with the dimensions of the cannon."

"Now, up to the present time," said Barbicane, "our longest guns
have not exceeded twenty-five feet in length. We shall
therefore astonish the world by the dimensions we shall be
obliged to adopt. It must evidently be, then, a gun of great
range, since the length of the piece will increase the detention
of the gas accumulated behind the projectile; but there is no
advantage in passing certain limits."

"Quite so," said the major. "What is the rule in such a case?"

"Ordinarily the length of a gun is twenty to twenty-five times
the diameter of the shot, and its weight two hundred and
thirty-five to two hundred and forty times that of the shot."

"That is not enough," cried J. T. Maston impetuously.

"I agree with you, my good friend; and, in fact, following this
proportion for a projectile nine feet in diameter, weighing 30,000
pounds, the gun would only have a length of two hundred and twenty-
five feet, and a weight of 7,200,000 pounds."

"Ridiculous!" rejoined Maston. "As well take a pistol."

"I think so too," replied Barbicane; "that is why I propose to
quadruple that length, and to construct a gun of nine hundred feet."

The general and the major offered some objections; nevertheless,
the proposition, actively supported by the secretary, was