Anaiyfis of the Air. i6j 
was wanting, upon weighing this veflel a- 
gain, was equal to the bulk of the new ge- 
nerated Air. I chofe to meafure the quan- 
tities of Air, and the matter from whence it 
arofe, by one common meafure of cubick 
inches, eftimated from the fpecifick gravi- 
ties of the feveral fubftances, that thereby 
the proportion of one to the other might 
the more readily be feen. 
I made ufe of the following means to 
meafure the great quantities of Air, which 
were either raifed and generated, or abforb- 
ed by the fermentation ariftng from the 
mixture of variety of folid and fluid fub- 
ftances, whereby I could eaftly eftimate the 
furprizing effeds of fermentation on the 
air, viz . 
I put into the bolthead b (Fig. 34.) the 
ingredients, and then run the long neck of 
the bolthead into the deep cylindrical glafs 
ay , and inclined the inverted glafs ay> and 
bolthead almoft horizontally in a large vef- 
fel of water, that the water might run in- 
to the glafs a y% when it was almoft up to 
a the top of the bolthead, I then immerfed 
the bottom of the bolthead, and lower part 
y of the cylindrical glafs under water, raid- 
ing at the fame time the end a uppermoft* 
M 4 Then 
