332 ON THE CALCULATION OF THE CONDUCTIVITY OF 
the conductivities at regular intervals were read off and divided 
by the value of ps for that salt, Kohlrausch’s values being 
employed, viz., for sodium chloride 1030 and for barium chloride 
1150, the conductivity unit being the same as hitherto. The 
quotients thus obtained were taken to be the values of the ionic 
concentrations. These last, divided by the corresponding dilu- 
tions, were plotted against the dilutions, and from the curves 
thus obtained, by Prof. MacGregor’s graphical process, the” 
common value of the ionic concentration of the electrolytes in 
their respective regions in the mixture and their dilutions 
throughout these regions, were found. The products of the 
latter values and the former gave the corresponding ionization 
coefficients. The plotting was done on very various scales as 
was necessary in order to plot all the curves so that readings 
could be made to0.1 per cent. The calculation of the conductiv- 
ity required three readings from the curves representing ionic 
concentration and dilution. Supposing these curves correct, the 
error involved in making these readings might amount to 0.15 or 
0.2 per cent. 
Results of Calculations. 
The following table gives the results of the calculation of the 
conductivity of the mixtures. The first two columns give the 
concentration in gramme-equivalents per litre of the NaCl and 
BaCl, solutions before mixing, their volumes being then equal. 
The third, fourth, and fifth columns give the ionic concentrations 
and the dilutions of each salt in its portion of the mixture, each 
of these heing expressed in terms of the units and quantities 
before described. The sixth and seventh columns give the 
specific conductivity at 18°C, in terms of 10~° times the specific 
conductivity of mercury as calculated, and the value of the same 
determined experimentally. The eighth column gives the excess 
of the calculated over the measured value expressed in fractions 
of 1 per cent of the latter. 
