Theory of Eledrocapillaritij. 377 



immersed in a solution of NaCl. The electrodes are con- 

 nected with the mercury by means of two condensers. The 

 potential differences between the solution and the Hg, Na, 

 and CI electrodes are respectively yfr, yjr^ yjr 2 . The quantity 

 of electricity which has passed through the solution since a 

 certain moment from 1 to 2 is E lf and from 1' to 2' E 2 . 

 The concentration of the NaCl, which we shall assume to be 

 completely dissociated, is c and the surface area of the 

 mercury s. The state of the solution is wholly determined 

 by the values of -v/r, c, and s. If we increase s by ds, keeping 

 ty and c constant, and c by dc keeping ty and s constant, 

 the work performed will be 



dA= [ 7 + (^_ tl ) S |- 1 +(t-* 2 )^] ds 



whence, as yfr^ and yfr 2 are functions of c and yjr, but not of s, 

 ~dc "dc "ds "dc "ds ' ^ ' 



where a*,_a+._rcr ,,. 



~W ~Ti ~^F { ' 



When a quantity of electricity equal to -^ — ds passes 



1 BE 

 from 1 to 2, ^ ^^ds gram-equivalents Na enter the solution 



and as many gr. eq. Hg are removed from it ; likewise, 



riE 

 when a quantity of electricity equal to -~-^ds passes from 



1' to 2', ^ ~^~^ s g r - ec ]» Hg and as many gr. eq. CI are 



removed from the solution. On the other hand, when the 

 surface is increased by ds, E x and E 2 being constant, T Ng ds, 



r cl <r/s, and yds gr. eq. Na, CI, and Hg respectively, are 



removed from the solution ; in consequence, as -v^ and c must 

 remain constant during the increase of s, 



1BE, IBB, ] 



1 *>~Y ^ ' ici_ F'B7' I ,„ 



e _ 1 /3E, , BE 2 \ _ j ' 



PAtf. 3%. S. 6. Vol. 40. No. 237. Sept. 1920. 2 C 



