THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



STfTA R y u 



[FIFTH SERIES.] 



Eu. r ' 



DECEMBER 1898.V ^47^-r Q? * 



LV. On </*£ Conductivity-Method of Studying Moderately 

 Dilute Aqueous Solutions of Double Salts. By J. G-. 

 MacG-regor and E. H. Archibald, Dalhousie College. 

 Halifax, N.S. * 



THE conductivity method of determining whether or not 

 double salts exist as such in solutions consists in a com- 

 parison of their observed conductivity with what it is 

 supposed their conductivity would be if the constituent salts 

 were entirely uncombined. The difficulty which has always 

 presented itself has been to determine what the conductivity 

 would be on this assumption. 



The difficulty vanishes in the case of extremely dilute 

 solutions, because in their case it follows from the principle, 

 of the superposition of small effects alone, that, if no double 

 salt exist as such in solution, the specific conductivity will be 

 equal to the volume mean (or the arithmetic mean) of the 

 conductivities of the simple solutions of the constituent salts 

 by the mixture of which in any given ratio as to volume (or 

 in equal volumes, as the case may be) the given solution 

 would be produced (we may for shortness call this volume 

 mean, the volume mean conductivity of the solution, and the 

 simple solutions the mixing of which would produce the given 

 solution, its mixture constituents). Accordingly Grrotrianf, 

 Bouty J, Wershoven§, Kistiakowsky ||, and Jones and 



* Communicated by the Authors. 

 t Wied. Ann. xviii. p. 177 (1883). 

 t Ann. Chim. Phys. [6] iii. p. 433 (1884). 

 § Ztschr. phys. Chem. v. p. 481 (1890). 

 || Ibid. vi. p. 97 (1890). 

 Phil. Mag. S. 5. Vol. 46. No. 283. Dec. 1898. 2 N 



