22 



WORK OP CM. STINE. 



same amount of potassium chloride is added to the succeeding mixtures, the calcium 

 chloride can increase its water of hydration only slightly, and by a constant differ- 

 ence, with increase in the concentration of the calcium chloride added. Conse- 

 quently, there is increasing deviation, in fig. 1, between the curve representing the 

 value of M for the single solution and that representing M for the mixture. In 

 fig. 2 the difference between the values of M for calcium chloride in the separate 

 solution and in the mixture is approximately proportional to the difference in the 

 amount of water present acting as solvent towards the calcium chloride in the sepa- 

 rate solution and in the mixture. This is shown by curve II. 



It must be borne in mind that these results are based on the assumption that 



++ - - 

 calcium chloride breaks down at once into Ca, CI, CI ; also, that the entire decrease 



in conductivity upon mixing is due to re-formation of the molecules, whereas a part 



of the decrease is certainly due to viscosity and friction of the ionic spheres, as 



already mentioned. 



In order to ascertain the effect upon the hydrates formed, a pair of salts, both of which 

 have hydrating power, was next studied. 



For this purpose it was considered desirable to investigate, first, a case where 

 both the salts employed have a large hydrating power, and where the hydrating 

 power of the two salts in single solution is of the same order of magnitude. Calcium 

 chloride and magnesium chloride fulfill these conditions. (Tables 9 to 11.) 



Table 9. Calcium Chloride Data for Freezing-point and Conductivity Measurements, Weight- 

 normal Corrections, and Hydrates . 



