44 



current had been interrupted ii gveal potential difference witli the auxili- 

 ary electrüde could still be demonsti-ated viz. an anodic polarisation 

 tension of 0,95 Volt, and a cathodic polarisation tension of 0,5 Volt. 

 These tensions decreased with diminishing velocity to 0, as a proof 

 that the metal assumes internal equilibrium by the aid of the 

 electrolyte. As on account of the oscillations of the mirror of the 

 galvanometer the said tensions could not be observed quickly enough 

 after the current had been interrupted, the above values give the tensions 

 some seconds after the interruption of tlie current. Immediately after 

 the interruption they will have been -j- 1,88 V resp. — 1,77 V. Hence 

 nickel, used as anode, becomes superficially a metal nobler than 

 platinum as we know it. 



Cadmiu7n. 



4. Cadinium is a metal lying between silver, copper, and lead 

 on one side and nickel on the other side with regard to the velocity 

 with which its internal equilibrium sets in. 



For this metal we found what follows : 



TABLE 5. 

 Cadmium electrode in 1/2 N. Cd (N03)2-solution. 



V-anode 



V-cathode 



Besides that the polarisation is smaller here than for nickel, it is 

 noteworthy that while for nickel the anodic and cathodic polarisa- 

 tion tension differ little, this difference becomes pretty considerable 

 for cadmium, at least for large current densities. This peculiarity 

 may be explained in a simple way by means of the A,A'-figure given 

 in the preceding communication. (See Fig. 3.^) 



Suppose that with unary electromotive equilibrium at the given 

 temperature the electrolyte L and the metal phase >S coexist, then the 



») Here the potential difieience of the metal with respect to the electrolyte has 

 been given. 



