AQUEOUS SOLUTIONS.—ARCHIBALD. 319 
are given in Table I. Similar data for Sodium Sulphate are 
given in my previous paper.* As the above data, in the case of 
the Potassium Sulphate, are better than those given in my 
previous paper, I have thought it well to make new observations 
and calculations on these mixtures. Concentrations, dilutions, 
concentrations of ions, and conductivities, are expressed in terms 
of the same units as in Table IT. 
The results of this table show that the calculated and 
observed values of the conductivity of mixtures of equi- 
molecular solutions of Potassium and Sodium Sulphates agree 
within the limits of observational error, at least up to a concen- 
tration of 1 gramme-equivalent per litre. The observations of 
my former paper, in which the mixtures examined were not 
equi-molecular in concentration, gave a similar result. 
Conclusions. 
An examination of ‘Tables II, V, and VI, will show, that in 
the case of the Potassium-Copper sulphate solutions, the differ- 
ences between the observed and calculated values of the 
conductivity, are all of the same sign and positive from a con- 
centration of 0.1 to one of 1.294 equivalent gramme-molecules 
per litre, that the differences increase with the concentration, 
reaching in the case of the strongest solution examined 
6.58 per cent. 
For the mixtures of Sodium and Potassium Sulphates and 
of Zine and Copper Sulphates examined, the difference for a like 
concentration are not greater than 0.30 per cent. Now, errors 
are caused in the calculations by taking the ionization coeffi- 
cients to be the ratios of the specific molecular conductivity at 
infinite dilution, which is rigorously true only for infinitely 
dilute solutions, and also by taking the value of the specific 
molecular conductivity at infinite dilution for an electrolyte in a 
mixture to be the same as the value found by observations on 
the simple solutions, which is strictly true only for infinitely 
* Loc. cit. 
