Analyjis of the Ah\ 157 
rations, into the nature of a fluid, too fine 
to be the objed of our light, mufl: be by 
finding out fome means to eftimate what 
influence the ufual methods of analyfing 
the animal, vegetable and mineral kingdoms, 
has on that fubrile fluid 5 and this I effected 
by affixing to retorts and boltheads hydro- 
ftatical gages in the following manner, viz,. 
In order to make an eftimate of the quan- 
tity of Air, which arofe from any body by 
diftillation or fulion, I firft put the matter 
which I intended to diftill into the fmall re- 
tort r (Fig. 33.) and then at ^cemented 
faft to it the glafs veffel a by which was very 
capacious at by with a hole in the bottom, 
I bound bladder over the cement which was 
made of tobacco-pipe clay and bean flower, 
well mixed with fome hair, tying over all 
four fmall flicks, which ferved as fplinters 
to ftrengthen the joynt 3 fometimes, inftead 
of the glafs veffel aby \ made ufe of a large 
bolthead, which had a round hole cut, with 
a red hot iron ring at the bottom of it 5 
through which hole was put one leg of an 
inverted fyphon, which reached up as far 
as 2;. Matters being thus prepared, holding 
the retort uppermoft, I immerfed the bolt- 
head 
