so 



DR. FARADAY'S EXPERIMENTAL RESEARCHES IN ELECTRICITY. 



670. If this result was evident when water was supposed to be essential to, and 

 was present, in almost every case of such decomposition (472.), it is far more evident 

 now that it has been shown and proved that water is not necessarily concerned in 

 the phenomena (474.), and that other bodies much surpass it in some of the effects 

 supposed to be peculiar to that substance. ^ . 



671. Water, from its constitution and the nature of its elements, and from its fre- 

 quent presence in cases of electrolytic action, has hitherto stood foremost in this 

 respect. Though a compound formed by very powerful affinity, it yields up its ele- 

 ments under the influence of a very feeble electric current ; and it is doubtful 

 whether a case of electrolyzation can occur, where, being present, it is not resolved 

 into its first principles. 



672. The various oxides, chlorides, iodides, and salts (402.), which I have shown 

 are decomposable by the electric current when in the liquid state, under the same 

 general law with water, illustrate in an equally striking manner the activity, in such 

 decompositions, of elements directly and powerfully opposed to each other by their 

 chemical relations. 



673. On the other hand, bodies dependent on weak affinities very rarely give way. 

 Take, for instance, glasses : many of those formed of silica, lime, alkali, and oxide of 

 lead, may be considered as little more than solutions of substances one in another*. 

 If bottle-glass be fused, and subjected to the voltaic pile, it does not appear to be at 

 all decomposed (408.). If flint-glass, which contains substances more directly op- 

 posed, be operated upon, it suffers some decomposition ; and if borate of lead glass, 

 which is a definite chemical compound, be experimented with, it readily yields up its 

 elements (408). 



674. But the result which is found to be so striking in the instances quoted is not 

 at all borne out by reference to other cases where a similar consequence might have 

 been expected. It may be said, that my own theory of electro-chemical decomposition 

 would lead to the expectation that all compound bodies should give way under the 

 influence of the electric current with a facility proportionate to the strength of the 

 affinity by which their elements, either proximate or ultimate, are combined. I am 

 not sure that that follows as a consequence of the theory ; but if the objection be 

 supposed one presented by facts, I have no doubt it will be removed when we obtain 

 a more intimate acquaintance with, and precise idea of, the nature of chemical 

 affinity and the mode of action of an electric current over it (518. 524.) : besides which, 

 it is just as directly opposed to any other theory of electro-chemical decomposition as 

 the one I have propounded ; for if it be admitted, as is generally the case, that the 

 more directly bodies are opposed to each other in their attractive forces, the more 

 powerfully do they combine, then the objection applies with equal force to any of 

 the theories of electrolyzation which have been considered, and is an addition to those 

 which I have taken against them. 



* Philosopliical Transactions, 1830, p. 49. 



