( 432 ) 

 and it would be a sheer accident if we also had: 



Thoio exists therefore as a rule no equilibrium of partition 

 between tlie Ions in the two solvents. For example there may be 

 in the second solvent relatively too few K-Ions, too many Cl-Ions. 

 Since a system out of erpiilibrium tends to pass into a condition of 

 equilibi-ium, K-Ions from Ai will migrate to A,, and remain there 

 in the boundary-layer, while the corresponding liberated Cl-Ions 

 remain in the boundary -layer of Aj (inversely Cl-lons will migrate 

 from A.^ to Aj, whilst the corresponding lil)erated K-lons remain in 

 A,. Both add themselves to the above mentioned similar ions in the 

 boundary-layer). The consequence is the occurrence of an electrical 

 cloublelayer and liierefore of a potential-difference. And it is this 

 potential-difference, which will restore the originally non-existing 

 equilibrium between the Ions. 



All this may be put into a very simple mathematical form. 



Let V^ be the electrical potential of Aj, I"^ that of A,, so that 

 Z- = Fj — V^ represents the potential-difference at the boundary (in 

 the case we are dealing with, L is therefore jfositice), then the 

 formula for the equilibrium of the K-lons will be: 



^A.-fV-. 



de -\- Lde= 0, 



s 



which is at once obvious, when we consider tlie virtual passage 

 from the left to the right over the boundary of siicii a quantity of 

 K-lons, that the quantity of electricity transported is de. As the 

 quantities /i relate to eqnivalent-iiwixni'ü'xQS, and as these do not cor- 

 respond with one electric unit, but with e (= 9653(3) electric units, 

 «,, — fi must be divided bv f. 



Aa Ai 



For the equilibrium of the Cl-Ions we find in tlie same manner: 



-^ ^ - L de = 0. 



s 



The sign at L is now negative, because on account of the negative 



charge the change in the electrical energy is — Z- de. 



We therefore obtain from the two relations, after dividing by de: 



K Ag At ' 'a ' '1 /• <x 



That these two equations for A are not conflicting, is at once 

 apparent. For the relation, resulting therefrom 



leads at once to (3). 



