204 Mr. Thompson’s Experiments 
in a fecond ; and with the fame quantity of double proof * bat- 
tle powder (experiment N° 106) the velocity was 990 feet in a 
fecond. Now the fquares of thefe velocities, which, as we 
juft obferved, meafure the goodnefs of the powder, are to each 
other as 1 is to 1,2263, or nearly as 5 is to 6. 
With 218 grains of government powder, the mean ve- 
locity in four experiments (viz. the 40th, 4*^4 4 2 d> and 43a) 
was 1225 feet in a fecond ; and in the experiment N° 107. 
when the fame quantity of double proof battle powder was 
made ufe of, the velocity was 1380 in a fecond; and 
1225" is to 1380 as 1 t0 I ? 2 ^9 1, 
With 290 grains, or half the weight of the bullet in go- 
vernment powder in the 109th, 110th, 111th, and ii -th 
experiments, the mean velocity of the bullet was 1444 feet 
in a fecond ; but with the fame quantity of the battle powder 
(experiment N° 1 16.) the velocity was 1525 feet in a fecond ; 
1 444" is to 1525 , as 1 is to 1,1153- 
By taking a medium of thefe trials it appears, that double 
proof battle powder is better than government powder in pro- 
portion as 1,2036 is to 1, or nearly as 6 is to 5* 
But if, inftead of weighing the powder, we eftimate the 
quantity of the charge by meafurement, or the fpace it occupies 
in the bore of the piece, the comparative ftrength of battle 
powder will appear to be COnfiderably greater, or its ftrength 
will be to that of government powder nearly as 4 is to 3 ; for the 
grains of this better kind of powder being more compact and 
nearly of a fpherical form, a greater weight of it will lie in any 
* This is called tattle powder, not becaufe it is ufed in battle or in war ; but 
from Battle ) the name of a village in Kent, where that kind of powder is made. 
given- 
