167 



in which the potential difTerence of the nickel electrode has become 

 equal to that of the hydrogen eleL'trode. This may be graphically 

 represented in the way as has been done in fig. 2. 



Zi=0 



In consequence of the disturbance point (/ has got in point d' , 

 and represents, therefore, the ennobled nickel phase which coexists 

 with c' and the hydrogen phase e' . 



It could be derived from our considerations how we have to 

 proceed when we want to know the potential of the unary nickel, 

 or in other words the equilibrium-potential. Tiien the nickel is to be 

 brought into a solution with a liydrogen-ion-concentration, smaller than 

 that in the electrolyte c. Then our A,A'-diagram 3 shows that under 

 these circumstances e.g. the electromotive equilibrium between the 

 nickel phase d" and the electrolyte t;" will be established, the potential 

 difference of which practically coincides with that of the unary 

 metal, which is perfectly free from hydrogen and indicated by a. 



It is necessary to point out that when a metal is in electromotive 

 equilibrium with a coexisting electrolyte, the electron-concentration 



