I shall, therefore, surprise the Honourable J.T.

Maston when I tell him that he has been timid in his calculations, and I propose to double his 800,000 lbs.

of powder." "Sixteen hundred thousand pounds!" shouted J.T.Maston, jumping out of his chair.
"Quite as much as that." "Then we shall have to come back to my cannon half a mile long." "It is evident," said the major.
"Sixteen hundred thousand pounds of powder," resumed the Secretary of Committee, "will occupy about a space of 22,000 cubic feet; now, as your cannon will only hold about 54,000 cubic feet, it will be half full, and the chamber will not be long enough to allow the explosion of the gas to give sufficient impulsion to your projectile." There was nothing to answer.

J.T.Maston spoke the truth.

They all looked at Barbicane.
"However," resumed the president, "I hold to that quantity of powder.
Think! 1,600,000 pounds of powder will give 6,000,000,000 litres of gas." "Then how is it to be done ?" asked the general.
"It is very simple.