334 Dr. Faraday's Experimental Researches in Electricity. 



bodies which have never, I believe, been even attempted to be 

 measured, such as the intensity of odours, &c. ; for this prin- 

 ciple seems to have a general application. We may always 

 find means of dividing the experiment into minute intervals 

 of time, and we may cause that quality of the body which 

 we wish to estimate the intensity of to act upon our senses 

 or upon our instruments, only during a certain number of 

 those intervals, but regularly and rapidly recurring in a stated 

 order. 



XLV. Experimental Researches in Electricity. — Seventh 

 Series. By Michael Faraday, D.C.L. F.R.S. Fullerian 

 Prof. Chem. Royal Institution, Corr. Memb. Royal and Imp. 

 Acadd. of Sciences, Paris, Petersburgh, Florence, Copenhagen, 

 Berlin, fyc. 



[Continued from p, 264.] 



If vii. On the definite Nature and Extent of Electro-chemical 

 Decomposition. 



783. TN the third series of these Researches, after proving 

 -*■ the identity of electricities derived from different 

 sources, and showing, by actual measurement, the extraor- 

 dinary quantity of electricity evolved by a very feeble voltaic 

 arrangement (371. 376.), I announced a law, derived from 

 experiment, which seemed to me of the utmost importance to 

 the science of electricity in general, and that branch of it de- 

 nominated electro-chemistry in particular. The law was ex- 

 pressed thus: The chemical power of a current of electricity is 

 in direct proportion to the absolute quantity of electricity 

 which passes (377.)» 



784. In the further progress of the successive investigations, 

 I have had frequent occasion to refer to the same law, occa- 

 sionally in circumstances offering powerful corroboration of its 

 truth (456.504.505.); and the present series already supplies 

 numerous new cases in which it holds good (704. 722. 726. 732.). 

 It is now my object to consider this great principle more 

 closely, and to develope some of the consequences to which it 

 leads. That the evidence for it may be the more distinct and 

 applicable, I shall quote cases of decomposition subject to as 

 few interferences from secondary results as possible, effected 

 upon bodies very simple, yet very definite in their nature. 



785. In the first place, I consider the law as so fully esta- 

 blished with respect to the decomposition of water, and under 

 so many circumstances which might be supposed, if anything 

 could, to exert an influence over it, that I may be excused 



