Now this is necessary to be known in order to understand the importance of the question submitted to the committee.
Thus a litre of gunpowder weighs about 2 lbs.; it produces, by burning, about 400 litres of gas; this gas, liberated, and under the action of a temperature of 2,400 deg., occupies the space of 4,000 litres.

Therefore the volume of powder is to the volume of gas produced by its deflagration as 1 to 400.

The frightful force of this gas, when it is compressed into a space 4,000 times too small, may be imagined.
This is what the members of the committee knew perfectly when, the next day, they began their sitting.

Major Elphinstone opened the debate.
"My dear comrades," said the distinguished chemist, "I am going to begin with some unexceptionable figures, which will serve as a basis for our calculation.

The 24-lb.