206 DR. BENCE JONES ON THE SOLUTION OF OXALATE OF LIME CALCULI 
of sulphate of soda might be determined. The weight of the calculus then was 
40 grains. 
The action commenced at 9^ 10“ a.m. and was continued to 1 p.m., the temperature 
of the solution being between 64° and 104°, 
The action recommenced at 2 ^ 5“ p.m. and was continued to 4‘' 30“ p.m., the tempe- 
rature being between 70° and 102°. 
Total time 6^ 15“. 
The battery was in good condition throughout the day. When the calculus was 
dry it weighed 38 grains, so that in six hours and a quarter only 2 grains had been 
dissolved. 
Comparing this with the previous experiment, there is no advantage in using the 
sulphate of soda instead of the nitrate of potash. 
I proceeded to try whether a solution of chloride of sodium would be more effica- 
cious than the sulphate of soda or nitrate of potash. 
Experiment 4.— The calculus was taken which had already been used in the 
previous experiments, in order that the comparative result might be as conclusive as 
possible. The chloride of sodium was dissolved in undistilled water, and the specific 
gravity of the solution was 1053-5. The battery was of the same strength as before. 
The action began at 9^ 30“a.m. and was continued to i p.M., the temperature of 
the solution being between 68° and 108°. 
The action recommenced at 2‘> 15“ p.m. and was continued to 4^^ 30“ p.m., the tem- 
perature being between 70° and 100 . 
Total time 5*' 45“. 
During the whole action much chlorine gas was evolved. The stone was perfectly 
bleached in places. When dry it weighed 37 grains. In five hours and three quarters 
only 1 grain was dissolved; thus it was evident that a solution of common salt was 
inferior to a solution of Glauber-salt or of nitre. In consequence of these experiments, 
it appeared most desirable to try whether the solution of nitre could be made still 
more active, either by increasing the strength of the battery, by adding other sub- 
stances to the solution of nitre, or by increasing the strength of the solution of nitre. 
For determining these questions the following experiments were made. 
Experiment 5. — The battery was increased to double the number of plates ; that 
is, to twenty pairs. The calculus was the same as before, and the solution of nitre 
had the specific gravity 1026. 
The action began at 9^' 35 a.m. and was continued to 1 p.m., the temperatui-e of tlie 
solution being between 67° and 130°. 
The action recommenced at 2 p.m. and was continued to 4'' 45™ p.m., the tempeia- 
ture being between 70° and 100°. 
Total time 6^^ 10™. 
The action of the battery diminished at one o’clock, so that the full action was 
only 3^ 25™. 
