"Why, it's as plain as print," declared the government agent. "This warning letter was dropped from an airship, Tom."
"From an airship?"
"Yes. They sailed right over this place, and let the letter fall, with this lead weight attached, to bring it to earth just where they wanted it to fall."
"Bless my postage stamp!" cried Mr. Damon. "I never heard of such a thing."
"I see it now!" exclaimed Tom. "While we were off over the river, watching for the smugglers, they were turning a trick here, and giving us a warning into the bargain. We should have stayed around here. I wonder if it was Andy's airship that was used?"
"We can easily find that out," said Mr. Whitford. "I have a detective stationed in a house not far from where the Foger's live. Andy came back from Shopton yesterday, just before you arrived here, and I can soon let you know whether he was out last night. I'll take this letter with me, and get right up to my office, though I'm afraid this won't be much of a clew after all. Print isn't like handwriting for evidence."
"And to think they sailed right over this place, and we weren't home," mourned Tom. "It makes me mad!"
