2 6 Mr. kirwan’s Experiments , &c. the fpecific Gravities 
the few grains wanting of 213 gr. may be accounted for from 
the abforption of the water in which he received the airs, and 
by allowing for that frill remaining in the yellow fublimate. 
OF O I L OF VITRIOL. 
The oil of vitriol I made ufe of was not perfectly dephlo- 
gifricated ; but though pale yet a little inclined to red. It con- 
tained fome whitifh matter, as I perceived by its growing milky 
on the affufion of pure difrilled water. How far this may alter 
the refult of the following experiments I have not tried ; but 
believe it to be as pure as that which is commonly ufed in all 
experiments, and therefore the fitted; for my purpofe. 
To 2519,75 gr. of this oil of vitriol, whofe fpecific gravity 
Was 1,819, I gradually added 180 gr. of diddled water , v and 
fix hours after found its fpecific gravity to be 1 ,77 1 . 
To this mixture I again added 1 78,75 gr. of water, and found 
its fpecific gravity, when cooled to the temperature of the at- 
mofphere, to be 1,719 ; it was then milky. 
I then faturated the fame quantity of the oil of tartar above 
mentioned with each of thefe forts of oil of vitriol in the 
manner already mentioned, and found the faturation to be ef- 
fected (taking the medium of five experiments) by 6,5 gr. of 
that whofe fpecific gravity was 1,819; by 6,96 gr. of that 
whofe fpecific gravity was 1,771 ; and by 7,41 of that whofe 
fpecific gravity was 1,719. 
I was obliged to add a certain proportion of water to each of 
thefe forts of oil of vitriol; for when they were not diluted, I 
perceived that part of the acid was phlogidicated, and went off 
with the fixed air ; but knowing the quantity of water that was 
added, it was eafy to find, by the rule of proportion, the quan- 
tity 
