MIXTURES OF ELECTROLYTES.—MCcINTOSH. 125 
To determine the accuracy of the volumetric analysis, a 
solution of sodium chloride was prepared, containing a known 
quantity of the pure fused salt. The results of the analyses 
were found to be correct to 0.1 per cent. 
Specific Gravity Determinations. 
The object of specific gravity determinations was the finding 
of p in the above expression for the conductivity. For this 
purpose it was necessary to find the specific gravity to the third 
decimal place only. Hence the determinations were made with 
a Mohr-Westphal balance which read to the fourth decimal 
place, and might be trusted in the third. 
In all the mixtures examined p was found to be practically 
equal to unity. 
Preparation of the Mixtures. 
A 50 ¢.¢ pipette which had been carefully washed, and 
stood on filter-paper for some time, was rinsed out several times 
with one of the constituents of the intended mixture, whose 
composition and specific gravity had been determined. The 
pipette was filled to the mark, and the solution run into a clean 
and dry bottle. The pipette was then washed, and the other 
constituent placed in the bottle as before, care being taken to 
use the pipette in exactly the same manner in both cases. All 
mixtures were made at 18°C. and the same pipette was used for 
both solutions, in order that the mixture might consist of exactly 
equal volumes of them. 
The conductivities of solutions were found to increase on 
standing, which was doubtless due to portions of the glass being 
dissolved. The conductivities were therefore measured as soon 
after the solutions were made up as possible. 
Capacity of the Electrolytic Cell. 
To find the factor which would reduce the observed conduc- 
tivities to the standard employed by Kohlrausch, viz., the 
conductivity of mercury at 0°C, the following simple solutions 
of potassium and sodium chloride were analysed, and their con- 
ductivities measured : 
