muzzle of the gun, though sometimes the big breech block will be
shattered.

With eager eyes Tom and Ned watched the preparations for firing
the big gun. The charge of powder was hoisted out of the bomb-
proof chamber below the barbette, and then the great projectile
was brought up in slings. At the sight of that Tom realized that
the gun was no ordinary one, for the great piece of steel was
nearly three feet long, and must have weighed nearly a thousand
pounds. Truly, much powder would be needed to send that on its
way.

"I'm afraid, General, that you are using too much of that
strong powder," Tom heard one officer say to the inventor of the
gun. "It may burst the breech."

"Nonsense, Colonel Washburn. I tell you it is impossible to
burst my gun--impossible, sir! I have allowed for every
emergency, and calculated every strain. I have a margin of safety
equal to fifty per cent."

"Very well, I hope it proves a success."

"Of course it will. It is impossible to burst my gun! Now, are
we ready for the test."

The gun was rather crude in form, not having received its final
polish, and it was mounted on a temporary carriage. But even with
that Tom could see that it was a wonderful weapon, though he
thought he would have put on another jacket toward the muzzle, to