EPOCH OF DAVY AND FARADAY. 183 



preparatory step towards further investigation, to 

 show the identity of voltaic and animal electricity 

 with that of the electrical machine ; and as machine 

 electricity differs from the other kinds in being suc- 

 cessively in a state of tension and explosion, instead 

 of a continued current, Mr. Faraday succeeded in 

 identifying it with them, by causing the electrical 

 discharge to pass through a bad conductor into a 

 discharging-train of vast extent; nothing less, indeed, 

 than the whole fabric of the metallic gas-pipes and 

 water-pipes of London. In this Memoir 11 it is easy 

 to see already traces of the general theoretical 

 views at which he had arrived; but these are not 

 expressly stated till his "Fifth Series;" his inter- 

 mediate Fourth Series being occupied by another 

 subsidiary labour on the conditions of conduction. 

 At length, however, in the Fifth Series, which was 

 read to the Royal Society in June 1833, he ap- 

 proaches the theory of electro-chemical decomposi- 

 tion. Most preceding theorists, and Davy amongst 

 the number, had referred this result to attractive 

 powers residing in the poles of the apparatus ; and 

 had even pretended to compare the intensity of this 

 attraction at different distances from the poles. By 

 a number of singularly beautiful and skilful expe- 

 riments, Mr. Faraday shows that the phenomena 

 can with no propriety be ascribed to the attraction 

 of the poles 12 . " As the substances evolved in cases 

 of electro-chemical decomposition may be made to 



11 Phil. Trans. 1833. 12 Researches, Art. 497. 



