WILLIAM D. HARKINS 



153 



librium. However, the method of treatment for a simple case is presented below, 

 where the initial and equilibrium conditions are represented. 



Initial 



Here A' represents the number of mols of NaCI transferred from left to right. If X 

 happens to be negative, the equations will reveal that this is the case. 



The membrane product relation, written in the inexact form in which the con- 

 centration (C) is substituted for the activity, is 



{2C-X){C-X) = {C+Xy-, 

 or 



20-2,CX+X' = 0^-2CX+X' , 

 so 



X = iC . 



(xiC-x) (C-x) = {C+xy, 

 iiO-i2Cx+x^ = 0-\-2Cx-irx\ 



Na+ 



ci- 



}C 



Equilibrium 



R- 



loC 



Na+ 



Cl- 



ifC 



MEMBRANE "POTENTIAL" 



The equations for calculating the electromotive force for a liquid-liquid junction 

 are well known in the case in which different concentrations of the same salt are pres- 



