sides having the satisfaction of helping my country."

"Good for you, Tom! I wish it was time to go to Sandy Hook now. I'm
anxious to see that big gun. Do you know anything about it?"

"Not very much. I have heard that it is not quite as large as the old
sixteen-inch rifle that they had to throw away because of some trouble,
I don't know just what. It was impractical, in spite of its size and
great range. But this new gun they are going to test is considerably
smaller, I understand.

"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