418 Prof. A. de la Rive's Memoir of 



we ought to speak of certain of Faraday's theoretical ideas rela- 

 ting to general physics, and more especially to the nature of the 

 forces, and. their correlation to each other and to the essence 

 of matter ; but we prefer not to discuss the opinions emitted 

 by him upon these questions until after the exposition of his 

 works on electricity and magnetism. We must, however, at 

 once admit that his views on these matters are very contestable,' 

 and that, if they inspired him to make experimental researches 

 of the highest interest, this is a proof that, in the hands of a 

 man of genius, even a bad theory may be the origin of the most 

 beautiful discoveries. 



II. 



I pass now to the examination of those works of Faraday which 

 relate to electricity and magnetism. It is not without embarrass- 

 ment that I approach this examination ; for these researches are so 

 numerous that it would be necessary to extend this notice beyond 

 all bounds in order to give only a simple analysis of them ; and 

 they are at the same time so varied, that it is impossible to ex- 

 plain them in the chronological order of their publication without 

 confusion being the result. Thus, for example, the researches 

 on induction are interrupted by others on electrochemical decom- 

 positions, to be afterwards resumed and completed. Each me- 

 moir certainly forms a complete whole ; but one memoir is most 

 frequently followed by another the subject of which is quite dif- 

 ferent. It seems as if the author, after having treated one ques- 

 tion, found it necessary to recollect himself before resuming it, 

 and to divert his mind from it, so to speak, by taking up some 

 other kind of work. 



It has therefore appeared to me that the best thing for me to 

 do was to group all these various works under a few distinct 

 heads, so as to be able to give their essence without requiring to 



X enter into too many details. The first would include all the re- 



searches relating to electrochemistry; the second those which 

 have for their object induction, whether electrodynamic or elec- 

 trostatic ; and the third the phenomena relating to the action 

 of magnetism and dynamic electricity upon light and upon 

 natural bodies in general. It is true that there are some works 

 which elude this classification, as they will not enter into any 

 one of our three divisions. But these are less important works, 

 and such as were produced as occasions offered ; that is to say, 

 they are the fruit of some particular circumstance which attracted 

 Faraday's attention to some special point. Such is, for example, 

 the memoir which has for its object the investigation of the elec- 

 trical properties of the Gymnotus, — and that devoted to the evo- 

 lution of electricity by the friction exerted against solid bodies 



Q 



