GALVANIC ELECTRICITY. 379 



copper, the direction of the current is reversed. 

 Copper is positive in relation to lead in nitric 

 acid, which oxidizes the former most rapidly ; 

 whereas, in dilute nitric acid, by which the lead is 

 most speedily dissolved, the lead is positive. He 

 found that even two plates of copper, when im- 

 mersed in solutions of the same acid, but of 

 different strength, form a voltaic circle, the plate 

 on which chemical action is most energetic, 

 giving a current of positive electricity to the 

 other and that a compound circle might be 

 formed solely of zinc plates and one acid, pro- 

 vided the same side of each plate be more 

 rapidly oxidized than the other. 



The following experiments are decisive against 

 the theory of Volta. M. Delarive ascertained 

 that when zinc and copper plates were brought 

 in contact in an atmosphere of hydrogen or 

 nitrogen, wholly deprived of oxygen, moisture, 

 and other bodies, no electricity was evolved ; 

 and when he purposely increased chemical action 

 by exposing the zinc to acid fumes, or by substi- 

 tuting for zinc a more oxidable metal, such as 

 potassium, the electrical effects observed, on 

 contact with copper, were greatly augmented, 

 the amount being in proportion to the chemical 

 action. (Ann. de Chim. et de Phys. XXXVIII. 

 et IX.) 



The above facts have an important bearing on 

 the general theory of electricity ; for they seem 



