EPOCH OF DAVY AND FARADAY. 177 



the phenomena were altogether chemical in their 

 nature. He had already conjectured 4 , in 1802, that 

 all decompositions might be polar ; that is, that in 

 all cases of chemical decomposition, the elements 

 might be related to each other as electrically posi- 

 tive and negative; a thought which it was the 

 peculiar glory of his school to confirm and place in 

 a distinct light. At this period such a view was far 

 from obvious; and it was contended by many, on 

 the contrary, that the elements which the voltaic 

 apparatus brought to view, were not liberated from 

 combinations, but generated. In 1806, Davy at- 

 tempted the solution of this question ; he showed 

 that the ingredients which had been supposed to be 

 produced by electricity, were due to impurities in 

 the water, or to the decomposition of the vessels ; 

 and thus removed all preliminary difficulties. And 

 then, as he says 5 , "referring to my experiments of 

 1800, 1801, and 1802, and to a number of new 

 facts, which showed that inflammable substances 

 and oxygen, alkalies and acids, and oxidable and 

 noble metals, were in electrical relations of positive 

 and negative, I drew the conclusion, that the com- 

 binations and decompositions by electricity mere 

 referrible to the law of electrical attractions and 

 repulsions? and advanced the hypothesis, "that 

 chemical and electrical attractions were produced 

 by the same cause, acting in the one case on parti- 



4 Phil. Trans. 1826 5 Ib. 1826, p. 389. 



VOL. Ill, N 



