188 Analyfis of the Air. 



and it was the fame in the diftillation of 



Muftard-fecd. 



An account of some Experiments made 

 on Stones taken out of human Urine 

 and Gall Bladders. 



HAVIVG, while thefe Sheets were 

 printing off, procured by the favour 

 of Mr. Ranby 7 Surgeon to His Majeftys- 

 Houfhold, fome calculi humani, I made the 

 following Experiments with them, which I 

 ihall here infert, viz. 



I diflilled a calculus in the iron retort 

 (Fig. 38.) It weighed 230 grains, which is 

 fomething lefs in bulk than f of a cubick 

 inch : There arofe from it very briskly, in 

 diftillation, 516 cubick inches of elaftick Air, 

 that is, a bulk equal to 645 times the bulk 

 of the Stone 5 fo that above half the Stone 

 was raifed by the action of the fire into elaf- 

 tick Air $ which is a much greater propor- 

 tion of Air, than I have ever obtained by 

 fire, from any other fubftances, whether a- 

 nimal, vegetable or mineral. The remaining 

 calx weighed 49 grains, that is ^— part 

 of the calculus ; which is nearly the fame 



3 pro : 



