208 DR. BENCE JONES ON 
THE SOLUTION OF OXALATE OF LIME CALCULI 
external surface of the stone which was in contact with the positive electrode. The 
cut surface around the nucleus appeared most acted on. The very frequent c anges 
of the solution consequent on the resistance being lessened, led to the adoption of a 
continuous stream of solution, , , 
Experiment 9.— It appeared from the last experiment, that by doubling the strength 
of the solution no corresponding increase in the action on the calculus occurred. To 
be still further convinced, the same calculus with the same battery was taken, and a 
solution was used of only half the strength of the previous one; that is, it was one- 
fourth saturated solution of nitre and three-fourths water, by means of a small tube 
siphon which carried off an ounce of fluid in twenty seconds, and a vessel with a 
stopcock which supplied fresh fluid. The temperature of the solution in which the 
calculus was kept remained about 92°, never rising higher than 96°. 
The action began at 10 a.m., the temperature then was 64°. 
The action was stopped at 12^' 50™ a.m., the temperature then was 92°. 
Total time 2^^ 50™. . 
The calculus when dry weighed 165 grains, so that in two hours and fifty minute.v 
of continuous action 2^ grains only were dissolved. By comparing this experiment 
with the previous one, it is so far certain, that, by increasing the strength of the solu- 
tion of nitre, no more action on the calculus was obtained.^ The next question was 
whether, by increasing the strength of the battery, the solution of the oxalate of lime 
would more rapidly take place. ^ . 
Experiment 10.— The same calculus was used as before ; it weighed now 16o grams. 
The solution of nitre was the same strength as in the last experiment. The battei\ 
was increased to forty pairs of Grove’s plates. The temperature was kept down 
by about six pints of nitre solution, and as the liquid passed out of the decomposing 
Hass it was cooled by ice, and then returned to the reservoir. The temperature was 
thus kept throughout the whole experiment from rising above 102°; one ounce lan 
through in five seconds. 
The action began at 9^' 25™ a.m., the temperature then was 66°. 
The action began at 9’' 47™ a.m. A voltameter placed in the circuit showed that 
1 cubic inch of mixed gases was evolved in twenty seconds. 
The action was stopped at 12‘‘ 25™ a.m., the temperature throughout was between 
98° and 102°. 
The total time 3'’. 
The calculus when dried weighed 160 grains, so that the total loss in tliiee louis 
was only 5 grains. There were very slight marks of action on the external surface. 
The hardness of this surface was between that of fluor and calc spar; Mi. Tennant 
placed it for me at 3-5. 
The current was continuous for three hours; the battery was in perfect ouei 
though diminishing in action towards the end of the experiment. 
