378 Dr. R. A. Lehfeldt on Electromotive 



where E — electromotive force, 

 K = gas constant, 

 T = absolute temperature, 

 a = transference ratio for the cation, 

 n = number of ions formed from molecule of electrolyte, 

 r = least common multiple of the valency of the ions, 

 e = quantity of electricity associated with 1 gram- 

 equivalent of an ion, 

 d C 2 = concentration of the weaker and stronger solutions 

 respectively, 

 the electrode in the weaker solution being the anode. 



Now let us take a step nearer to the actual circumstances, 

 and consider the same cell with the electrolyte dissociated 

 incompletely, viz. to an extent 7! in the anode vessel, y 2 hi 

 the cathode vessel. 



We may carry out a cyclic process at constant temperature 

 as follows : — 



(1) Let a quantity SH of electricity flow through the cell from 



anode to cathode. Then — equivalents of metal dissolve at 



the anode, the same mass is deposited on the cathode, and at the 



boundary between the two solutions # — equivalents of metal 



(1— #)8H 

 are transferred with the current of acid radical in 



the opposite direction. 



(1 — .t) 8 H 

 The anode vessel therefore gains equivalents of 



each ion or — mols. Now it will somewhat simplify 



re 

 the explanation, without any loss of generality, if we assume 

 that the anode and cathode vessels each contain unit volume 

 (1 c.c.) of solution. Then the anode vessel contains C ± mols. 

 of salt, and the change in that quantity is 



Similarly, 



re 



re 



The work done by the cell in this process is 



Ere 

 1 — x 



(2) Place the anode solution in a cylinder closed by a 



