[BARNES] DEPRESSION OF THE FREEZING-POINT 45 
It may be well to note that if we apply the theoretical equation : 

(5) 
a 
À 
taking c, the specific heat of the solution, to be equal to 1, and À, the heat of 
solidification of unit weight of the solvent, to be equal to 80, 6, the 
over-cooling, being in my observations equal to 0‘1 centigrade degree, 
y the fraction of the solution which solidifies is 54, or the solution 
becomes more concentrated by about 0°12 per cent. That is, the 
freezing-point depressions are about 0°12 per cent too great. It appears 
that this correction is smaller than that deduced from Raoult’s method. 
Loomis' found by another method that the correction, when the over- 
cooling was about 0:15 degree, was 0°3 per cent, while that obtained under 
the same circumstances by equation (5) was about 0°2 per cent, which is 
also considerably smaller than that obtained by the experimental method. 
DETERMINATION OF THE IONIZATION COEFFICIENTS AT 0°C. FOR SIMPLE 
SoLUTIONS. 
The ionization coefficients employed in expression (1) were de- 
termined by the conductivity method and were taken to be equal to the 
ratio of the specific molecular conductivity to the specific molecular 
conductivity at infinite dilution. As the solutions were at a temperature 
of about 0°C. in the freezing-point measurements, the ionization coefficients 
should be obtained at approximately the same temperature. For this 
purpose observations were made on the conductivity at 0° of simple solu- 
tions of the range of concentration used in the freezing-point measure- 
ments and also of very dilute solutions of the acids. These latter obser- 
vations were required for the determination of the specific molecular con- 
ductivity at infinite dilution for 0° C. 
A series of simple solutions of the two acids varying in concentrauon 
from 6-01 to 0:001 were prepared and their conductivities measured at 
18° and at 0°. The conductivity of the water used in the preparation of 
these solutions was measured at both temperatures and its value 
subtracted in each case from the conductivity of the solution. Con- 
siderable care was required with these dilute solutions to obtain good 
results. he solutions and the water used were exposed as little as 
possible to the air and the measurements were taken immediately after a 
solution was made. The electrodes were thoroughly washed with a 
portion of the solution before placing them in the cell. The observations 
were repeated many times and the mean of the values obtained was 


1 Phys. Review, 1, 283, 1894. 
