and Mr active Powers of various faline Suljlances . 27 
tity of each fort of oil of vitriol that was taken up by the 
alkali* 
Hence I fuppofed, that each of thefe quantities of oil of vi- 
triol of different denfities contained 3,55 gr. of acid, as they 
faturated the fame quantity of vegetable fixed alkali as i 1 gr. of 
fpirit of nitre, which contained that quantity of acid. 
I then endeavoured to find the fpecific gravity of the pure 
vitriolic acid in the fame manner as I before had that of the 
nitrous, as it cannot be had in the fhape of air unlefs united to 
fuch a quantity of phlogifton as quite alters its properties. The 
lofs of 6,5 gr. of oil of vitriol, whofe fpecific gravity is 1,^19 
is y^^ = 3,57 2 ; but as thefe 6,5 gr. contained, befides 3,55 
gr. acid, 2,95 of water, the lofs of this mu ft be fubtra&ed 
from the intire lofs, and then the remainder 0,622 is the lofs of 
the pure acid part in that ftate of denfity to which it is reduced 
by its union with water. The fpecific gravity therefore of the 
pure vitriolic acid in this ftate of denfity is = 5,707. But 
to find its natural fpecific gravity we muft find how much its 
denfity is increafed by its union with this quantity of water : 
and, in order to ohferve this, I proceeded as before with the 
nitrous acid. 6,96 gr. of oil of vitriol, whofe fpecific gravity 
was 1,771, contained 3,55 gr. acid, and 3,41 of water; then 
its fpecific gravity by calculation fhould be 1,726, for the lofs 
of 3,55 gr. acid is -—- = 0622 ; the lofs of 3,41 gr. water is 
*3? « § 
3,41 ; the fum of the lofles 4,032. Then, —— =17,261 ; 
therefore the accrued denfity is 1,771 - i, 726 = ,045. Taking 
this therefore from 1,819, * ts mathematical fpecific gravity will 
be 1,774, then the lofs of 6,5 gr. of oil of vitriol, whofa 
E 3 fpecific 
