see, Tom, he admits that he was jealous of you. Now what is there to prevent him from hiring someone to dope your powder, and then, to divert suspicion from himself, faking up a letter and inviting himself to the blowout."
"But if he did that—which I don't believe—why would he come when there was danger, in case his trick worked, of the whole place being blown to kingdom come?"
"Ah, but you notice he didn't arrive until after danger of an explosion had passed," commented Ned.
"Oh, pshaw!" cried Tom. "I don't take any stock in that theory."
"Well, maybe not," replied Ned. "But it's worth thinking about. I believe if General Waller could prevent you from inventing your big gun, he would."
The days that followed were busy ones for Tom. He worked on the powder problem from morning to night, scoring many failures and only a few successes. But he did not give up, and in the meanwhile drew tentative plans for the big gun.
One evening, after a hard day's work, he went to the library where his father was reading.
"Tom," said Mr. Swift, "do you remember
