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the Force of fired Gunpowder. 
As there are 15-^ parts of charcoal in 100 parts of gun- 
powder, in 1 cubic inch of gunpowder ( = 253.175 grains 
Troy,) there must be 38.989 grains of charcoal; and if we 
suppose ± of the apparent weight of this charcoal to be water, 
this will give 4.873 grains in weight for the water which exists 
in the form of moisture in 1 cubic inch of gunpowder. 
That this estimation is not too high is evident from the fol- 
lowing experiment. 1160 grains Troy of apparently dry gun- 
powder, taken from the middle of a cask, on being exposed 15 
minutes in dry air, heated to the temperature of about 200°, 
was found to have lost 1 1 grains of its weight. This shews 
that each cubic inch of this gunpowder actually gave out 2-^ 
grains of water on being exposed to this heat ; and there is no 
doubt but that at the end of the experiment it still retained 
much more water than it had parted with. 
If now we compute the quantity of water which would be 
sufficient, wheq reduced to steam under the mean pressure of 
the atmosphere, to fill a space equal in capacity to 1 cubic inch, 
we shall find that either that contained in the nitre which 
enters into the composition of 1 cubic inch of gunpowder as 
water of crystallization , or even that small quantity which 
exists in the powder in the state of moisture , will be much more 
than sufficient for that purpose. 
Though the density of steam has not been determined with 
that degree of precision that could be wished, yet it is quite 
certain that it cannot be less than 2000 times rarer than water, 
when both are at the temperature of 212 0 -. Some have sup- 
posed it to be more than 10,000 times rarer than water, and 
experiments have been made which seem to render this opinion 
not improbable; but we will take its density at the highest 
MDCCXCVII. O q 
