C 1 
--^DESCRIPTION OF THE APPARATUS; 
which is of glafs, and conhfts of three veiTels as (A^. 
B, C), fig. I. 2. 3. The glaflTes are. accurately fitted to 
each other, and at the joints are impervious both to air 
and water. The glafs (A) is defigned for the effervefcing 
fubftances.. The vefiel (B) is to contain the water that 
is to be impregnated with air. In the lower part of the 
glafs (B) is placed an ivory valve, furrounded with cork, 
as in fig. 4. The cork (a).h fitted to the bottom of the 
glafs (B), and has through it an hole, to receive the part 
(b) oi the ivory valve. On the broader part of this piece, 
(.b) is placed a moveable piece ( c),. The furfaces of thefe 
pieces are fo accurately ground, that, when applied to 
each other, no fluid whatever can pafs between them. 
The moveable part (c)\% fecured on the part (b) hy the 
cover which is fo conftmcfled, as to allow the piece. 
(c) fome motian, and this cover has like wife holes to 
give paffage to the air that fliall raife the moveable piece. 
[c). The glafs (,C) ferves two purpofes; it confines the. 
air on the furface of the water in.(B), and at the fame, 
time prevents all danger, of explofion by allowdiig the. 
water to give place to the afeending air.. 
THE PROCESS,. 
As chalk and oil of vitriol are capable, of producing 
the defired efFervefcence,,and are the mofl: eligible on ac- 
count of their cheapnefs, I fliall, in deferibing the pro- 
cefs, mention only thefe two ingredients. Variety of other 
fubftances 
