148 ON THE DEPRESSION OF THE FREEZING-POINT 



As a change in the atmospheric pressure would cause a corres- 

 ponding change in the thermometer, the freezing-point of the 

 water used was determined about every three hours. The 

 temperature of the room was kept as low and as constant as 

 possible during the experiments, and no observation was made 

 when it was above 5G. 



Since the freezing of my solutions, was started about 0.1 

 degree below the freezing-point, the amount of ice formed was so 

 small that the correction usually applied for the change in con- 

 centration, and, therefore, in the depression, comes within my 

 limit of error. Thus the results are recorded without any 

 correction. 



Simple Solutions. 



With the electrolytes K Cl, Na Cl, and H Cl, there is only 

 one possible way for their molecules to dissociate, namely, into 

 two ions. Hence expression (1) reduces to 



For the determination of the values of M, the other quanti- 

 ties, <?, n and a are obtained from observations on simple solu- 

 tions ; a being taken equal to the ratio of the specific molecular 

 conductivity to the specific molecular conductivity at infinite 

 dilution. As the solutions are at a temperature of about 0C. in 

 the determination of the freezing-point, the ionization coefficients 

 should be obtained at approximately the same temperature. 

 For this purpose measurements were made of the conductivity 

 at 0, both of solutions of the range of concentration used in the 

 observations of the freezing-point and also of very dilute 

 solutions of the electrolytes. These latter measurements are 

 required for the determination of the specific molecular con- 

 ductivities at infinite dilution for 0C. 



Determination of the Specific Molecular Conductivities at 



Infinite Dilution for 0C. 



A series of simple solutions varying in concentration from 

 01 to .0001 in the case of the salts, and from .01 to .001 for the 



