REFERENCE TO ROGET AND FARADAY. I 89 



has added a note containing an extract from Roget's work 

 in which the same views are expressed ; and there can be 

 little doubt (as was pointed out to the Author, by Mr. F. J. 

 Faraday) that it was these paragraphs to which Joule 

 referred, as they appeared in the Phil. Trans., 1840, and 

 in the reprint, Vol. II., 1844. How Joule managed to 

 misinterpret them is difficult to conceive, except that with 

 his mind full of his own view of " force," he seized the 

 view expressed as to the impossibility of creating "force " as 

 implying views as to the impossibility of its annihilation. 

 That Joule, with his clear insight as to the indestructibility 

 of "force," as he conceived it, was yet blind to the truth of 

 the universal destructibility of "force" as then generally 

 understood, is shown by the many arguments against 

 Carnot's expression of the law of this destructibility in 

 which the passage occurs. And misunderstanding the truth 

 in Carnot's views, it seems possible that he may have 

 interpreted views which, as expressed, were in strict accord- 

 ance with Carnot's, as being directly adverse, and in favour 

 of his own. 



Extract from Faraday's " Experimental Researches in Elec- 

 tricity" 2071 and 2073, with note to 2071 : — 



"The contact theory assumes, in fact, that a force which is 

 able to overcome a powerful resistance, as for instance that 

 of 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 with- 

 out any change in the acting matter or the consumption of 

 any generating force, a current can be produced which shall 

 go on for ever against a constant resistance, or only be 

 stopped as in the voltaic trough by the ruins which its exer- 



