3Q2 Dr. ingenhousz’s Account of a 
The learned Count saluce remarks r '\ that the elaftic 
air generated by the inflammation of gunpowder occu- 
pies, when cold, 222 times the bulk of the powder, 
which agrees, as he finds, with the computation made 
by Meff. hauksbee, amontons, and belidor. This 
calculation he confirms in the Melanges de Pbilofo- 
phie et des Mathematiques de la Societe Roy ale de Turin, 
which is a continuation of the former work. He is of 
opinion, that this elaftic fluid is of the fame nature with 
common air (which was likewife the opinion of Dr. 
hales); and that the prodigious force of gunpowder de- 
pends upon the adfion of the fire on all its parts, by 
which this fluid exercifes all the force of its elafticity. 
The extrication of fuch a con fider able quantity of a 
permanent elaftic fluid by the firing of gunpowder has 
been put to a particular ufe by feveral philofophers. 
The celebrated Mr. de la condamine gives an ac- 
count of a brafs air gun contrived by one Mr. maty, of 
Turin; which he loaded with air condenfed by firing 
in it two ounces of gunpowder, which, by its inflamma- 
tion, let loofe fuch a quantity of air as was fufficient to 
fhoot a leaden bullet fixty paces, and to repeat the procefs 
(b) Mifcellanea Philofophieo-Mathematka Socktatis privat* Taurine nfis, 
y. 125. 
eighteen 
