Voltaic Electricity on Alcohol, Sfc. 337 



necessarily conducted into it, by a train of investigation which, 

 in its origin, had no reference to this particular part of the in- 

 quiry. 



From the important aid which Mr Faraday's principle of the 

 direct connection between the quantity and chemical action of 

 an electric current, is capable, if well founded, of affording, in 

 determining such questions as I had in view, this principle was, 

 of course, one of my chief subjects of examination ; and I found 

 it necessary to endeavour to satisfy myself, in so far as regarded 

 solutions, how far the evidence was sufficient to establish that 

 the chemical action of an electric stream is proportional to the 

 absolute quantity of transmitted electricity, and that a given 

 quantity of electricity will decompose a chemical equivalent of 

 the substances on which it acts. 



For the purpose of bringing these principles to the test of ex- 

 periment, Mr Faraday has employed an arrangement to which 

 he gives the name of the Volta Electrometer, of which there are 

 several modifications, but all of them depending on the principle 

 that the hydrogen and oxygen evolved from water under decom- 

 position by a given electric current, are collected, and measured, 

 and compared with the same or different elements, as the case may 

 be, separated from the same or a different substance, which is un- 

 der decomposition by the same electric stream.* Now, I have 

 had ample opportunities of confirming experimentally the truth of 

 the above law, in so far as regards water, and have no doubt what- 

 ever that the same current of electricity will always decompose the 

 same absolute quantity of water, when it exerts its decomposing 



* It is only doing justice to MM. Gay Lussac and Thenard to remember, 

 that they long ago employed the quantity of the gases evolved by water under the 

 agency of the voltaic current as a measure of its chemical effects (Recherch. Phys. 

 Chim., Part i.) They did not, however, compare this quantity with other effects 

 produced by the same current at the same time. 



