What Tom Swift held in his hand looked like a small cannon
ball, but it could not have been solid or the young aviator would
not so easily have held it out at arm's length for his friend Ned
Newton to look at.

"This puts a different face on it, Ned," Tom went on, as he
turned the object over.

"Is that likely to go off?" the bank clerk asked, as he came to
a halt a little distance from his friend.

"Go off? No, it's done all the damage it could, I guess."

"Damage? It looks to me as though it had suffered the most
damage itself. What is it, one of your models? Looks like a bomb
to me."

"And that's what it is, Ned."

"Not one of those you're going to use on your aerial warship,
is it, Tom?"

"Not exactly. I never saw this before, but it's what started
the fire in the red shed all right; I'm sure of that."

"Do you really mean it?" cried Ned.

"I sure do."