4.JT' ft fi y^ 

 cf,(Aj/¥)= ~^j—.j{I-I^)dB (16) 



o 

 We must further take the changes of concentration in the different 

 elements of the electrolyte into account. If we introduce the concen- 

 tration c as the number of srammolecules of the dissolved substance 

 per unity of mass of the solution, this is modified by the passage of 

 the quantity of electricity e. If the density of the electrolyte is q, 

 then the variation of density, when the volume remains unchanged, 

 will amount to : 



ÖQ = dv . (17) 



in which rfr is given by (11) and (12). By means of this we find 

 easily for the change of concentration : 



1 — mc 

 dcr=(fv (18) 



771 . Q 



Now for dilute solutions very nearly : 



x^ = X.m.Q.c (19) 



holds, in which / is the so-called absolute specific susceptibility per 

 unity of volume, which is considered as independent of q ^). We 

 get from this by the aid of (17) and (18) : 



This then gives, as x^ must be considered as small : 

 B 



2jr B\/^.öv. 



(fjsp.d^:d = 



When we multiply this expression by the volume element (h, then 

 introduce the value of év from (11) and (12), and integrate with 

 respect to the whole volume of the solution, we get : 



V s 



If we assume 7i to be constant, which is permissible, on account 



of the relati\^e smallness of this term, if we suppose further that 



at the anode B = 0, at the cathode in air B =^ H, we get : 



2T7?i.y.e.« -— 

 ö,{LmW) = -^^.H\ (20) 



k.s 



1) Relation (19) liolds of course only as long as the specific magnetic properties 

 are independent of the concentration. 



50* 



