Theory of Electrocapillarity. 379 



branches of two solutions, whose concentrations are Cj and c 2 , 

 (t = 15°) for a monovalent cation and 



is 0*057 log 10 



,— for a bivalent one. 



0-029 log] 



If we take account of the 



incomplete dissociation, we must replace c by ac, where 

 a is the degree of dissociation. In Table I. are given the 

 values of fa — tyi which correspond to different values of 

 7 (the maximum surface-tension between mercury and water 

 is assumed to be 100). The measurements were carried out 

 with a capillary electrometer as described by Gouy *, the 

 large mercury electrode being always immersed in a n/10 

 solution of KC1. 



Let us now denote by t|t the potential difference between 

 the mercury in the decinormal calomel electrode and the 

 mercury in the capillary tube, by i the value of the current 

 which passes through the capillary electrometer, and by w 

 its internal resistance. Then, obviously ty = applied E.M.F. 

 — nc. The value of w was calculated, that of i determined 



Fig. 2. 

 ioo r 



60 



with an Edelmann string galvanometer. The term hv could 

 be neglected at higher concentrations, but with ??./1000 

 solutions it amounted to 0*01 volt and more. The electro- 

 capillary curves of KX0 3 are plotted on fig. 2. 

 * Ann. chim. phys. (7) xxix. p. 178 (1903). 



9 p 9 



