"Yes, and if the old plank could talk it'd be easy for us to get at the truth. But then of course that isn't possible," Jerry remarked, with a sigh.
"Help me to put the plank back in place again," said Frank, and after this had been done he commenced to work at it as if to see whether one person could manage to raise the heavy board.
"It can be done, you see," was what Frank said, as, managing to get his fingers underneath, he raised the plank a little.
"Now what's the line you're figuring on, Frank?" demanded Jerry; "because it's as plain to me as the nose on my face that you've struck a strong clue."
"Yes, tell us what it is, won't you, Frank?" urged Will.
"Well, listen," the other began to say, slowly, as with upraised finger he marked off each point in his theory. "Look back a little, Will, to when we got home here after our high jinks up in the woods. Don't you remember what we discovered the first thing?"
Will thereupon uttered an exclamation, while his face lighted up with eagerness.
"That's so, Frank!" he exclaimed; "we knew somebody had been in here after we started out the afternoon before. The door wasn't shut close, and a chair lay on its side on the floor. Besides that, a number of little things showed they had been disturbed. Yes, somebody had been in the cabin!"
Jerry gave a shrill cry in which delight could be traced.
"It was that person, then, who hid the pesky old cup under the loose plank; that goes without saying, Frank!" he announced, as though his mind was made up to that fact and could not be easily changed.