396 



electrons would, therefore, have to be withdrawn from the metal 

 equilibrium, here therefore from the nickel equilibrium, which would 

 cause this equilibrium to be disturbed. If nickel behaved normalfj, 

 this disturbance would be immediately negatived, and it is easy to 

 see in what way this disturbance \yould be annulled. 

 This cannot take place through the reaction : 



for, the concentration {Nil) being very small, this is a reaction 

 that can produce but exceedingly few lYz-ions and electrons per 

 second. What would have to happen is this: the electrons and 

 nickel ions would have to go into solution from the metal and in 

 the metal- the reaction 



would have to take place. 



In this case the potential difference during the hydrogen generation 

 would be exclusively determined by the i\7-ion concentration 

 prevailing at the moment. 



The metal nickel however, behaves quite differently. 



As was already observed, nickel is exceedingly inert, i.e. its 

 internal equilibrium is very slowly established, and to this comes 

 that the hydrogen, which dissolves in the nickel to a small degree, 

 greatly retards the setting in of internal equilibrium. 



Now we may imagine the phenomenon to be like this : when 

 electrons have been withdrawn from the solution by the reaction : 



and in consequence of this ions and electrons have gone into 

 solution from the metal the disturbance of the internal equilibrium 

 is not abolished any longer, and the potential difference zVz-eiectro- 

 lyte has consequently become less negative. 



For nickel, which is so exceedingly inert under the influence of 

 the dissolved negative catalyst, hydrogen, the supposition suggests 

 itself that this process can continue till the electron concentration 

 of the nickel equilibrium in the electrolyte has become equal to 

 that of the hydrogen equilibrium. 



It is self-evident that it is supposed here that the electrolyte is 

 perfectly free from oxygen and that the result in question is to be 

 expected when we work e.g. in vacuum or in a hydrogen 

 atmoshere. We shall now examine what the potential difference 

 nickel-electrolyte has become in this case. 



For this purpose we return to the derivation of the equation of 

 electrons for the potential difference. The condition of equilibrium 



