upon Gun-powder, &c. 315 
der which was defigned for great guns and mortars was weaker 
than thole which were intended to be ufed in fmailer pieces : 
for if there is any foundation for thefe conjectures, it is cer- 
tain, that the weakeft powder, or the heavieft in proportion to 
its elaftic force, ought to be ufed to impel the heavieft bullets, 
and particularly in guns that are imperfectly formed, where the 
vent is large, and the windage very great* 
I am perfectly aware, that an objection may here be made, 
viz. that the elaftic fluid, which is generated from gun-powder, 
muft be fuppofed to have the fame properties .very nearly, 
whatever may be the proportion of the feveral ingredients, and 
that therefore the only difference there can be in powder is, 
that one kind may generate more of this fluid, and another lefs ; 
and that when it is generated, it aCts in the ftime manner, and 
will alike efcape, and with the lame velocity, by any paflage it 
can find. But to this I anfwer, though the fluid’ may be the 
fame, as undoubtedly it is, and though its denfity and elafti- 
city may be the fame in all cafes at the inftant of its generation, 
yet in the explofion, the elaftic and un-elaftic parts are fo mixed 
and blended, that I imagine the fluid cannot expand without 
taking the grofs matter along with it, and the velocity with 
which the flame ifliies out at the vent is to be computed from 
the elafticity of the fluid, and the denfity or weight of the fluid' 
and the grofs matter taken together, and not limply from, 
the elafticity and denfity of the fluid. If antimony in an’ im- 
palpable powder, or any other heavy body r was intimately 
mixed with water in a veflel of any kind, and kept in fufpenfion 
by fhaking or ftirring them about ; and if a hole was opened 
in the fide or bottom of the veflel, the water would not run 
out without taking the particles of the folid body along with 
it. And in the fame manner I conceive the folid particles that 
remain 
