KAHLENBERG — THEORY OF ELECTROLYTIC DISSOCIATION. 311 



resented in the figures. A comparison of Tigs. 1 and 2 shows 

 that at 95° the MgS0 4 curve is practically a straight line, and 

 that the curves of NaCl, BaCl 2 , and AgN0 3 also exhibit a 

 marked tendency to straighten out at the higher temperature. 

 It should be stated in this connection that the curve for CdS0 4 1 

 preserves more of its convexity toward the axis of abscissas at 

 95° than do the curves for the other sulphates. Curves that 

 were charted from data obtained for the same salts at 18° and 

 at 25° showed a marked similarity 2 to those in Fig. 1 (at 0°) 

 and indicate that the change in the shape of the curves at 0° and 

 at 95° takes place gradually as the temperature rises. It 

 should be clearly borne in mind that the curves for even very 

 closely analogous salts are not perfectly parallel; all that can 

 be said of them is that they are similar in trend. . 



The results of the freezing-point determinations are given in 

 Tables 3 to 11. The headings of the tables are self-explanatory. 

 In calculating the molecular weights 18°. 9 was assumed as the 

 lowering of the freezing-point caused by the presence of one 

 gram-molecule in 100 grams of water. 



Table 3. 3 



Sodium Chloride (NaCl) Mol. Wt. 58.5. 



^bis curve is not represented in the figures. The curve for HgCl Q — also not 

 represented— is practically a straight line at 95°. 



2 Such similarity has also been pointed out at various times by other observers. 



3 The four determinations marked * in this table were made in this laboratory 

 by Mr. G. M. Wilcox. The other two determinations were made by the writer. 



* In this table, and also in the succeeding tables (4 to 31), the computation 

 of the amount of solute contained in 100 grams of water has been carried ont 

 to more decimal places than is necessary. Through an inadvertence these num- 

 bers were not rounded off to fewer decimal places, as they should have been, 

 especially in the case of the more concentrated solutions. 



