438 DR. FARADAY'S EXPERIMENTAL RESEARCHES IN ELECTRICITY. 



927. The general case (for it includes the former one (924.),) of acids and bases, 

 may theoretically be stated in the following manner. Let a, fig. 7. be supposed to 

 be a dry oxyacid, and h a dry base, in contact at c, and in electric communication 

 at their extremities by plates of platina p p, and a platina wire w. If this acid and 

 base were fluid, and combination took place at c, with an affinity ever so vigorous, 

 and capable of originating an electric current, the current could not circulate in any 

 serious degree ; because, according to the experimental results, neither a nor b could 

 conduct without being decomposed, for they are either electrolytes or else insulators, 

 under all circumstances, except to very feeble and unimportant currents (970. 986.). 

 Now the aflSnities at c are not such as tend to cause the elements either oi a ov h to 

 separate, but only such as would make the two bodies combine together as a whole ; 

 the point of action is, therefore, insulated, the action itself local (921. 947.), and no 

 current can be formed. 



928. If the acid and base be dissolved in water, then it is possible that a small 

 portion of the electricity due to chemical action may be conducted by the water 

 without decomposition (966. 984.) ; but the quantity will be so small as to be utterly 

 disproportionate to that due to the equivalents of chemical force ; will be merely in- 

 cidental ; and, as it does not involve the essential principles of the voltaic pile, it forms 

 no part of the phenomena at present under investigation*. 



929. If for the oxyacid a hydracid be substituted (927.), — as one analogous to the 

 muriatic, for instance, — then the state of things changes altogether, and a current due 

 to the chemical action of the acid on the base is possible. But now both the bodies 

 act as electrolytes, for it is only one principle of each which combine mutually, — as, 

 for instance, the chlorine with the metal, — and the hydrogen of the acid and the oxy- 

 gen of the base are ready to traverse with the chlorine of the acid and the metal of 

 the base in conformity with the current and according to the general principles already 

 so fully laid down. 



930. This view of the oxidation of the metal, or other direct chemical action upon 

 it, being the sole cause of the production of the electric current in the ordinary vol- 

 taic pile, is supported by the eflfects which take place when alkaline or sulphuretted 

 solutions (931. 943.) are used for the electrolytic conductor instead of dilute sul- 

 phuric acid. It was in elucidation of this point that the experiments without metallic 

 contact, and with solution of alkali as the exciting fluid, already referred to (884.), 

 were made. 



931. Advantage was then taken of the more favourable condition offered, when 

 metallic contact is allowed (895.), and the experiments upon the decomposition of 

 bodies by a single pair of plates (899.) were repeated, solution of caustic potassa 



* It will, I trust, be fully understood, that in these investigations I am not professing to take an account of 

 every small, incidental, or barely possible effect, dependent upon slight disturbances of the electric fluid during 

 chemical action, but am seeking to distinguish and identify those actions on which the power of the voltaic 

 battery essentially depends. 



