182 MR J. Y. BUCHANAN ON THE 



MR = BeClj. MgClo. CaClg. 



- ^^,^,?i^.'^ - = 0-669 0-821 0-815 



1/16 MR 



^??^ ^^,~t!^ = 0-520 0-858 0-841 



1/128 MR 



From this table we see that the increment of specific gravity produced by dissolving 

 1/2 ME. in 1000 grams of water is exactly proportional to the molecular weight of the 

 salts in the case of MgClg and CaCla, and that this proportionality is maintained for 

 values of ??i=:l/16 and 1/128. In the case of BeClg, however, the proportionality 

 fails. 



It will he remarked that the specific gravities of the solutions of beryllium chloride 

 for which m = 1/512 and 1/1024 fall below unity, and the values are quite authentic. It 

 follows that the displacements of these two solutions must be greater than the sum of 

 the displacements of the salt and the water which they respectively contain. A 

 similar feature is observed in the saturated solutions of caesium salts, § 127, 

 Table III. 



Comparing the values of c?S for concentrations greater than 1/2 gram-molecule, they 

 diminish from 0'064018 for MgCL at TO gram-molecule concentration to 0'048345 at 

 4*0 gram-molecules, while in the case of CaCla the values are 0"075363 at I'O gram- 

 molecule, and 0'058415 at 4*0 gram-molecules concentration. 



The variation in the values of c?S for solutions of CaClg between m = 6*0 and 'm= 6'6 

 does not exhibit itself in a regular decrease but an oscillatory one, for the value at m = G'O 

 is 0-004541, rising to 0-004810 at w = 6-1, with a fall to 0-004471 at m = 6-2, rising 

 slightly again at m = 6'3 to 0-004506, then decreasing to 0-004325 at tn = 6-4 and to 

 0*004299 atrn = 6-5, the general tendency being to decrease in value with increasing 

 concentration. 



5 101. Values of -^ — and — . — -The features of the displacement of the solutions are 

 dm m 



best exhibited by discussing the values of -j— and — . The values of ,— are obtained 



dm m dm 



from columns 7 and 1. 



The solutions of the salts with concentrations less than 1 gram-molecule give values 



dA 

 for -^ — which are highest in the case of beryllium chloride, while those of magnesium 



Ctith 



chloride are lowest, those of calcium chloride being intermediate. 



o 



dA 

 The value of -^ — for beryllium chloride solution when m=l/2 is 28-66, and this 



decreases to 23-55 when m=l/32, rising to 26-58 at m= 1/128. There are two low 

 values, namely, 18-02 and 15-51 at m— 1/256 and 1/512 respectively, with a value of 

 27-85 at m= 1/1024. 



In the case of magnesium chloride the value of -j— at m = 1/2 is 2292, and the 

 value decreases with succeeding concentrations to the value 17-37 at m= 1/32, which 



