104 ON THE HEAT EVOLVED DURING 
to its reaction is rendered latent and is thus lost 
by the circuit. 
3rd. Hence it is that however we arrange the 
voltaic apparatus, and whatever cells of electro- 
lysis we include in the circuit, the whole caloric 
of the circuit is exactly accounted for by the whole 
of the chemical changes. 
4th. As was discovered by Faraday, the guan- 
tity of current electricity depends upon the num- 
ber of atoms which suffer electrolysis in each cell : 
and the intensity depends upon the sum of che- 
mical 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 me- 
chanical and heating powers of a current are 
proportional to each other. 
5th. The magnetic electrical machine enables 
us to convert mechanical power into heat, by 
means of the electric currents which are induced 
by it. And TI have little doubt that by interposing 
an electro-magnetic engine in the circuit of a bat- 
tery, a diminution of the heat evolved per equi- 
valent of chemical change would be the conse- 
