564 



This throins, Indeed, a peculiar light on the Volta-e^ect, for it 

 noio appears clearly that lohen realhj the Yolta-efject for metals in 

 the state of internal equilibrium should be zero or very small, which 

 comes to the same thing as equality or nearly equality of the mole- 

 cular thermodyuamic potential of the electrons in those metals, this 

 would be a special characteristic property according to the theory oj 

 electrons for metals in the state of internal equilibrium. 



But apart from the value of the Volta.-effeet, in the logical develop- 

 ment of the given theory of the electromotive equilibrium, the 

 Volta-effect cannot be neglected. ^) 



'; In this we will also point out that when the new views about the role of 

 the electrons and the electiomotive equilibiium are consistently applied to an 

 arbitrary electrical circuit, we arrive at the result that everywhere where a potential 

 difference occurs, a reaction takes place on passage of the current, in which the 

 change in free energy of the reaction proceeding at that place, determines the 

 value of the potential ditference. It is known that according to the given theory 

 at the places of contact metal-electrolyte this reaction consists: 1. of the splitting 

 up of metal ions into ions and electrons; resp. of the formation of metal atoms 

 from the electrically charged dissociation products mentioned here and 2 of the 

 transition of ions and electrons from the metal phase into the electrolyte or vice 

 versa. In this transition from one phase into the other the ions take a prepon- 

 derant part. 



When we consider the contact metal-metal, the just-mentioned transition consists 

 to by far the greater pari of the displacement of electrons from the metal M\ 

 to the metal Mo- 



This view ditfers accordingly from that which is particularly met with in German 

 handbooks, in which the opinion is embraced that the reactions during passage 

 of the current exclusively take place at the places of contact metal-electrolyte. 



It is clear that on application of the relation : 



dA 



E=A-T— 



dT 



to the transition of electricity from one metal into the other we may only conclude to: 



dA 



dT 



when in the process mentioned here no change of the thermo-dynamic energy 



takes place {E = 0). 



Leblanc does so in his handbook p. 227 (1914). and thus comes to the con- 



dA . 

 elusion that the Volta-effect must be small, because -j^, is small. 



According to the theory of electrons the difference in solubility heat of the 

 electrons in the two metals will, however, have to be taken into account. In the 

 isotherm transition of electricity between the two metals the free energy of the 

 electrons will change, and be converted into electrical energy in case of a reversible 

 process, the occurring change of the bound energy becoming manifest through 

 the latent heat, which heat is the heat of Peltier. 



dA 



It is this quantity, the heat of Peltier which, is represented byT— , , and not 



the Volta-effect. 



