294 HISTORY OF CHEMISTRY. 



water, or other substance in which the two wires are plunged, be 

 separated into two portions, provided these portions are connected by 

 muscular or other fibres. This use of muscular fibres was, probably, 

 a remnant of the original disposition, or accident, by which galvanism 

 had been connected with physiology, as much as with chemistry. Davy, 

 however, soon went on towards the conclusion, that the phenomena 

 were altogether chemical in their nature. He had already conjectur- 

 al, 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 positive 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 combina 

 tions, but generated. In 1806, Davy attempted the solution of this 

 question ; he showed that the ingredients which had been supposed to 

 be produced by electricity, were clue to impurities in the water, or to 

 the decomposition of the vessel ; and thus removed all preliminary 

 difficulties. And then he says, 5 " referring to my experiments of 1800, 

 1801, and 1802, and to a number of new facts, which showed that in- 

 flammable 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 combinations and decompositions by electricity 

 were 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 particles, in the 

 other on masses ; . . . and that the same property, under different modi- 

 fications, ^vas the cause of all the phenomena exhibited by different 

 voltaic combinations" 



Although this is the enunciation, in tolerably precise terms, of the 

 great discovery of his epoch, it was, at the period of which we speak, 

 conjectured rather than proved; and we shall find that neither Davy 

 nor his followers, for a considerable period, apprehended it with that 

 distinctness which makes a discovery complete. But in a very short 

 time afterwards, Davy drew great additional notice to his researches 

 .by effecting, in pursuance, as it appeared, of his theoretical views, the 

 decomposition of potassa into a metallic base and oxygen. This was, 

 as he truly said, in the memorandum written in his journal at the 



4 Phil. Trans. 182 '.. 6 Ib. 1826, p. 38!) 



