C tf$ ) 
Nitre by it (elf in a Glafs, leaving a (mall hole in the 
top to prevent its burfting, and gave it fo great a heat, 
that the Nitre loyled, and found in the upper part of 
the Glafs a very tranfparent fluid matter, or Oyl, which 
at another time was curdled ugether in irregular Fi- 
gures, and (luck to the Gla(s. 
Not fully fatisfied herewith, I repeated the Experi- 
ments with the powder, and immediately after its blow- 
ing up, I viewed the Glafs with a Microfcope, and 
could then difcern the very fuddain change or (hooting 
of the Globular Particles of the Nitre into Stxangular 
Salts, and that all at once. The number of thele Salt- 
Peter Particles afforded by one Corn of Powder, is in- 
conceivably great, befides thofe of the Sulphur and 
Coal. Thefe were belt feen when I fired but one Corn ; 
for when there were more fired, the greater quantity of 
Nitre blew up fo much of the Sulphur and Coal, that 
the change and (hooting of the Salts could not be fo 
well feen. If I fired the Powder with Heat from below, 
the Coal and Sulphur would be blown up; but if with 
Heat from above, but few Particles of the Coal, and 
yet fewer of the Sulphur would be forced up. 
Next I fired one,two,and three Corns of Powder in fe- 
veral clofed Glaffes, and differing them to cool, I opened 
them (fome after 4 or 5 days) and found always com- 
preft Air therein , which flew forcibly out. That I 
might know the quantity of this generated Air, I open- 
ed (bme of them after (uch a manner, that the Air con- 
tained therein iffiied into a Bolt-head with a narrow 
Neck, which was filled with Water, which, as the Air 
ruflied in, was forced out ; by which Experiment I found 
the Air comprefs'd eight times w 7 hat it was before ; or, 
which is the fame thing, when at liberty took up eight 
times the room it did before, 
Not 
