516 JAMES CLERK MAXWELL. 



intervening medium. But any view, whether the arguments 

 in its favour are conclusive or not, is of value if it lead us 

 to inquire more closely into the mechanism by which a 

 phenomenon is brought about ; and thus Faraday's concep- 

 tion of lines of force, transmitted through a medium, and 

 exerting tension and pressure wherever they are to be found, 

 are of more value as an instrument of mental research than 

 Weber's Theory of Electro-magnetism, however perfect the 

 latter may be from a mathematical point of view. 



The following quotation, from the preface to the Elec- 

 tricity and Magnetism, gives Maxwell's views of Faraday in 

 his own words : 1 



Before I began the study of electricity I resolved to read 

 no mathematics on the subject till I had first read through 

 Faraday's Experimental Researches on Electricity. I was aware that 

 there was supposed to be a difference between Faraday's way of 

 conceiving phenomena and that of the mathematicians, so that 

 neither he nor they were satisfied with each other's language. I 

 had also the conviction that this discrepancy did not arise from 

 either party being wrong. I was first convinced of this by Sir 

 William Thomson, to whose advice and assistance, as well as to 

 his published papers, I owe most of what I have learned on the 

 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 exhibited in the conventional form of mathema- 

 tical symbols. I also found that these methods were capable of 

 being expressed in the ordinary mathematical forms, and these 

 compared with those of the professed mathematicians. 



For instance, Faraday, in his mind's eye, saw lines of force 

 traversing all space where the mathematicians saw centres of 

 force attracting at a distance ; Faraday saw a medium where they 

 saw nothing but distance ; Faraday sought the seat of the pheno- 

 mena in real actions going on in the medium, they were satisfied 

 that they had found it in a power of action at a distance im- 

 pressed on the electric fluids. 



Suppose a small positively electrified body to start from 

 a point close to a positively electrified surface, and suppose 



1 See also Maxwell's article on "Faraday" in Ency. Brit., 9th edit. 



