162 Dr. Faraday's Experimental Researches in Electricity, 



&c, or more cautiously, that it determines their evolution 

 upon the surface ; and that the negative pole acts in an equal 

 manner upon hydrogen, combustibles, metals, and bases. 

 According to my view, the determining force is not at the 

 poles, but within the decomposing body ; and the oxygen and 

 acids are rendered at the negative extremity of that body, 

 whilst hydrogen, metals, &c, are evolved at the positive ex- 

 tremity (518. 524.*). 



662. To avoid, therefore, confusion and circumlocution, and 

 for the sake of greater precision of expression than I can other- 

 wise obtain, I have deliberately considered the subject with two 

 friends, and with their assistance and concurrence in framing 

 them, I purpose henceforward using certain other terms, 

 which I will now define. The poles, as they are usually called, 

 are only the doors or ways by which the electric current 

 passes into and out of the decomposing body (556.); and they 

 of course, when in contact with that body, are the limits of its 

 extent in the direction of the current. The term has been 

 generally applied to the metal surfaces in contact with the 

 decomposing substance ; but whether philosophers generally 

 would also apply it to the surfaces of air (465. 471.) and 

 water (493.), against which I have effected electro-chemical 

 decomposition, is subject to doubt. In place of the term pole, 

 I propose using that of Electrodef, and I mean thereby that 

 substance, or rather surface, whether of air, water, metal, or 

 any other body, which bounds the extent of the decomposing 

 matter in the direction of the electric current. 



663. The surfaces at which, according to the common 

 phraseology, the electric current enters and leaves a decom- 

 posing body, are most important places of action, and require 

 to be distinguished apart from the poles, with which they are 

 mostly, and the electrodes, with which they are always, in 

 contact. Wishing for a natural standard of electric direction 

 to which I might refer these, expressive of their difference 

 and at the same time free from all theory, I have thought it 

 might be found in the earth. If the magnetism of the earth 

 be due to electric currents passing round it, the latter must 

 be in a constant direction, which, according to present usage of 

 speech, would be from east to west, or, which will strengthen 

 this help to the memory, that in which the sun appears to 

 move. If in any case of electro-decomposition we consider 

 the decomposing body as placed so that the current passing 

 through it shall be in the same direction, and parallel to that 

 supposed to exist in the earth, then the surfaces at which the 



* These numbers, and others referred to in these Researches from 450. 

 to 563., both inclusive, belong to the Fifth Series, noticed in our third 

 volume, as already stated. — Edit. 



"|" f)MxTf>ou t and 6^o( a way. 



