Chapter 8 - Page 2

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
definitely adopted.

"But," said Elphinstone, "what thickness must we give it?"

"A thickness of six feet," replied Barbicane.

"You surely don't think of mounting a mass like that upon a
carriage?" asked the major.

"It would be a superb idea, though," said Maston.

"But impracticable," replied Barbicane. "No, I think of sinking
this engine in the earth alone, binding it with hoops of wrought
iron, and finally surrounding it with a thick mass of masonry of
stone and cement. The piece once cast, it must be bored with
great precision, so as to preclude any possible windage. So there
will be no loss whatever of gas, and all the expansive force of
the powder will be employed in the propulsion."

"One simple question," said Elphinstone: "is our gun to be rifled?"

"No, certainly not," replied Barbicane; "we require an enormous
initial velocity; and you are well aware that a shot quits a
rifled gun less rapidly than it does a smooth-bore."

"True," rejoined the major.

The committee here adjourned for a few minutes to tea and sandwiches.

On the discussion being renewed, "Gentlemen," said Barbicane,
"we must now take into consideration the metal to be employed.
Our cannon must be possessed of great tenacity, great hardness,
be infusible by heat, indissoluble, and inoxidable by the
corrosive action of acids."

"There is no doubt about that," replied the major; "and as we
shall have to employ an immense quantity of metal, we shall not
be at a loss for choice."