AQUEOUS SOLUTIONS. McKAY. 



355 



most of the signs being negative. The results of these measure- 

 ments seem to show that at such dilution the double salt is 

 separated into its components. 



The conductivities of the strong double salt solutions seem 

 to he greater than the conductivities of corresponding mixtures, 

 though in the case of dilute solutions they agree. 



A fact which makes the writer somewhat suspicious of the 

 trustworthiness of the measurements of the mixtures of strong 

 solutions is that the density of these mixtures was found to be 

 less than the mean density of the constituent solutions, amount- 

 ing at the concentration 0.8 to a difference of 0.1 per cent. 

 The error of a density measurement might be 0.03 per cent. The 

 density of the double salt solutions was found to be equal to the 

 mean density of the K 2 S0 4 and MgS0 4 solutions of the same 

 strength. The following are the measurements on which these 

 statements are based. With the exception of those for the 

 MgSO 4 solutions, the values of which are taken from Kohlrausch 

 and Hallwachs' determinations, they were made by the writer. 



The results of the double salt measurements lead the writer 

 to conclude that in dilute solutions the double salt entirely 

 separates, but that in strong solutions the two component salts 

 are at least partly united. 



