EPOCH OF DAVY AND FARADAY. 175 



to speak as if I were removed by centuries from the 

 personages of my story. 



The phenomena observed in the Voltaic appara- 

 tus were naturally the subject of many speculations 

 as to their cause, and thus gave rise to " Theories of 

 the Pile." Among these phenomena there was one 

 class which led to most important results : it was 

 discovered by Nicholson and Carlisle, in 1800, that 

 water was decomposed by the pile of Volta ; that is, 

 it was found that when the wires of the pile were 

 placed with their ends near each other in the fluid, 

 a stream of bubbles of air arose from each wire, and 

 these airs were found on examination to be oxygen 

 and hydrogen; which, as we have had to narrate, 

 had already been found to be the constituents of 

 water. This was, as Davy says 1 , the true origin of 

 all that has been done in electro-chemical science. 

 It was found that other substances also suffered a 

 like decomposition under the same circumstances. 

 Certain metallic solutions were decomposed, and 

 an alkali was separated on the negative plates of 

 the apparatus. Cruickshank, in pursuing these 

 experiments, added to them many important new 

 results; such as the decomposition of muriates of 

 magnesia, soda, and ammonia by the pile ; and the 

 general observation that the alkaline matter always 

 appeared at the negative, and the acid at the posi- 

 tive, pole. 



Such was the state of the subject when one who 



1 Phil. Trans. 1826, p. 386. 



