48 IONIZATION COEFFICIENTS.—ARCHIBALD. 
If we compare the percentage differences of the above table 
with the corresponding differences in the case of the constituent 
simple solutions (Table IV, p. 45), it will be seen that the former 
are in general equal to the arithmetic means of the latter. Hence 
the depressions of the freezing-point of the mixtures have been 
calculated with the same degree of accuracy as those of the 
simple solutions. 
The test which has thus been applied to Prof. MacGregor’s 
method of determining the ionization coetlicients in a solution 
containing two electrolytes with a common ion, and which the 
method has completely satisfied, is, however, not a severe one. 
It was intended, after the experiments on equimolecular solu- 
tions, to take up mixtures of solutions of different concentra- 
tion with respect to the two electrolytes. Unfortunately I was 
prevented from doing so by lack of time. 
In conclusion, I wish to express my thanks to Prof. 
MacGregor for valuable suggestions kindly given. 
