273 
1906 - 7 .] Optical Rotation of Two Salts. 
part of* the liquid in the stem. It was then adjusted, wiped dry, and 
weighed. The resulting densities were found to be — 
o o 
Concentration of the 
Density of the 
Molybdate in the Solution. 
Solution at 25° C. 
0 
1-0260 
i 
8 
1-0318 
1 
9 
T0414 
I 
1-0598 
These are plotted in fig 1. 
A test of the accuracy of the measurements is afforded by comparing the 
figures obtained in two completely independent experiments which were 
made on one of the solutions. The first experiment gave the density as 
1 03178, the second as 103180, a result which seems very satisfactory. 
Fig. 1. 
2. The Conductivity Measurements. 
These were carried out by Kohlrausch’s method. The solution was 
contained in a U tube also placed in a thermostat bath. The metre wire 
VOL. xxvii, 18 
