320 CONDUCTIVITY OF AQUEOUS SOLUTIONS. ARCHIBALD. 



dilute mixtures. But the fact that the differences are so large 

 where a double salt may exist, would seem to furnish evidence 

 for the assumption, that in the more concentrated solutions of 

 the double Sulphate of Potassium and Copper, the molecules of 

 the double salt are not all broken up, but exist to some extent 

 as a double salt in the solution. 



For solutions of the Copper-Potassium sulphate, more dilute 

 than 0.1 equivalent gramme-molecules per litre, as for the Zinc- 

 Copper and Sodium-Potassium sulphate mixtures, through as 

 wide a range of dilution as here examined, the differences are 

 within the limit of observational error and change sign fre- 

 quently, which seems to show that they are due to accidental 

 errors. It is thus possible to calculate the conductivity of these 

 solutions and mixtures ; and it would follow that, as far as the 

 conductivity measurements can show, for the more dilute solu- 

 tions of Copper-Potassium sulphate there is no double salt 

 existing as such in the solutions. 



