By experiments on diffusion this constant has been found by Scheffer, and the numbers observed agree with those calculated (HC1= 2.30, HNO 3 = 2 22, NaCI = I II).
The following, though volatile at higher temperatures, are not volatilized at dull redness: KC1, NaCI, LiC1, NiC1 2, CoC1 2, MnC1 2, ZnCl 2, MgCl 2, PbCl 2, AgCI, the chlorides of potassium, sodium, lithium, nickel, cobalt, manganese, zinc, magnesium, lead, silver.
It appears that the relatively enormous deviations of CaC1 2 from Raoult's law are accounted for on the hypothesis that a=9, but there is a slight uncertainty about the degree of ionization of the strongest solutions at-50° C. Cane-sugar appears to require 5 molecules of water of hydration both at o° C. and at loo° C., whereas KC1 and NaCI take more water at loo° C. than at o° C. The cases considered by Callendar (loc. cit.) are necessarily limited, because the requisite data for strong solutions are comparatively scarce.