•Sj'riieriryE.RosGoe CORNELL UNIVERSITY LIBRARY BOUGHT WITH THE INCOME OF THE SAGE ENDOWMENT FUND GIVEN IN 1 8^1 BY HENRY WILLIAMS SAGE /^'chael Faraday; his life and work. 3 1924 012 323 014 Cornell University Library The original of this book is in the Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924012323014 THE CENTURY SCII'JNCE SICRIES Edited BY SIR HENRY E. ROSCOE, D.C.L., LL D.. F.R.8. MICHAEL FARADAY HIS LIFE AND WORK The Century Science Series. Edited hy Sir HENRY ROSCOE, D.C.L., F.R.S. y?.. 6cl. each. Pasteur. Hv Prrcy FRANk-|,A\-D, Ph. D.( W ii rzburg) , r..Sc.(T.ond. ), !■■. 1\.S,, :iiid Mrs. Pkncv FkanivI.and. Humphry Davy, Poet and Philosopher. IJy \. E. Thokif, i.L.l)., F.R.S. Charles Darwin and the Theory of Natural Selection. Ily ttiWAKii B. PoitLTON', M.A., F.R.S. John Dalton and the Rise of Modem Chemistry. lly Sir HexKV R. Ri iscok, V R. S. Major Rennell, F.R.S., and the Rise of English Geography. F>y Sir Ci.emknts R. Markham, C B., F.R.S. Justus von Liebig : his Life and Work (1803-1873). Bv W. A. Shi:nst'im.:, F.FC, Lei:tiirer on Chemistry in Clirti>n College. The Herschels and Modern Astronomy. Bj AciNES RI. Cl.KK'KI^. Charles Lyell and Modem Geology. By Professor T. G. Bonnev, F.R.S. J. Clerk Maxwell and Modern Physics. i)y K. T. Glazkuroi^ic, F.R.S. Michael Faraday : his Life and Work. By Prof. Sii-\-ANus P. Thomi'son, F.R.S. 5s. CASSELL .*v COMPANY, Limited, London, Paris, Nciu \'ork &^ Melbonriie. THE CENTURY SUIENUE SERIEH MICHAEL FARADAY HIS LIFE AND WORK IIY SILVANUS i\ THOMPSON, D.Sc, F.E.S. I'lUM'lI'AL OF AND PROl'K.SS. H; uV PltYSiry, [-_: TlLi: ClTV AND GULLLS 01' LO.NDOX Tei.'UNH.'AL C'0LLE(.;E, r'iNSDI.'l;V CvVSSELL AXD COMPANY, Limited LOiVnON, PARIS, XRW YORK ,y- MRLBOURNE 18! IS [all riohts rf.sf.rved] ON A ruliTKAlT OF FARADAY. AVas ever man so ainijjle and so sage, So crowned and yet no careleys of a prize ! Groat Faraday, who made the wurld so wise, And loved the lahouv better than the wage. And this j'ou say is how ho looked in age, AVith that strong Lrow and these groat humLlo eyes That seem to look with reverent surprise On all outside himself. Turn o'er the page, Recording Angel, it is white as snow. Ah God, a fitting messenger was he To show Thy mysteries to us below. Ohild as he came has he returned to Thee. Would he could come but once again to show The wonder-deep of his siinpiicity. Cosmo AIoxkhouse. PREFACE Sm.'RTLY after the deatli of Farada}' in 1^G7. three biograjjhit'S of hiiu—eaeh admirable in its own Hne — were piildished. Tlie " Life and Letters of Faraday/' by 1 'r. Eence Jones, secrt-tar}" ot the Er-yal Institiui' exist : the "■ Floge Historique " of M. Dumas: the article •■ Faraday '" in the ■" Fncyclopa:-dia Britannica "' by Professor (.lerk !^Lxxwell : and the chapter on Faraday in 1 'r. W. Garnett's '■ Heroes of Science." But there seenis r'jom t'nY another account of the life and lab'.'urs of the man whose influence upon tlie century in wliich Vlll MICHAEL FARADAY. ho lived was so great. For forty years lie was a livint;- and inspiring voice in the PLoyal Institution, beyond all question the greatest scientific expositor of his time. Throughout almost the whole ot that time his original researches in physics, and chicHy in electricitv, were extending the boundaries of knoAv- ledge and laying the foundations not *»nly for the great developments of electrical engineering of the last twenty years but for those still greater develop- ments in the theories of electricity, magnetism, and light which are every year being extended and made fruitful. Were there no other reason than these developments in practice and theory, they would amply justify the effort to review now, after so many years, the position of Faraday amongst the eminent men of the century now drawing to its close. Those who were intimately acquainted with him are a fast dwindling band. In the recollection of such as have survived him, his image lives and moves, surrounded with gracious memories, a vivid personality instinct with rare and unseltish kindliness. But the survivors are few, and their ranks orosy thinner with each succeeding year. And so it comes about that the task of writing of his life and worlv has been entrusted to one who never ceases to re^q-ct that he never met Faraday. PREFACE. IX Thanks tu tlio pennissioii of the managers of the Koyal Institution, a number of short extracts from Fara(Ia3^'s notebooks, hitherto unpubhshed, are now printed for the first time. Mucli more remains which it is to l.)C hoped, for the benefit of science, may be published ere long. The author desires further to acknowledo^e the kindness of Messrs. Loni-^mans & Co. in allowing the reproduction of the illustrations on pages o and 258, whicli are taken from Bence Jones's "Life and Letters of Faraday," published in ISOS. Mr. Elkin Mathews has kindly permitted the inser- tion of the sonnet by Mr. Cosmo Monkhouse which follows the title-page. The author is also indebted to Dr. J. Hall Gladstone, F.R.S., for many valualjle notes and suggestions, and to Miss M. K. Reynolds for photographs used in preparing Fig. 14. Most of all he is indebted to Miss Jane Barnard for access to Faraday's private papers, and for permission to print certain extracts from them. S, R T. CONTENTS PAGE Chap. T. — Evht,v Life. Tkaixino. and Travel ... 1 Chap. II. — Life at the Koyai. Ixstitution . . , .00 Chat. III. — ISciextific Keseaucties — First Pekiuu . To Chap. IA^. — Scientific Keseakche.s — Secund Pehiud . 1U2 Chap. A". — Si/ientific ^iE^EARcnEs — Thihd Peiuoj) . . 172 Chap. VI. — AIiddle and Later Life ..... 'J22 Chap. A'IL— A'iews ox the Pii;suit of Sltlxce axd ox Educatiox ....... 2G1 Chap. A'III. — Keligiuvp A^iEWb ...... 2SG LIST OF ILLUSTRATIONS Portrait FIGS. 1 Riebau's Shop ....... 2. Electronifignetic Uutatioii-s (facsimile sketch 3. Apparatus for Rotation (facsimile skoti-h) 4. Faraday's Ring {facsimile sketch) 5. Induction Experiment {facsimile sk-etch) G. The '^ Xow Electrical Machine " (facsimile sketch) 7. The Teetotum Apparatus ..... IS. The Revolving- Copper Cylinder (facsimile sketch) 9. Earth Inductor ....... 10, A Spark from a Magnet (t';icsimile sketch) 11. Ildw to Cut the IMagnetio Lines Illustration of the New Ti'rms (facsimile sketch) Bundle of AVires (facsimile sketch) A})p;u-atus for Investigating Dielectric Cup.icity Block of Heavy-glass (facsimile sketch) IG. Action of Miignet on Light (facsimile sketch) IT. AtTimgemi.'nts of Miignuts (facsimile sketch) 18. The Ring Electromagnet (facsimile sk.etch) 19. The Equatorial Position .... 20. Illustratiun of Lateral Vibrations 21. A Lecture Model . , , . . 22. Cottage at Hampton Court PAGE 3 88 88 108 111 121 123 124 12o 129 133 145 l.')! 159 17G 177 178 179 188 195 239 258 MICHAEL FARADAY. CHAPTER I. EARLY LIFE, TRAINING, AND TRAVEL. On the 22nd of September, 1791, was born, at Newington Butts, then an outlying Surrey village, but since long surrounded and swallowed up within the area of Greater London, the boy Michael Faraday. He was the third child of his parents, James and Margaret Faraday, who had but recently migrated to London from the little Yorkshire village of Clapham. Clapham lies under the shadow of Ingle- borough, on the western border of the county, midway between Settle and Kirkby Lonsdale. The father, James Faraday, was a working blacksmith ; the mother, daughter of a farmer of Mallerstang, the romantic valley which runs past Pendragon Castle to Kirkby Stephen. James Faraday Avas one of the ten children of a Robert Faraday, who in 1756 had married EHzabeth Dean, the owner of a small home- stead known as Claphum Wood Hall, since pulled down. All Robert Faraday's sons appear to have been brought up to trades, one being a -shoemaker, R 2 MICHAEL FARADAY. another a q-rocer, another a farmer, another a nax- workcr, and another a shopkeeper. Descendants ot some of these still hve in the district. After Michael's birth, his parents moved to the north side of the Thames, living for a short time in Gilbert Street, but removing in 179G to rooms over a coach-house in Jacob's Well Mews, Charles Street, ]\Ianchester Square, Avhere the}^ lived till 1809. In that year, young Michael being now nearly eighteen years old, they moved to IS, Weymouth Street, Portland Place. Here in the succeeding year James Faraday, who had long been an in- valid, died ; his widow, who for some years re- mamed on at Weymouth Street, maintaining herself by taking in lodgers until her sons could support themselves and her, survived till 1838. Though a capable woman and a good mother, she was quite uneducated. In her declining years she was wholly supported by her son, of whom she was very proud, and to whom she was devoted. Michael received very little schooling. One of his nephews tells the following tale of his boy- hood. He was at a dame's school ; and, either from some defect in his speech or because he was too young to articulate his r's properly, he pronounced his eider brother's name " Wobert." The harsh schoolmistress, bent on curing the defect by personal chastisement, sent the aforesaid " Wobert " out with a halfpenny to get a cane, that young Michael might be dul}^ flogged. But this refinement of cruelty reacted on itself; for Robert, boiling with indignation, pitched the halfpenny over a wall, and went home to tell his BOOKP.INDEirs EKRAND-BOV. 3 mother, who promptly came down to the scene of action and removed both boys from the school. From the age of five to thirteen Michael lived at Jacob's Well Mews, spending his out-of-school hours ll Jil iA ,llllll I'li; 'iiill 'i h 1 M i I U II ^ —^ 1 ' 1 i| "1 KIEJiAU S SHUP. at home or in the streets playing at marbles and other games with the children of the neighbourhood. In 1804 he went on trial for twelve months as errand-boy to a bookseller and stationer at No. 2, Blandford Street — Mr. George Riebau. This house, which is still kept as a stationer's shop (by Mr. William Pike), is now marked with an enamelled . tablet recording its connection with the 4 MICHAEL FARADAY. life of Faraday.-^ When he first went to Mr. Riebaii, it was his duty to carry round the newspapers in the morning. He has been graphically described as a bright-eyed errand-boy who " slid along the London pavements, with a load of brown curls upon his head and a packet of newspapers under his arm." Some of the journals were lent out, and had to be called for again. He Avas very particular on Sunday mornings to take them round early, that he might complete his work in time to go with his parents to their place of Avorship. They belonged — as his grandfather before him — to the sect known as Sande- o manians, a small body Avhich separated from the Presbyterian Church of Scotland towards the middle of the eighteenth century. Their views, which were very primitive, were held Avith intense earnestness and sincerity of purpose. Their founder had taught that Christianity never was or could be the formal or established religion of any nation Avithout subvertmg its essential principles ; that religion Avas the affair of the individual soul; and that "the Bible" alone, Avith nothing added to it or taken aAvay from it by man, Avas the sole and sufficient guide for the soul. They rejected all priests or paid mmisters, but recognised an institution of unpaid eldership. Their Avorship Avas exceedingly simple. Though their numbers Avere fcAV, they Avere exceedingly devout, simple, and exclusive in their faith. Doubtless the rigorous moral influences pervading the family and ^' Faraday's usual place of work at bookbinding was a little room on the left of the entrance. [See the story of his visit there with Tyndall in after years, as narrated in Tyndall'a " Faraday," p. 8.) APPRENTICED AS BOOKBINDER. 5 friends of James Faraday had a great part in moulding the character of young Michael. To his dying day he remained a member of this obscure sect. As he was no merely nominal adherent, but an exceedingly devoted member, and at two different periods of his life an elder and a preacher, no review of his life-work woidd be complete with- out a fuller reference to the religious side of his character. After the year of trial, Michael Faraday was formally apprenticed to learn the arts of bookbinder, stationer, " and bookseller," to Mr. Riebau. The in- denture* is dated October 7, 1805. It is stated that, " in consideration of his faithful service, no premium is given." During his seven years of apprenticeship there came unexpected opportunities for self-improve- ment. Faraday's lifelong friend and co-religionist, Cornelius A'^arley, says : — " When my attention was first drawn to Faraday, I was told that he had been apprenticed to a bookbinder. I said he was the best bookworm for eating his way to the inside ; for hundreds had worked at books only as so much printed paper. Faraday saw a mine of knowledge, and resolved to explore it." To one of his friends he said that a book by Watts, '■' On the Mind," first made him think, and that the article on " Electricity " in a cyclopaedia which came into his hands to be bound first turned his attention to science. He himself wrote : — '' Whilst an apprentice I loved to read the scientific books which were under my hand ; and, ^ Still preserved in Faraday's Diploma-book, now in the possession of the Royal Society. 6 MICHAEL FARADAY. amoncrst them, delis-^btecl iii Marcet's 'Conversations in Chemistry' and the electrical treatises in the ' Encyclopaedia Britannica.' I made such simple experiments in chemistry as could he detrayed m their expense by a fe^v pence per Aveek. and also constructed an electrical machine, tirst ^vith a c^lass pliial, and afterwards with a real cylinder, as well a.s other electrical app>aratus of a corresponding kind." This early machine * is now preserved at the Eoyal Institution, to -which it was presented Ly Sir .Tames South. Amono-st the books which he had ti) bind were Lvons' "Experiments on Electricity" and Boyle's " Notes about the Producibleness of Chymicall Principles/' which books, together with Miss pjurnev's " Evelina," all boimd with his own hands, are still preserved in the Roval Insti- tution. AValking ]iear Eleet Street, he saw displayed a bill announcing that evening lectures on natural phil- osophy were delivered by Mr. Tatum at 53, Dorset Street, Salisbury Square, E.C., price of admission one shilling. With his master's permission, and monev furnished by his elder brother Robert, who was a blacksmith and (later) a gastitter, Michael bec^an to taste scientitic teaching. Between Eebruarv, ISIO, and September, IMl, he attended some twelve or thirteen lectures. He made full and beautiful notes of all he heard : his notebooks, bound bv him- self, being still preserved. At these lectures he fell in with several thoroughly congenial comrades, one An account of this machine will be found in the Argonaut vul. ii., p. 33. NEW ACQUAIXTAXCES. / of theiH, by name Uenjamin Abbott, being a well- edncated young Quaker, who was contidential clerk in a mercantile house in the City. Of the others — amongst whom were IMagrath, Newton, Nicol, Hux- table, and Richard PhiUips (afterwards F.R.S. and President of the Chemical Society) — several remained lifelong friends. Happily for posterit}^ the letters — long and chatty — Avhich the lad wrote in the fulness of his heart to Abbott have been preserved ; they are published in IJence Jones's "Life and Letters." They are remarkable not only for their vivacity and freshness but for their elevated tone and ex- cellent composition — true specimens of the lost art of letter-writing. The most wonderful thing about them is that they should have been Avritten by a bookbinder's ajiprenticc of no education beyond the common school of the district. In his very lirst letter he complains that ideas and notions which spring u]) in his mind "are irrevocably lost for w^ant of noting at the time." This seems the first premoni- tittn of that loss of memory wdiich so afflicted him in after life. Tn his later years he always carried in his waistcoat pocket a card on which to jot down notes and memoranda. He would stop to set down his notes in the street, in the theatre, or in the laboratory. Riebau, his master in the bookbinding business, seems, from the way he encouraged the studies of his young apprentice, to have been no ordinary man. His name would suggest a foreign extraction ; and to his shop resorted more than one political refugee. There lodged at one time at Riebau's an artist named S MICHAEL FARADAY. Masquerier,* who had painted Xapoleous portrait and had tied from France during the troublous times. For the apprentice boy, who used to dust his room and black his boots, Masquerier took a strong liking. He lent him books on perspective and taught him hou' to draw. Another frequenter of Riebau's shop was a Mr. Dance, whose interest in the industry and in- telligence of the apprentice led him to an act which changed the Avhole destiny of his life. Faraday himself, in the very few autobiographical notes which he penned, wrote thus : — During my apprenticeship I had the good fortune, through the kindness of Mr. Dance, who was a customer of my master's shop and also a member of the Eoyal Institution, to hear four of the last lectures of Sir H. Davy in that locality.t The dates of these lectures were February 29, March 14, April 8 and 10, 1S12. Of these I made notes, and then wrote out the lectures in a fuller form, interspersing them with such draw- ings as 1 could make. The desire to be engaged in scientific occupation, even though of the lowest kind, induced me, whilst an apprentice, to write, in my ignorance of the world and simplicity of my mind, to Sir Joseph Banks, then President of the Royal Society. Naturally enough, " Xo answer" was the reply left with the porter. He submitted his notes to the criticism of his friend Abbott, with whom he discussed chemical and electrical problems, and the experiments which they had individually tried. Out of this; correspondence, "■ " When he [Famday] was young, poor, and altogether unkno\^-n ilasquerier was kind to him; and now that he is a great man he does not forget his old friend." — Diary of H. C'rahh Eobinson, vol. iii p. 375. t He alwavs sat in the o-allerv over the clock. LET'I'ERS TO ABliOTT. \) one letter only can be given ; it Avas written Sep- tember 28, 1812, ten days before the expiry of his apprenticeship : — Dear A , . . . T will hurry on to philosophy, where I am a little more sure of my grouod. Your card was to me a very interesting' and pleasing ol'ject. I was highly gratified in observing so plainly delineated the course of the electric fluid or fluids (I do not know which). It appears to me that by making use of a card thus prepared, you have hit upon a happy illustrating medium between a conductor and a non-conductor ; had the interposed medium been a conductor, the electricity would have passed in connection through it — it would not have been divided ; had the medium been a non-conductor, it would have passed in connection, and undivided, as a spark over it, but by this varying and disjoined conductor it has been divided most efi"ectually. iShould you pursue this point at any time still further, it will be necessary to ascertain by what particular power or eflbrt the spark is divided, whether by its aflinity to the conductor or by its own repulsion ; or if, as I have no doubt is the case, by the joint action of these two forces, it would be well to observe and ascertain the proportion of each in the effect. There are problems, the solution of which will be diflicult to obtain, but the science of electricity will not he complete without them ; and a philosopher will aim at perfec- tion, though he may not hit it— difficulties will not retard him, but only cause a proportionate exertion of his mental faculties. I had a very pleasing view of the planet Saturn last week through a refractor with a power of ninety. I saw his ring very distinctly ; 'tis a singular appendage to a planet, to a revolving globe, and I should think caused some peculiar phenomena to the planet within it. I allude to their mutual action with respect to meteorology and perhaps electricity. . . . The master, a French emigre named De la Roche, of King Street, Portman Square, to whom he en- gaged himself as a journeyman bookbinder, was of a 10 MiCtlAEL FARADAY. very passionate disposition, and made Faraday very luiconifortable. He long-ed to tret out of trade, and under the enconragenient of Mr. Dance he wrote to Sir Humphry Davy, sendino", " as a proof of my earnestness,*' the notes he had taken of Davy's h\st four lectures. Faraday's letter, which has been preserved but never publislied, is an astounding example of the high-tlown cringing style in vogue at that date. Davy's reply was favourable, and led to a temporary engagement of some days as amanuensis at the time when he was Avounded in the eye by an explosion of the chloride of nitrogen. Faraday him- self, nearly twent}' 3^ears afterwards, wrote* a full account of the circumstances. [J/. Faroda^/ to Dr. J. A. ParU] Royal Institution, December i2;5, 18:^0. ^[Y itEAE 8ut,— You asked iiie to give you an account of ruy tiri^t introduction to Sir H. Davj^ whicli I inn very hapjiy to do, as I tliink the circumstances will hear testimony to his goodness of heart. When [ was a bookseller's apprentice, I was very fond of experiment and very adverse to trade. It happened that a gentleman, a member of the hoyal Institution, took nie to hear some of Sir H. Davy's last 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 seltish, 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. Davv» expressing my wishes, and a hope that, if an opportunity cnnie ^■- See Dr. Paris's "Life of Davy," vol. ii., p. 2 ; or Bcnce -Toiify's ■ Life and Letters of Faraday," vol. i., p. 47, WINS FAVOUR WITPI DAVY. 11 in his way, he would favour my views ; at the same time, I sent the notes I had taken of his lectures. The answer, which makes all the point of my communica- tion, I send you in the original, requesting you to take great care of it, and to let me have it back, f.n- you may imagine how much I value it. Vou will observe that this took iilace at the end of the year 1812, and early in ]SI3 he requested to see me, and tohl me of the situation of assistant in the laboratory of the luiyal Institution, then just 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 Avas a harsh mistress ; and in a pecuniary point of view but ])Oorly reward- ing those who devoted themselves to her service. He smiled at my notion of the superior moral feelings of philosophic men, and said he Avoukl 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 lioyal 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 in writing. I returned Avith him in April, 1815, resumed my station in the lioyal Institution, and have, as you know, ever since remained there. I am, dear Sir, very truly yours, M. Faraday. The following is Davy's note : — Mr. P, FfAi-adaij, 183, Weymouth St., Portland Place. December 24, 1812. Sir, — I am far from displeased with the proof you have given me of your confidence, and which displays great zeal, power of memory, and attention. I am obliged to go out of Town, and shall not be settled in town till the end of Jan^' 12 MICHAEL FARADAY. I will then see you at any time you wish. It would gratify me to be of any service to you ; I wish it may be in my power. I am Sir your obt. humble servt. H. Davy. Accordingly, Faraday called on Davy, who received him in the anteroom to the lecture theatre., hy the window nearest to the corridor. He advised him then to stick to bookbinding^, promising to send him books from the Institution to bind, as well as other books. He must have been agreeably impressed, otherwise he would not, when disabled, have sent for Faraday to write for him. Early in 1813 the humble household, in which Faraday lived with his widowed mother in "Weymouth Street, was one night startled by the apparition of Sir Humphry Davy's grand coach, from which a footman alighted and knocked loudly at the door. For young Faraday, who was at that moment undressing upstairs, he left a note from Sir Humpbry Davy requesting bun to call next mornino-. At that interview Davy asked him whether he was still desirous of changing his occupation, and offered him the post of assistant in the laboratory' in place of one who had been dismissed. The salary was to be twenty-live shillings a week, Avith two rooms at the top of the house. The minute appointing him is dated March 1, 1813: — Sir Humphry Davy has the honour to inform the managers that he has found a person who is desirous to occupy the situation in the Institution lately filled by William Payne. His name is Michael Faraday. He is a youth of twenty-two years of age. As far as Sir H. Davy has been able to observe ENTERS ROYAL INSTITUTION. 18 or ascertain, he appears well fitted for the situation. His habits seem good, his disposition active and cheerful, and his manner intelligent. He is willing to engage himself on the same terms as those given to Mr. Payne at the time of quitting the Institution. Resolved— That Michael Faraday be engaged to fill the situation lately occupied by ^Ir. Payne on the same terms.* There have come down several additions to the story. One, probably apocryphal, says that Faraday's first introduction to Davy was occasioned by Davy's caUing at Riebau s to select some bookbinding, and seeing on the shelves the bound volume of manuscript notes of his own lectures. The other was narrated by Gassiot to Tyndall, as follows : — Clapham Common, Surrey, Xovember 28, 1867. My dear Tyndall, — Sir H. Davy was accustomed to call on the late Mr. Pepys in the Poultry, on his way to the London Institution, of which Pepys was one of the original managers ; the latter told me that on one occasion Sir H. Davy, showing him a letter, said, " Pepys, what am I to do 1 — here is a letter from a young man named Faraday ; he has been attend- ing my lectures, and wants me to give him employment at the Koyal Institution — what can I do "? " " Do 1 " replied Pepys, * His duties as laid down by the managers were these : — " To attend and assist the lecturers and professors in preparing for, and during lectures. Where any instruments or apparatus may be required, to attend to their careful removal from the model-room and laboratory to the lecture-room, and to clean and replace them after being used. reporting to the managers such accidents as shall require repair, a constant diary being kept by him for that purpose. That in one day in each week he be employed in keeping clean the models in the repository', and that all the instruments In the glass cases be cleaned and dusted at least once within a month." 14 MICHAEL FARADAY. "put him to wash bottles ; if he is good for anything he will do it directly ; if he refuses, he is good for nothing. " " Xo, i^O' replied Davy, "we must try him with something better than that."' The result was, that Davy engaged him to assist m the Laboratory at weekly wages. Davj' held the joint office of Professor of Chemistry and Director of the Laboratory; he ultimately gave up the former to the late Professor Brande, but he insisted that Faraday should be appointed Director of the Laboratory, and, as Paraday told me, this enabled him on subsec^uent occasions to hold a definite position in the Institution, in TS'hich he was always supported by Davy. I believe he held that office to the last. Believe me, my dear Tjmdall, yours truly, J. P. Gas.^iot. In ISOS ]\Ir. latum had founded a City Philo- sophical Society.* It consisted of thirty or forty young men in humble or moderate rank, who met on AVednesdays for mutual instruction ; lectures being given once a fortnight by the menrbers in turn. Tatum introduced Faraday' to this Society in 1813. Edward Magrath was secretary. Amongst Faraday's notes of his life is the followinc^ : — o During this spring Magrath and I established the mutual- improvement plan, and met at my rooms up in the attics of the Pioyal Institution, or at Wood Street at his vrarehouse. It consisted perhaps of half-a-dozen persons, chiefly from the City Philosophical Society, who met of an evening to read together, and to criticise, correct, and improve each other's ^' The City Philosophical Society was given up at the time when Mechanics' Institutes were started in London, Tatum. selhua- his axjparatus to that estahlished in Fleet Street, the forerunner of the Birkheck Institution, !llany of the City Society's members joined the Society of Arts. AT WORK IX CHEMI>TliY. 15 pronunciation and oonstmction of language. The discipline was very sturdy, the remarks very plain and open, and the results most valuable. This continued for several years. He "writes, after a ^-eek of work at tlie R'.>val Institution, to Abbott : — Pioyal Institution. March 8, 1^13. It is now about nine o'clock, and the thought strikes me that the tongues are going both at Tatum's and at the lecture in Bedford Street : but I fancy myself much better employed than I should have been at the lecture at either (.if those places. Indeed, I have heard one lecture already to-day, and had a tiDger in it (I can't say a hand, for I did very little). It was by ;Mr. Powell, on mechanic?, or rather on rotatory motion, and was a pretty good lecture, but not very fully attended. As I know you will feel a pleasure in hearing in what I have been or shall be occupied. I will inform you that I have been employed to-day, in ]iart. in extracting the sugar from a portion of beetroot, and also in making a compound of sulphur and carbon— a combination which has lately occupied in a considerable degree the attention of chemists. With respect to next "Wednesday. I shall be occupied until late in the afternoon by Sir H. Davy, and must therefore decline seeing you at that time ; this I am the more ready to do as I shall enjoy your company next Sunday, and hope to possess it often in a short time. Tlie next letter to Abbott, dated April 9. recounts an explosion in which both he and Sir Humphry Davy received considerable hijury. In June he wrote to Abbott four very remarkable letters concernincr lectures and lecturers. He had already- heard Tatum and Dayy, and had now assisted Brande and Pi;'weU in their lectures, and had keenly observed their habits, peculiarities, and defects, as Avell as the etiects they 16 :^^TCHAEL faraday. produced on the audience. He writes without the slightest suspicion of suggestion that he himself has an}- likehhood of becoming a lecturer, and says that he does not pretend to any of the requisites for such an office. " If I am unfit for it," he sa3's, " 'tis evident that I have yet to learn : and how learn better than by the observation of others ? If we never judge at all. we shall never judge right.'' " L too, have in- ducements in the C[ity] r[hilosophioal] S[ociety] to draw me forward in the acquisition of a small portion of knowledge on this point." *' I shall point out but few beauties or few faults that I have not witnessed in the presence of a numerous assemblv." He begins by considering the proj)er shape of a lecture-room ; its proper ventilation, and need of suitable entrances and exits. Then he goes on to consider suitability of subjects and dignity of subject. In the second of the letters he contrasts the perceptive powers of the eye and ear, and the proper arrano;e- ments for a lecturer's table : then considers diagrams and illustrations. The third letter deals with the delivery and style of the lecture, the manner and attitudes of the lecturer, his methods of keeping alive the attention of the audience, and duration of the discourse. In the fourth of these letters (see p. 228), he dwells on the mistakes and defects of lecturers, their unnecessary apologies, the choice of apt ex- periments, and avoidance of trivialities. In September, 1813, after but six months of work in the laboratory, a proposition came to him from Sir Humphry Davy Avhich resulted in a complete chano-e of scene. It was an episode of foreign travel, lasting PKUFOyALS FOR FOREIGN TRAVEL. 17 as it proved, eighteen months. In the autobio- graphical notes he wrote : — In the autumn Sir H. Davy proposed going abroad, and offered me the opportunity of going with him as his amanuensis, and the promise of resuming my situation in the Institution upon my return to England. Whereupon I accepted the offer, left the Institution on October 13, and, after being with Sir H. Davy in France, Italy, Switzerland, the Tyrol, Geneva, ifec, in that and the following year, returned to England and London April 23, 1815. Before he left England, on Sc].)tcniber 18, 1813, at the request of his mother, he wrote to an uncle and aunt the folloAvino- account of himself: — I was formerly a bookseller and binder, but am noAv turned philosopher, which happened thus : — Whilst an apprentice, I, for amusement, learnt a little of chemistry and otlier parts of philosophy, and felt an eager desire to i)roceed in that way further. After being a journeyman for six months, imder a disagreeable master, I gave up my business, and, by the interest of Sir H. Davy, filled the situation of chemical assistant to the Royal Institution of Great Britain, in which office I now remain, and where I am constantly engaged in observing the works of Nature and tracing the manner in which she directs the arrangement and order of the world. I have lately had proposals made to me by Sir Humphry Davy to accompany him, in his travels through Europe and into Asia, as philo- sophical assistant. If I go at all I expect it will be in October next, about the end, and my absence from home will perhaps be as long as three years. But as yet all is uncertain. I have to repeat that, even though I may go, my path will not pass near any of my relations, or permit me to see those whom I so much long to see. To Faraday, Avho was now twenty-two years old, foreign travel meant much more than to most young c 18 iUCHAEL FARADAY. men of equal age. With his humble bringing up and slender resources, he had never had the chance of seems: the outside "U'orld : he had never, to his own recollection, even seen the sea. "When on Wednesday, October 13, he started out on the journey to Ply- mouth, in order to cross to the port of Morlaix. he began his journal of foreign travel thus: — This niorning formed a new epoch in my life. I have never before, within my recollection, left London at a greater distance than twelve miles. This journal he kept with minute care, with the sole purpose of recalling events to his mind. It gives full details as to Davy's scientific friends and work, inter- mingled with graphic descriptions of scenery : and is remarkable also for its personal reticence. As with many another, so with Faraday, foreii^n travel took in his life the place of residence at a University. In France, in Italy, he received enlarged ideas ; and what he saw of learned men and academies of science exercised no small formative effect upon one then at the most impressionable age. He connnents gaily on the odd incidents of travel : the luminescence of the sea at night : the amazing fuss at the Custom House ; the postilion with his jack-boots, whip, and pouch; the glow-worm (the tirst glow-worm he had ever seen) : and the slim pigs of ^'ormandv At Paris he visits the Louvre, where his chief comment on its treasures is, that by their acquisition Franco has made herself "a nation of thieves." He o'oes to the Prefecture of Pohce for his passport, in which he is described as having " a round chin, a brown beard a large mouth, a great nose/' etc. He visits the A NEW ELE.MENT. 19 churches, Avhere the theatrical air pervading the ph^ce "makes it impossible to attach a serious or important feehnq to what is going on." He comments on the wood tires, the charcoal used in cooking, the washerwomen on the river bank, the internal decora- tions of houses, the printing of the books. Then he goes about with Davy amongst the French chemists. Ampere, Clement, and Desormes come to Davy to show him the new and strange substance " X," lately discovered by M. Courtois. They heat it, and behold it rise in vapour of a beautiful violet colour. Ampere himself, on Xovend^er 23rd, gives Davy a specimen. They carefully note down its characters. Dav}^ and his assistant make many new experiments on it. At hrst its origin is kept a profound secret by the Frenchman. Then it transpires that it is made from ashes of seaweed. They work on it at Chevreul's laborator}^ Faraday borrows a voltaic pile from Chevreul. With that intuition which was character- istic of him, l)avy jumps almost at once to a conclu- sion as to the nature of the new body, which for nearly two years had been in the hands of the French- men awaiting elucidation. When he leaves Paris, they do not wholly bless his rapidity of thought. But Faraday has seen — with placid inditierence — a glimpse of the great Napoleon "sitting in one corner of his carriage, covered and almost hidden by an enormous robe of ermine, and his face overshadowed by a tremendous plume of feathers, that descended from a velvet hat": he has also met Humboldt, and he has heard M. Gay Lussac lecture to about two hundred pupils. 20 MICHAEL FAKADAY. Pumas has recorded in his " Eloge Historiqiie a reflection of the impressions left by the travellers. After speaking of the criticism to T\-hich I^avy "svas exposed during his visit, he says : — His laboratorj' assistant, long before he had ^von his great celebrity by his works, had by his modesty, his amiabiUty, and liis intelligence, gained most devoted friends at Paris, at Geneva, at Montpelher. Amongst these may be named in the front rank ^M. de la Rive, the distinguished chemist, father of the illustrious physicist whom we count amongst our foreign associates. The kindnesses with which he covered my youth contributed not a httle to unite us — Faraday and myself. With pleasure we u^ed to recall that we made one another's acquaintance under the auspices of that affectionate and helpful philosopher whose example so truly witnessed that science does not dry up the heart's blood. At Montpellier, beside the hospitable hearth of Berard, the associate of Chaptal, doyen of our corresponding members, Faraday has left memories equaUy charged with an undjing sympathy which his master could never have inspired. We admired Davy, we loved Faraday. It is December 29 when the travellers leave Paris and cross the forest of Fontainebleau. Faradav thinks he never saw a more beautiful scene than the forest dressed in an aiiy garment of cr3-stalline hoar frost. They pass through Lyons, Montpellier, Ais, Xice, searching on the way for iodine in the sea-plants of the Mediterranean. At the end of January, 1S14, they cross the Col de Tende over the snow at an elevation of 6,000 feet into Ital}-, and And themselves in the midst of the Carnival at Turin. Thev reach Genoa, and go to the house of a chemist to make experiments on the ram torpedo, the electric skate, WITH DAA'Y IN ITALY. 21 trj'ing to ascertain Avhether Avater could be decom- posed by the electrical discharges of these singular Hshes. From Genoa they go by sea to Lei'ici in an open boat, with niuch discomfort and fear of ship- wreck ; and thence by land to Florence. At Florence he goes with Davy to the Accademia del Cimento. He sees the library, the gardens, the museum. Here is Galileo s own telescope — a simple tube of paper and wood, with lenses at each end — with which he discovered Jupiter's satellites. Here is the great burning glass of the Grand Duke of Tuscany. And here is a numerous collection of magnets, includ- ing one enormous loadstone supporting a weight of 150 pounds. They make ''the grand experiment of burning the diamond " in oxygen by the sun's heat concentrated through the Grand Duke's burning glass. They find the diamond to be pure carbon. Then early in April they depart for Rome. From Home Faraday wrote to his mother a long chatty letter summarising his travels, and sending messages of kindly remembrance to his old master Riebau and others. He tells how, in spite of political troubles, Sir Humphry Davy's high name has pro- cured them free admission everywhere, and how they have just heard that Paris has been taken by the Allied troops. At Rome they witness unconvinced some attempts of Morichini to impart magnetism to steel needles by the solar rays. They pass the Colosseum by moon- light, making an early morning start across the Campagna, on the road to Naples, with an armed guard for fear of brigands. Twice, in the middle of 22 MICHAEL FARADAY. ^lay, they ascend A'csuvius, the second time during a partial eruption rendered all the more vivid by the lateness of the hour — half-past seven — at which the edge of the crater was reached. In June they visit Temi, and note tho nearly circular rainbow visible in the spray of the cataract ; and so across the Apennines to Milan, At ]\Ii]an occurs the following entry: — Friday 17th [June, 1814], Milan. Saw M. Volta, who carne to 8ir H. Davy, an hale elderly man, bearing the red ribbon, and very free in conversation. He does ruA record how tbo ceremonious old Count, who had specially attired himself in his Court uni- form to welcor/io the illustrious chemist, Avas horrified at the informal manners and uncourtly dress of tlic tourist philosopher. So, travelling' by Como and Doruo d'Ossola, they come to Geneva, and here remain a long time; and Faraday Avritcs again to his mother and to Abbott. He can even find time to discuss witlj the latter the relative merits of the French and Italian languages, and the trend of civilisation in Paris and in Rome. Twice he sends messages to Riebau. One of his letters to Abbott, in September, contains passages of more than transient interest : — Some doubt.-, have been exj'reftsed to me lately with renpect to the continuance of the iioyal Inntitution ; Mr. Xewrnan can I^robably give a guesH at the i-.-.ue of them. J have three boxe« of books, (fee, there, and I -Jjould be norry if they were lo-.t by the turning uji of unforeseen circum«tanceH ; but f hoj>f; all will hh(\ well ^you will not read thi« out aloud). Remember HINTS OF DTSCOMFORT. 23 me to all friends, if you please. And " now for you and I to ourselves." ... In passing through life, my dear friend, everyone must expect to receive lessons, both in the school of jirosperity and in that of adversity ; and, taken in a general sense, these schools do not only include riches and poverty, but everything that may cause the happiness and pleasure of man, and every feeling that may give him pain. 1 have been in at the door of both these schools ; nor am T so far on the right hand at present that I do not get hurt by the thorns on my left. With respect to myself, I have always ])erccived (when, after a time, I saw things more clearly) that those things which at first appeared as misfortunes or evils ultimately were actually benefits, and productive of much good in the future progress of things. Sometimes I compared them to storms and tempests, which cause a temporary disarrangement to produce permanent good ; sometimes they aftpeared to me like roads — stony, uneven, hilly, and uncomfortable, it is true — but tlie only roads to a good beyond them ; and sometimes I said they were clouds which intervened between me and the sun of prosperity, but which I found were refreshing, reserving to me that tone and vigour of mind which prosperity alone would enervate and ultimately destroy. . . . You talk of travelling, and I own the word is seducing, but travelling does not secure you from uneasy ciicumstances. I by no means intend to deter you from it ; for though I should like to find you at home when I come home, and though I know how much the loss would be felt by our friends, yet I am aware that the fund of knowledge and of entertainment opened would be almost infinite. But I shall set down a few of my own thoughts and feelings, (fcc, in the same circum- stances. In the first place, then, my dear B., I fancy that when I set my foot in England I shall never take it out again ; for I find the prospect so different from what it at first appeared to be, that I am certain, if I could have foreseen the things that have passed, I should never have left London. In the second pl^ce, enticing as travelling is— and I appreciate fully its advantages and pleasures— I have several times been "24 iMU'UAKl, FAKAPAV. iiunv than hulf ilroiaeil to roturn liiustily home: but socoin! thou.i^hts liavo still iiiaiu'i-.l mo to try wlint tlio fniuiv may produce, ami now 1 am only rrtainod 1>>' tlio ^vislt i>l improvo- mont. 1 ha\c loarm'd Just enough to lu-rroivo my i.i;norani'o, ami, asliamod (^f my dofocls in ovi'r> tliin-;, 1 wish to soizo t.lio opportunity of remodyin^^' tbom. The litllo km>wlodi:co 1 hivvo gained in la.ni;nai;vs makes nie wish to know more ol them, and the little I have seen o'i men and manners is jnst enough to make me desirous of seeing more ; added to wdiieli, the glorious opportunity 1 enjoy of iini>ro\ iug in the know^Iodgo ot ehemistry and the seieuees e(tntinually deUMnun(\s nu' to tiuish this voyage with Sir llumithry Davy. Hut if I wisli to enjoy those advantages, 1 liavo to saeriliee uuu'li ; a,ud tliough those saorilices are sueli as an humblo man would not feel, yt^t I cannot (piietty make them. Travelling, toti, 1 find, is almost inconsistent with i-eligittn (1 uieun modern travelling), and 1 am yet so old-fashioned as to remember atnmgly (1 hope perfectly) my youthful education ; and upon tim wholly iiiriHmatic spt^ctrum at IM. Tietet's. They are not yet jierfeeted, but fi'om the use of very delicate air thermometers, it appears tlint the rays i)ro(hu',ing most heat are certainly out of tlio spC:t;trum and la^yond the red ra.ys. Our time has been employed lately in lishing and shooting; and many a (pmil has been killed in the plains n\' ARISTOCRATIC HAUTEUR. 25 Geneva, and many a trout and grayling have been pulled out of the Khone. 1 need not say, dear lien, how perfectly I am yours, M. Faeaday. This letter reveals, what the diary of travel so scrupulously hides, the existence of cu'cuinstances Avhich were hardl}^ tolerable in Faraday's position. To make the reference intelliiiible it should be re- inenibered that Davy, who had come up to London in 1801 as a raw youth, of immense ability but xery uncouth exterior, had developed into a fashionable person, had become the idol of the hour, had married a very wealthy widow, had been knighted, and had given himself up very largely to the pursuits of fashionable society and to the compan}^ of the aristo- cratic hcdii vionde. Lady Davy accompanied Sir Humphr}^ in this Continental tour ; and though Faraday had been taken with them as secretary and scientific assistant, it would seem that he had not always been treated with the respect due to one in that position. The above letter evidently disquieted Abbott, for he wrote back to Faraday to inquire more closely into his personal affairs, telling him he was sure he was not happy, and asking him to share his difficulties. Farada}-, who was now back in Eome, replied in January in a long letter of twelve pages,* '• Two passages may be quoted. "Finally, Sir H. has no valet except myself . . . and 'tis the name more than the thing -which hurts." " ^Vhe^ I return home, I fancy I shall return to my old profession of hoolvseller, for books still continue to please me more than anything else." 26 MICHAEL FARADAV. ■which he says he had mteuded to till with an account of the waterfalls he had seen, but which gives instead a detailed account of his vexations. He had, he said, written his former letter when in a ruffled state of mind. He now gives the explanation. Betore, however, this letter could reach Abbott, the latter had written 3-et more urgently to know what was the matter. To this Faraday replied on February 23rd. As this shorter letter summarises the previous one it may be given here. Both are printed in Bence Jones's ''Life and Letters ": — home, February ^13, 1815. Dear B , — In a letter of above twelve pages I gave ausAvers to your rjue.stion re-^iieetiiig my .situation. It was a subject not wurtb talking about, but I consider your inquiries as so many proofs of your kindness and the interest you take in my vv'elfare, and I thought the most agreeable thanks I could make you would be to answer them. The same letter also contained a short account of a paper written by Sir Humphry Davy on ancient colours, and some other miscel- laneous matters. I am quite ashamed of dwelling so often on my own afFairs, but as I know you wish it, I shall brietiy inform you of my situation. I do not mean to employ much of this sheet of 1 taper on the subject, Ijut refer you to the before-mentioned long letter for clear information. It happened a few daj's before we left Encrlan'l, that Sir Hi's valet declined going vrith him, and in the sliort space of time allowed by circumstances another could not be g(jt. Sir H. told me he was very sorrv but that, if I would do such things as "were absolutely' necessary for him until he got to Paris, he should there get another. I murmured, but agreed. At Paris he could not get one. Xo Englishmen were there, and no Frenchman tit for the place could talk English to me. At Lyons he could not get one - at Montpellier he could not get one ; nor at Genoa, nor at SECRET OF MORTIFICATIOX. 27 Florence, nor at liome, nor in all Italy; and^believe at last he did not wish to get one : and we are just the same noAv as we were when he left England. This of course throws things into my duty which it was not my agreement, and is not my wish, to perform, but AA'hich are, if I remain with Sir H., unavoidable. These, it is true, are very few ; fur having been accustomed in early years to do for himself, he continues to do so at present, and he leaves very little for a valet to perform ; and as he knows that it is not pleasing to me, and that I do not consider myself as obliged to do them, lie is always as careful as possible to keep those things from me Avhich he knows would be disagreeable. But Lady Davy is of another humour. She likes to show her authority, and at first I found her extremely earnest in mortifying me. This occasioned quarrels betAveen us, at each of which I gained ground, and she lost it ; for the fretpiency made me care nothing about them, and weakened her authority, and after each she behaved in a milder manner. Sir H. has also taken care to get servants of the country, ycle])ed lacquais de place ^ to do everything slie can want, and now I am somewhat comfortable ; indeed, at this moment I am perfectly at liberty, for Sir H. has gone to Xaples to search fur a house or lodging to which we may follow him, and I have nothing to do but see Eome, write my journal, and learn Italian. But I will leave such an unprofitable subject, and tell you what I know of our intended route. For the last few weeks it has been very undecided, and at this moment there is no knowing which way we shall turn. Sir H. intended to see Greece and Turkey this summer, and arrangements were half made for the voyage ; but he has just learned that a quarantine must be performed on the road there, and to do this he has an utter aversion, and that alone will perhaps break up the journey. Since the long letter I wrote you. Sir H. has written two short papers for the Koyal Society — the first on a new solid compound of ioditie and oxygen, and the second a new gaseous 2s MICHAEL FAP.ADAY compound of chlorine and oxygen, which contains four tunes as much oxygen as euchlorine. The discovery of these bodies contradicts many parts of ( lay-Lussac's paper on iodine, which has been very much vaunted in these parts. The French chemists were not aware of the importance of the subject until it was shown to them, and no^^ they are in haste to reap all the honours attached tr. it : but their liaste opposes their aim. They reason theo- retically, without demonstrating experimentally, and errors are the result. I am. my dear Friend, yours ever and faithfully, !M. Farapay. The equivocal position thus forced upon Faradaj' by the hauteur of Lady Davy nearl}- caused a contre- temps during the stay at Geneva, which lasted from the end of June, 1814, to about the middle of September. Bence Jones's account, derived fi*om Faraday himself, is as follows : — Professor G. de la Rive, nndazzled by the brillianc}' of Davy's reputation, was able to see the true worth of his assistant. Dav}' was fond of shooting, and Faraday, who accompanied them, used to load l)avy's gun for him, while De la Rive loaded his own. Entering into conversation with Faraday, De la Rive was astonished to find that the intelligent and charming young man whom he had taken hitherto for a domestic was reall}' ixrepara- teur de lahoratoire in the Royal Institution. This led him to place Faraday, in one respect, on an equality with Davy. Whilst the}' were staying in his house, he wished them to dine together at his table. Davy, it is said, dechned, because Farada}' acted in some things as his servant. De la Rive expressed VISIT TO GENEVA. 29 his feelings strongly, and ordered dinner in a separate room for Faraday. A rumour spread years after that JJq la Rive gave a dinner in Faraday's honour : this is not so, however. Of that Geneva visit Faraday says, in 1858, to M. A. de la Rive : — • I have some such thoughts (of gratitude) even as regards your own father, Avho was, I may say, the first who personally at Geneva, and afterwards by correspondence, encouraged and by that sustained me. This correspondence, which began with the father and was continued with the son, lasted altogether nearly fifty years. From Geneva the travellers went northward, by Lausanne, Vevay, Bern, Zurich, and Schaffhausen, across Baden and Wtirtemburg to Munich. After visiting this and other German towns, they crossed Tyrol southwards to Vicenza, halting in the neigh- bourhood of the Pietra Mala to collect the in- flammable gas which there rises from the soil. They spent a day in Padua, and three days in Venice ; and on by Bologna to Florence, where Davy com- pleted his analysis of the gas collected at Pietra Mala. Early in November they were again in Rome. He writes once and again to his mother, while his anxiety about the Royal Institution makes him send inquiries to Abbott as to what is going to happen there, and to charge, him, "if any change should occur in Albemarle Street," not to forget his books which are lying there. " I prize them now more than ever." To his former master, Riebau, he wrote from Rome as follows : — 30 MICHAEL FARADAY. Eome, Jan. 5tb, ISlo. Honoured Sir, It is with very peculiar but very pleasing and indee<^ flattering sentiments that I commence a letter intended for you, for I esteem it as a bigb honour that you should not only allow but even wish me to write to you. During the whole of the short eight years that I Avas with you, Sir, and during the year or two that passed afterwards before I left England, I continually eujoyed your goodness and the eflfects of it ; and it i> gratifying to me in the highest degree to find that even absence has not impaired it, and that you are willing to give me the highest proof of (allow me to say) friendship that distance will admit. I have received both the letters that you have wrote to me. Sir, and consider them as far from being the least proofs of your goodwill and remembrance of me. Allow me to thank you humbly but sincerely for these and all other kindness, and I hope that at some future day an opportunity will occur when I can express more strongly my gratitude. I beg leave to return a thousand thanks to my kind Mistress, to Mr. and Mrs. Paine and George for their re- meuibrances, and venture to give mine with respect in return. I am very glad to hear that all are well, I am very much afraid you say too much of me to Mr. Dance, Mr. Cosway, Mrs. Udney, etc., for I feel unworthy of what you have said of me formerly, and what you may say now. Since T have left England, the experience I have gained in more diversified and extended life, and the knowledge 1 have gained of what is to be learned aud what other^i know, have sufficiently shown me my own ignorance, the degree in which I am surpassed by all the world, and my want of powers ; but I hope that at least I shall return home with an addition to my self-know- ledge. When speaking of those who are so much my superiors as Mr. Dance, Mr. Cosway, and Mrs. Udney, etc., I feel a continual fear that I should appear to want respect, but the manner in which you mention their names in your letter emboldens me to beg that you will give my humblest respects BOOKS AND BOOKSELLERS. 31 to those honoi'ed persons, if, and only if (I am afraid of intruding) they should again speak of me to you. Mr. Dance's kindness claims my gratitude, and T trust that my thanks, the only mark that I can give, will be accepted. Since I have been abroad, my old profession of books has oftentimes occurred to my mind and been productive of much ])leasure. It was my wish at iirst to purchase some useful book at every large town we came to, but I found my stock increase so fast that I was obliged to alter my plan and purchase only at Capital Cities. The first books that I wanted A\ere grammars and dictionaries, but I found few jilaces like London v/here I could get whatever T wanted. In France (at the time we were there) English books were very scarce, and also English and French books ; and a French grammar for an Englishman was a thing difficult to hnd. Nevertheless the shops appeared well stocked with books in their own language, and the encouragement Napoleon gave to Arts and Sciences extended its influence even to the printing and binding of books. I saw some beautiful specimens in both these branches at the Biblioth^ue Imperiale at Paris, but I still think they did not exceed or even equal those I had seen in London before. We have as yet seen very little of Geiinany, having passed rapidly through Switzerland and stojipino: but a few days at Munich, but that little gave me a very favorable idea of the Booksellero' shops. I got an excellent English and (ierman dictionary immediately I asked for it, and other books I asked for I found were to be had, but E. and G. Grammars were scarce, owing to the little communication between the two Em])ires, and the former power of the French in Germany. Italy I have found the country furnished with the fewest means— if books are the means of disseminating knowledge, and even A^enice which is renowned for Printing appeared to me bare and little worthy of its character. It is natural to suppose that the great and most estimable use of printing is to produce those books which are in most general use and which are required by the world at large ; it is those books which form this branch of trade, and consequently every shop in it gives an account of the more valuable state of the art (i.e.) the 32 MICHAEL FAKADAY. use ruiide of it. In Italy there are many book:>, and the shelves of the shops there appear full, but the books are old, or what is new have come from France : they seem latterly to have resigned printing and to have become satisfied with the libraries their forefathers left them. I found at Florence an E. and I. Grammar (Veneroni's), which does a little credit to Leghorn : but I have searched unsuccessfully at Rome, Naples, Milan, Bologna. Venice. Florence, and in every part of Italy for and E. an I. Dictionary, and the only one I could get was Kollasetti in Svo. E. F. and I. A circumstance still more singular is the want of bibles ; even at Rume, the seat of the Roman Catholic faith, a bible of moderate size is not to be found, either Protestant or Catholic. Those which exist are large folios or 4tos and in several volumes, interspersed with the various readings and commentaries of the fathers, and they are in the possession of the Priests and religious professors. In all shops at Rome where I ask for a small pocket bible the man seemed afraid to answer me, and some Priest in the shop looked at me in a very inquisitive way. I must now, Kind Sir, put an end to this Ittter, which I fear you will think already too long. I beg you will have the goodness to send to my blether and say I am well, and give my duty to her and my love to my brother and sisters. I have wrote four or five times lately from Rome to various friends. Remember me. if you please, to Mr. Kitchen, and others who may encpiire after me. I thank you for your concluding wishes and am, Sir. Your most dutifully. Faeaday. To his sisters he wrote also. To the elder, on the Lhurch festiYals. the CamiYal, aud the ruins of the Colosseum. To the younger, on the best way of learning French. His diary is full of the CarniYal, the foolishness of whicdi attbrded him much amuse- ment. He witnessed the horse-races in the Corso, went four tunes to masked balls, where his boyish TIIK EN'J) OK 'J'llK TOUIJ. 'Ml love of uproarious fun broke out beyond restraint, for to the last one he went disguised in a night-gown and night-cap. Between gaieties in the evenings and chemical experiments with Davy in the day, his time must have been pretty fully occupied. They had had the intention of going on to (Ireece and Turkey, but owing to dread of quarantine these projects were abandoned, and at the end of Februaiy, 1S15, they moved southwards to Naples. Here is a characteristic entry : — Tuesday, March 7th. — I heard for news that J3onaparte was again at liberty. Being no politician, I did not trouble myself much about it. though I suppose it will have a strong influence on the affairs of Europe. He went with Sir Humphry to explore Monte Somma, and ventured to make another ascent of the cone of Vesuvius, with the gratification of finding the crater in much greater activity than during the visits of the preceding year. Then, for reasons not altoirether clear, the tour was suddenly cut short. Naples was left on March 21st, Rome on 24th, Mantua was passed on 80th. Tyrol was recrossed, Germany traversed by Stuttgardt, Heidelberg, and (Jologne. Brussels w^as reached on 16th April, whence London was regained via Ostend and Deal. A letter written from Brussels to his mother positively overflows with the joy of expected return. He does not want his mother to be inquiring at Albemarle Street as to when he is expected : — You may be sure that my first moments will be in your company. If you have opportunities, tell some of my dearest D o4 MICHAEL FAUADAV. fiiends, but do uot tell everybody— that i.-, do aut trouble yourself to do it. I am of uo consequeuce except to a lew, aud there are but a few that are of consequeuce to me, and there are some whom I should like to be the first to tell myself —Mr. Eiebau for one. However, let A. know, if you can. . . Adieu till I see you, dearest Mother : and believe me ever your atiectionate and dutiful son, M. Faeaday. [P.S.] Tis the shortest and (to me, the sweetest letter I ever wrote you. A fortnight after his" return to London. Faraday was re-engaged, at a sahiry of thirty shilHngs a week, at the Pioyal Institution as assistant in the h^boratory and mineralogical collection. He returned to the scene of his former labours: but with what widened ideas ! He had had eicfhteen months of daily inter- course with the most brilhant chemist of the age. He had seen and conversed with Ampere, Arago, Gay-Lussac, Chevreul, Dumas, Volta, De la Rive, Biot. Pictet, De Sausstire. and De Stael. He had formed a lasting friendship with more than one ot these. He had dined with Count Rumford, the founder of the Royal Institution. He had gained a certain mastery over foreign tongues, and had seen the ways of foreign society. Though it was many A'ears before he again quitted England for a foreign tour, he cherished the most hvelv recollection ot manv of the incidents that had befallen him. CHAPTER IL LIFE AT THE ROYAL INSTITUTION. Amongst the scientific societies of Great Britain, the Royal Institution of London occupies a con- spicuous place. It has had many imitajtors in its time, yet it remains unique. A " learned society " it may claim to be, in the sense that it publishes scientific transactions, and endeavours to concentrate within itself and promote the highest scieiice, within a certain range of subjects. In some respects it re- sembles a college ; for it appoints professors, and provides them with space, appliances, and materials for research, and a theatre wherein to lecture. For its members it provides a comfortable, well-stocked library, and a reading-room where daily and periodic journals may be consulted. But it has achieved a reputation far in excess of any it would have held, had that reputation depended solely on its publica- tions, or on the numerical strength of its membership. Founded in the 3^ear 1799 by that erratic genius Count Ruinford, as a sort of technical school,* it would speedily have come to an end had not others stepped in to develop it in new ways. From the certain ruin which seemed impending in 1801, it was * The meeting at which it was actually originated was held under the ijresidency of Sir Joseph Banks, P.R.S., nominally as a meeting for the Assistance of the Foot ! ob ^t[^.HAEL KAUAI >AV. saved by the appearance upon the scene of the briUiant youth Humphry Davy, whose lectures made it for ten years the resort of fashion. In 1^14 it was again in such low water that Faraday, traveUing on the Continent at that time as amanuensis to Sir Humphry, was every n\onth expecting to hear of its collapse. Until about 1833, when the two FuUerian Professorships were founded, it was continually m rinancial ditticulties. The persistent and extraordinary ehorts made by Faraday from 182G to 1839; and the reputation of the place Avhich accrued by his dis- coveries, were be^'ond all question its salvation from ruin. When it was founded it was located in two private houses in Albemarle Street, then regarded as quite out of town, if not almost suburban: the premises being altered and an entrance hall ^ntll staircase added. A httle later the lecture- theatre, much as it still exists, was constructed. The exterior at lirst remained unchanged. The stucco pilasters of Grecian style, which give it its ah of distinction, were not erected until 1838. The fine rooms of the I)avy-Faraday laboratory at the south end were only added in 1896 by the liberality of Mr. Ludwig Mond. Besides the laboratories for research in physical chemistry, Avhich have thus been associated with the older part of the Institution, additional rooms for the library have been provided in this munificent cr-ift to science. The older laboratories of the Institution, though they retain some features from Rumford's time, have been considerably remodelled The old rooms where Dav}', Young, Brande, Faraday, Frank- land, and T^^ldaIl conducted then- researches are still KOYAL INSTITUTION LAIJOKATORIES. 87 in existence ; but the chief laboratory was recon- structed in 1872 in Tjaidall's time ; and it has been quite recently enlarged and reconstructed to accom- modate the heavy machinery required in Professor Dewar's researches on liquid air and the properties of bodies at low temperatures. The spirit of the place ma}^ be sunjmed up very briefly. It has existed for a century as the home of the highest kind of scientific research, and of the best and most specialised kind of scientitic lectures. It was here that Davy fij-st showed the electric arc lamp : that he astonished the world by decomposing potash and producing potassium; that he invented the safety lamp. It was here that Faraday \vorked and laboured for nearly Mlty years. Here that Tyndalls investigations on radiant heat and diamagnetism were carried on. Here that Brande, Frankland, Odling, Gladstone, and Dewar have handed on the torch of chemistry from the time of Davy. Professorships, of which the educational duties are restricted to a few lectures in the year, giving leisure and scope for research as the main dut}^ are not to be found anywhere else in the British Islands ; those at colleges and universities being invariably hampered Avifch educational and administrative duties. As for the lectures at the Pioyal Institution, they may be divided under three heads : the afternoon courses; the juvenile lectures at Christmas; the Friday night discourses. The afternoon lectures are thrice a week at three o'clock, and consist usually of short courses, from three lectures to as many as twelve, by eminent scientific and literary men. Invariably 38 MICHAEL FARADAY. one of these courses during the season, either before or after Easter, is given by one of the regular Pro- fessors ; the remaining lecturers are paid professional fees in proportion to the duration of their course. The Christmas lectures, always six in number, are given, sometimes by one of the Professors, sometimes by outside lecturers of scientific reputation. But the Friday night discourses, given at nine o'clock, during the season from January till June, are unique. Xo fee is paid to the lecturer, save a contribution toward expenses if applied for, and it is considered to be a distinct honour to be invited to crive such a discourse. There is no scientific man of any origii:ial claim to distinction: no chemist, engineer, or electrician: no phvsioloo'ist, creoloo^ist, or mineralooist, during the last fifty years, who has not been mvited thus to give an account of his investio^'ations. Occasionallv a wider range is taken, and the eminent Avriter of books, dramatist, metaphysician, or nuisiciau has taken his place at the lecture-table. The Friday night gather- ing is always a brilliant one. From the salons of society, from the world of politics and diploiiiacy, as well as from the ranks of the learned professions and of the tine arts, men aiid women assemble to listen to the exposition of the latest discoveries or the newest advances in philosophy' by the men who have made them. Every discourse must, so far as the subject admits, be ilhistrated in the best possible way by experiments, by diagrams, by the exhibition of specimens. Not infrequently, the person invited to give a Friday evening discourse at the Royal Institu- tion will begin liis preparations live or six months THE FAMOUS I.KrTrUES. 39 beforehand. At least one instance is known — the occasion being a discourse by the late Mr. Warren De la Rue — where the preparations were begun more than a 3^ear beforehand, and cost several hundreds of pounds. And this was to illustrate a research already made and completed, of which the bare scientific results had already been communicated in a memoir to the Royal Society. A mere enumeration of the eminent men Avho have thus given their time and labours to the Royal Institution would till many pages. It is little cause for wonder then that the lecture- theatre at Albemarle Street is crowded week after week in the pursuit of science under condi- tions like these ; or that every lecturer is spurred on by the spirit of the place to do his subject the utmost justice by the manner in which ho handles it. There are no lectures so famous, in the best sense of the word so popular, certainly none sus- tained at so high a level, as the lectures of the Royal Institution. But it was not always thus. Davy's brilliant but ill-balanced genius had drawn fashionable crowds to the morning lectures which he gave. Brande proved to be a much more humdrum lecturer ; and though with young Faraday at his elbow he found his work of lecturing a task " on velvet," he was not exactly an inspiring person. During Davy's protracted tour abroad things had not altogether prospered, and his return was none too soon. Faraday threw himself whole-heartedly into the work of the Institution, not only helping as lecture assistant, but giving a hand also in the preparation of the Quarfaiif 40 JllCIIAEL FAKAPAV. JoHi-ti(d of Science, which had been cstabhshcd as a kind ot'journal of proceedings. But now Faraday was to take a quiet step forward. He appears at the City Philosophical Society in the character of lecturer. He oave seven lectures there, in 1816, on chemistry, the fourth of them being "On Radient Matter." Extracts arc oiyen from most of these lectiu'cs in Bence Jones's " Life and Letters of Faraday " ; they show all that love of accuracy, that Ithilosophic suspense of judgment in matters of liypothesis, which in after 3'"ears were so characteristic mF the man. He alsi ) l;cpt a c< )i in uonplacc b( )ok tilled Avith II' ties of scientific matters, with literary excerpts, ;uiagrams, epitaphs, algebraic puzzles, varieties of spelling of his own name, and personal experiences, including a poetical diatribe against falling in love, together with the following more prosaic aphorism : — What iy Love ? — A nuisance to everybody but the parties concenied. A private aflair which every one but those con- cerned wishes to make public. It also includes a piece in verse, by a member of the City Philosophical Society -^a Mr. Dryden — called '■ <^)uarterly Night," which is interesting as embalming a portrait of the youthful Faraday as he appeared to his coim'ades : — Neat was the youth in dress, in person phiin ; His eye read thus, Phllomplw in (jrain; Of understanding clear, reflection deep ; Expert to apprehend, and strong to keep. His watchful mind no subject can elude, Nor s])ecious arts of sophists ere delude ; CITY PHILOSOrHlOAL SOCIETY. 41 His powers, unshackled, range from pole to pole ; His mind from error free, from guilt his soul. Warmth in his heart, good humour in his face, A friend to mirth, but foe to vile grimace ; A temper candid, manners unassuming, Always correct, yet always uniiresuming. Such was the youth, the chief of all the lj;uid ; His name well known, Sir Hum]fhry"s right hand. At this date there were no evening duties at the Royal Institution, but Faraday found liis evenings w^ell occupied, as he explains to Abbott when rallied about his having deserted his old friend. Monday and Thursday evenings he spent in self-improvement according to a regular plan. Weduesda3\s he gave to " the Society " (i.e. the C'ity Philosophical). Satur- days he spent with his mother at Weymouth Street ;■ leaving only Tuesdays and Fridays for his own business and friends. And so the busy months pass, and he gives more lectures in the privacy of the n oratory by the elocutionist Mr. B. H. Suiart, paying (jut of his slender resources half a guinea a lesson, so anxious was he to improve himself, even in his manner of lecturing. His notes on these lessons fill 133 manu- script pages. His other notes now begin to ]3artake less of the character of quotations and excerpts, and more of the nature of queries or problems for solution. Here are some examples ; — '■ Do the pith balLs diverge by the disturbance of electricity in consequence of mutual induction or notT' 44 :\ncHAEL fahaday. ^ " Distil oxalate of ammonia. Query, results? " " Query, the nature of the body Phillips Iturns in his spirit lamp?" The Phillips here lUGiitioiied was the chemist Richard Phillips (aftenvards President of the Chemi- cal Society), one of his City friends, whose name so frequently occurs in the correspondence of P'araday's middle life. Phillips busied himself to promote the material interests of his friend Avho — to use his own language — was " constantly engaged in observing the Avorks of Nature, and tracing the manner in which she directs the arranc^ement and order of the Avorld," on the splendid salary of £100 per annum. The folloAV- ing note in a letter to Abbott, dated February 27, 1818, reveals new professional labours : — I lia\'e been more than enough employed. We have l)een ubli^^ed even to put aside lectures at the Institution ; and noAv 1 am so tired with a long attendance at (luildhall yesterday and to-day, being siibpronaed, with Sir H. Davy, ■Mr. Brande, Phillips, Aikin, and others, to give chemical information on a trial (which, however, did not come off), that 1 scarcely know what I say. Shortly afterwards Davy again went abroad, but P^iraday remained in England. From Rome Davy Avrote a note, the concluding sentence of which shows how Faraday was advancing in his esteem. — Kome : October, 1818. Mr. Hatchett's letter contained praises of you wliich were very gratifying to ine ; for, l)elieve me, there is no one more interested in your success and welfare than your sincere well- wisher and friend, H. Davy. BEGINS ORIGINAL TtESEAUGHES. 45 Li the next year Davy wrote again, suggesting to Faraday that he might possibly be asked to come to Naples as a skilled chemist to assist in the unrolling of the Herculaneum manuscripts. In May he wrote again, from Florence : — It gives me great plea.^ure to hear that you are comfortable at the Royal Institution, and I trust that you will not only do something good and honourable for yourself, but likewise for science. I am, dear Mr, Faraday, always your sincere friend and well-wisher, H. Davy. The wish that Davy expressed that Farada}' might ^' do soniething" for himself and likewise for science was destined soon to come to fulfilment. But in the case of one who had worked so closely and had been so intimately associated as an assistant, it imist necessarily be no easy matter always to draw a distinction between the work of the master and that of the assistant. Ideas suggested by one might easily have occurred to the other, when their thoughts had so long been directed to the same ends. And so it proved. Reference to Chapter III. will show that alread}^, beginning in 1816 with a simple anal3'sis of canstic lime for Sir Humphry Davy, Faraday had become an active worker in the domain of original research. The fascination of the quest of the unknown was already upon him. While working with and for Davy on the properties of flame and its non-transmission through iron gauze^ in the investigation of the safety lamp, other problems of a kindred nature had arisen. One 46 MiriIAi:i. FARAIJAY. of tliGso, relating to the tlow of gases through capillary tubes, Faraday had attacked by himself in 1 817. The subject formed one of the six original papers which he published that year. In the next two years he contributed in all no fewer than tliirty-seven papers or notes to the Qicarterlij Joiir'aal of Science. In ISIO began a long research on steel which lasted over the year 1820. He had already given evidence of that dislike of lialf-truths, that aversion for "doubtful knowledge " which marked him so strongly. He had exposed, with ipiiet but unsparing success, the empti- ness of the claim made by an Austrian chemist to have discovered a new metal, " Sirium," by the simple device of analysing out from the mass all the con- stituents of known sorts, leaving Ijehind — nothing. And now, Faraday being twenty-nine years of age, a new and all-important episode in his life occurred. Amongst the members of the little congregation which met on Sundays at Paul's Alley, Red Cross Street, was a Mr. Barnard, a working silversmith of Paternoster Row, an elder in the Sandemanian body. Ho had t W(j sons, Ed ward Barnard , a fri end of Faraday's, and George, who became a well-known water-colour artist ; and three daughters ; one who was already at this time married; Sarah, now twenty-one years of age ; and Jane, Avho was still younger. Edward had seen in Faraday's note-book those boyish tirades against falling in love, and had- told his sister Sarah of them. Nevertheless, in spite of all such misogynistic fancies, Faraday woke up one day to find that the large-eyed, elear-browed girl had grown to a place in his heart that he had thought barred HE FALLS IN LO\'E. -i ' against the assaults of love. She asked him on one occasion to show her the rhymes against love in his note-book. In repl}^ he sent her the hitherto un- published poem : — 11. L Oct. nth, 1819. You ask'd me last night for the lines \vhich I penn'd, When, exulting in ignorance, tempted by pride, I dared torpid hearts and cold breasts to commend, And ati'ection's kind pow'r and soft joys to deride. If you urge it I cannot refuse your request : Though to grant it will punish severely my crime : But my fault I repent, and my errors detest ; And I hoped to have shown ni}' conversion in time. hemember, our laws in their mercy decide That no culprit be forced to give proof of his deed : They protect him though fall'n, his failings they hide, And enable the wretch from his crimes to receed (.s/c). The principle's noble I I need not urge long Its adoption ; then turn from a judge to a friend. Do not ask for the proof that I once acted wrong, """< But direct me and guide me the way to amend. M. F. What other previous passages bet\veen them are hinted at in the letter "which he sent her, is unknown ; but on July 5, 1S20, he Avrote : — Koyal Institution. You know nie as well or better than I do myself. Y'ou know my former prejudices, and my present thoughts — you know my weaknesses, my vanity, my whole mind ; you have converted me from one erroneous way, let me hi^ipe you will attempt to correct what others are wrong. Again and again I attempt to say what 1 feel, but I cannot. 48 MK'TIAEL KAIJAPAV. Let iiiL', howevei-, claim not to bo the selfish Iteing tluit wishes to l^end your aHections for his own sake only. In whatever way I can best minister to your ha])piness eitlier l)y assiduity or l)y absence, it shall 1)0 i\nue. Do not injure me by withdrawing your friendsliip, or punish nn; b^- aiming to be more than a friend by making me less ; and if you cannot grant me more, leave me what I possess, but hear me. Sarah Barnard sliowcd the letter to lier father. She was 3'ounL^\ and feared to aecept her lover. All her father would say by Avay of counsel was that bjve made philosophers say many foolish thint^^s. The intensity of Faraday's passion proved for the time a. bar to his advance. Fearing lest she should be unable to return it with equal force, Miss Barnard shrank from replying. To postpone an immediate decision, she went away with her sister, Mrs. Reid, to Ramsgate. Faraday followed to press his suit, and after several liappy days in her company, varied with country walks and a run over to Dover, he was able to say : "Not a moment's alloy of this evening's happiness occurred. Everything was delightful to the last moment of my stay with my companion, because she was so." Of the many letters that Faraday Avrote to his future wife a number have been preserved. They arc manly, simple, full of quiet affection, but absolutely free from gush or forced sentiment of any kind. p]xtracts from several of them are printed by ]>ence Jones. One of these, written early in 1821, runs as follows : — I tied np the enclosed key with my books last night, and make haste to return it lest its absence should occasion A HAPI'V MAUKIAUE. 40 confusion. If it haw, it Avill perhaps remind you of the disorder I nRi:st be ill here also for the want of a key— I mean the one to my heart. However, I know where my key is, and hope soon to have it here, and then the Institution will be all right again. Let no one oppose my gaining possession of it Avhen unavoid- able obstacles are removed. Ever, my dear girl, one who is ]ierfectly yours, M. Fakaday. Faraday obtained leave of the managers to bring his wife to live in his rooms at the Institution ; and in May, 1821, his position Avas changed froiu that of lecture assistant to that of superintendent of the house and laboratory. In these changes Sir Humj^hry Davy gave him w'illing assistance. But his salary reniained £100 a year. Olistacles being now removed, Faraday and Miss Bat^nard were married on June 12. Few persons were asked to the wedding, for Faraday Avished it to be "just like any other day." " There Avill," he Avrote, " be no bustle, no noise, no hurry. ... it is in the heart that we expect and look for pleasure." His marriage, though childless, Avas extremely ^^^^PP3'- ^^^'^- Faraday proved to be exactly the true helpmeet for his need : and he loved her to the end of his life Avith a chivalrous devotion Avhich has become almost a proverb. Little indications of his attachment crop up in miexpected places in bis subsequent career ; but as Avith his religious vicAvs so Avith his domestic affairs, he never obtruded then upon others, nor yet shrank from mentioning them "when there was cause. Tyndall, in alter years, made the intensity of Faraday's attachment to his Avife the E 50 MICHEAL FAltADAV. subject of a strikinG: simile : " Never, I believe, existed a manlier, purer, steadier love. Like a burnmg diamond, it continued to shed, for six and forty years, its white and smokeless glow." In his diploma-book, now in possession ot the Royal Society, in which he carefully preserved all the certificates, awards, and honours bestvowed upon him by academies and universities, there may be found on a slip inserted in the volume this entry ; — 25tli January, 1847. Amongst these records and events, I here insert the date of one which, as a source of honour and hapi)ines8, far exceeds the rest. We were married on June 12, 1821. M. Faraday. And two yea>rs later, in the autobiographical notes he Avrote : — On June 12, 1821, he married— an event which more than any other contributed to his earthly happiness and healtlitul state of mind. The union has continued for twenty-eiglit years, and has nowise changed, except in the depth and strength of its character. ^\'hen near the close of his life, he presented to the Eoyal Institution the bookcase with the volumes of notes of Davy's lectures and of books bound by himself, the inscription recorded that they were the ^nft of " Michael avxi. Sarah Faraday-." Every Saturday evening he used to take his wife to her father's house at Paternoster Plow, so that on Simday they should be nearer to the chapel at Paul's Alley. And in after years, when he was away on scientific work, visiting lighthouses, or attendino- FIRST ELECTRICAL DISC-*.)VERV. -51 meetiii^^s ot* the Britif^h Association, he alwavs tried to return tor the Sunday. A let':er tL'om Licbig in lS4-lr {see p. 225) gives one of the very few gKnipses of conteuiporary date of the impression made by Mrs. Faraday upon others. One month alter his marriage Faraday made his profession of faith before the Sandemanian church, to Avhich his wife ah'eady belonged, and was admitted a member. To his rehgious views, and his rehitions to the body he thus formally joined, reference will be found later. Faraday now settled down to a routine life oi scientitic work. His professicaial reputation was rising, and his services as analyst were being sought atter. But in the midst of this he was pursuing invest igatii:>ns on his own account. In the late summer o( this year he made the discovery oi the electro-magnetic rotations desci'ibed in Chapter IIL — his hrst important piece of original research — and had in consequence a serious misunderstanding with I'r. WoUaston. On September ord. working' with George Barnard in the laboratory, he saw the electric wire for the lirst time revolve around the pole of the magnet. Paibbing his hands as he danced around the table with beaming face, he exclaimed : " There they go ! there they go '. we have succeeded at la^t."" Then he gleefully proposed that they should wind up the day by going to one of the theatres. Which should it be f '' Oh. to Astley's. to see the horses." And to Astley's they went. (Jn Christmas T»ay he called his young Avife to see something new : an electric couductino'-wire revolvinir under the inliuence of the 52 MICHAEL FARADAY. iiiagnetisui of the earth alone. He also read two chemical papers at the Royal Society, announcing new discoveries ; one of them in conjunction with his friend Phillips. In July, lcS22, he took his wife and her mother to Rams<]fate, whilst ho went off with Phillips to Swansea to try a new process in Vivian's copper -works. During this enforced parting, Faraday wrote his wife three letters from which the folloAving are extracts : — ■ (July 21, 1822). I })erceive that if I give way to my thoughts, I shall write you a mere love-letter, jast as usual, with not a particle of news in it : to prevent which I will constrain myself to a narrative of what has happened since I left you up to the present time, and then intkilge my alfection. ^'esterday was a day of events— little, but pleasant. I went in the morning to the Institution, and in the course of the day analysed the water, and sent an account of it to Mr. Hatchett. Mr. Fisher I did not see. Mr. Lawrence called in, and Vtehaved with his usual generosity. He had called in the early part of the Aveek, and, finding that I should be at the Institution on Saturday only, came up, as I have already said, and insisted on my accepting two ten-pound bank-notes for the information he professed to have ol)tained from me at various times. Is not this handsome? The money, as you know, could not have been at any time more acceptable ; and I cannot see any reason, my dear love, why you and I should not regard it as another proof, among many, that our trust should without a moment's reserve be freely reposed on Him who provideth all things for His peofile. Ha\e we not many times been re))roached, by tucli mercies as these, for our caring after food iind raiment and the things of this world ? On coming home in the evening, /.c, coming to Paternoster Ro-\v home, I learned that ]\Ir. Phillips had seen C, and had told her we siuiuhl nut leave London until Monday evenin<^. '' A MERK LOVK-J.ETTEK." 53 So I shall ]iave to-morrow to get things ready in, and I shall have enough to do. I fancy we are going to a large mansion and into high company, .so I must take more clothes. Having the £20, I am hecorae bold And now, how do my dear wife and mother do ? Are you conifortable *? are you happy? are the lodgings convenient, and Mrs. O. obliging? Has the phice done you good I Js tlic weather fine? Tell me all things as soon as you can. I think if you write directly you get this it will be best, but let it be u long letter. I do not know when I wished so nuich foi' a long letter as 1 do from you now. You will get this on Tuesday, and any letter from you to nie cannot reach Swansea before Thursday or Friday— a sad long time to wait. Direct t(j me, Post Otfice, Swansea ; or perhaps better, to me at — Vivian Esq., Marino, near Swansea, South Wales And now, my dear girl, I must set business aside. I am tired of the dull detail of things, and want to talk of love to you; and surely there can be no circumstances under which 1 can have more right. The theme was a cheerful and delightful one before we were married, but it is doubly so now. I now can speak, not of my own heart only, but of both our hearts. I now speak, not with any doubt of the state of your thoughts, but with the fullest conviction that they answer to my own. All that I can now say warm and animated to you, 1 know that you would say to me again. The excess of pleasure wbicli I feel in knowing you mine is doubled by the cunscionsness that you feel equal joy in knowing me yours. Marino : Sunday, July 28, 1822. My dearly beloved Wife,— I have just read your letter again, preparatory to my writing to you, that my thoughts might be still more elevated and quickened than before. 1 could almost rejoice at niy absence from you, if it were only that it has produced such an earnest and warm mark of affection from you as that letter. Tears of joy and delight fell from my eyes on its perusal. I think it was last Sunday evening, about this time, that I wrote to you from London ; and I again resort to this affectionate cnnversation with ynn, 54 MICHAEL FAltADAV. to tell you Avhat Las happened since the letter which I got franked from this place to you on Thursday I believe. We have been working very hard here at the copper works, and with some success. Our days have gone on just as before. A walk before breakfast ; then breakfast ; then to the works till four or five t)'clock, and then home to dress, and dinner. After dinner, tea and conversation. I have felt doubly at a loss to-day, being absent from both the meeting and you. When away from London before, I liave had you with me, and we could read and talk and walk ; to-day 1 have had no one to fill your place, so I will tell you how I have done. There are so many here, and their dinner so late and long, that I made up my mind to avoid it, though, if possible, without appearmg singular. So, having remained in my room till breakfast time, we all breakfasted together, and soon after j\[r. Phillips and myself took a Avalk out to the Mumbles Point, at the extremity of this side of the ba3^ There we sat down to admire the beautiful scenery around us, and, after we had viewed it long enough, returned slowly home. We stopped at a little village in our way, called Oystermouth, and dined at a small, neat, homely house about one o'clock. We then came back to Marino, and after a little while again went out — Mr. Phillips to a relation in the town, and myself for a walk on the sands and the edge of the bay. I took tea in a little cottage, and, returning home about seven o'clock, found them engaged at dinner, so came up to my own room, and shall not see them again to-night. I went down for a light just now, and heard them playing some sacred music in the drawing-room; they have all been to church to-day, and are what are called regular people. The trial at Hereford is put off for the present, but yet we shall not be able to be in town before the end of this week. Though I long to see you, I do not know when it will be ; but this I know, that I am getting daily more anxious about you. Mr. Phillips wrote home to Mrs. Phillips from here even before I did— /.^. last Wednesday. This morning he received a letter FROM HUSJiAND T(J WIPE. 55 from Mrs. Phillips (who i« very well) desiring him to a.sk me for a copy of one of my letters to you, that he may learn to write love-lettei'S of sufficient length. He laughs at the scold- ing, and says that it does not hurt at a distance It seem.s to lue so long since I left you that there must li;ive been time for a great many things to have happened. I expect to see you with such joyAvhen I come home that I shall hardly know what to do with myself. I hope ytiu will be well and blooming, and animated and hap]»y, when you see me. I do not know how we shall contrive to get away from here. We certainly slmll not have concluded before Thursday even- ing, but T think we shall endeavour earnestly to leave this place on Friday night, in which case we shall get home late on Saturday night. If Ave cannot do that, as I should not like to be travelling all day on Sunday, we shall probably not leave until Sunday night ; but I think the first plan will be adopted, and that you w^ill not have time to answer this letter. I expect, nevertheless, an ani^wcr to my last letter— /.f. I expect tliat ray dear wife will think of me again. Expect here means nothing more than I trust and have a full confidence that it Avill be so. My kind girl is so allectionate that she would not think a dozen letters too niuch for me if there were time to send them, which I am glad there is not. Give my love to our mothers as earnestly lis you would your own, and also to Charlotte or John, or any such one that you may have Avith you, I have not Avritten to Paternoster Row yet, but I am going to write now, so that I may be permitted to finish this letter here. I do not feel , Faraday wrote to Philhps :— A thousand thanks to you for your kindness — I am delighted with the names — Mr. Brande had told me of it before I gut your note and tlionght it impossible to be better. I suppose you will not be in Grusvenor Street this Evening, so I will ])ut this in the post. Our P>est remembrances to Mrs. Phillips. ^^our^ Ever, M. Faraday. The certiiicate was read for the first time on May 1st. The absence of the names of Davy and Brande is accounted for by the one being President and the other Secretary. Bence Jones gives the foHowing account of what followed: — Tliat Sir H. Davy actively opi)Osed Faraday's election is no less certain than it is sad. ^lany years ago, Faraday gave a friend the fnllnwing facts, 58 MICHAEL FARAIXAY. which were ^vritten down iiiiinediately : — " Sir H. Davy told me I must take down my certificate. I replied that I had not put it up ; that I couhl not take it down, as it was put up by my proposers. He then said I must get my iiroposers to take it down. I answered that 1 knew they would not do so. TIkmi ]ie said, 1 as PrL-sident will take it down. I replied that I was sure Sir H. Davy would do what he thought was for the :j,ood of the Koyal Society.' Faraday also said that one of his proposers told him that Sir H. Davy had walked for an hour round the courtyard of Somerset House, arguing that Faraday ought not to be elected. This was probably about May .3". Faruda}' also made the following notes on the circumstance of the charge made by Wollaston's friends :— 1823. In rd'.ition tu Dooiia oj'posituyji to imj election at the Eoi/al Society. Sir H. Davy angry, May 3o. Phillips' report through Mr. Children, June o. ^Ir. Warburton called hrst time, June 5 (evening). 1 culled on Dr. AVollaston, and he not in titwn, June 9. I called on Dr. Wollaston, and saw him, June 14. I called at Sir H. Davy's, and he called on me, June 17. On July S Dr. Warburton wrote that he was satisfied with Farada3''s exphination, and added that he would tell his friends that " my objections to you as a Fellow are and ou^dit to be withdraAvn, and that I now w^ish to forw^ard your election." Bence Jones adds : — On June i29, Sir H. Davy ends a note, "I am, dear Faraday, very sincerely your well wisher and friend.'' So that outwardly the storm rapidly passed away ; and when the ballot was taken, after the certificate had been read at ten meetings, there was only one black ball. KELLOWSHLL' AND MAGNANIMITY. 50 The election took place January 8, 1824. Of this unfortunate misunderstanding-,"^'" Davy's biographer, Dr. Thorpe, writes :— The jealousy tlius manifested by Davy is one of the most ])itiful facts in his history. It was a sign of that moral weak- ness which Avas at the bottom of much of his unpopularit}', and which revealed itself in various ways as his physical strengtli decayed." . . . ■ Faraday allowed himself in after days no shade of resentment against Davy; though he confessed rather sadly that after his election as F.B.S. his relations with his former master were never the same as before. If anyone recurred to the old scandal, he "would hre with indignation. Dumas in his " Eloge Historiquo " has given the following anecdote: — Fai aday never forgot Avhat he owed to Davy. Visiting him at the family lunch, twenty years after the death of the latter, he noticed evidently that I responded with some coolness to the jjraises which the recollection of Davy's great discoveries had evoked from him. He made no comment. But, after the meal, he simply took me down to the library of the Iloyal Institution, and stopping before the t»ortrait of Davy he said : " He Avas a great man, Avasrft he?" Then, turning round, lie added, "It was heref that he spoke to me for the first time." I boAved. We Avent down to the laboratory. Faraday took * A Avritor in the Quarierlij Jonrncd of Science for 1868, p. 50, f-;n s : " Wo have leason to know that Davy Avas shghtly annoyed that the certificate proposing Faraday foi' election should have originated with liichard Phillips, and that he should not have heen consulted before that gentleman was alloAved to take the matter in hand." This is absurd, because the President was by long-standing etiquette deliaircd fi'oni signing Ihe certificates of any but foreign members, as the certificate book (if the Royul Socipty attests. t Seep. I'l. (iO MICHAf:L FAKADAV. out a note-book, (jptued it and pointed out with bis finger the ■words written by Davy, at the very moment when l-y means of the battery he had just decomposed potasli, and had seen the first globule of potassium ever isolated Ijythe hand of man. Davy had traced with a feverish liand a circle which separates them from the rest of the fiage : the words, '•' Capital Experi- ment,'' which he wrote belnw, cnnnot be read without emotion by any true chemist. I confessed myself conquered, and this tmie, without hesitating longer, L jnined in the admiration :<.'\ hoyal Iiistitutinn, June -21, 1831. My dear Phillips, — 1 liaA^e been tryiiiA' liard to get time enough to write to you Iiy post to-niglit, l.tut without success ; the Vtell has riuig, and I am too Lite. Hu^ve^■e^, 1 am resolved to be ready to-morrow. \Ve liave l)ee]i Aery anxious and rather embarrassed in our minds about your anxiety to know how things Avere i)roceeding, and uncertain Avhother reference to them woukl be pleasant, and that has heen the cause Avhy I h'J. MICHAEL FARADAY. have not written to yon, for I did wm know whu character your connexion with Badanis had. I was a little the more embarrassed because of my acquaintance with Mr. Rictard and hi> family, and, of course with his brother-in-law. Dr. Urchell, of whom I have made numerous enquiries to know what Mr. Kiekard intended doing at Birmingham. He (expressed a) hope it would be nothing unpleasant tn you, but was m>t sure. Our only bit of comfort in the matter was on hearing from Daniell about you a little : he was here to-day. and glad to hear of you through me. But now that I may write, let me say that Mrs. Faraday has been very anxious with myself, and begs me earnestly t-? remember her to Mrs. Phillips. We have often wished we could have had you here for an hour or two. to break off what we supposed might be the ti-ain of thoughts at home. With regard to the five guineas, do not think of it for a moment. Whilst I supposed a mercantile concern wanted my opinion ivv its own interested uses, I saw no reason why it should not pay me : but it is alt^jgether another matter when it becomes your on'air. I do not think you would have wished me to pay you five guineas for anything you might have done personally for me. " Dog don't eat dog," as Sir E. Home said t'"> me in a similar case. The affair is settled. I have no doubt I >hall be amu-^ed and, as you speak of new facts, instructed by your letter to Dr. Eeid, as I am by all your letters. Daniell says he thinks you are breaking a tly upon the wheel. You know I consider you as the Prince of Chemical critics. Pearsall has been working, as you know, on i*ed man- ganese solutions. He has not proved, but he makes out a .strong case for the opinion, that they owe their colour and other properties to manganesic acid. This paper will be in the next numV»er of the Journal. With regard to the gramme, wine-pint, etc.. etc., in the manipulation I had great trouble about them, for I could find no agreement, and at last resolved to take certain conclusions from Capt. Katers paper and the Act of Parliament, and calculate the rest. I think I took the data at i»age 67 SACRIFICES Foil SCIEXi'i:. Ho ]iar;i,i;rapli lU). ns the data, but am not sure, and cannot ,£:o over them again. My memory gets worse and worse ihiily. I will not, therefore, say 1 have not received yonr JMi.u-macopa-ia — that of 1824 is what I have at hand and use. I am nut aware of any other. I have sent a paper to the If. .S., but not chemical. It is on sound, etc., etc. If they pri]it it. of course you will have a copy in due time. I am, my dear Philliits, Most faithfully and sincerely yours, 'M. Faraday. Is it right to ask what has berome of Badams ''. I sujipose he is. of coarse, a defaulter at the K. S. This sacrifice for science Avas not small. He had made £1,000 in LS30 out of these professional occupations, and in 1S3I would have made more but for his own decision. In 1S32 some Excise work that he had retained brought him in £155 9s. : but in no suftsequent year did it bring in so much. He might easily have made £5,000 a year had he chosen to cultivate the professional connection thus formed : and as he continued, with little intermission, in activity till 18li0, he might have died a wealthy man. But he chose otherwise ; and his first reward came in the au t umn of 183 1 , in t he great discovery of magneto-electric currents — the principle upon which all our modern dynamos and transformers are based, the foimdation of all the electric lighting and electric transmission of power. From this work he went on to a research on the identity of all the kinds of electricity, until then supposed to be of separate sorts, and from this to electro-chemical work of the very 04 :\11LHAEL FAKAOAV. luGcliest value. endent feeling from the acceptance of them, but will add a higher value to the grant of a pension as an honourable distinction than any that it could derive from its pecuniary amount. Ever, my dear Ashley, Most faithfully yours, PiOBERT Peel. Sir James South still endeaYourecl to bring about the grant thus deferred, and wrote to the Hon. Caroline Fox, asking her to put the historiette of Faraday in the hands of Lord Holland, for hiui to lay before Melbourne. Faraday at first demurred to Sir James Souths action, but on the advice of his father-in-law, Barnard, withdrew his demurrer. Later in the year he was asked to wait on Lord Melbourne at the Treasury. He has left a diary of the events of the day, October 26th. According to these notes it LORD Melbourne's participle. 71 appears that Faraday first had a long talk with Melbourne's secretary, Mr. Young, about his first demurring on religious grounds to accept the pension, about his objection to savings' banks, and the laying- up of wealth. Later in the day he had a short inter- view with the First Lord of the Treasury, when Lord Melbourne, utterl}^ mistaking the nature of the man before him, inveighed roundly upon the Avhole system of giving pensions to scientific and literary persons, which he described as a piece of humbug. He pre- fixed the word " humbug " with a participle which Faraday's notes describe as *' theological." Faraday, with an instant flash of indignation, bowed and with- drew. The same evening he left his card and the following note at the Treasury : — To the Right Hon. Lord Vucount Melbourne^ First Lord of the Treasury. October 26. My Loed, — The conversation Avitli which your Lordship honoured me this afternoon, including, as it did, your Lord- ship's opinion of the general character of the pensions given of late to scientific persons, induces me respectfully to decline the favour wliich I Ijelieve your Lordship intends for me ; for I feel that I could not, witli satisfaction to myself, accept at your Lordship's hands that which, though it has the form of approbation, is of the character wliich your Lordship so pithily applied to it- Faraday's diary says : — Did not like it much, and, on the whole, regret that friends should have placed me in the situation in which I found myself. Lord Melbourne said that "he thought there had been a great deal of humbug in the whole affair. He did not ri MICHAEL FARADAY. mean my affair, of course, but that of the pensions altogether." ... I begged him to understand that I had kno-u-n nothing of the matter until far advanced, and, though grateful to those friends who had urged it forward, wished him to feel at perfect liberty in the affair as far as I was concerned. . . In the evening I Avrote and left a letter, I left it myself at ten o'clock at night, being anxious that Lord Melbourne should have it before anything further was done in the affair. However, the matter did not end here. Faraday's friends were indignant. A caustic, and probably exaggerated, account — for wliicli Farada}^ disclaimed all responsibility — of the interview appeared in Frasers Macjazine, and was copied into TJte Times of Novem- ber 28th, with the result that, had it not been for the personal intervention of the King, the pension might have been refused. The storm, however, passed away, and the pension of £300 per annum was ^•ranted on December 24th. Years afterwards, writins^ to j\Ir. B. Bell, Faraday said, " Lord Melbourne behaved very handsomely in the matter." In Fraser's Magazine for February, 1886 (vol. xiii., p. 224), is a portrait of Faraday by Maclise, accompanied by a very amusing biographical notice by Dr. Maginn. The picture represents Faraday lecturing, and surrounded by his apparatus. The article begins thus : — Here you have him in his glory — not that his position was inff/orious when he stood before Melbourne, then decorated with a blue velvet travelling cap, and lounging with one leg over the chair of Canning ! — and distinctly gave that illus- trious despiser of "humbug" to understand that he had mistaken his lad. No ! but here you have him as he first MtCHAELS PENSION. 73 tiayhed upon the intelligence of mankind the condensation of the gases, or the identity of the five electricities. After a lively summary of his career, and the jocular suggestion that, as the successor of Sir Humphry Davy, Far-a-day must be near-a-knight the article continues : — The future Baronet is a very good little fellow . . . playing a fair fork over a leg of nuitton, and devoid of any reluctance to partake an old friend's third bottle. Wc know of few things more agreeal)]c than a cigar and a bowl of punch (which he mixes admiral tly) in the society of the unpretending ex- bookbinder. . . . Well, although Young got Eroderip to write a sort of defence of his master, and "Justice B " — mirahile dictu! — got Hook to print it in the JoJin BuH^ the current of public feeling could not be stopped : Regina spoke out — William E,EX, as in duty bound, followed — Melbourne apologised^and "Michael's pension, Michael's pension" is all right. In one of his note-books of this period is found the following entry : — 15 January, 1834. ^yithin the last Aveek have observed twice that a slight obscurity of the sight of my left eye has happened. It occurred on reading the letters of a book held about fourteen inches from the eye, being obscured as by a fog over a space about half an inch in diameter. This space wns a little to the right and below the axes of the eye. Looking for the effect now and other times, I cannot perceive it. I note this down that I may hereafter trace the progress of the effect if it increases or becomes more common. Happily, the trouble did not recur ; but the entry is characteristic of the habits of accuracy of the man. Loss of memorj^, unfortunately, early set in. There is 74 MICHAEL FARADAY. actually a hint of this in the tirst of his letters to Abbott (p. 7), and references to the trouble and to dizziness in the head recur perpetually in his correspondence. Whenever these brain - troubles threatened, he was compelled to drop all work and seek rest and chanc:e of scene. He often ran down to Brighton, which he thought, however, a poor place. He constructed for himself a velocipede* on which to take exercise. Tavo or three times he went to Switzerland for a longer holiday, usually accompanied by his wife and her brother, George Barnard. "Physically," says Tyndall, "Faraday was below the middle size, well set, active, and with extra- ordinar}^ animation of countenance. His head from forehead to back was so long that he had usuall}' to bespeak his hats." In 3^outh his hair was brown* curling naturally : later in life it approached to white, and he always parted it down the middle. His voice Avas pleasant, his laugh was heart}^ his manners when with young people, or when excited by success in the laboratory, were gay to boyishness. Indeed, until the end of the active period of his life he never lost the capacit}^ for boyish delight, or for unbending in fun after the stress of severe labour. '•" " It was probably in a four-\vheelef.l vclociiK.'de that l^avaday was accustomed, some thirty years ago, to woik his way up and down the steep roads near Hampstead and Highgate. This machine appears to have been of his own construction, and was worked by levers and a crank axle in the same manner as the rest of the foiir--wheeled class." — The Velocipede : its past, its present , and its future. By J. F. B. Firth. London, 18G9. CHAPTER III. SCIENTIFIC RESEARCHES : FIRST PERIOD. From first to last the original scientiiic researches ot Faraday extend over a period of forty-four years, beginning with an analysis of caustic lime, published in the Quarterly Journal of Science in 181G, and ending with his last unfinished researches of 1860 to 1862, on the possible existence of new relations betAveen magnetism and gravity and between mag- netism and light. The mere list of their titles tills several pages in the catalogue of scientific papers published by the Royal Society. For convenience of description, these forty-four years nmy be divided into three periods : the first lasting from 1816 to 1830, a period of miscellaneous and in some respects preliminary activity; the second from 1831 to the end of 1839, the period of the classical experimental researches in electricity down to the time when they were temporarily suspended by the serious state of his health ; the third from 1844, when he Avas able to resume work, down to 1860, a period which includes the completion of the experi- mental researches on electricity, the discovery of the 76 MICHAEL FARADAY. relations between light and magnetism, and that or diamagnetism. Faraday's tirst research was an analysis for Sir Humphry Daw of a specimen of caustic lime which had been sent to him by the Duchess of Montrose from Tuscany. The Qnarterhj Journal of Science, in which it appeared, was a precursor of the Proceedings of the Boyal In.^fitution, and was indeed edited bj' Professor W. F. Brande. Faraday frequent!}' wrote for it during these years, and took editorial charge ot it on more than one occasion during Brande's holidays. The paper on caustic lime was reprinted by Faraday in the yolume of his " Experimental Researches on Chemistry and Ph3-sics," prefaced by the following note : — I reprint this paper at full length ; it was the beginning of my communications to the public, and in its results very important to me. Sir Humphry Davy gave me the analysis to make as a first attempt in chemistry, at a time when my fear was greater than my confidence, and both far greater than my knowledge : at a time also when I had no thought of ever writing an original paper on science. The addition of his own comments, and the publication of the paper, encouraged me to go on making, from time to time, other slight communications, some of which ajtpear in this volume. Their transference from the Qnarferh/ into other journals increased my boldness, and now that fort}^ years have elapsed, and I can look back on what successive communications have led to, I still hope, much as their character has changed, that I have not either now or forty years ago been too bold. For the next two or three years Faraday was very closely occupied in the duties of assisting Sir Humphry Davy in his researches, and in helping to KESEARCHES BEOTNXINa 77 prepare the lectures for both Davy and Brande. Yet he found time still to work on his own account. In 1817 he had six papers and notes in the Qiiarteiiy Journal of Science, including one on the escape of gases through capillary tubes, and others on wire- gauze safety lamps and Davy's experiments on fiame. In 1818 he had eleven papers in the Journal; the most important being on the production of sound in tubes by flames, while another was on the combustion of the diamond. In 1819 he had nineteen papers in the Qiutrterly Journal, chiefly of a chemical nature. These related to boracic acid, the composition of steels, the separation of manganese from iron, and on the supposed new metal, " Sirium " or " Yestium," which he showed to be only a mixture of iron and sulphur with nickel, cobalt, and other metals. The year WW was marked in the annals of science by the discovery, by Oersted of Copenhagen, of the prime fact of electromagnetism, the deflexion which is produced upon a magnetic needle by an electric current that passes either under or over the needle. Often had it been suspected that there must be some connection between the phenomena of electricity and those of magnetism. The similarities between the attractions and repulsions caused by electrified bodies, and those due to the magnet when acting on iron, had constantly suggested the possibility that there was some real connection. But, as had been pointed out centuries before by vSt Augustine, while the rubbed amber will attract any substance if only small or light enough, being indifferent to its material, the magnet will only attract iron or compounds of iron, and is totally 78 MICHAEL FARADAY. iaoperative* on all other substances. Again, Avliile it had been noticed that in houses which had been, struck by hghtning knives, needles, and other steel objects near the path of the electric flash had become magnetised, no one had been able, b}' using the most powerful electric machines, to repeat with certainty the magnetisation of needles. In vain they had tried to magnetise knives and wires by sending sparks through them. Sometimes they showed a trace of magnetism, sometimes none. And in the cases where some slight magnetisation resulted, the polarity could not be depended upon. Van Swinden had written a whole treatise in two volumes on the analogies between electricity and magnetism, but left tlie real relation between the two more obscure than ever. After the invention, in ISOO, of the voltaic pile, which for the tirst time provided a means of generating a steady flow or current of electricity, several experi- menters, including Oersted himself, had again essayed to discover the long-suspected connection, but with- out success. Oersted was notoriously a poor experi- menter, though a man of great philosophical genius. Having in 1820 a more powerful voltaic battery in operation than previousl3^ he repeated! the operation of bringing near to the compass needle the copper wire that conveyed the current; and, laying it parallel to the needle's direction, and over or under it, found that the needle tended to turn into a direction at right " Except on nickel and cobalt, which are also para-magnetic metals. + For a graphic acoouat hy Hansteen of the circnmstances of Oersted's discovery, see Bence Jones's " Life and Letters of Fumday," vol. ii. p- 390. oersted's discoveuy. 79 angles to the line of the current, the sense of the deviation depending upon the direction of liow of the current, and also on the position of the wire as to whether it were above or below the needle. A current flowing' from south to north over the needle caused the north-pointing end of the needle to be deflected westwards. If tlie wire were vertical, so that the current flowed downwards, and a compass needle was brous^ht near the wire on the south side, therefore tending under the earth's directive influence to point northwards toward the wire, it was observed that the effect of the current flowing in the wire was to cause the north-pointing end of the needle to turn west- wards. Or, reversing the flow of current, the effect on the needle was reversed ; it now tended eastwards. All these things Oersted summed up in the phrase that " the electric conflict acts in a revolving manner " around the Avire."^ In modern phraseology the whole of the actions are explained if one can conceive that the effect of the electric How in the wire is to tend to make the north pole of a magnet revolve in one sense around the wire, whilst it also tends to make the south pole of the magnet revolve around the wire in the other sense. The nett result in most cases is that * " To the effect which takes place in this conductor [or uniting wire] and in the surrounding space, we shall give the name of the coiijiict of electricity.'" .... "From the preceding facts wo ma}'' likewise collect that this con- flict performs circles ; for without this condition, it seems impossible that the one part of the uniting wire, when placed helow the magnetic pole, should drive it towards the east, and when placed above it towards the west ; for it is the nature uf a circle that the motions in opposite parts should have an opposite direction." — H. C. Oeksted, Ann. of I'hxL, Oct., 1820, pp. 273—276. -SO MICHAEL FARADAY. the magnetic needle tends to set itself square across the line of the current. Oersted himself was not too clear in his explanations, and seems, in his later papers, to have L^st sic^ht of the circular motion amidst repulsions and attractions. This discovery, which showed Avhat was the freometrieal relation between the macmet and the current, also showed why the earlier attempts had failed. It was requisite that the electricity should be in a state of steady tioAv ; neither at rest as in the experiments with electric charges, nor yet in capricious or oscillatory rush as in those with spark-discharges. Farada}', adverting a quarter of a century later to Oersted's discovery, said : " It burst open the gates of a domain in science, dark till then, and tilled it with a flood of light." The very day that Oersted's memoir was pub- lished in England, Davy brought a copy down into the laboratory of the Royal Institution, and he and Faraday at once set to work to repeat the experi- ments and verify the facts. It is a matter of history how, on the publication of Oersted's discovery, Ampere leaped forward to creneralise on electromagnetic actions, and discovered the mutual actions that may exist between two currents, or rather between tw^o conducting wires that carrj' currents. They are found to experience mutual mechanical forces urging them into parallel prox- imity. Biot and Laplace added to these investiga- tions, as also did Arago. Davy discovered that the naked copper wire, while carrying a current, could attract iron filings to itself — not end-ways in adherent o A PARADOXICAL PHENOMENON. 81 tufts, as the pole of a magnet does, but laterally, each filing or chainlet of tilings tending to set itself tangentially at right angles to the axis of the wire. This curious right-angled relation between electric flow and magnetic force came as a complete paradox or puzzle to the scientific world. It had taken centuries to throAv off' the strange unmechanical ideas of force which had dominated the older astronomy. The epicyclic motions of the planets postulated by the Ptolemaic system were in no way to be accounted for upon mechanical principles. Kepler's laAvs of planetary motion were merely empirical, embodying the results of observation, until Newti^n's discovery of the laws of circular motion and of the principle of universal gravitation placed the planetary theory on a rational basis. NcAvton's laws required that forces should act in straight lines, and that to every action there should be an equal and opposite reaction. If A attracted b, then b attracted A with an equal force, and the mutual force must be in tlie line drawn from A to B. The discovery by Oersted that the magnet pole was urged by the electric wire in a direction transverse to the line joining them, appeared at first sight to contravene the ideas of force so thoroughly established by Newton. How could this transver- sality be explained ? Some sought to explain the effect by considering the conducting wire to operate as if made up of a number of short magnets set transversely across the wire, all their north poles being set towards the right, and all their south poles towards the left. Ampere took the alternative view G S'2 MICHAEL FARADAY. that the iiiagiiot might bo rcgardod as oijuivaloiit to a number of electric currents circuhitiug transversely around the core as an axis. In neither case was the exphxnation complete. Fai-aday's scientitic activities in the year ]S2() Avere very marked. New researches on steel had been going on for soine months. It had been hoped that by alloying iron with some other metals, such as silver, platinum, or nickel, a non-rusting alloy might be found. This idea took its rise from the erroneous notion that meteoric iron, which is ri(;hly alloyed with nickel, does not rust. Faraday found nickel steel to be more readily oxidised, not less, than ordinary steel. The platinum steel was also a failure. Silver steoi was of more interest, though it Avas found imjiossible to incorporate in the alloy more than a small percentage of silver. Nevertheless, sih^er steel was used for some time Ly a Sheffield firm for manufacture of fenders. The alloys of iron with platinum, iridium, and rhodium were also of no ng and chatty abstract of his researches on the alloys of steel. They appear to have originated in son:ie anah-ses ot' wootz or Indian steel, a material which, when etched Avith acid, shows a beautifully damascened or reti- culated surface. This effect Faraday never found with pure steel, biu imitated it successfuUv with a steel aUoyed with " the n:ietal of alunhne," an element which do"\\'n to that time had not been isolated. He then describes the rhodium, silver, and nickel steels, and mentions incidentally how he has been surprised to discover that he can volatilise silver, and that he cannot reduce the metal titanium. He is doubtfid whether this metal '' ever has been reduced at all in the pure state." [It can now be readily reduced either in the electric arc m' by the use of metallic aluminimn.] He winds up the letter with the Avords : '• Pray pity us that, after two years' experin:ients, we have got no further : but I am sure, if you knew the labour of the experiments, you would applaud us for our perseverance at least." In 1821, the xear of his marriage, came the tirst of the important scientitic discoveries which brought him international fame. This was the discovert' of the electromagnetic rotations. It appears that Oersted's brilliant flash of insight that the ■ electric conflict acts in a revolving manner " upon the pole of the neighbouring compass needle had been lost sight of in the discussions which followed, and to Avhich allusion has been made above. All the world was thmking about attractions and repulsions. Two men, 84 MICHAEL FARADAY. however, seem to have gone a little further in their ideas. Dr. WoUaston had stiggested that there onght to be a tendency, when a magnet pole was presented towards a straight conducting wire carrying a current, for that contlucting wire to reyolve around its own axis. This etiect — though in recent years it has been observed by Mr. George Gore — he unsuccessfully tried to observe bv experiments. He came in April, Ks21. to the laboratory of the Royal Institution to make an experiment, but Avitbout result. Faraday, at the request of his friend Phillips, who was editor of the Anutd^ of FIdlosopJnj, wrote for that magazine in Jidy. August, and September a historical sketch oi electromagnetism down to date. This was one of the very few of Faraday's writings that was anonymous. It was simpl}' signed " ^[." This is in vol. iii. p. 107. On p. 117 the editor says: "To the historical sketch o( electromagnetism with which I have been favoured bv my anonymous correspondent. I shall add a sketch of the discoveries that have been made by ^Ir. Faraday of the Eoyal Institution." In the cotn-se of this Avork Faraday repeatetl for his own satisfaction almost all the experiments that he described. This led him to discover that a wire, included in the circuit, but mounted so as to hang Avith its lower end in a pool of quicksilver, coidd rotate around the pole of a magnet : and conversely that if the wire were tixed and the pole of the magnet free to move, the latter would rotate around the former. " I did not realise." he wrote, " Dr. AVollaston's expectation of the rotation of the electromagnetic wire around its axis." As was so often his custom, he had no sooner finished the LETTER TO DE LA lUVE. S5 research for publication than he dashed off a brief smnmary of it in a letter to one of his friends. On this occasion it was Professor G. de la Rive, of Geneva, who was the recipient of his confidences, On September 12 he wrote : — I am much flattered and encouraged to go on by your good opinion of what httle things I have been able to do in science, and especially as regards the chlorides of carbon. You partly reproach us here with not sufficiently esteeming Amperes experiments on electromagnetism. Allow me to extenuate your oiiinion a little on this point. ^Yith regard to the experiments, I hope and trust that due weight is allowed to them ; but these you know are few, and theory makes up the great part of what M. Ani}>ere has published, and theory in a great many points unsupported by experiments when they ought to have been adduced. At the same time, ^L Ampere's ex]")eriments are excellent, and his theory ingenious ; and, for myself, I had thought very little about it Ijefore your letter came, simply because, heing naturally sceptical on philosophical theories, I thought there was a great want of experimental evidence. Since then, however, I have engaged on the subject, and have a paper in our "Institution Journal," which will iippear in a week or two, and that will, as it contains experi- ment, be immediately applied by M. Ampere in support of his theory, much more decidedly than it is Ly myself. I intend to enclose a copy of it to you with the other, and only want the means of sending it. I find all the usual attractions and repulsions of the magnetic needle by the conjunctive wire are decep)tions, the motions being not attractions or repulsions, nor the result of any atti'active or repulsive forces, but the result of a force in the wire, which instead of bringing the jtole of the needle nearer to, or further from the wire, endeavours to make it move round it in a never ending circle and motion whilst the 86 MICHAEL FAKADAV. battery remains in action. I have succeeded not only in showing the existence of this motion theoretically, but experi- mentally, aud have been able to make the wire revolve round a magnetic pole, or a magnetic pole round the wire, at pleasure. The law of revolution, and to which all the other motions of the needle and wire are reducible, is simple and beautiful. Conceive a portion of connecting wire north and south, the north end being attached to the positive pole of a battery, the south to the negative. A north magnetic pole would then pass round it continually in the apparent direction of the sun, from east to west above, from went to east V^elow. Reverse the connections with the battery, and the motion of the pole is rc-verse'] ; or if the south pole be made to revolve, the motions will be in the opposite directions, as with the north pole. If the wire be made to revolve round the pole, the motions are according to those mentioned. In the apparatus I used there were but two plates, and the directions of the motions were of course* the revenje of those with a battery of several pairs of plates, and which are given above. Xow I Ixave been able, experimentally, to trace this motion into its various forms as exhibited Vjy Ampere's, Xelice's, roduced by other agencies ; and therefore, until the presence of electrical currents be proved in the magnet by other than * This hi an hrrOT (hxc to hasta in writintr. LEAVES FROM THE XOTE-BOOK. 87 ma^^netical effects, I shall remain in doubt about Ampere's tlieor)^ L Wishing you all health and happiness, and waiting for news from you, I am, my dear Sir, your very obliged and grateful M. Faraday, The reference at the be^^inninc^ ot this letter to the chlorides of carbon has to do with his discovery communicated to the Royal Society. Later in the year, a joint paper on another compound of carbon and chlorine, by himself and his friend Eichard Phillips, was sent in. Both were ])rinted together in i\\Q Fhilosopliical Ti-an.^artions of 1821. The folloAving is an extract from Faraday's labora- tory book relating to the discovery. The accoimt is incomplete, a leaf having been torn out :— 1.^21, Sept. 3. The effort of the wire is always to pnss off at a riglit angle from the pole, indeed to go in a circle round it, so when either pole was brought up to the wire perpendicular to it and tu tlie radius of the circle it described, there was neither attraction nor repulsion, but the moment the pole varied in the slightest manner either in or out, the wire moved one way or the other. The poles of the magnet act on the bent wire in all positions and not in the direction on/// of any axis of the magnet, so that the current can hardly be cylindrical or arranged round the axis of a cylinder? From the motion above a north magnet pole in the centre of one of the circles should make the wire continually tarn round. Arranged amagnet needle in a glass tube with mercury about it, and l.iy a cork, water, itc, supported a connecting Avire so that the upjier end should go into the silver cui) and its mercur}^ and the lower move in a channel of mercury round 88 MICHAEL FARADAV. the pole of the needle. The battery arranged with the -wire as before. In this -way got the revolution of the "wire round the pole of the magnet. The dkection was as follow, looking from above down : — (Facmmile of Original Sketch.) Very satisfactory, but make more sensible apparatus- Tuesday. Se])t. 4. Apparatus for revolution of wire and magnet. A deep basin with bit of Avax at bottom and then tilled with mercury. A magnet stuck upright in was so that pole just above the surface of mercury. Then piece of wire floated by cork at lower end dipping into mere- and above into silver cup as before :— •■'W Fig. 3. (Fac^^imile uf Ukigixal Sketch.) The research on the electroinao-netic rotations, which was published in the Qnt/rterb/ Journal of Science for October, 1821 (and reprinted in the second Tohtme of the '^ Experimental Researches in Elec- tricity '% was the occasion of a very serious misunder- standing with Dr. Wollaston and his friends, which at one time threatened to cause Earaday's exchision SCENES IN THE LABORATORY. 89 from the RoA-al Society. Faraday's prompt and frank action in appealing to iJr. AVollaston saved him in a very unpleasant crisis : and the latter came three or four times to the laboratory to witness the experi- ments. On Christmas Day of the same year, Faraday succeeded in making a wire through which an electric current is passing move under the influence of the earth's magnetism alone. His brother-in-law, George Barnard, who was in the laboratory at the time, wrote: — "All at once he exclaimed, 'Do you see, do you see, do you see, George ? ' as the wire began to revolve. One end I recollect was in the cup of quick- silver, the other attached above to the centre. I shall never forget the entliusiasm expressed in his face and the sj^arkling in his eyes ! " In 1S22 little was added to Faraday's scientific work. He had a joint paper Avith Stodart on steel before the Royal Society, and in the Quarterly Journal two short chemical papers and four on electromagnetical motions and magnetism. He had long kept a commonplace book in which he entered notes and queries as well as extracts from books and journals ; but this year he began a fresh manuscript volume, into which he transferred many of the queries and suggestions of his own originating. This volume he called "Chemical Notes, Hints, Suggestions, and Objects of Pursuit." It contains many of the germs of his own future discoveries, as the following examples show : — Convert magneti.sm into electricity. Do pith baits diverge Ijy disturbance of electricities in consequence of induction or not? 90 MICHAEL FAKADAY. General effects ot compression, either in condensing gases, 01" producing solutions, or even giving combinations at low tem[)eratures. Light through gold leaf on to zinc or most uxidable metals, these being poles — or on magnetic bars. Transparency of metals. Suii's light through gold leaf. Two gold leaves made poles— light passed through one to the other. Whenever any query found an answer, he drew his pen through it and added the date. In front of the book — probably at some later time — he wrote these Avords : — I already owe much to these notes, and think such a collection "\vorth the making by every scientific man. 1 am sure none "would think the trouble lust after a year's experience. A striking:;' example had already occurred of similar suggestive notes in the optical queries of Sir Isaac Xewton. In another manuscript notebook occur the follow- ing entries under date of September 10, 1821 : — •2 similar poles though they repell at most distances attract at very small distances and adhere. Query wh)- Could not magnetise a plate of steel so as to resemble tlat spiral. Either the magnetism would be very ^\eak and irregular or there would be none at all. These are interesting as showing how Faraday was educating himself by continual experiment. The explanation of each of these paradoxes has long passed into the commonplace of physics ; but they would still puzzle many wdio have learned their science bookishl^' at second-hand. AN UNSUCCESSFUL EXPERIMENT. 91 It will be noted that amongst the entries cited above there are two of absolutely capital importance, one foreshadowing the great discovery of magneto- electric induction, the other indicating how the existence of electro-optical relations was shaping itself as a possibility in Faraday's mind. An entry in his laboratory book of September 10 is of great interest : — Polarised a ray of lamp light by reflection, and endeavoured to ascertain whether any depolarising^ action [is] exerted on it by water placed between the poles of a voltaic battery in a glass cistern ; one WoUaston's trough used ; the fluids decomposed were pure water, weak solution of .sulphate of soda, and strong sulphuric acid : none of them had any effect on the polarised light, either when out of or in the voltaic circuit, so that no i)articular arrangement of particles could be ascertained in this way. It may be added that no such optical effect of electrolytic conduction as that here looked for has yet been discovered. The experiment, unsuccessful at that da}^ remains still an unsuccessful one. A singular interest attaches to it, however, and it was repeated several times by Faraday in subsequent years, in hope of some results. In 1S28 Faraday read two papers to the Royal Society, one on Liquid Chlorine, the other on the Condensation of several Gases into Liquids. No sooner was the work completed than he dashed off a letter to \)e la Rive to tell him what he had accom- plished. Under date March 24, 1828, he writes : — I have been at work lately, and ohtained results which I hope you will approve of. I have been interrupted twice in 02 MICHAEL FARADAY. the course of experiments Viy explosions, both in the course of ei^ht days— one burnt my eyes, the other cut them ; but fortunately escaped with slight injury only in both cases, and am now nearly well. Daring the winter I took the oppi>rtunity of examining the liyJrate of chlorine, and analysing it : the results, which are not very important, will appear in the next number of the Qiuirttrh/ Journal, over which I have no intiuence. Sir H. Davy, on seeing my paper, suggested to me to work with it under pressure, and see what would ha]>pen by heat, ttc. Accordingly I enclosed it in a glass tube hermetically sealed, heated it, obtained a change in the substance, and a separation into two different fluids ; and upon farther examina- tion I found that the chlorine and water had separated from each other, and the chlorine gas, not being able to escape, had condensed into the liijuid form. To prove that it contained no water, I dried some chlorine gas, introduced it into a long tube, condensed it, and then cooled the tube, and again obtained fluid chlorine. Hence what is called chlorine gas is the vapour of a fluid I expect to be able to reduce many other gases to the liquid form, and promise myself the pleasure of writing you abnut them. I hope you "^ill honour me with a letter soon. I am, dear Sir, very faithfully, your obedient servant, M. Faraday. The work of liquefying the gases had been taken up by Farada}' during his hours of liberty from other duties. It was probably his characteristic dislike to '^ doubtful knowdedge " -which prompted him to re- examine a substance "which had at one time been regarded as chlorine in a solid state, but Avhich DaYy hr ISIO had demonstrated to be a hydrate of that element. The tirst Avork was, as narrated aboYe, to make a new analysis of the supposed substance. This analYsis, duh' written out, was submitted to Sir CHLORINE LIQUEFIED. 93 Humphry, who, without statmg precisely what results he anticipated might follow, suggested heating the hyd.rate under pressure in a hermetically sealed glass tube. This Faraday did. When so heated, the tube filled with a yellow atmosphere, and on cooling was found to contain two liquids, one limpid and colour- less like water, the other of an oily appearance. Concerning this research a curious story is told in the life of Davy. Dr. Paris, Davy's friend and biographer, happened to visit the laboratory while Faraday was at work on these tubes. Seeing the oily liquid, he ventured to rally the young assistant upon his care- lessness in employing greasy tubes. Later in the day, Faraday, on filing oft' the end of the tube, was startled by finding the contents suddenly to explode ; the oily matter completely disappearing. He speedily ascertained the cause. The gas, liberated from com- bination with Avater by heat, had under the pressure of its own evolution liquehed itself, only to re-expand with violence when the tube was opened. Early the next day Dr. Paris received the following laconic note : — Dear Sie,— The oil you noticed yesterday turns out to be liquid ciik)rine. Yours faithfully, M. Faraday. Later he adopted a compressing syringe to condense the gas, and again succeeded in liquefying it. DaA^y, who added a characteristic note to Faraday's published paper, immediately applied the same method of liquefaction by its own pressure to hydrochloric acid 94 MICHAEL FARADAY. o;;is ; and Faraday reduced a number of other gases b}^ the same means. These researches were not "with- out danger. In the prehmmary experiments an ex- plosion of one of the tubes drove thirteen fragments of glass into Faraday's eye. At the end of the year he drew up a historical statement on the liquefaction of gases, which was published in the Quarterb/ Journal for January, 1824. A further statement by him was published in the FJ/ ilosopJiicul Magaziiif for 1S3G : and in Fs4-I- his further researches on the lique- faction of gases were published in the P]tih)sop]tical Tr(rnsaction><. In 1824- Faraday ao-ain brought to the Eoyal Society a chemical discovery of first importance. The paper was on some new compounds of carbon and hydrogen, and on certain other products obtained during decomposition of oil by heat. From condensed oil-gas, so obtained, Faraday succeeded in separating the liquid kno'\\Ti as benzin or benzol, or, as he named it at the time, bicarburet of hydros'en. It has since its discover}' formed the basis of several great chemical industries, and is manufactured in vast quantities. Prior to the reading of this paper he had, as we have already related, been elected a Fellow of the Royal Society, an honour to which he had for some 3'ears aspired, and which stood alone in his regard above the scientific honours of later years. In this year he tried, amongst his unsuccessful experiments, two of singular interest. One was an attempt to find Avhether two crystals (such as nitre) exercised upon one another any polar attractions like those ot two lodestones. He suspended them by ItESEARCH ON OPTICAL GLASS. 95 fibres of cocoon silk, and, finding this niaterial not delicate enough, by spider-lines. The other was an attempt to discoAxr magneto-electricity. For various reasons he concluded that the approximation of the pole of a powerful magnet to a conductor carrying a current would have the effect of diminishing the amount of that current. He placed magnets within a copper wire helix, and observed Avith a galvanometer whether the current sent through the circuit of the helix by a given battery was less when the magnet was absent. The result was negative. In this year also began the laborious researches on optical glass, which though in themselves leading to no immediate success of counnercial value, nevertheless furnished Faraday Avith the material essential at the time for the making of the most momentous of all his discoveries. A committee had been appointed by the President and Coimcil of the Royal Society for the improvement of glass for optical purposes, and Faraday was amongst those chosen to act upon it. In 1825 the Royal Society Committee delegated the investigation of optical glass to a sub-committee of three, Herschel (afterAvards Sir John), Dollond (the optician), and Faraday. The chemical part, in- cluding the experiniental n:ianufacture, Avas entrusted to Faraday. Dollond Avas to Avork the glass and test its cpialities from the instrument maker's point of view, Avhilst Herschel Avas to examine its refraction, dispersion, and other physical properties. This sub- committee Avorked for nearly live years, though by the removal of Herschel from England its number Avas 96 ^[ICHAEL FARAPAV. reduced to uxo. In 1827 the work became more arduous. Faraday thus writes : — The President and Council of the Royal Society applied to the President and Managers of the Pioyal Institution for leave to erect on their juemises an experimental room "with a furnace, for the purpose of continuing the investigation on the manufacture of optical gla-s. They were guided in this hy the desire which the Royal Institution has always evinced to assist in the advancement of science ; and the readiness with which the application was granted shewed that no mistaken notion had been formed in this respect. Asa member of both bodies. I felt much anxiety that the investigation should he successful. A room and furnaces were built at the Royal Institution in September, 18i?7, and an assistant was engaged, Sergeant Anderson, of the Royal Artillery. He came on the 3rd of December. Anderson, who was thus made assistant to P'araday, remained in that capacity till his death in 1866. He was a juost devoted servant. In a footnote to the ■■ Experimental Researches " {\o\. iii. p. 3) Faraday in 1845 wrote of him : — I cannot resist the occasion that is thus- offered me of mentioning the name of ^Ir. Anderson, who came to nie as an assistant in the glass experiments, and has remained ever since in the laboratory uf the Royal Institution. He assisted uie in all the researches into which I have entered since that time ; and to his care, steadiness, exactitude, and faithfulness in tlie performance of all that has been committed to his charge. I am much indebted. — M. F Tyndall, who hnd a great admiration for Anderson, declared that his njerits as an assistant might be summed up in one phrase — blind obedience. The stor}' is told of him by Benjamin Abbott : — andekson's obedience. 97 Sergeant Anderson . . . was chosen simply because of the habits of strict obedience his military training had given him. His duty was to keep the furnaces always at the same heat, and the water in the ashpit always at the same level. In the evening he Avas released, but one night Faraday forgot to tell Anderson he could go home, and early next morning he found his faithful servant still stoking the glowing furnace, as he had been doing all night long. The research on optical glass "was viewed askance by several parties. The expenditure of money which it involved was one of the " charges " hurled against the Council of the Royal Society by Sir James South in 1830. Nevertheless it Avas deemed sufficiently important to receive powerful support, as the follow- ing letter shows : — Admiralty, 20 Dec, 1827. SiE, I hereby request, on behalf of the Board of Longitude, that you will continue, in the furnace built at the Royal Institution, the experiments on glass, directed by the joint Committee of the Royal Society and the Board of Longitude' and already sanctioned by the Treasury and the Board of Excise. I am, Sir, > Your obedient servant, Thomas Young, M.D., Michael Faraday, Esq., Sec. Bd. Long. Royal Institution. In February, 1825, Faraday's duties toAvards the Royal Institution were someAvhat modified. Hitherto he had been nominally a mere assistant to Davy and Brande, though he had occasionally undertaken lectures for the latter. Now, on Davy's recommenda- tion, he was, as we have seen, appointed by the H 98 MICHAEL FARADAY. managers Director of the Laboratory under the super- intendence of the Professor of Chemistry. He was reUeved, " because of his occupation in research," Irom his duty as chemical assistant at the lectures. The research on optical glass "was not concluded till 1S2P. when its results were communicated to the Royal Society in the Bal^erian lecture of that year — a memoir so long that it is said three sittings Avere occupied in its delivery. It is printed ni e.'ienso in the P]iilo--«jp]ilriil Trii iisocfioiis of 1880. It opens as f(.)ll[)ws : — ^\']lL'll the liliilo^-ojilier dc^irei^ td apply glass in the coii- -stiuction of iierfcct instruments, and especially' the achroniatiL- telescope, its manufacture is found lialile to imperfections su important and so ditiicult to avoid, that science is frequently stopped in her prog^vess by them — a fact fully proved by the circumstance that Mr. l)ol]ond, one of our first opticians, has not been able to obtain a disc of tiint ylass 4^ inches in diameter, tit for a telescope, within the last five years ; or a similar disc, of 5 inches, within the last ten years. This led to the appointment by Sir H. Davy of the Eoyal Society Committee, and the Government removed the excise restrictions, and xuidertook to bear all the ex])enses as long as the investig-atiou otfered a reasonable hope of success. The experiments were begun at the Falcon Glass Works, three miles from the Eoyal Institution, and continued there in 1825, 1826, and to Sept., Ls27, when a room was built at the Institution. At tirst the inijuiry was pursued principally as related to tiint and crown glass ; but in September, 1828, it was directed exclusively to the preparation and perfection of peculiar heavy and fusible glasses, from which time continued progress has been made. In 1830 the experiments on glass-making were stopped.. In 1S31 the Committee for the Improvement of GLASH-MAKINfi LAID ASIDE. 99 Glass for Optical Purposes reported to the Royal Society Council that the telescope made with Mr. P\araday's glass had been examined by Captain Kater and Mr. Pond. " It bears as great a power as can reasonably be expected, and is very achromatic. The Committee therefore recommend that Mr. Faraday be requested to make a perfect piece of glass of the largest size that his present apparatus Avill admit, and also to teach some person to manufacture the glass for general sale." In answer to this Faraday sent the following letter to Dr. Roget, Sec. R.S. :— [M. Fan(24 Arago had observed that a tine magnetic compass constructed for him by Gainbey, having the needle suspended in a cell, the base of which Avas a plate of piu'e copper, Avas thereby damped in its oscillations, and instead of making two or three hundred vibrations before it came to rest, as would be the case in the open air, executed only three or four of rapidly decreasing amplitude."^ In vain did Dumas at the request of Arago analyse the copper, in the supposition that iron might be present. Inquiry compelled the conclusion that some other explanation must be sought. And, reasoning irom the apparent action of stationary copper in bringing a moving magnetic needle to rest, he conjectured that a moving mass of copper might produce motion in a stationary magnetic needle. Accordingly he set into revolution, beneath a compass needle, a flat disc of copper, and found that, even when a sheet of card or glass Avas interposed to cut off all air-currents, the needle tended to follow the moA^ing copper disc, turning as if dragged ^' Compare Dumas, " Kloge Histoiique de Michel Faniday," p. xxxiii., who gives the above statement. Arago's own account to the Acadimk differs slightly. A PUZZLING EXPERIMENT. 107 by some invisible influence. Tr) the suggestion that mere rotation conferred upon copper a sort of temporary magnetism Arago listened with some impatience. All theories proposed to account for the phenomenon he discredited, even though emanating from the great mathematician Poisson. He held his j udgment in absolute suspense. Babbage and Herschel measured the amount of retarding force exerted on the needle by different materials, and found the most eftective to be silver and copper (which are the two best conductors of electricity), after them gold and zinc, whilst lead, mercury, and bismuth were inferior in power. The next year the same experimenters announced the successful inversion of Arago's experiment ; for by spinning the magnet underneath a pivoted copper disc they caused the latter to rotate briskly. They also made the notable observation that if slits are cut radially in the copper disc they diminish its tendency to be dragged by the spinning magnet. Sturgeon showed that the damp- ing effect of a moving copper disc was diminished by the presence of a second magnet pole of contrary kind placed beside the first. All these things were most suggestive of the real explanation. It clearly had something to do with the electric conductivity of the metal disc, and therefore with electric currents. Sturgeon five years later came very near to the explanation : after repeating the experiments he con- cluded that the effect was an electric disturbance in the copper disc, " a kind of reaction to that which takes place in electromagnetism." Faraday knew of all the discussions which had 108 MICHAEL FAUADAV. arisen respecting Arago's rotations They may have been the cause of his unsuccessful attempts of 1824 and 1825. In April, 1828, for the fourth time he tried to discover the currents which he was convinced must be producible by the magnet, and for the fourth time without result. The cause of failure A^^as that both magnet and coil were at rest. Fig. 4. The summer of 1831 witnessed him for the fifth time making the attaclv on the problem thus per- sistently before him. In his laboratory note-book he heads the research " Experiments on the production of electricity from magnetism." The following ex- cellent summary of the laboratory notes is taken from Bence Jones's " Life and Letters " : — I have had an iron ring made (soft iron), iron round and gths of an inch thick, and ring six inches in external diameter. Wound many coils of copper round, one half of the coils being separated by twine and calico ; there were three lengths of SUCCESS IN sioriT. 109 wire, each about twenty-four feet long, and they could be con- nected as one length, or used as separate lengths. By trials with a trough each was insulated from the other. Will call this side of the ring a. On the other side, but separated by an interval, was wound wire in two pieces, together amounting to about sixty feet in length, the direction being as with the former coils. This side call b. ^ Charged a battery of ten pairs of i)lates four inches square. Made the coil on e side one coil, and connected its extremities by a copper wire passing to a distance, and just over a magnetic needle (three feet from wire ring), then connected the ends of one of the pieces on a side with battery : immediately a sensible effect on needle. It oscillated and settled at last in original position. On breaking connection of a side with battery, again a disturbance of the needle. In the seventeenth paragraph, written on the 30th ot August, he says, " May not these transient efi'ects be connected with causes of difierence betAveen power of metals at rest and in motion in Arago's experiments?" After this he prepared fresh apparatus. As was his manner, he wrote off to one of his friends a letter tehing what he was at work upon. On this occasion the recipient of his confidences was his friend PhilHps : — [Michael Faraday to Richard Phillips.'] Royal Institution. My dear Phillips, Sept. 23, 1831. I write now, though it may be some time before I send my letter, but that is of no great consequence. I received * This ring Faraday ia represented as holding in his hand in the heautiful marble statue by Foley which stands in the Entrance HaU of the Royal Institution. The ring itself is still preserved at the Royal Institution amongst the Faraday relics. The accompanying cut (Fig. 4) is facsimiled from Faraday's own sketch in his laboratory note -book. 110 MICHAEL FARADAY. your letter to Dr. Reid and read it on the coach going to Hastings, where I have been i)assing a few weeks, and I fancy n)y fellow passengers thought 1 had got something very droll in hand ; they sometimes started at my sudden bursts, especially when I had the moment before been very grave and serious amongst the proportions. As you say in the letter there are some new facts and they are always of value ; otherwise I should have thought you had taken more trouble than the matter deserved. Your quotation from ]joyIe has nevertheless gieat force in it. I shall send with this a little thing in your own way " On the Alleged decline of science in England." It is written by Dr. ^foU of Utrecht, whose name may be mentioned in conversa- tion though it is not printed in the pamphlet. I understand the view taken by Moll is not at all agreeable to some. "I do not know what business Moll had tointerfere with our scientific disputes " is however the strongest observation I have heard of in reply. I do not think I thanked you for your last Pharmacopoeia- I do so now very heartily. I shall detain this letter a few days that I may send a coui)le of my papers [i.e. a paper and appendix) with it, for though not chemical I think you will like to have them. I am busy just now again on Electro-Magnetism, and think I have got hold of a good thing, but can't say; it may be a weed instead of a fish that after all my labour I may at last pull up. I think I know why metals are magnetic when in motion though not (generally) when at rest. We think about you all very much at times, and talk over affairs of Nelson Square, but I think we dwell more upon the illnesses and nursings and upon the sudden calls and chats rather than the regular parties. Pray remember us both to Mrs. Phillips and the damsils — I hope the word is not too familiar. I am Dear Phillips, Most Truly Yours, P. Phillips, Esq., M. Faraday. &c., &c., iJcc. TEN DAYS OF SPLENDID WORK. Ill September 24 was the third day of his experiments. Ho began (paragraph 21) by trying to find the eh'oct of one helix of wire, carrying the vohaic current of ten pairs of pkites, upon another wire connected with a galvanometer. " No induction sensible." Longer and different metallic helices (paragraph 22) showed no effect ; so he gave up those experiments for that day, and tried the effects of bar magnets in- stead of the ring magnet he had used . {FAcrsiMiLE OF Okigin'al Sketch.) magneto-electric machines, that is to say, primitive kinds of dynamos. Having in his mind the pheno- menon discovered by Arago, and the experiments of Babbasre and Herschel on the so-called mao-netism of rotation, he followed up the idea that these effects might be due to induced currents eddying round in the copper disc. No sooner had he obtained electricity from magnets than he attempted to make Arago's experiment a new source of electricity, and, as he himself says, " did not despair " " of being able to construct a new electrical machine." 122 MICHAEL FARADAY. The " new electrical machine " was an exceedingly simple contrivance. A disc of copper, twelve inches in diameter (Fig. 6), and about one-tifth of an inch in thickness, fixed upon a brass axle, was mounted in frames, so as to allow of revolution, its edge being at the same time introduced between the magnetic poles of a large compound permanent magnet, the poles being about half an inch apart. "^^ The magnet first used was the historical magnet of Gfjwin Knight. The edge of the plate was well amalgamated, for the purpose of obtaining a good but movable contact, and a part round the axle was also prepared in a similar manner. Conducting strips of copper and lead, to serve as electric collectors, were prepared, so as to be placed in contact with the edge of the copper disc ; one of these was held by hand to touch the edge of the disc between the magnet poles. The wires from a galvanometer were connected, the one to the collect- ing-strip, the other to the brass axle ; then on revolv- ing the disc a deflexion of the galvanometer was obtained, which was reversed in direction when the direction of the rotation Avas reversed. " Here, there- fore, was demonstrated the production of a permanent current of electricity by ordinary magnets." These effects were also obtained from the poles of electro- magnets, and from copper helices without iron cores. Several other forms of magneto-electric machines were tried by Faraday. i> til 'Experimental Researches,'* i. 25, art. 85, This copper disc is still preserved at the Royal Institution. It was shown in action by the author of this work, at a lecture at the Koyal Institution delivered April 11th, 1891. Fig. 6 is reproduced in facsimile from Faraday's laboratory note-book. NEW FORMS OV APPARATUS. 123 In onc,"^' a liat ring of twelve inches' external diameter, and one inch broad, was cut from a thick copper plate, and mounted to revolve between the poles of the magnet, two conductors being applied to make rubbmg contact at the inner and outer edge at the part which passed between the magnetic poles. In another,t a disc of copper, one-fifth of an inch thick and only fi inch in diameter (Fig. 7), was amalga- mated at the edge, and mounted on a copper axle. A square piece of sheet metal had a circular hole cut in it, into Avhich the disc fitted loosely : a little mercury completed connnunication between the disc and its surrounding ring. The latter was connected by wire to a o-alvanometer ; the other wire beine* connected from the instrument to the end of tlie axle. Upon rotating the disc in a horizontal plane, currents were obtained, though the earth was the only magnet employed. Faraday also proposed a multiple machinej having several discs, metallically connected alternately at the * "Experinirntal pLesearchcs," i. art. 13-3. t Jb., art. 15,3. + lb., ait. lo 124 MICHAEL FARADAY. edges and centres by means of mercury, which were then to be revolved alternately in opposite directions, In another apparatus,* a copper cylinder (Fig. 8), closed at one extremity, was put over a magnet, one half of which it enclosed like a cap, and to which it was attached without making metalhc contact. The arrangement was then floated upright in a narrow jar Fig. 8. of mercury, so that the lower edge of the copper cap touched the fluid. On rotating the magnet and its attached cap, a current was sent through wires from the mercury to the top of the copper cap. In another apparatus, t still preserved at the Royal Institution, a cylindrical bar magnet, half immersed in mercury, was made to rotate, and generated a current, its own metal serving as a conductor. In another form,:[: the cylindrical magnet was rotated horizontally about its own axis, and was found to generate currents which * lb,, art. 219. t "Experimental Researches," i. art. 220. X lb., art. 222. AN EARTH-INDUCTOR. 125 flowed from the middle to the ends, or vice versa, accordmg to the rotation. The description of these new electrical machines is concluded with the follow- ing pregnant words ; — I have rather, however, been desirou-s of discovering new facts and relations dependent on magneto-electric induction, than of exalting the force of those already obtained ; being assured that the latter would find their full development hereafter. Fig. 9. In yet another naachine (Fig. 9), constructed by Faraday some time later * a simple rectangle of copper wire IV, attached to a frame, was rotated about a horizontal axis placed east and west, and generated alternate currents, which coidd be collected by a simple comnuitator c. Within a few months machines on the principle of magneto-induction had been devised by Dal Negro, and by Pixii. In the latter's apparatus a steel horse- shoe magnet, with its poles upwards, was caused to rotate about a vertical shaft, inducing alternating currents in a pair of bobbins fixed above it, and '^ lb., iii. art 3192. 126 MICHAEL fai:a]>av. provided with a horseshoe core of soft iron. Later, in 1832, Pixii produced, at the suggestion of Ampere,^ a second machine, provided with mercury cup con- nections to rectify the alternations of the current. One of these machines was shown at the British Association meeting at Oxford in the same year (p. 64). The idea developed in the third part of this research was intensely original and suggestive. Fara- day's own statement is as follows: — Whilst the wire i.s subject to either volta-electric or magneto- electric induction, it appears to be in a peculiar state ; for it resists the formation ot an electrical current in it, whereas, if left in its common condition, such a current would be produced ; and when left uninfluenced it has the power of originating a current, a power which the wire does not possess under common circumstances. This electrical condition of matter has not hitherto l»een recognised, but it probably exerts a very im- p>ortant influence in many, if not most, of the phenomena produced by currents of electricity. For reasons which will immediately appear, I have, after advising with several learned friends, ventured to designate it as the electrotoiiic state. This peculiar condition shows no known electrical effects whilst it continues ; nor have I yet been able to discover any peculiar powers exerted or properties possessed by matter whilst retained in this state. This state is altogether the effect of the induction exerted, and ceases as soon as the inductive force is removed The state appears to be instantly assumed, requiring hardly a sensible portion of time for that [)urpose In all those cases where the helices or wires are advanced towards or taken from the magnet, the direct or inverted current of * "Ann. Chim. Phys.," U. 76, 1832. THE ELECTKOTONKJ STATE. 127 induced electricity continues for the time occupied in the advance or recession ; for the electro-tonic state is rising to a higher or falling to a lower degree during that time, and the change is accompanied by its corresponding evolution of electricity ; but these form no objections to the 0[union that the electro-tonic state is instantly assumed. This peculiar state appears to be a state of tension, and may be considered as erjuivnlent to a current of electricity, at least equal to that produced either when the condition is induced or destroyed. Faraday further supposed that the formation of this state in the neii^fhbourhood of a coil would exert a reaction upon the original current, giving rise to a retardation of it ; but he "was unable at the time to ascertain experimentally whether this Avas so. He even looked — though also unsuccessfully — for a self-induced return current from a conductor of copper through which a strong current was led and then suddenly interrupted, the expected current of reaction being "due to the discharge of its supposed electrotonic state." If we would understand the rather obscure language in which this idea of an electrotonic state is couched, we must try to put ourselves back to the epoch Avhen it was written. At that date the only ideas which had been formulated to explain magnetic and electric attractions and repulsions were founded upon the notion of action at a distance. Michell had propounded the view that the electric and magnetic forces vary, like gravity, according to a law of the inverse squares of the distances. Coulomb, in a series of experiments requiring extraordinary patience as well as delicacy of manipulation, had shown — by an 12S MICHAEL FARADAY. application of Micbell's torsion balance — that in par- ticular cases where the electric changes are concen- trated on small spheres, or where the niagnetic poles are small, so as to act as mere points, this law — which is essentialh' a i^eometric law of point-action — is ajDproximately fultilled. The mathematicians, Laplace and Poisson at tlieir head, had seized on this demonstra- lion and had elaborated their mathematical theories. Before them, thoncdi the research lav for a century unpublished, Cavendish had shown that the onl}' law of force as between one element of an electric chars^e and another compatible with a charge being in equilibrium was the law of inverse squares. But in all these mathematical reasonins^s one thins^ had been quite left out of sight — namely, the possible properties of the intervening medium. Faraday, to whom the idea of mere action at a distance Avas abhorrent, if not unthinkable, conceived of all these forces of attraction and repulsion as efiects taking place by something going on in. fl/e intervening medium, as effects propagated from point to point continuously through space. In his earher work on the electromagnetic rotations he had gro^vn to regard the space around the conducting wire as being affected by the so-called current : and the space about the poles of a magnet he knew to be traversed by curved magnetic lines, invisible indeed, but real, needing only the simplest of expedients — the sprinkling of iron fihngs — to reveal their existence and trend. When therefore he found that these new effects of the induction of one electric cun-ent by another could likewise cross an intervening space, whether empty or filled with material bodies^ A SPAP.K FROM A MAGNET. 1*29 he instinctively songlit to ascribe this propagation of the effect, to a property or state of the niediuni. And linding that state to be different from any state previously kno"\yn, different from the state existing bet^veen f\vo magnets at rest or bet\veen two stationary electric charges, he foUo^ved the entirely philosophical course of exploring its properties and of denoting it by a name which he deemed appropriate. As we shall see. this idea of an electrotonic state recurred in his later researches with new and important conno- tations. He was soon at work again, as we have seen. He experimented, in Januar}', 1832, on the currents produced by the earth's rotation — on the 10th at the round pond in Kensington Gardens, and on the 12th and loth at Waterloo Bridge. '■ This evening." he writes in his notebook under date Februar}' ^, "" at Woolwich, experinienting with magnet,^ and for the lirst time got the magnetic spark myself. Connected ends of a helix into two general ends, and then crossed the wires in such a way that a blow at a h would open them a little [Fig. 10]. Then * The great magnet of the RL-yal S>:ieiety. whieh was at this time lent to AEr. Christie. J 130 MICHAEL FARADAY. bringing a. h against the poles of a magnet, the ends ■^vere disjoined, and bright sparks resnUed." From succeeding "with a steel magnet it was biit a short step to succeed when a natural loadstone was used. The next day we find this entry : — " At home succeeded beautifully with Mr. Daniells magnet. Amalgamation of wires very needful. This is a natural loadstone, and perhaps the first used for the spark." He sent to the Ro3-al Society an account of these and the earlier experiments : his paper on terrestrial magneto-electric induction, and on the force and direction of magneto-electric induction, received the distinction of being read as the Bakerian lecture of the year. The following suramar}* of this second paper is from the pen of Professor T3'ndaU : — He placed a bar of iron in a coil of wire, and lifting the bar into the direction of the dipping needle, he excited by this action a current in the coil. On reversing the bar, a current in the opposite direction rushed through the wire. The same effect was produced, ^Then, on holding the helix in the line of dip, a bar of iron was thrust into it. Here, however, the earth acted on the coil through the intermediation of the bar of iron. He abandoned the bar, and simply* set a copper plate spinning in a horizontal plane ; he knew that the earth's lines of magnetic force then crossed the plate at an angle of about 70'^. \Vhen the plate spun round, the lines of force were intersected and induced currents generated, which produced their proper effect when carried from the plate to the galvanometer. " When the plate was in the magnetic meridian, or in any- other plane coinciding with the magnetic dip, then it^ rotation produced no effect upon the galvanometer." TYNDALL's SaMMARY. 131 At the suggestion of a mind fruitful in suggestions of a profound and philosophic character — I mean that of Sir John Herschel— Mr. Barlow, of Woolwich, had experimented with a rotating iron shell. Mr. Christie had also performed an elaborate series of experiments on a rotating iron disc. Both of them had found that when in rotation the body exercised a ])eculiar action upon the magnetic needle, deflecting it in a manner which Avas not observed during quiescence ; but neither of them was aware at the time of the agent which produced this extraordinary deflection. They ascribed it to some change in the magnetism of the iron shell and disc. But Faraday at once saw that his induced currents must come into play here, and he immediately obtained them from an iron disc. With a hollow brass ball, moreover, he produced the effects obtained by Mr. Barlow. Iron was in no way necessary ; the only condition of success was that the rotating body should be of a character to admit of the formation of currents in its substance ; it must, in other Avords, be a con- ductor of electricity. The higher the conducting power, the more copious Avere the currents. He now passes from his little brass globe to the globe of the earth. He plays like a magician with the earth's magnetism. He sees the invisible lines along which its magnetic action is exerted, and, sAveei)ing his wand across these lines, he evokes this new power. Placing a simple loop of wire round a magnetic needle, he bends its upper portion to the west ; the north pole of the needle immediately swerves to the east ; he bends his loop to the east, and the north pole moves to the west. Suspending a common bar magnet in a vertical position, he causes it to spin round its own axis. Its pole being connected with one end of a galvano- meter wire, and its equator witli the other end, electricity rushes round the galvanometer from the rotating magnet. He remarks upon the *' singular -mJependtn-ce " of the magnetism and the body of the magnet which carries it. The steel behaves as if it were isolated from its own magnetism. And then his thoughts suddenly widen, and he asks himself whether the rotating earth does not generate induced currents as it turns round its axis from west to east. In his experiment 182 MICHAEL FARADAY. with the twirling magnet the galvanometer wire remained at rest ; one portion of the circuit was in motion relatively to another po)-tion. But in the case of the twirling planet the galvanometp.r wire would necessarily be carried along with the earth ; there would be no relative motion. What must be the consequence? Take the case of a telegrapli wire with its two terminal plates dipped into the earth, and sup^tose the wire to lie in the magnetic meridian. The ground underneath the wire is influenced, like the wire itself, by the earth's rotation ; if a current from south to north be generated in the wire, a similar current from south to north would be generated in the earth under the wire ; these currents would run against the same terminal plate, and thus neutralise each other. This inference appears iuevitable, but his profound vision perceived its possible invalidity. He saw that it was at least possible that the difference of conducting power between the earth and the wire might give one an advantage over the other, and that thus a residual or differential current might be obtained. He combined wires of different materials, and caused them to act in opposition to each other, but found the combination ineffectual. The more copious flow in the better conductor was exactly counterbalanced by the resistance of the worst. Still, though experiment Avas thus emphatic, he would clear his mind of all discomfort by operating on the earth itself. He went to the round lake near Kensington Palace, and stretched 480 feet of copper wire, north and south, over the lake, causing plates soldered to the wire at its ends to dip into the water. The copper wire was severed at the middle, and the severed ends connected with a galvanometer. No effect whatever was observed. But though quiescent water gave no effect, moving water might. He therefore worked at Waterloo Bridge for three days, during the ebb and flow of the tide, but without any satisfactory result. Still he urges, " Theoretically it seems a necessary consequence, that where water is flowing there electric currents should be formed. If a line be imagined passing from Dover to Calais through the sea and returning through the land, beneath the water, to Dover, it traces out a circuit of conducting matter, one part of which, THE LAW OF INDUr'TlON. 133 when the water moves up or down the Channel, is cutting the magnetic curves of the earth, whilst the other is relatively at rest There is every reason to believe that currents do run in the general direction of the circuit described, either one way or the other, according as the passage of the waters is up or down the Channel." This w^as written before the sub- marine cable was thought of, and he once informed me that actual observation upon that cable had been found to be in accordance x\ith his theoretic deduction. It may here be apposite to discuss a fundamental question raised in these researches. In Faraday's .\ Fig. U. mind there arose the conviction of a connection be- tween the induction of currents by magnets and the magnetic lines which invisibly fill all the space in the neighbourhood of the magnet. That relation he dis- covered and announced in the following terms : — " The relation which holds between the magnetic pole, the moving wire or metal, and the direction of the current evolved — i.e. the la%v which governs the evolution of electricity by magneto- electric induction, is very simple, though rather difficult to express. If in Fig. 11^ p N represent a horizontal wire passing by a marked [i.e. ' north-seeking '] magnetic pole, so that the direction of its motion shall coincide with the curved line proceeding from below upwards ; or if 134 MICHAEL FARADAY. its motion parallel to itself be in a line tangential to the curved line, but in the creneral direction of the ' CI arrows ; or if it pass the pole in other directions, but so as to cut the magnetic curves* in the same general direction, or on the same side as they would be cut by the Avire if moving along the dotted curved line ; then the current of electricity in the wire is from r to x. If it be carried in the reverse direction, the electric current will be from n to p. Or if the wire be in the vertical position, tigured p' n', and it be carried in similar directions, coinciding with the dotted horizontal curve so far as to cut the magnetic curves on the same side with it, the current will be from p' to xV When resuminof the research in i>ecember, Fara- day investigated the point whether it was essential or not that the rnovino- wire should, in '' cuttincj- " the magnetic curves, pass into positions of greater or lesser magnetic force ; or whether, always intersecting curves of equal magnetic intensity, the mere motion sufficed for the production of the current. He found the latter to be true. This notion of cutting the invisible magnetic lines as the essential act necessary and sufficient for induction was entirely original with Faraday. For long it proved a stumbling-block to the abstract mathematicians, since there was, in most cases, no direct or easy way in which to express the number of magnetic lines that were cut. Neither had any convention been adopted up to that time as " [Orig-inal footnote by Fai-aday.] By mag-iietic curves, I mean the lines of magnetic force, however modi6ed by the juxtaposition of poles, -which would be depicted by iron filings; or those to which a very small magnetic needle would form a tangent. CUTTING THE MAGNETIC LINES, 185 to how to reckon numerically the number of magnetic lines in any given space near a magnet. Later, in 1e amalgamated. When this bundle was used to eonnert the electro-motor it gave but very feeble spark on breaking contact, but the spark was sensibly better when the wires are held together so as to act laterally than when they were opened out from each other, thus showing lateral aetion. Made a larger bundle of the same fine copper wire. There were -i' lengths oi IS feet -2 inches each and the thick terminal pieces oi copper wire 6 inches long and ,' of inch thick. This bundle he ooinpared with a length oi 19 feet ^^ inches of a single copper wire ^ inch in diameter. having about equal sectional area. The latter gave decidedly the largest sparks on breaking circuit. Faraday did not see tit at this time to accept the idea, suggested indeed by himself in 1S31. that these effects of self-induction were the analogue of momentum or inertiii. That explanation he set aside on finding that the same wire when coiled had greater self-inductive action than Avhen straight. Had lie at that time grasped this analogy, he would have seen that the very property which gives rise to the spark at break of circuit also retards the raptid growth of a current : and then the experiment described above would have shown hiiu that Sir W. Snow Harris was right in preferring flat copper ribbon to a round wire of equivalent section as a 152 MICHAEL FARADAY. material for lightning conductors. He was, however, disappointed to find so small a ditibrence between round wires and parallel strands. The memoir as published contains an exceedingl}^ interesting con- clusion : — Notwithstanding that the effects appear only at the making and breakini;' of contact (the current, reniaininjj: unaffected, seemingly, in the interval,) I cannot resist the impression that there is some connected and correspondent effect 1 iroduced by this lateral action of the elements of the electric stream during the time of its continuance. An action of this kind, in fact, is evident in the magnetic relations of the parts of tlie current. Hut admitting (as we may do for the moment) the magnetic forces to constitute the jtower which in'oduces such striking and different results at the commenceuient and termination of a current, still there appears to be a link in the chain of effects — a wheel in the physical mechanism of the action, as yet unrecognised. The tenth scries of researches, on the voltaic battery, though completed in October, 1S84, was not published till June, 1S35. The next research, begun in the autumn of 1835. after a lull of about eii>'ht months, lasted over two years. It was not completed till December, 1837. This investigation took Faraday away from magnetic and electrochemical matters to the old subject of statical electric charges, a subject hitherto untouched in his researches. But he had long brooded over the question as to the nature of an electric charge. Over and over again, as he had Avatched the inductive eftcct of electric currents acting from wire to wire, his mind turned to the old problem of the inductive intluenco — discovered eighty years before, by John ACTIOX IN A MEDIUM. l-^*^ Canton — exerted, apparently at a distance, by clecti-ic charo'es. He had learned to distrust action at .a distance, and now tlie time was ripe for a searchini:^ inquiry as to whether electric ivflwvce, or induction "^" as it was tlien called, was also an action propagated by contiguous actions in the intervening medium. Faraday had rlone no special electric work during the first nine months of 1835. He had worked at a chemical investigation of fluorine through the spring, and in July took a hurried tour in Switzer- land, and returned to work at fluorine. Not till November 3rd does he turn to the subject over which he had been brooding. On that date, intercalated between notes of his chemical studies, filling a dozen pages of the laboratory book, are a magnificent series of speculations as to the nature of charges, and on the part played by the electric — or, as we should now say, the dielectric — medium. They begin thus: — " Have been thinking much lately of the relation of common and voltaic electricity, of induction by the former and decomposition by the latter, and am quite convinced that there must be the closest connection. Will be first needful to make out the true character " — note the phrase^" of ordinary electrical phenomena." '■ The term iinlHrflon appears to have heon originally used, in contradistinction to contact or coi/niict'uii, to connote those effects which apparently are in the class of actions at a distance. Thus we may have induction of a charge by a charge, or of a mngnct- pole by a magnet-polo. To these Faraday had added the induction of a current by a current^ and the induction of a current by a moving magnet. Amid such varyinf^- adaptations of the word in- dia'tion, there is much gain in allotting to the electrostatic induction of charges by charges the distinguishing name of 'influeiwe., as suggested by Priestley. 154 MICHAEL FARADAY. The following notes are for experiment and ob- servation. " Does common electricity reside upon the sur- face of a conductor or upon the surface of the [di-]electric in contact with it ? " He ^oes on to consider the state of a dielectric substance, such as s^lass, when situated between a positively charged and a negatively charged surface, as in a charged Ley den jar, and argues from analogy thus : — " Hence the state of the plate [of glass] under induction is the same as the state of a magnet, and if split or broken would present new P[ositive] and N[egative] surfaces before not at all evident." This speculation was later verified by Matteucci. " Probable that phenomena of induction prove more decidedly than anything else that the electricity is in the [di-]electric not in the conductor." He still worked for a .week or two on fluorine, interposing some experiments on the temperature- limit of magnetisation, but on December 4th decides not to go on with fluorine at present. Then, beginning on December 5th, there follow twenty-nine pages of the laboratory diar^^, illustrated with sketches. He had borrowed from a Mr. Kipp a large deep copper pan thirty-five inches in diameter, and he set to work electrifying it and exploring the distribution of the charges, inside and out, and the inductive effect on objects placed within. Everywhere he is mentally comparing the distribution of the effects with that of the flow of currents in an electrolyte. Before many days he writes : — PREGNANT SUGGESTIONS. 155 "It appears to me at present that ordinar/j and ch'ctrolijfic induction are identical in their first nature, but that the latter is followed by an effect which cannot but from the nature and state of the substances take" place with the former." Then conies this preg- nant suggestion : — " Try induction through a sohd crystalline body as to the consequent action on polarized light." By the end of a Aveek he had begun to suspect that his magnet analogy went farther than he was at first prepared to hold. The action of a magnet was along curved lines of force. So he asks : — " Can induction through air take place in curves or round a corner — can probably be found experi- mentally — if so not a radiating effect." After ten days more he has made another step. " Electricity appears to exist only in 'polarity as in air, glass, electrolytes, etc. Now metals, being con- ductors, cannot take up that poLar state of their own power, or rather retain it, and hence probably cannot retain developed electric forces. " Metals, however, probably hold it for a moment, as other things do for a longer time; an end coming at last to ah." This, it will be observed, is nothint^ more or less than Clerk Maxwell's theory of conduction as beins^ the breakino^ down of an electrostatic strain. In January, 1836, followed the famous experiment of building a twelve-foot cube, which when electrified exteriorly to the utmost extent, showed inside no trace of electric forces. The account in the unpublished 156 MICHAEL FARADAY. MS. of the lal)oratory book is, as is the case with so many of these middle-period researches, much fuller than the published re'--^urae of them in the " Experimental Researches." All throu^-h 1S3(J he was still at work. Even Avheli on a holida}' in the Isle of "Wio'ht, in Aus^ust, he t<^ok his notebook with him, and writes : — " After much consideration (here at Ryde) of the manner m which the electric forces are arranged in the various phenomena generally, I have come to certain conchisions Avhich I will endeavour to note down without connnitting m3'self to any opinion as to the cause of electricity, i.e. as to the nature of the poAver. If electricity exist independently of matter, then I think that the hypothesis of one fluid Avill not stand asfainst that of two fluids. There are, I think, evidently, what I may call two elements of power of equal force and acting towards each other. These may conventionally be represented by oxygen and hydrogen, which represent them in the voltaic battery. But these powers ma}- be distinguished only hi/ du'cc- tion, and may be no n:iore separate than the north and south forces in the elements of a mametic needle. They may be the polar points of the forces originally placed in the particles of matter : and the description of the current as an axis of poAver which I have formerly driven suo-o-ests some similar o-eneral im- pression for the forces of quiescent electricity. Law of electric tension might do, and though I shall use the terms positive and negative, by them I merel}^ mean the termini of such lines." Rio-ht on until November 30th, 1837, this research ACTION AT A DISTANCE UNTHINKABLE. 157 was continued. The sminnary of this and the succeed- ing researches of 1^38 on the same subject, drawn up by Professor Tyndall,^ is at once so masterly and so impartial that it cannot be bettered. It is therefore here transcribed without alteration. His first great paper on frictiunal electricity was sent to the Royal iSociety on November 30, 1837. We here tiad him face to face with an idea which beset liis mind throughout his whole subseijuent life— the idea of y simple intuition he sees th^t * " Faraday as a Discoverer," p, 67. t Newton's third letter to Bentley. 158 MICHAEL FARADAY. action at a distance must be exerted in straight lines. Gravity, he knows, will not turn a corner, but exerts its pull along a right line ; hence his aim and efibrt to ascertain whether electric action ever takes place in curved lines. This once proved, it would follow that the action is airried on by vieans of a medium surrounding the electrified bodies. His experi- ments in 1837 reduced, in his opinion, this point to demonstra- tion. He then found that he could electrify by induction an insulated sphere placed completely in the shadow of a body which screened it from direct action. He pictured the lines of electric force bending round the edges of the screen, and re- uniting on the other side of it ; and he proved that in many cases the augmentation of the distance between his insulated sphere and the inducing body, instead of lessening, increased the charge of the sphere. This he ascribed to the coalescence of the lines of electric force at some distance behind the screen. Faraday's theoretic views on this subject have not received general acceptance, but they drove him to experiment, and experiment with him was always prolific of results. By suit- able arrangements he places a metallic sphere in the middle of a large hollow^ sphere, leaving a space of something more than half an inch between them. The interior sphere was insulated, the external one uninsulated. To the former he communicated a de6nite charge of electricity. It acted by induction upon the concave surface of the latter, and he examined how this act of induction was affected by placing insulators of various kinds between the two spheres. He tried gases, liquids, and solids, but the solids alone gave him positive results. He constructed two instruments of the foregoing description, equal in size and similar in form. The interior sphere of each communicated with the external air by a brass stem ending in a knob. The apparatus was virtually a Leyden jar, the two coatings of Avhich were the two spheres, with a thick and variable insulator between them. The amount of charge in each jar was deter- mined by bringing a proof-plane into contact with its knob, and measuring by a torsion balance the charge taken away. He first charged one of his instruments, and then dividing the charge with the other, found that when air intervened in both SPECIFIC INDUCTIVE CAPACITY. 159 cases, the charge was equally divided. But when shell-lac, sulphur, or spermaceti was interposed between the two spheres of one jar, while air occupied this interval in the other, then he found that the instrument occupied by the "solid dielectric" took more than half the original charge. A portion of the charge was absorbed in the dielectric itself. The electricity took time to penetrate the dielectric. Immediately after the Fig. It. discharge of the apparatus no trace of electricity was found upon its knob. But aftei a time electricity was found there, the charge having gradually returned from the dielectric in which it had been lodged. Different insulators possess this power of permitting the charge to enter them in difierent degrees. Faraday tigured their particles as polarised, and he concluded that the force of induction is propagated from particle to particle of the dielectric from the inner sphere to the outer one. This power of propagation possessed by in- sulators he calls their " Hpecific Inductive Capacity T Faraday visualises with the utmost clearness the state of his contiguous particles ; one after another they become 160 MICHAEL FARADAY. charged, each succeeding particle dependiiii;" for its charge upon its predece.-ssor. And now he seeks to break do^\^i the Avail of partition between conductors and insulators. " Can Ave not," he says, "by a gradual chain of association carry up discharge from its occurrence in air through spermaceti and water to solutions, and then on to chloricies, oxides, and metals, without any essential change in its character?" Even copper, he urges, offers a resLstance to the transmission of electricity. The action of its particles ditfers from those of an insulator only in degree. They are charged like the particles of the insulator, but they discbarge Avith greater ease and rapidity ; and this rapidity of molecular discharge is Avhat Ave call conduction. Conduction, then, is ahvays preceded by atomic induction ; and Avhen through some quality of the body, Avhich Faraday does not define, the atomic discharge is rendered sIoav and difficult, conduction passes into insulation. Though they are often obscure, a fine vein of philosophic thought runs through these investigations. The mind of the philosopher dwells amid those agencies which underlie the visible phenomena of induction and conduction ; and he tries by the strong light of his imagination to see the very molecules of his dielectrics. It Avould, hoAvever, be easy to criticise these researches, easy to shoAv the looseness, and sometimes the inaccuracy, of the phraseology emjiloyed ; but this critical spirit Avill get little good out of Faraday. Rather let those Avho ponder his Avorks seek to realise the object he set before him, not permitting his occasional vagueness to interfere with their appreciation of his speculations. We may see the ripples, and eddies, and vortices of a flowing stream, AA^thout being able to resolve all these motions into their constituent elements ; and so it sometimes strikes me that Faraday clearly saAv the play of fluids and ethers and atoms, thougli his previous train- ing did not enable him t(t rt^solve what he saAv into its con- stituents, or descritie it in a manner satisfactory to a mind versed in mechanics. And then again occur, I confess, dark sayings, difficult to be understood, Avhich disturb my confidence in this conclusion. It must, however, ahvays be remembered that he works at the very boundaries of our knoAvledge, and CABLE RETAltDATJOX PREIUCTED. 161 that his mind habitually dwells in the '' boundless contiguity of shade " by which that knowledge is surrounded. In the researches now under review the ratio of speculation and reasoning to experiment is far higher than in any of Faraday's previous A^orks. Amid much that is entangled and dark we have flashes of wondrous insight and utterances which seem less the product of reasoning than of revelation. I will confine myself here to one example of tliis divining power : — By his most ingenious device of a rapidly rotating mirror, Wlieatstone had proved that electricity recjuired time to pass through a wire, the current reaching the middle of the wire later than its two ends. "If," says Faraday, "the two ends of the wire in Professor Wheatstone's experiments were immediately connected with two large insulated metallic surfaces exposed to the air, so that the primary act of induc- tion, after making the contact for discharge, might be in part removed from the internal portion of the wire at the first instance, and disposed for the moment on its surface jointly with the air and surrounding conductors, then I venture to anticipate that the middle spark would be more retarded than before. And if those two plates were the inner and outer coatings of a large jar or Leyden battery, then the retardation of the spark would be much greater." This was only a prediction^ for the experiment was not made. Sixteen years subsequently, however, the proper conditions came into play, and Faraday was able to show that the observations of Werner Siemens and Latimer Clark on subterraneous and submarine wires were illustrations, on a grand scale, of the principle which he had enunciated in 1838. The wires and the sur- rounding water act as a Leyden jar, and the retardation of the current predicted by Faraday manifests itself in every message sent by such cables. The meaning of Faraday in these meniou's on induction and conduction is, as I have said, by no means always clear ; and the difficulty will be most felt by those who are best trained in ordinary theoretic conceptions. He does not know the reader's needs, and he therefore does not meet them. For instance, he speaks over and over again of the L 162 MICHAEL FARADAY. impossibility of charging a body with one electricity, though the impossibility is by no means evident. The key to the ditticulty is this. He looks upon every insulated conductor as the inner coating of a Leyden jar. An insulated sphere in the middle of a room is to his mind such a coating ; the Avails are the outer coating, while the air between both is the insulator, across which the charge acts by induction. AYithout this reaction of the -walls upon the sphere, you conld no more, according to Faradny, charge it with electricity than you could charge a Leyden jar, if its outer coating were removed. Distance with him is immaterial. His strength as a generaliser enables him to dissolve the idea of magni- tude ; and if you abolish the walls of the room— even the earth itself — he would make the sun and planets the outer coating of his jar. I dare not contend that Faraday in these memoirs made all these theoretic positions good. But a pure vein of philosophy runs through these writings; while his experiments and reasonings on the forms and phenomena of electrical discharge are of imperishable importance. In another part of the tAvelfth memoir, not in- eluded in the above suminar}^ Farada}^ deals with the disruptive discharge, and with the nature of the spark under varying conditions. This is continued on into the thirteenth memoir, read February, 1838, and is extended to the cases of " brush " and " glow " discharges. He discovered the existence of the very remarkable phenomenon of the " dark " discharge near the cathode in rarefied air. He sought to correlate all the various forms of discharge, as show- ing the essential natm'e of an electric current. " If a ball be electrified positively/' he says, " in the middle of a room, and be then moved in any direction, effects will be produced, as if a current in the same direction (to use the conventional mode OOrNAGE OF NEW WORDS. 163 of expression) had existed." This is the theory of convection currents later adopted by Maxwell, and verified by experiment by Rowland in 1876. In the course of this research on induction, Faraday had, as we have seen, been compelled to adopt neAV ideas, and therefore to adopt new names to denote them. The term dielectric for the medium in or across which the electric forces operate was one of these. As in previous cases, he consulted with his friends as to suitable terms. In this in- stance the following letter from Wlieweh explains itself. The letter to which it is a reply has not been preserved, but the reference to Faraday's ob- jection to the word current may be elucidated by a comparison with what Faraday Avrote in criticism of that word on pages 146 and 212. [Rev. IF. Whewell to J/. Faraday.] Tkin. Coll., Cambridge, Oct. 14, 1837. My dear 8ik, — I am always glad to hear of the progress of your researches, and never the less so because they require the fabrication of a new word or two. Such a coinage has always taken place at the great epochs of discovery ; like the medals that are struck at the beginning of a new reign : — or rather like the change of currency produced by the accession of a new sovereign ; for their value and inllueiice consists in their coming into common circulation. I am not sure that I understand the view^s which you are at present bringing into shape sufficiently well to suggest any such terms as you think you want. I think that if I could have a quarter of an hour's talk with you I should probably be able to construct terras that would record your new notions, so far as I could be made to understand them better than I can by means of letters : for it is difficult 164 MICHAEL FARADAY. without question and discussion to catch the precise kind of relation which you want to express. However, by way of beginning such a discussion, I woukl ask you whether you want abstract terms to denote the different and related conditions of the body which exercises and the body which suffers induction ? For though both are active and both passive it may still be convenient to suppose a certain ascendancy on one side. If so would two such words as inductricity and inducteity answer your purpose '? They are not very monstrous in their form ; and are sufficiently distinct. And if you w^int the corresponding adjectives yo\i may call the one the inductric, and the other the indncteous body. This last word is rather a startling one ; but if such relations are to be expressed, terminations are a good artifice, as we see in chemistry : and I have no doubt if you give the world facts and laws which are better expressed with than without such solecisms, they will soon accommodate to the phrases, as they have often done to worse ones. But I am rather in the dark as to whether this is the kind of relation which you want to indicate. If not, the attempt may perhaps serve to shew you where my dulness lies. I do not see my way any better as to the other terms, for I do not catch your objection to current., which appears to me to be capable of jogging on very well from cathode to anode^ or vice versa. As for positive and negative, I do not see why cathodic and anodic should not be used, if they will do the service you want of them. I expect to be in London at the end of the month, and could probably see you for half an hour on the 1st of November, say at 10, 11, or 12. But in the mean time I shall be glad to hear from you whether you can make anything of such conundrums as I have mentioned, and am always yours very truly, W. Whewell. M. Faraday Esq"* Royal Institution, LATERAL ACTIONS OF CURRENT. 105 The concluding part of the thirteenth memoir, in "which these new terms are used, is an exceedingly striking speculation on the lateral or transverse effects of the current. In caUing special attention to them, he says : " I refer of course to the magnetic action and its relations ; but though this is the only recognised lateral action of the current, there is great reason for believing that others exist and would by their discovery re"v\^ard a close search for them." He seems to have had an instinctive per- ception of something that eluded his grasp. Not until after Maxwell had given mathematical form to Faraday's own suggestions was this vision to be realised. He is dindy aware that there appears to be a lateral tension or repulsion possessed by the lines of electric inductive action ; and onward runs his thought in free speculation : — When current or discharge occurs between two bodies, previously under inductrical relations to each other, the Unes of inductive force will weaken and fade away, and, as their lateral repulsive tension diminishes, will contract and ultimately disap|>ear in the line of discharge. May not this be an effect identical with the attractions of similar currents ? i.e. may not the passage of static electricity into current electricity, and that of the lateral tension of the lines of the inductive force into the lateral attraction of lines of similar discharge, have the same relation and de- pendences, and run parallel to each other? Series fourteen of the memoirs is on the nature of the electric force and on the relation of the electric and magnetic forces, and comprises an in- conclusive inquiry as to a possible relation between 166 MTCKAKL FARADAV. specitic inductive capacity and axes of crystallisation in crystalline dielectrics — a relation later assumed as true by Maxwell even before it was demonstrated by Von Boltzmann. In this memoir, too, occurs a description of a sin^iple but efi'ective induction balance. Then he asks what happens to insulating substances, such as air or sulphur, when they are put i-n a place where the magnetic forces are varying ; they ought, he thinks, to undergo some state or condition corre- sponding to the state that causes currents in metals and conductors, and, further, that state ought to he one of tension. "I have," he says, "by rotating non-conducting bodies near magnetic poles, and poles near them, and also by causing powerful electric currents to be suddenly formed and to cease around and about insulators in various directions, en- deavoured to make some such state sensible, but have not succeeded." In short, he was looking for direct evidence of the existence of what Maxwell called " displacement currents " — evidence which was later found independently by the author and by Rilntgen. And, again, there rises in his mind a perception of that decfrofonic •'^faf.e which had haunted his earlier researches as a something im- posed upon the surrounding medium during the growth or dying of an electric current. In these years (IS35-I83S) Faraday was still in- defaticfable in his lecture duties. In 1835 he grave four Friday discourses, and in May and June eight afternoon lectures at the Royal Institution on the metals: also a course of fourteen lectures on elec- tricity to the medical students at St. George's INCESSANT ACTIVITIES. 167 Hospital. In 1S36 he published in the Pliilomphical Magazine a paper on the magnetism of the metals — notable as containing the still unverified specu- lation that all metals would become magnetic in the same way as iron if only cooled to a sufficiently low temperature — and three other papers, including one on the " passive " state of iron. He gave four Friday discourses and six afternoon lectures on heat. In 1837 also four Friday night discourses and six afternoon lectures were delivered. In 1838 three Friday discourses and eight afternoon lectures on electricity, ending in June with a distinct enun- ciation of the doctrine of the transformations of " force " {i.e. energy) and its indestructibility, afforded evidence of his industry in this respect. At the same time he was giving scientitic advice to the authorities of Trinity House as to their lighthouses. The laborator}^ notebook for March to August, 1838, shows a long research, occupying nearly 100 folio pages, on the relation of specific inductive capacity to crystalline structure. This is followed by some experiments upon an electric eel, at the Royal Adelaide Gallery, with some unpublished sketches of the distribution in the water of the currents it emits. He proved, Avitli great satisfaction, that the currents it gave were capable of producing magnetic effects, sparks, and chemical decompo- sition. These observations were embodied in the fifteenth series of memoirs. One entry in the laboratory book, ot date April 5th, 1838, is of great interest, as showing hoAv his mind ever recurred to the possibility of finding a 168 MICHAEL FARADAY. connection between optical and electric phenomena : " Must try polarized light across a crystalline di- electric under charge. Good reasons perhaps now evident why a non-crystalline dielectric should have no effect." Faraday was noAV feeling greatly the strain of all these years of work, and in 1839 did little re- search until the autumn. Then he returned to the question of the origin of the electromotive force of the voltaic cell, and by the end of the year completed two long papers on this vexed question; the}^ formed the sixteenth and seventeenth series, and conclude the memoirs of this second period. In the eighth scries, completed in April, 1884, on the ** Electricity of the Voltaic Pile," Faraday had dealt with the question — at that time a topic of excited controversy — of the origin of the electro- motive force in a cell. Volta, who knew nothing of the chemical actions, ascribed it to the contact of dissimilar metals, whilst Wollaston, Becquerel, and De la Rive considered it the result of chemical actions. The controversy has long ceased to interest the scientitic world ; for, Avith the recognition of the principle of the conservation of energy, it be- came evident that mere contact cannot provide a continuing supply of energy. It Avould now be altogether dead but for the survival of a belief in the contact theory on the part of one of the most honoured veterans in science. But in the years 1834 to 1840 it was of absorbing interest. Faraday's work quietly removed the props which supported the older theory, and it crumbled away. He found THE CONTACT THEORY OF ELECTRICITY. 169 that the chemical and electrical effects in the cell were proportional one to the other, and inseparable. He discovered a way of making a cell without any metallic contacts. He showed that without chemical action there was no current produced. But his re- sults were ignored for the time. After six years Faraday reopened the question. Again the admir- able summary of Professor Tyndall is drawn upon for the following account :— The memoir on the "Electricity of the Voltaic Pile," published in 1834, appears to have produced but little im- pression upon the supporters of the contact theory. These indeed were men of too great intellectual weight and in- ,sight lightly to take up, or lightly to ahandi)n, a theory. Faraday therefore resumed the attack in two papers com- municated to the Royal Society on February 6 and March 19, 1840. In these papers he hampered his antagonists by a crowd of adverse experiments. He hung difficulty after difficulty about the neck of the contact theory, until in its efforts to escape from his assaults it so changed its character as to become a thing totally difi"erent from the theory pro- posed by Volta. The more persistently it was defended, however, the more clearly did it show itself to be a congeries of devices, bearing the stamp of dialectic skill rather than that of natural truth. In conclusion, Faraday brought to bear upon it an argu- ment which, had its full weight and purport been understood at the time, would have instantly decided the controversy. "The contact theory," he urged, "assumes that a force which is able to overcome powerful resistance, as for instance that of the conductors, good or bad, through which the current passes, and that again of the electrolytic action where bodies are decomposed by it, can arise out of nothing ; that without any change in the acting matter, or the consumption of any generating force, a current shall be produced which shall 170 MICHAKL FARADAY. go on for ever a^^aiiist a coiiHlruit ix'Mistance, ov nuly he ■stopped, as in the voltaic trouKli, l>y the ruins which its exertion has lieaped up in its own course. Tl)is would indeed be ri rvado}!. of potver^ and is like no other force in nature. We have many processes by which iha form of tlie ])()wer may be so chan;^t<)ii of one into tlic other takes y^lace. So we can cha,ti;^^e chemical force into the electric current, or the cmient into chemiral force. The lieautifid experiments of Seebeck and Peltier sliow tJic convertibility of heat and electricity; and others by Oersted and myself show the convcTtibility of electricity and magnetism. />/// /,// //o rv/.s-r, iu,l ciwn, hi, (ItoHc of the iiyranotas fD,— * ''I count upon you as one uf those whose free hearts have pleasure in my success, and [ am very grateful to you for it. I have had your hist letter by mo on my desk for several weeks, intending to ansAver it ; but absolutely I have not been able, for of late I have shut myself up in my laboratory and wrought, to the exclusion of every- thing else. I heard afterwards that even your brother had called on one of these days and been excluded. Well, a part of this result is that which you have heard, and iiiy paper was read to the Royal Society, 1 believe, last Thursday, for I was not there ; and I also understand there have been notices in the Athenceum, but I have not had time to see them, and I do not know how they are done. However, I can refer you to the Times of last Saturday (November 29th) for a very good abstract of the paper. I do not know who put it in, but it is well done, though brief. To that account, therefore, I will refer you. For I am still so involved in discovery that I have hardly time for my meals, and am here at Brighton both to refresh and work my head at once, and I feel that unless I had been here, and been careful, I could not have continued my labours. The consequence lias been that last ^londay I announced to our members at the Hoyal Institution another discovery, of which I will give you the pith iu a few words. The paper will go to the Eoyal Society next week, and probably be read ns shortly after as they can there find it convenient. Many years ago I worked upon optical glass, and made a vitreous compound of silica, Ijoracic acid, and lead, which I will now call heavy glass, and which Amici uses in some of his microscopes ; and it w^as this substance which enabled me first to act on light by magnetic and electric forces. Now, if a square bar of this substance, about half an inch tliick and two inches long, be very freely suspended between the poles of a powerful horse-shoe electro-magnet, immediately that the magnetic force is developed, the bar points ; but it does not 186 MICHAEL FARADAY. point from pole to pole, but equatorially or across the magnetic lines of force— i.e. east and west in respect of the north and south poles. If it be moved from this position it returns to it, and this continues as long as the magnetic force is in action. This efiect is the result of a still simpler action of the magnet on the bar than what appears by the experiment, and which may be obtained at a single magnetic pole. For if a cubical or rounded piece of the glass be suspended by a fine thread six or eight feet long, and allowed to hang very near a strong magneto-electric pole (not as yet made active), then on render- ing the pole magnetic the glass will be repelled, and continue repelled until the magnetism ceases. This effect or power I have worked out through a great number of its forms and strange consequences, and they will occupy two series of the *' Experimental Eesearches." It belongs to (til maUer (not magnetic, as iron) without exception, so that every substance l>elongs to the one or the other class— magnetic or diamagnetic bodies. The law of action in its simple form is that such matter tends to go from strong to weak points of magnetic force, and in doing this the substance will go in either direction along the magnetic curves, or in. either direction across them. It is curious that amongst the metals are found bodies possessing this property in as high a degree as perhaps any other substance. In fact, I do not know at present whether heavy glass, or bismuth, or phosphorus is the most striking in this respect. I have v^xy little doubt that you have an electro-magnet strong enough to enable you to verify the chief facts of pointing equatorially and repulsion, if you will use bismuth carefully examined as to its freedom from mngnetism, and making of it a bar an inch and a half long, and one-third or one-fourth of an inch wide. Let me, how- ever, ask the favour of your keeping this fact to yourself for two or three weeks, and preserving the date of this letter as a record. I ought (in order to preserve the respect due to the Royal Society) not to write a description to anyone until the l^aper has been received or even read there. After three weeks or a month I think you may use it, guarding, as I am sure you will do, my right. MAGNETIC EXPERIMENTS. 187 And now, my dear friend, I mu.st conclude, and hasten to work again. But first give my kindest respects to Madame de la Rive, and many thanks to your brother for his call. Ever your obedient and affectionate friend, M. Far.'VDAy. The discovery of diamagnetisni which Faraday thus announced was in itself a notable achievement. As Tyndall points out, the discovery itself was in all probability due to Faraday's hal.tit of not regarding as final any negative result of an experiment until he had brought to bear upon it the most powerful resources at his command. He had tried the effects of ordinary magnets on brass and copper and other materials commonly considered as non-magnetic. But when, for the purpose of the preceding research on the relation of magnetism to light, he had deliberately procured electromagnets of unusual power, he again tried what their effect might be upon non-magnetic stuffs. Suspending a piece of his heavy glass near the poles in a stirrup of writing- paper slung upon the end of a long thread of cocoon silk, he found it to experience a strong mechanical action when the magnet was stimulated by turning on the current. His precision of description is characteristic : — I shall have such frequent occasion to refer to two chief positions of position across the magnetic field, that, to avoid periphrasis, I will here ask leave to use a term or two conditionally. One of these directions is that from pole to pole, or along the lines of magnetic force, I will call it the axial direction ; the other is the direction perpendicular to this, and across the line of magnetic force and for the time, 1>^H MICHAEL FAIIADAY. and as respects the space between the poles, I will eiill it the e'luaiorial direction. Xote the occurrence in the above passage for the first tune of the term " the magnetic field."' Faraday's description of the discover)' continues as follows : — The bar of silicated borate of lead or heavy glass already described as the substance in which magnetic forces were first made effectually to bear on a ray of light, and which is 2 inches long, and about O'") inch wide and thick, Avas suspended centrally between the magnetic poles, and left until the effect of torsion was over. The magnet was then thrown into action -^m WW Fig. 19. by making contact at the voltaic battery. Immediately the bar moved, turning round its point of suspension, into a position across the magnetic curve or line of force, and, after a few vibrations, took up its place of rest there. On being displaced by hand from this position it returned to it, and this occurred many times in succession. Either end of the bar indifferently went to either side of the axial line. The determining circumstance was simply inclination of the bar one way or the other to the axial line at the beginning of the experiment. If a ]),irticular or marked end of the bar were on one. side of the magnetic or axial line when the magnet was rendered active, that end went further outwards until the bar had taken up the equatorial position. . . . Here, then, we have a magnetic bar which points east and west in relation to north and south poles — i.e. points perpendicularly to the lines of magnetic force. . . . DIAMAGNETIC LAWS. 189 To produce these effects of pointing across the magnetic carves, the form of the heavy glass must be long. A cube or a fragment approaching roundness in form will not point; but a long piece will. Two or three rounded pieces or cube.-:;, placed side by aide in a paper tray, so as to form an oblong accumulation, .will also point. Portions, however, of any form are repelled ; so if two pieces be hung up at once in the axial line, one near each pole, they are repelled by their respective j)oles, and approach, seeming to attract each other. Or if two pieces be hung up in the equatorial line, one on each side of the axis, then they both recede from the axis, seeming to repel each other. From the little that has been said, it is evident that the bar presents in its motion a complicated result of the force exerted by the, magnetic power over the heavy glass, and that when cubes or spheres are employed a much simpler indication of the effect may be obtained. Accordingly, when a cube was thus used with the two poles, the eS'ect was repulsion or recession from either pole, and also recession from the magnetic axis on either side. So the indicating particle would move either along the magnetic curves or across them, and it w^ould do this either in one direction or the other, the only constant point being that its tendency was to move from stronger to weaker places of magnetic force. This appeared much more simply in the case of a single magnetic pole, for then the tendency of the indicating cube or sphere was to move outwards in the direction of the magnetic lines of force. The appearance was remarkably like a case of weak electric repulsion. The cause of the pointing of the bar, or any oblong arrangement of the heavy glass, is now evident. It is merely a result of the tendency of the particles to move outwards, or into the positions of weakest magnetic action. When the bar of heavy glass is immersed in water, alcohol, or yether, contained in a vessel between the poles, all 190 MICHAEL FARADAY. the preceding effects occur— the h^v points and the cube recedes exactly ia the same manner as in air. The effects ei^ually occur in vessels of \vood, stone, eartb, copper, lead, silver, or any of those substances which belong to the diamagnetic class. I have obtained the same equatorial direction and motions of the heavy glass bar as those just described, but in a very feeble degree, by the use of a good common steel horseshoe magnet. Then he goes on to enumerate the many bodies of all sorts : crystals, powders, liquids, acids, oils ; organic bodies such as wax, olive-oil, wood, beef (fresh and dry), blood, aj^ple, and bread, all of which were found to be dianiacrnetic. On this he remarks : — o It is curious to see such a list as this of bodies presenting on a sudden this remarkable property, and it is strange to find a piece of Avood, or beef, or apple, obedient to or repelled by a magnet. If a man could be suspended with sufficient delicacy after the manner of Dufay, and placed in the magnetic field, he would point ecjuatorially, for all the substances of which he is formed, including the blood, possess this property. A few bodies were found to be feebly magnetic, including paper, sealing-wax, china ink, asbestos, fluorspar, peroxide of lead, tourmaline, plumbago, and charcoal. As to the metals, he found iron, cobalt, and nickel to stand in a distinct class. A feeble magnetic action in platinum, palladium, and titanium was suspected to be due to traces of iron in them. Bismuth proved to be the most strongly diamagnetic, and was specially studied. The repellent effect between bismuth and a magnet had indeed been casually observed twice in the prior history of THE MAGNETIC BRAKE. 191 science, first by Bnigmans, then by Le Baillif. Faraday, with chai\a,cteristic frankness, refers to his having a "vague impression" that the repulsion of bismuth by a magnet had been observed before, though unable at the time of writing to recollect any reference. His own experiments ran over the whole range of substances, however, and demonstrated the universal existence in greater or less degree of this magnetic nature. Certain differences observed be- tween the behaviour of bismuth and of heavy glass on the one hand, and of copper on the other hand, though all are diamagnetic, led him to note and describe some of the pseudo-diamagnetic effects which occur in copper and silver, in consequence of the induction in them of eddy-currents, from which heavy- glass and bismuth are, by their inferior electric conductivity, comparatively free. He described the beautiful and now classical experiment of arresting, by turning on the exciting current, the rotation of a copper cylinder spinning between the poles of an electromagnet. Faraday continued to prosecute this newest line of research, and at the end of December, 1845, presented another memoir (the twenty-first series of the Experi- mental Researches) to the Eoyal Society. He had now examined the salts of iron, and had found that every salt and compound containing iron in the basic part was magnetic, both in the solid and in the liquid state. Even prussian-blue and green bottle-glass were magnetic. The solutions of the salts of iron were of special importance, since they furnish the means of making a magnet which is for the time 192 MICHAEL FARADAY. liquid, transparent, and, within certain linnts, adjust- able in strength. His next step was to examine how bodies beha"\-ed when innnersed in some surrounding medium. A Aveo.k sokition of iron, enclosed in a ver}- thin glass tube, though it pointed axially when hung in air, pointed equatorially when immersed in a stronger solution. A tube full of air pointed axially, and was attracted as if magnetic when surrounded with w^ater. Substances such as bismuth, copper, and phosphorus are, hoAvever, highly diamagnetic w^hen suspended in vacuo. Such a view would n:ia'ke viere space magnetic. Hence Faraday inclined at first to the opinion that diamagnetics had a specific action antithetically distinct from ordinary magnetic action. SeA'eral times he pointed out that all the phenomena resolve themselves simply into this, that a portion of such matter as is termed diamagnetic tends to move from stronger to places or points of weaker force in the mametic field. He does, indeed, hazard the suggestion that the phenomena might be explained on the assumption that there was a sort of diamag- netic polarit}- — that magnetic induction caused in them a contrar}^ state to that which it produced in ordinary magnetic inatter. But his own experi- ments failed to support this view, and, in oppo- sition to Weber and Tyndall, he maintained afterwards the non-polar nature of diamagnetic action. In 1846 Faraday gave two Friday night discourses on these magnetic researches, one on the cohesive force of water, and one on Wheatstone's electro- magnetic chronoscope. At the conclusion of the THOUGHTS ON KAY VIBRATIONS. 198 last-named he said that he was induced to utter a specuhition which had long been gaining strength in his mind, that perhaps those vibrations by which radiant energies, such as light, heat, actinic rays, etc., convey their force through space are not mere vibrations of an rether, but of the lines of force which, in his view, connect different masses, and so Avas inclined, in his own phrase, " to dismiss the aether." In one of his other discourses he made the suggestion that we might " perhaps hereafter obtain magnetism from light." The speculation above referred to is of such intrinsic importance, in view of the developments of the last decade, that it compels further notice. Faraday hims'elf further expanded it in a letter to Richard Phillips, which Avas printed in the Philo- sophical Magazine for May, 1846, under the title " Thoughts on Ray- vibrations." In this avowedly speculative paper Faraday touched the highest point in his scientific writings, and threw out, thouo-h in a tentative and fragmentary way, brilliant hints of that which his imagination had perceived, as in a vision ; — the doctrine now known as the electromagnetic theory of light. At the dates when the earlier biographies of Faraday appeared, neither that doctrine nor this paper had received the recognition due to its importance. Tyndall dismisses it as "one of the most singular speculations that ever emanated from a scientitic man." Bence Jones just mentions it in half a line. i)r. Gladstone does not allude to it. It therefore seems expedient to give here some extracts from the letter itself: — N 194 MICHAEL FARADAY, THOUGHTS ON RAY- VIBRATIONS. To Rlchnrd Phillips, Esq. Dear Sir,— At your request, I will endeavour to convey to you a notion of that which I ventured to say at the close of the last Friday evening meeting f. . . ; but, from firs to last, understand that I merely threw out, as matter for speculation, the vague impressions of my mind, for I gave nothing as the result of sufficient consideration, or as the settled conviction, or even probable conclusion at which I had arrived. The point intended to be set forth for the consideration of the hearers was whether it was not possible that the vibrations— which in a certain theory are assumed to account for radiation and radiant phenomena — may not occur in the lines of force which connect particles, and consequently masses, of matter together — a notion which, as far as it is admitted, will dispense with the iether, which, in another view, is supposed to be the medium in which these vibra- tions take place. Another consideration bearing conjointly on the hypo- thetical view, both of matter and radiation, arises from the comparison of the velocities with which the radiant action and certain powers of matter are transmitted. The velocity of light through space is about 190,000 miles* a second. The velocity of electricity is, by the experiments of Wheatstone, shown to be as great as this, if not greater. The light is supposed to be transmitted by vibrations through an aether which is, so to speak, destitute of gravitation, but infinite in elasticity ; the electricity is transmitted through a small metallic wire, and is often viewed as transmitted by vibrations also. That the electric transference depends on the forces or powers of the matter of the wire can hardly be doubted when * Subsequent investigation has reduced this figure to about 186,400 miles per second, or about 30,000,000,000 centimetres per second. LATEKAL VIBRATIONS. 195 we consider the different conductibility of the various metallic and other bodies, the means of afFectinf^ it by heat or cold, the way in which conducting bodies by combination enter into the constitution of non-conducting substances, and the contrary, and the actaal existence of one elementary body (carbon) both in the conducting and non-conducting state. The power of electric conduction, being a transmission of force equ;d in velocity to that of ligbt, appears to be tied up in and dependent upon the properties of the matter, and is, as it were, existent in them. In experimental philosophy we can, by the phenomena presented, recognise various kinds of lines of force. Thus Fig. 20. there are the lines of gravitating force, those of electrostatic induction, those of magnetic action, and others partaking of a dynamic character might be perhaps included. The lines of electric and magnetic action are by many considered as exerted through space like the lines of gravitating force. For my own part, I incline to believe that when there are inter- vening particles of matter— being themselves only centres o force — they take part in carrying on the force through the line, but that when there are none the line proceeds through space. Whatever the view adopted respecting them may be, we can, at all events, affect these lines of force in a manner which may be conceived as partaking of the nature of a shake or lateral vibration. For suppose two bodies, a b, distant from each other, and under mutual action,* and therefore * The accompanying diagram (Fig. 20) waa not given by Fara- day. It was pencilled by the author more than twenty years ago in the margin of his copy of Faraday's ''Experimental Researches," vol. iii., p. 450, opposite this passage. 196 MICHAEL FARADAY. connected by lines of force, and let us fix our attention upon one resultant of force liavint; an invariable direction as regards space ; if one of the bodies move in the least degree right or left, or if its power be shifted for a moment within the mass (neither of these cases being difficult to realise if a or b be either electric or magnetic bodies), then an eflect ecinivalent to a lateral disturbance will take place in the resultant upon which we are fixing our attention, for either it will increase in force whilst the neighbouring resultants are diminishing, or it will fall in force while they are increasing. The view which 1 am so bold as to put forth considers, therefore, radiation as a high species of vibration in the lines of force which are known to connect particles, and also masses, of matter together. It endeavours to dismiss the ;tther, but not the vibrations. The kind of vibration which, I believe, can alone account for the wonderful, varied, and beautiful phenomena "of polarisation is not the same as that which occurs on the surface of disturbed water or the waves of sound in gases or liquids, for the vibrations in these cases are direct, or to and from the centre of action, whereas the former are lateral. It seems to me that the resultant of two or more lines of force is in an apt condition for that action, which may be considered as ec[uivalent to a lateral vibration ; whereas a uniform medium like the a?ther does not appear apt, or more apt than air or water. ^The occurrence of a change at one end of a line of force easily suggests a consequent change at the other. The propagation of light, and therefore probably of all radiant action, occupies time ; and that a vibration of the line of force should account for the phenomena of radiation, it is necessary that such vibration should occupy time also. And now, my dear Phillips I must conclude. I do not think I should have allowed these notions to have escaped from me had I not been led unawares, and without previous consideration, by the circumstances of the evening on which THE 8HAD0W OF A SPECULATION. 197 I had to appear suddenly * and occupy the place of another. Now that I have put them on paper, I feel that I ought to have kept them much longer for study, consideration, and perhaps final rejection ; and it is only because they are sure to go abroad in one way or another, in consequence of their utterance on that evening, that I give them a shape, if shape it may be called, in this rei)ly to your in([uiry. One thing is certain, that any hypothetical view of radiation which is likely to be received or ret;uned as satisfactory must not much longer comprehend alone certain phenomena of light, but must include those of heat and of actinic intluence also, and even the conjoined phenomena of sensible heat and chemical power produced by them. In this respect a view which is in some degree founded upon the ordinary forces of matter may perhaps find a little consideration amongst the other views that will jirobably arise. I think it likely that I have made many mistakes in the preceding pages, for even to myself my ideas on this point appear only as the shadow of a speculation, or as one of those impressions on the mind which are allowable for a time as guides to thought and research. He who labours in exjierimental inquiries knows how numerous these are, and how often their apparent fitness and beauty vanish before the progress and development of real, natural truth. I am, my dear Phillips, Ever truly yours, Roi/al Listitufion, M. Faraday. April 15, 1846. If it be thought that too high ca value has here been set upon a document which its author himself only clauned to be " the shadow of a speculation," let that value be justified out of the * The discourse was to have been dehvered by Wheatstone him- self, who, however, at the last moment, overcome by the shyness from which he siifiered to an almost morbid degree, quitted the Institution, and left the delivery of the discourse to Faraday. 19s MICHAEL FARADAY. mouth of the man who ei^c^hteen years later enriched the world Avith the mathematical theory of the pro- pagation of electric waves, the late Professor Clerk Maxwell. In 18G4 he published in the Philosophical Transactions a "Dynamical Theory of the Electro- magnetic Field/' in which the following passages occur : — We have therefore reason to believe, from the phenoinena of light and heat, that there is an irthereal medium filling space and permeating bodies capable of being set in inotion, and of transmitting that motion to gross matter, so as to heat it and afteet it in various ways. . . . Hence the parts of tliis medium must be so connected that the motion of one part depends in some waj^ on the motion of the rest ; and at the same time these connections must be capable of a certain kind of elastic yielding, since the communication of motion is not instantaneous, but occupies time. The medium is therefore capable of receiving and storing up two kinds of energy — namely, the "actual" energy depending on the motion of its parts, and "potential" energy, consisting of the work which the medium will do in recovering from displacement in virtue of its elasticity. The propagation of undulations consists in the continual transformation of one of these forms of energy into the other alternately, and at any instant the amount of energy in the whole medium is equ;illy divided, so that half is energy of motion and half is elastic resilience. In order to bring these results within the power of symbolic calculation, I then express them in the form of the general equations of the electromagnetic field. The general equations are next applied to the case of a magnetic disturbance propagated through a non conducting field, and it is shown that the only disturbances which can be so propagated are those Avhich are transverse to the direction ELECTKOMAGNETIC THEORY OF LIGHT. 199 of propagation, and that the velocity of propagation is the velocity v, found from experiments such as those of Weber, which expresses the number of electrostatic units of electricity which are contained in one electromagnetic unit. This velo- city is so nearly that of light, that it seems we have strong reason to conclude that light itself (including radiant heat and other radiations, if any) is an electromagnetic disturbance in the form of waves propagated through the electromagnetic field according to electromagnetic laws. . . . Conducting media are shown to absorb such radiations rapidly, and there- fore to be generally opaque. The conception of the propagation of transverse magnetic disturbances to the exclusion of normal ones is distinctly set forth by Professor Faraday in his " Thoughts on ftay Vibra- tions." The 'electromagnetic theory of light, as j'f'i^oposed by him, is the same in substance as that which I have begun to develop in this paper, ^ except that in 184G there Avere no data to calculate the velocity of propagation. During the rest of this year (1846) and the next Faraday did very little research, though he continued his Royal Institution lectures and his reports for Trinity House. Amongst the latter in 1847 was one on a proposal to light buoys by incandescent electric lamps containing a platinum wire spiral. He was compelled, indeed, to rest by a recurrence of brain troubles, giddiness, and loss of memory. Honours however, continued to be heaped upon him both abroad and at home, as the following extract from Bence Jones shows : — In 1846, for his two great discoveries, the Rumford and the Royal Medals were both awarded to him. This double honour will probably long be unique in the annals of the *■ TJie italics hero are mine. S, P. T, 200 MICHAEL KARA HA V. luiyal Society. In former years he had ahvady received tlie Copley and Royal Medals for his experimental discoveries. As his medals increased it became remarkable that he— who kept his diploma-book, his portraits and letters of scientific men, and everything he had in the most perfect order— seemed to take least care of his most valnable rewards. Tliey were locked up in a box, and mi»;ht have ]iassed for old iron. Probably he thoui:jht, as others di*l afterwards, that their value, if seen, might lead to their loss. BetAveen the t>v en ty- first and tw'onty-second series of '^ Experimental Researehes " nearl}^ three years elapsed. In the autmnn of 184S the matter -which claimed investigation was the pecnliar behavionr ot bismuth in the mametic field. Certain anomalies were observed wdiich were finally traced to tlic crystalline nature of the metal, for it appeared that wdien in that state the crystals themseh^es — to adopt modern phraseology — showed a g^reater magnetic permeability in a direction perpendicular to their planes of cleavage than in any direction parallel to those planes. Hence when a crystalline fragment was hung in a uniform- nuignetic field (Avhere the dianuxgnetic tendenc}^ to move from a strong to a weak region of the field "was eliminated), it tended to point in a determinate direction. Faraday expressed it that the structure of the crystal showed a certain '' axiality," and he regarded these eflects as preseiitinc^ evidence of a " magnecrystallic " force, the law of action being that the lino or axis of magnecrystallic force tended to phice itself parallel to the lines of the magnetic field in "which the crystal was placed. Arsenic, antimony, and other crystalline metals were CRYSTALLINE F(^KCE8. 201 sitiiilarly examined. The subject Avas an intricate one, and there are frequent obscurities in the phrase- ology tentatively adopted for explaining the phe- nomena. In one place Faraday rather pathetically laments his imperfect mathematical knowledge. This seems like an echo of his inability to follow the analytical reasoning of Poisson, who, starting from a hypothesis about the supposed " magnetic fluids " being movable within the particles of a body, supposing that these particles were non-spherical and were symmetrically arranged, had predicted (in 1827) that a portion of such a substance would, when brought into the neighbourhood of a magnet, act differently, according to the different positions in which it might be turned about its centre. But this very inability to follow Poisson's retined analysis gave a new direction to Faraday's thoughts, and caused him to conceive the idea of magnetic permeabilities differing in different directions, an idea which, as Sir Wilham Thomson (the present Lord Kelvin) showed in 1851,* is equally susceptible of mathe- matical treatment by appropriate symbols. Lord Kelvin has also spoken (crp. ciL, p. 484) of the matter as follows : " The singular combination of ■■■ It is light to add that -what, according- to the thuory explained in the text, must be the correct explanation of the peculiar phenomena of magnetic induction depending on magnecrystallic properties was clearly stated in the form of a conjecture hy Faraday in his t\vent\'- second series in the following terms: 'M^r we might suppose that the crystal is a little more apt for magnetic induction, or a httle less apt for diamagnetic induction, in the direction of the magnecrystallic axis than in other directions" (Sir "William Thomson, Philosophical Mr/f/azipc, 1851, or " Papers on Electrostatics and Magnetism," p. 47G). 202 MICHAEL FARADAY. mathematical acuteness -with experimental research and profound ph3^sical speculation which Faraday, though not a 'mathematician,' presented is remark- abl}^ illustrated by his use of the expression ' conduct- ing 'poivev of a m.af/netic vied mvi for lines of force/'' Tyndall has given a succinct summary of these researches — in Avhich also he took a part — from which the following extract must suffice : — And here follows one of those expressions which charac- terise the conceptions of Faraday in regard to force gener- ally : "It appears to me impossible to conceive of the results in any other way than by a mutual reaction of the magnetic force, and the force of the particles of the crystal u])on e:ich other." He proves that the action of the force, though thus molecular, is an action at a distance. He shows that a bismuth crystal can cause a freely-suspended magnetic needle to set parallel to its magnecrystallic axis. Few living men are aware of the difficulty of obtaining results like this, or of the delicacy necessary to their attainment. "But though it thus takes up the character of a force acting at a distance, still it is due to that power of the ]>articles which makes them cohere in regular order and gives the mass its crystalline aggregation, and so often spoken of as acting at insensible distances." Thus he broods over this new force, and looks at it from all points of inspection. Experiment follows experiment, as thought follows thought. He will not relinquish the subject as long as a hope exists of throwing more light upon it. He knows full well the anomalous nature of the conclusion to which his experiments lead him. But experiment to him is final, and he will not shrink from the conclusion. "This force," he says, "appears tome to be very strange and striking in its character. It is not polar, for there is no attraction or repulsion." And then, as if startled by his own utterance, he asks : "What is the nature of the mechanical force which turns the crystal round and makes it affect a magnet?" , . . "I do not MAGNETISM AND CRYSTALLISATION. 203 remember," he continues, "heretofore such a case of force as the present one — Avhere a l>ody is brought into position only without attraction or repulsion." Plucker, the celebrated j;^eometer already mentioned, who pursued experimental physics for many years of his life with singular devotion and success, visited Faraday in those days, and repeated before him his beautiful experiments on magneto- optic action. Faraday repeated and verified Pliicker's observa- tions, and concluded, Avhat he at first seemed to doubt, that Pliickers results and magnecrystallic action had the same origin. At the end of his papers, when he takes a last look along the line of I'esearch, and then turns his eyes to the future, utterances quite as much emotional as scientific escape from Faraday. "I cannot," he says at the end of his first paper on magnecrystallic action, "conclude this series of researches Avithout remarking how rapidly the knowledge of molecular forces grows upon us, and how strikingly every investigation tends to develop more and more their importance and their extreme attraction as an object of study. A few years ago magnetism was to us an occult power, affecting only a few bodies. Now it is found to inliuence all bodies, and to possess the most intimate relations with electricity, heat, chemical action, light, crystallisation, and through it with the forces concerned in cohesion. And we may, in the present state of things, well feel urged to continue in our labours, encouraged by the hope of bringing it into a bond of union with gravity itself." In 1848 Faraday gave five Friday night discourses, three of them on the *'Diamagnetic Condition of Flarne and Gases." In 1849 he gave tAvo, one of them on Pliicker's researches. In 1850 he gave two, one of them being on the electricity of the air, the other on certain conditions of freezing water. He had meanwhile continued to work at magnetism. The twenty-third series dealt with the 204 MICHAEL FARADAY. supposed diamagnetic polarity. It incidentally dis- cussed the distortion produced in a magnetic field by a mass of copper in motion across it. The twenty- fourth series was on the possible relation of gravity to electricity. The paper concludes with the words : " Here end my trials for the present. The results are negative. They do not shake my strong feeling of the existence of a relation between gravity and electricity, though they give no proof that such a relation exists." The next series (the twenty-fifth) was on the *' Non-expansion of Gases by Magnetic Force " and on the " Magnetic Characters of Oxygen [Avhich he had found to be highly magnetic], Nitrogen, and Space." He had found that magnetically sub- stances must be classed either along with iron and the materials that point axially, or else with bismuth and those that point equatorially, in the magnetic field. The best vacuum he could procure he regarded as the zero of these tests ; but before adopting it as such, he verified by experiment that even in a vacuum a magnetic body still tends from weaker to stronger places in the magnetic field ; Avhile diamag- netic bodies tend from stronger to weaker. He then says Ave must consider the magnetic character and relation of sjKtce free from any material substance. " Mere space cannot act as matter acts, even though the utmost latitude be allowed to the hypothesis of an ether." He then proceeds as follows : — Now that the true zero is obtained, and the great variety of material subj^^tances satisfactorily divided into two general classes, it appears to me that we want another name for the magnetic class, that we may avoid confusion. The word MORE NKW WOEDS. 205 magnetic ought to be general, and include all the phenom- ena and effects produced by that power. But then a word for the subdivision opposed to the diamagnetic cla.ss is necessary. As the language of this branch of science may soon require general and careful changes, I, assisted by a kind friend, have thought that a word — not selected with particular care — might be provisionally useful ; and as the magnetism of iron, nickel, and cobalt when in the magnetic field is like that of the earth as a whole, so that when rendered active they place themselves parallel to its axes or lines of magnetic force, I have supposed that they and their similars (includ- ing oxygen now) might be called paramagnetic bodies, giving the following division : — (.diamagnetic. The " kind friend" alluded to was Whewell, as the following letter shows : — [Hev. W. Whewell to M. Faraday.] July, 1850. I am always glad to hear of your wanting new ivords, because the want shows that you are pursuing new thoughts — and your new thoughts are worth something — but I always feel also how difficult it is for one who has not pursued the train of thought to suggest the right word. There are so many relations involved in a new discovery, and the word ought not glaringly to violate any of them. The purists would certainly object to the opposition, or co-ordination, of ferro- magnetic and diamagnetic, not only on account of the want of symmetry in the relation oi ferro and dia, but also because the one is Latin and the other Greek. . . . Hence it would appear that the two classes of magnetic bodies are those which place their length ■parallel, or according, to the terrestrial magnetic lines, and those which place their length transverse to such lines. Keeping the preposition dia for the latter, the preposition para, or ana, might be used for the former. Perhaps pjara would be best, as the word parallel, in which it is involved, would be a technical memory for it. ... I 206 MICHAEL FARADAY. rejoice to hear that you have new views of discovery opening to you. I always rejoice to hail the light of such Avhen they dawn upon you. The twenty-sixth series of researches opened with a consideration of magnetic " conducting power," or permeability as we should now^ term it, and then branched oti' into a lengthy discussion of atmospheric magnetism. The subject was continued through the twenty - seventh series, which was completed in November, 1850. The gist of this is summed up in one of his letters to Schonbein : — Roj^al Institution, November 19, 1850. Mv PEAR ScHoXBErx,— I Avish I could talk with you, instead of being obliged to use pen and paper. I have fifty matters to speak about, but either they are too trifling for writing, or too important, for what can one discuss or say in a letter ? ... By the bye, I have been working with the oxygen of the air also. You remember that three years ago I distinguished it as a magnetic gas in ray paper on the diiunagnetism of flame and gases founded on Bancalari's experiment. Now I find in it the cause of all the annual and diurnal, and many of the irregular, variations in the terrestrial magnetism. The observations made at Hobarton, Toronto, Greenwich, St, Petersburg, "Wasliington, St. Helena, the Cape of (jood Hope, and Singapore, all appear to me to accord with and support my h5q)othesis. I will not pretend to give you an account of it here, for it would require some detail, and I really am weary of the subject. I have sent in three long papers to the lloyal Society, and you shall have copies of them in due time. . . . Ever, my dear Schonbein, most truly yours, M. Faraday. While writing out these researches for the Royal Society, he had been sta3dng in Upper Norwood. He PAl^EKS TO liE LET LOOSE. 207 Avrote thus of himself to Miss Moore at the end of August : — We have taken a little house here on the hill-top, where I have a small room to myself, and have, ever since we came here, been deeply inmiersed in magnetic cogitations. I write, and write, and write, until three pujiers for the Iloyal Society are nearly completed, and I hope that two of them will be good if they justify my hopes, for I have to criticise them again and again before I let them loose. You shall hear of them at some of the Friday evenings. At present 1 must not say more. After writing, I walk out in the evening, hand-in- hand with my dear wife, to enjoy the sunset ; -for to me, who love scenery, of all that I have seen or can see there is none surpasses that of Heaven. A glorious sunset brings with it a thousaml thoughts that delight me." To De la Rive he wrote later as follows : — [M. Faraday to A. <.h la Rive.'] Royal Institution, February 4, 185L My dear De la Eive, — My wife and I were exceedingly sorry to hear of your sad loss. It brought vividly to our remembrance the time when we were at your house, and you, and others with you, made us so welcome. What can we say to these changes but that they show by comparison the vanity of all things under the sun '? I am very glad that you have sjiirits to return to work again, for that is a healthy and proper employment of the mind under such circumstances. With respect to my views and experiments, I do not think that anything shorter than the papers (and they will run to a hundred pages in the "Transactions") will give you possession of the subject, because a great deal depends upon the comparison of observations in dhl'erent parts of the world with the facts obtained by experiment, and with the deduc- tions drawn from them ; but I will try to give you an idea of the root of the matter. You are aware that I use the ])hrase 20s MICHAEL FARADAY. line nr )iivhich it conveys one obtains vitv weil, and I believe without error, a notion of the distribution of the forces about a liar-niaiinet, or between near Hnt ^oles itresenting' a field of equal force, ov in any other case. Xow, if circum- stances be arranged so as to present a field of equal force, which is easily done, as I have shown by the electro-magnet, then if a s]there of iron or nickel be ]ilaced in the field, it inimedi;itely disturbs the direction of the lines of force, fur they are concentrated a\ ithiu the sjiheve. They are, however, not merely concentrated, but co)iforteJ, for the sum of forces in any one section across the field is always equal to the .sum of forces in any other section, and therefore their condensation in the iron or nickel cannot occur without this contortion. Moreover, the contortion is easily shown by using a small needle (one-tenth of an inch k'>ng) to examine the lield, for, :is before the introduction of the s]>here of iron or nickel, it would always take ujt a itosition luirallel to itself. After- wards it varies in position in different jilaces near the sphere. This being understood, let us then suppose the sphere to be raised in temjierature. At a certain temperature it begins to lose its jiower of ati'ecting the lines of magnetic force, and ends by retaining scarcely any. So that as regards the little needle mentioned above, it now stands everywhere parallel to itself Avithin the field of force. This change occurs with iron at a very high temperature, and is passed through within the compass, ajiparently, of a small number of degrees. Witli nickel it occurs at much lower temj^eratures, being atiected by the heat of boiling oil. Xow take another step. Oxygen, as I showed above, three years ago in the Philosophical Magazine for 1S47, vol. xxxi., i)p. 4Ut, 415, 4U), is magnetic in relation to lutrogen and other gases. E. Beccjuerel, without knowing of my results, has confirmed and extended them in his jiaper of last year, and given certain excellent measures. In my pajter of 1847 I showed also that oxygen (like iron and nickel) lost its magnetic power and its ability of being attracted by the ATMOSPHERIC MAGNETISM. 209 mugnet Avhen heated (]i. 417). And I further showed that the temperature.s at Avhich this took place were within the rant;-c of common temperature, for the oxygen of the air — i.e. the air altogetlier — is increased in magnetic power when cooled to O"^ F. (]L 406). Now I mu.st refer you to the pajiers themselves for the (to me) strange results of the incompressibility (magnetically speaking) of oxygen and the inexpansibility of nitrogen and other gases ; for the description of a differential balance by which I can compare gas with gas, or the same gas at ditferent degrees of rarefaction ; for the determination of the true zero, or point between magnetic and diamagnetic bodies ; and for certain views of magnetic conduction and l)ularity. You will there find described certain very delicate experiments upon diamagnetic and very weak magnetic bodies concerning their action on each other in a magnetic held of equal force. The magnetic bodies repel each other, and the diamagnetic bodies repel each other ; but a magnetic and a diamagnetic body attract each other. And these results, combined with the qualities of oxygen as just described, convince me that it is able to deflect the lines of magnetic force passing through it just as iron or nickel is, but to an infinitely smaller amount, and that its power of deflecting the lines varies with its temperature and degree of rarefaction. Then comes in the consideration of the atmosphere, and the manner in which it rises and falls in temperature by the presence and absence of the sun. The place 6i the great warm region nearly in his neighbourhood ; of the two colder regions which grow up and diminish in the northern and southern hemispheres as the sun travels between the tropics; the elfect of the extra warmth of the northern hemisphere over the southern ; the effect of accumulation from the action of preceding months ; the effect of dip and mean declination at each particular station ; the effects that follow from the non- coincidence of magnetic and astronomical conditions of ])olarity, meridians, and so forth ; the results of the distribu- tion of land and water for any given place— for all these and many other things I must refer you to the papers. T could not do them justice in any account that a letter could contain, O 210 MICHAEL FARADAY. and sliOLild run the risk of leading' you into error regarding them. But I may say that, deducing from the experiments and the theory what are the deviations of the magnetic needle at any given station, which may be expected as the mean result of the heating and cooling of the atmosphere for a given season and hour, I find such a general accordance with the results of observations, especially in the direction and generally in the amount for ditFerent seasons of the decimation varia- tion, as to give me the strongest hopes that I have assigned the true physical cause of those variations, and shown the inodus (rpertnidi of their production. And now, my dear de la Eive, I must leave you and run to othei- matters. As soon as I can send you a cofiy of the papers I will do so, and can only say I hope that they will meet with your approbation. With the kindest remembrances to your son. Believe me to be, my dear friend, ever truly yours, M. Fakaday. This hope of explaining the variations of terrestrial magnetism by the magnetic properties of the oxj^gen of the air was destined to be iUusor}^ At that time the cosmical nature of magnetic storms was unknown and unsuspected. To this matter we may well apj^ly Faraday's own words addressed to Tyndall respecting the alleged diamagnetic polarity, and the conflict of views between himself on the one hand and Weber and Tyndall on the other: — '' It is not wonderful that views ditl'er at first. Time Avill gradually sift and shape them. And I believe that we have little idea at present of the importance they may have ten or twenty years hence." In 1851, from July to December, Faraday was actively at work in the laboratory. The results LINES OF MAGNETIC FORCE. 211 constitute the material for the twenty-eighth and twenty-ninth (the last) series of the "Experimental Researches." In these he returned to the subject with which the first series had opened in 1831 : the induction of electric currents by the relative motion of magnets and conducting wires. These two memoirs, together with his Royal Institution lecture of January, 1852, " On the Lines of Magnetic Force," and the paper '* On the Physical Character of the Lines of Magnetic Force" (which he sent to the Philoso'phical Magazine, as containing " so much of a speculative and hypothetical nature "), should be read, and re-read, and read again, by every student of physics. They are reprinted at the end of the third volume of the " Experimental Researches." In the opening of the twenty-eighth memoir he says : — From my earliest experiments on the relation of electricity and magnetism, I have had to think and speak of lines of magnetic force as representations of the magnetic power — not merely in the points of quality and direction, but also in quantity. . . . The direction of these lines about and amongst magnets and electric currents is easily represented and understood in a general manner by the ordinary use of iron filings. A point equally important to the definition of these lines is, that they represent a determinate and unchanging amount of force. Though, therefore, their forms, as they exist between two or more centres or sources of power, may vary very greatly, and also the space through which they may be traced, yet the sum of power contained in any one section of a given portion of the lines is exactly equal to the sum of power in any other section "" of the same lines, ho weaver altered in form ['" This is exactly Stokes's theorem of '* tubes " of force. S. P. T,] 212 MICHAEL FARADAY. or however convergeut or divergent they may be at the yeccucl place. . . , Now, it appears to me that these lines may be employed with great advantage to represent the nature, condition, and comparative amount of the magnetic forces, and that in many cases they have, to the physical reasoner, at least, a superiority over that method Avhich represents the forces as concentrated in centres of action, such as the poles of magnets or needles ; or some other methods, as, for instance, that which considers north or south magnetisms as fluids diffused over the end, or amongst the particles, of a bar. No doubt any of these methods which does not assume too much will, with a faithful application, give true results. And so they all ought to give the same results, as far as they can resjiectively be applied. But some may, by their very nature, be applicable to a far greater extent, and give far more varied results, than others. For, just as either geometry or analysis may be emjiloyed to solve correctly a particular problem, thoui^h one has far more power and capability, generally speaking, than the other; or, just as either the idea of the reflexion of images or that of the reverberation of sounds may be used to represent certain physical forces and conditions, so may the idea of the attractions and repulsions of centres, or that of the disposition of magnetic fluids, or that of lines of force, be applied in the consideration of magnetic phenomena. It is the occasional and more frequent use of the latter which I at present wish to advocate. . . . When the natural truth, and the conventional representation of it, most closely agree, then are Ave most advanced in our knowledge. The emission and aether theories present sucli cases in relation to light. The idea of a fluid or of two fluids is the same for electricity; and there the further idea of a current has been raised, which, indeed, has such hold on the mind as occasion- ally to embarrass the science as respects the true character of the physical agencies, and may be doing so even now to a degree which we at present little sus]iect. The same is the case with the idea of a magnetic tiuid or fluids, or with the assumption of magnetic centres of action of which the resultants are at the poles. 'i'liE FU^^CT10N■S Ot' THi^ .KTHt^U. 'll'i How the magnetic force is transferred through bodies or through space we know not — -whether tlie result is merely action at a distance, as in the case ot gravity, or by some intermediate agency, as in the cases of light, heat, the electric current, and, as I believe, static electric action. The idea of magnetic fluids, as applied by some, or of magnetic centres of ^ action, does not include that of the latter kind of transmission, '' but the idea of lines of force does. Nevertheless, because a particular method of representing the forces does not include such a mode of transmission, the latter is not disproved, and that method of representation which harmonises with it may be the most true to nature. The general conclusion of philosophers seems to be that such cases are by far the most numerous. And for my own part, considering the relation of a vacuum to the magnetic force, and the general character of magnetic phenomena external to the magnet, I am more inclined to the notion that in the transmission of the force there is such an action, external to the magnet, than that the effects are merely attraction and repulsion at a distance. >SWA an action may he a ftinction of the f.ethei\for it is not at all unlikely that if there he an cethe7\ it should have other uses than simply the conveyance of radiations/' He then proceeds to recount the experimental evidence of revolving magnets and loops of wire. Following out the old lines of so moving the parts of the system that the magnetic lines were " cut " by the copper conductors, and connecting the latter with a slow-period galvanometer, to test the resultant in- duction, he found that " the amount of magnetic force" [or fi'ux, as we should nowadays call it] "is determinate for the same lines of force, whatever the distance of the point or plane at which their power is exerted is from the magnet." The convergence or divergence of the lines of force caused, jyer se, no [^ Tlie italics are mino. S. P. T.] 214 MICHAEL FARADAY. difference in their amount. Obliquit}^ of intersection caused no difference, provided the same Hues of force were cut. If a wire was moving in a field of equal intensity, and Avith a uniform motion, then the current produced was proportional to the velocit)'" ot motion. The " quantity of electricity thrown into a current" was, ceteris 2^^?^^^^^-'', "directly as the amount of curves intersected." Within the magnet, I'unning through its substance, existed lines of force of the same nature as those without, exactly equal in ainount to those without, and were, indeed, con- tinuotts with them. The conclusion must logically be that every line of force is a closed circuit. Having thus established the exact quantitative laws of magneto-electric induction, he then advanced to make use of the induced current as a means of investigating the presence, direction, and amount of magnetic forces — in other words, to explore and measure magnetic fields. He constructed revolving rectangles and rings furnished with a shnple commu- tator, to measure inductively the magnetic forces of the earth. Then he employed the induced current to test the constancy of magnets Avhen placed near to other magnets in ways that might affect their power. Next he considers the fields of magnetic force of two or more associated magnets, and notes how their magnetic lines may coalesce when they are so placed as to constitute parts of a common magnetic circuit. The twenty-ninth series is brought to a close by a discussion of the experimental way of delineating lines of magnetic force by means of iron filings. The paper on the " Physical Character of the THE ELECTROTONIC STATE, 215 Lines of Magnetic Force " recapitulated the points established in the twenty-ninth series of " Researches," and emphasis is laid upon the logical necessity that time must be required for their propagation. The physical effects in a magnetic field, as equivalent to a tendency for the magnetic lines to shorten themselves, and to repel one another laterally, are considered, and are contrasted with the effects of parallel electric currents. Commenting on the mutual relation between the directions of an electric current and of its surrounding magnetic lines, he raises the question whether or not they consist in a state of tension of the rether. " Again and again," he says, " the idea of an electrotonic state has been forced on my mind. Such a state would coincide and become identified with that which would then constitute the physical lines of mametic force." Then he traces out the o analogy between a maj^net, with its " sphondyloid " (or spindle-form field) of magnetic lines, and a voltaic battery immersed in water, with its re-entrant lines of flow of circulating current. Incidentally, while discussing the principle of the magnetic circuit, he points out that when a magnet is furnished at its poles with masses of soft iron, it can both receive and retain a higher magnetic charge than it does without them, " for these masses carry on the physical lines of force, and deliver them to a body of surrounding space, which is either widened, and therefore in- creased, in the direction across the lines of force, or shortened in that direction parallel to them, or both ; and both are circumstances which facilitate the conduction from pole to pole." 216 illCHAEL FARADAY. Thus closed, with the exception of two fragmentaiy papers, one on " Physical Lines of Force," and tlic olher on "Some Points in Magnetic Philosophy," in the years LS53 and LS54. respectively, the main lile- Avork of Faraday, his " Fxperiniental Researches." Their effect in revokitionising electric science, if slow, was yet sure. Though the principle of the dynamo was discovered and published in 1831, nearly forty years elapsed before electric-lighting machinery became a commercial product. Though the depend- ence of inductive actions, both electromagnetic and electrostatic, upon the properties of the intervening medium was demonstrated and elaborated in these " Researches," electricians for many years continued to propound theories whicli ignored this fundamental fact. French and German writers continued to publish treatises based on the ancient doctrines of action at a distance, and of imaginary electric and ]nagnetic iiuids. Yon Eoltzn:iann, a typical German of the first rank in science, says that until there came straioht from Eno^land the counter-doctrines amidst which Farada}^ had lived, ''we (in Germany and France) had all more or less iinbibed with our mothers' milk the ideas of magnetic and electric fluids acting direct at a distance." And again, "The theory of Maxwell" — that is, Faraday's theory thrown by Maxwell into mathematical shape — " is so dia- metrically opposed to the ideas which have become customary to us, that we must first cast behind us all our previous views of the nature and operation of electric forces before we can enter into its portals." The divergence of view between Faraday and the NOVELTY OF FARADAY'S VIEWS. 217 Continental electricians is nowhere move clearly stated than by Faraday's great interpreter, Maxwell, in the apolof/ia which he prefixed in 1873 to his '' Treatise on Electricity and Magnetism," wdierein, speaking of the diiferenccs between this work and those recently pubHslied in Germany, he wrote: — One reason of this is that before I began the stud}^ of electiicity I resolved to read no mathematics on the subject till I had fiist read through Faraday's "Experimental Hesearches on Electricity." I was aware that there was ,su})])Osed to l)e a difference between Faraday's way of conceiving i»henoniena and that of the mathematicians. So that neither lie nor they Avere satisfied with each other's language. I had also the conviction that this discre]jancy did not arise from either jiarty being wrong. I was lirst convinced of this by Sir William Thomson [Lord Kehdn], to whose advice and assist- ance, as Avell as to his i)ublished papers, I owe most of what I have learned on this subject. As I proceeded with the study of Faraday, I perceived that his method of conceiving the phenomena was also a mathematical one, though not exhiVjited in the conventional furm of mathematical symbols. I also found that these methods were capable of being expressed in the ordinary mathematical forms, and thus compared with those of the professed mathematicians. For instance, Fiiraday, in Ids mind's 'eye, saw lines of force traversing all space where the mathematicians saw centres of foi-ce attracting at a distance. Faraday saw a medium where they saw nothing but distance. Faraday sought the seat of the phenomena in real actions going on in the medium ; they were satisfied that they had found it in a power of action at a distance impressed on electric fluids. When I had translated what I considered to be Faraday's ideas into a mathematical form, I found that in general the rosnits of the two methods coincided, so that the same phenomena were accounted for and the same laws of action 218 MICHAEL FARADAY. deduced by both methods, but that Faraday's methods resembled those in which we heiiiu witl) the wlioh* and arrive at the parts by analysis, while the ordinary mathematical methods were founded on the principle of beginnini;- with the parts and building ui* the whole by synthesis. I found, also, that several of the most fertile metliods of research discovered by the mathematicians could be ex])rcsscd much better in terms of ideas derived from Faraday than in their ori,i;inal form. The whole theory, for instance, of ])0tential, considered as a quantity which satisfies a certain jtartial differential equation, belongs essentially to the method which I liave called of Faraday. . . . If by anything I have here written I may assist any student in understanding Faraday's modes of thought and expression, I shall regard it as the accomplishment of one of my principal aims ; to conuiuinicate to others the same delight which I have found myself in reading Faraday's " llesearches." Clerk Maxwell may also be credited with the remark that Faraday's work had harl the result of banishing the term " the electric fluid " into the limbo of newspaper science. Faraday's work for Trinity, House continued during these last years of research work. He reported on such subjects as adulteration of white lead, impure oils, Chance's lenses, lighthouse ventila- tion, and fog signals. Two systems of electric arc lighting for lighthouses — one by Watson, ushig batteries, the other by Holmes, using a magneto- electric machine — were examined in 1S58 and 1854, but his report on them was adverse. He " could not put up in a lighthouse what has not been established beforehand, and is only experimental" In 185G he made five reports, in 1857 six, and in 1858 twelve ELECTRIC LIGHT IN LIGHTHOUSES. 219 reports to Trinit}^ House, one of these being on the electric hght at the South Foreland. In 1859 he reported on farther trials in which Duboscq's lamps were used. In 1860 he gave a final report on the practicability and utility of magneto-electric lighting, and expressed the hope it would be applied, as there was now no diflSculty. In 1861 he inspected the machinery as established at the Dungeness light- house. In 1862 he gave no fewer than seventeen reports, visiting Dungeness, Grisnez, and the South Foreland, In 1863 he again visited Dungeness. In 1864 he made twelve reports, and examined the drawings and estimates for establishing the electric light at Portland. His last report was in 1865, upon the St. Bees' light, and he then retired from this service. His Friday night discourses were still continued during these years. In 1855 he gave one on " Ruhmkorff's Induction-coil." In 1856 he gave one on a process for silvering glass, and on finely divided gold. This latter subject, the optical properties of precipitated gold, formed the topic of the Bakerian lecture of that year — his last contribu- tion to the Royal Society. He gave another dis- course on the same subject in 1857, and also one on the conservation of force. In 1856, when investi- gating the crystallisation of water, he discovered the phenomenon of regelation of ice. In virtue of this property two pieces of ice will fi'eeze solidly together under pressure, even when the temperature of the surrounding atmosphere is above the freezing point. This discovery led on the one hand to the 220 MICHAEL FAKAJiAV. explanation of glacier motions ; on the other to im- portant results in thermodynamic theor}'. hi 1859 he gave two disconrses, one on ozone, the other on phosphorescence and iinorescence. He also gave two in ISiiO, on lighthouse illumination by electric light, and on the electric silk-loom. In 18G1 he dis- conrsed on platinum and on Do la Rue's eclipse pho- tographs. The last of his Friday night discourses was given on June 20th, 1N62. It was on Siemens's gas furnaces. He had been down at Swansea watching the furnaces in operation, and now proposed to describe their principle. It was rather a sad occasion, for it was but too evident that his powers were fast waning. Early in the evening he had the misfortune to burn the notes he had prepared, and becauje confused. He concluded Avith a touching personal explanation how with adA^ancing yeai's his memory had failed, and that in justice to others he felt it his duty to retire. At inter-vals he still attempted to Avorlv at research. In 1860 he sent a paper to the Royal Society on the relations of electricity to gravity, but, on the advice of Professor (afterwards Sir George) Stokes, it Avas AvithdraAvn. He had also in contemplation some experiments upon the time required in the propaga- tion of magnetism, and beo'an the construction of a complicated instrument, Avhich Avas never finished. His A^ery last experiment, as recorded in his labora- tory notebook, is of extraordinary interest, as shoAving liOAv his mind Avas still at Avork inquiring into the borderland of possible phenomena. Jt Avas on March 12lh, 18G2. He Avas inquiring into the effect of a HYPOTHESIS AND EXPERIMENT. 221 magnetic field upon a beam of light, which he was observing with a spectroscope to ascertain whether there was any change produced in the refrangibility of the hght. The entry conchides : " Not the shghtest effect on the polarised or unpolarised ray was ob- served." The experiment is of the highest interest in magneto-optics. The effect for which Faraday looked in vain in 18G2 was discovered in 1.S97 by Zeeman. That Faraday should have conceived the existence of this obscure relation between magnetism and light is a striking illustration of the acuteness of mental vision which he brought to bear. Living and working amongst the appliances of his laboratory, letting his thoughts play freely around the pheno- mena, incessantly framing hypotheses to account for the facts, and as incessantly testing his hypotheses by the touchstone of experiment, never hesitating to push to their logical conclusion the ideas suggested by experiment, hoAvever widely they might seem to lead from the accepted modes of thought, he worked on with a scientihc prevision little short of miraculous. His experiments, even those which at the time seemed unsuccessful, in that they yielded no positive result, have proved to be a mine of amazing richness. The volumes of his "Experimental Piesearches" are a veritable treasure-house of science. CHAPTER VI. MIDDLE AND LATER LIFE. Although to avoid discontinuity the account of FaTada3''s researches has in the previous chapter been followed to their close in 1862, we must now return to his middle period of life, when his activities at the Royal Institution were at their zenith. Mention has been made of the serious breakdown of Faraday's health at the close of 1889. Dr. Latham, whom he consulted as to his attacks of giddiness, Avrote to Brande : — Orosvenor Street, December 1, 1831). Dear I^randk,— I have been seeing onr friend Faraday these two or three days, and been looking after his liealth. I trust he has no aihnent more than rest of body and mind will get rid of. But rest is absolutely necessary for him. Indeed, I think it would be hardly prudent for him to lecture again for the present. He looks uj* to his work ; but, in truth, he is not fit, and if he is in^essed he will suddenly break down. When we meet, I will talk the matter over with you. Yours most sincerely, P. M. Latham. The advice was taken. He gave up nearly all research Avork, but tried to go on with Friday night BREAKDOWN OF HEALTH. 223 discourses and afternoon lectures in 1 8 40. Then came a more serious breakdown, and he rested for nearly four years, with the exception of the Christmas lectures in 1841 and a feAV Friday discourses in 1842 and 1843. This illness caused him great distress of mind, mainly due to an idea that the physicians did not understand his condition. When in this state he sometimes set down pencil notes on scraps of paper to relieve his feelings. One such is the following:— Whereas, according to the declaration of that true man of the world Talleyrnnd, the use of language is to conceal the thoughts ; this is to declare in the present instance, Avhen I say lam not able to bear much talking, it means really, and without any mistake, or equivocation, or oblique meaning, or implication, or subterfuge, or omission, that I am not able ; being at present rather weak in the head, and able to work no more. During these times of enforced idleness he used to amuse himself with games of skill, with paper- work, and with visits to the theatre and to the Zoological Gardens. Mrs. Faraday left the following note : — Michael was one of the- earliest members of the Zoological Society, and the Gardens were a great resource to him when overwrouglit and distressed in the head. The animals were a continual source of interest, and Ave, or rather I, used to talk of the time when we should be able to afford a house M'ithin my Avalking distance of the entrance ; for I much feared he could not continue to live in the Institution with the continual calls upon his time and thought ; but he always shrank from the notion of living away from the R. I. His niece, Miss Reid, told how fond he was of seeing acrobats, tumblers, dwarfs and giants; even 224 MICHAEL FARADAY. a Punch and Jiicl}^ show was an unfailing source of deUght, When travelhug in Switzerhxnd, as he did on several occasions, accompanied by Mrs. Faraday and her brother, George Barnard, the artist, he kept a journal, which reveals his simple pleasures and enthusiasms. He is delighted with waterfalls and avalanches, watches the cowherd collecting his cows and the shepherd calling the sheep, which followed him, leaving the goats to straggle. On one such visit (in 1S41), in order that he might not be absent on Sunday from his wife, he Avalked the whole distance from Leukerbad to Thun, over the Gemmi — a distance of 45 miles — in one day. At Interlaken, observing that clout-nail-making was practised as a local industr3^ he wrote : " I love a smith's shop and everything relating to smithery. My father Avas a smith." In 1844 he was well enough to attend the British Association meeting at York. Liebig, who had also been there, wrote to him three months later with some reminiscences. What had struck him most Avas the tendency in England to ignore the more purely scientitic Avorks and to value only those with a "practical" bearing. "In Germany it is quite the contrary. Here, m the eyes of scientific men, no value, or at least but a trifling one, is placed on the practical results. The enrichment of science is alone considere?e>s in her! The breakfast in the little hou^e with Snow Harri>, and Graham, and our being together a-t Bi>hupthorpe, are :^till fresh in my memory. It" Liebig was disposed to underrate the useful apphcations of science, Faradav certainly was not. Though his own research work was carried on with the single aim of scientihc progTess : though he him- self never swerved aside into any branch research that might have }-ielded money: yet he was ever ready to examine, and even to lecture upon, the inventions of others. He accepted for the subjects of his Friday night discourses all sorts of topics — artiticial stone, machinery for pen-making, lithogTaphy, Piuhmkortf's induction coil, a process for silvering mh-rors, and lighthouse illmnination by electric light. His very last lecture was on Siemens's gas-furnaces. He could be just as enthusiastic over the invention of another as over some discovery of his own. AYith respect to his lecture on the EuhmkorH' coil, T3-ndall describes him in a passage which is interestino;, as containino- an epithet smce adopted for another great man for whom Tyndall had less respect than for Faradav : — p •226 MICHAEL FARADAV. I Avell vemeaibei' tlie ccst;isy and sur[iri.sc ct' the (frmul uhl mill, evoked by effect,^ which we should now deem utterly iijsiguitieant. Bence Jones says : — AVheu he brought the discoveries of others before hi:, hearers, one object, and one ahme, seemed to determine all lie said and did, and that was, " without commendation and without censure," to do the utmost that could be cione for the discoverer. In so perfect a charactei' it would be marvellous if there were not some flaw. His persistent ignoring of Sturgeon, and his attribution of the invention of the electromagnet to Moll and Henry, whose work "vvas frankly based on Sturgeon's, is simply inexplicable. He failed to appreciate the greatness of Dalton, and thought him an overrated man. Amid all his overflowing kindliness of heart, Faraday preserved other less obvious traits of char- acter. Any act of injustice or meanness called forth an almost volcanic burst of indignation. Hot flashes of temper, tierce moments of wrath were by no means unknown. But he exercised a most admirable self- control, and a habitual discipline of soul that kept his temper under. Grim and forbidding, and even exact- ing he could show himself to an idle or unfaithful servant. There were those who feared as well as those who loved and admired him. Dr. Gladstone says of him that he was no " model of all the virtues, ' dreadfully uninteresting, and discouraging to those who feel calm perfection out of their reach. "His inner life was a battle, with its wounds as well as its PERSONAL CPlAltACTERlSTlCS. 227 victory." "It is true also," he adds, " that with his great caution and his repugnance to moral evil, he was more disposed to turn away in disgust from an erring companion than to endeavour to reclaim him." For thirty 3^ears Faraday was the f oren lost of lecturers on science in London. From the tirst occasion Avhen, in 1JS23, as Sir Roderick Murchison narrates, he was called upon unexpectedly to act as substitute for Professor Brande at one of his morning lectures at the Royal Institution (then held in the subterranean laboratory), down to the time of his latest appearance as a lecturer in lS(j2, he was without a rival as the exponent of natural science. As no man could achieve and retain such a position without possessing both natural gifts and appropriate training, it is fitting to inquire what were those gifts and what the training which "vvere so happily united in hinr. I was (he said) a very livel}^, imaginative person, and could believe in the Arabian Nights as easily as in the Encyclopaedia ; but facts were iinpuvtant to me, and saved me. I could trust a fact, and always cross-examined an assertion. From the very £rst Faraday had an appreciation of the way in which public lectures should be given. In his notes of Davy's fourth lecture of April, 1812, he wrote : — During the whole of these observations his delivery was easy, his diction elegant, his tone good, and his sentiments sublime. His own first lecture was given in the kitchen of Abbott's house, with home-made appai-atus placed on 228 MICHAEL FARADAY. the kitchen table. To Abbott, after only a few weeks of experience at the Royal Institution, he wrote the letters upon lectures and lecturers, to which allusion was made on p. 15. These show a most remark- ably sound perception of the material and mental furniture requisite for success. From the third and fourth of them are culled the foIloAving excerpts : — The most prominent requisite to a lecturer, though perhaps not really the most important, is a good delivery ; for though to all true philosophers science and nature will have charms innumerable in every dress, yet I ani sorry to say that the generality of mankind cannot accompany us one short hour unless the path is strewed with Howers. In order, therefore, to gain the attention of an audience (and what can be more -disagreeable to a lecturer than the want of it?), it is necessary to jtay sojne attention to the manner of expression. The utterance should not be rapid and hurried, and consequently unintelligible, but slow and deliberate, conveying ideas with ease from the lecturer, and infusing them with clearness and readiness into the minds of the audience. A lecturer should endeavour by all means to obtain a facility of utterance, and the power of clothing his thoughts and ideas in language smooth and harmonious, and at the same time simple and easy. With respect to the action of the lecturer, it is requisite that he should have some, though it does not here bear the importance that it does in other branches of oratory ; for though I know of no species of delivery (divinity excepted) that requires less motion, yet I would Ity no means have a lecturer glued to the table or screwed on the floor. He must by all means appear as a body distinct and separate from the things aroimd him, and must have sonie motion apart from that which they possess. A lecturer should appear easy and collected, undaunted and unconcerned, his thoughts about him, and his mind clear and free for the contemplation and description of his subject. His action should not be hasty and violent, but slow, easy, and QUALIFICATIONS OF A LECTUUEII. 229 niitura], con.sisting principally in changes of the posture of the liDily, ill urdor to avoid the air of .stitfness or sameness that Avriuld otherAvise be unavoidable. His whole behaviour should evince respect for his audience, and he should in no case forget tha.t he is in their jiresence. No accident that does n(.)t interfere Avitli their convenience should disturb his serenity, or cause variation in his behaviour ; he should never, if possible, turn his back on them, but should give them full reason to believe that all his ])Owers have been exeited for their pleasure and instruction. Some lecturers choose to express tlieir thoughts extempora- neously immediately as they occur to the mind, whilst others previously arrange them and draw them forth on paper. But although I alh:)w a lecturer to Avrite out his matter, I do not approve of his reading it— at least, not as he would a quotation or extract. A lecturer should exert his utmost effort to gain comjiletely the mind and attention of his audience, and irresistibly to make them join in his ideas to the end of the subject. He should endeavour to raise their interest at the commencement of the lecture, and liy a series of imperceptible gradations, umioticed by the company, keep it alive as long as the subject demands it. A Hame should be lighted at the commencement, and kept alive with unremitting splendour to the end. For this reason I very much disapprove of breaks in a lecture, and where they can by any means be avoided they should on no account find place. . . . For the same reason— namely, that the audience should not grow tired — I disapprove of long lectures ; one hour is long enough for anyone. Nor should they be allowed to exceed that time. A lecturer falls deeply beneath the dignity of his character when he descends so low as to angle for claps and asks for commendation. Yet have I seen a lecturer even at this point. I have lieard him causelessly condemn his own powers. I have heard him dAvell for a length of time on the extreme care and niceness that the exfieriment he will make requires. I have heard Lim ho]ie for indulgence when no indulgence was wanted, and I have even heard him declare that the experi- 230 MICHAEL FARADAY. inent now made cannot fail, from its l>caiity, its correctness, and its application, to gain the approbation of all. ... 1 would wish apologies to be made as seldom as possible, and generally only Avhen the inconvenience extends to the com])any. I have several times seen the attention of by far the greater ])art of the audience called to an error l>y the apology that followed it. 'Tis w^ell, too, Avhen the lecturer has the ready wit and the ])resence of mind to turn any casual circumstance to an illus- tration of his subject. Any ]tarticu]ar circnmstauce that has become table-talk for the town, any local advantages or dis- advantages, any trivial circumstance that may arise in com- liany, give great force to illustrations ajitly drawn from them, and ])lease the audience highly, as they conceive they i)erfectly understand them. Apt experiments (to Avhich I have liefore referred) ought to be explained by satisfactory theory, or otherwise Ave merely ])atch an old coat vi'ith new cloth, and the whole [hole] becomes Avorse. If a satisfactory theory can be given, it ought to be given. If we doubt a received opinion, let us not leave the doubt unnoticed and affirm our own ideas, but state it clearly, and lay down also onr objections. If the scientific world is divided in opinion, state both sides of the question, and let each one judge for himself hy noticing the most striking and forcible circumstances on each side. Then, and then only, shall we do justice to the subject, please the audience, and satisfy our honour, the honour of a i)hilosoplier. One wdio already had set before himself such bi^h ideals could not fail at least to attempt to fulfil them. Accordmgly, when in ISIG he began to lecture to the City Philosophical Society, he Leoan to attend an evening class on elocution conducted by Mr. B. H. Smart, though the pinch of poverty made it difficult to him to afford the needful fees. Again, in 1823, previous to taking part in Brando's laborator}^ lectures, USE OF CRITICISM. 231 he took private lessons in elocution from Smart, at the rate of half-a-guinea a lesson. After 1827, when he was beginning his regular courses of lectures in the theatre, he often used to get Mr. Smart to attend in order to criticise his delivery. Amongst the rules found in his manuscript notes were the following : — Never to repeat a phrase. Never to go back to amend. If at a loss for a word, not to ch-cli-cli or eh-eh-eh, Imt to stop and wait for it. It soon comes, and the bad habits are broken and fluency soon acquired. Never doubt a correction given to me by another. His niece, Miss Rcid, who lived from 1830 to 1840 at the Institution with the Faradays, gave the following amongst her recollections : — ^[r. Magrath used to come regularly to the morning lec- tures, for the sole purpose of noting down for him any faults of delivery or defective pronunciation that could be detected. The list was always received with thanks ; although his cor- rections were not uniformly adopted, he Avas encouraged to continue his remarks with perfect freedom. In early days he always lectured with a card before liim with SUno Avritten upon it in distinct characters. Sometimes he would overlook it and become too rapid ; in this case, Anderson had orders to ])lace the card before him. Sometimes he had the word Time on a card brought forward when the hour was nearly exjjired. In spite of his recourse to aids in acquiring elocu- tionary excellence, his own style remained simple and unspoiled. " His manner," says Bence Jones, " Avas so natural, that the thought of any art in his lecturing never occurred to anyone. For his Friday 232 MICHAEL FAltADAY. discourses, and for his other set lectures in tlie tlieatre, he always made ample preparation beforehand. His matter Avas always over-abundant. And, if his ex- periments were always successful, this was not solely attributable to his exceeding skill of hand. Ynr, un- rivalled as he was ns a manipulator, in the cases in which he attempted to shoAv complicated or ditHcult experiments, that which was to be shown Avas always well rehearsed beforehand in the laboratory. He was exceedingly particular about small and simple illus- trations. He never merely told his hearers about an experiment, but showed it to them, however simple and well known it might be. To a young lecturer he once remarked ; ' If I said to my audience, "This stone will fall to the ground if I open my hand," I should open my hand and let it fall. Take nothing for granted as known; inform the eye at the same time as you address the ear.' He always endeavoured at the outset to put himself en ra/p2')ort with his audience by introducing his subject on its most familiar side, and then leading on to that which Avas less familiar. Jjefore the audience became aAvare of any transition, they Arerc already assimilating ncAv facts Avhich Avere thus brought Avithin their range. Nor did he stay his dis- ct)urse upon the enunciation <»f facts merely. Alnjost invariably, as his allotted hour drcAv toAvards its close, he gave I'ein t(.t his imagination. Those Avdio had Ijegun Avith him on the loAver plane of simple facts and their correlations Avere bidden to consider the Avider bearings of scientitic principles and their relations to philosoph}', to life, or to ethics, ^^■hile he never ^nvvQf] a perriration, nor draggof] i^ a (piotation from A,S LKCTIJltEJI. Zoo the poets, his own scientific inspiratitjn, as he outlined some Avirle-sweeping' speculation or suggestion for future discoveries, amply supplied the Htting iinale. If the rush of his ideas might sometimes be compared to tearing through a jungle, it at least never degen- erated into sermonisinir ; and never, save "vvhen he ■was physically ill, failed to arouse an enthusiastic glow of response in his hearers. ' No attentive listener,' says Mrs. Crosse, 'ever came away from one of Fara- day's lectures wuthout having the limits of his spiritual vision enlarged, or without feeling that his imagination had been stimulated to something beyond the mere expression of physical facts.' " He was not one who let himself dwell in illusions. When he did Avell he was perfectly conscious of the fact, and enjoyed a modest satisfaction. If he had failed of his best, he was conscious too of that. His deliberate act in giving up all other lectures at the time when his brain-troubles were gaining upon him, while retaining the Christmas lectures to juveniles, was thoroughly characteristic. Of one of his earlier courses of lectures he himself made — about 1(S32 — the following note : — The eight lectures on the operations of the laboratory at the Koyal Institution, April, T828, wtre not to uiy minrl. There does not appear to be that opportunity of fixing the attention of the audience by a single clear, consistent, and connected chain of reasoning which occurs when a principle (sic) or one particular application is made. . . . I do not think the operations of the laboratory can be rendered useful and popular in lectures. . . . The matter of these same lectures was, however, the basis of his book on Chemical Manipulation 2;i4 MICHAEL FARADAV. published in 1827. It went througli three editions, and was reprinted in America. But in 1838 he decHned to let a new edition be issued, as he con- sidered the work out of date. Besides the note quoted above from the Faraday MS. occurs the following : — The six juvenile lectures given Christmas, 1827, were just what they ought to have been, both in matter and manner; but it would not answer to give an extended course in the same spirit. Nineteen times did Faraday give the Christmas lectures. Those on the Chemistry of a Candle were given more than once ; and were the last he gave, in LSflO. They have been pul:)lished, as were those on tbc Forces of Nature. The lectures on Metals he was urged to publish, but declined in the following terms : — Pioyal Institution, January 3, 1850. Dear Sir, — ^lany thanks to both you and Mr. Bentley. jNIr. ilurray made me an unlimited offer like that of Mr. Bentley's many years ago, but for the reasons I am aljout to give you I had to refuse his kindness. He proposed to take them by shorthand, and so save me trouble, but I kneAv that would be a thorough failure ; even if I cared to give time to the revision of the MS., still the lectures without the ex])eri- ments and the vivacity of speaking wuuld fall far behind tho.^e in the lecture-room as to effect. And then I do not desire to give time to them, for money is no temptation to me. In fact, I have always lovtd science more than money ; and because my occupation is almost entirely personal I cannot alford to get rich. Again thanking you and Mr. Bentley, I remain. Very truly yours, M. Faraday. AX IXSPIRED CHILD. 235 Of his lectures Lady Pollock wrote : — He would play Avith his suliject now and then, but very delicately ; his sport was only ju.st enough to enliven the attention. He never suffered an experiment to allure him away from his theme. Every touch of his hand was a true illustration of his argument. . . . But his meaning was sometimes beyond the conception of those whom he addressed. ^yhen, however, he lectured to children he was careful to be perfectly distinct, and never allowed his ideas to outrun their intelligence. He took great delight in talking to them, and easily won their confidence. The vivacity of his mnuner iind of his countenance, and his pleasant laugh, the f)-ankness of his whole bearing, attracted them to him. They felt as if he belonged to them ; and indeed he sometimes, in his joyous enthusiasm, a]tpeared like an inspired child. . . . His quick sympathies put him so closely in relation with the child that he saw with the boy's ncAv wonder, and looked, and most likely felt for the moment, as if he had never seen the thing before. Quick feelings, quick movement, quick thought, vividness of exi)ression and of perception, belonged to him. He came across you like a flash of light, and he seemed to leave some of his light with you. His presence was always stimulating. — St. PauFs Mugazine^ June, 1870. A writer in the British Qiiarterljf Reviev) says : — He had the art of making philoso])hy charming, and this was due in no little measure to the fact that to grey-headed wisdom he united wonderful juvenility of spirit. . . . Hilariously boyish upon occasion he could be, and those wlio knew him best knew he Avas never more at home, that he never seemed so pleased, as when making an old boy of him- self, as he wns wont to say, lecturing before a juvenile audience at Christmas. Caroline Fox (in " Memories of Old Friends "), under date June 13th, 1851, wrote in her journal ; — 2'4{) :\ii(ii.\EL fai:ai).\v. We Avent to Faraday's lerturu on "Ozone." He tried the \ariuu.s methods of making ozone \vhich Schunbein liad already lierformed in our kitchen, and he did them brilliarjtly. He was entirely at his ease, botli witii his audience and his rliemical ajiparatus. In the diary of H. Crabb Robinson is an apjirecia- ti'.tn of Faraday of some interest : — May 8th, 1S40. . . . Attended Carlyles second lecture. It gave great satisfaction, for it had uncommon thoughts and was delivered with unusual animation. ... In the evening heard a lecture by Faraday. What a contrast to Carlyle ! A perfect exiieriatentalist with an intellect so clear. Within liis sj)here ti7i nomo cnnipito. Many references to Faraday's lectures occur in the life of Sir Richard Owen ^published 1S04}, chiefly ex- tracted from ]\[rs. Owen's diary. Two or three extracts must suffice : — ]8:i!), -Ian. sth. At eight o'clock with It. to the iloyai Institution to liear Faraday lecture on electricity, galvanism, and the electric eel. Faraday i.s the Ix^aic ideal of a popular lectui'er. l>^4-"t, Jan. 3]. To Faraday's lecture at the Koyal Institu- tion. The largest crowd I have ever seen there. Many gentlemen were obliged to come into the ladies' gallery, as they could not get seats elsewhere. After an exceedingly interesting lecture, Farad;iy said he had a few remarks to make on some new reform laws for the In.-^titution. These remarks Avere admirably made, and no one could feel ofi'ended, although it was a direct attack on those gentlemen who helped to render the ladies very uncomfortable, sometimes hy filling seats, and often front seats, in the part intended only for ladies. Wearing a hat in the library was one of the delin- quencies, likewise sitting in the seats reserved for the directors, who were oblig-ed bv their office and duties to be last in. Mr. ROYAL INSTITUTION LECTURES. 237 Faraday also remarked that the formation of two currents caused by certain gentlemen rushing upstairs the instant the lecture Avas over to fetch their lady friends Avas not conducive to the comfort of those coming downstairs. Eve.rything taken very well. 1849, May :>8th. AVith R. to lloyal Institution. AVe got there just before three, and there was a crowded audience as usual to hear Faraday's lecture. The poor man entered and attem](ted to speak, but he was suffering from inflammation or excessive irritation of the larynx, and after some painful efforts to speak, a general cry arose of '* Postpone," and sotneone, appaiently in authority, made a short speech from the gallery. Mr. Faraday still wished to try and force his voice, saying he was well aware of the difficulty of getting back the carriages, etc., before the time for the lecture had elapsed, to say nothing of the disappointment to some ; but every moment the cry increased. *' No, no ; you are too valuable to be allowed to injure yourself. Postpone, postpone." Poor Faraday was (]uite overcome. The interrupted lecture was resumed after a fort- night's interval; and he made up the full number of lectures Ly giving two extra discoiu'ses, at one (.)f wliich the Prince Consort Avas present. At another lecture [in 1856] Faraday explained the magnet and strength of attraction. He made us all laugh heartily ; and when he threw a coalscuttle full of coals, a poker, and a pair of tongs at the great magnet, and they stuck there, the theatre echoed with shouts of laughter. His friend De la Rive testified in striking terms to Faraday's power as a speaker. Nothing can give a notion of the charm wliich he imparted to these improvised lectures, in which he knew how to combine animated, and often eloquent, language with a judgment and art in his experiments which added t<.) the '2SH MiCHAEr. FAUADAY. clearness and elegance of his exposition. He exerted an actual fascination upon his auditors ; and when, after having initiated them into the mysteries of science, he terminated his lecture, as he was in the habit of doing, hy rising into regions far alcove matter, space, and time, the emotion which he experienced did not fail to communicate itself to those who listened to him, and their enthusiasm had no longer any iKjunds. FarafL\y remained all his life a keen observer of other lecturers. Visiting France in 1845, he went to licar Araf>:o i^ive an astronomical lecture. " He delivered it in an admirable manner to a crowded audience," was his connnent. To the Secretary of the Institution, who in LS4G consulted him regarding evening lectures, he said: I see no objection to evening lectures if you can find a tit man to give them. As to jjopular lectures (which at the same time are to be fespectahlt^. and soiuid), none are more difficult to find. Lectures which renlli/ teacii will never be popidar ; lecturijs which are jjopular will never really teach. They knt.iw little of the mattt-r who think science is more easily to be taught or learned than A B C ; and yet who ever learned his A E C without pain and trouble? >Still, lectures can (generally) inform the mind, and show forth to the attentive man what he really has to learn, and in their way are very useful, esjjecially to the i)ublic. I think they might be useful to us now, even if they only gave an answer to those who, judgiijg by their own earnest desire to learn, think much of them. As to agricultural chemistiy, it is no doubt an excellent and a popular subject, but I rather suspect that thosh; who know lea^t of it think thnt most is known about it. His fondness lor illustrating obscure points in his lectures Ijy models has been more than once alluded to. He would improvise these out of wood, pa2Jer, USE OF MitliELS AXI) CARDS. 2:in Avire, or even out of turnips or potatoes, with much dexterit}' of hand. In one of his iinpubhshed manuscripts, dating about 1826, deahng with the then recently discovered phenomena of electro- magnetism, occurs the following note: — It is best for illustration to have a innJel of the constant li'isitinn which tlic iieeillc takes across the wire : le v<>i.la (Fig. 1^1). Man}' such simple models were used in his lectures. He leaned upon them to aid his defecri\'e memory; but they helped his audience quite as nuich as they aided him. Reference was made on p. 7 to his use of cards, on wdiich to jot down notes of thoughts that occurred to him. One such runs as follows ; — Ren:ember to do one thing at once. Also to finish a thing. Also to do a little if I could not do iiiucJi. Pique about mathematics in chemists, and resolution to support the character of experiment — as better for the mass. Hence origin of the title Exp. resenrchts. Influence of authority. Davy and difficulty of steering between self-siifflcltncy and dependance (.s/c) on ntliers. 240 MICHAEL KAIIADAV. Aim ;it lii;j;li lliiii^^s, ln.it nuL iirL'siiiii|itiiinisly. Endcav(.mr In .succeed -uxpLw.;t iioL tn sii(;(;(;e*l. Cr/'firis/-' (Die's own view in every way ljy ex|ie)'iiiiriit.- if po.s-iibic, leave iin i>l>jcelinii to l>e piil liy otiieis. J^\ir;t(ljiy'.s ontlmsiiisiii ji!joii(, oxporinioiiljil re- searches was at tinios iinrestraincrl, and always contagions. Dnnias dcsci-iljos how Faraday repealed for hini the ex})eriniental dcinonstj'ation of the action of niaij^Jietisra on hght. Having corrie to the iinal cxi)crinient, Faraday rubbed his hands excitedly, while his eyes ht up with tire, and his animated countenance told the passionate feelings whicli he Ijrought to the discovery of scientitic truth. On another occasion Plticker, of Borni, then the date of 18^7, when Henry visited Euro2Je. FKEEiJOM OF SPECULATIOX. 24? L Henrj' loved to dwell on the houris tliat he and Bache had s^ient in h'aradays society. I shall never forget Henry's account of his visit to King's College, London, where Faraday, Wheatstone, Daniell, and he had met to try and evolve the electric spark from the thermopile. Each in turn attempted it and failed. Then came Henry's turn. He succeeded, calling in the aid of his discovery of the efte(;t of a long interpolar wire wrapped around a piece of soft iron. Faraday became as wild as a boy, and, jumping np, shouted : " Hurrah for the Yankee experiment ! " The following inemoranduiii was found on a slip of paper in Faraday's " research drawer " : — THE FOITII DEGUEES. The disc(>verer of a fact. y The reconciling of it to known principles. Discovery of a fact not reconcilable. He wdio refers all to still more general jirinciples. M. F. Faraday's mind was of a very individnal turn; he conld not walk along the beaten tracks, but must pursue truth Avherever it led him. His dogged tenacity for exact fact was accompanied by a perfect fearlessness of speculation. He Avould throw over- board without hesitation the most deeply-rooted notions if experimental evidence pointed to newer ideas. He had learned to doubt the idea of j^oles ; so he outgrew the idea of atoms, Avhich he considered an arbitrary conception. Many Avho heard his bold speculations and his free coinage ot new terms deemed him vague and loose in thought. Nothing could be more untrue. He let his mind play freely about the facts; he framed thousands of hypotheses, 242 mk;makl kahaimv. only U> lot thciii go by if Uif^y wore not sijf>fK>rtod by facts. "Ho is the wisest philoHf>j>bor," ho said in a locture on the natnro of n)attor, "who holds \uh theory with somo donbt> — who is ahio to [jroportion his judgment and oonlidonoo U> tho valuo of tho evidonoo sot hoforo liim, taking a fact for a fact and a siippoKition for a Hnp[)OKitif>n, as Trmofi as possible keeping his mind free irom all source of pn^jufliee; or, where he cannot do tfiis (as in the ease of a theory), romemhering tJjat such a source is there." In one of his later experimental roKeareJios he wrote : — An an oxperirncntfiJiHt, J feel bound to let exp'-rirnent ^^uide rne into any train of thoijf<}»t whiclj it may justify ; being Hiii'i'^iicA thai experiment, like analyHix, niuwt leiJ'l to strict truth if rightly \uii:v\)V*-Xf'A -^ and believing jjIho that it iH in itH nuime far njore suggeHiive of new trainH of thought and new conditionn of natural power. Perhaps it was this very freedrnn of tliooght which debarred hirn from onh'sting other men as collaborators in his reHoarcljos, IJi^ one assistant for thirty years, Sergeant Anderson, was indeed in- valuable to him for bis quality of implicit obcrlienee. Other helpers in the lal^oratory he ha^l none. Ap- parently he found hix researches to }>e of too indi- vidual a eharaeter t/> pennit him t/j deputise; any part of his work, lie wa« never satiwfiefl when told al>f»ut another's experiment; he rniwt porforrrj it for hUumK, Often a discovery arose from some chari';^^ or trivial incident of an otharwim unsuccessful experiment. The power oi ''kt^^al vision," which Tyndall has so strongly emphasised, was a j;rimo factor in his WHY XO SUCCESSOR. -43 successes. That power could not be delegated to any uiere assistant. ^lany times did outsiders approach him. thinking to bring new facts to his notice: never, save on the solitary occasion when a Mr. William Jenkin drew his attention to the "■ extra-current " spark seen on the breaking of an electric circuit, did such novelties turn out to be really new. Alleged discoveries thus brought to him merely plagued him. He thought that anyone who had the wit to observe anv really new phenomenon woidd be the person best cpialitied to work it out. His method was to work on alone, dwelling amidst his experiuients until the mind, familiarising itself Avith the facts, was ready to suggest their correlations. It was sometimes urged against him as a complaint that he never took up any younger man to train him as his successor, even as Pavy had taken up himself and trained him in scientitic work. One of the miscellaneous nines, found after his death. throws some liirht on this : — o '^ It puzzles me greatly to know what makes the successful philosopher. Is it industry and perseverance with a moderate proportion of good sense and intelligence? Is nut a modest assurance or earnestness a requisite ' Do not many fnil be- cause they look rather to tlic renown to be acquired than to the i>ure acquisition of knowledge, and the delight which the contented niind hns in acquiring it for its own sake? lam sure I have seen many who would have been good and success tul pursuers of science, and have gained themselves a high name, but that it was the name and the reward they were :dw;iy-^ looking forward to— the reward of the world's jiraise. In ^uch there is always a shade of envy or regret over their minds, and I cannot imagine a man making discoveries iu science under these feelings. , As to Cieuius and its power, 244 MICHAEL FARADAY. there iiiuy l>c cawcs ; I sii]i|)usc there are. 1 have looked lon.i;' and often for a .renins for our Laboratory, but have never found one. TUit I Jiave seen nmuy :vho would, I think, if they had submitted tlieniselves to a .sound self-ap])lied di.scii)line of mind, have become suci-essful experimental Philosopliers. To 1 )r. liecker lie Avi'oto : I was never able to make a fact my own without seein;j,- it ; and the descriptions of the best works altogether failed to convey to my mind such a knoAvledge of things as to allow myself to form a judgment upon them. Jt was so with ?k'?" things. If Grove, or Wheatstone, or Gassiot, or any other told me a new fact, and wanted my opinion either of its value, or the cause, or the evidence it could give on any subject, I never could say anything until I had seen the fact. For the same reason I never could work, as some Professors do most extensively, liy students or pupils. All the Avork had to be my own. Of Faruday's social life and suiToundings during his meridional and later period nnicli might be Avritten. After his great researches of 1831 to 1836 scientific honours flowed in freely u})on him, especially from foreign academies and universities; and the fanje he Avon at home Avould haA^e brought him, had he been so minded, an ample professional fortune and all tlie artificial amenities of Society Avhich follow the successful money-maker. From all such mundane " success " he cut himself off' when in 1881 he decided to altandon professional fee-earning, and to devote liiiuself to the advancement of science. Probably the tf-'uets of the religious body to Avhich he belonged Avere a leading factor in coujpelling this decision. Not having laid upon hiiu the necessity of providing for a family, and accustomed to live in an unostenta- INCOME AND EXPENDITURE. 245 tious style, he could contemplate the future without anxiety. With his pension, his Woolwich lectures, and his Trinity House appointment, Faraday was in no sense poor, though his Roj^al Institution professor- ship never brought him so much as £300 a year until after he was over sixty years of age ; but on the other hand, his private charities were very numerous. How much of his income was spent in that way can never be known ; for the very privacy of his deeds of kind- ness prevented any record from being kept. Certain it is that his gifts to the aged poor and sick must have amounted to several hundreds of pounds a year ; for while his income for many years must have averaged at least £1,000 or £1,100, and his domestic expendi- ture could not have inuch exceeded half that sum, he does not seem to have attempted to save anything. Nor did he grudge time or strength to do kindly charitable acts in visiting the sick. From about the year 1834 he resolutely declined invitations to dinners and such social gaieties ; not, as some averred, from any religious asceticism, but that he might the more unrestrainedly devote himself to his researches. " If," says Mrs. Crosse, " Babbage, Wheatstone, Grove, Owen, Tyndall, and a host of other distinguished scientists, were to be met very generally in the society of the day, there was one man Avho was very conspicuous by his absence — this was Faraday ! His biographers say that in earlier years he occasionally accepted Lady /iJavy's invitations to dinner : but I never heard of his going anywhere, ex- cept in obedience to the commands of royalty." He did indeed occasionally dine quietly with Sir Robert & i^4G Michael KAKAi)AV. Peel or Envl Russcli ; and of the Icn^^ public (llniiers he attended, he enjoyed most the annual banquet ut' the Ro3^al Academy of Arts. Faraday does not, however, a[)pear to have had . any very direct rehxtions with the world of art. Once he was consulted by Lord John Russell as to the rejnoval of Raphael's cartoons from Hampton Court to the National ( Jallcry. His advice was adverse, on account of the penetrating power of dust. Though a sufficiently good draughtsman to prepare his own drawings, lie had little or no knowledge of the technicalities of painting. Yet his sensitive and enthusiastic temperament had nmch in common with that of the artist, and he enjoyed nuisic, especially good music, greatly. In early life he played the Hute and knew many songs by heart. He took bass parts in concerted singing, and is said to liave sung correctly in time and tunc. In his circle of acquaintanceship Avcrc numbered several painters of eminence — Turner, ]jandsccr, and Stan field. His brother-in-law, Mr. (ieorge J:{arnard, the late well- known water-colour artist, has written the following note : — - My iirst ami many following Hkctf^liiiig trips wltc inado with Faraday and his wife. Storms excited his admiration at all tinK's, and he was never tired of looking into the heavens. He s:iid to me once, "i wonder you artists don't study the light and colour in the shy jnore, and tiy nioi-e for eflfect." I think this tiuality in Turner's drawings made him admire them so much. He made Turner's acijuaintanee at Hullmander.s, and afterwards often had applications from him for chemical information about jtigments. Faraday always impressed u|)on Turner and other artists the great necessity there Avas t(j SCLEXCE, LITEUATUllE. AXD AUT. 247 experiment i>H' tlieiii>elve.s, putting washes and tints of all their pigments in the bright sunlight, covering up on^^ half, and noticing the effect of light and gases on the other. . . . Faraday did not tish at all during these ci.-untry tri[ts, but just rambled about geologising or botanising. Earlier iu his career, Faraday and his brother-in- law used to enjoy conversaziones of artists, actors, and musicians at Hulhnandel's. Sometimes they went up the river m HtiUmandel's eight-oar boat, camping gipsy- wise on the banks for dinner, and enjoying the singing of Sigxior Garcia and his wife and of his daughter, afterwards Madame Malibran. From these things, too. he withdrew very largely when he ceased to dine out, though he still liked to hear the opera and to visit the theatre. Curiouslv enough, he seems to have had very little in common with literary men. In the last half of the previous century there had been many intimate relations between the leaders of literature and those of science. The circle Avhich incltided AVatt, Boulton, and Wedgwood included also Priestley and Erasmus Darwin. In our own time the names of Darwin, Huxley, Hooker, and Tyndall are to be found in conjunction with those of Tennyson, Browning, and Jowett. But the biographies of literary men and artists of the period from 1S30 to 1850 bear few references to Faraday. He moved iu his own world, and that a world very much apart from literature or art. In his metht'd of working he was indeed an artist, often feeling his Avay rather than calculating it, and arriving at his conclusions by wdiat seemed insight rather than by any direct process of reasonino-. The discovery of truth conies abotit m 248 MICHAEL FARADAY, iiumy Avays; and if Faraday's method in science was artistic rather than scientific, it was amply jnstitied by the brilhant liarvest of discoveries which it enabled him to reap. As is well known, Faraday never tt)ok out any ])atents for his discoveries : indeed, whenever in his investigations he seemed to come near to the point where they began to possess a marketable A'alue from their application to the industries, lie left them, to pursue his pioneering inquiries in other branches. Ho sought, indeed, for principles rather than for processes, for facts new to science rather than for merchantable inventions. When he had made the discovery of magneto-electric induction — the basis of all modern electric engineering — he carried the re- search to the point of constructing several experi- mental machines, and then abruptly turned away with these inenioraltle Avords : — I have rather, hrtwever, been desirous of discoverinj:,^ new facts and new relations dependent on magneto-electric induc- tion than of exalting tlie force fif those already ftbtained ; being assured that the latter would find their fall deveIo|)nient hereafter. Several times was Faraday known, when asked about the possible utility of some new scientific dis- covery, to quote Franklin's rejoinder : " AVhat is the use of a Ijaby ? " It is narrated of him that on one occjision, at a Trinity House dinner, he and the JJuke of Wellington had a little iriendl}- chat, in the course of which the Duke advised Faraday to give his speculations " a practical turn as i'ar as possible " — " a suggestion," PRACTICAL UTILITIES. 249 said Faraday, who ahvays spoke of the veteran with pleasure, '■' iuU of wei^^-ht, coinino; from such a man.'' Fai-aday ^vas, however, the last to despise the iui- portance of industrial apphcations of science, in his un[.iui^lished manuscripts at the Royal Institution there are some curious references to trials Avhich he made of a meat-canning process, invented aliout 1S48 hy a Mr. i Joldner, of Finsburv. He also had fancies for other domestic applications, includini^ wine-making. He used himself to bind his own note-books. To a ]\Ir. AVoolnough, ^vlio had written a book on the marbling of paper, he wrote a letter saying how much interest he felt in the suljject, " because of its associa- tions with m}' early occupation of bookbinding ; and also because of the very beautiful principles of natural })hilosophy which it involves." He even, on one occasion, jtroduced a home-made pair of boots. His devotion to the practical applications of science is attested by his untiring work for improving the light- liouses of our coast. It is believed that his death was accelerated by a severe cold caught wdion on a visit of lighthouse inspection during stormy weather. Farada)' was never ashamed of the circumstance of his having risen from a humble origin. In his letters he not unfrequentlv alludes to things that reo'iind him of his bookbinding experiences, or of bo\'ish episodes in his father's smithy. Yet he had none of the vulgar pride of ascent wliich too often dogs the path of the self-made man. Severe self- discipline and genuine humility prevented either undue pioclamation or awkward reticence respecting his early life. His elder brother Robert Avas a gas- 250 MHJHAEL FARADAY. litter. Fararlay was not aslianied to help hiin to secure work in his Lraclo, nor to give him the l)eneKt of his scientiiic aid in perfecting ajij^liances for venti- lating by gas-burners. The following characteristic story Avas tohl by Frank Barnard : — Jiobert was tljiougltout life a "warm Irieiid ami admirer of his younger brother, and not a whit envious at .seeing himself passed in the social scale by him. One day he was sitting in the Royal Institution just previous to a lecture by the young and rising lAiilosoplier, when he heard a couple of gentlemen behind him descanting on the iinturrd gifts and rapid rise of the lecturer. The brother — perhaps not fully apprehending the purport of their talk— listened with growing indignation while one of them dilated on the lowness of Faraday's origin. ''Why,' said the sjteaker, "I believe he was a mere shoeblack at one time." Uobert could endure this no longer ; but tuin- ing sharply round he demanded : " Pray, sir, did he ever black your shoes?'' "Oh! dear no, certainly not," replied the gentleman, much abashed at the sudden iu'iuisition into the facts of the case. In 1853 Faraday came before the public in a novel manner— as the exposer of the then rampant charlatanry of table-turning and spirit-rappijig. The Atlievjrv/m for July 2nd contains a long letter from him on table-turning. He experimentally investi- gated the alleged phenomena as produced by three skilful mediums in smvce^^ at the house of a friei.d. His mechanical skill was more than a match, how- ever, for that of the supposed spirits. When the observers assemblerl around the table placed their hands in the orthodox Avay upon the table-top, the taljle turned, apparently without any effort on the part of any one of the part). This was eminently SPJUIT MEDICMS EXPOSED. 251 Siitisfactoi-}- for the spirits. J^ut when Far;idi\y interposed between each hand and the table- top a sinipjle roller-niechanisui which, if any iiidividual in the circle appHed muscular forces tending to tuni it, instantly indicated the fact, the table remained immoA'able. Farada}^ wrote merely describing the facts, and .sa3dng that the test apparatus was now on public view at 122, Regent Street. He ends thus: — I rniLst Ijring this long description to a close. I am a little ashiimed of it, for I think, in the present age, and in this part of the world, it ought not to have been required. Xeverthe- le,-s, I ho]»e it may be usefuh There are ujany whurn I do not expect to convince ; but I may be allowt^d to say that I cannot undertake to answer such ol.jjections as luay be made. 1 stiite Tjiy own convictions as an experimental philosopher, and find it no more necessary to enter into controversy on this point than on any other in science, as the nature of matter, or inertia, or the magnetisation of light, on which I may difi'er from others. The world will decide sooner or later in all such cases, and I have no doubt very soon and coirectly in the present instance. This exposure excited great interest at the time, and there w^as an active correspondence in TIte Times. The spiritualists, instead of appreciating the services to truth rendered by the man of science, railed bitterly at him. Even the refined and noble spirit of Mrs. Browning was so dominated by the superstition of the moment that, as shown by her recently published letters, she denounced Faraday in singularly acrimonious terms, and taunted him lor shallow iiiaterialisni ! What Faraday thought of the liubbtdj evoked hy his action is best learned from a letter 252 MICHAEL FARADAY, ^vhicll he addressed three Aveeks later to his friend Schonbein : — I have not been at work except in turning the tables upon the table-turners, nor should I have done that, but that so many inquiries poured in upon nie, tJiat I thought it better to stop the inpouring flood by letting all know at once what my views and thoughts Avere. "Wluit a Aveak, credulous, incredulous, uulielieving, snperstitious, bold, frightened, what a ridicidous world ours is, as far as concerns the mind of man. How full of inconsistencies, contradictions, nnd absunlitics it is. I declare that, taking the average of many minds that have recently come before me (and ajiart from that .spirit Avhich God has placed in each), and acce|^ting for a moment tliat average as a standard, I should tar prefer the obedience, affections, and instinct of a dog before it. Do not whisper this, however, to others. There is One above who w(^rketli in all things, and who governs even in the midst of that misrule to which the tendencies and i)OAvers of men are so easily perverted. He declined an invitation in 1855 to see mani- festations by the medium Home, saying that he had " lost too much time about such matters already." Nine years later the Brothers Davenport invited him to witness their cabinet " nianifestations." Airain he declined, and added : " I will leave the spirits to find out for themselves how they can move my attention. I am tired of then:i."' In this 3'ear he wrote to The Times respecting the disgraceful and insanitary condition of the river Thames. In Punch of the followdng week appeared a cartoon representing Faraday presenting his card to old Father Thames, wdio rises holding his nose to avoid the stench. AVith increasing;" ao-e the infirmity of loss of memory made itself increasingly felt. He alludes tVeqaently to this in his letters. To one friend who upbraided him gently for not having replied to a letter he sa3^s : "Do you remember that I foig'et ? " T(t another he says he is forgetting how to spell such words as " withhold " and " successful." To Matteucci, in 1849, he bemoans how, after working for six weeks at certain experiments, he found, on looking back to his notes, he had ascertained all the same results eight or nine months before, and had entirely forgotten them! In the same year he wrote to Dr. Percy :— I cannot be on tlie Committee ; I avoid everytliing of that kind, tliat I may keep my stupid liead a little clear. As to being on a Committee and not working, that is worse still. In 1859, in a letter to his niece, Mrs. Deacon, tilled mainly with religious thoughts, he says : " ^Ly worldly faculties are slippiug away day by day. Happy is it for all of us that the true good lies not in them.'* From the journals of AV alter White conies the following anecdote under date December 22nd, 1858:— Mr. Faraday called to enquire on the part of Sir Walter Trevelyan whether a M8. of meteorological ob.servations made in Greenland aa'OuIcI be acceptable. The question answeri'd, 1 expressed my pleasure at seeing him looking so well, and asked him if he Avere Avriting a piqicr for the Ivoyal. He shook his head. "No : I am too old.'' "To*.) old? Why, age iirings Avisdom.^' " Ves, but one may overshoot the wisdom." "You cannot mean that you have outlived your Avisdom ? " "oomething Uke it, for my memory is gone. If 1 make an experiment, I forget before tAvelve hours are over Avhether the result was positive or negative ; and how can I Avrite a paper 2-34 MICHAEL rAKAPAV wliile that is the c;ise .' X(t. 1 must content myself with givin.ii' my lectures to children." From anotlier sonrre wo loaru o\' a liitliorto un- recorded incident which liappened to Mr. -loscph Newton, tor some time an assistant in the Ixoyal ^[int. While arranging some precious material on the Eoyal Institution theatre lectiu'e-table. previous to a lecture on the !Mint and minting operations by Professor Brande. Mr. Xewton noticed an elderl}^ spare, and very plainly-dressed individual Avatching his ujovements. Imagining that this person was a superior messenger ot the Institution, i\[r. NeAvton volunteered some information as to the coinao-e of gold. " I suppose." said the ]\lint employee, "you have been some years at the Royal Institution ^ " '■ Well, yes, I have, a good niany," responded the dilapidated one. '■ 1 hope they treat you prettA' liberally — -1 mean, that they give you a res]-)ectablo ■ screw,' for that is the main point." " Ah 1 1 agree with you there. 1 think that the labourer is worthy of his hire, and 1 shouldn't mind being paid a little better." Mr. Xewton's surprise, on returning to the l\oyal Institution in the evening, to tind that the man Avhoni he had so recently patronised was none other than the illustrious but modest ^lichael Faraday can better be imagined than described. A jirett}' instance, given 'our iuh'soiicc, for Itotli Mrs. atnl l)i'. IVrcy ain*. auxions you should ciMiK' ; and this I know, tiait, the lliin.'j,'s we liavo sci'it would (h'li.'^lit yon, hut. tlu'u I donlit your jiowcrs of rnnuiiii;' aliout. as we do ; aud tli(tu;.,di I Icuow that if time were i;iveii >oii rould eujoy them, yet to press tlie uiatter into a day or two would he a fidlure. V.esides this, aflei' all, (hei'e. is uo jileasnre like tlie trauijuil plea.sures of home, and liri'e - even liere — tlie iU(*meut I lea\'e the tahle, L wisli I were with you IN (H'ti'rr. Oh! what hajipiuess is ours! My ruus into the "worhl in this way only serve to uiake rue esteem that hapjiiness the uiore. I mean to be at houie (ni Saturday uif-ht, liut it may be late, hrst, so do not be sui-prised at that ; for if [ ean, I should like to i;'o on an excui'sion to the I )udley ea,verus, and tliM.t W(tuld take the day Wi'iti,'. to uie, dearest. 1 shall .;;et your hotter on Satnrday luorniiig, or perhaps before. Love to father, Margery, aud Jenny, and a llnaisand loves to yourself, dea.rest, J^'roui yf)ur aiieetionate husband, _ M. Fai; \h.\\. 5, Claremout (iardeus, (JIa.sgow : Monday, August 14, I8(i;i. I )l:AUl•:.■^T, Ilei'e is the fortidght complete siiu'o 1 left you and the thoughts ol my return to oxr lionic crowd in strongly ujiou my mind. N(.it tliat Ave are in any way uneared for, or left by our dear friends, save as i may desire for our own retire- uieut. Everybody has overfloAved Avith kindness, but you know their ]uanner, aud their desire, by your ftwu experience with uic. TJIE WJFE ANJ> 'J'HE (,)UEEX. 2o / I long to see you, dearest, and to talk over things t<:>getlier, and call to mind all the kindness I have received. My head is full, and my heart also, bat my recollection rapidly fails, even as regards the fiietids that are in the room with uie. You will have to resume your old function of being a iiillo\\' tmuymind, and a rest, a hapjiy-raaking wife. ^ly love to my dear Mary. I expect to ^nd you together, but do not assume to know how things may be. Jeannie's love with mine, and also Charlottu's, and a great many others which I cannot call to miiLd. Duarest, T long to see and be with you, A\hether together ur sejiarate. Your husband, vury affectionate, M. Faraday In ISo^S the Queen, at tlie suggestion of Prince Albert, "who nuich esteemed and vahied Faraday's genius, placed at his disposal for life a comfortable house on the green near Hampton Court. Faraday's only hesitation m accepting the offer was a doubt Avhether he could afford the needful repairs. On a hint of this reaching the Queen, she at once directed that it should be put into thorough repair inside and out. He still kept his rooms at the Royal Institution, and continued to live there occasionally. With the increasing infirmities of age, his anxieties for his wife seemed to be the only trouble that marred the serenity of his thought. Lady Pollock's narrative gives the following particulars : — Sometimes he was depressed by the idea of his wife left without kin — of the partner of his hopes and cares deprived of him. She had been the tirst love of his ardent soul ; she was the last ; she had been the brightest dream of his youth, and she was the dearest comfort of his age ; he never ceased for an 11 258 iMECHAEL FAHADAV. instant to feel liimself happy with her ; and he never for one Ijour ceased to care for her happiness. It was no wonder, then, that he felt anxiety about her. But he would rally from such a trouble with his great religious trust, and looking at her Avith moist eyes, he would say, " I must not be afraid ; you will be cared for, my wife ; you will be cared for." Fig. 22. — fauaday's h DME AT HAMPTON COURT. There are some who remember how tenderly he used to lead her to her seat at the Eoyal Institution when she was suffering from lameness ; how carefully he used to support her; how watchfully he used to attend all her steps. It did the heart good to see his devotion, and to think what the man was and Avhat he had been. Gradiuilly his powers \vaned. He gave his last juvenile lectures at Christmas, 1860 ; and in October, 1861, being now seventy years of age, he resigned his CLOSE OF SCIEXTIFIC OAriEER. 250 Professorship, while retaining the superintendence of the laboratory. "Xothino','' he wri.'te to the managers, '• wijuld make me happier in the things of this life than to make some scientihc discoverv or d'.-^'ii^lop- ment, and hx that to justifv the Board in their desire to retain me in riiy position here." His last research in the hiborator}" was made on March 12, l>Sij2. On June 20th he gave his last Friday night discourse — on Siemens's gas furnaces. He had, as his notes show, already made up his mind to announce his retirement, and the lecture was a sad and touching occasion, for the failure of his powers was painfully evident. He continued for tAvo years longer, and with surprising activity, to work for Trinity House on the subject of lighthouse illumination by the electric light. In 18G5 he resigned these duties to Dr. TyndaU. In 1864 he resigned his eldership in the Sandemanian church. In March, 1865, he resigned the position of super- intendent of the house and laboratories of the Ro3'al Institution. He continued to attend the Trida}* evenin^c nieetinf^s : but his tottering'' condition of frame and mind Avas apparent to all. All through the wdnter of 1865 and 1866 he became very feeble. Yet he took an interest in Mr. Wilde's descrip)tion of his new magneto-electric machine. Almost the last pleasure he showed on any scientific matter was when viewing the long spark of a Holtz's influence machine. He still enjoyed looking at sunsets and storms. All through the summer and autumn of 1866 and the spring of 1867 his physical powers waned. He was faith- fully and lovingly tended by his wife and his devoted niece, Jane Barnard. He was scarcely able to move, 260 MICHAEL FAKAOAY. but his mind " overtlowed " with the consciousness of the affectionate regard of those around him. He gradually sank into torpor, saying nothing and taking little notice of anything. Sitting in his cdiair in liis study, he died peacefully and painlessly on the 2Gth of Anoust, INllT. On the 30th of August he was quietl}' buried in Highgate Cemeter3\ his remains being connuitted to the earth, in accord- ance with the custom of the religious bod}^ to wdiicli he belonged, in perfect silence. None but personal friends Avere present, the funeral being by his own verbal and written wishes strictl}' simple and private. A simple unadorned tombstone marks the last resting- place of Michael Faraday. CHAPTER YIL VIEWS UN THE PURSUIT OF SCIENCE AND ON EDUCATION. Betaveen Faraday and the scientific men of his time there subsisted many various relations. The in- fluence which he exerted as a lecturer and as an experimental investigator was unique ; but, apart from such influences, those relations were mainly confined to individual friendships. With the organ- isation of science he had relatively very little to do. AVe have seen how highly he prized the honour of adniission to the Fellowship of the Royal Society ; and it remains to be told of the gratification with which he accepted the scientific honours which he received from almost every academy and university in Europe. Yet he took little part in the work of scientific societies as such. Four years after his election as F.R.S. he served on the Council, and he remained on*till 1X31. He served asirain in 1833 and LS35. He was not, however, satisfied with the management of the Royal Society, nor with the way in which its Fellowship was at that time bestowed on men who had no real claims on science, but were nominated through influence. Echoes of this 262 MiniAKI. FAItADAY. discontent arc to be found in varictus pnniphlots of the day by ]\[oll. l^abbagw South, and othors. i-'avaday, "wlio oditctl Clod's pamphlet, on the " decline ot' Science,'" is beheved to have had an even larLjei* share in its production. In 18;U) the ready scientific men amono-st the Fellows desired to place Sir John llerschel as President ; the less scientific preferred the l)nke ot" Sussex. Faraday took the unusual step ot" sj^eakini;" on the (luestion, advocatiuL;' tlie principle that emineni'c in science should be the sole ipiali- lication tor the l^residericy. Al the same meeting' Herschel moved, and b'aradaA' seconded, a, plan for retbrnun!.;' the Council h\ nominatin;^" a list, nl' tifty Fellows trt)m whose number the C'ouncil should be chosen. The\' carried their plan. ;uul Faraday's name Avas amongst those so selected to serve. F)Ut the ]>resitlential election went in favour of t.he Didvo of Sussex by 111) to 110 votes. After 1S;^5 Faraday never served ag'ain on the t'onncil. In lS4;i he wrote to Matteucci : — I think you are awaii' that I lia^c not alli'iuled at thr lioyal Society, either meetings or eouneil, for some years. Ill heaUh is one reason, and another that I do not like tlie l>iesent eoii.stitntioa of it, and want to restrict it to scientific men. As these my (iiiinions are not a.cce]ttal)K', I Imve >\itlub'awn from any management in it (still sending scientific eominunieations if 1 discover anything I lliink worthy). This, of course, deprives me of power theru Two months eai'licu' he wrote to th'ove, wht) at that time was carryino- out the lon^-needed reforms, sympathising, but detdining t.o co-operat,o : — i;el-^()1!M in the j;oval society. '2fJ-'j Royal Institution, December 21, 1842. My dear (tRove,^ . . . As to the lioyal Society, you know my feeling- towards it is for what it has been, and I hope ma}^ be. Its present state is not Avholcsome. You are aware that I am not on the council, and have not been for years, and have been to no meeting there for years ; but I do hope for better times. I do not wonder at your feeling-— all I meant to express was a wish that its circumstances and character should ini})rove, and that it should again become a desirable reunion of all really scientific men. It has done much, is now doing much, in some parts of science, as its magnetic observations show, and I hope will some day become alto- gether healthy. Ever, my dear Grove, yours sincerely, M. Faraday. Thougii he continued down to 18G0 to send researches for publication to the Eo3'al Societ}^, he seldom attended its meetings.* He was not even present m November, 1845, on the occasion of the reading of his paper on the action of the magnet on hght. In 1857 he declined the Presidency, though urged by the unanimous wish of the Council, as narrated on p. 225. Though in the meridian of his active life, he took '"' Once again did Faraday intervene in Koyul iSociety affairs at the crucial time when Lord Rosse was; elected President in 1S4S. The following excerpts from the journals of Walter White show the cause :— " Xovemher 25th. — There have heen many secret conferences this week— much trimming and time-serving. Alas fur human nature I " " November 30th. — The eventful da)-, the hallot hegim. Mr. Faraday made some remarks ahout the list," 264 MimiAKI. FAUAUAY. no part in the toundin^u;- of tlio Ikitisli Association in 1831, but Avas at tlio Oxford meeting in 1832, being one of the four sciontitic men (p. 05) selected to receive the honorary degree of ].).(! \j. on that occasion. Ho also conununicated a paper on Elcctro- clieniical 1 )ecoiupositiou to the IJ.A. meeting at (Jambridgc in 1S33. He acted as president of tlie Chemical Section of the Asso(nation in 1.S37 at Liverpool, and in 1 'S4(i at S(jutham])ton ; and Ik^ was chosen as vi(X!-[)resident of the Associjition itself in the years LS44, at York (p. 224); 1.S49, at Birmingham (p. 250); and 1.S53, at Hull, lie delivered evening discourses in 1.S47, a.t Oxford, on Mametic and I)iamai?'netic IMienomcna : and in 1(S49, at ]]irminghaiu, on Mr. (iassiot's llattery. He also contributed t(.) the ]>rocce(hngs at the meetings at Ipswich in 1S51 and at Liverpool in 1.S54. His comparative aloofness from scientific organi- sations arose probably from the exceedingly individuid nature of his own researches— to which allusion was made on p. 242 — rather than from any lack of sympathy. Ho had no jcaloiisy of co-operation in science. To Tyndall, then at Marburg, he wrote in 1850 rejoicing at the circumstance that tlie work on the niagnetic properties of crystals was being taken up by others. '' It is Avonderful," he says, '■ how nuich good results from different pei'sons working at the same matter. Each one gives views and ideas new to the rest. When science is a republic, then it gains ; and though I am no re- publican in other luattcrs, I am in that." Other causes there Avere, doubtless, tending to liis isolation. PraORITY IN SCIENTIFIC DJSOOVEUY. 265 amongst them an old jealousy, noAv long dead, against the RQjal Institution on the part of some of the Fellows of the Ro3'al Society. Above all, probably, Avas his detestation of controversy. Priority in scientific discovery was a matter which deeply concerned one whose life was devoted to scientific pioneering. To any question as to scien- tific priority between himself and other workers he was keenly sensitive. This was, indeed, natural in one who had voluntarily relinquished fortune, and retired from lucrative professional work, in the sole and single aim of advancing natural knowledge. His single-minded and sensitive nature made him particularly scrupulous in all such matters, and his early experiences must have added to the almost excessive keenness of his perceptions. Having had in 1823, when still merel}' assistant to Davy, to bear the double burden of a serious misunderstanding Mvith Dr. AVollaston as to the originality of his dis- covery of the electro-magnetic rotations, and of a serious estrangenrent from his master arising out of the liquid chlorine discovery — an estrangement which threatened to cause his election to the lioyal Society to be indefiniteh' postponed— he was in later life especially precise in dating and publishing his own researches. In 18*31 there arose, concerning his great discover}^ of magneto -electric induction, a curious misunderstanding. His discovery was, as we have seen, made in September and October. He collected his results and arranged them in the splendid me- moir — the first in the series cf '' Experimental Researches in Electricity " — which was read at the -66 MICHAEL FARADAY. Royal Society on Xovember 24-th. The resnrae of his work, -which he wrote five days later to Phillips, is given on pages 114-117. A fortnight later he wrote a shorter and hasty letter in the same way to his friend, M. Hachette of Paris — a letter which Faraday subsequently well termed " unfortunate," in view of the consequences that followed. M. Hachette, a week later, communicated Farada3''s letter to the Acadeuiie des Sciences on December 26th. It was published in Le Terivps of December 2Sth. At that date the complete memoir read to the Ptoyal Society was not yet printed or circulated. The consequence was that two Italian ph3^sicists, MM. Nobili and Antinori, seeing the brief letter, and '" considering that the subject was given to the philosophical world for general pursuit," immediately began researches on magneto-electric induction in ignorance of Faraday's full work. Their results they embodied in a paper. in which they claimed to have "verified, extended.- and, perhaps, rectitied the results of the English philosopher," accusing him of errors both in ex- periment and theor}^, and even of a breach of good faith as to what he had said about Arago's rotations. This paper they dated January 31st, 1832 ; but it was published in the belated number of the Avtologia for November, 1831, where its appearance at an apparently earlier date than Faraday's original paper in the Fhiloscqjhical Transactions made many Continental readers suppose that the researches of Xobili and Antinori preceded those of Faraday. In June, 1832, Faraday published in the Fhilosopltical Magazine a translation of Nobili's memoir, Avith his PltHyRlTY IX PUBLICATION. 267 own annotations; and later in the year he wrote to Ga}^ Lnssac a long- letter on the errors of Nobili and Antinori. He showed how, in spite of his efforts to clear up the misunderstanding, in spite of his having sent several months previously to MM. Nobili and Antinori copies of his original papers, no cor- rection or retractation had been made by them ; and he concluded b}^ a dignified protest that none might say he had been too hasty to write that which might have been avoided. It may be taken that the rule now recognised as to priority of scientific publication — namely, that it dates from the day when the dis- coverer communicates it formally to any of the recognised learned societies — was virtually established by Faraday's example. It will be remembered that writing to De la Rivo in 1845, to tell him of his diamagnctic discoveries, he begged him to keep the matter secret, adding; " I ought (in order to ])reserve the respect due to the Royal Society) not to write a description to any one until the paper has been re- ceived or even read there." To younger men he incul- cated the necessity of proper and prompt publication of their researches if they would reap the benefit of their work. To Sir William Crookes, then a rising young chemist, he said : " Work, Finish, Publish." AVriting in 1858 to Professor Mattcucci, who had been annoyed with him for allowing Du Bois Reymond, with whom Matteucci had had some controversy about priority, to dedicate his book to him, Faraday says : " Who has not to put up in his day with insinuations and misrepresentations in the accounts of his proceedings given by others, bearing for the 2GN ]MI(.'IIAKI- KAKADAV. time tlio present injustice, which is often uninten- tional, and often orio'inates in lia.sty temiu^r, a.nd conimittiuL;- his fame and eliaraet.er to the judgment of the men of his own and future time T' . . . "I see that tliat moves. 3'ou whicli would move mo most — namely, l-he imjMitation of a want <)f i^-ood faith— and I conliidly sym]tathisc with any one who is so ehar^'cd unjustly. Such cases have seeuKMl to mc almost the only ones for wliich it is worth while enterinu^ into c.ontrt)versy. " . . . "These ])olemi('s of the scientific world ;ire very unfortuna,tc (,hin<^\s; tliey form the i^a'cat stain to which tlie hca.utiliil editic(^ of scientitic truth is suhjeet. A ir. Iliof ■I umidhlc V Controversy whether in reli^^'ion oi* sf^it^ice was to him alil\(^ dete-stahU^ lie look no pai't in |)ohl,ics. A letter to Tyndall (see" Faraday as a Discoverer," p. :i!'), wi'itten after the latter had told him of a rather hnitcd (hseussion at the Jiritish Asso(;iation nu^etinL,'' in lsr>5, speaks of his own efforts at forhearanee. Jh?. says: — 'I'licsc , Invent mocliii,L,^s, f)f wliicli I lliink viny well aItn;^i'.Un',r, ;"i(l\';ilir(' science, cliieliy 1 ly ln'iii,i;iM,i;' scieiitillc men togctlief iiiii! niakiiiK tlieiu to know and lie frienits with each olkev ; and i am sorry when that is not the effect in every jitu't of thi-ir course. . . . The |-eul Irnth never fails ultimately to il]i]iear. . . It is better to he hiind to llii; resnils of ]iartisanshi]t, and (|uii'k to see ;;iM>d will. < )ne has more lia]i|iiness in mieself in endeavtairini; to follow the thin,L,^s Ijia.t make for |ieiice. \ nii can hardly inia,gine Jiow uftc^n I have lieea heated in jirivate when ojijiosed, as I have tlion^lit nn- jastly and superciliously, and yet \ ha\e slriven, and snccei^led I hnpe, in keepiii.L,^ down replies of I he like kiiiil. And I know I have never lost hy it. HATRED OF 0()NTH(.)\'EKSY. 269 J)ui'ing the yeiws when ho was examining the apparatus of rival inventors for Hghthouse illumina- tion, ho Could cahnly hoar them (.lescrihcd as Mr. So- and-So's electric lii^hts, all the while knowino- that it was his own discovery of magneto-electric induction which had made the mechanical production of electric light possible. Yet he hred up if anyone dared to revive the priority dispute between Davy and Stephen- son as to the invention of the safety lamp. " Dis- graceful subject," was his own connnent. In his dispute with Snow Harris as to the design of lightning- rods, in which, as it is now known, Snow Harris was right : in his dispute with Airy over the curved lines of force ; in his minor difhculties over Hare's pile and Becquerel's magnetic observations, none could either assert his own position with more simple dignity, nor admit with o'reater frankness the riy-hts of his rival. To Hare he Avrote : — You must excuse uie, however, for several reasons from answering it [Hare s letter] at any length ; the tirst is my distaste for controversy, which is so great that I would on no account our correspondence should acquire that character. I have often seen it do great harm, and yet remember few cases in natural knowledge where it has helped much either to pull down error or advance truth. Criticism, on the other hand, is of nmch value. When we reflect how^ large a part of his experi- mental researches was devoted to establishing the relations betAveen the various forces of nature, we cannot but think that Faraday must have regarded with somewhat mixed feelings the publication in 1846 of Sir AYilliam Grove's volume on the Correlation of 270 MICHAEL FARADAV. Forces. He bud, in June, 1834, given a course of lectures on the mutual relation of clieuiioal and electrical phenomena, and had dealt therein with the conversion of chemical and electrical power into heat, and had speculated on the inclusion of gravitation in these mutual relations. In 1858 Faraday marked the old lecture notes of these lectures "with his initials, and endorsed theui with the words '' Correlation of Physical Forces." Probably none rejoiced more than he that Grove had undertaken the work of popularising the notion which for a score of years had been familiar to himself. Yet he was keen to resent an unjust reflection, as is shown by his letter to Richard Phillips, republished in Vol. II. of the " Experimental Re- searches," p. 229, respecting Dr. John Davy's Life of Sir Humphry. Farada)^ has himself left on record (p. 10) that when he wrote to Davy asking to be taken into his employ- ment, his motive was his desire " to escape fronr trade, which I thought vicious and selfish, and to enter into the service of Science, which, I imagined, made its pursuers amiable and liberal." Davy had smiled at this boyish notion, and had told him that the experi- ence of a few 3'ears would correct his ideas. Years afterwards he spoke of this matter to Mrs. Andrew Crosse in an interview Avhich she has recorded : — After viewing the ample appliances for experimental research, and feeling much impressed by the scientific atmo- sphere of the place, 1 turned and said, "Mr. Faraday, you must be very happ}^ in your position and with your pursaits- which elevate you entirely out of the meaner aspects and lower aims of common life." HOXOUUS AKD TITLES. 271 He filiook his head, and with that wonderful mobility of countenance which was characteristic, his expression of joyousness chati,i:,'ed to one of profound sadness, and he replied : "When I quitted business and took to science as a career, I thought I had left behind nie all the petty meannesses and stuall jealousies which hinder man in his moral progress ; but I found myself raised into another sphere, only to find poor human nature just the same everywhere — subject to the same weaknesses and the same self-yeeking, however exalted the intellect." These were his words as well as I can recollect ; and, looking at that good and great man, I thought I had never seen a countenance which so impressed me with the character- istic of perfect unworldliness. Probably few men have ever been recipients of so many scientific honours as Faraday. Beginning in the year 1828 witli his election as a corresponding member of the Academic des Sciences of Paris, and as an honorary member of the Cambridge Philosophical Society, the hst of his diplomas and distinctions — some ninety-seven in number — ended in 1SG4 with his election as Associate of the Ptoyal Academy of Sciences of Naples. It included honours from almost every academy and university of Europe. These honours Faraday valued very highly ; and whilst he consigned his various gold medals to a mere wooden box, his diplomas were kept with the utmost care in a special diploma book, in which they were mounted and indexed. To Mr. Spring Rice, who in 1838 asked him for a list of his titles, he replied, enclosing the hst, and adding this remark : " One title, namely that of F.R.S., was sought and paid for ; all the rest are spontaneous offerings of kindness and goodwill from 272 MICHAEL FARADAY. the bodies naiuecl." Years afterwards ho was asked by Lord Wrottesley to advise the Govei-ninent as to how the position of science or of the cultivators of science in England might bo improved. The letter is so characteristic that it cannot be spared : — Royal [ij^titutioii : March 10, 1854. My Lord, — I feel unfit to give a deliberate opinion on the course it might Ije advisable for the Government to pursue if it were anxious to improve the position of science and its cultivators in our country. ^ly course of life, and the circum- stances which make it a liappy one for me, are not those of ]»ersoiis Avho conform to tlie usages and habits of society. Througli the kindness of all, from my Sovereign dowuAvards. I have that which supplies all my need ; and in respect of honours, I have, as a scientific man, received from foreign countries and sovereigns those wdiich, belonging to very limited and select classes, surpass in my opinion anything that it is in the })0\ver of my own to bestow\ I cannot say that I have not valued such distinctions ; on the contrary, I esteem them very highly, but I do not think I have ever worked for or sought after them. Even w^ere such to be now created here, the time is past wdien these would possess any attraction for nie. . . AVithout thinking of the eU'ect it might have upon distin- guished men of science, or upon the minds of those who, stimulated to exertion, might become distinguished, I do think that a government should, /or its oivn sake, honour the men who do honour and service to the country. I refer now to honours only, not to beneficial rewards. Of such honours, I think, there are none. Knighthoods and baronetcies are sometimes conferred with such intentions, but I think them utterly unfit for that purpose. Instead of conferring distinc- tion, they confound the man who is one of twenty, or perha].is fifty, with hundreds of others. They depress rather than exalt him, for they tend to lower the especial distinction of mind to the commonplace of society. An intelligent country HOW SCIENCE CAX BE HONOURED. 273 ou^llt to recognise tlic scientific men amongst its people as a class. If honours are conferred n[)on eminence in any class, as that of the law or the army, they should be in this also. The aristocracy of the class should have other distinctions than those of lowly and high-born, rich and poor, yet they should be such as to be worthy of those whom the sovereign and the country should delight to honour ; and, being rendered very desirable, and even enviable, in the eyes of the aristocracy by birth, should be unattainable except to that of science. Thus much, I think, the Government and the country ought to do, for their own sake and the good of science, more than for the sake of the men Avho might be thought worthy of such distinction. The latter have attained to their fit place, whether the community at large recognise it or not. . . . I have the honour to be, my lord, your very faithful servant, M. Faraday. To Professor Andrews lie wrote in 184o in a similar strain : — I have always felt that there is something degrading in ottering rewards for intellectual exertion, and that societies or academies, or even kings and emperors, should mingle in the matter does not remove the degradation, for the feeling which is hurt is a point above their condition, and belongs to the respect which a man owes to himself. . . . Still, I think rewards and honours good if properly distril)uted ; but they should be given for what a man has done, and not offered for what he is to do. When a friend wrote to him on hearing a rumour that he had hirnseh' been knighted, his reply, published years after in the London Revieiv, was : " I am happ3^ that I am not a Sir, and do not intend (if ii. depends upon me) to become one. By the Prussian s 274 MICHAEL FAEADAY. knighthood* I do feel honoured: in the other I should not." On one occasion he commented rather sarcasti- cally upon the British Government and its stinginess as compared with those of all other civilised countries in its aids to scientific progress. This complaint is equally justified to-day. To niany it may be news that England pays to its Astronomer Royal — who must obviously be a person of very high scientific qualifications — a salary less than those paid to the five assistant under-secretaries in the Colonial and Foreign Offices ; less than that paid to the sergeants- at-arms in the Houses of Parliament : less than that paid to the person appointed Director of Clothing in the War Office. Enlicchtened Encrland ! Faraday did not deem the pursuit of science to be necessarily incompatible with what he termed " pro- fessional business" — that is, expert work. Until the day when he abandoned all professional engagements, so as to devote himself to researches, he had been receiving a considerable and growing income from this source. But he objected to the indignities to which this work exposed him from lawyers, who would not understand that he took no partisan view. He could not endure the browbeating of cross- examining counsel. The late Lord Card well was witness to a gentle but crushing reproof Avhich he once administered to a barrister Avho attempted to bully him. A writer in the British Qao/rtcrbj Review " He was a Cheviiliur of the Prussian Order of Merit, also Com- mander in the Legion oE Honour, and Knight Commander of the Order of St. Maurice and St. Lazanis. UXrVERSlTY DEGREES IN SCIENCE. 275 attributes to a specific case his determination to cease expert work. He gave evidence once in a judicial case, when the scientific te.stijuouy, starting from given premises, was so diverse that the presiding judge, in summing up launched something like a reproach at the scientific witnesses. " Science has not shone this day," was his lordship's remark. From that time forth no one ever saw Faraday as a scientific witness before a law tribunal. Amongst the honours received by Farada}^ there was one of which, in 1S3S, he said that he felt it equal to any other he had received — namely, that of Member of the Senate of the University of London, to which position he was nominated in 1S36 by the Crown. For twenty-seven 3^ears he remained a senator, and when, in 1859, the project for creating degrees in science was on foot, he was one of the committee who drew up a report and scheme of examiiiation for the Senate. To the Rev. John Barlow he wrote on this matter: — The Senate of the University accepted and approved of the report of the Conunittee for Scientific Degrees, so that that will go forward (if the Government approve), and will come into work next year. It seems to give much satisfaction to all who have seen it, though the subject is beset with difficulties; for when the depth and breadth of science came to be considered, and an estimate was made of how much a man ought to know to obtain a right to a degree in it, the amount in words seemed to be so enormous as to make me hesitate in demanding it from the student ; and though in the D.S. one coukl divide the matter and claim eminence in one branch of science, rather than good general knowledge in all, still in the B.S., which i.s a progressive degree, a more extended though a more superficial acquaintance seemed to be reiiuired. In fact, the matter is so new, and there is so little that can 270 MH'UAEL FAUAJJAV. serve as a previous expei'ieuce in the iounding and arraii;,dii;;j these degrees, that one must leave the whole eiideavoiir to shape itself as the practice and experience accumulates. When, in 1863, his feebleness impelled him to resign this position, he wrote to Dr. Carpenter : — Tlje ]iosition of a senator is one that should not be held by an inactive man to the exclusion of an active one. It has rejoiced my heart to see the jtrogress of tlte University, and of education under its inliuence and power ; and that delight I hope to have so long as life shall be spared to me. He had little sjnnpathy with either text - book science or with mere examinations. " I have far more confidence," he wrote, " in the one man who works mentally and bodily at a matter than in the six who njerely talk about it. Nothing is so good as an experiment which, whilst it sets error right, U'ives an aljsolute advancement in knowled'i^e." In another place he wrote : — " Let the imagination go, guarding it by judgment and principles, but holding it in and directing it by expjerinient." For book- learned chemistry and mere chemical theory, apart from expjerirnental facts, he had an undisguised con- tempt, Writing to General Portlock on the subject of chemical education, he stated that he had been one of the Senate of the University of London appointed to consider especially the best miethod of examination. They had decided on examination by papers, accompanied by vivd voce. " We think," he added, '■ that no numerijcal value can be attached to the rjuestions, because eveiything depends on hoi'j they are o/iisv:ered!' Then, referring to the teaching at AVoolwich, he says, "My instructions always have SCIENCE AND THE UNIVERSITIES. 277 been to look to the note-books for the result." "Lectures alone cannot be expected to give more than a general idea of this most extensive branch of science, and it would be too much to expect that young men who at the utmost hear only fifty lectures on chemistry should be able to answer with much effect, in Avriting, to questions set down on paper, when we know by experience that daily work for eight hours in practical laboratories for tJiree ■months does not go very far to confer such ability." He had, at an earlier date, declined to be ap- pointed as examiner in the University. He had previously declined the professorship of che]nistry in University College ; and he had also declined the chemical chair in the University of Edinburgh. This was not, however, from any want of sympathy with university work, or faikire to appreciate the ideal of a university as a seat of learning. Writing to Tyndali, in 1851, about another university — that at Toronto — he said : " I trust it is a place where a man of science and a true philosopher is required, and where, in return, such a man would be nourished and cherished in proportion to his desire to advance natural knoAvledge." At the same time he had an exceeding repugnance to the custom of expecting candidates for professorial chairs to produce " testimonials " of their qualifica- tions. When his intimate friend Richard Phillips was a candidate for the very chair which Faraday refused at University College, Faraday declined on principle to give a testimonial " I should indeed have thought," he added, " his character had been :^7.S MICHAEL FAKADAV. known to be such that it would rather have been degraded than estabKshed b}^ certificates." Similarly, in 1851, he told Tyndall, then an applicant for the Chair of Physics at Toronto, that he had in every case refused for many years past to give any on the application of candidates. " Nevertheless, he added, " I wish to say that when I am asked about a candidate by those Avho have the choice or appoint- ment, I never refuse to answer." On general education, Faraday's ideas were much in advance of his time. From the epoch when as a young man he lectured to the City Philosophical Society on the means of obtaining knowledge and on mental inertia, down to the cluse of his career, he consistently advocated the cultivation of the experi- mental method and the use of science as a means of traininsi' the faculties. A concise account of his views is to be found in the lecture he gave in 1854 before the Prince Consort on " Mental Education," a lecture which prescribes the self-educating discipline of scientific study and experiment as a means of correct- ing deficiency of judgment. It included a powerful plea for suspense of judgment and for the cultivation of the faculty of proportionate judgment. In 1SG2 he w^as examined at some length by the Ptoyal Com- missioners upon Public Schools. With them he pleaded strongly for the introduction of science into the school curricula : and wdien asked at what age it mio-ht be serviceable to introduce science-teachinof, rephed : " I think one can hardly tell that until after experience for some few years. All 1 can say is this that at my juvenile lectures at Christmas time I have SCIENCE IN EDUCATION. 279 never found a child too young to understand intelli- gently Avbat I told him ; they came to me afterwards with questions which proved their capability." One passage from the close of a lecture given in 185S deserves to be recorded for its fine appreciation of " the kind of education which science offers to man " : — It teaches us to be neglectful of nothing, not to despise the A/iKfJl l>eginni]igs— they yu'ecede of necessity all great fhiuf/!^. . . . It teaches a continual comparison of the i^ntaU (Did f/reat, and that under differences alnntst approaching the iiiHnite, for the small as often contains the great in princijile as the great does the small ; and thus the mind becomes comprehensive. It teaches to deduce iirinciples carefully, to hold them firmly, or to suspend the judgment, to discover and obey !(.(/'', and by it to be bokl in applying to the greatest what we know of the smallest. It teaches us, first l)y tutors and books, to learn that Avhicli is already known to others, and then by the light and methods which belong to science to learn for ourselves and for others ; so making a fruitful return to man in the future for that which we have obtained from tlie men of the past. Bacon in his instruction tells us that the scientific student ought nnt to be as the ant, who gathers merely, nor as the spider who spins from her own liowels, l)ut rather as the bee who both gathers and produces. All this is true of the teaching afforded by any part of physical science. Electricity is often called wonderful, beautiful ; l>ut it is so only in common with the other forces of nature. The beauty of electricity or of any other foi-ce is not that the power is mysterious, and unexpected, touching every sense at unawares in turn, but that it is under iam^ and that the taught intellect can even now govern it largely. The human mind is placed above, and not beneath it, and it is in such a point of view that the mental education aH'orded by science is rendered super-eminent in dignity, in practical api>lication and utility ; for l>y enabling the mind to apply the natural power thruugh law, it conveys the gifts of Glod to man. 2S0 MICHAEL FARADAY. A peculiar interest attaches to Faraday's attitude towards tlie study of mat hematics. He who had never had any schoohng beyond the common school of his parish had not advanced beyond the simplest algebra in his master}' over symbolic reasoning. Several times in his ''Experimental Eesearches " he deplores what he termed '' my imperfect mathe- matical knowledc^e." Of Poisson's theory of rnao-netism he said: ''I am quite untit to form a judgment." f)r. Scoftern repeats a pleasantr}' of Faraday's having on a certain occasion boasted that he had once in the course of his life pertormed a mathematical operation — when he turned the handle ot Babbage's calculating machine. Certain it is that he went through the whole of his rnagniticent researches without once usino- even a sine or a cosine, or anythinu' more recondite than the simple rule-of-three. He ex- pressed the same kind of regret at his unfamiliarit}' with the German lanL;uai=^e — " the lan^aiaoe of science and knowledge," as he termed it in writing to Du Bois Rej-niond — which prevented him from reading the Ayorks of Professor *'Ohnjs." Xevertheless he valued the mathematical powers of others, and counselled Tyndall to work out his experimental results, " so that the mathematicians niay be able to take it up." Yet he never relaxed his preference for proceeding along the lines of experimental investigation. His curious phrase (p. 239) as to his picpie respecting mathematics is very signiticant, as is also his note of jubilation in his letter to Phillips (p. 117) at tinding that pure experiment can successfull}' rival mathematics in unravellino" the mysteries which had eluded the efforts ON MATHEMATICS. 281 of Poisson and Araoo. Ho himself attributed to his defective memory his want of hold upon symbolic reasonmg. To Tyndall he wrote in 1851, when thank- ing him for a copy of one of his scientific memoirs :- — Such piipers aw your.s make me feel more than ever the loss :)f memory I have sustained, for tliere is no reading them, or at least retaining the argument, under such deficiency. ^Mathematical formuke more than anything require quick- ness and surety in receiving and retaining the true value of the symbols used ; and when one has to look back at every moment to the beginning of a pajjcr, to see what H or A or B mean, tliere is no making way. Still, though 1 cannot hokl the whole train of reasoning in my mind at once, I am able fully to a]ipreciate the value of the results you arrive at, and it appears to me that they are exceedingly well established and of very great conse(|uence. These elementary laws of action are of so much consequence in the development of the nature of a power which, like magnetism, is as yet new to us. Aa^ain to Clerk Maxwell, in 1857, he wrote: — There is one thing I Avould l.ie glad to ask you. When a mathematician engaged in investigating physical actions and results has arrived at his own conclusions, may they not be exjiressed in common language as fully, clearly, and definitely as in mathematical formuke^ If so, would it not be a great boon to such as we to express them so — translating them out of their hieroglyphics that w^e also might work upon them by experiment 'I I think it must I)e so, because I have always found that you could convey to me a jjerfectly clear idea of your conclusions, which, though they may give me no full understanding of the steps of youi- pi"ocess, gave me the results neither above nor below the truth, and so clear in character that I can think and work from them. If this be possible, would it not be a good thing if mathe- maticians, writing on these sultjects, were to give us their 2.S2 MICHAEL FARADAY. results in this po])u]ar useful Avorkin.ij,- state as well as in that ^\■hich is tlieir own and proper to them 'I The achievement of Faraday in finding for the expression of electromagnetic laws means which, though not symbohc, were simple, accurate, and in advance of the mathematics of his time, has been alhided to on page 217. Liebig, in his discourse on " Induction and Deduction," refers to Faraday thus : — I have heard mathematical ])hysicists dei)lore that Faraday's records of his labours were ditticult to read and understand, that they often resembled rather abstracts from a diary. But the fault was theirs, not Faraday's. To physicists who Lave approached i>hysics by the road of chemistry, Faraday's memoirs sound like an admirably beautiful music. Von Helmholtz, in his Faraday lecture of 1881, has also touched on this aspect. Now that the niatheiiiatical interpretation of Faraday s conceptions regarding the nature of electric and magnetic forces has been given by Clerk Maxwell, we see how great a degree of exactness and precision was really hidden behind the words which to Faraday's contemporaries appeared either vague or obscure ; and it is in the highest degree astonishing to see what a large number of general theorems, the methodical deduction of which requires the highest powers of mathe- matical analysis, he found by a kind of intuition, with the security of instinct, without the help of a single mathematical formula. Two other passages from Von Hehnholtz are worthy of being added : — And now, with a quite wonderful sagacity and intellectual lirecision, Faraday performed in his brain the work of a great mathematician without using a single mathematical formula. MAXWELL AND VON HELMHOLTZ. 283 He saw with his mind's eye that magnetised and dielectric bodies ought to have a tendency to contract in the direction of the lines of force, and to dilate in all directions perpen- dicular to the former, and tliat by these systems of tensions and pressures in tlie si)ace which surrounds electrified bodies, magnets, or wires conducting electric currents, all the pheno- mena of electrostatic, magnetic, electromagnetic attraction, repulsion, and induction could be explained, without recurring at all to forces acting directly at a distance. This was the part of his path where so few could follow him ; perliaps a Clerk Maxwell, a second man of the same power and in- dependence of intellect, was needed to reconstruct in the normal methods of science the great building the plan of which Faraday had conceived in his mind, and attempted to make visible to his contemporaries. Nobody can deny that this neAv theory of electricity and magnetism, originated l.»y Faraday and developed by Maxwell, is in itself well consistent, in perfect and exact harmony with all the known facts of experience, and does not contradict any one of the general axioms of dynamics, which have been hitherto considered as the fundamental truths of all natural science, because they have been found valid, without any exception, in all known processes of nature. And, after dealing w^itli the phenomena discussed by Faraday, Von Helmholtz adds these pregnant words : — Nevertheless, the fundamental conceptions by which Faraday was led to these much-admired discoveries have not received an equal amount of consideration. They were very divergent from the trodden path of scientific theory, and appeared rather startling to his contemporaries. His principal aim was to express in his new conceptions only facts, with the least jtossible use of hypothetical substances and forces. This was really an advance in general scientific method, destined to i)urify science from the last remnants of meta- physics. Faraday was not the first, and not the only man, :^y the rest of the elders on two rows of seats elevated neross the end of the chapel, one row above the otlier. The ground lloor Avas filled with the old-fashioned hi^h pews, and tliere was a gallery above on both sides, also with pews. Fara- day sat in a ])ew on the ,i;Tiinml lloor, about the middle. There was a large table on the IhKtr nf llic chapel in front of the elders' seats. The presinutlis were then called, to distinguish them from the sliopkeei)ers who then, as now, called themselves "silversmiths," though fre- ipiently making none of the goods they sell. His manufactory was for a time at Amen Court, Paternoster Row ; afterwards it was removed to a large building ei'ccted by the firm at 7\ugel (Street, near the General Post Ofhce, and the business has since been carried on l»y the sons and grandsons. RELIGIOUS SERVICE. 295 Mr. Barnard and his family worshipped at the Sande- manian Chapel. To this chapel Faraday walked every Simdny morning from his earliest days ; he never kept a carriage, and on religious principles' Avould not hire a cab or omnibus on the Lord's day.^" The service commenced at eleven in the morning and lasted till about ouej after which the members — " brothers and sisters," as they called each other — liad their midday meal "in common" in the room attached to the chapel, which has already been referred to. The afternoon worship usually ended about five o'clock, after partaking of the Lord's Supper. The services were very much like those of the Congrega.tionalists, and consisted of extempore prayers, hynms, reading the Scripture, and a sermon, usually by the presiding elder. Faraday had been an elder for a great many years, and for a consideral.>le time was the presiding elder, and conseijuently preached ; but during this time reliiKjuished his office. There was one peculiarity in the service ; the Scriptures were not read by the presiding elder, but he called on one of the members to read ; a.nd when Faraday was there — which he always was when in London— the pre- siding elder named " Brother Michael Faraday," who then left his pew, passing along the aisle, out of the chapel, up the stairs at the back, and reappeared behind the presiding elder's seat, who had already opened the large BilJe in front of him, and ])ointed out the chapter to be read. It was one of the richest treats that it has been my good fortune to enjoy to hear Faraday read the Bible. The reader was quite unaware what he Avas to read until it was selected and when one chapter of the Old Testament was finished another would be given, probably from the New Testament. Usually three chapters were read, and sometimes four, in succession ; but if it had been half a dozen there would have been no weariness, for the perfection of the reading, with its clearness of pronunciation, its judicious emphasis, [* This is not altogether accurate. Certainly in his later Ufo Faraday used to hire a cab to take him and Mrs. Faraday to the chap(-.a." fS. P. T.] 296 MICHAEL FARADAY. the rich musical voice, and the perfect chanii of the reader, Avith his natural reverence, made it a delight to listen. I have heard most of those who are considered our best readers in church and chapel, but liave never heard a reader that I considered equal to Faraday. At this distance of time his tones are always in my ears. I was told by members of the chapel tliat he was most assiduous in visitin;^^ the poorer brethren and sisters at their own homes, comforting them in their sorrows and afflictions, and assisting them from his own purse. Indeed, they said, he was continually pressed to be the guest of the high and noble (which we may well believe), but he would, if possible, decline, preferring to visit some poor sister in trouble, assist her, take a cup of tea with her, read the Biljleand pray. Though so full of religion, he was never obtrusive with it ; it was too sacred a thing. Tyndall has preserved another vivid reminiscence of Faraday's inner life, wdiicli he wTote down after one of the earliest dinners which he had in the Royal Institution. " At two o'clock he came down for me. He, his niece, and myself formed the party. ' I never give dinners,' he said ; ' I don't knoAv how to give dinners ; and I never dine out. But I should not like my friends to attribute this to a wrong cause. I act thus for the sake of securing time for Avork, and not through religious motives as some imagine.' He said grace. I am almost ashamed to call his pra3^er a saying ' of grace. In the language of Scripture, it might be described as the petition of a son into whose heart God had sent the Spirit of His Son, and who with absolute trust asked a blessing from his Father. We dined on roast beef, Yorkshire pudding, C5 ELDEUSHU' INTERRUPTED. 297 and potatoes, drank sherry, talked of research and its requirements, and of his habit of keeping himself free from the distractions of society. He Avas bright and joyful — boylike, in fact, though he is now sixty-two. "His work excites admiration, but contact with hiui warnjs and elevates the heart. Here, surely, is a strong man. I love strcjigth, but let me not forget the example of its union with modesty, tenderness, and sweetness, in the character of Faraday." There is a story told by the Abbe Moigno that one day at Faraday s request he introduced him to Cardinal Wiseman. In the frank interview which followed, the Cardinal did not hesitate to ask Farada}^ whether, in Ins deepest conviction, he believed all the Church of Christ, holy, catholic, and apostolic, was shut up in the little sect in Avhich he was ofHcially an elder. "Oh, no!" was Faraday's reply; "but I do believe from the bottom of my soul that Chiist is with us." The course of Faraday's eldership was, however, interrupted, It was expected of an elder that he should attend ever}^ Sunday. One Sunday he was absent. When it was discovered that his absence was due to his having- been " commanded " to dine with o the C^'Jeen at Windsor, and that so far from expressing penitence, he was prepared to defend his action, his office became vacant. He was even cut off' from ordinary membership. Nevertheless, he continued for years to attend the meetings just as before. He would even return from the provincial meetings of the British Association to London for the Sunday, so as not to be absent. In 1800 he Avas received back as 29s MICHAEL FARADAY. iLii elder, which office lie held agam for about three years and a half, and finally resigned it in 1864. It is doubtful whether Faraday ever attempted to form any connected ideas as to the nature or iriothod of operation of the Divine government of the physical world, in which he had such a whole-souled belief. Newton has left us such an attempt. Kant in his own way has put forward another. So did Herschol ; and so in our time have the authors of "The Unseen Universe." To Faraday all such "natural theology" would have seemed vain and aindcss. It was no part of the lecturer on natural philosophy to speculate as to final causes behind the physical laws with which he dealt. Nor, on the other hand, was it the slightest use to the Christian to inquire in what way Clod ruled the universe : it Avas enough that He did rule it. Faraday's mental (jrganisation, which made it possible for him to erect an absolute barrier between his science and his religion, was an unusual one. The human njind is seldom built in such rigid compart- ments that a man whose whole life is spent in analysing, testing, and weighing truths in one dejjart- ment of knoAvledge, can cut himself off from applying the same testing and inquiring processes in another department. The founder of the sect hud taught them that the Bible alone, with nothing added to it or taken away from it by man, was the only and sufficient guide for the soul. Apparently Faraday never admitted the possibility of human flaw in the printing, editing, translation, collation, or construction of the Bible. He apparently never even desired to know how it compared with the oldest manuscripts, or what was RELIGIOX AND SCIENCE. 299 the evidence for the authenticity oF the vai-ions versions. Having once accepted the views of his sect as to the absohite inspiration of the EngUsh Bible as a whole, he permitted no subsequent question to be raised as to its literal authority. Tyndall once described this attitude of mind in his own trenchant way by saying that Avhen Faraday opened the door of his oratory he closed tliat of his laboratory. The saying may seem hard, but it is essentially true. To few indeed is such a limitation of character possible : possibly it may be unique. We may reverence the frank single-minded simplicity of soul which dwelt in Farada}^ and may yet hold that, whatever limitation was right for him, others would do wrong if they refused to bring the powers of the mind — God-given as they believe — to bear upon the discovery of truth in the region of Biblical research. Yet may none of them dream of surpassing in transparent honesty of soul, in genuine Christian humility, in the virtues of kindness, earnestness, and sympathetic devotion, the great and good man who denied himself that freedom. INDEX AlDbott, Benjamiii, 7, H, 97, 227; letters to, 7, 0, lo, 22, 20, 20, 41, 44, 228 Acoustical researches, loC) Action at a distance uuthinkal^le, 12,S, 153, 157, 216 Admiralty, Scientilic adyiser to the, C8 _iEther, the. Speculations ui:>on , 193, 213 Air}', Sir Geoi'ge, Dispnte with, 269 Aloofness from sciontihc organisa- tions, 261 Ampere, Andrtie Maiie, Meeting with, 19; his researches, 80, 82, 85, 105, 126 Analyst, Faraday' s professional work as, 51, 61, "63, 274 Anderson, Sergeant, engaged as assistant, 96 ; his imj^licit obedi- ence, 97, 242 Andrews, Professor T., Letter to, 273 Apparatus, Simplicity of, 239 Arago, F., Meeting with, 34, 238 ; his notations, 106, 116, 118; his philosophical reserve, 107 Armstrong, Lord, on electrification of steam, 170 Artists amongst acquaintances, 246 Astley's Theatre, 51 Athenfeum Club, 59 Atmospheric magnetism, 206, 209, 210 Atoms or centres of force, 241 Autobiographical notes, 8, 17, 50, 58, 70, 71, 73, 76, 223, 243 B. Babbagc, Charles, 107, 116, 202 Barnard, Edward, 4l) , Frank, 250, 286 , George, 46, 51, 71, 89, 224, 246, 294 — , Miss Jane, 46, 259 , Sarah (Mrs. Faraday), 46, 294 Becker, Dr., Letter to, 244 Beuce Jones's " Life and Letters of Faraday," 7, 26, 40, 43, 48, 57, 58, 78, 108, 199, 226, 231, 293 Benzol, Discovery of, 94, 101 Bidwell, S., magnetic action of light, 184 Biographies of Faraday (see Pee- FACt:) Boltzmann : on crystalline dielec- trics, . 166 ; on the doctrines of Faraday and Maxwell, 216 Bookbinding, 5, 6, 17, 249 Bookselling, 5, 17, 26, 31 Books by Faraday: — "On the Means of Obtaining Know- ledge," 41 ; "Chemical Manipu- lations," 101, 233; "On Alleged Decline of Science in England" (editor), 110; "Experimental Kesearches in Electricity and Magnetism," 102; "Experi- mental Researches in Cheniistry and Physics," 76; " Un the Prevention of Dry Hot in Tim- ber," 149 ; " Chemistry of a Candle," 234; "The Forces of Nature," 234 .302 MICHAEL FARADAY. Buots, a home-made pair of, 240 Braude, W. F., Prof., ;J9, ;')? Breakdown in health, 170, 1!I9, 222, 259 British Association, GI, 224, 204, 268, 207 Browiiinn;, Mrs. E. B,, denounces Faraday, 2ol Burdett-Coutts, Baronnss, Letter to, 240 C. Cards, L'^se of, to assist memory, 7, 239 Charge, eloetric, (^uei-y as to seat of, 1.'.4 , The nature of an electric, 152 Charitable gifts, 215, 29fl Chemical researches, 45, 82, S7 ; analysis of caustic lime, 7G ; new chlorine componnds, cS7 ; li(iue- fiictirm of chlorine, 9'i ; discovery of henzol, 94; suljiho-naphthtilic acid, 10(1 Clieiiiistry, How to cxiuiiine in, 277 Children and Faraday, 2IJ3, 235 Chlorine, Liquefaction of, oo, 91 Christmas lectures, 33, 37, 01, 101, 233, 234, 235, 258 City Philosophical Societ}^, 14, 10, 40, 41, 230 Clerk Maxwell, J. : article on Faraday, 135; theoiy of con- iluctiun, 155 ; electromagnetic theory of light, 199 : on Fara- day's conception of electric action, 217 ; letter to, on mathe- matics, 281 Closing daj's of Faraday's life, 259 Coinage of new words, 116, 143, 144, 103, 188, 205 Commonplace hooks, 40, ^9 Conduction, Theory of, 155 Conservation of energy, 167, 219 Contact theory of cells, 168 Continent, Visits to, 16, 17, 74, 224 Controversy, Detestation of, 268 Convolutions of the forces of nature, 167, 172, 269, 270 Copper disc experiment, 113 Criticism, Uses of, 14, 231, 240, 269 Crosse, Mrs. A., Keniiniscenccs of, 233, 215, 270 Crystallisation in relation to electric properties, 166, 167 Crystals in the magnetic field, 200, 202 Current, Conception of a, 146, 163 Cutting the magnetic lines, 134, 213 Crookes, Sir W., Advice to, 267 D. Dalton, John, 65, 226 Dance, Mr., gives Faraday tickets, 8 ; message to, 30 Daniell, Prof. J. F., 61 Davy, Sir Humphry : lectures of, 8, 36, 227 ; note to Faraday, II ; engages Faraday, 12 ; travels abroad, 17; his aristocratic lean- ings, 25 ; researches on electric arc, 37 ; invention of safety lamp, 37, 42, 209 ; writes to Faraday, 41. 45 ; misunderstand- ing with, 50 ; his jealousy of Faraday, oG, 59 ; his electro- magnetic discovery, 80 ; and the liquefaction of chlorine, 93 Davy-Faraday laboratory, The, 36 Do ia Rive, Auguste, 29, 6f;, 105, 237; letters to, 29, 185 — , Gustavo, 20, 28, 110, 141 ; letters to, 83, 85, 91, 207, 207 De la Rue, Warren: his lecture, 39; his eclipse photogiTiphs, 219 Diamagnetic, A, 179 polarity, 192, 210 Diamagnetism, Discovery of, 180 Dielectric medium, 153, 159, 163 Diploma-book, 271 Discharge, electric, Forms of, 137, 102 , Dark, 102 Discoveries, Value of, 63, 224, 248 Disijlacement currents, 166 Doctrine of conservation of energy, 167, 219 of correlation of forces, 172, 269, 270 of electrons, 148 Domestic affairs, 49, 69, 244, 257 Doubtful knowledge. Aversion for, 46, 92 _ Dry rot in timber, 149 INDEX. 803 Dumas: Reminiscences "by, 20, o9, 240 ; and Araii-o's copper, 106 ; discover}' of oxalamide, I'iT E. Eddy-currents, Eil'ccts due to, 107, ly'l, 2(14 Education, Views on, 278 Eel, The electric, 167 Electric light for lighthouses, 21S, 269 Electrical machine, Faraday's own, 6 — — , The "new," 121 Electrocheraicallaws, 141, 147 Electrodes, 143 Electrolysis, 143 Electrolytes, 143 Eiectromagnetic rotations discov- ered, ol, 83. 87 Eleoti'umaguctism, Fouudatious of, 77 Electrons, Doctrine of, 148 Electrotouic state, 116, ]26, 160, 21o Elocution, Lessons in, 43, 230 Enthusiasm, 15, 89, 225, 240 Ether, The (ire TEther) Evolution of electricity frrun mag- netism, 108, 114 Examinations in chemistry, 277 Experiment, Love of, 117, 230, 276 the touchstone of hj'pothesis, 221 ■ rtr.si'.s mathematics, 117, 239, 280 Exj)talmental researches in elec- tiicity and magnetism : the tirst series, 113 ; the last series, 216 ; Clerk Maxwell on, 218 Fxpertwork, 51, 61, 63, 274 Explosions iu the laboratory, 94 F. Faraday, James, 1, 2, 224 ~, Michael : born, 1 ; scltooling of, 2 ; goes as errand boy, 3 : apiirenticed as bookbinder and stationer, 5 ; journeyman book- binder, 9 ; attends Tatum's lectures, 6 ; attends Sir H, Davy's lectures, 8 ; acts as Davy's amanuensis, 10 ; engaged at Koyal Institution, 12; his foreign tour with Davy, 16 ! visits Paris, 18; visits Florence, 21 ; visits Geneva, 22, 28 ; returns to Royal Institution, 34 ; lectures at City Philosophical Society, 40, 43 ; loyalty to Davy, 42, 5U, 269 ; begins original work, 46 ; falls in love, 46 ; his poem to Miss Barnard, 46 ; his wedding, 49 ; made . superintendent of laboratory, 49, 98 ; discovers electromagnetic rotations, 51 ; elected F.R.S., 59 ; made D.C.L. of Oxford, 65 ; awarded Cojolej^ Medal, 69 ; declines professor- ship in London Univer.sity, 66 ; receives a pension in Civil List, 72 ; appointed adviser to Trinity House, 67 ; axjpointed elder in Sandemanian church, 293 ; dis- covers magneto- electric induc- tion, 112, 115; discovers mag- neto-riptic rotation, 176 ; discovers diamagnetism, 186 ; readmitted to Sandemanian church, 297 ; exposes spiritualistic jthenomcna, 250 ; declines Presidency of Royal Society, 255 ; declines presidency of Royal Institution, 255 : resigns professorship at Royal Institution, 259 ; resigns advisership to Trinity House, 259; resigns eUlershii)in Sande- manian church, 259 ; decease and funeral, 260 -, Robert, 1, 2, 6, 249, 250 , Sarah (Mrs. Faraday), 49, 50, 51, 223, 225, 255, 257, 291 ; letters to, 47, 48, 52, 53, 256 Faraday's father, 1, 2, 224, 289 ^— mother, 1, 2, 12, 17, 22, 33, 41, 69, 289 Fatalism, 52, 288 Fees for professional work, 51, 61, 244, 274 Field, The magnetic; first use of this term, 188 Fishes, electrica-l, Researches rm, 2U, 139, 167 Fluids, Alleged electric and mag- netic, 212, 216, 218 Foreign travel, 16, 17, 74, 224 Fox, Caroline, Reroinisccuces of, 235 Frasef^s Magaz-uic and Faraday's pension, 72 304 MICHAEL FARADAV. Fresnel's amiouucement, lO.i Friday evenings at the Koval Institution, 33, 60, 100, 101, UW 166, 170, 192, 203, 21'J, 220, 22'). 232, 236, 259 Fuller, John, founds the FuUeriau professorships, 36 Funeral, 260 G. Gases. Liquefaction of. '>o. 91, 171 , Matjuetic properties of. 204, 20S Gassiot, J. P., Reminiscences hv. German lauc;uage. Views on the, 2S0 Gladstone, Dr. J. Hall. 60, 290 Glass, Researches on, 95 GlaSsiteS (.s-fC SiNDKlIANIiNS") Gold, Optical properties of, 219 Gra-\T.tj in relation to electricity, 204. "220. 2So — — , Speculations as to, 195, 203 Grove, SirWm., 263, 269 Gymnotus, 167 Incandescent electric lamps, 199 Income, 68, 215 Indignation against wrong, 227 Induced currents, 114 Induction (electromagnetic), Dis- coverj' of, 114 (electrostatic), or influence, 153 . Aleaniug of the term, 119 Inductive capacity, 159 Influence {.fcf Induction) Inner conflicts. 226, 290 Iodine, Davy's experiments on, 19, 21.27 Ions. (_)rigin of term, 144, 145 J. Jentiu, "Wm.. observes spark at break, 150, 243 -Tones (.svr Bence Jon'ks) Journals of foreign travel, IS, 224 Juvenile lectures at Roval Institu- tion, 33, 37, 61, 101, 233, 231, 235, 25S H. Hachette. Letter to, 266 Hampton Court, House at. 257, 25y Hare, R., Letter to, 269 Harris, Sir \V. Snow, 64, 26!) Heat, Effect of. on magnetism. 208 Heavv-glass, 100, 176 Helmholtz, Prof. H. von, 282, 283 Henry, Professor Joseph, Reminis- cence bv. 241 Herschel,' Sir John, 57, O^, 107, 116, 131, 262, 297 Home life, 49, 69, 223. 244. 257 Honours awarded to Faradav, 69, 199, 244. 255. 271 , scientific. Views on. 271 Hyjiotheses, Free use of. 221, 241 I. Ice a non-conductor. 140 , Regelation of, 219 Identity uf electricity from differ- ent sources, 137 Imagination, Use of the, 160, 227, 276 Kclile. Rev. J., and the hodge- pndgc of philosophers, 66 Kelvin, Lord : theory of electro- motive forces, 148 ; on theory of magnetic penneability in a?olo- tropic media, 201 ; on Faraday's views of electricity, 281; letter from, 285 Ken-, Dr. Johu : electro-optic dis- covery, 173; m^agueto- optic dis- covery, 182 Kindliness, 226 Kniglitliood no lionour, 273 Kuudt, Aug., magueto-optic dis- covery, 1S2 L. Laboratories at Albemarle Street. 36, 51. 66, 80, 84, 96 Lateral effects of cuiTeut, 151. 165, 170 Lectures at Royal Institution : Davy's, 8. 36; Faradav's tii-st, 227;" Juvenile. 33, 37, '61, 101, 233, 234, 235, 258 ; afternoon, 37, 166 , Friday night discourses, 33, INDEX. 805 00, 100. 101, 149, 166, 170, 192, 20;j, 219, -I'lO, '225, 232, 236, 2o9 Luctures at the Loudou Iii.'stitution 101 at the British Associatiou, 201- — — - at St. George's Hospital, 166 at Woolwich, GO, 101 •Lecturiug, Views about, 16, 226, 232, 238 Letters from Faraday to : Ahhott, B., 7, 9, 15, 22, 25, 26, 41, 44, 228 ; Andrews, T., 273 ; Baruard, Miss Sarah, 47, 48 ; Becker, Dr., 244; Burdett-Coutts, Baroness, 240; Davy, Sir H., 10; De la Rive, A., 29, 185; De la Rive, G., 83, 85, 91, 207, 267 ; Deacon, Mrs., 253 ; Faraday, Mrs., 52, 53, 256; Grove, Sir Wm., 263; Hare, R., 269; Lovelace, Lady, 291; Matteucci, Prof. C, 253, 262, 267 ; Melbourne, Lord, 71 ; Moore, Miss, 207 ; Mun-ay, Mr. John, 234; Paris, Dr. J. A., 10, 93; Percy, Dr. J. 253; Phillips, R., 61, 109, 114, 194, 270, 277; Riebau, G., 30; Royet, Dr. P., 99 ; Schonbeiu, Professor, 206 ; 252 ; the Deputy- Master of Trinitv House, 67 ; Tyndall, Prof. J., 210, 204, 268, 277, 278, 280 ; Whewell, Rev. W., 145 ; Young, Dr. T., 97 to Faraday : From Sir H. Davy, 44, 45 ; from Baron Liebig, 225 ; from Sir W. Thom- son (Lord Kelvin), 285; from Rev. W. Whewell, 116, 144, 145, 163, 205 Liebig, J. von, Reminiscences by, 224, 282 Light, Action of magnetism on, 176 , Electromagnetic theory of, 197, 199, 213 Lighthouses, Scientific work for, 67, 199, 218, 259 Lmes of force, 113, 133, 195, 208, 211, 213, 285; vibrations of, 195 Liquefaction of gases, 55, 91, 171 Loudou L^niversity {■•ice Uni- veesitt) Love of children, 233, 235 , Poetical diatribe against, and recantation, 40, 47 Lovelace, Lady, Letter to, 291 Love-letters of Faraday, 47, 48, 52, 53, 256 M. Magaecrystallic forces, 201 Magnetic lines, 113, 133, 195, 213, 214 Magnetisation by ligiit, 183 of light, 176 M;iguetism and cold, 167 ■ of gases, 204 ■ of rotation, Alleged, 106, 121 Magneto-electric discovery, 95, 112 induction, 115 — ^ light, 120, 130, 218, 250 machines, 122, 125, 126, 218, 259 Magneto -optical researches, 176, 182, 220 Magrath, E., 7, 14, 60, 231 Marcet, Mrs., Conversations on Chemistry, 6 Masquerier teaches Faraday to draw, 8 Mathematics vcraus experiment, 117, 239, 280 , Faraday's views on, 280, 281 and Faraday's methods, 217, 282 Matteucci, C, Letters to, 253, 262, 267 Maxwell {see Clkek Maxwell) Mayo, Herbert, Impromptu by, 117 Meat-canning processes, 243 Medium, Action in a, 157, 213, 216 - — , The part played by the, 128, 153, 158, 194, 213 Melbourne, Lord, and Faraday's Xaension, 69 Memory, Trouljles of a defective, 7, 63, 74, 253 Mental education, Views on, 278, 292 Models, Use of, 104, 239 Moigno, Abbe, Reminiscence by, 297 Moll, G. ; his electromagnets, 120 ; pamphlet on '^ Decline of Sci- ence," 110, 262 Moore, Miss, Letter to, 207 Morichini's experiments on mag- netisation by light, 21, 183 806 MICHAEL FARADAY. Murnhisou, Sir R., ReininisceiicG Music, Enjoyment of, 24ti N. Natural theolo<:^y. Views on, 208 Now electrical machine, 121 Newman, Rev. J. H., and the Bi'itish Association, Go Newton, Mr. Jos., Reminiscence l.y,;2ol Nobili and Antinori, their mistake, 266 Non-inductive winding, lol) Notebooks a better ti^st than examinations, 277 , Faraday's own, 8, 50, 73, 87, 90, 91, 108, 111, 118, 129, 141, US, loO, 15:j, ir)6, 167, 177, 180, 181, 182, 220 0. Oersted's discovery of electromag- netism, 77, 78 Optical glass, Research on, 9'), 100 — - illusions, Research on, 136 relations of electricity, 91, U9, 15-'), 167, 172, 174, 175 of magnetism, 17G, 182, 220 Order and method, 68, 99, 200 Owen, Lady, Reminiscences by, 236 Oxford and the philosophers, 61 Oxygen, Magnetic properties of. 208 Paris, Dr. J. A., Letters to, 10, 93 Passive state of iron, 167 Peel, Sir- Eobert, 69, 70, 246 Pension: declined, 71; accepted, 72 Percy, Dr. John, Letter to, 253 Permeability, Magnetic, in crystals, 201 , Research on, 206 Personal api^earauce, 4, 18, 74, 255 Phillips, Richard, 7, 44, 52, 54, 57, 59, 61, 84, 87, 193; letters to, 61, 109, 114, 194, 270, 277 Phosphorescence, Lectiu'es on, 136, 219 Pliieker, Julius: on magneto-optic action, 203 ; shows electric dis- charge, 240 Poetry by Faraday, 40, 47 Poisson : on Arago's rotations, 107; on magnetic theory, 201 Polar forces in crystals, 94, 20O, 202 Polemics in science hateful, 268 Poles are only doors, 141, 241 Politics, Indifference to, 19, 21, 33, 26S Pollock, Lady, Remiinsceuccs by, 235, 254, 25"7 Practic-al applications of science, 63, 216, 224, 248, 259 Preaching, Style of, 293 Preservation of Rai^hael's cartoons, 246 Prince Consort, H.R.H. the, 237, 257, 278 Principle of all dynamo machines, 216 Priority in discovery, 265 Professional work tor fees, 51, 61, 274 relinquished, 61 , 274, 275 Professorship of Chemistry at Uni- versity College, The, ijC), 277 ; declined, 66 Professorships at the Royal Institu- tion, 36 Prop'irtional judgment advocated, 242 Public Schools Commission, Evi- dence given before, 278 P/a/c/i, Caricature in, 252 Pusey and science, 65 ■ Q. QKcirterli/ Journal of Sci.eticf\ 39, 46, 75,^76, 82, 88, 92, 94, 104 Queen Victoria, 257, 297 P. Radiant matter, 40 Rain torpedo, The, 20 Ray-vibrations, Thoughts on, 103 Regelatiou of ice, 219 Reid, Miss, Reminiscenoes by, 223, 231 Eeligious belief, 51, 289, 291 INDEX. 307 ap- and Religious character, 71, 244, '245 Kemuueration of science, 44, (j8, 244, 274 Repulsions, magnetic, New, 190 Research, Royal Institution as place for, 37 unliamperotl hy other duties, Researches, Original : the foiu' degrees of, 241 ; Faraday's first, 70 ; Faraday's last, 220 ;" division into periods, 75 ; summary of. Residences :— Weymouth Street, 2 ; Royal Institution, 13, 68 ; Hamp- ton Court Cottage, 258 Retardation of discharge, 161 Riebau, George : Faraday's em- ployer, 3, 7, 22; Faraday prenticea to, 51 ; letters messages to, 29, 34 Ring, The famous experiment with the, 108 Rohinson, H. Crabb, Reminiscences by, 8, 236 Rontgen on displacement currents, 166 Rotation of plane of polarisation of light, 177 Rotations, electromagnetic, Dis- covery of, 51, S3, 87 Royal Institution : foundation of, 35 ; Davy's lectures at, 8, 36, 39 ; jtrecarious state of, 22, 29, 35, 36, 68 ; laboratories of, 36 ; lectures at the, 37, 166; Christ- mas lectures, 33, 37, 61, 101, 233, 234, 235, 258 ; Friday night meetings, 33, 60, 100, 101, 149, 166, 170, 192, 203, 219, 220, 225, 232, 236, 259 ; Presidency offered and declined, 255 Royal Society : first papers read to the, 52, 263 ; candidature for Fellowship in the, 5Q, 57, 50 ; Faraday's election as Fellow of the, 59 ; committee on optical glass, 95, 99 ; Member of Council, 136, 261 ; Presidency offered to him, 255, 263 ; dissatisfaction with, 262 Ruhmkorff's induction-coil, 219, 225 ' Rumford, Benjamin Count of : founds the Royal Institution, 35 ; Faraday dines with, 34 Sacrifice for Science, 6d, 01, 231, 244 Safety-lamp ; Faraday aids Davy to invent the, 42 ; controversy about, 269 Salaries paid to scientific men, 41, 68, 244, 274 Sandemauians, 4, 51, 286 Schoubein, Prof., Letters to, 200, 252 Science in education, 279 teaching, Views on, 278 . Scientific societies, 261 Scoffern, Dr., Anecdote by, 280 Self-induction investigated, 150, 151 Sermons, Faraday's, 293 Shaftesbury, Earl of, 60 Sirium, //ila.s Vestium, 46, 77 Sisters, His letters to his, 32 Smart, B. H,, teaches elocution, 43, 230 Snow-Harris {.siT IliEitis) Social character, 245 Society of Arts, 14 Source of electromotive force in cell, 168 South, Sir James, 0, 57, 69, 70, 97, 262 Spark from a magnet, 64, 119, 130 Specific inductive capacity, 159 Spiritualists, Opinion of, 251 Steel, Research on, 82 Stinginess of British Government towards science, 274 Sturgeon, W. : his invention of the electromagnet, 102, 226 ; on Arago's rotations, 107 Submarine cables, 161 Sunday observance, 24, 51, 55, 224, 295, 297 Table-turning explained, 251 Tatum's lectures, 0, 14 Testimonials of candidates, Repug- nance to, 277 Thames impurities, 252 Thomson, Sir W. {see Kelvin) Thoughts on ray-vibrations, 193 Thunderstorms enjoyed, 240 Time of propagation of magnetism, 220, 284 308 MICHAEL FARADAY. Toronto, what its university might have been, 277, 278 Torpedo, The, 20 Trinity House, Scientific adviser to, 67, 199, 218, 259 Tubes of force, 211 Turner, J. W, M., R.A., Advice to, about pigments, 2-46 Tyndall, I'rof. : reminiscences Tiv, 4, 49, 7i, 175, 187, 225, 255, 290, 296, 299 ; his ■' Faraday as a Dis- coverer," 4, 130, 157, 169, 202; letters to, 210, 264, 268, 277, 278, 280 TJ. Utihty oe discoveries, 63, 224, 248 University College, Professorship in, 66, 277 University of London : Senator of, 275 ; degrees in science, 275 y. Varley, Cornelius, 5, 294 Velocipede riding, 74 Vesuvius, Ascents of, 22, 33 Vibrations, Thoughts oura}'-, 193 Visits to the sick, 245, 296 Volta, Count Alessandro, Meeting with, 22 Volta-electric induction, 115 * Voltameter, 146 "VV. Water, On freezing of, 203 Wellington, The Duke of, on prac- tical application of discovery, 248 Wheatstone, Sir Charles : on velo- city of (.Uscharge, 149, 161 ; his electric chronoscope, 192 Whewell, Rev. 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