"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."