"It was invented by a General Waller, and is, I think, about twelve inches across at the muzzle. In spite of that comparatively small size, it fires a projectile weighing a thousand pounds, or half a ton, and takes five hundred pounds of powder. Its range, of course, no one knows yet, though I have heard it said that General Waller claims it will shoot twenty miles."
"Whew! Some shot!"
"I'm going to beat it," declared Tom, "and I want to do it without making such a monstrous gun that it will be difficult to cast it.
"You see, Ned, there is, theoretically, nothing to prevent the casting of a steel rifled cannon that would be fifty inches across at the muzzle, and making it a hundred feet long. I mean it could be done on paper—figured out and all that. But whether you would get a corresponding increase in power or range, and be able to throw a relatively larger projectile, is something no one knows, for there never has been such a gun made. Besides, the strain of the big charge of powder needed would be enormous. So I don't want merely to make a giant cannon. I want one that will do a giant's work, and still be somewhere in the middle-sized class."
"I see. Well, you'll probably get some points at Sandy Hook."
"I think so. We go day after tomorrow."
"Is Mr. Damon going?'
"I think not. If he does I'll have to get another pass, for mine only calls for two persons. I got it through a Captain Badger, a friend of mine, stationed at the Sandy Hook barracks. He doesn't have anything to do with the coast defense guns, but he got the pass to the proving grounds for me."
Tom and his chum talked for some time about the prospects for making a giant cannon, and then the young inventor, with Ned's aid, made some powder tests, using some of the explosive that had so nearly caught fire.
"It isn't just what I want," Tom decided, after he had put small quantities in little steel bombs, and exploded them, at a safe distance, and under a bank of earth, by means of an electric primer.