EPOCH OF DAVY AND FARADAY. 187 



trometer, Faraday obtained, for each elementary 

 substance, a number which represented the relative 

 amount of its decomposition, and which might pro- 

 perly 24 be called its "electro-chemical equivalent." 

 And the question naturally occurs, whether these 

 numbers bore any relation to any previously esta- 

 blished chemical measures. The answer is remark- 

 able. They were no other than the atomic weights 

 of the Daltonian theory, which formed the climax 

 of the previous ascent of chemistry ; and thus here, 

 as everywhere in the progress of science, the gene- 

 ralizations of one generation are absorbed in the 

 wider generalizations of the next. 



But in order to reach securely this wider gene- 

 ralization, Faraday combined the two branches of 

 the subject which we have already noticed; the 

 theory of electrical decomposition with the theory 

 of the pile. For his researches on the origin of 

 activity of the voltaic circuit (his Eighth Series), led 

 him to see more clearly than any one before him, 

 what, as we have said, the most sagacious of pre- 

 ceding philosophers had maintained, that the cur- 

 rent in the pile was due to the mutual chemical 

 action of its elements. He was led to consider the 

 processes which go on in the exciting-cell, and in 

 the decomposing place, as of the same kind, but 

 opposite in direction. The chemical composition of 

 the fluid with the zinc, in the common apparatus, 

 produces, when the circuit is completed, a current 

 24 Art. 792. 



