( 547 ) 
at all kindle the Powder , but I made it only beil and emit flore 
of fmoke. 1 had put a Gage in the fame Recipient, by means 
whereof I obferved, that all that fmoke produced no Air ; for the 
Quickfilverdid not rife in the Tube. I noted alfo, that this 
fmoak falling upon the Paft-board, on which 1 had put the Pow 
der, appeared yellow of thecolourof Brimftone» After that , I 
took cue the Powder that remain d, being like ablackmafs, and 
having put it upon burning Coals, I faw it burned as doth Sale- 
Peter j and fo it appeared, that the fulphur was aimoft all exhaled. 
I was willing to reiterate this Experiment, and I thenfaw,tha£ 
the Powder, afcer boiling, fuming, and being kindled grain by 
grain, (as in the firft Experiment,) at laft flaftes out all at once, 
when one hath the patience to hold the fire to it with a Burning- 
glafs. And when the fumes are grown clearer, you may fee needles 
of Saltpeter fticking to the fides of the Receiver. 
Another time, I put the weight of 12 or 15 gram of Powder 
in a glafs ftaped like a Capping glafs , capable to hold 14 ounces 
of water, and having put fire to it, 1 made the Powder boil and 
fmoak as ufually. Afterwards , feeing that the corns began to 
crackvcry near one after another ; I then took away the burning 
Concave, for fear allfiiould be kindled together : But it was al- 
ready too late; for, the corns did continue to crack longer than 
a fecondof time, and at laft a4l kindled , though there was then 
nothing left to heat them but the fire which they bad kept within 
ihemfelves. The Receiver was lifted up above a foot high, with- 
out breaking. 
Another time, I put the weight of \Z grains o{ Powder, to- 
gether with a G^^^ , into a Receiver holding fcven pound watery 
and I faw, that the Powder was more difficult to be kindled, 
than in fmall Receivers. Yet ac length it was kindled altogether, 
and made the Quickfilver rife to the height of an inch and a half in 
theG^^^; and I am very well affured, that all that Air was not 
come from without 5 for that part of the Receiver, to which the 
Cover is applied, bad al waies been under water. 
From what I have been relating, it may be concluded , that 
&\ttt\sdi fifth part of Air in Gunpowder ; fuppofing, as other 
Experiments do fliew i that Air is about a thoufand times lighter 
than Water. For, in this Experiment , the Mercury did rife to 
the eighteenth pdLTt o( the height where the Air commonly fuflains 
B b b b it 5 
