348 Mr Connell on the Action of 



with this particular view, and therefore am not entitled to make 

 any other observations on Mr Faraday's researches on them, 

 than to observe that many of the experiments, particularly those 

 with the chlorides and iodides of lead (814, 818, 794), the chlo- 

 ride of tin (819, 789), and the borate of lead (799), undoubtedly 

 appear to lead to the establishment of this highly important 

 principle with respect to other bodies than water. 



We must, however, take care that we do not extend our ideas 

 of this definite action farther than any of the experiments which 

 have been adduced in support of it by its author will warrant, a 

 misconception into which I have reason to believe that some who 

 have not fully considered the evidence have fallen. One limit 

 to it has been set, on the ground that the electric action itself is 

 supposed to be capable of decomposing such bodies only as are 

 composed of the same, or at least a like number of atoms of their 

 elements, a point to which I shall presently advert. Accordingly 

 there are no grounds whatever for holding that any definite 

 action applies to such bodies as the great class of oxyacids and 

 many other substances, admitted on all hands to consist of an 

 unequal number of elementary atoms, and if such bodies are 

 really undecomposable, no such definite action of course is pos- 

 sible. But, farther, there is as yet no evidence of the applica- 

 tion of definite voltaic action to the extensive class of ordinary 

 salts consisting of an acid and an alkali, and yet many of them 

 are composed of a like number of chemical equivalents, and are 

 undeniably subject to electric decomposition. According to the 

 experiments hitherto made, the protoxides, water included, and 

 the principal haloid salts, are the chief examples of the applica- 

 tion of the law, and for this reason, that these are the principal 

 substances on which the voltaic current operates. 



The point to which I have just alluded, whether the decom- 

 posing agency of the electric fluid reaches only to substances 

 composed of a like number of elementary atoms, is second only 

 in importance to the law of definite action, and would require 



