DEPRESSIONS FOR ELECTROLYTES MACGREGOR. 215 



current is to be regarded as being the same as when the current 

 is not flowing. But as it has been shown that electrically deter- 

 mined coefficients enable us to predict within the limit of error 

 of observation, not only the conductivity and the results of 

 electrolysis* of moderately dilute complex solutions, but also their 

 density, viscosity, and other non-electrical properties,^ 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 ionixation coefficients at 0, are 

 unfortunately few. Whethanrf has recently published some 

 most valuable determinations, having measured the conductivity 

 at 0, of series of solutions down to extreme dilution, with what 

 one may call appareil de luxe, and found the ratio of the equiv- 

 alent 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 acid is probably 

 lower than it would be, were it not for the disturbing influence 

 whatever it is, which makes the equivalent-conductivity-con- 

 centration curve not only reach, but pass through a maximum 

 point. 



Archibald and Barnes,:}: working in my laboratory- , measured 

 the conductivity at and 18 for series of solutions, down to 

 dilutions, at which the ratio of the two conductivities became 

 constant ; and assuming that the same ratio would hold at 

 extreme dilution, they calculated the equivalent conductivity at 

 extreme dilution for 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 



* MacGregor : Trans. Roy. Soc. Can. (2), 4, Sec. 3, 117, 1898. 



t MacGregor : Trans. N. S. Inst. Sci. 9. 219. 1895-7, and Phil. Mag. (5), 43, 46 and 

 99,1897. Also Archibald : Trans. N. S. Inst. Sci. 9, 335, 1897-8, and Barnes : Ibid., 10, 49. 

 and 113, 1899-1900. 



t Ztschr. f. phys. Chem., 33, 344, 1900. 



t Archibald : Trans. N. S. Inst. Sci., 10. 33, 1898-9. Barnes : Ibid., 10. 139, 1899- 

 1900, and Trans. Roy. Soc. Canada, (2), 6, , 1900. 



