394 E ) r . ingenhousz’s Account of a 
and one of fulphur; when feven parts of nitre are ufed, 
it is called poudre d' artifice. 
The celebrated Mr. John bernouilli calculates the 
denfity of the air contained in a folid flate in gunpowder 
to be of what this fluid is when it conflitutes a part 
of our atmofphere. But he does not confider this air as 
exifting in all the component ingredients of the gun- 
powder, but chiefly in the nitre : and Count saluce fup- 
pofes, that that part of the gunpowder which contains 
this air conflitutes a confiderable part of its bulk (though 
fomewhat lefs than the half). Let us now fuppofe, that 
part of the gunpowder which contains this air to be not 
much lefs than the half of the whole mafs (for it would 
be difficult to demonftrate accurately to what proportion 
of the whole mafs this part amounts in reality). On this 
fuppofition we fhall find, that the whole mafs of gunpow- 
der contains a quantity of air in a folid Hate which is re- 
duced in bulk to near or, in other words, that one 
fquare inch of gunpowder contains near 500 fquare inches 
of air; which being heated in the moment of inflamma- 
tion will expand to four times its diameter; fo that ac- 
cording to this calculation gunpowder muffc expandin the 
moment of explofion to near 2000 times its own bulk. 
It feems very probable, that this calculation of Mr. 
bernouilli is much nearer the truth than that of 
Mr. 
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