292 ON THE CALCULATION OF THE CONDUCTIVITY OF 



the same values in the mixture as in the simple solutions, may 

 be determined by conductivity measurements, to great dilution,. 

 of each electrolyte; and n l and 7? 2 may be determined by 

 analysis. Provided, therefore, we can find the value of a l and 2 

 the conductivity can be calculated. 



In a paper communicated to this society in 1896, Professor 

 MacGregor* explained a method for the determination of the as 

 in the above formula. He applied this method to some mixtures 

 of solutions of Sodium and Potassium Chloride, examined by 

 Bender, and found it possible to calculate their conductivity 

 when they contained less than two gramme-molecules per 

 litre, within the limits of experimental error. For more concen- 

 trated mixtures he found the observed values to be greater than 

 the calculated, and the difference to increase with the concentra- 

 tion, till at a concentration of four gramme-molecules per litre 

 the difference was between 3 and 4 per cent. The conductivi- 

 ties of mixtures of Sodium and Hydrogen Chloride solutions were 

 measured and calculated by D. Mclntosh,f who found that the 

 conductivity of these mixtures could be calculated, within the 

 limits of experimental error, up to a mean concentration of 

 about one gramme-molecule per litre, and that for a mean con- 

 centration greater than this, the calculated value was greater 

 than the observed. 



The measurements, described below, were undertaken with the 

 view of ascertaining if the conductivity was calculable, in the 

 case of mixtures of solutions of Potassium and Sodium Sulphates, 

 salts of more complex molecular structure than those previously 

 examined. They were conducted in the Physical and Chemical 

 Laboratories of Dalhousie College. 



The work included purification of the salts, and of water; 

 preparation and analysis of a series of simple solutions, and 

 determination of their conductivity ; plotting curves, giving the 

 relation of concentration of ions to dilution for these simple 

 solutions ; preparation of the mixtures, and measuring and 

 calculating their conductivity. 



* Transactions N. S. Inst. Science, ix (1896), p. 101. 

 t Transactions N. S. Inst. Science, ix (1896), p. 120. 



