the Force of fired Gunpowder. 245 
French, and very fine grained : and it was all taken from the 
same parcel. Care was taken to dry it very thoroughly, and 
the air of the room in which it was weighed out for use was 
very dry. The weights employed for weighing the powder 
were German apothecary’s grains, 104.8 of which make 100 
grains Troy. I have reduced the weights employed to confine 
the elastic vapour generated in the combustion of the powder 
from Bavarian pounds, in which they were originally expressed, 
to pounds avoirdupois. The measures of length were all taken 
in English feet and inches. The experiments were all made in 
the open air, in the court-yard of the arsenal at Munich ; and 
they were all made in fair weather, and between the hours of 
nine and twelve in the forenoon, and two and five in the after- 
noon ; but the barrel was always charged, and the extremity 
of the bore closed by its leather stopper, in the room where 
the powder was weighed. In placing the barrel upon the 
block of stone, great care was taken to put it exactly under 
the centre of gravity of the weight employed to confine the 
generated elastic vapour. Upon applying the red-hot ball to 
the vent tube, and fixing it in its place by its lever which sup- 
ported it, the explosion very soon followed. 
When the force of the generated elastic vapour was suf- 
ficient to raise the weight, the explosion was attended by a 
very sharp and surprisingly loud report ; but when the weight 
was not raised, as also when it was only a little moved, but 
not sufficiently to permit the leather stopper to be driven quite 
out of the bore, and the elastic fluid to make its escape, the 
report was scarcely audible at the distance of a few paces, and 
did not at all resemble the report which commonly attends 
the explosion of gunpowder. It was more like the noise 
K k 2 
