300 HISTORY OF CHEMIfal'KY. 



the progress of science, the generalizations of one generation are absorb 

 ed in the wider generalizations of the next. 



But in order to reach securely this wider generalization, 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 preceding philoso- 

 phers had maintained, that the current 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, pro- 

 duces, when the circuit is completed, a current of electric influence in 

 the wire ; and this current, if it pass through an electrolyte, manifests 

 itself by decomposition, overcoming the chemical affinity which there 

 resists it. An electrolyte cannot conduct without being decomposed. 

 The forces at the point of composition and the point of decomposition 

 are of the same kind, and are opposed to each other by means of the 

 conducting-wire ; the wire may properly be spoken of " as conducting 

 chemical affinity : it allows two forces of the same kind to oppose one 

 another ; electricity is only another mode of the exertion of chemical 

 forces ;" and we might express all the circumstances of the voltaic pile 

 without using any other term than chemical affinity, though that of 

 electricity may be very convenient. 28 Bodies are held together by a 

 definite power, which, when it ceases to discharge that office, may be 

 thrown into the condition of an electric current. 39 



Thus the great principle of the identity of electrical and chemical 

 action was completely established. It was, as Faraday with great 

 candor says, 30 a confirmation of the general views put forth by Davy, 

 in 1806, and might be expressed in his terms, that "chemical and 

 electrical attractions are produced by the same cause ;" but it is easy 

 to see that neither was the full import of these expressions understood 

 nor were the quantities to which they refer conceived as measurable 

 quantities, nor was the assertion anything but a sagacious conjecture, 

 till Faraday gave the interpretation, measure, and proof, of which we 

 have spoken. The evidence of the incompleteness of the views of his 

 predecessor we have already adduced, in speaking of his vague and incon- 



Researches Art. 918. 2T 915. 2e 917. 29 855. 3 " 965. 



