OHM ON THE GALVANIC CTBCUIT. 491' 



the circuit which we have especially in view ; if we wish to 

 reduce this motive force of the circuit to the unit of surface, 

 we must divide that expression by the magnitude of the sec- 

 tion O). 



With respect to the causal relation between the law of electric 

 attractions and repulsions, and that of the diffusion of electricity, 

 or respecting the mutual dependence of the functions x. and 

 x' on each other, we will, for the present, not enter into any 

 further inquiries, as shortly an occasion will present itself for this 

 purpose. We will here content ourselves with the observation, 

 that the above mode of explanation has arisen from the endea- 

 vour to render the similarity of the mode of treatment in the 

 doctrines of electricity and heat very obvious. 



31. Without pursuing any further these conditions to an ex- 

 ternal change of place of the parts of a galvanic circuit, let us 

 now turn to those changes in the qualitative state of the circuit 

 which are produced by the electric current, i. e. in the internal 

 relation of the parts to each other, and which derive their ex- 

 planation from the electro-chemical theory of bodies. Accord- 

 ing to this theory, compound bodies must be considered as a 

 union of constituents which possess dissimilar electric states ; or, 

 in other words, dissimilar electroscopic force. But this electro- 

 scopic force, quiescent in the constituents of the bodies, differs 

 from that to which our attention has hitherto been directed, in- 

 asmuch as it is linked to the nature of the elements, and can- 

 not pass from one to the other, without the entire mode of ex- 

 istence of the parts of the body being destroyed. If we con- 

 fine ourselves, therefore, in the following considerations, to 

 the case where changes, it is true, occur in the quantitative re- 

 lation of the constituents, and where consequently chemical 

 changes of the body, composed of these constituents, also occur, 

 but where the constituents themselves undergo no alteration 

 destroying their nature, we are able to show the validity of all 

 the laws above developed of electric bodies with reference to 

 their reciprocal attraction and repulsion, only the transition of 

 the electricity from one particle to the other entirely disappears 

 in the consideration of chemically different constituents. A di- 

 stinction here exists with reference to electricity exactly similar 

 to that which we are accustomed to define relative to heat, by 

 calling it sometimes latent, sometimes free heat. For the sake 

 of brevity, we will in like manner term that electroscopic force 



