A litre of gunpowder weighs about 2 lbs.; during combustion it produces 400 litres of gas. This gas, on being liberated and acted upon by a temperature raised to 2400 degrees, occupies a space of 4000 litres: consequently the volume of powder is to the volume of gas produced by its combustion as 1 to 4000. One may judge, therefore, of the tremendous pressure of this gas when compressed within a space 4000 times too confined. All this was, of course, well known to the members of the committee when they met on the following evening.
The first speaker on this occasion was Major Elphinstone, who had been the director of the gunpowder factories during the war.
THE INVENTION OF GUNPOWDER BY THE MONK SCHWARTZ.
"Gentlemen," said this distinguished chemist, "I begin with some figures which will serve as the basis of our calculation. The old 24-pounder shot required for its discharge 16 lbs. of powder."
"You are certain of the amount?" broke in Barbicane.
"Quite certain," replied the major. "The Armstrong cannon employs only 75 lbs. of powder for a projectile of 800 lbs., and the Rodman Columbiad uses only 160 lbs. of powder to send its half-ton shot a distance of six miles. These facts cannot be called in question, for I myself raised the point during the depositions taken before the Committee of Artillery."
"Quite true," said the general.
"Well," replied the major, "these figures go to prove that the quantity of powder is not increased with the weight of the shot; that is to say, if a 24-pounder shot requires 16 lbs. of powder;—in other words, if in ordinary guns we employ a quantity of powder equal to two-thirds of the weight of the projectile, this proportion is not constant. Calculate, and you will see that in place of 333 lbs. of powder, the quantity is reduced to no more than 160 lbs."
"What are you aiming at?" asked the president.