OH 



and /v^j/, indicalc llie .sadinilioii coiiccjilratioiis of the iiietal-ioiis 

 M" anc( Af^-'-'-'}, that 



1 1 



c 



and as in the case supposed here 



V3I., = 2VM (4) 



we get : 



K\yi- - = Ku,-^ (5) 



4. The A, ,1' figure!, drawn here, holds for the case that tiie two 

 kinds of molecules and the two kinds of ions cannot be converted 

 into each other. If, however, an internal equilibrium is established, 

 only electromotive equilibrium is possible, when the coexisting phases 

 are both in internal equilibrium. This is immediately seen in the 

 following way. Equation 1 runs 



+ + 



Now 



SO that 



+ + 



or 



+ + 

 2nM — [iM^ =z 2/xji — n^J.^ ...... (6) 



from which follows that when in case of electromotive equilibrium 

 internal equilibrium prevails in the electrolyte between the metal- 

 ions, for which : 



+ + 



a consequence of this is that : 



2fij/ = fxj/j, 

 or in words that internal equilibrium must then also prevail in the 

 metal, and vice versa. As is directly to be seen, the same conclusion 

 follows from equation y5),. when we assume the validity of the law 

 of the chemical mass-action also in this case. As said before the 

 A,A'-tigure holds for a definite T, P and total metal-ion concentration. 

 The internal equilibrium in the metal phase is perfectly defined 

 for definite T and P. The internal metal-ion equilibrium in the 



1) These Proc. May D 190(5. IX p. 2. 



