true; and that he had 
 a cordial hatred for everything false, or vile, or cruel, 
 or mean, or dishonourable. He was not only great, but 
 pre-eminently good, and just, and lovable." 
 Professor Huxley, speaking of the name of Darwin, says : 
 " They think of him who bore it as a rare combination 
 
268 Britain's Heritage of Science 
 
 of genius, industry, and unswerving veracity, who earned 
 his place among the most famous men of the age by sheer 
 native power, in the teeth of a gale of popular prejudice, 
 and uncheered by a sign of favour or appreciation from 
 the official fountains of honour; as one who, in spite of 
 an acute sensitiveness to praise and blame, and notwith- 
 standing provocations which might have excused any 
 outbreak, kept himself clear of all envy, hatred, malice, 
 nor dealt otherwise than fairly and justly with the 
 unfairness and injustice which was showered upon him; 
 while, to the end of his days, he was ready to listen 
 with patience and respect to the most insignificant of 
 reasonable objectors." 
 
 Although the Darwin family trace their ancestry to about 
 the year 1500, we need not, here, go further back than 
 Charles's grandfather, Erasmus (1731-1802). This distin- 
 guished physician, the author of the " Loves of the Plants " 
 and of " Zoonomia," transmitted to his grandson his bene- 
 volent and sympathetic character and a remarkable charm 
 of manner, as well as his great stature. 
 
 In many respects Erasmus Darwin was in advance of 
 his times. He was, for instance, a great advocate of temper- 
 ance, and Mr. Lucas has lately reminded us of his inhuman 
 advice : " If you must drink wine, let it be home-made," 
 surely the shortest cut to total abstinence yet devised by 
 the wit of man. 
 
 He wrote innumerable verses in the somewhat stilted 
 style of the period. They were immensely admired by his 
 contemporaries, and Cowper, who could have had little or 
 no sympathy with most of Darwin's views, wrote in 
 conjunction with Halley a poem in his honour which 
 begins : 
 
 " No envy mingles with our praise, 
 
 Tho' could our hearts repine 
 At any poet's happier lays, 
 
 They would, they must, be thine." 
 
 The third son of Erasmus, Robert Waring Darwin, was 
 the father of Charles. Like his father, he was a physician, 
 and for many years he enjoyed a large practice at Shrewsbury. 
 He married Susannah, the daughter of his father's friend, 
 
Charles Darwin 
 
 From a photograph by 
 
Erasmus Darwin, Charles Darwin 269 
 
 Josiah Wedgwood, of the well-known pottery works at 
 Etruria, Staffordshire. 
 
 In his charming and frank fragments of autobiography 
 Darwin recalls many incidents of his own childhood. As 
 a boy he early developed a taste for collecting plants, shells, 
 minerals and other natural objects, and he was at pains to 
 learn their names. He tells a curious story of himself 
 pretending that he could alter the colour of flowers by 
 watering them with coloured fluids, curious because at his 
 age boys are not as a rule interested in such problems 
 of vegetable physiology. It is characteristic that in the 
 earliest portrait of him, a charming crayon sketch in which 
 his youngest sister Catherine also appears, he is depicted 
 holding a pot of flowers in his hands. At the age of nine 
 he was sent to the school at Shrewsbury, then in its picturesque 
 old buildings in the town ; he was a boarder there, and thus 
 had, as he says, "the great advantage of living the life of a 
 true schoolboy." He remained at school until he was sixteen, 
 and then his father, thinking he was not doing much good, 
 sent him to join his elder brother, who was studying medicine 
 at Edinburgh University. At this period, like his grand- 
 father, his father and his brother, Darwin was destined to 
 study medicine, and he attended the medical course, which 
 consisted entirely of lectures, all of them, with but one 
 exception, " intolerably dull." Apart from the lectures, 
 which were evidently almost useless, Darwin acquired a 
 good deal of miscellaneous information whilst at Edinburgh ; 
 he did much collecting along the shore, learnt the art of the 
 bird-stuffer, frequented two or three societies, and doubt- 
 less, as is the habit of those of his age, took part in many 
 and interminable discussions. He also became an ardent 
 sportsman and was especially enthusiastic about shooting. 
 Apparently, however, his heart was not in his medical 
 work, and in 1827 his father proposed that he should become 
 a clergyman, and with this in view decided to send him to 
 Cambridge. 
 
 The Admission Book at Christ's College contains the 
 following entry : 
 
 " Admissi sunt in Collegium Christi a Festo Divi 
 
 Michaelis 1827 ad Fes um eiusdem 1828 : 
 
270 Britain's Heritage of Science 
 
 [No. 3.] 
 
 Octobris 15. Carolus Darwin admissus est pensionarius 
 
 minor sub Mro Shaw." 
 
 Charles Darwin came into residence in the Lent Term 
 of 1828. 
 
 Late in life men are apt to look back upon their College 
 days with a somewhat exaggerated regret for lost oppor- 
 tunities, and Charles Darwin felt that at Cambridge his 
 " time was wasted, as far as his academical studies were 
 concerned, as completely as at Edinburgh and at school." 
 But this must not be taken too literally. He seems to have 
 passed his University examinations with ease, and a letter 
 recording his joy at getting through the " Little-Go " shows 
 that he at any rate took them seriously. 
 
 Apparently Darwin's experiences at Edinburgh had given 
 him a distaste for lectures, and it is unfortunate that this 
 distaste kept him away from the teaching of Sedgwick. He 
 attended, however, the botanical lectures of Henslow, which 
 were then crowded with students as well as with senior 
 members of the University, and he revelled in the excursions 
 which Henslow used to conduct, on foot or in coaches, or 
 down the river in barges, "or to some more distant place, 
 as to Gamlingay, to see the wild lily of the valley and to 
 catch on the heath the rare natterjack." He was, in fact, 
 known to the senior members of the University as " the 
 man who walks with Henslow," and the man who walked 
 with Henslow did not spend three years at Cambridge wholly 
 in vain. 
 
 Amongst other absorbing pursuits was that of collecting 
 insects, especially beetles. He was first interested in ento- 
 mology by his cousin, W. Darwin Fox, of Christ's, who 
 had kindred tastes and with whom he frequently corre- 
 sponded in fact, most of the letters written from Christ's 
 College that remain were addressed to him. 
 
 Darwin received his degree on April 26, 1831, and it was 
 during this term and the subsequent Easter term, when he 
 was still in residence, that Henslow persuaded him to begin 
 the study of geology. There must have been something 
 unusual about Darwin, for he seems to have made friends 
 with men much older than himself, and some of them, one 
 
Charles Darwin 271 
 
 would imagine, not very approachable. He records how 
 he used to walk home at night with Dr. Whewell; and 
 rejoices in his friendship with Leonard Jenyns. He became 
 the friend of Adam Sedgwick, and in August 1831 he 
 accompanied him on a geological survey in North Wales. 
 It was on returning from this trip that he found a letter 
 from Henslow informing him that Captain Fitzroy was 
 willing to give up part of his cabin to any young man who 
 would volunteer without pay to act as naturalist on the 
 classical voyage of the Beagle. Captain Fitzroy was going 
 out to survey the southern coast of Tierra del Fuego and 
 to visit some of the South Sea Islands, returning by the 
 Indian Archipelago. 
 
 Captain Fitzroy, like Mrs. R. Wilfer, was a " disciple 
 of Lavater," and took exception to the shape of Darwin's 
 nose. " He doubted whether any one with my nose could 
 possess sufficient energy and determination for the voyage." 
 But on acquaintance his doubts soon vanished, and the 
 captain and his naturalist became close friends. 
 
 Space forbids any account of the voyage of the Beagle. 
 As far as Darwin is concerned, it took place at what is, 
 perhaps, the period of life when the mind is most original. 
 Many of the great creative ideas of thought appear to be 
 engendered between the age of twenty and thirty years, 
 and although much may be added later, the foundation of 
 man's life work is usually laid then. Darwin, as he records, 
 " worked to the utmost during the voyage from the mere 
 pleasure of investigation and from " his " strong desire to 
 add a few facts to the great mass of facts in Natural Science." 
 
 He returned to England in October 1836, and two months 
 later, on December 13, Darwin settled again in Cambridge, 
 but only for three months. 
 
 Whatever feeling Darwin had about the education that 
 he received at Cambridge, he had a real love for the place, 
 to which he sent all but one of his sons; and it is good to 
 read the following lines in his autobiography : " Upon the 
 whole, the three years I spent at Cambridge were the most 
 joyful of my happy life." 
 
 Early in the year 1839 Darwin married his cousin, Emma 
 Wedgwood, and for nearly four years they kept house in 
 
272 Britain's Heritage of Science 
 
 Upper Gower Street. The sustained toil and the discomforts 
 of the voyage had injured Darwin's health, and he and his 
 wife led a life of " extreme quietness." During this period, 
 he states, " I did less scientific work, though I worked as 
 hard as I possibly could, than during any other equal length 
 of time in my life. This was owing to frequently recurring 
 unwellness and to one long and serious illness." His health, 
 indeed, prevented his regular attendance at scientific and 
 other gatherings which are among the few attractions London 
 can offer over the country, and in 1842 he removed to the 
 secluded Kentish village of Down. The chief attraction of 
 the place was its quietness, " its chief merit," as Darwin 
 writes, " is its extreme rurality." The house stands a 
 quarter of a mile from the village, whose peaceful charm 
 has been but little altered in the last sixty-seven years. 
 And here it was he says : "I can remember the very spot, 
 whilst in my carriage, when to my joy the solution occurred 
 to me." The " solution " was " natural selection by means 
 of the survival of the fittest." 
 
 Here for forty years Darwin lived and laboured, in spite 
 of ill-health which often laid him aside for weeks, his daily 
 task always confined to very few hours of work. We need 
 not follow further the details of this happy life, but one 
 event, and that a well-known one, may briefly be referred 
 to. Darwin's work was so catholic, its bulk so great and 
 its effect so stimulating, that few have realised how vast 
 was the output of scientific work which, though often an 
 invalid, he gave to the world. The extent of the work has 
 been perhaps a little overshadowed by the immense import- 
 ance of that great generalization known as Natural Selection. 
 Sir Wm. Thiselton-Dyer has reminded us that Darwin lies 
 beside Newton in Westminster Abbey, and he adds : "It 
 is the singular fortune of an illustrious University that of 
 two of her sons, one should have introduced a rational order 
 into the organic and the other into the inorganic world." 
 
 In 1908 was celebrated the Jubilee of the reading of a 
 Paper at the Linnean Society entitled, " On the Tendency 
 of Species to form Varieties; and on the Perpetuation of 
 Varieties and Species by Natural Means of Selection." This 
 was the joint production of Charles Darwin and of Alfred 
 
Charles Darwin, Alfred Wallace 273 
 
 Russell Wallace, and was laid before the Society by Sir 
 Joseph Hooker and Sir Charles Lyell. The history of this 
 Paper is well known, but it is so creditable to both these 
 high-minded and honourable men that I may briefly repeat 
 it, and in doing so I cannot do better than use the noble 
 words 1 of Wallace : 
 
 " The one fact," said Wallace, " that connects me 
 with Darwin, and which, I am happy to say, has never 
 been doubted, is that the idea of what is now termed 
 * natural selection ' or * survival of the fittest,' together 
 with its far-reaching consequences, occurred to us 
 independently, and was first jointly announced before this 
 Society fifty years ago. 
 
 " But what is often forgotten by the press and the 
 public is, that the idea occurred to Darwin in October 
 1838, nearly twenty years earlier than to myself (in 
 February 1855); and that during the whole of that 
 twenty years he had been laboriously collecting evidence 
 from the vast mass of literature of Biology, of Horti- 
 culture, and of Agriculture; as well as himself carrying 
 out ingenious experiments and original observations, 
 the extent of which is indicated by the range of subjects 
 discussed in his * Origin of Species,' and especially in that 
 wonderful store-house of knowledge his ' Animals and 
 Plants under Domestication,' almost the whole materials 
 for which works had been collected, and to a large extent 
 systematized, during that twenty years. 
 
 " So far back as 1844, at a time when I had hardly 
 thought of any serious study of nature, Darwin had 
 written an outline of his views, which he communicated 
 to his friends, Sir Charles Lyell and Dr. (now Sir Joseph) 
 Hooker. The former strongly urged him to publish an 
 abstract of his theory as soon as possible, lest some other 
 person might precede him but he always refused till 
 he had got together the whole of the materials for his 
 intended great work. Then, at last, Lyell 's prediction 
 was fulfilled, and, without any apparent warning, my 
 letter, with the enclosed Essay, came upon him, like a 
 
 1 The Darwin-Wallace Celebration. The Linnean Society, London, 
 1908, pp. 5-7. 
 
 S 
 
274 Britain's Heritage of Science 
 
 thunderbolt from a cloudless sky ! This forced him to what 
 he considered a premature publicity, and his two friends 
 undertook to have our two papers read before this Society. 
 " How different from this long study and preparation 
 this philosophic caution this determination not to 
 make known his fruitful conception till he could back 
 it up by overwhe-lming proofs was my own conduct. 
 The idea came to me, as it had come to Darwin, in a 
 sudden flash of insight : it was thought out in a few 
 hours was written down with such a sketch of its various 
 applications and developments as occurred to me at the 
 moment, then copied on thin letter-paper and sent off 
 to Darwin all within a week. / was then (as often 
 since) the ' young man in a hurry ' : he, the painstaking 
 and patient student, seeking ever the full demonstration 
 of the truth that he had discovered, rather than to achieve 
 immediate personal fame." 
 
 It is a remarkable fact that both naturalists owed their 
 inspiration to the same source. Both had read the " Essay 
 on Population," written by a modest clergyman named 
 Malthus, a book which on its appearance was met with a 
 storm of execration; both saw in it the demonstration of 
 that lt struggle for existence " which surrounds us on all 
 sides, and both and they alone of all the readers of Malthus) 
 saw that the necessary consequence of this struggle for 
 existence was that the fittest alone, survive. This concep- 
 tion, " an essentially new creative thought," as Helmholtz 
 described it, explained the method of that evolution which 
 since the tima of the Greeks has been at the back of man's 
 mind. It thus rendered the fact of evolution acceptable 
 and even inevitable in the minds of all intelligent thinkers 
 and brought about changes in our attitude to the organic 
 world and indeed in our whole relation to life greater, perhaps, 
 than have ever been produced by any previous thought of 
 man. 
 
 There were, of course, many British evolutionists before 
 Darwin, amongst whom may be mentioned Charles Darwin's 
 grandfather, Erasmus Darwin, Wells, Patrick Matthew, 
 Pritchard, Grant, Herbert all these writers advocated, and 
 some even hinted at, natural selection. Above all, Bobert 
 
Natural Selection 275 
 
 Chambers, whose " Vestiges of Creation " remained anonymous 
 until after his death, strongly pressed the view that new 
 species of animals were being evolved from simpler types. 
 
 During the incubatory period of Darwin's great work, as 
 Alfred Newton has remarked, systematists, both in zoology 
 and botany, had been feeling great searchings of heart as 
 to the immutability of species. There was a general feeling 
 in the air that some light on this subject would shortly appear. 
 As a recent writer has reminded us, 
 
 " in studying the history of evolutionary ideas, we 
 must keep in mind two distinct lines of thought, first, 
 the conviction that species are not immutable, and that 
 by some means or other new forms of life are derived 
 from pre-existing ones. Secondly, the conception of some 
 process or processes by which this change of old forms and 
 new ones may be explained." 
 
 Now, as we have seen, the first of these lines of thought 
 had been accepted by many writers. Darwin's great merit 
 was that he conceived a process by means of which this 
 evolution in the organic kingdom could be explained. 
 
 It has been somewhat shallowly said, said in fact on the 
 day of the centenary of Darwin's birth, that " we are upon 
 very unsafe ground when we speculate upon the manner in 
 which organic evolution has proceeded without knowing 
 in the least what was the variable organic basis from which 
 the whole process started." Such statements show a certain 
 misconception, not confined to the layman, as to the scope 
 and limitations of scientific theories in general, and to the 
 theory of organic evolution in particular. The idea that 
 it is fruitless to speculate about the evolution of species 
 without determining the origin of life is based on an erroneous 
 conception of the true nature of scientific thought and of the 
 methods of scientific procedure. For Science, the world of 
 natural phenomena is a complex of procedure going on in 
 time, and the sole function of Natural Science is to construct 
 systematic schemes forming conceptual descriptions of 
 actually observed processes. Of ultimate origins Natural 
 Science has no knowledge and can give no account. The 
 question whether living matter is continuous or not with 
 what we call non-living matter is certainly one to which an 
 
 S 2 
 
276 Britain's Heritage of Science 
 
 attempted answer falls within the scope of scientific method. 
 If, however, the final answer should be in the affirmative 
 we should then know that all matter is living, but we should 
 be no nearer to the attainment of a notion of the origin of 
 life. No body of scientific doctrine succeeds in describing in 
 terms of laws of succession more than some limited set of 
 stages of a natural process ; the whole process if, indeed, it 
 can be regarded as a whole must for ever be beyond the 
 reach of scientific grasp. The earliest stage to which Science 
 has succeeded in tracing back any part of a sequence of 
 phenomena itself constitutes a new problem for Science and 
 that without end. There is always an earlier stage and to an 
 earliest we can never attain. The questions of origins 
 concern the theologian, the metaphysician, perhaps the poet. 
 The fact that Darwin did not concern himself with questions 
 as to the origin of life nor with the apparent discontinuity 
 between living and non-living matter in no way diminishes 
 the value of his work. The broad philosophic mind of the 
 great Master of inductive method saw too fully the nature of 
 the task he had set before him to hamper himself with 
 irrelevant views as to origins. 
 
 No well-instructed person imagines that Darwin spoke 
 either the first or the last word about organic evolution. 
 His ideas as to the precise mode of evolution may be, and 
 are being, modified as time goes on. This is the fate of all 
 scientific theories; none, are stationary, none are final. 
 The development of Science is a continuous process of evolu- 
 tion, like the world of phenomena itself. It has, however, 
 some few landmarks which stand out exceptional and 
 prominent. None of these is greater or will be more enduring 
 in the history of thought than the theory associated with 
 the name of Charles Darwin. 
 
 But in reading his writings and his son's admirable " Life " 
 one attains a very vivid impression ,of the man. One of 
 his dominant characteristics was simplicity simplicity and 
 directness. In his style he was terse, but he managed to 
 write so that even the most abstruse problems became clear 
 to the public. The fascination of the story he had to tell 
 was enhanced by the direct way in which he told it. 
 
 One more characteristic. Darwin's views excited at the 
 
Organic Evolution 277 
 
 time intense opposition and in many quarters intense hatred. 
 They were criticised from every point of view, and seldom 
 has a writer been more violently attacked and abused. Now 
 what seems so wonderful in Darwin was that at any rate 
 as far as we can know he took both criticism and abuse 
 with mild serenity. What he wanted to do was to find the 
 truth, and he carefully considered any criticism, and if it 
 helped him to his goal he thanked the critic and used his 
 new facts. He never wasted time in replying to those who 
 fulminated against him, he passed them by and went on 
 with his search. 
 
 It is a somewhat remarkable fact that whilst the works 
 of Darwin stimulated an immense amount of research in 
 Biology, this research did not at first take the line he 
 himself had traced. With some exceptions, the leading 
 zoological work of the end of the last century took the form 
 of embryology, morphology, and palaeontology; and such 
 subjects as cell-lineage, the minute structure of protoplasm, 
 life-histories, teratology, have occupied the minds of those 
 who interest themselves in the problems of life. Among 
 all these lines of research man has been seeking for the 
 solution of that secret of nature which at the bottom of his 
 heart he knows he will never find, and yet the pursuit of 
 which is his one abiding interest. Had Francis Balfour 
 lived we should, probably, have sooner returned to the broader 
 lines of research as practised by Darwin, for it was Balfour's 
 intention to turn himself to the physiology using the term 
 in its widest sense of the lower animals. Towards the 
 end of the nineteenth century, stimulated by Galton, Weldon 
 began those series of measurements and observations which 
 have culminated in the establishment of a great school of 
 Eugenics and Statistics in London. With the beginning of 
 the twentieth century came the rediscovery of the neglected 
 facts recorded by Gregor Mendel, Abbot of Brunn, some 
 years before, and with that rediscovery an immediate and 
 enormous outburst of enthusiasm and of work. Mendel 
 had placed a new instrument in the hand of the breeder, 
 an instrument which, when he has learnt to use it, may give 
 him a power over all domesticated animals and cultivated 
 crops undreamt of before. We are getting a new insight 
 
278 Britain's Heritage of Science 
 
 into the workings of Heredity and we are acquiring a new 
 conception of the individual. The few years which have 
 elapsed since men's attention was redirected to the principles 
 first enunciated by the Abbot of Brunn have seen a School 
 of Genetics arise at Cambridge, and an immense amount of 
 practical experiment on inheritance has also been done in 
 France, Holland, Austria, and especially in the United States. 
 As the work has advanced new ideas have arisen and earlier 
 formed ideas have had to be abandoned; this must be so 
 with every advancing science. But it has now become 
 clear at any rate to some competent authorities that 
 mutations occur, and occur especially in cultivated species; 
 and that these mutations may breed true seems now to 
 be established. In wild species also they apparently occur, 
 but whether they are as common in wild as in cultivated 
 species remains to be seen. If they are not, in my opinion, 
 a most profitable line of research would be to endeavour to 
 determine what factor exists in cultivation which stimulates 
 mutation. 
 
 To what extent Darwin's writings would have been 
 modified had Mendel's work come into his hands we can 
 never know. He carefully considered the question of 
 mutation, or as they called it then, saltation, and as time 
 went on, he attached less and less importance to these 
 variations as factors in the origin of species. Ray Lan- 
 kester has recently reminded us that Darwin's disciple and 
 expounder, Huxley, " clung to a little heresy of his own as 
 to the occurrence of evolution by saltatory variation," and 
 there must have been frequent and prolonged discussion on 
 the point. That " little heresy " has now become the ortho- 
 doxy of a number of eager and thoughtful workers who have 
 been at times rather aggressive in their attacks on the 
 supporters of the old creed. 
 
 The publication of " The Origin of Species " naturally 
 aroused immense opposition and heated controversy. But 
 Darwin, as we have said, was no controversialist. Huxley 
 wrote shortly after his death : 
 
 " None have fought better, and none have been more 
 
 fortunate, than Charles Darwin. He found a great truth 
 
 trodden underfoot, reviled by bigots, and ridiculed by all 
 
G. Mendel, C. Lyell, T. Huxley 279 
 
 the world ; he lived long enough to see it, chiefly by his 
 own efforts, irrefragably established in science, insepar- 
 ably incorporated with the common thoughts of men, 
 and only hated and feared by those who would revile, 
 but dare not. What shall a man desire more than this ?" 
 Darwin, also, was fortunate in his supporters, though some 
 of the leading biologists of the time conspicuous among 
 them was Owen rejected the new doctrine. In Hooker, 
 on the botanical side, in Huxley, on the zoological side, and 
 in Lyell, on the geological side, he found three of the ablest 
 intellects of his country and of his century as champions. 
 None of these agreed on all points with their leader, but 
 they gave more than general adherence to his principles, 
 and a more than generous aid in promulgating his doctrine. 
 Lyall was an older man, and his " Principles of Geology " 
 had long been a classic. This book inspired students who 
 became leaders in the revolution of thought which was 
 taking place in the last half of the nineteenth century. One 
 of these writes : 
 
 " Were I to assert that if the * Principles of Geology ' 
 had not been written, we should never have had * The 
 Origin of Species,' I should not be going too far : at all 
 events, I can safely assert, from several conversations 
 I had with Darwin, that he would have most unhesi- 
 tatingly agreed to that opinion." x 
 
 Sir Joseph Hooker, whose great experience as a traveller 
 and a systematic botanist, and one who had at his time 
 the widest knowledge of the distribution of plants, was of 
 invaluable assistance to Darwin on the botanical side of his 
 researches. Those who knew Hooker will remember him 
 as a man of ripe experience, sound judgment, and a very 
 evenly-balanced mind. But all these high and by no means 
 common qualities were combined with caution, and with a 
 critical faculty, which was quite invaluable to Darwin at 
 this juncture. Huxley was of a somewhat different tempera- 
 ment. He was rather proud of the fact that he was named 
 after the doubting apostle ; but, whatever Huxley doubted, 
 he never doubted himself. He had clear-cut ideas, which 
 he was capable of expressing in the most vigorous and 
 
 1 J. W. JuddT" 
 
280 Britain's Heritage of Science 
 
 the most cultivated English. Both on platform and on paper 
 he was a keen controversialist. He contributed much to 
 our knowledge of morphology. But never could he have 
 been mistaken for a field-naturalist. In the latter part of 
 his life he was drawn away from pure science by the demands 
 of public duty, and he was, undoubtedly, a power in the 
 scientific world. For he was ever one of that small band 
 in England who united scientific accuracy and scientific 
 training with influence on the political and official life of 
 the country. 
 
 As has already been said, the immediate effect of the 
 publication of " The Origin of Species " and of the acceptance 
 of its theories by a considerable and ever-increasing number 
 of experts did not lead to the progress of research along the 
 precise lines Darwin himself had followed. The accurate 
 description of bodily structure and the anatomical com- 
 parison of the various organs was the subject of one school 
 of investigators : Rolleston's " Forms of Animal Life," 
 re-edited by Hatchett Jackson, Huxley's " Vertebrate and 
 Invertebrate Zoologies," and Milnes Marshall's " Practical 
 Zoology " testify to this. Another school took up with 
 great enthusiasm the investigation of animal embryology, 
 the finest output of which was Balfour's " Text-book of 
 Embryology," published in 1880. Members of yet another 
 school devoted themselves to the minute structure of the 
 cell and to the various changes which the nucleus undergoes 
 during cell-division. Animal histology has, however, been 
 chiefly associated with physiology and, as this chapter is 
 already greatly overweighted, we have had to leave physio- 
 logy on one side. The subjects of degeneration, as shown, 
 by such forms as the sessile Tunicata, the parasitic Crustacea 
 and many internal parasitic worms, with the last of which 
 the name of Cobbold is associated, also received attention, 
 and increased interest was shown on the pathogenic influence 
 of internal parasites upon their hosts. 
 
 Towards the end of our period, a number of new schools 
 of biological thought arose. As Judd tells us : 
 
 " Mutationism, Mendelism, Weismannism, Neo-La- 
 
 marckism, Biometrics with which the name of W. F. R. 
 
 Weldon will ever be associated * Eugenics ' began to 
 
Alfred Russell Wallace 281 
 
 be exploited. But all of these vigorous growths have 
 their real roots in Darwinism. If we study Darwin's 
 correspondence, and the successive essays in which he 
 embodied his views at different periods, we shall find 
 that variation by mutation (or per saltum), the influence 
 of environment, the question of the inheritance of ac- 
 quired characters, and similar problems, were constantly 
 present to Darwin's ever open mind, his views upon them 
 changing from time to time, as fresh facts were gathered." 
 Like everything else, these new theories were deeply 
 rooted in the past. 
 
 We have already alluded to Alfred Russell Wallace 
 (1823-1913) and to the magnanimity with which he and 
 Darwin treated each other in the matter of their simul- 
 taneous discovery of the causes which had brought about 
 " The Origin of Species." Wallace was one of the last 
 of the great travelling naturalists and collectors. He 
 explored the Amazon with his friend Bates in the years 
 1848-1852. Two years later he visited and lived for some 
 years in the Indo-Malay Islands, and in both parts of the 
 globe he accumulated a vast series of facts from which 
 some of his widest generalisations sprang. 
 
 Wallace had a fine gift for writing, and his " Malay 
 Archipelago " is one of the most fascinating books in a 
 naturalist's library. Perhaps his most celebrated books are 
 his " Geographical Distribution of Animals " and " Island 
 Life," published in 1876, for, as Professor H. F. Osborn 
 reminds us, " Wallace takes rank as the founder of the 
 science of zoo-geography." " Wallace's Line " between 
 Bali and Lombok, the frontier between the Indian and 
 Australian regions, will ever recall his fame in this branch 
 of science. 
 
 He was a man of strong humanitarian instincts and 
 devoted a considerable amount of time in trying to devise 
 plans to help mankind and the state, and although many of 
 his views did not commend themselves to the majority his 
 sincerity was always fully recognized. 
 
 We must now return to many zoologists of about 
 Darwin's period who more than held their own as compared 
 with some continental claimants of scientific superiority. 
 
282 Britain*s Heritage of Science 
 
 Although George James Allman (1812-1898) was Pro- 
 fessor of Botany at Dublin, he achieved his most marked 
 success as a zoologist. He left Dublin in 1856 on his 
 appointment to the Regius Professorship of Natural History 
 in the University of Edinburgh. He was, like so many men 
 of science, a good artist, and had exceptional skill in drawing 
 on the blackboard, and was a very popular lecturer, and he 
 took especial pleasure in taking his pupils on dredging 
 expeditions in the Firth of Forth and inducing them to 
 study marine organisms in the living state. His great work 
 on the Gymnoblastic Hydrozoa, published by the Ray 
 Society, is stated by his biographer to have been without 
 doubt the most important systematic work dealing with the 
 group of Ccelenterata that has ever been produced. " The 
 excellence of the illustrations alone would almost justify 
 us in placing this work in the first rank of zoological treatises." 
 But he was equally an authority on certain groups of Polyzoa, 
 and it should be recalled that he it was who invented the 
 terms " ectoderm " and " endoderm," besides a great many 
 other useful expressions, such as " ccenosarc," " tropho- 
 some " and " gonosome," and many others. But above all 
 he did much to clear up the difficulty of defining species in 
 the Ccelenterata. 
 
 Thomas Henry Huxley (1825-1895), a few years younger 
 than Wallace, was, as we have seen, another of Darwin's 
 supporters. He started life as a surgeon and, like Darwin, 
 owed much of his early reputation to a sea voyage. He 
 made a four years' cruise in H.M.S. Rattlesnake, 1846- 
 1850, during which he especially devoted himself to the 
 study of marine organisms. He was the first to dissociate 
 the hydrozoa from the star fishes, and the parasitic worms 
 and the infusoria, which had formed portions of Cuvier's 
 old group Radiata. He did much to clear up the relations 
 of the Medusa to the Hydroid, and he dwelt especially on 
 the two -layered condition of their body wall, pointing out 
 its analogy with the gastrula. Shortly after his return to 
 England in 1850, he was elected a Fellow of the Royal 
 Society at the unusually early age of 26. 
 
 As a morphologist, Huxley made immense advances. 
 Apart from his work on Co3lenterates, he investigated the 
 
Thomas Huxley, William Flower 283 
 
 structural life-history of the Ascidians, wrote on the 
 Mollusca, and undertook a series of investigations into 
 fossil vertebrate forms, researched on Aphis and on croco- 
 diles, cleared up the mystery of the vertebrate skull, 
 and, in fact, covered an extremely wide area of investi- 
 gation. But Huxley was not only a great morphologist, 
 he was a great teacher and a great organiser. His text 
 books on the comparative anatomy of the Vertebrate and 
 of the Invertebrata were the starting points of many a 
 zoologist's career. His " Elementary Biology," which he 
 wrote in collaboration with Newail Martin, marks an epoch. 
 He was also a great lecturer, and although not fond of public 
 speaking, he was remarkably able, concise, and even 
 eloquent. He spared no pains, and would write and re- 
 write an address until he had got it into what he considered 
 a satisfactory form. Further, as he himself wrote of 
 Priestley, he was " a man and a statesman before he was 
 a philosopher," and Huxley took a leading part in public 
 affairs, sat on a large number of Royal Commissions and 
 departmental committees. He was a member of the first 
 School Board of the City of London, and by his popular 
 lectures made a real attempt to interest the working men 
 and all others in the importance of science. He was, for a 
 time, the Biological Secretary of the Royal Society, and in 
 this post took a large part in organizing the Challenger 
 Expedition of 1872-1876. He was elected President of the 
 Royal Society, but four years later was compelled to resign 
 on account of ill-health. He was the recipient of innumerable 
 honorary degrees and memberships of foreign societies, and 
 in 1892 was honoured by being made a Privy Councillor. 
 
 Owen's successor, Sir William Flower (1831-1899), was 
 trained at the University of London as a medical man, and 
 after touring on the Continent, he joined the army, and 
 was assistant surgeon hi the 63rd Regiment during the 
 Crimean Campaign, the trials of which were so severe that 
 his health was affected, and he had to retire from the army 
 and return to London. For a time he practised, but in 
 1861, was appointed Conservator of the Museum of the 
 Royal College of Surgeons, and here he found his career. 
 This unique museum was greatly increased under Flower. 
 
284 Britain's Heritage of Science 
 
 The President of the Royal Society said, when presenting 
 Sir William with a royal medal, " it is very largely due to his 
 incessant and well-directed labours that the Museum of 
 the Royal College of Surgeons at present contains the most 
 complete, the best ordered, and the most accessible collec- 
 tions of materials for the study of vertebrate structures 
 extant." 
 
 Flower succeeded Huxley in the Hunterian Professor- 
 ship at the Royal College of Surgeons, and his lectures met 
 with great success, in fact, he was soon becoming the fore- 
 most authority on mammals, and his work on " Mammals, 
 Living and Extinct," which he published in London in 
 conjunction with Lydekker, is still regarded as a classic. 
 Perhaps if he had a favourite group it was the Cetacea, and 
 when he succeeded Owen as Superintendent of the Natural 
 History Museum at Kensington, he took the greatest 
 pleasure in having a large room specially constructed to house 
 their gigantic skeletons. His well-known " Osteology of 
 Mammals," in which he was assisted by Dr. Hans Gadow, 
 was, even if a little dry, one of the most accurate and com- 
 plete of student's books. Another side of his work was 
 Anthropology. He published innumerable papers on the 
 various races of mankind, fully utilising the valuable material 
 he had at the Royal College of Surgeons. In 1879 he was 
 elected President of the Zoological Society, and held the 
 position until his death. His energy greatly increased the 
 value and use of the gardens. In 1898 failing health com- 
 pelled him to retire from the position. Sir William was 
 a handsome, well-set-up man, always courteous to strangers, 
 with a ready, fluent address. 
 
 One of the unexpected results of Darwin's investigations 
 was to induce a number of the younger school of zoologists 
 to take up the study of Embryology. The most brilliant 
 of these was Francis Maitland Balfour (1851-1882). He 
 was educated at Harrow and at Trinity College, Cambridge. 
 Even as a student acting under the advice of Michael 
 Foster, at that time Praelector of Physiology in Trinity 
 College he devoted himself to clearing up some points in 
 the development of the chick. After taking his degree in 
 1873, he worked on the embryonic history of the Elasmo- 
 
W. Flower, F. M. Balfour, A. Sedgwick 285 
 
 branch fishes at the Zoological Station at Naples. This 
 research gained him a Fellowship at Trinity College. 
 
 He was appointed lecturer on Animal Morphology at 
 Cambridge, and soon became the founder of an extremely 
 vigorous and active school of zoologists. His best known 
 work is, of course, his " Treatise on Comparative Embryo- 
 logy," the first volume of which appeared in 1880, and the 
 second in the following year. It was a masterly review of an 
 enormous number of observations scattered over a world- 
 wide literature, and its production involved a wide and 
 careful reading of multitudinous papers. He had remark- 
 able critical faculty, and a wonderful gift of insight and 
 intuition, so that his book threw light on many a doubtful 
 point. When he was but 27, he was elected a Fellow of 
 the Royal Society, and, if he had chosen, he might have 
 succeeded Rolleston as Professor at Oxford. Edinburgh 
 also coveted him; but he remained faithful to his own 
 University, and, in the spring of 1882, a special Professorship 
 of Animal Morphology was instituted for him at Cambridge. 
 
 Balfour died by a tragic accident in the Alps in the 
 summer of 1882, and in him died a young man of great 
 performance, and even greater promise. He was a man of 
 singular charm, and, as Professor Michael Foster wrote, 
 " he was high-minded, generous, courteous, a brilliant 
 fascinating companion, a steadfast friend. He won, as few 
 others did, the hearts of all who were privileged to know 
 him." 
 
 We must necessarily deal but shortly with a few more 
 names : 
 
 George John Romanes (1848-1894), whose researches on 
 the physiology of the nervous and locomotor system of 
 jelly-fishes and echinoderms, and whose speculations on the 
 principle of Selection will preserve his name. 
 
 Adam Sedgwick (1854-1913), a great nephew of the 
 geologist, by his researches on Peripatus did much to eluci- 
 date the mystery of the Coelom in Arthropods, and so show 
 a possible connexion between this group and lower animals. 
 His views on the cell theory are now coming to their own. 
 For a year or two he was Professor of Zoology at Cambridge, 
 and at the time of his death he was Professor at the Royal 
 
286 Britain's Heritage of Science 
 
 College of Science and Technology, in London, and though 
 he was by no means a fluent lecturer, he was a stimulating 
 and inspiring teacher. 
 
 Walter Frank Raphael Weldon (1860-1906), another 
 Cambridge man, succeeded Moseley as Professor at Oxford. 
 He was a brilliant teacher, full of enthusiasm, and did much 
 sound morphological work. The last years of his life he 
 devoted to the subject of Biometrics, and he was the co- 
 founder with Karl Pearson of Biometrika. 
 
 The mention of Biometrics recalls the name of one who, 
 though not a zoologist in the strict sense of the word, deserves 
 a distinguished place in the history of our subject. Francis 
 Galton (1822-1911) began active life as a student of medicine, 
 but, on his father's death, inherited independent means and 
 abandoned the professional career. He spent some time on 
 an extensive journey in Africa, but his mind soon turned 
 to science. It was, probably, his experiences as a traveller 
 that directed his attention, at first, to meteorology, and he 
 did some useful work hi that subject. On the publication 
 of the " Origin of Species," Galton at once adopted the 
 views advocated by Charles Darwin, who was his cousin. 
 He then became interested in the laws of heredity, and during 
 a series of years endeavoured to introduce scientific measure- 
 ments into the study of a subject in which previously quali- 
 tative estimates were considered sufficient. Feeling the 
 want of proper statistics, he instituted, during the National 
 Health Exhibition in 1884, an anthropometric laboratory, 
 for the purpose of collecting satisfactory data. This was 
 the forerunner of the present biometric laboratory at 
 University College, London. Following up suggestions by 
 Sir William Herschel and Dr. Foulds, who had proposed the 
 use of " finger-prints " as a means of identifying persons. 
 Galton proved the method to be reliable, and devised a 
 workable scheme for classifying the prints so as to make 
 them serviceable for rapid identification. He was also the 
 originator of the word " Eugenics " for the study of the 
 methods of improving the human race by breeding from the 
 best, and restricting the offspring of the worst ; and he must 
 be considered to be the founder of that branch of science. 
 Endowed with exceptional originality and a sympathetic 
 
W. F. A. Weldon, F. Galton, E. R. Lankester 287 
 
 mind that allowed him to co-operate effectively with other 
 men, he rendered many useful services to science. He was 
 knighted in 1909, two years before his death. By his will 
 he left a sum amounting to about 45,000 for the foundation 
 of a chair of Eugenics in the University of London, expressing 
 the wish that Karl Pearson should be the first occupant of 
 tKe chair. 
 
 One of the rules laid down for the writers of this book 
 is that living authors should only be mentioned when their 
 work is so much interwoven with that of others whose 
 activities have been noticed that a wrong impression would 
 be created by omitting all reference to them. Professor 
 Sir E. Ray Lankester has added so much to our conceptions 
 of the morphology of the animal kingdom, so much more 
 than any other living man, that a short account of his re- 
 searches must be given. Mention must be made of his 
 investigation into the embryonic cell gland of the Mollusca, 
 his researches in the distribution of haemoglobin in the 
 Invertebrata, the wonderful way in which he, in collabora- 
 tion with one of his pupils, cleared up the structure of the 
 Lamellibranch gill, his work on the anatomy of the Limpet, 
 and the even more important series of investigations which 
 led to the assignment of Limulus to its proper position 
 amongst the Arachnids. He was the first to observe an 
 intracellular parasite (in the red corpuscle of the frog), but 
 from the scales of fossil fishes to the details of the Okapi, 
 there are few subjects in Zoology that do not owe something 
 to the investigations carried on by Lankester from 1862 
 to 1905. His name will ever be associated with the very 
 important and fundamental conception of the coelom, and 
 his views on this subject are set forth at length in Part II 
 of his Treatise on Zoology. With this theory must be 
 associated his views on Phleboedesis, a name given to the 
 theory that the lacunar blood-holding spaces forming the 
 haemocoel of the Mollusca and the Crustacea have no 
 connexion with the coelom, although they encroach in 
 certain animals on the space occupied by the coelomic 
 cavity. The discussion of how his theory differs from that 
 given in " Die Coelom Theorie " of the Hertwigs is set out 
 in the above-mentioned treatise. 
 
288 Britain's Heritage of Science 
 
 In addition to these fundamental conceptions which have 
 done so much to clear up the structure of widely differ- 
 ing animals, Lankester has introduced many new terms 
 which have proved of permanent value in the science of 
 zoology. Amongst these may be mentioned " nephridium," 
 " blastoderm," " stomodeum," " proctodeum." Further, 
 he introduced the terms " homogeny " and " homoplasy," 
 to distinguish between the two very different senses in which 
 " homology " had previously been used. 
 
 As a maritime nation, Great Britain has led the way in 
 exploring the plant life and animals of the sea, the chemical 
 and physical nature of the sea water, and the geological 
 structure of the subaqueous earth. As long ago as 1749 
 Captain Ellis found that a thermometer, lowered on separate 
 occasions to depths of 650 fathoms and 891 fathoms respec- 
 tively recorded, on reaching the surface, the same tempera- 
 ture, namely, 53. His thermometer was lowered in a 
 bucket ingeniously devised so as to open as it descended 
 and close as it was drawn up. The mechanism of this instru- 
 ment was invented by the Rev. Stephen Hales, D.D., to 
 whom we have referred above. Dr. Hales was an ingenious 
 soul and the author of many inventions, amongst others, 
 he is said to have suggested the use of the inverted cup 
 placed in the centre of a fruit-pie in which the juice 
 accumulates as the pie cools. His device of the closed 
 bucket with two connected valves was the forerunner of 
 the numerous contrivances which have since been used for 
 bringing up sea- water from great depths. The colour of 
 the sea and its salinity had also received attention in early 
 days, notably at the hands of the distinguished chemist, 
 Robert Boyle. 
 
 The invention of the self-registering thermometer by 
 Cavendish in 1757, provided another instrument essential 
 to the investigation of the condition of things at great 
 depths, and it was used in Lord Mulgrave's expedition to 
 the Arctic Sea in 1773. On this voyage attempts at deep- 
 sea soundings were made, and a depth of 683 fathoms was 
 registered. During Sir James Ross's Antarctic Expedition 
 (1839-1843) the temperature of the water was constantly 
 observed to depths of 2,000 fathoms. His uncle, Sir John 
 
Marine Zoology 289 
 
 Ross, had, twenty years previously, on his voyage to 
 Baffin's Bay, made some classical soundings. One, two 
 miles from the coast, reached a depth of 2,700 feet, and 
 brought up a collection of gravel and two living crustaceans ; 
 another, 3,900 feet in depth, yielded pebbles, clay, some 
 worms, Crustacea, and corallines. Two other dredgings, 
 one at 6,000 feet, the other at 6,300 feet, also brought up 
 living creatures; and thus, though the results were not at 
 first accepted, the existence of animal life at great depths 
 was demonstrated. 
 
 With Sir James Ross's expedition we may be said to 
 have reached modern times; his most distinguished com- 
 panion, Sir Joseph Hooker, died as recently as 1911. It is 
 impossible to do more than briefly refer to the numerous 
 expeditions which have taken part in deep-sea exploration 
 during our own times 
 
 Professor Edward Forbes, who " did more than any 
 of his contemporaries to advance marine zoology," joined 
 the surveying ship Beacon in 1840, and made more than one 
 hundred dredgings in the ^Egean Sea. Mr. H. Goodsir sailed 
 on the Erebus with Sir John Franklin's ill-fated Polar 
 Expedition; and such notes of his as were recovered bear 
 evidence of the value of the work he did. In 1868 the 
 Admiralty placed the surveying ship Lightning at the disposal 
 of Professor Wyville Thomson and Dr. W. B. Carpenter 
 for a six weeks' dredging cruise in the North Atlantic; and 
 in the following year the Porcupine, by permission of the 
 Admiralty, made three cruises under the guidance of 
 Dr. W. B. Carpenter and Mr. Gwynne Jeffreys. 
 
 We owe to Forbes (1815-1854) the delimitation of this 
 zone of depth usually distinguished in European and other 
 seas. These are the Littoral zone, the Laminarian zone, 
 the Coralline zone, and the region of the deep sea corals. 
 The last two zones are now generally known as the Conti- 
 nental Shelf and the Continental Slope, and to these must 
 be added the floor of the deep ocean, a region which in 
 Forbes* time was regarded as uninhabited. Forbes, after 
 a very varied career, ultimately became a Professor at 
 King's College, London, and Curator of the Museum of the 
 Geological Society. His work in connexion with palaeonto- 
 
 T 
 
290 Britain's Heritage of Science 
 
 logy will be described in the chapter on Geology. He is 
 undoubtedly the leading naturalist of the earlier half of the 
 nineteenth century, a man of wide interests and of great 
 popularity, one who lived a full life, one who promoted 
 science, and who rendered a real service to every branch of 
 Biology. 
 
 Another naturalist of the same period was Phillip Henry 
 Gosse (1810-1888). As a young man he lived in Newfound- 
 land, and here it was he began the serious study of Nature. 
 His first work was on the Entomology of Newfoundland. 
 Later, he travelled extensively in North America. On 
 returning to England in 1839 he wrote his " Canadian 
 Naturalist." A few years later he was in Jamaica, collecting 
 and describing the native fauna and sending many specimens 
 home. His " Birds of Jamaica," illustrated by a series of 
 magnificent plates, is well known. But, perhaps, Gosse 's 
 name will live longer as a researcher on Marine Inverte- 
 brates. He particularly occupied himself with the zoophytes 
 and made a great hit with his book " The Aquarium," which 
 did much to stimulate amateurs to observe the littoral 
 fauna. His most serious contribution to science, however, 
 was his study of the sea anemones, Actinologia britannica 
 (1855-1860); but it must not be forgotten that he colla- 
 borated with Dr. Hudson in the fascinating two volumes 
 which these joint authors published in 1866 on the Rotifera. 
 
 Towards the end of 1872 H.M.S. Challenger left England 
 to spend the following three years and a half in traversing 
 all the waters of the globe. This was the most completely 
 equipped expedition which has left any land for the investi- 
 gation of the sea, and its results were correspondingly rich. 
 They have been worked out by naturalists of all nations, 
 and form the most complete record of the fauna and flora, 
 and of the physical and chemical conditions of the deep, 
 which has yet been published. Since the return of the 
 Challenger there have been many expeditions from various 
 lands, but none so complete in its conception or its 
 execution, as the British Expedition of 1872-1876. 
 
 The results of the exploration of the sea by the Challenger 
 have never been equalled. In one respect, however, they 
 were disappointing. It had been hoped that, in the deeper 
 
Marine Zoology 291 
 
 abysms of the sea, creatures whom we only know as geo- 
 logical, fossilized, bony specimens, might be found in the 
 flesh; but, with one or two exceptions and these of no 
 great importance these were not found. Neither did any 
 new type of organism appear. Nothing, in fact, was dredged 
 from the depths or found in the tow-net that did not fit 
 into the larger groups that already had been established 
 before the Challenger was thought of. On the other hand, 
 many new methods of research were developed during this 
 voyage, and with it will ever be associated the names of 
 Wyville Thompson, mentioned above, Moseley, John Murray 
 and others who, happily, are still with us. 
 
 A few words should be said as to the part played by 
 cable-laying in the investigation of the subaqueous crust of 
 the earth. This part, though undoubtedly important, is 
 sometimes exaggerated; and we have seen how large an 
 array of facts has been accumulated by expeditions made 
 mainly in the interest of pure science. The laying of the 
 Atlantic cable was preceded, in 1856, by a careful survey 
 of a submerged plateau, extending from the British Isles 
 to Newfoundland, by Lieutenant Berryman of the Arctic. 
 He brought back samples of the bottom from thirty-four 
 stations between Valentia and St. John's. In the following 
 year Captain Pullen, of H.M.S. Cyclops, surveyed a parallel 
 line slightly to the north. His specimens were examined by 
 Huxley, and from them he derived the Bathybius, a primeval 
 slime which was thought to occur widely spread over the 
 sea-bottom and to be the most primitive form of living 
 matter. The interest in this " Urschleim " became merely 
 academic, when John Y. Buchanan, of the Challenger, showed 
 that it is only a gelatinous form of sulphate of lime, thrown 
 down from the sea-water by the alcohol used in preserving 
 the organisms found in the deep-sea deposits. It was 
 characteristic of Huxley to acknowledge his mistake and 
 never to mention the subject again. 
 
 The important generalizations of Dr. Wallich, who was 
 on board H.M.S. Bulldog, which, in 1860, again traversed 
 the Atlantic to survey a route for the cable, largely helped 
 to elucidate the problems of the deep. Wallich noticed 
 that no algce lived below the 200 fathom line; he collected 
 
 T 2 
 
292 Britain's Heritage of Science 
 
 animals from great depths, and showed that they utilize 
 in many ways organisms which fall down from the surface 
 of the water; he noted that the conditions are such that, 
 whilst dead animals sink from the surface to the bottom, 
 they do not rise from the bottom to the surface; and he 
 brought evidence forward in support of the view that the 
 deep-sea fauna is directly derived from shallow-water forms. 
 In the same year in which Wallich traversed the Atlantic, 
 the telegraph cable between Sardinia and Bona, on the 
 African coast, snapped. Under the superintendence of 
 Fleeming Jenkin, some forty miles of the cable, part of it 
 from a depth of 1,200 fathoms, were recovered. Numerous 
 animals, sponges, corals, polyzoa, molluscs, and worms were 
 brought to the surface, adhering to the cable. These were 
 examined and reported upon by Professor Allman, and 
 subsequently by Professor A. Milne Edwards; and, as the 
 former reports, we " must therefore regard this observa- 
 tion of Mr. Fleeming Jenkin as having afforded the first 
 absolute proof of the existence of highly organized animals 
 living at a depth of upwards of 1,000 fathoms." The 
 investigation of the animals thus brought to the surface 
 revealed another fact of great interest, namely, that some 
 of the specimens were identical with forms hitherto known 
 only as fossils. It was thus demonstrated that species 
 hitherto regarded as extinct are still living at great depths 
 of the ocean. 
 
 Throughout the century repeated attempts had been 
 made to classify the members of the animal kingdom on 
 a natural basis, but, until their anatomy and, indeed, their 
 embryology had been sufficiently explored, these attempts 
 proved somewhat vain. As late as 1869 Huxley classified 
 sponges with Protozoa, Echinoderms with Scolecida and 
 Tunicates with Polyzoa and Brachiopoda. By the middle 
 of the century, much work had been done in sorting out 
 the animal kingdom on a natural basis, and Vaughan 
 Thompson had already shown that Flustra was not a hydroid, 
 but a member of a new group which he named Polyzoa. 
 He, although hardly remembered now, demonstrated that 
 Cirrepedia are not molluscs by tracing their development, 
 he established the fact that they began life as free-swimming 
 
F. D. Godman, 0. Salvin 293 
 
 Crustacea ; he, again, it was who showed that Pentacrinus is 
 the larval form of the feather-star, Antedon. 
 
 The custom of naturalists to go on long voyages was 
 still maintained, and during the nineteenth century, many 
 other expeditions besides that of the Challenger, left Great 
 Britain to explore the natural history of the world, some 
 under public, some under private, auspices. They are too 
 numerous to mention. But a word must be said about the 
 wonderful exploration of Central America which has just 
 been completed, under the auspices of F. D. Godman and 
 0. Salvin. The results are incorporated in a series of magni- 
 ficently illustrated quarto volumes which have been issued 
 during the last thirty -six years. Fifty -two of these relate 
 to zoology, five to botany, and six to archaeology. Nearly 
 40,000 species of animals have been described in these 
 volumes, about 20,000 being new species, and nearly 12,000 
 species of plants. There are few remote and partially 
 civilized areas of the world whose zoology and botany are 
 on so secure a basis, and this is entirely owing to the muni- 
 ficence and enterprise of the above-mentioned gentlemen. 
 
 With regard to our own shores, one of the features of 
 the latter part of the nineteenth century has been the 
 establishment of marine biological stations, the largest of 
 which is that of the Marine Biological Association at Ply- 
 mouth. The Gatty laboratory at St. Andrews, the labora- 
 tories at Port Erin in the Isle of Man, and at Cullercoats, 
 have also, for many years, being doing admirable work. 
 All these establishments have devoted much technical skill 
 and time to solve fishery and other economic problems 
 connected with our seas. 
 
294 Britain's Heritage of Science 
 
 CHAPTER XI 
 
 PHYSIOLOGY 
 
 HARVEY (1578-1657), who, like Newton, worked in one 
 of the two sciences which, in Stewart times, were, to 
 some extent, ahead of all the others, was undoubtedly the 
 second man of outstanding genius in science in the seventeenth 
 century. Harvey, " the little choleric man " as Aubrey 
 calls him, was educated at Caius College, Cambridge, and 
 at Padua, and was in his thirty-eighth year when, in his 
 lectures on anatomy, he expounded his new doctrine of 
 the circulation of the blood to the College of Physicians, 
 although his " Exercitatio " on this subject did not appear 
 till 1628. His notes for the lectures are now in the British 
 Museum. He was physician to Charles I., and it is on record 
 how, during the battle of Edgehill, he looked after the 
 young princes as he sat reading a book under a hedge a little 
 removed from the fight. 
 
 In the chain of evidence of his convincing demonstration 
 of the circulation of the blood one link, only to be supplied 
 by the invention of the compound microscope, was missing. 
 This, the discovery of the. capillaries, was due to Malpighi, 
 who was amongst the earliest anatomists to apply the com- 
 pound microscope to animal tissues. Still, as Dryden has it 
 
 " The circling streams once thought but pools of blood 
 (Whether life's fuel or the body's food), 
 From dark oblivion Harvey's name shall save." 1 
 
 Harvey was happy in two respects as regards his dis- 
 covery. It was, in the main, and especially in England, 
 recognized as proven in his own lifetime, and, again, no 
 one of credit claimed or asserted the claim of others to 
 priority. In research, all enquirers stand on steps others 
 have built up; but in this, the most important of single 
 contributions to physiology, the credit is Harvey's and 
 
 1 Epistle to Dr. Charleton. 
 
William Harvey 
 
 From a painting by Cornelius Janssen 
 
William Harvey 295 
 
 almost Harvey's alone. His other great work, " Exercita- 
 tiones de Generatione Animalium," is of secondary import- 
 ance. It shows marvellous powers of observation and very 
 laborious research; but although, to a great extent, it led 
 the way in embryology, it was shortly superseded by the work 
 of those who had the compound microscope at their command. 
 The poet, Cowley, a man of wide culture, wrote an " Ode 
 on Harvey," in which his achievement was contrasted with 
 a failing common to scientific men of his own time, and, 
 so far as we can see, of all time : 
 
 " Harvey sought for Truth in Truth's own Book 
 The Creatures, which by God Himself was writ; 
 
 And wisely thought 'twas fit, 
 Not to read Comments only upon it, 
 But on th' original itself to look. 
 Methinks in Arts great Circle, others stand 
 Lock't up together, Hand in Hand, 
 
 Every one leads as he is led, 
 
 The same bare path they tread, 
 A Dance like Fairies a Fantastick round, 
 But neither change their motion, nor their ground : 
 Had Harvey to this Road confin'd his wit, 
 His noble Circle of the Blood, had been untrodden yet." 
 
 Harvey's death is recorded in a characteristic seventeenth 
 century sentence, taken from the unpublished pages of 
 Baldwin Harvey's " Bustorum Aliquot Reliquiae " : 
 
 " Of William Harvey, the most fortunate anatomist, 
 the blood ceased to move on the third day of the Ides 
 of June, in the year 1657, the continuous movement of 
 which in all men, moreover, he had most truly asserted 
 
 "Ev T ro< iravTfS KOI cvl Trac 
 
 1 The writer is indebted for this quotation to Dr. Norman Moore's 
 " History of the Study of Medicine in the British Isles," Oxford, 
 1908. He may here add a short note on the " Tabulae Harveianee," 
 presented in 1823 by the Earl of Winchelsea to the Royal College of 
 Physicians. Sir Thomas Barlow, in his Harveian Oration of 1916, 
 threw much doubt on these " Tavole " having belonged to Harvey; 
 and Dr. Archibald Malloch, of the Canadian Army Medical Corps, 
 has, in his recently published lives of Sir John Finch and Sir Thomas 
 Baines, brought forward almost conclusive evidence that these 
 " Tavole " belonged to the former of these two gentlemen, and were 
 brought by him from Padua, where, with his friend, he had studied 
 medicine. 
 
298 Britain's Heritage of Science 
 
 Among other great physiologists and physicians, the 
 Swiss, Sir Theodore Turquet de Mayerne (godson of Theodore 
 Beza), who settled in London in 1611, has left us " Notes " 
 of the diseases of the great which, .to the medically minded, 
 are of the greatest interest. He almost diagnosed enteric, 
 and his observations on the fatal illness of Henry, Prince of 
 Wales, and the memoir he drew up in 1623 on the health 
 of James I., alike leave little to be desired in completeness 
 or in accuracy of detail. 
 
 Before bringing to a close these short notices of those 
 who studied and wrote on the human body, whole or dis- 
 eased, a few lines must be given to John Mayow (1640- 
 1679), of Oxford, who followed the law, " especially in 
 the summer time at Bath." Yet, from his contributions 
 to science, one might well suppose that he had devoted 
 his whole time to research in chemistry and physiology. 
 He it was who showed that, in respiration, not the whole 
 air, but a part only of the air breathed in, takes an active 
 part in respiration, though he called this part " by a different 
 name, he meant what we now call oxygen." * 
 
 Mayow showed that dark venous blood is changed to 
 bright red by taking up this unknown substance, and thus 
 was very near to discovering oxygen, for he fully grasped 
 the idea that the object of breathing is to cause an inter- 
 change of gases between the air and the blood, the former 
 giving off what he called its " nitro aero " constituent 
 (oxygen) taking away the " vapours engendered by the 
 blood." He was the first to find the seat of animal heat 
 in the muscles, to describe the double articulation of the 
 ribs and spine, and he discussed the function of the inter- 
 costal muscles in an entirely modern spirit. Had he been 
 spared he undoubtedly would have gone far, but he died 
 in Covent Garden at the too early age of thirty-five, having 
 been married a little time before " not altogether to his 
 content." 
 
 Thomas Sydenham was one of the first physicians who 
 was convinced of the importance of constant and prolonged 
 observation at the bedside of the patient. He passed by 
 
 1 Foster, Sir Michael, "The History of Physiology," Cambridge, 
 1901. 
 
Physiology and Medicine 297 
 
 all authority but one " the divine old man Hippocrates," 
 whose medicine rested also on observation. He, first in 
 England, " attempted to arrive at general laws about the 
 prevalence and the course and the treatment of disease 
 from clinical observation." He was essentially a physician 
 occupied in diagnosis, treatment and prognosis. When he 
 was but twenty-five years old, he began to suffer from gout, 
 and his personal experience enabled him to write a classic 
 on this disease, which is even now unsurpassed. 
 
 Francis Glisson, like Sydenham, was essentially English 
 in his upbringing, and did not owe anything to foreign 
 education. His work on the liver has made " Glisson's 
 capsule " known to every medical student, and he wrote 
 an authoritative book on rickets. He, like Harvey, was 
 educated at Gonville and Caius College, and, in 1636, 
 became Regius Professor of Physic at Cambridge, but the 
 greater part of his life he spent at Colchester. 
 
 A contemporary of Mayow was Richard Lower (1631- 
 1691), of Cornwall. He was the first to perform the operation 
 of directly transfusing blood from one animal to another. 
 In 1669 he injected dark venous blood into inflated lungs, 
 and found it became scarlet. This he attributed to something 
 which was being absorbed from the air which was being 
 passed through the lungs. In his " Tractatus de Corde " 
 he gave a more accurate description than anybody had 
 hitherto given of the structure of the heart, including its 
 innervation, and, having at his disposal more exact apparatus, 
 he was able somewhat to expand and complete Harvey's 
 exposition of the physiology of that organ. 
 
 Lower was for a time assistant to Thomas Willis (1621- 
 1675), whose name is commemorated by the " circle of 
 Willis " at the base of the brain. The " Cerebri Anatome " 
 of the latter (1664) was the most complete and detailed 
 account of the nervous system that had been published 
 up to this time, though his hypotheses as to the functions 
 of the parts he described left much to be corrected later. 
 In the preparation of this work he had been helped by 
 Lower and Sir Christopher Wren, who drew the illustrations. 
 Wilhs was as distinguished a physician as he was a 
 physiologist. 
 
298 Britain's Heritage of Science 
 
 A name that is sometimes overlooked in the history of 
 British Science is that of Clopton Havers (? 1650/60-1702). 
 He was for a time educated at St. Catherine's Hall, Cam- 
 bridge, but left the University without taking a degree. 
 He took the M.D. at Utrecht in 1685, and practised in the 
 city of London. But he was an anatomist as well as a 
 physician, and was the first to give an adequate account 
 of the structure of the bone, and this in his chief anatomical 
 work " The Osteologia Nova, or some new Observations 
 of the Bones and the parts belonging to them." His name 
 is commemorated by the Haversian Canals, a name which 
 is still used to designate those smaller channels of the bone 
 through which the blood-vessels pass. 
 
 British animal physiology, which had started magni- 
 ficently with Harvey, and had continued under Mayow, 
 de Mayerne and others, was carried forward by Stephen 
 Hales (1677-1761). He was a born experimenter, and, as 
 a student, worked in the " elaboratory of Trinity College," 
 which had been established under the rule of Bentley, ever 
 anxious to make his college the leader in every kind of 
 learning. We have said something about the contribution 
 of Stephen Hales to vegetable physiology, but he was no 
 less brilliant as an animal physiologist. In the second part 
 of his statical essays, entitled " Haemadynamics " (1733), 
 a real advance is recorded in the physiology of circulation. 
 Hales invented the manometer, with the aid of which he 
 was able to make quantitative estimates of blood-pressure, 
 and measure the velocity of the blood-current. He knew 
 how to keep blood fluid with saline solutions. He studied 
 the shape and form of muscles in contraction and at rest, 
 and had a considerable knowledge of secretion. He worked 
 much on gases and paved the way for Priestley and others 
 by devising methods of collecting them over water. Of 
 him, Sir Francis Darwin writes : 
 
 " In first opening the way to a correct appreciation 
 of blood-pressure Hales' work may rank second in 
 importance to Harvey's in founding the modern science 
 of physiology." 
 
 He was a master of scientific method and the greatest 
 physiologist of his century. There were, however, many 
 
S. Hales, W. Hewson, T. Young 299 
 
 others, and Professor Langley has summarized the work 
 of some of them in his " Sketch of the progress of the 
 discovery in the eighteenth century of the autonomic 
 nervous system." 1 
 
 In the eighteenth century a most distinct advance in 
 animal physiology was made north of the Tweed by Joseph 
 Black, whose work in Physics and Chemistry has already 
 been described (see p. 65). Investigating the properties of 
 carbonic acid gas or " fixed air," as it was then called, he 
 noted that " fixed air " is also present in expired air, and 
 is physiologically irrespirable, though not toxic. 
 
 William Hewson (1739-1774), a pupil of the Hunters (see 
 Chapter X.), became assistant to them, and John Hunter 
 left him in charge of his dissecting room when abroad with 
 the army. For a time Hewson was in partnership with 
 William Hunter. It was he who discovered the existence of 
 lymphatic and lacteal vessels in birds, reptiles and fishes, 
 a fact which was of great importance in view of the opinions 
 held by the Hunters that absorption is the function of these 
 vessels ; for hitherto the opponents of this view had pointed 
 to the absence of these organs in the lower vertebrates. 
 A more important work was embodied in his experimental 
 enquiry into the properties of blood (1771). Hewson showed 
 that when coagulation of the blood is delayed by cold or by 
 the addition of neutral salts, a coagulable fluid may be 
 separated from the corpuscles. He further showed this 
 fluid was an insoluble substance which could be precipitated. 
 According to Hewson's view, coagulation was due to the 
 formation of this substance which he called " coagulable 
 lymph," and which we now call " fibrinogen." For a time 
 his work was forgotten, but now at last its value is fully 
 recognized. 
 
 The Quaker physician, Thomas Young, whose brilliant 
 work in Physics has been described in our first chapter, was 
 the founder of the science of Physiological Optics. He 
 studied under John Hunter, and amongst his early discoveries 
 he showed that the accommodation of the eye to different 
 distances is due to changes in the curvature of the crystalline 
 
 1 Journal of Physiology, Vol. L., 1916. 
 
300 Britain's Heritage of Science 
 
 lens. He gave the first description of astigmatism of the 
 eye, and showed how it could be corrected by tilting the 
 lens, through which the object is looked at; but Young 
 had only come across a slight case of the defect. More 
 pronounced cases require cylindrical lenses, as subsequently 
 shown by Airy (p. 120). He also laid the basis of the theory 
 that colour vision is due to retinal structure corresponding 
 to red, green, and violet, and applied it to the explanation 
 of colour blindness. Young advanced Physiology also in 
 other directions, and in the Croonian Lecture, delivered in 
 1818, he stated the laws covering the flow of blood to the 
 heart and arteries. 
 
 Thomas Addison (1793-1860), from Cumberland, was a 
 brilliant pathologist, and owing to his not being a very 
 successful practitioner, lived almost entirely on his teaching 
 and hospital work. He was the first to employ electricity 
 in the treatment of various spasmodic disorders and heart 
 disease, and, together with John Morgan, he wrote the first 
 book in our language on the action of poisons on the living 
 body. He described pernicious anaemia, and in his work 
 " On the Constitution and Local Affection of Disease of the 
 Supra-renal Capsules," he described that disorder which is 
 always associated with his name. This book is now regarded 
 as the starting point of a long series of studies into the diseases 
 of the ductless glands. 
 
 A third researcher from the north of England was Sir 
 William Bowman (1816-1892), born in Cheshire, the well- 
 known ophthalmic surgeon. He contributed much to the 
 science of physiology. He it was who discovered and 
 described striated muscle, basement membranes, the ciliary 
 apparatus of the eyeball; but perhaps he is best known for 
 his research on the kidney, his theory being that while the 
 tubules and plexus and capillaries are the parts mostly 
 concerned in the secretions of urea, lithic acid, etc., the 
 malpighian bodies were the organs which separated the 
 watery constituents from the blood. 
 
 With the arrival of Michael Foster (1816-1907) in Cam- 
 bridge as Praelector in Physiology at Trinity College in 1870, 
 began an era of great activity in biological research in that 
 ancient University. This subject had been by no means 
 
T. Addison, W. Bowman, M. Foster 301 
 
 neglected under Professor Sir George Humphry, Professor 
 Clark, and others, but Foster brought with him new methods 
 and new conceptions. Owing to the religious tests demanded 
 in those times by the older Universities, Foster had been 
 educated at the University College, London, and after 
 practising as a country doctor for a very few years, he 
 became a teacher in Practical Physiology at his old College, 
 and in 1869 he was elected Professor in succession to Sharpey. 
 He also succeeded Huxley as Fullerian Professor at the Royal 
 Institution. For twenty-two years he acted as Biological 
 Secretary to the Royal Society, and in 1899 he presided over 
 the British Association at their meeting at Dover, in which 
 year he was created a K.C.B. In the year 1900 he was 
 elected M.P. for the University of London, but lost his seat 
 six years later by the small majority of twenty-four votes; 
 it makes one shudder to recall that a man of such outstanding 
 merit should have said : " Not till I became a Member of 
 Parliament did I understand what power meant." 
 
 When the new Statutes came in at Cambridge, a Pro- 
 fessorship of Physiology was established, in 1883, and Foster 
 was the first to hold it. He did but little in original research, 
 but was the cause of a vast amount of research in others. 
 Still he was to some extent a pioneer in the study of Histology 
 and introduced the staining of sections with log-wood or 
 hsematoxylin. H was notable as a teacher, and founded 
 one of the finest Schools of Physiology that has ever existed. 
 He was a brilliant writer and a masterly organiser, and 
 undoubtedly one of the best lecturers and * after-dinner 
 speakers in the last quarter of the nineteenth century. 
 
 On arriving in Cambridge he introduced courses of 
 practical demonstrations modelled on those which Huxley 
 was carrying on at about the same time in London, and from 
 the first he was surrounded by a brilliant group of students, 
 amongst whom were Balfour (see page 284), Walter Gaskell, 
 Sheridan Lee, J. N. Langley, Newall Martin, Sherrington, 
 George Adami, Henry Head, and many others. Foster's 
 text-book of Physiology, the first edition of which appeared 
 in 1876 and was followed by five others, was a classic, and, 
 although in so changing a subject, it was almost impossible 
 to keep pace with the advances of a growing science, it 
 
302 Britain's Heritage of Science 
 
 was, for its time, one of the most inspiring of authoritative 
 books. Foster published many other books, all of them 
 remarkable for clear and scholarly diction and a real charm 
 of style, for, like so many men of science, Foster wrote the 
 purest English. The latest of all, " A History of Physiology 
 during the Sixteenth, Seventeenth, and Eighteenth Centuries," 
 has been of the greatest use in the compilation of these chapters. 
 In 1887 he founded the Journal of Physiology, the first of 
 its kind in the English language, and remained sole editor of 
 it till a few years before his death. 
 
 His great organizing powers were shown in the foundation 
 of the Physiological Society and the International Congress 
 of Physiologists. As Secretary of the Royal Society, he 
 took a leading part in the establishment of the International 
 Association of Academies and the International Catalogue 
 of Scientific Papers. He was a member of numerous Royal 
 Commissions, and had to a marked extent the ear of the 
 Government. If Foster told the Treasury a certain thing 
 ought to be done, it usually was done. 
 
 Amongst the most brilliant pupils of Foster was Walter 
 Holbrook Gaskell (1847-1914), a member of the well-known 
 Liverpool family to which Mrs. Gaskell the novelist also 
 belonged. Gaskell came up to Cambridge in 1865, as a 
 mathematician, at the unusually early age of 17 and some 
 months. Four years later he took his degree as twenty- 
 sixth wrangler. He then started to study medicine. A 
 year later he fell under the magnetism of Foster, and imme- 
 diately began a series of works which have made his name 
 one of the best known in the history of modern physiology. 
 
 His work falls mainly under three heads. He began his 
 researches by studying the inner vation of blood vessels in 
 striated muscles, and was gradually carried on to the investi- 
 gation of the small arteries of the heart with varying reactions 
 of the blood. He found that small additions of alkali 
 increased their tone, and small additions of acid decreased 
 it, and he was one of the first to recognize that there is a 
 chemical control in the organs and tissues as well as a nervous 
 one. Later he turned his attention to the inner vation of 
 the heart and the cause of the heart beat. At that time it 
 was held that the nerve cells present in the tissues of the 
 
Michael Foster, Walter Gaskell 303 
 
 heart control its beat. But there is some evidence that the 
 nerves were not the sole controlling cause, and in a series 
 of masterly papers Gaskell expounded the view of the 
 muscular origin of the beat, and showed how the beat is 
 conducted in the four chambers of the heart. Recently 
 great advances have been made in the application of physio- 
 logical methods to the clinical examination of the heart, and 
 this great help to suffering humanity is largely based upon 
 Gaskell 's work. His studies on nerves led him on to investi- 
 gate the structure, origin, and connexions of the sympa- 
 thetic nervous system. He described the relations of these 
 ganglia with the spinal cord, and gave an accurate inter- 
 pretation of their mode of action. His last book, the proof 
 sheets of which he finished correcting the day before the 
 stroke which ended his life, is entitled " The Involuntary 
 Nervous System." 
 
 In the early nineties he turned away from his normal 
 work to investigate the action of chloroform on the heart. 
 A Commission had been formed and financed by the Nizam 
 of Hyderabad to investigate the cause of death under 
 chloroform. The Commission reported that death was 
 usually due to the action of the respiratory centre. On 
 re-investigating, with the assistance of Dr. L. Shore of 
 St. John's College, Cambridge, it was found that chloroform 
 had a direct weakening effect on the heart, and that respira- 
 tion is not the only factor to be watched when that anaesthetic 
 is administered. 
 
 Gaskell's work had always been rather on the morpho- 
 logical side, and his third line of enquiry was into the origin 
 of vertebrates from invertebrates. His work on this subject 
 is a monument of ingenuity and a monument of patience. 
 In his view, vertebrates had been derived from some possible 
 crustacean or arachnid-like ancestor, and his investigations 
 into the structure and histology of Limulus and of the larval 
 lamprey added vastly to our knowledge of these organisms. 
 But in spite of all his ingenuity and all his patient persistence, 
 he failed to carrry conviction to the heart of his critics, and 
 all we can say about it is that his theory, like other theories 
 of the origin of vertebrates from invertebrates, is still 
 unproven. 
 
304 Britain's Heritage of Science 
 
 Gaskell was a man of broad views. Every new fact he 
 succeeded in establishing he used as a basis for further 
 generalization. He took comparatively small part in the 
 management of the University, but from time to time and 
 whenever really needed, he was willing to place his services 
 at the disposal of what was considered the reforming party 
 in University politics. 
 
 During the first half of the nineteenth century, Physiology 
 when it was taught at all was almost invariably taught by 
 medical men in active practice at the various London and 
 other hospitals. As a rule the doctor predominated over 
 the physiologist, and physiology in those days was not so 
 clearly defined a science as it has since become. Perhaps 
 the most outstanding name of this period is William Sharpey 
 (1802-1880). He was educated in Edinburgh, and was a 
 pupil of Dr. John Barclay, Extra-mural Lecturer at that 
 university. He subsequently studied at Paris. On re- 
 turning to England he started a private practice, but he 
 lacked a good bedside manner, and was obviously unsuited 
 for the duties of a practitioner, so from 1826 onwards he 
 devoted himself entirely to pure science. He spent some 
 years abroad trudging the roads in true medieval style from 
 one university town to another in Central Europe, and in 
 1829 he established himself as a teacher in Edinburgh. Later 
 he succeeded James Quain as Professor of Anatomy and 
 Physiology in what was then the University of London, and 
 is now known as University College, Gower Street, and here 
 for the first time a complete course of lectures on Physiology 
 were delivered by one who was purely a physiologist. He 
 was a born teacher, and his lectures were models both in 
 matter and form. For a time he was Secretary to the Royal 
 Society and a member of the General Council on Medical 
 Education and Registration. 
 
 Sharpey was a master of sound judgment, extraordinary 
 memory, and one who could deeply interest his pupils in the 
 subject he had at heart. Amongst his scholars were Michael 
 Foster and Burdon Sanderson, the latter of whose work at 
 London and Oxford notably carried on the tradition of his 
 master. Although Sharpey was a man of force and power 
 he, like Michael Foster, was perhaps more instrumental in. 
 
W. C. Sharpey, L. C. Wooldridge 305 
 
 getting published the work of his students than of publishing 
 his own; but the few papers, which are enumerated in the 
 " Dictionary of National Biography " under his name, are 
 papers of permanent value. 
 
 We have mentioned before that men of science were less 
 specialized at the earlier part of our period than they have 
 now become. Even the holding of professorial chairs in the 
 earlier part of the nineteenth century usually involved 
 teaching in more than one science. Up to the year 1866, 
 the professor of anatomy at Cambridge was responsible for 
 the teaching of zoology as well as for that of anatomy. In 
 many other places, the professorship of zoology was respons- 
 ible for what teaching there was in animal physiology, as 
 at Manchester, where W. C. Williamson combined the chairs 
 of botany, geology, zoology and animal physiology. In the 
 London hospitals, strictly scientific subjects were taught by 
 doctors in practice who were on the staff of the hospital. 
 
 It is quite impossible to detail the varied and successful 
 activities of the numerous physiologists who have worked 
 during the last forty years. Conspicuous amongst them was 
 Wooldridge. He was a pioneer. He was convinced that 
 many of the chemical and quasi-chemical problems presented 
 by the processes of life had been attacked too much by 
 laboratory methods remote from the animal itself. He 
 turned to the coagulation of blood as a type of such processes, 
 and decided that an analysis of the phenomenon must involve 
 observations upon the reactions offered by the living animal. 
 He developed the technique of injecting extracts of tissue 
 and organs into the circulation, and rapidly obtained results 
 which gave new conceptions to physiology. 
 
 He did not live to produce a finished theory of blood 
 coagulation, but it is not too much to. say that his work 
 initiated the modern studies of immunity, and was the 
 foundation of what is almost a new science. 
 
 It is not proposed to enter into the consideration of the 
 enormous advances that English men of science have con- 
 tributed to the practice of medicine and the alleviation of 
 pain. Sir James Young Simpson (1811-1870) discovered 
 chloroform, thereby immensely improving the possibilities 
 of operations, and to a quite unbelievable extent reducing 
 
306 Britain's Heritage of Science 
 
 pain, not only of our poor suffering humanity, but of the 
 animal creation. Edward Jenner (1749-1823) led the way 
 with vaccines and for the first time introduced the practice 
 of preventive innoculations. Sir Charles Bell (1774-1842) 
 cleared up the relations between the functions of the anterior 
 and posterior roots of the spinal column, and made numerous 
 other discoveries on the nervous system; and Lord Lister, 
 whose father had almost re-invented the compound micro- 
 scope, made many discoveries, by far the most important 
 of which wa r * his definite discovery of the part played by 
 micro-organisms in wounds. The antiseptic principle in 
 the practice of surgery dates from him and from his time, as 
 Dr. F. H. Garrison says, " when his body was laid to rest 
 in Westminster, England had buried her greatest surgeon." 
 
 It is impossible to deal with more than but a very few 
 of the distinguished physiologists who were working at the 
 close of the last century. One of these, however, must be : 
 Charles Smart Roy (1854-1897), who was educated at 
 St. Andrews and the University of Edinburgh. He fought 
 through the Turco-Serbian War, and whilst in Epirus 
 invented his frog cardiometer. For a time he was assistant 
 at Strassburg University, and here it was that he invented 
 the instrument which is best known in connexion with his 
 name, the Renal Oncometer, for the study of the variations 
 of the blood-flow through the kidney. Later, as George 
 Henry Lewes Student, he worked with Foster at Cambridge, 
 and in 1884 was elected to the Fellowship of the Royal Society, 
 and shortly afterwards was appointed first Professor of 
 Pathology in the University of Cambridge. 
 
 Hampered by ill-health and by want of accommodation 
 at the laboratory, he nevertheless produced work of great 
 value, and he succeeded in training a number of students 
 of great eminence, amongst whom J. G. Adami, W. Hunter, 
 Alfred Kanthack, Lorrain Smith, W. Westbrook, and Lewis 
 Cobbett, deserve record. 
 
 With Adami he carried out a long series of researches on 
 the mammalian heart, which involved the invention of the 
 cardiac-plethysmograph and the cardio-myograph, which 
 greatly helped to overcome the mechanical difficulties of the 
 subject. But he by no means confined his attention to this 
 
E. Jenner, J. Lister, C. S. Roy 307 
 
 branch of pathology. He had been instrumental in checking 
 a cattle plague in the Argentine Republic by protective 
 inoculation, and in 1885 proceeded to Spain to investigate 
 an outbreak of cholera which threatened to be serious. 
 
 As a lecturer he showed little interest in his pupils, but 
 to a researcher he was kindness itself, and unremitting in 
 his helpful aid. He was one of the few who at that time 
 were convinced that aviation was coming, and he made 
 several experiments on flying machines. 
 
 U 2 
 
308 Britain's Heritage of Science 
 
 CHAPTER XII 
 GEOLOGY 
 
 IN tracing the progress of any line of scientific research 
 it very often happens that our enquiries are largely 
 centred round the life of one man. It may be that he has 
 only collected and put into shape ideas which have been 
 growing in men's minds when at last a flash of genius has 
 illuminated the paths of research and the wisdom of many 
 has been crystallized by the wit of one. 
 
 It may be that a fortuitous display of phenomena not 
 before exhibited has appealed .to the imagination of men, or 
 combinations of opportunity and talent have started local 
 intelligence upon the paths of observation. 
 
 The striking variety and obvious relations of surface- 
 features and rock-characters in England have undoubtedly 
 had much influence in starting geological observations in 
 this country. England is only a small bit of the contorted 
 western margin of the uplifted Eurasian continent. The 
 great folds which brought it all up within reach of denudation 
 are traversed here and there by belts of more sharply 
 crumpled rock which give pause to the periodically encroach- 
 ing seas. More than one such system of plications has pro- 
 duced the frilled edge of western Europe with its association 
 of harder and softer rocks and has thus formed the natural 
 breakwaters which have held back for untold ages the 
 tremendous billows of the Atlantic Ocean hurled against 
 them by the South- West winds. In tracing the progress of 
 English Geology by reference to the lives of those who have 
 done most to promote it we shall soon find that it was seldom 
 mere accident that started them on their way. 
 
 We cannot satisfactorily discuss the influence of indivi- 
 duals upon Geological discovery without realising that 
 
William Smith 309 
 
 and's place on the globe and consequent geographical 
 ;res have made her a Geological microcosm in which 
 almost every known formation is represented in some part 
 of the surface, and that the secrets of her structure and history 
 are best disclosed in the mountainous regions of Scotland, 
 the Lake District, and Wales, rather than in the less disturbed 
 and more regularly disposed strata of the eastern and southern 
 counties. It has thus been in the more complicated regions 
 of the north and west that most of her prominent geologists 
 have been born or have found the sphere and stimulus of their 
 investigations. 
 
 Many a surveyor had observed the obvious fact that as 
 we proceed across the country various kinds of rock appear 
 at the surface one after another, and these have been laid 
 down on plans and maps for economic purposes; but the 
 careful work and shrewd intelligence of William Smith 
 (1769-1839), in the beginning of the nineteenth century, 
 led him to infer that these did not lie side by side like the 
 pieces in a Chinese puzzle, but rested on one another like 
 the tiles on a roof in regular succession, and that older rocks 
 crept out below the newer layers in a constant order. Here 
 we had the principle and mode of succession of rocks once 
 and for all established. 
 
 This, however, was not all that we owe to William Smith, 
 for though fossils had been previously collected he now 
 discovered that different plants and animals which lived and 
 died and were buried in the rocks were characteristic of 
 different beds and were followed by different forms of life, 
 and that the difference in these fossil remains enabled him 
 to detect to which formation of the adjoining district an 
 isolated patch of rock was most related. 
 
 Here we find the recognition of a chronological sequence 
 of the stratified rocks and of the possibility of identification 
 by means of the organic remains contained in them. The 
 first account of this discovery that every bed contained 
 characteristic and peculiar fossils by which it could be 
 identified was issued in 1799 by William Smith, and in 
 1815 he embodied the results of his twenty years of obser- 
 vation in the field in the first Geological Map of England 
 and Wales and part of Scotland. His work appeared to 
 
310 Britain's Heritage of Science 
 
 Sedgwick of such fundamental importance that he called 
 Smith " the Father of English Geology." 1 The majority 
 of the names, Lias, Gault, Clunch, etc., which he applied 
 to the sedimentary formations in England, were only 
 names used by local workmen for certain kinds of deposit, 
 but they have been retained and are now the alphabet of 
 stratigraphical classification throughout the world. 
 
 As the work of examining the visible crust of the earth 
 proceeded men must often have raised the question how did 
 Nature bring about these vast changes ? 
 
 Dr. James Hutton (1726-1797), who in qualifying himself 
 for the Degree of Doctor of Medicine had familiarized himself 
 with the methods of scientific research, had many interesting 
 questions forced upon his notice in the cultivation of his estate 
 in Norfolk. These he attacked by strict inductive methods, 
 but the theory which has always been most especially asso- 
 ciated with his name and which now forms the foundation of 
 geological research relates to the manner of the building up 
 of the crust of the earth and the production of its subse- 
 quent modifications. These, he contended, had been brought 
 about by agents and processes still seen in active operation 
 somewhere on the earth, and in 1785 he communicated to the 
 Royal Society of Edinburgh these conclusions. John Playfair 
 (1748-1819), his pupil, published in 1802 his classic work 
 entitled " Illustrations of the Huttonian Theory of the Earth," 
 and demonstrated the igneous origin of granite and the work 
 of the agents of erosion in the production of scenery. It often 
 happens that a disciple of the originator of a new idea says 
 and writes more in defence of the theory than the original 
 author himself. We heard more about evolution from 
 Huxley than from Darwin. 
 
 Many fierce controversies arose around and about the 
 principal matters in dispute between Huttonians and Wer- 
 nerians as to the relative importance of fire and water in 
 geological phenomena, all of which have had the useful effect 
 of turning men to seek facts from Nature in support of their 
 own several views. 
 
 The school of Catastrophists which had indulged in wild 
 
 1 Proc. Geol. Soc., Vol. 
 
' 
 
 
 i 
 
 Charles Lyell 
 
 From a daguerreotype by J. E. Mayal 
 
J. Hutton, J. Play fair, C. Lyell 311 
 
 speculations on the causes of changes in the earth's physical 
 and organic history had their fallacies exposed by the work 
 of the successors and followers of Hutton and Playfair. For 
 from the seed sown on English soil by these two pioneers 
 sprang the sound healthy tree of Uniformitarianism throwing 
 out many branches brightened often by the flowers of genius 
 and eloquence, laden with the rich fruit of patient research 
 and honest criticism, sometimes warped by opposing acci- 
 dents but always deep-rooted and sound at the core. Many 
 a good workman helped to till the soil, but one name stands 
 out in bold relief over the entrance to the garden of English 
 Geology. Sir Charles Lyell (1797-1875) was a barrister who 
 turned to geology when he found that an increasing weakness 
 of sight prevented his following other pursuits for which he 
 had been more specially trained. Lyell is the man to whom 
 English Geology owes most. For half a century he supported 
 the Uniformitarian theory, training the growing plant, 
 checking unwholesome growths. Lyell watched the progress of 
 research into the modern changes of the earth and its inhabi- 
 tants, distinguished the true from the false, and dismissed 
 the evidence for that which was not yet proven. His great 
 work entitled " The Principles of Geology " was first pub- 
 lished in 1833, and its publication marks an epoch in the 
 history of Geology. 
 
 It is a long and winding way from the region of specu- 
 lation in which Werner and his disciples here and abroad 
 sought to find out how basalts were precipitated out of 
 an aqueous mixture, to the hardly won ground on which 
 Alfred Harker and his friends and pupils now urge with 
 persuasive accumulation of experiment and observation how 
 each ingredient was segregated according to its affinities 
 out of the eutectic magma which is now regarded as an 
 inferential fact. 
 
 Many strong men helped on the work, some, like 
 Dr. Samuel Allport about the beginning of the 70's, quietly 
 collecting material, others, like David Forbes, testing and 
 criticising and giving out freely in discussions from the vast 
 stores of knowledge thus acquired, others teaching and writing 
 like Teall, to whom we owe the first text -book on British 
 Petrography. 
 
312 Britain's Heritage of Science 
 
 Much of the research falls within the sphere of Chemistry, 
 but it is to the mi loscope and its accessories that we owe 
 most of the advances made. 
 
 Henry Clifton Sorby (1826-1908) may be regarded as the 
 pioneer along this line. He read a paper on the subject before 
 the Geological Society in 1857 describing the structure of 
 crystals as giving an indication of the origin of minerals and 
 rocks. These he studied by means of thin slices, a method 
 which he had previously, in 1850, applied to the study of 
 limestones. Sorby was followed by the Rev. Prof. Bonney, 
 an accomplished scholar and keen controversialist, who 
 grasped at once the value of these new instruments of 
 research, vindicated Sorby, and by his academic teaching 
 and writings brought the new methods into the prominent 
 and popular position which they now occupy. 
 
 " La paleontologie suive les marteaux 5>1 was a phrase in 
 which it was sought at a recent International Geological 
 Congress 1 to point out that it generally happened that the 
 collections of fossils which have furnished the materials for 
 comparative study or for the discrimination of important 
 series of strata owed their existence to the accident that they 
 were obtainable round the home of some keen investigator 
 who, working single-handed or gathering round him a band of 
 like-minded friends, had availed himself of his special oppor- 
 tunities. In this way all available exposures in the district 
 were well searched ; the strata were called after the localities 
 where they were first or best seen, and genera and species were 
 named after some one whom it was desired to honour or 
 some character that appeared distinctive. In offering a 
 comparative sketch of the development of stratigraphical 
 research in Britain we may take the names of the pioneers 
 alphabetically, chronologically, or topographically, and the 
 above considerations will soon convince us that a bio- 
 graphical sketch of the founders leads us at once to a con- 
 sideration of the locality in which their discoveries were 
 made. We can hardly select a better example in illustration 
 of this than the district round St. David's. Here the oldest 
 rocks in the British Isles were seen, folded and contorted it 
 
 1 Rept. International Geol. Congress, Petrograd, 
 
H. C. Sorby, H. Hicks 313 
 
 is true, but still revealing a definite order of succession among 
 the varieties of lithological character. There are there older 
 granitoid masses succeeded by overlying volcanic series. 
 Dr. H. Hicks (1837-1899), a young local medical practitioner, 
 attacked this difficult problem in the latter half of the 
 nineteenth century, and gave the latinized local names of 
 Dimetian and Pebidian to the two principal divisions. Pro- 
 fessor Bonney, E. B. Tawney, and others soon took up the 
 work and were in time able to draw up a sketch of the history 
 of that early metamorphic series. Similar rocks were dis- 
 covered elsewhere in the same position with reference to the 
 fossiliferous formations and, though differing in details, were 
 easily co-related with the typical series of St. David's. These 
 had been noticed by earlier stratigraphical geologists, but 
 were passed over with only a short description. There was, 
 however, little doubt about the Archaean Rocks (as they 
 came to be called) of North Wales, of the Midlands, where 
 they have been described by Callaway and others, and of 
 North -West Scotland, where a new difficulty was introduced 
 by the wondrous earth movements which left these as well as 
 some newer rocks folded, broken, displaced, and crushed, 
 often beyond recognition. The researches of Dr. Hicks and 
 his able exposition of his progressive views on the Archaean 
 Rocks are sufficient to prove what geologists owe to the 
 accident of his residence at St. David's; but there was yet 
 more left for him to discover. Resting upon the denuded 
 surface of the Archaean Rocks were the Basement Beds of 
 the Cambrian separated from the pre-Cambrian Rocks by 
 a vast interval of time. The Survey had passed over the 
 district without detecting any trace of fossils in these beds, 
 but Hicks resided there, and his hammer left little untried. 
 He found fossils in these early Cambrian beds and, incited 
 to closer search, he found them in lower and lower beds till 
 there was hardly any horizon from which he had not pro- 
 cured new species and new genera. This brought Salter, 
 one of the most acute of palaeontologists, to his side. These 
 unexpected discoveries are recorded in the name given to a 
 trilobite, seventeen inches long, which was called Paradoxides 
 Davidis, the specific name connecting it with St. David's. 
 The subdivisions in which these various forms occurred 
 
314 Britain's Heritage of Science 
 
 were named from the localities where they were first or best 
 revealed to the hammer of the geologist, and so the lists of 
 the earliest fossiliferous rocks and their fossils are filled with 
 names dear to the tourist and the artist. 
 
 The correlation of these by means of their fossils with 
 the rocks exposed in other areas rapidly followed, as, for 
 instance, by David Homfray, at Portmadoc, and soon the 
 unexpected Paradoxides and its associates were recognized 
 among the lowest beds of the fossiliferous rocks all the 
 world over. 
 
 Other systems were determined in course of time : the 
 home of T. T. Lewis (1801-1858), of Aymestry, is still marked 
 by the Aymestry Limestone, while the position of the Llan- 
 dovery Rocks as now defined by the Survey was determined 
 by Dr. Williams, of Llandovery. The Llandovery Rocks were 
 subsequently cut off from the Caradoc Sandstone, and their 
 true position correctly fixed by Sedgwick under the name 
 May Hill Sandstone. A region so full of promise as the 
 borderland of Wales attracted Sir Roderick Murchison (1792 
 1871), who, in the first half of last century, collated the 
 evidence and gave to the world in 1893, in his magnificent 
 work, the Silurian System beautifully illustrated by Sowerby. 
 The name Silurian is derived from the Silures of South Wales, 
 the ancient tribe which so long withstood the invading 
 Romans. 
 
 In the meantime Prof. Adam Sedgwick (1785-1873), 
 stimulated by the work of Jonathan Otley in Cambria, and 
 with a personal acquaintance from childhood with the rocks 
 of the North of England, was attracted by the charms of a 
 wild and almost unexplored country, and threw all his energy 
 into the work of unravelling the succession of stratified rocks 
 exposed hi the mountains of Cambria. His results were given to 
 the world in papers published by the Geological Society during 
 the same period and in other works in which the fossils were 
 figured and described by Salter and McCoy. It is to Sedgwick 
 that Geology owes the name Cambrian for the oldest known 
 group of fossiliferous rocks; and it was his genius which 
 introduced order into our knowledge of the older Palaeozoic 
 rocks of the North of England and W 7 ales, and laid the founda- 
 tions for subsequent work in the complicated regions where 
 
R. Murchison, A. Sedgwick, H. Delabeche 315 
 
 they are developed. Sedgwick 's influence on the modern 
 school of geologists is difficult to overestimate. 
 
 At the close of the Silurian Period there was an irregular 
 sinking of the land. The old surface was worn down and the 
 material for new lands built up from the products of the 
 waste. England was in the region of most constantly recurring 
 movements ; and it so happened that during the period that 
 now supervened the British Isles formed part of the margin 
 of Eurasia, in which there were more limited hydrographical 
 areas. In one place corals grew in bright clear water, while, 
 not far off, lagoons and swamps favoured the growth of a rich 
 semi-tropical vegetation, with a fresh or brackish water fauna 
 in which fish abounded. The beds with this later facies 
 received the name of Old Red Sandstone. Local geologists 
 were led to study the exceptionally rich deposits which 
 occurred near their homes, and thus the fishes of the Old 
 Red Sandstone in Scotland arrested the attention of Hugh 
 Miller, one of whose fascinating books was a description of 
 this formation. 
 
 Sir Henry Delabeche (1796-1855) was attracted to the 
 tongue of land which runs out to meet the Atlantic on our 
 south-west coast. He recognized that mapping, mapping, 
 mapping, was the chief essential for the understanding and 
 recording of the geological structure of a country. He long 
 worked single handed at the district, and published treatises 
 and memoirs which are still classic works. But his crowning 
 achievement was the establishment of the Government 
 Geological Survey, which has developed into a great school 
 of geological research, and proved the model on which all 
 similar institutions have been organized. 
 
 John Phillips (1800-1874), the Oxford Professor of 
 Geology, was born on the great rim of rocks which hold the 
 South Wales Coal field as in a basin. From its swelling hills 
 and crags it was called the Mountain Limestone, a name by 
 which it is still commonly known. Phillips was drawn away to 
 Yorkshire, where he soon found himself on the very same 
 Carboniferous rocks, on which, as well as on the secondary 
 rocks which succeeded them, he wrote admirable treatises. 
 
 The nomenclature followed the hammers of these leaders 
 of research, but now, alas, students cannot avail themselves 
 
316 Britain's Heritage of Science 
 
 as fully as they might of these geological classics, because 
 hardly any of the fossils retain the name originally assigned 
 to them. Names, instead of being regarded as a means of 
 recalling the forms referred to, have become a means of 
 forcing on the world new theories of classification which have 
 to be changed again when later authors are impressed by 
 the value of other similarities or differences. 
 
 In the working of coal mines and quarrying of limestones 
 of the Carboniferous formation opportunities are offered to 
 the hammers of the palaeontologists and stratigraphists to 
 follow the exposed rocks, and so we find the same story 
 repeated. Witham, Binney and Williamson collected the fish 
 and the plants from the coal measures near Manchester; 
 and Lindley and Hutton devoted their attention to the study 
 of the vegetable remains 
 
 At the close of the Carboniferous period there again 
 ensued a period of local destruction of older beds, followed 
 by the deposition of fresh rocks of the New Red Sand- 
 stone. Vast movements of continental masses were taking 
 place and hydrographical areas became still more limited 
 in extent and consequently more varied in their results. So 
 much, however, did they present a general uniformity 
 in the character of the sequence and in their prevailing 
 colour that these basement beds of this new system, 
 the so-called Poikilitic or Variegated series of Phillips, came 
 to be known as the New Red Sandstone. The lower part 
 gave rise to much controvers}^, as it was by some con- 
 sidered the equivalent of the Permian of Russia, and by 
 some bracketed with the underlying Carboniferous rocks. 
 Passing by these details of classification we find that the 
 study and nomenclature of these deposits in parts of England 
 were determined by the home of Charles Moore (1815-1881), 
 near Gloucester and Dr. E. P. Wright (1834-1910), at 
 Cheltenham. W. H. Fitton and G. A. Mantell in the South 
 of England elucidated the sequence of relations of the Jurassic 
 and Cretaceous beds and utilized their local opportunities of 
 adding to our geological knowledge of these formations and 
 their fossils. 
 
 Thus we see that biographical notices of the early geo- 
 logists carry us to their homes round which the recreations of 
 
Palaeontology 317 
 
 leisure hours enabled them to work out in detail the succession 
 of the rocks and the distribution of their organic remains. 
 The names attached to the formations and now in common 
 use throughout most of the world prove that England has 
 contributed most largely to the establishment of the sequence 
 of events in the earth's history and to laying the foundations 
 of a rational system of classification of the strata. 
 
 Amongst the Tertiary rocks Sir Joseph Prestwich (1812- 
 1896) and Edward Forbes (1815-1854) traced the succession 
 of beds particularly in the London and Hampshire basins 
 and demonstrated the value of the now generally adopted 
 terms Pleistocene, Pliocene, Miocene and Eocene which Lyell 
 had first applied early in the last century. 
 
 Much good work has been done by British Palaeonto- 
 logists apart from the collecting of fossils in the field, where 
 Palaeontology is the handmaid of Stratigraphy. 
 
 For instance, Thomas Davidson (1817-1885) during the 
 last decades of the nineteenth century was examining and 
 comparing the Brachiopoda which played so large a part in 
 the life-history of the older rocks, while field geologists far 
 and near sent up to him the results of what their hammers 
 had yielded, thus supplying him with more and more material 
 and availing themselves of his every ready and untiring 
 help to discriminate between zones by means of their fossils. 
 
 Edwards and Haime did the same for corals. J. W. Salter 
 (1820-1869) had established many of the recognized genera 
 of trilobites in the course of his investigations of the faunas 
 of the older rocks between the years 1840 and 1855. 
 McCoy's labours covered a wide field, but his chief work lay 
 amongst the fossils of the older rocks. To James de Carle 
 Sower by (1787-1871) we owe many of the names of fossils 
 which have a cosmopolitan distribution. Sir Richard Owen's 
 (1804-1892) researches amongst fossil vertebrates gained him 
 the reputation which was due to his remarkable acumen and 
 minute knowledge of anatomy. 
 
 While pointing out where, how, and why British geologists 
 were pressing on special research we must not forget those 
 who, having acquired wide and accurate knowledge of many 
 branches, have collected and sifted the evidence and given 
 the results of their labours in the form of text-books, and 
 
318 Britain's Heritage of Science 
 
 memoirs to which students may turn for the latest and most 
 up-to-date views on each advancing front. Here we must 
 mention the two Geikies. Dr. James Geikie (1839-1915), 
 besides valuable memoirs on general geology, has given us 
 a summary of the arguments in favour of a correlation of 
 astronomical cycles with geological periods. Sir Archibald 
 Geikie has in text-book after text-book met the wants of 
 every age, and, in the clear and attractive language which 
 Scotsmen seem to have by nature, or to have evolved the 
 method of acquiring by education, has kept generations of 
 students supplied with accurate information as to the state 
 of the evidence on the many questions raised in the progress 
 of an advancing science. 
 
 This may be called an age of text-books, many of them 
 entitling their authors to a foremost place among those 
 who are helping on the progress of science, but we cannot 
 here even give a list of their names. 
 
 We are too apt to attach such importance to our modern 
 theories that we forget what a great advance an earlier 
 hypothesis had often made on pre-existing views. It was a 
 shrewd observation which induced the clever and courageous 
 Dean Buckland (1784-1856) to maintain that a large part 
 of the superficial deposits which are seen heaped up on the 
 tops and flanks of the highest hills and filling the deepest 
 valleys of the North of England must have had an entirely 
 different origin from the alluvial deposits such as we see 
 being laid down now, and to venture on the bold suggestion 
 that there had been in quite recent times a great sub- 
 mergence and that the sea once swept over the land and left 
 as the result of the deluge these tumultuous deposits hence 
 called Diluvial. 
 
 Wider travel and more detailed work, however, showed 
 a closer analogy between most of these so-called Diluvial 
 formations and the masses of debris carried on, in, or under 
 the ice and left at its foot when the glaciers or ice sheets 
 melted. Agassiz pointed this out and a grand company of 
 Scotch and other geologists immediately set to work on the 
 details of every section to prove or disprove the truth of 
 each new suggestion. 
 
 In the domain of Economic Geology William Smith's 
 
Economic Geology 319 
 
 observations were primarily connected with the question 
 of soils; while Farey's descriptions in 1811 and 1813 of the 
 Derbyshire Coal Measures and lead mines and of the dis- 
 location of the strata were of practical value. To questions 
 of water-supply Prestwich's attention was specially drawn, 
 and the possible extension of the Coal Measures beneath the 
 South-East of England was maintained as far back as 1855 
 by Godwin Austen, whose geological conclusions have now 
 been verified. 
 
 The energy of geologists still living amongst us does not 
 slacken and the reputation of British workers in this branch 
 of science is well maintained, while the application of the 
 results of geological research to economic purposes is having 
 an ever-increasing stimulus given to it. 
 
INDEX 
 
 (Where proper names occur more than once, the principal entry, generally 
 containing a short biographical notice, is printed in italics) 
 
 PAGE 
 
 Abel, Sir F. - 199,202 
 
 Abernethy, J. - - 264 
 
 Aberration of light - 62, 70 
 
 Abney, Sir W. - - 160, 173 
 Absorption, spectrum analy- 
 sis - - 155-9 
 Academie des Sciences 97, 1 15, 120 
 Achromatism of lenses 98, 99 
 Acoustics, see under Sound. 
 Adami, J. G. - - 301, 306 
 Adams, J. C. - 125-7 
 Addison, T. - - 300 
 Aeronautics : 
 
 First hydrogen balloon 68 
 Glaisher's balloon as- 
 cents - - 176 
 Roy's experiments - 307 
 Agassiz - - 318 
 Agriculture - - 252,253 
 Air: 
 
 Boyle's law - 75 
 
 Composition of - 85 
 
 Liquid - - 213 
 
 Airy, Sir G. B. - - 70, 119, 126 
 Astigmatism - - 120 
 Organization of observa- 
 tories - 165 
 Aitken, J. - 176 
 Alizarin colours - 163, 200 
 Alkali, manufacture of - 194 
 Allman, G. J. - - 282 
 Marine research - - 292 
 AUman, Prof. W. - - 254 
 Allport, S. - 311 
 Alluvial deposits - - 318 
 Alpha particles - - 184 
 Anaemia, pernicious, dis- 
 covery of - - - 300 
 Analytical Society - - 117 
 Anaxagoras - - 14 
 Anaximenes - " - - 8 
 
 PAGE 
 
 Andrews, T. - - 139, 140 
 Angout, A. 95 
 
 Aniline dye discovered 200, 201 
 " Animal " electricity - 106 
 
 Anti-septic surgery - - 306 
 Apjohn, J. - - - 176 
 
 Arago - - 19,119,126,140 
 Archer, F. S. - - 173 
 
 Archibald, E. D. - - 176 
 Arctic expeditions, see under 
 
 Expeditions. 
 
 Argon, discovery of - - 181 
 Aristotle - - 14,216 
 
 Arrhenius - 146 
 
 Asclepiadeas - - 244 
 
 Ashmole, E. - - 261 
 
 Ashmolean Museum, founda- 
 tion of - 261 
 Astigmatism, discovery of 120, 300 
 Atom - - 14 
 Atomic Theory - 15 
 Numbers - - - 185 
 Austen, G. - 319 
 Ayrton, W. E. - - - 193 
 
 Babbage, C. 
 Bache, Dr. 
 Bacon, F. 
 Bacon, R. 
 Baily, F. - 
 
 117,118 
 
 - 159 
 
 - 223 
 
 7,8,218 
 162, 208 
 
 Baines, Sir 1., footnote - 295 
 Balloons - - - 68,176 
 Balfour, F. M. - 277, 284, 301 
 Balfour, J. H. - - 254 
 
 Banks, Sir J. - 116, 241, 243 
 
 Founding of Royal In- 
 stitution - - 213 
 
 Agricultural research - 238 
 Barrow, I. ... 49 
 
322 
 
 Index 
 
 PAGE 
 
 Barclay, J. - 265 
 Bartolomaeus Angelicus - 217 
 
 Basement membranes - 300 
 
 Bateman, S. - 217 
 
 Be"champ - - 200 
 
 Becquerel, H. - - 183 
 
 Beddoes, T. - - 110 
 
 Bell, Sir C. - 306 
 
 Bennett, A. - 80 
 
 Bennett, C. - - - 173 
 
 Ben Nevis Observatory - 176 
 
 Bentham, George - 245, 246 
 
 Berkeley, M. J. - - 250 
 
 Bernard, E. 49 
 
 Bernoulli, Daniel - - 33 
 
 Berryman, Lieut. - - 291 
 
 Berzelius - 150 
 
 Bessemer, Henry - - 187 
 
 Beta particles - - 184 
 
 Bevis, J. - - , - 81 
 
 Binney, E. W. - - 316 
 
 Biometrics - - 286 
 
 Bird, J. - - 97 
 Birmingham University - 160 
 Black, J. - -14,55-^,130,299 
 
 Bleaching - 195 
 
 Bliss, N. - - 63 
 Blood: 
 
 Circulation of - - 294 
 Coagulation of - 299, 305 
 Pressure, first estimates 298 
 Transfusion of, dis- 
 covery - - - 297 
 Bolton, W. B. - - 173 
 " Bone-digester " - - 101 
 Bonney, T. G. - - 312,313 
 Boscovich - - 70 
 Botany - - 229-255 
 Cryptogamic - - 250 
 Boulton, M. - - 103 
 Bouvard, A. - 126 
 Bowman, Sir W. - 300 
 Boyle, R. - - 1 4, 73-6, 124,288 
 Boyle lectures - - 74 
 Boyle's law - 75 
 Boys, V. - - 87 
 Bradley, J. - - 61, 70, 97 
 Bragg, W. - - - 184 
 Brahe, Tycho ? 5? 
 
 PAGE 
 
 Brain, circle of Willis, dis- 
 
 covered - 
 
 - 297 
 
 Bramah, J. 
 
 - 105 
 
 Bramah lock 
 
 - 105 
 
 Brande, W. T. - 
 
 39, 198 
 
 Brewster, D. - 69, 
 
 119, 124, 
 
 
 131, 156 
 
 Briggs, H. 
 
 - 48 
 
 Brinkley, J. 
 
 - 136 
 
 Brisbane, T. 
 
 - 253 
 
 British Association 
 
 132, 214 
 
 British Museum 
 
 266, 267 
 
 Brouncker, Lord 
 
 - 51 
 
 Brown, Crum 
 
 - 133 
 
 Brown, R. 
 
 243, 255 
 
 Brownian movement - 
 
 - 244 
 
 Brunner & Mond 
 
 - 198 
 
 Buchan, Alexander 
 
 - 176 
 
 Buchanan, J. Y. 
 
 - 291 
 
 Buckland, W. - 
 
 - 318 
 
 BufTon 
 
 - 262 
 
 Bunsen - - 149, 
 
 150, 157 
 
 Cables, submarine - 189, 190, 
 291, 292 
 
 Caius, J. - - 219,257 
 
 Calculus - - 53 
 
 Cambrian formation - - 314 
 " Canon Mirificus " 7 
 
 Canton, John - - 80, 205 
 Capillaries, discovery of - 294 
 Capillarity - 83, 131 
 
 Carbonic acid, discovery of 66 
 
 Condensation of - - 140 
 Carboniferous formation - 316 
 Cardio-myograph - - 306 
 Cardiac-plethysmograph - 306 
 Carlisle, Sir A. - - 107 
 
 Carnot, Sadi - - 27, 29 
 Carpenter, W. B. - - 289 
 Castner - - 194 
 
 Castner-Kellner process - 198 
 Catalytic action - 146 
 
 Cauchy - - 122 
 
 Cavendish, Lord C. - - 83 
 
 Self -registering thermo- 
 meters - - - 288 
 
Index 
 
 323 
 
 PAGE 
 
 Cavendish, Henry 14, 69, 73, 83-6 
 Density of earth - 87 
 
 Law of inverse square- 81 
 Meteorological observa- 
 tions organized - 208 
 Cawley - - 101 
 
 Cayley, A. - 128, 129 
 
 Cells, nucleus of - 244 
 
 Challis, James - - 126, 127 
 Chambers, R. - - 275 
 
 Chance, Messrs. - 172 
 
 Charles II., interest in 
 
 science - - 57, 203, 227, 233 
 Chemical Society - - 212 
 Chemistry, industrial appli- 
 cation - - 194-202 
 Chloroform, discovery of - 305 
 Action on heart - - 303 
 Chrystal, G. - 133 
 Christy, S. H. - - 147 
 Chronometer - 96 
 Chromosphere, spectrum of 171 
 Ciliary apparatus of eyeball 300 
 Circle of Willis - - 297 
 Circles, divided - 96, 97 
 Circulation of blood - - 294 
 Clarke, A. R. - - 176 
 Clausius, R. - - 28 
 Clifford, W. K. - - - 147 
 Clift, W. - - - - 265 
 Clifton, R. B. - - 151 
 Clocks : 
 
 Anchor escapement - 95 
 Temperature compen- 
 sation - - 96 
 Coagulation of blood - 299, 305 
 Coal-tar industry, history of 
 
 199-201 
 
 Cobbett, L. - - 306 
 
 Coherer - - 191 
 
 Coke tower condenser, in- 
 vention of - 197 
 Colloids - - 145 
 Colour : 
 
 Dispersion - -54, 98 
 
 Photography - - 173 
 Thin plates - 19 
 
 Vision - - 128, 300 
 Comet, Halley's - . 59 
 
 PAGE 
 
 Common, A. A.- - - 170 
 Compass : 
 
 Early knowledge of 3 
 
 Improved by Airy - 121 
 
 Conductivity, see under Heat. 
 
 Conservation of energy 8, 22, 135 
 
 Cooke, Sir W. F. - 188 
 
 Cooper, A. - 264 
 
 Coral - 317 
 
 Cordite - - 202 
 
 Corporation of Surgeons - 265 
 
 Corpuscular theory of light 17 
 
 Cotes, R. - 56 
 
 Coulomb - 69, 70 
 
 Courtois - - - 115 
 
 Crabtree, W. - - 88, 89, 95 
 
 Crawford - - 131 
 
 Critical temperature - 140 
 
 Crookes, Sir W. - - 151,199 
 
 Electric discharge - 181 
 
 Radiometer - 180 
 
 Thallium, discovered - 159 
 
 Cruikshank - - 113 
 
 Cryptogamic botany - - 250 
 
 Crystalline structure - 130, 312 
 
 Crystallography - 130 
 
 Cugnot, N. - - 104 
 
 Cullen, William - - 65 
 
 Curie, M. and Mme. - - 183 
 
 Cuvier - - 115, 265, 282 
 
 On organization of Royal 
 
 Society - - - 212 
 
 Daguerreotype - 
 
 - 173 
 
 Dalton, J. 
 
 - 15, 36, 40 
 
 Daniell, J. F. - 
 
 - 147 
 
 Darwin, C. 
 
 267-281, 286, 
 
 
 246, 248 
 
 Darwin, E. 
 
 - 268, 274 
 
 Darwin, F. 
 
 - 236 
 
 Darwin, G. H. - 
 
 - 177, 178 
 
 Darwin, R. W. - 
 
 - 268 
 
 Daubeny, C. G. - 
 
 - 251 
 
 Davidson, T. 
 
 - 317 
 
 Davy, Sir H. - 
 
 21, 37, 109, 172, 
 
 
 210, 213 
 
 X2 
 
324 
 
 Index 
 
 PAGE 
 
 Davy's lamp - - 116 
 
 Deacon, H. - 198 
 " De Different/us Animal - 
 
 ium" - - 257 
 
 Degradation of energy - 30 
 
 Delabeche, Sir H. - - 315 
 
 Delambre 60, 63 
 
 De la Rive - 39 
 
 DelaRue, W. - - 169 
 
 De la Tour, C. - - 140 
 
 Deluc - - 66 
 
 De Mayerne, Sir T. T. - 296 
 
 Democritua - 14 
 
 De Morgan, A. - - 143 
 
 Desaguliers, J. T. - - 71 
 Descartes, R. - - 12, 49, 120 
 Dewar, Sir J. : 
 
 Cordite, invention of - 202 
 Liquefaction of gases 140, 213 
 Solidification of hydro- 
 gen - 146 
 Spectrum analysis - 159 
 Diamond, nature of - - 115 
 Differential calculus - 49, 53 
 Notation - - 117 
 Diffraction - 19 
 Digby, Sir K. - - 225 
 DiUenius, J. J. - - 251 
 Diluvial deposits - 318 
 Dispersion of colours- 58, 98 
 Dissipation of energy - - 29 
 Dodo - 261 
 Dollond, J. - 98, 205 
 Dryander - - 242, 244 
 Dufay - - 79 
 Dyeing industry 194, 199-201 
 Dyer, G. - - 197 
 Dynamo machine - 192, 193 
 
 Earth: 
 
 Density of - 
 Tremors 
 
 Earthquakes 
 
 Ebonite - 
 
 Edwards, A. M. 
 
 - 64, 86, 87 
 
 - 214 
 
 - 88 
 
 - 190 
 140, 292, 317 
 
 PAGE 
 
 Electric arc - - 114 
 
 Battery - 106, 147, 163 
 
 Spark - 78 
 
 Telegraph - - 187-189 
 
 Theories 31, 33, 79, 81, 182 
 
 Units - - 214 
 
 Electricity, atmospheric - 205 
 
 Conduction of - -71,78 
 
 Discharge through gases 78, 
 
 85, 182 
 
 Early researches 5 
 
 Frictional - -80,81 
 
 in Fishes - - 83 
 
 Industrial applications 
 
 of - - - 187-194 
 
 Law of inverse squares 69, 81 
 
 Medical applications - 300 
 
 Electrolysis - - 21, 107 
 
 Electrolytic production of 
 
 metals - - 113 
 
 Electro -magnet, invention of 148 
 Electro -magnetic : 
 
 Induction - - 20, 191 
 Theory of light - 32, 138 
 Electro -magnetic engine - 24 
 Electrometer - 70 
 
 Electron theory 138, 139, 182 
 
 Electroscope, gold leaf - 80 
 Electrostatics - - 31, 81, 82 
 Ellis, Capt. - 288 
 
 Embryology - - 284, 295 
 Energy : 
 
 Conservation of 8, 22, 28, 135 
 Dissipation of - 29, 30 
 
 Kinetic - - 23 
 
 Potential - 23, 123, 135 
 Transmission of - - 161 
 Engine : 
 
 Dynamo - - 192 
 
 Electro -magnetic - 192 
 
 Steam - 99-105 
 
 Ent, Sir G. - 226 
 
 Erosion, geological effects - 310 
 Eskdalemuir observatory - 209 
 Eugenics - - 277, 280, 286 
 Euler - - 98 
 
 Evelyn, J. - 220, 225, 226 
 
 Evaporation, cooling pro- 
 duced by - - 65 
 
Index 
 
 325 
 
 Ewing, J. A. 
 Expeditions : 
 
 Antarctic - 
 
 Arctic 
 
 Beacon 
 
 Beagle 
 
 Bulldog 
 
 PAGE 
 
 - 193 
 
 247, 288 
 207, 288 
 
 - 289 
 
 - 271 
 
 - 291 
 
 Central America, God- 
 
 man and Salvin . - 293 
 Challenger - 283, 290, 291 
 Cyclops - - - 291 
 Endeavour 241, 242 
 Erebus - - 247, 289 
 Lightning - - 289 
 
 Porcupine - - - 289 
 Racehorse - - 207 
 
 Rattlesnake, Huxley - 282 
 
 Foucault - 
 Fownes, G. 
 Fox, W. D. 
 Frankland, E. - 
 Franklin, B. 
 Franklin, Sir J. - 
 Fraunhofer 
 Freezing mixtures 
 
 PAGE 
 
 - 156 
 
 - 146 
 
 - 270 
 148, 149 
 
 79, 205 
 
 - 289 
 155, 156 
 
 - 76 
 
 Freezing point, influence of 
 
 pressure - 136 
 
 French Academy of Science - 97, 
 
 115, 210 
 
 Fresnel, A. J. - 19, 20, 54, 119, 
 
 122, 137 
 
 Fry, P. W. - - 173 
 
 Falconry - 258 
 
 Faraday, Michael : 
 
 Electro -magnetic induc- 
 tion, discovery of 20, 31, 
 37,43, 191, 198,213 
 Inductive capacities - 82 
 Optical glass - - 205 
 Farey - - 319 
 
 Fibrinogen - 299 
 
 Fire-damp - - 115 
 
 Fitton, W. H. - - 316 
 
 Fitzgerald, G. F. - 137, 138 
 Fitzroy, Capt. - - 271 
 
 Fizeau - - 132 
 
 Flamsteed, J. - 67 
 
 Fleming, A. - - 257 
 
 Flora : 
 
 Australiensis - - 246 
 
 Colonial - - 247 
 
 of Hong Kong - - 246 
 
 Indica - 248 
 
 Flower, Sir William - 267, 283 
 
 Fluorescence - - 124 
 
 Fluxions - - 35, 53, 117 
 
 Forbes, E. - - 289, 317 
 
 Forbes, J. D. - 132, 136, 311 
 
 Fossils - - - 309, 312 
 
 Foster, Sir M. - 250, 300, 304 
 
 on F. M. Balfour - 285 
 
 Galileo - 
 
 Galen 
 
 Gadow, H. 
 
 Galitzin, Prince 
 
 Galle 
 
 Galton, Sir F. - 
 
 Galvani, L. 
 
 Galvanism 
 
 Gamble, J. C. 
 
 5,8,9 
 216, 219 
 
 - 284 
 
 - 179 
 
 - 127 
 277, 286 
 
 - 106 
 
 - 112 
 194-197 
 
 Gas, illuminating, first used - 105 
 Gay-Lussac - - 37, 115 
 Gassylvestre - - 66 
 
 Gascoigne, W. - 57, 94 
 
 Gases : 
 
 Diffusion of 145 
 
 Kinetic theory of - 33 
 Liquefaction of 139, 212, 213 
 Transpiration of - - 145 
 Viscosity of - 34 
 
 Gaskell, W. H. 301, 302, 303, 304 
 Gassiot, J. P. - - 162, 209 
 Geikie, Sir A. - - - 318 
 Geikie, J. - 318 
 
 Geissler tubes - - 162 
 
 Gellibrand, H. - - 58 
 
 Geodetical Survey - - 207 
 Geological Society - - 212 
 Geological survey, Govern- 
 ment - - 315 
 Geology - - 308-319 
 
326 
 
 Index 
 
 PAGE 
 
 Geometry, analytical - - 49 
 Geo -physics - - 133 
 
 Gerard, J. - 229, 231 
 
 Gesner, C. 220, 256, 257, 258 
 
 Gilbert, W. - - 3 
 
 Gill, Sir D. 166-8 
 
 Glaciers - - - 133, 136 
 Glaisher, J. W. L. - - 141 
 Glaisher, James - - 176 
 
 Glass: 
 
 Optical - 81, 168, 205 
 Glazebrook, Sir R. - - 210 
 Glisson, F. - 297 
 
 Glover, J. - 198 
 
 Godman, F. D. - - 293 
 
 Goodsir, H. - - 289 
 
 Goodyear, C. - - - 190 
 Gordon, R. M. - - - 173 
 Gossage, W. - - 197 
 
 Gosse, P. H. - - 290 
 
 Gout - - 297 
 
 Graebe - - 200 
 
 Graham, G. - 95, 97 
 
 Graham, T. 68, 144, 145, 202, 254 
 Granite, igneous origin - 310 
 Gravitation 10, 11, 53, 64, 86 
 Gray, Stephen - 78 
 
 Greaves, J. - - - 49 
 Green, G. ... 121 
 
 Greenwich Observatory - 57, 
 165, 207, 208 
 Greenwich time, automatic 
 
 transmission of - - 166 
 Gregory, family of - 52 
 
 Gregory, D. - 52, 98 
 
 Gregory, J. - 52 
 
 Gresham, Sir T. 47 
 
 Gresham College - 46, 47, 203 
 Greville, R. K. - - - 254 
 Grew, N. - - - 232, 234 
 Grove, W., Lord Justice - 163 
 Guericke's air-pump - 75 
 
 Guillim, J. - - - 221 
 Gunter .... 94 
 
 Hadley, J. 
 Haime 
 
 - 95 
 
 - 317 
 
 PAGE 
 
 Hales, S. - 204, 236, 255, 
 
 288, 298 
 
 Hall, C. M. - 99 
 
 Halley, E. - 58-60, 92 
 
 Halley's comet - 59 
 
 Hamilton, Sir W. R. - - 136 
 Hamilton's principle - - 136 
 Hancock, T. - - 190 
 
 Harcourt, V. - - 141 
 
 Barker, A. - 311 
 
 Harris, Sir Snow - 205 
 
 Harrison, J., chronometer 69, 96 
 Hartley, W. - 160 
 
 Harvey, W. - 219, 223, 294 
 Haughton, T. - - 137 
 
 Havers, C. - - - 298 
 Hauksbee, F. - 77, 78 
 
 Heart : 
 
 Structure of - 297, 303 
 Cardiac -plethysmograph 
 and cardio -myo graph, 
 invented - - 306 
 
 Heat: 
 
 Conductivity of - - 133 
 Equivalent of 26 
 
 Latent - 66, 86 
 
 Mechanical theory of - 25, 
 29, 108, 135 
 
 Polarization of - - 133 
 
 Radiation of - 76, 93, 
 
 131, 152, 158 
 
 Radiations - - 93 
 
 Specific, method of cool- 
 ing- - 131 
 Heliometer - - - 168 
 Helium - - 171, 181, 184 
 Liquefaction of - - 214 
 Hemming, J. - - 198 
 Henley, W. ... 80 
 Henry, T.- - - 148 
 Henry, W. - 148 
 Henslow, J. - - 253, 270 
 Heraclitus - 8 
 Heraldry - - 221 
 Herapath - - 33 
 Herbert of Cherbury, Lord 
 
 220, 225 
 
 Herbert, J. - 267, 274 
 
 Heredity, Mendelian theory 278 
 
Index 
 
 327 
 
 PAGE 
 
 Horschel, Sir John - 118,124, 
 156, 166 
 
 Hyposulphite, in photo- 
 graphy - - 173 
 Coloured flames - - 153 
 Optical glass manufac- 
 ture - - 205 
 Herschel, Sir W. 88, 90, 126, 169 
 Discovery of Uranus - 91 
 Finger-prints - - 286 
 Infra-red rays - 93 
 Star drifts 93 
 Hicks, H. - 313 
 Hieroglyphics, Egyptian - 37 
 Hill, E. - - 254 
 Hippocrates - - 216, 297 
 " History of Fishes " - - 259 
 " Historie of Foure -Footed 
 Beastes " and " Historie 
 of Serpents " - 220, 258 
 " History of Insects " - 259 
 Hofmann, A. W. 194, 199, 201 
 Holland, P. - - 217 
 Homfray, D. - - 314 
 Hooke, R. - 17, 55, 77, 259 
 Anchor escapement - 95 
 Mechanical theory of 
 
 heat 
 
 Pepys on - 
 
 Waller on - 
 
 Hooker, Sir J. D 
 
 Hooker, Sir W. J. 
 Hope, J. C. 
 Hopkinson, J. - 
 Hornblower, J. 0. 
 Horrocks, J. 
 Horse -power, first 
 
 term 
 
 Horticultural Society - 
 Howard, Henry (Duke 
 
 Norfolk) 
 Howard, L. 
 Hudson, Dr. 
 Hughes, D. 
 Huggins, Sir W. 
 Humboldt 
 Hume, D. 
 Hunter, J. 
 
 - 108 
 
 - 227 
 
 - 259 
 
 - 247, 255, 
 
 279, 289 
 
 - 246 
 
 - 130, 131 
 
 - 193 
 
 - 105 
 S, 89, 95, 207 
 use of 
 
 of 
 
 104 
 245 
 
 - 210 
 
 - 176 
 
 - 290 
 
 - 190 
 
 - 171 
 
 - 244 
 
 - 65 
 263-5 
 
 PAGE 
 
 Hunter, W. - - 263 
 
 Huntsman, Benjamin - 187 
 
 Hussey, J. T. - - 126 
 
 Hutton, C. - 64, 70, 86, 87 
 
 Hutton, James - 70, 245, 310, 316 
 Huxley, T. H. - 249, 279, 282, 
 291, 301 
 
 on Darwin - - 267, 278 
 
 on Owen - 265 
 
 Huygens, C. - 9, 17, 51, 95, 
 
 210, 211 
 
 Hydraulic press - 105 
 
 Hydrogen, generated by 
 
 electrolysis - - - 107 
 
 Solidified - - 214 
 
 Hydrogenium - - - 145 
 
 Hysteresis - 193 
 
 Illuminating gas, first used - 105 
 Infra-red rays, Herschel - 93 
 Ingenhouse, Dr. - - 81 
 
 Inoculation - - 204, 306 
 Instruments, scientific, con- 
 struction of - - 94, 95 
 Interference of light - 
 Integral calculus - 53, 117 
 Inverse square, law of, in 
 gravitation - - 10, 53 
 In electricity - 69, 81 
 Iodine, discovery of - - 115 
 lonization - - - 146 
 Ireland, Royal Society of, 
 
 Dublin - 
 
 Irish Academy of Sciences - 211 
 
 Irish universities, botany at 254 
 
 Physical science at - 137 
 
 Irvine - - - - 67 
 
 Jack,W. - 
 Jail fever - 
 Janssen - 
 
 - 151 
 
 - 204 
 
 - 171 
 
328 
 
 Index 
 
 Jeffreys, G. 
 Jellett, J. H. 
 Jenkin, F. 
 Jenner, E. 
 Jenyns, L. 
 Joly, C. J. 
 John of Trevisa 
 Johnson, Thomas 
 
 PAGE 
 
 - 289 
 
 - 137 
 
 - 292 
 264, 306 
 
 - 271 
 137, 174 
 
 - 217 
 
 - 231 
 
 Joule, J. P. 23, 28, 31, 40, 191 
 Equivalent of heat - 26 
 Velocity of molecules - 33 
 
 Journal of Physiology - 302 
 
 Kanthack, A. - .,, - 306 
 
 Kater, Capt. H. . 174 
 
 Kater's pendulum - - 175 
 
 Kelland, P. - _ 234 
 
 Kelvin, Lord (W. Thomson) 42, 
 
 123, 127, 134, 136 
 
 Appreciation of Joule - 41 
 
 Economics of dynamo 
 
 engine - - 192 
 Electric replenisher - 80 
 Second law of thermo- 
 dynamics - 28 
 Submarine cables - 189 
 Kennett, B. - 173 
 Kepler - - 8, 10, 53 
 Hew Observatory - - 209 
 King, J. - - 173 
 King's College, London, 
 
 foundation - - - 143 
 
 Kircher - - - 124 
 
 Kirchhoff - - - 157 
 
 Kite, meteorological - - 176 
 
 Klingenstjerna - - - 93 
 
 Knight, T. A. - - 238 
 
 Krypton, discovery of - 181 
 
 Lacteal vessels in birds, dis- 
 covery of 299 
 Langley, J. N. - - 299, 301 
 Lankester, Sir E. R. . 250, 278, 
 287, 288 
 
 PAGE 
 
 Laplace - - 20, 123 
 
 Larmor, Sir J. - - - 182 
 Lassell, W. - - 169 
 
 Latent heat, see under Heat. 
 Laughing gas - - 110 
 
 Lavoisier - - 14, 55 
 
 Leblanc - 194, 196, 197, 198 
 Lee, S. H. - 301 
 
 Leeds University - - 160 
 Legh, G. - - 221 
 
 Le Gray, G. - - 173 
 
 Leibnitz - - - - 117 
 Length and weight stand- 
 ards, reconstruction - 130 
 Leslie, J. - - 131 
 
 Leverrier, U. J. J. - 126, 127 
 Lexell - 91 
 
 " Liber de Proprietatibus 
 
 Rerum " _ 217 
 
 Liebermann - - 200 
 
 Life statistics - : - 60 
 
 Liebig, J. . - 199, 202 
 
 Light : 
 
 Aberration of - 62, 70 
 Conical refraction - 137 
 Corpuscular theory of - 17 
 Electro -magnetic theory 
 
 of - - 32 
 
 Fluorescence - - 125 
 Infra-red rays - - 93 
 Polarization - 19, 147 
 Refraction - 53, 81, 98, 121 
 Spectroscopy - 152-159 
 Wave theory 17, 18, 55, 56, 
 122, 123 
 
 Lighthouse illumination - 193 
 Lightning conductors - - 205 
 Lindley, J. - 245, 255, 316 
 Lindsay, Lord - - 167 
 
 Linnaeus - - 233, 239 
 
 Linnsean Society - 212 
 
 Lippmann, G. - - 173 
 
 Liquefaction of gases - 139, 213 
 Lister, Lord - - 306 
 
 Liveing, G. D. - - 159 
 
 Load-stone, origin of word - 4 
 Lockyer, Sir J. N. 159, 171, 181 
 Logarithms - - - 7, 48 
 Lloyd, H.- - - 137 
 
Index 
 
 329 
 
 PAGE 
 
 Lodge, Sir O. - -214 
 
 Locomotive, first - 104 
 
 Lower, Richard - -297 
 
 London, University of, foun- 
 dation - - 143 
 London - - 245 
 Lubrication, theory of - 151 
 Lumiere et Fils, colour 
 
 photography - - 174 
 
 Lyell, Sir C. 273, 279, 311, 317 
 Lymphatic vessels in birds, 
 
 discovery - - 299 
 
 Lyte, H. - - 230 
 
 Lyons, I. - - - 241 
 
 McCartney, J. - - - 264 
 McCoy - - - 314, 317 
 McCullagh, J. - - 122, 137 
 Maclaurin, C. - 56 
 
 Macleod, H. - - 199 
 
 Maddox, R. L. - - - 173 
 Magnetism, terrestrial 4, 120, 
 
 152, 209 
 
 Declination - 3 
 
 Diurnal variation - 95 
 
 Inclination - - 4 
 
 Secular variation - 58 
 
 Malpighi - - - - 255 
 
 Malthus, T. R. - - 274 
 
 Manchester University 148, 160 
 
 Mantell, G. A. - - 316 
 
 Marine biological stations - 293 
 
 Marine zones - - 289 
 
 Martin, N. - 250, 301 
 
 Martyn, T. 252 
 
 Maskelyne, N. - - 63, 86, 87 
 
 Mason College - - 161 
 
 Matthew, P. - - 274 
 
 Matter, atomic theory - 15 
 
 Electron theory - - 182 
 
 Maxwell, J. Clerk 8, 43, 44, 200 
 
 Electro -magnetic theory 
 
 of light 32 
 
 Kinetic Theory of G ases 34 
 
 On Cavendish* - 82 
 
 on second law of ther- 
 
 mo-dynamics - 30 
 
 PAGE 
 
 Mayow, J. 55, 225, 296 
 
 Medicine and surgery - - 262, 
 
 263, 306 
 
 Meldola, R. - - 201 
 
 Melville, T. - - 152 
 
 Mendel, G. - 277, 278 
 
 Mendelism - 280 
 
 Mercator's projection - - 48 
 Meteorology 147, 176, 208, 209 
 Michell, J. - 86, 87, 88 
 
 " Micrographia " - 55,260 
 Micrometer, invention of - 94 
 Double image - - 97 
 Microphone - - 191 
 
 Miers, Sir H. - - 181 
 
 Milky way - - 92 
 
 Miller, H. - 315 
 
 Miller, W. A. - - 164 
 
 Miller, W. H. - - 129 
 
 Milne, J. - - 178, 214 
 
 Milton, J. - - 220 
 
 Miner's lamp, invention of - 116 
 Moffett, T. - 219 
 
 Molyneux family - 89 
 
 Molyneux, Samuel - 61, 89, 90 
 Mond, L. - - . - 198 
 
 Moore, C. - - 316 
 
 Morse code - - 189 
 
 Morison, R. 232, 233, 234, 251 
 Moseley, H. N. - - 291 
 
 Moseley, H. - - 184, 185 
 Motion, laws of - 9 
 
 Mulgrave, Lord - - 288 
 
 Multiple proportion, law of- 16 
 Murchison, Sir R. - - 314 
 Murdock, W. - - 105 
 
 Murray, J. - 291 
 
 Muscle, striated - 300 
 
 Muspratt, J. 195, 196, 197, 198 
 
 Napier, John, of Merchiston 6 
 Nasmyth, James - 169 
 
 National Physical Labora- 
 tory - - 209, 214 
 Natural selection - 272, 274 
 
330 
 
 Index 
 
 PAGE 
 
 Nautical Almanac - 37, 63 
 
 Nautilus, Pearly - 265 
 
 Navigation, influence on 
 
 science - - 47, 63, 96 
 
 Nebulae - - 169, 170 
 
 Spectrum of - 172 
 
 Neon, discovery of - - 181 
 
 Neptune, discovery of 125-7 
 
 Neumann, F. - - 122 
 
 Newall, R. - 172, 189 
 
 Newcombe, S. - - 125, 126 
 
 Newcomen, T. - - 101 
 
 Newton, Sir Isaac - - 33, 
 34, 52, 76, 211 
 
 Fluxions - 35, 53 
 
 Gravitation 10, 11 
 
 Laws of motion - >- - jfc 
 
 Light - 53-56, 98 
 
 Tides- - .- ; - 177 
 
 Nicholson, E. C. -> . - 201 
 
 Nicholson, W. - -- 80, 107 
 
 " Nicholson's blue " - - 201 
 
 Nicholson's Journal - 107,111 
 
 Niepce, J. N. - - 173 
 
 Nitrogen, isolation of - - 68 
 
 Nitrous oxide - - 111 
 
 Noble, William - - 50 
 
 Norman, Robert - 3 
 
 North- West Passage - - 175 
 
 Nutation, of earth's axis - 63 
 
 Odling, W. - - 141 
 
 Ohm - 82, 114 
 
 Ohm's law - 134, 147 
 
 Oncometer, renal - - 306 
 Onnes, Kamerlingh - 140 
 
 Optical instruments - 90, 97, 98, 
 169, 170, 172 
 Optics, physiological - - 299 
 
 (See also under Light.) 
 Orchidese - - - 244, 247 
 Origin of Species - 248, 273 
 
 Reception of - 279, 286 
 " Ornithology," Willughby's 259 
 
 Osmosis, G. 
 Otley, J. - 
 Oughtred, W. - 
 Owen, Sir R. 
 Owens, John 
 Owens College - 
 
 PAGE 
 
 - 145 
 
 - 314 
 
 - 94 
 
 - 265-7 y 317 
 
 - 148 
 
 - 148 
 
 Palladium, discovery of - 145 
 
 Papin, D. - 100, 101 
 
 Parallax, stellar - 61, 90, 168 
 
 Parry, E. - 175 
 
 Parsons, Sir C. - - 187 
 
 Pascal - 76 
 Patents examined by Royal 
 
 Society - - 204 
 
 Paxton, Sir J. - - 245 
 
 Peacock, G. - - 118,119 
 
 Pearson, K. - - 286, 287 
 Pendulum : 
 
 Anchor escapement - 95 
 
 " Gridiron " - 96 
 
 Rater's - 175 
 
 Pennant, Thomas - - 262 
 
 Penny, T. - - 220 
 
 Pentane lamp - 141 
 
 Pepys, S. - - 222, 226 
 
 Perkin, W. - 199-201 
 Petrograd Academy - 209,211 
 
 Petrography - - 164 
 
 Phillips, J. - 315, 316 
 
 " Phlogiston " - 14, 84 
 Photography : 
 
 Astronomical - 168-170 
 
 Colour 173-4 
 
 History - - 166, 172-4 
 Physic Garden : 
 
 Chelsea - - 241 
 
 Dublin - - 254 
 
 Lambeth - - 261 
 
 " Physiologus " - - 216 
 
 Physiology - 294-307 
 
 of plants - 237, 249 
 
 Phy to -geography - - 255 
 
 Phytophthera infestans - 250 
 
 Picard - 10, 11 
 
 Pigot, T. - 50 
 
Index 
 
 331 
 
 PAGE 
 Plants : 
 
 Binomial nomenclature 
 of - - 239 
 
 Classification of, natural 
 system - - 245 
 
 Physiology of - 237, 249 
 Playfair, J. - 70, 131, 310 
 
 Playfair, L. - - 202 
 
 Pliny - 216, 217, 257 
 
 " Poikilitic " - - 316 
 
 Poisson - - 20 
 
 Polarization of heat - - 133 
 Polarization of light - 19, 147 
 Pond, J. - - 60 
 
 Potassium, discovery of - 113 
 Potential - - - - 123 
 Poynting, John 152, 160, 161 
 
 Powell, J. Baden 121, 140, 141 
 Prestwich, Sir J. - 317, 319 
 Prevost - - 156 
 
 Priestley, J. - - 14, 84, 238 
 Pringle, Sir J. - - 204 
 
 Pritchard, C., astronomical 
 
 research - 141 
 
 Pritchard, M. - - 274 
 
 " Principia " - 10 
 
 Professorships : 
 
 Dates of foundation - 46 
 Proteaceae - 244 
 
 Prout, W. - 181 
 
 Pullen, Capt. - - 291 
 
 Pump, air - - 75, 181 
 
 Turbine - - 151 
 
 Pythagoras 8 
 
 Quaternions 
 
 137 
 
 Radiation of heat, see under 
 
 Heat. 
 
 Radio-activity - - 183 
 
 Radiometer - 151, 180, 181 
 Radium, discovery of 183, 184 
 Rainbow, explanation - 120 
 
 PAGE 
 
 Ramsay, Sir W. - 181 
 
 Ramsden, J. - 81, 97 
 
 " Ramsden's eyepiece " - 97 
 Rankine, W. J. M. - - 134 
 Ray, J. - 231, 233, 259, 261 
 Rayleigh, Lord - 122, 159, 164 
 Discovery of argon - 181 
 First step in colour photo- 
 graphy - - 173 
 Refraction, see under Light. 
 Renal oncometer - - 306 
 Respiration ' "V''. - 296 
 Reinold, A. - - - 160 
 Reynolds, O. - 23, 26, 150 
 Rhodes, Cecil - - 168 
 Rhodium, discovery of 145 
 Rickets - - 297 
 Roberts, I. - ^ - 170 
 Robison, J. - - 65, 68, 81 
 Rocks, arrangement in layers 309 
 Roebuck, J. - - 194 
 Roemer, O. 62 
 Roentgen, W. C. - 183 
 Romanes, G. J. - - 285 
 Ronalds, SirF. - 187, 188, 209 
 Roscoe, H. E. - - 149, 150 
 Ross, Sir James - 288, 289 
 Ross, Sir John - - 289 
 Rosse, Lord - - 169 
 Routh, E. J. - - 127 
 Roy,Maj.-Gen. - - - 207 
 Roy, C. S. - 306 
 Royal Astronomical Society 
 
 208, 212 
 Royal College of Chemistry 
 
 194, 199 
 
 Royal College of Physicians 265, 
 294, 295 
 
 Royal College of Surgeons 265, 283 
 Royal Institution, founda- 
 tion - - 109, 213-4 
 Royal Society - 51,77,203-213 
 Royal Society of Arts - 211 
 Royal Society of Dublin - 211 
 Royal Society of Edinburgh 211 
 Rubber, commercial produc- 
 tion of - - 190 
 Rucker, A. - 160 
 Rumford, Count 27, 107, 108, 213 
 
332 
 
 Index 
 
 PAGE 
 
 Russian Academy communi- 
 cations to Royal Society - 
 
 209, 211 
 
 Rutherford, D. - 68 
 
 Rutherford, Sir E. - - 183 
 
 Sabine, Gen. Sir E. 175, 207, 209 
 Safety lamp - - 116 
 
 Safety valve, invention of - 101 
 Salter, J. W. - 313, 314, 317 
 Salmon, G. - 137 
 
 Salvin, O. - 293 
 
 Sanderson, Sir B. - - 304 
 Sandstone : 
 
 Red, new - '* ' - 316 
 Old - - 315 
 
 Sap, ascent of - - 232,238 
 Saron - - 91 
 
 Saturn's rings - - 128 
 
 Savery, Thomas - 100, 104 
 Scheele - - 172 
 
 Schehallien experiment 64, 86, 87 
 Scottish universities, scienti- 
 fic activity - ., 64, 130 
 Schunck, Edward - - 163 
 Sea, exploration of - " - 288 
 Sedgwick, A., sen. 271, 310, 314 
 Sedgwick, A., jun. - - 285 
 "Seiches" - 134 
 
 Seismology Wg 133, 178, 214 
 Semaphore - 188 
 
 Sextant, invention of - - 95 
 Sexuality of plants . - 235, 236 
 Sharpey, W. - - 304 
 
 Sherard, W. - - - 251 
 Shore, L. - - 303 
 
 Sibthorp, J. J. - * 251 
 
 Siemens, W. - '0% - 192 
 Silurian rocks - - 314 
 
 Simpson, Thomas 56 
 
 Simpson, Sir J. Y. - 305 
 
 Slide rule, invention of - 94 
 Sloane, Sir H. - - 240 
 
 Smith, Adam - 65, 68 
 
 Smith, H. J. - 140-3 
 
 Smith, Sir J. E. - 232, 240 
 
 Smith, L. - 306 
 
 PAGE 
 
 Smith, Robert - 71, 90 
 
 Smith, R. A. - 149 
 
 Smith, W. - - 309, 318 
 
 Snell - - 53 
 
 Sodium, discovery of - - 114 
 Soddy, F. - 183 
 
 Solander, D. - - 241, 242 
 Solar system, motion in 
 
 space - - 93 
 
 Sorby, H. C. - - 163, 312 
 Sound - - 50, 71, 77 
 
 Sowerby, J. de C. - - 317 
 Solvay, E. - 194, 198 
 
 Spottiswoode, W. - - 163 
 Spectroscopy - - 153-159 
 Applied to Astronomy - 
 
 171-172 
 
 Spirit level - 56 
 
 Stanhope, Lord - 212 
 
 Star catalogue - - 57, 162 
 Star-drifts - 93 
 
 Stars, double - -88, 92 
 
 Steel, scientific production - 187 
 Steam engine : 
 
 Invention of - 99-105 
 Propulsion of ships - 101 
 Turbine - - 187 
 
 Stewart, Balfour 150, 152, 209 
 Theory of exchanges - 158 
 Stewart, M. - - 56 
 
 Stereoscope, invention of - 148 
 Stokes, G. G. - 20, 32, 123-5 
 Radiation and absorp- 
 tion - 157, 158 
 Stoney, G. J. - - 139, 182 
 Strontium, discovery of 130 
 Sturgeon, W. - 24, 148, 191 
 Survey - - 174, 207 
 Sutherland, J. - - 253 
 Swan,W. - - 154 
 Sydenham, T. - - 296 
 " Sylva " - - 225 
 Sylvester, J. J. - - 128, 141 
 Symmer, R. - 79 
 
 Tait, P. G. 
 Talbot, F. 
 Taylor, B. 
 
 127, 133, 139 
 - 153, 173 
 
 - 77 
 
Index 
 
 333 
 
 PAGE 
 
 Tawney, E. B. - - 313 
 
 Teall, J. J. H. - - 311 
 
 Telegraphy : 
 
 Invention of - 187 
 
 Submarine- - 189 
 
 Wireless - - 33 
 
 Telescope, reflecting 52, 54, 169, 
 
 170 
 
 Refracting- 54, 172 
 
 Temperature, critical - 140 
 
 Tennant, C. - - 195 
 
 Terrestrial magnetism, see 
 
 under Magnetism. 
 Thales - 8 
 
 Thallium - - - 159 
 
 " Theater of Insects " - 220 
 Theobaldus - - 217 
 
 Thermodynamics : 
 
 First law - - 23 
 
 Second law of - 26, 28 
 Thermometer - - 83 
 
 Self-registering - - 288 
 Thin films, thickness mea- 
 sured - - 160 
 Thiselton-Dyer, Sir W. - 249, 
 250, 272 
 Thompson, B., see Rumford, 
 
 Count. 
 
 Thompson, -Vaughan - - 292 
 Thomson, James - 135, 136 
 Thomson, Sir Joseph - 152, 182 
 Thomson,William, see Kelvin, 
 
 Lord. 
 
 Thomson, Wyville - 289, 291 
 Thorpe, Sir E. - - 109, 160 
 Threlkeld, Caleb - - 254 
 Tides - 177, 178 
 
 Time signals - - - 166 
 Topsell, E. - 220, 257 
 
 Torpedo - - 83 
 
 Torsion balance, invention 
 
 of 86, 87 
 
 Townley, R. - - 75, 95 
 Tradescant, John, the elder 260 
 Tradescant, John, the younger 261 
 Transit of Venus, see under 
 
 Venus. 
 
 Transpiration of gases - 145 
 Trevithick, R. - - 104, 105 
 
 PAGE 
 
 Trinity College, Dublin 137-139 
 
 Turbine : 
 
 Engine - - 187 
 
 Pumps - - - 151 
 
 Turner, W. : 
 
 Botany - - 229, 230 
 Zoology ... 256 
 
 Tyndall, J. - 88, 213 
 
 Type printing machine - 191 
 
 Ultra-violet rays - 124 
 
 Uniformitarian theory - 311 
 University College, founda- 
 tion of - - 143-146 
 Uranus, discovery of - - 91 
 
 Vaccines, first used - - 306 
 Vacuum tubes, invention of 162 
 " Valency " - 148 
 
 Vanadium - 150 
 
 Venus, transit of - 52, 63, 88, 
 167, 207, 209 
 
 Vernier - - 56 
 
 Vertebrate, origin of, re- 
 search - - 303 
 Vesalius - - - 219 
 Vines, S. H. - - 250 
 Viscosity of gases - - 34 
 Vives - - 218, 221 
 Volta, A. - - 80, 106 
 Voltaic arc - 114 
 Vulcanite, invention of 190 
 Vulcanization - - 190 
 
 Wallace, A. R. 
 Wallich, Dr. 
 Wallis, John 
 Waltire - 
 Ward, Joshua 
 Ward, M. - 
 
 273, 281 
 291, 292 
 
 - 50 
 
 - 85 
 
 - 194 
 250, 253 
 
334 
 
 Index 
 
 PAGE 
 
 Water: 
 
 Composition of - 85 
 
 Compressibility of - 80 
 Electrolytic decomposi- 
 tion of - - 107 
 Maximum density of - 130 
 Waterston, J. - - 164 
 Watson, W. - - 81 
 Watt, J. - - 69, 70, 101-104 
 Composition of water - 85 
 Wedgwood, T. - - 172 
 Weights and measures, stan- 
 dards - -49,130,207,208 
 " Weismannism " - - 280 
 Weldon, Walter - 198 
 Weldon, W. R. F. - 277, 286 
 Wells, W. C. - - 176 
 Wernerian theory of geology 
 
 310, 311 
 
 Westbrook, W. - - 306 
 
 Wheatstone, Sir C. - 147, 148 
 
 Stereoscope invented 
 Spectrum analysis 
 Telegraphy - 
 
 " Wheatstone bridge " 
 
 Wheler, G. 
 
 Whewell, W. - 
 
 Wilcke, J. K. - 
 
 Wilde, Dr. Henry 
 
 Williams, Dr. - 
 
 Williamson, A. M. 
 
 Williamson, W. C. 
 
 Willis, T. - 
 
 Willughby, F. - 
 
 148 
 154 
 188 
 147 
 78 
 119, 223, 271 
 
 59, 192 
 
 - 314 
 
 - 146 
 - 305, 316 
 
 - 297 
 232, 259, 261 
 
 PAGE 
 
 Wilson, A. - - - 176 
 
 Witham - - 316 
 
 Wollaston, F. J. H. - - 86 
 Wollaston, W. H. : 
 
 Chemical discoveries - 145 
 
 Spectrum analysis 153, 155 
 
 Photography - - 172 
 
 Woodhouse, R. - 117 
 
 Wooldridge - - 305 
 
 Woolf, A. - 105 
 
 Worcester, Marquis of, Edw. 
 
 Somerset - - 99, 100 
 
 Wortley, Col. Stuart - - 173 
 
 Wotton, E. - - 220, 257 
 
 Wren, Sir C. - - 51, 297 
 
 Wright, Edward - - 48 
 
 Wright, E. P. - - - 316 
 
 Xenon, discovery of - - 181 
 
 X-ray, discovery of - - 183 
 
 See also Radio-activity. 
 
 Young, T. - 18, 37, 119, 153, 213 
 Brougham's criticism of 20 
 Explanation of super- 
 numerary rainbows - 120 
 Physiological optics 128, 299 
 
 Zoology - 
 
 256-293 
 
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