across the sliding doorway so that, even if they, or someone else, accidentally touched the hidden spring which sent the door to and fro, they would not be trapped.
"There, I guess that's all right," cried Sammy. "Now come on in!"
But Bob still hung back, though Sammy stepped across the door sill.
"Well, what's the matter now?" asked the discoverer of the hidden room.
"I'm thinking that the floor might give way," faltered Bob.
"Nonsense!" exclaimed Frank, taking sides with Sammy. "It must be solid, or how would it hold up the tables, chairs and the other things? I'm going in."
Bob would not be left behind, in the mysterious old house, so he followed his chums into the room. They advanced cautiously, and listened closely. There was no clicking sound, that might tell of hidden machinery.
"Pshaw! It's all right!" exclaimed Sammy, presently. "Now to see what those things are."
"Who do you s'pose put 'em there?" asked Frank, as they advanced toward the odd collection of things on the table.
"Counterfeiters!" exclaimed Sammy, promptly.
"Counterfeiters!" cried Frank. "What do you mean?"
"Just what I said," answered Sammy, with a calm smile, as though he knew it all. "This is a hidden place where some men have been making false coins, and maybe bad paper money too."
"You mean money that's no good?" asked Bob.
"Sure," replied Sammy. "Money that looks good, but which isn't—counterfeit money. I've read a lot about it. Fellows, we have discovered a counterfeiters' den!"
Sammy's chums looked rather frightened. It did seem as though they had stumbled upon some strange "den."
