1 8 8 Analyfts of the Atr. 
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. 
H AVIVG, while thefe Sheets were 
printing off, procured by the favour : 
of Mr. Ranby^ Surgeon to His Majefly s- • 
Houfholdy fome calculi humani, I made the j 
following Experiments with them, which I I 
(hall here infert, viz. 
I diftilled a calculus in the iron retort 
(Fig. 38.) It weighed 230 grains, which is 
fomething lefs in bulk than 4 of a cubick 
inch : There arofe from it very briskly, in 
diftillation, 5 16 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 adlion of the fire into elaf- 
tick Air 5 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- * 
