2 90 Count Rumford's Experiments to determine 
A doubt might possibly arise with respect to the existence 
of a sufficient quantity of water in gunpowder, to fill the space 
in which the powder is fired, with steam, at the moment of the 
explosion ; but this doubt may easily be removed. 
The best gunpowder, such as was used in my experiments, 
is composed of 70 parts (in weight) of nitre, 18 parts of sul- 
phur, and 16 parts of charcoal; hence 100 parts of this powder 
contain 67^ parts of nitre, 17-^ parts of sulphur, and of char- 
coal 15^ parts. 
Mr. Kirwan has shown that in 100 parts of nitre there are 
7 parts of water of crystallization; consequently, in 100 parts 
of gunpowder, as it contains 67^ parts of nitre, there must b^ 
4 -nrcro P arts of water - 
Now as 1 cubic inch of gunpowder, when the powder is well 
shaken together, weighs exactly as much as 1 cubic inch of 
w r ater at the temperature of 55 0 F. namely 253.175 grains Troy, 
a cubic inch of gunpowder in its driest state must contain at 
least 1 Oj Vo o grains of water; for it is 100 to 4.711, as 253.175 
to 10.927. But besides the water of crystallization which exists 
in the nitre, there is always a considerable quantity of w r ater 
in gunpowder, in that state in which it makes bodies damp or 
moist. -Charcoal exposed to the air has been found to absorb 
nearly | of its weight of water ; and by experiments I have 
made on gunpowder, by ascertaining its loss of weight on 
being much dried, and its acquiring this lost weight again 
on being exposed to the air, I have reason to think that the 
power of the charcoal, which enters into the composition of 
gunpowder, to absorb water remains unimpaired, and that it 
actually retains as much water in that state, as it would retain 
were it not mixed with the nitre and the sulphur. 
