THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[FIFTH SERIES.] 



JULY 1891. 



I. Some Points in Electrolysis. By J. Swinburne*. 



LET a cell be considered, with its external circuit closed 

 through, a resistance so high that in comparison the 

 internal resistance is negligible. The cell discharges, and 

 in passing from one pole to the other each coulomb does a 

 certain quantity of work proportional to the difference of 

 potential of the poles, E. This is really a mere definition : if 

 difference of electric potential between two points is defined 

 as what is measured by the work done on unit quantity of 

 electricity passing from one to the other, the work done is 

 numerically equal to E. The work done on the coulomb 

 passing onward through the cell to regain its original position 

 is equal to the work done when it passes through the 4 external 

 resistance. This work done on the coulomb may be supplied 

 at the expense of chemical energy, or there may be local 

 cooling somewhere. There may be chemical energy supplied 

 at some points, and absorbed at others, and heat may disappear 

 at some points, and may be evolved at others, but the 

 algebraical sum comes out equal to E. Call the poles of 

 the cell p and n, the positive pole being, for example, pla- 

 tinum and the negative such a metal as zinc, and suppose the 

 electrolyte to be one homogeneous fluid. Part of the work 

 done on the coulomb in passing from n to the electrolyte may 

 be supplied chemically and may be called E MC , another part 

 may be supplied by local cooling E nh1 c standing for chemical 



* Communicated by the Physical Society: read March 20, 1891 , 

 Phil Mag. S. 5. Vol. 32. No. 194.' July 1891. B 



