142 ON THE DEPRESSION OF THE FREEZING-POINT 
determination of the ionization coefficients of the electrolytes in 
the mixtures ;—calculation of the depression of the freezing- 
point in the mixtures, 
The experiments were carried out during the session of 
1899-1900 in Dalhousie College, Halifax. 
Materials, Apparatus and Methods. 
The salts and acids were obtained from Merck. The salts. 
were recrystallized once, and it was found that solutions of 
them, and also of the acid, had conductivity values showing 
satisfactory agreement with the values as given by * Kohlrausch. 
These electrolytes were therefore considered sufficiently pure 
for the purpose. The water used in making the solutions was 
purified by the method described in my former * paper, and it 
had a conductivity at 18°C. of about 0.95x10-° expressed in 
terms of Kohlrausch’s new ? unit (ohm™? em."?). 
The solutions of potassium and sodium chloride were 
prepared by direct weighing; the salts being first dried to 
constant weight in an air-bath. The hydrochloric acid solutions, 
were analysed volumetrically by means of a standardized sclu- 
tion of potassium hydroxide with phenol-phthalein as indicator. 
All burettes and pipettes used in the preparation and analysis. 
of these solutions were calibrated by the weight of distilled 
water they delivered, and the flasks by the weight of water they 
held at 0°C. 
Observations were made on the specific gravity at 18°C. of 
the simple solutions and their mixtures with a pycnometer of 
the Ostwald-Sprengel form. These observatious were made to 
obtain the knowledge whether or not there was any change of 
volume on mixing the simple solutions. It was found that with 
solutions of the concentrations used, there was no appreciable. 
change, and it was assumed that such would also be the case. 
at 0°. 
1 Kohlrausch u. Holborn: Leitvermégen der Elektrolyte, 1898, pp. 159, 160, tab. 2. 
2 Trans. N.S. Inst. Sci., 10, 49, 1898-99. 
3 Kohl. u. Holb., loc. cit., p. 1. 
