"I think it is Hank, coming back for his coat. I've been sleeping on it, and just discovered that there are papers in the pocket!"
"Oh, what can we do?" asked Jack, also in that low tone, inaudible five feet away.
"Get a match ready, Jack," said Paul, once more in his chum's ear; "and when I nudge you, light the lantern as fast as you can."
"All ready!" came back, a short time later.
Paul waited until he fancied that the unseen prowler must be groping in the dark very close to them. Then he thrust his elbow into Jack's side, causing him to grunt. But at the same instant a match flamed up, for Jack had been ready.
"Don't you dare move a foot!" called out Paul, instantly covering a crouching figure with the weapon he had in his hand.
Snap! Down went the lantern globe, and the cavern was brightly illuminated. It was Hank Clausin, just as Paul had suspected, and in his shirt sleeves too. He had come back for his coat, and walked into a trap.
The other three boys were now on their feet, and acting under Paul's directions they tied the man's hands. Poor Joe did not take any part in this ceremony. His heart was too sore, though he also rejoiced because Paul told him he had the precious papers on his person.
Hank pretended to be indignant at first, and claimed that he had done nothing wrong. Then he changed his tactics, and threatened the boys. Finding that this had no effect he turned to Joe, and pleaded with him. But Joe only shook his