CHAP. VII., 5.] 



ELECTRICITY. OERSTED DR FARADAY. 



179 



hammer has enumerated ahove 200 of his publica- 

 tions or articles, on a vast variety of subjects ; but 

 of all these, only a single tract of a few pages will 

 perhaps be ultimately remembered. As I before 

 remarked, his mind, though capable of continued 

 application, appears to have wanted the sort of con- 

 centration which prolonged physical researches re- 

 quire, and the school of philosophy in which he was 

 considered by his own countrymen as a proficient, has 



never been fruitful in researches based on Induc- 

 tion. 



In November 1850, the fiftieth anniversary of his (806.) 

 connection with the University of Copenhagen was His death, 

 celebrated by a jubilee. Though in his 74th year, 

 his activity was unimpaired, and he continued his 

 lectures and other employments until within a few 

 days of his death, which occurred on the 9th of March 

 1851, closing a life full of years and honour. 



5. DR FARADAY. Progress of the Theory of Electro-Chemical Decomposition Volta-Electric 

 Induction Magneto- Electricity Diamagnetism Optical Changes induced by Magnetism. 

 Professor Pliicker Magneoptic Action. 



(807.) 

 'Eminent 

 liscoveries 

 jfDrFara- 

 lay. 



(808.) 

 [lis early 

 iistory,and 

 sonnection 

 arith Davy 

 ind the 

 loyal In- 

 stitution. 



(809.) 

 (Variety of 

 ; iis publi- 

 hations 

 fiis Re- 

 [earchfs on 

 \Electricitu. 



Immeasurably the larger part of what we know 

 with regard to the nature and laws of electricity and 

 of its connection with Magnetism, so far as it has been 

 developed since the discovery of Oersted, is due to 

 the genius and perseverance of one man MICHAEL 

 FARADAY. 



This eminent philosopher was born, I believe, in 

 1791. He was originally " a bookseller's apprentice, 

 very fond of experiment and very averse to trade." 

 In 1812 he sent to Sir H. Davy, then at the height 

 of his reputation, a copy of a set of notes taken at his 

 lectures, desiring his assistance "to escape from trade, 

 and enter into the service of science." To the credit of 

 the popular and distinguished chemist, he gave Mr 

 Faraday a courteous answer, and appointed him as 

 chemical assistant in the Laboratory of the Royal In- 

 stitution in March 1813. Leaving England to travel 

 in the autumn of the same year, Davy engaged Mr 

 Faraday to accompany him as secretary and scien- 

 tific assistant; they returned in April 1815, and 

 from that time to the present Mr Faraday has 

 been constantly engaged in the scientific business 

 of the Royal Institution, which is as completely 

 associated with his numerous and splendid dis- 

 coveries as Cambridge is with those of Newton, 

 and Slough with those of the elder Herschel. By 

 a rare, perhaps unexampled good fortune, that esta- 

 blishment, founded principally for the promotion 

 of original research and the promulgation of dis- 

 coveries, has been indebted during the first fifty 

 years of its existence to the talents of two men only, 

 for a succession of new scientific truths which might 

 have done credit to a whole academy; indeed, if 

 to the names of Davy and Mr Faraday we add 

 that of Young, who here first promulgated the doc- 

 trines of the Interference of Light, there is scarcely 

 an academy in Europe which has within the same 

 period added so extensively to our choicest stock of 

 original science. 



Partly in consequence of his official duty of bring- 

 ing forward and explaining the most important cotem- 

 porary discoveries, partly also in consequence of his 

 own matchless talent of elucidating, by original illus- 

 trations, if not by new facts, whatever he undertakes 



to expound, the variety of subjects on which Dr Fara- 

 day has made essential additions to our knowledge 

 is so great that it is difficult to comprehend them 

 under one section. In conformity, however, with our 

 plan of suppressing minor facts, and insisting on the 

 most important, I shall confine myself to a summary 

 statement of his main discoveries connected with 

 Electricity and Electro-Magnetism as contained in a 

 continuous series of " Researches," published in the 

 Philosophical Transactions between 1831 and the 

 present time ; which, when collected (as they have 

 been in a distinct form), now fill three closely 

 printed octavo volumes. It would be difficult to 

 name in the history of any progressive experimental 

 subject so large an amount of research prosecuted 

 for so long a time in so methodical a manner and 

 with such remarkable uniformity in plan, and with 

 such unvarying success. 



I shall only farther premise that Dr Faraday's (810.) 

 earliest essays were naturally of a chemical charac- Electro- 

 ter. In 1820 he assisted Davy, in prosecuting Oe 

 sted's researches on the relations of Electricity and 

 Magnetism, and the following year he himself suc- 

 ceeded in producing, for the first time, the continuous 

 rotation of a magnet round an electric conductor, and 

 the converse rotation of the conductor round the 

 magnet (798). These experiments were the germ 

 of others which continued to interest philosophers as 

 well as the curious public for a long time after. But 

 it was in 1831 (when the author had attained his 40th 

 year) that the genius of Dr Faraday was displayed 

 in a commanding manner by the appearance of his 

 First and Second series of the Researches on Electri- 

 city, which have not perhaps been surpassed by even 

 the most brilliant of their successors. The subject was 

 the Induction of Electric Currents from other Currents 

 and from Magnets. But we shall find it most con- 

 venient to take an order different from that of the 

 discovery, and to present the main results of Dr 

 Faraday's electrical labours under the following Heads of 

 heads : his chief 



I. The law of definite Electro-chemical Decompo- 

 sition, and the theory of the pile connected therewith, 



II. The Induction of Electric Currents from other coveries. 



2 A 



