III. ON THE CALCULATION OF THE CONDUCTIVITY OF AQUEOUS 

 SOLUTIONS CONTAINING THE DOUBLE SULPHATE OF 

 COPPER AND POTASSIUM, AND OF MIXTURES OF EQUI- 

 MOLECULAR SOLUTIONS OF ZlNC AND COPPER SUL- 

 PHATES. BY E. H. ARCHIBALD, B. So., Dalhousie 

 College, Halifax, N. S. 



(Communicated by Prof. J. G. MacGregor, 21st February, 1898.) 



In a paper,* read before this Society last October, I showed 

 that for mixtures of solutions of Potassium and Sodium Sulphate, 

 when not more concentrated than one equivalent gramme- 

 molecule per litre, it was possible, by the aid of the dissociation 

 theory of electrolysis, and by employing Prof. MacGregor's 

 graphical methodf for the determination of the. ionization 

 coefficients in the mixture, to calculate the conductivity within 

 or but little beyond the limits of an error of obsesvation. The 

 conductivity of mixtures of solutions of Potassium and Sodium 

 Chloride, which were measured by Bender, have been calculated 

 by Prof. MacGregor, *f who found that for mixtures of these 

 solutions, more dilute than two equivalent gramme-molecules 

 per litre, it was possible to caclulate their conductivity within 

 the limits of experimental error. D. Mclntosh J has measured 

 and calculated the conductivity of mixtures of solutions of 

 Potassium and Hydrogen Chloride, and found the conductivity 

 calculable within the limits of experimental error, up to a mean 

 concentration of one equivalent gramme-molecule per litre. 



At Prof. MacGregor's suggestion I have made the observa- 

 tions described in this paper, to find if the conductivity is also 

 calculable in the case of a solution containing a double salt, on 

 the assumption that the salt does not exist as a double salt in 

 the solution. The salt selected was the double Sulphate of 

 Copper and Potassium. 



* Transactions N. S. Inst. Science, IX. (1897), p. 291. 

 t Transactions N. S. lust. Science, IX. (1896), p. 101. 

 t Transactions N. S. Inst. Science. IX. (1896), p. 122. 



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