384 THEORY OF GALVANIC, 



which causes sulphuric acid to combine with 

 copper, making a transparent solution of copper, 

 causes the same acid to combine with the plates 

 of the voltaic battery, by which they are oxi- 

 dized and dissolved, when a portion of the latent 

 caloric of the acid is given out in the concen- 

 trated form of electricity, conducted from the 

 plates by the connecting wires, and thence to 

 the extremities of the battery. 



I have already shown that sulphuric acid is 

 composed of oxygen, sulphur and caloric that 

 nitric acid is composed of oxygen, nitrogen and 

 caloric and so of other compounds. When solu- 

 tions of nitric, sulphuric, or hydro-chloric acids 

 are poured upon metals, there is a rapid transition 

 of caloric from the acids to the metals, by which 

 they are made to combine chemically, with 

 great diminution of volume, and evolution of 

 heat. When they are poured on copper and 

 zinc filings, they are decomposed, and the metals 

 oxidized still more rapidly. But when the 

 same metals are arranged in the form of a gal- 

 vanic battery, and immersed in the same solu- 

 tions, electricity is evolved : from which it would 

 seem to follow, that the latent caloric of acids 

 is given out in the form of calorific or electric 

 power, according to the mode of its disen- 

 gagement. 



Another fact of fundamental importance to a 



