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, and n, may be determined by 
analysis. Provided, therefore, we can find the value of #, and «, 
the conductivity can be calculated. 
In a paper communicated to this society in 1896, Professor 
MacGregor* explained a method for the determination of the e's 
1 
in the above formula. He applied this method tosome 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 caleulated, 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. MeIntosh,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 puritication 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, rx (1896), p. 101. 
+ Transactions N. S. Inst. Science, rx (1896), p. 120. 
