Hackett and Fekly — The Polarisation of a Leclanche Cell. 281 



withdrawn. In addition the electrolysis which accompanies the discharge of 

 the ions involves changes in the electrolyte bathing the electrode. This, 

 in itself, may involve an alteration in the potential difference between the 

 electrode and the electrolyte. The difference of potential for a tenfold 

 change in concentration is of the order of 0"05 volt, and therefore can only 



5 6 



Time (minutes). 



Fig. 1. 



10 



account for a small fraction of the polarisation. This is the order of that 

 part of the polarisation which recovers slowly, suggesting some concentration 

 effect such as could only disappear by equalisation of the concentration 

 through diffusion, an essentially slow process. We shall, therefore, pro- 

 visionally ascribe this part of the polarisation to changes in concentration, 

 and term it the concentration-polarisation. We turn now to that part of the 



2 z2 



