Volumes of Salt- Solutions. 

 Table I. 



181 



M. 



MI. 



MBr. 



MCI. 



(I-Br)M. 



(Br-Cl)M. 



Li 



36-6 



279 



19-2 



8-7 



8-7 



K 



45-4 



36-3 



27-4 



9-1 



8-9 



Na 





256 



17-4 





8-2 



Ca 



54-2 



37-7 



20-2 



8-5 



8-7 



Sr 



57-7 



401 



23-5 



8-8 



83 



The agreement is not very good, and in many cases the 

 molecular volumes differ considerably from those given by me 

 in a subsequent part of this paper ; still they point to an 

 agreement, which is not complete for the reasons given 

 above. 



After I commenced this subject, I was much struck by the 

 fact that water of crystallization has no effect on the molecular 

 volume of a salt in solution. The case in which I first noticed 

 it was that of sodium sulphate, which crystallizes with ten 

 molecules of water. 



Now, if we determine the molecular volume of a solution 

 which contains two molecules of sodium chloride (an anhydrous 

 salt in the solid state) in the 100 molecules of water, and the 

 molecular volume of a solution containing one molecule 

 (2 equivalents) of sodium sulphate, we find the following : — 



Mol. vol. Na 2 Cl 2 100 H 2 = 1836-3 



„ „ JSTa 2 S0 4 100 H 2 = 1819-3 



(C1 2 -S0 4 ), then, = 17-0 



and therefore the change in molecular volume produced by 



SO 

 the replacement of CI by -^ in combination with sodium, 



i. e. 



Na(ci--^ 4 ) = 8-5 = A; 



for a solution of half the strength, 



WC1~^ = 9-2 = A. 



