OF AQUEOUS SOLUTIONS.—BARNES. 133 
platinum wires to the ebonite covers. These electrodes were 
platinized in the solution proposed by *Lummer and Kurlbaum. 
The reduction factor by which the conductivities obtained in 
this cell are reduced to the standard employed by Kohlrausch, 
was obtained by comparing the value of the conductivities of 
two solutions of pure potassium chloride, twice recrystallized, 
of different concentrations, with values given by ?Kohlrausch 
for the same concentrations of the same salt. The ratio of 
Kohlrausch’s value to the observed value gives the reduction 
factor. It was always determined before and after a series of 
observations, and was found to be the same in value at both 
times. 
Solutions of different concentrations of each acid were pre- 
pared and carefully analysed. Fifty cubic centimetres of one 
of these solutions was placed in the electrolytic cell at a time, 
and two successive dilutions prepared in the cell by the addition 
of known volumes of water at 18°C. Then the other prepared 
solutions were introduced in order, and the same process of 
dilution repeated till a sufficient number of conductivity values 
had been obtained. In the case of mixtures, equal volumes 
(fifty cubic centimetres) of the constituent solutions were mixed 
at 18° C., and the mixture was then placed in the cell. 
For a more detailed description of some of the above instru- 
ments and methods, see my former paper on conductivity. 
Results of the Conductivity Observations on Simple Solutions. 
It is necessary for the determination of the regional con- 
ductivities (/) and the regional concentrations (C) in the 
mixture (see my former paper),? to draw curves showing the 
relation of conductivity to the concentration for each acid. In 
the case of one of the electrolytes, (hydrochloric acid was 
selected), the values of the conductivity must be multiplied by 
a constant before plotting, this constant being the ratio of the 
specific molecular conductivities at infinite dilution for the two 
1Wied. Ann., 66, 315, 1897. 
2Kohl. u. Holb., loc. cit., p. 159, tab. 2. 
3 Trans. N.S. Inst. Sci., 10, 113, 1899-1900. 
