342 Literary and Philosophical Society. 



' 4th. As was discovered by Faraday, the quantity of 

 current electricity depends upon the number of atoms 

 which suffer electrolysis in each cell : and the intensity 

 depends upon the sum of chemical affinities. Now both 

 the mechanical and heating powers of a current are (per 

 equivalent of electrolysis in any one of the battery cells) 

 proportional to its intensity. Therefore the mechanical 

 and heating powers of a current are proportional to each 

 other. 



' 5th. The magnetic electrical machine enables us to 

 convert power into heat, by means of the electric currents 

 which are induced by it. And I have little doubt that by 

 interposing an electro-magnetic engine in the circuit of a 

 battery, a diminution of the heat evolved per equivalent of 

 chemical change would be the consequence, and this in 

 proportion to the mechanical power obtained. 1 



' I have shown also that the modus operandi is resistance 

 to conduction. 



' There are many phenomena which cannot be accounted 

 for by the theory which recognises heat as a substance ; 

 and there are several, which though sometimes adduced as 

 triumphant objections to the other theory, tend, when 

 rightly considered, only to confirm it. The heat of fluidity 

 may very naturally be regarded as the momentum, or 

 mechanical force necessary to overcome the aggregation of 

 particles in the solid state. The heat of vaporisation may 

 be regarded, partly as the mechanical force requisite to 

 overcome the aggregated condition of atoms in the fluid 

 state, and partly as the force requisite to overcome atmo- 

 spheric pressure. Again, the heat of combination is only 



1 I am preparing for experiments to test the accuracy of this proposition. 

 February 18, J. P. J. 



