( 2410 ) 
ter down violently, but fuddenly riling again, refted lo 
much below the Mark it flood at before firing, as was 
equal to the Quantity of fceming Air produced from it. 
The quantity of Gunpowder, uied in this Experiment, 
was one exact Grain Weight ; and I found the quantity 
of fpace the Water had detected, juft after the Explofion, 
was equal to the bulk ("nearly) of a Cubical Inch of 
Gunpowder , whofe Weight was 222 Grains: So that 
222 Grains Weight of the fame Powder, as foon as fir’d, 
Items to produce fomething to poflefs the fpace of fo 
many Cubical Inches of Air. Now whether the fpace 
deferted by the Water is polfefs’d by a Body of the 
fame Weight and Denfity, or is of the fame quality of 
common Air, I dare not determine ; Since an Experi- 
ment I have lately made, to try how much the heat 
produced by the Explofion of the Gunpowder, might con- 
tribute to the largenefs of the fpace difpolfefs’d by the 
Water, feems to conclude it otherwife .• For I found 
that when the Gunpowder had been fir’d an Hour, the 
Water had attended about J of the whole deferted 
fpace, which was in length about 2 f Inches, and was 
equal to about a Cube Inch in quantity ; The fpace in 
length was divided into 20 equal parts ; at two Hours 
after firing, it had afcended near d of the fame. By 
that time I judg’d it might become of an equal degree 
of Temperature with the outward Air : But ftill conti- 
nuing the Experiment, I found fto my great furprize) 
that two Hours after the laft Obfervation, the Water 
had reach’d to about Next Morning, which was 
at about 1 8 Hours diflance, I took notice it had arri- 
ved to near t;, or half of the firft deferted fpace. Thus 
continuing riling, I found that at the end of 12 Days, 
the Water had afcended fomething above s» of the fame. 
At 18 Days it had arrived to 19 of the 20 parts at firft 
deferted ; and at that Station it continued without al- 
teration for 8 Days ; So that the feeming real Air, pro- 
duced 
