Freezing-point Depressions for Electrolytes. 509 



the conductivity and results of electrolysis* of moderately 

 dilute complex solutions, but also their density, viscosity, and 

 other non-electrical properties f, it would appear to be 

 probable that for moderately dilute and very dilute solutions 

 electrically determined coefficients are approximately exact, 

 not only for a solution through which a current is passing, 

 but generally. 



The available data as to ionization-coefficients at 0° are 

 unfortunately few. Whetham % has recently published some 

 most valuable determinations, having measured the conduc- 

 tivity at 0° of series of solutions down to extreme dilution, 

 with what one may call appareil de luxe, and found the ratio 

 of the equivalent conductivity to the maximum equivalent 

 conductivity. For neutral salts his coefficients must inspire 

 great confidence. But in the case of the acids they seem to 

 me to be probably too high. For the maximum equivalent 

 conductivity of an a.cid is probably lower than it would be, 

 were it not for the disturbing influence, whatever it is, which 

 makes the equivalent-conductivity-concentration curve not 

 only reach but pass through a maximum point, as concen- 

 tration diminishes. 



Archibald and Barnes § , working in my laboratory, 

 measured the conductivity both at 0° and 18° for series of 

 solutions down to dilutions at which the ratio of the two con- 

 ductivities became constant ; and assuming that the same ratio 

 would hold at extreme dilution, they calculated the equivalent 

 conductivity at extreme dilution for 0°from Kohlrausch's values 

 for 18°. They used this method only because appliances were 

 not available with which observations at extreme dilution 

 could be made. If the ratio mentioned really does become 

 constant as dilution increases, the method is likely to give 

 coefficients with too low or too high values according as the 

 ratio at moderate dilutions diminishes or increases with 

 dilution (it was found to increase with KC1 and K 2 S0 4 ). For 

 it will probably become constant within the limit of error of 

 observation before it has really reached constancy. And if 

 it changes with dilution in a slightly wavy manner, even 

 though on the whole tending to constancy, it may be regarded 

 as having become constant when really passing through a 

 maximum or minimum point. 



* Trans. Roy. Soc. Can. (2) iv. sec. 3, p. 117 (1898). 



f See Phil. Mag. [5] xliii. pp. 46 & 99 (1897) ; also Archibald, Trans. 

 Nova Scot. Inst. Sci. ix. p. 335 (1897-98) ; and Barnes, ibid. x. pp. 49 & 

 113 (1899-1900). 



X Zschr.f. phys. Chem. xxxiii. p. 344 (1900). 



§ Archibald, Trans. N. S. Inst. Sci. x. p. 33 (1898-9) ; Barnes, ibid. x.. 

 p. 139 (1899-1900) ; and Trans. Rov. Soc. Can. [2] vi. (1900). 



Phil. Mag. S. 5. Vol. 50. No. 306. Nov. 1900. 2 N 



