MIXTURES OF ELECTROLYTES—MACGREGOR. ALS 
mixtures, we must determine what the conductivities of Bender’s 
mixtures would have been if Kohlrausch had prepared and 
measured them. To find this out as nearly as possible, I plotted 
the data of the above table with Bender's conductivities as 
abscissee, and the differences between them and Kohlrausch’s 
corresponding values as ordinates, and drew a smooth curve 
through the points. By the aid of this curve I determined the 
correction 6 of the table given below. This correction is of 
course a more or less doubtful one; for it is not certain that the 
observations on mixtures suffered from the same unknown 
source of error as the observations on simple solutions. It 
seems probable however that they did; and the results of the 
table given below would appear to render it almost certain. 
It nay be well in one case to give an example of the mode 
of calculation. We may take for this purpose the mixture of 
sulutions containing each 1 gramme-molecule of salt. It is 
found by the graphical process that the value of a/V for this 
mixture is 0.718 gramme-molecules per litre and that the dilu- 
tions in the mixture are 0.937 and 1.063 litres per gramme- 
molecule for the Na Cl and K Cl respectively. The densities of 
the constituent solutions were 1.0444 and 1.0401 respectively, 
and that of the mixture 1.0422. The expansions per unit volume 
between 15° and 20° were 0.0013569 and 0.0012489 respectively. 
The values of the conductivity at infinite dilution, I took to be 
1028 and 1216 respectively, according to Kohlrausch’s observa- 
tions. Hence the conductivity of the mixture 
, 2x 1.0422 (* x 0.718 x 0.937 x 1028 1 x 0.718 x 1.063 x 1216 
nee : os et O! = a a 2 
k=% 30815 1+0.6x 0.00136. * ~ 140.6x 0.00125 ) oll 
Bender’s observed value (he used the same standard as 
Kohlrausch) was 814. To this a correction of about—3 must 
be applied to make the observation agree with the others of the 
same series (correction @) and a correction of about—3 to make 
it comparable with a calculated value based on Kohlrausch’s 
data (correction b). Bender’s reduced value is thus 808, which 
differs from the calculated value by 1.2, or 0.15 per cent. 
