"Ned, what do you think? I know who had my airship!"
"How?" asked Ned, in wonder.
"By that button clew! Yes, it's the same kind--they're as alike as twins!" and Tom brought out the button which he had put away in his desk. "See, Boylan had one just like this on the back of his coat. The other was missing. Here it is--it was in the seat of my airship, where it was probably pulled off as he moved about. Ned, I think I've got the right clew at last."
Ned said nothing for several seconds. Then he remarked slowly:
"Well, Tom, it proves one thing; but not the other."
"What do you mean?"
"I mean that it may be perfectly true that the button came off Mr. Boylan's coat, but that doesn't prove that he wore it. You can be reasonably sure that the coat was having a ride in your Eagle, but was Boylan in the coat? That's the question."
"In the coat? Of course he was in it!" cried Tom.
"You can't be sure. Someone may have borrowed his coat to take a midnight ride in the airship."
"Mr. Boylan doesn't look to be the kind of a man who would lend his clothes," remarked Tom.