1. I put a piece of a very hard _calculus_, which I shall call _x_, weighing 80 grains, in oystershell lime-water, renewing the lime-water every day, and keeping it in a heat between 90 and 106 degrees of Fahrenheit’s scale. After 20 days, I took out the _calculus_; and having set it by for some days, till it was become quite dry, I brushed away all the rotten part of it, which was reduced to a kind of chalky powder, and found that the undissolved part of it weighed 57 grains. 2. At the same time a piece of another _calculus_, _z_, weighing 15 grains, was, after a like infusion of 20 days in oystershell lime-water, reduced to 10 grains. 3. I put a piece of _z_, weighing 14 grains, in a solution of half an ounce of the internal part of Spanish soap in nine ounces of water, and every third day renewed the solution, which was kept in a heat of about 60 degrees. After 14 days, I found the undissolved part not to exceed 11 grains. 4. A piece of a white chalky _calculus_, _y_, weighing 30 grains, had near 4 grains of its substance dissolved, by being 14 days infused as above in a solution of soap. From Nº. 1. above, compared with Dr. Springsfeld’s Exper. (B), it appears, that the dissolving power of oystershell lime-water is to that of the Carlsbad water as 23 to 18, supposing the _calculi_ used in these experiments to have been equally easy to dissolve. Nº. 3. compared with Dr. Springsfeld’s Exper. (A), shews, that the dissolving power of a solution of the inner part of Spanish soap, in a heat of 60 degrees, is to that of the Carlsbad water, in a heat of 96 degrees, as 15 to 14. From Nº. 4. compared with (A), the dissolving power of soap is to that of the Carlsbad water only as 4 to 6; but it is probable, that had the solution of soap been kept in a heat of 96 degrees, its dissolving power would, even in this experiment, have nearly equalled that of the Carlsbad water. It may, perhaps, be worth while to observe, that a piece of the white chalky _calculus_ of Nº 4. was not in the smallest degree dissolved by lying in lime-water 20 days. 5. In Exper. 19. of my Essay on the Virtue of Lime-water, a piece of a _calculus_, _b_, weighing 31 grains, lost 7 grains by being infused 36 hours, in a heat of above 100 degrees, in very strong oistershell lime-water. And in the same water, of a moderate strength, another piece of _b_ lost, in the same time, 5 grains. In this last experiment, the lithontriptic virtue of lime-water appears to be stronger than in Nº. 1. and 2. above; and greatly exceeds that of the Carlsbad water in Dr. Springsfeld’s Exper. (A) and (B).