MIXTURES OF ELECTROLYTES MACGREGOR. 113 



will have a double effect on the calculated conductivity, (1) 

 affecting the value of a as determined from the curves, and (2) 

 introducing the factor p in the final computation. In the case 

 of Bender's solutions, though in some cases they were nearly or 

 quite saturated, the first effect was so small as to be much less, 

 than the error incidental to the graphical process, and I did not. 

 therefore take it into account. The second effect was also very 

 small ; but as in some cases it was nearly as great as Bender's, 

 estimated error, I took it into account in all the calculations. 



While Kohlrausch's solutions had at 1 8C both the constitu- 

 tion and the conductivity specified in his tables, Bender's solutions:, 

 had at 15 the constitution, and at 18 the conductivity ascribed 

 to them. I found that it did not appreciably affect the values, 

 found for a \ and 2 to regard the concentrations at 15 as being 

 the concentrations at 18, but that this approximation was, 

 inadmissible in calculating the conductivity, as in some cases it, 

 made a difference of about the same magnitude as Bender's 

 estimated error. Hence in the calculations, I took as the values. 

 of n l and 7i 2 , Bender's values multiplied by the ratio of the 

 volume of the solution at 15 to its volume at 18. As Bender 

 measured the thermal expansion of his solutions, his paper 

 furnishes the necessary data for this correction. 



The conductivities given by Bender as the results of his 

 observations are the actual results of measurement, and are thus 

 affected by accidental errors, which in some cases are considerable. 

 In order that his observations might be rendered comparable 

 with the results of calculation, these accidental errors must as 

 far as possible be removed. I therefore plotted all his series of 

 observations on co-ordinate paper, drew smooth curves through 

 them, and estimated as well as I could, in this way. the 

 accidental errors of the single measurements. The corrections 

 thus determined are given in the table below in the column 

 headed : Correction a. 



Bender himself draws attention to certain differences between 

 his observations of the conductivity of simple solutions of K Cl 

 and Na Cl, and those for solutions of the same strength con-~ 



