( 240 9 ) 
II. An Account of an Experiment, touching 
the Quantity of Air produced from a cer- 
tain Quantity of Gunpowder Fired in 
common Air, hy A/r.F.Hauksbee,! 7 .^.^. 
I Took a fine Glafs Tube about 36 Inches long, the 
Diameter of its Bore about three quarters of an 
Inch : Its upper Orifice had a Brafs Ferrei foder’d 
to a Screw cemented on it, to which was icrew’d a 
Cock. The lower or bottom part was naked and open 
( without the Bladder made ufeof when I made the Ex- 
periment before the Society, for I fince found that to be 
need lefs ) : near the upper part of this Tube within, was 
fixt a piece of Cork, noch’d on it Edges, to give the 
greater liberty for the Explofion to vent it fell'. The 
Cork had a fmall Cavity in its middle, the better to re- 
ceive and hold the Gunpowder, which was let down on 
it, through a fmall Glafs Funnel, before the Cock was 
fcrcw’d on. In this manner the lower Orifice was 
plung’d under the Surface of a Veflel of Water ; the 
Cock being then fcrew’d on and open, it was eafxe, by 
fucking at it with ones Mouth, to remove the inward 
Air, whereby the Preffure of the outward Air would 
raife the Water in it to any determinate height.- The 
Tube before being meafured by an accurate Cubical 
Inch, and graduated by a File on its outfide. When 
the Water had afcended to the defign’d Mark by the 
prementioned Means, the Cock was turn’d, which fuf- 
pended it there : Then the Focus of a burning Glafs be- 
ing call on the Powder, it foon fir’d, blowing the Wa- 
14 X ' ter 
