IN DIFFERENT SALINE FLUIDS BY THE AID OF ELECTRICITY. 207 
The calculus when dry weighed 32 grains, so that the loss was 6 grains in 6‘‘ 10"'. 
The solution was chiefly on the cut surface of the calculus, which was in contact with 
the positive electrode. 
Thus it appeared that by increasing the intensity of the battery the solution of 
nitre acted more energetically. The calculus however was a very small one; it 
originally weighed 42^ grains only. One quarter of this however was dissolved. 
Experiment 6. — The addition of other substances to the nitre solution was then 
tried ; and first, phosphate of soda was employed. To each pint of the nitre solution 
two ounces of a saturated solution of phosphate of soda were added. A divided oxalate 
of lime calculus was taken which weighed 173 grains. The battery consisted of 
twenty pairs of plates. 
The action commenced at 9** 30'“a.m. and was continued to 12*" 49‘"a.m., the tem- 
perature of the solution being between 66° and 110°. 
The total time was 3** 19“. 
The calculus when dry weighed 17’2 grains, so that in 3’^ 19'" the loss was only 
1 grain. 
The calculus was exceedingly compact. There was no action whatever apparent 
at the negative or alkaline electrode which was on the upper and cut surface; the 
solution was of course alkaline throughout the whole time. The battery was in 
excellent action. 
Experiment 7. — Two ounces of a strong solution of bichromate of potash were then 
added to each pint of the nitre solution. The same calculus was taken ; it weighed 
1/2 grains. Twenty pair of plates were again used. 
The action began at 9'’ 30'"a.m. and was continued to 12’* 45"*a.m., the temperature 
being between 65° and 120°. 
The total time was 3’* IS"*. 
When the calculus was dry it weighed 170 grains, so that the loss in three hours 
and a quarter was only 2 grains. Apparently this was taken from the cut surface of 
the calculus. The external surface, which was exceedingly hard, was not attacked, 
though it was in contact with the positive electrode. Finding thus no success 1 
returned again to the nitre solution. 
Experiment 8. — The solution of nitre was taken of double the strength of that 
which had previously been used, that is, one-half saturated solution and one-half di- 
stilled water. I was desirous of knowing whether the oxalate of lime would be more 
soluble in this than in a weaker solution ; the battery and the calculus were the same 
as before. The calculus weighed 170 grains. 
The action began at 9’* 30'** a.m. and was continued to 12’* 47*** a.m. ; the temperature 
of the solution was between 64° and 110°. 
Total time vvas 3’* 17™. 
When dry the calculus weighed 167^ grains, so that the total loss in three hours 
and seventeen minutes was only 2^ grains. There was very slight action on the 
