“What’s the matter; can’t you fellows sleep?” asked Ned, at length.

“No; can you?” inquired Bart.

“Nope. Let’s talk.”

“All right. Say, what do you suppose that man was doing around the mud volcano?” ventured Frank.

They had discussed this, in all its bearings, several times that afternoon, but it was a subject full of new possibilities, and they eagerly welcomed another chance to talk about it.

“I think he was after mud turtles,” said Bart.

“Say,” asked Fenn, suddenly, “did it ever strike you fellows that this fellow might be a detective?”

“A detective?” gasped the other three.

“Yes; after us,” went on Stumpy. “You know we’re suspected of taking that bracelet. It hasn’t been found, and what would be more natural than for Professor Long to hire a private detective, and have him shadow us. I didn’t think of that until just now, but I’ll wager I’m right. You’ll find that man is a detective, and he’s watching us; trying to get a trace of the bracelet. Maybe he thinks we have it, and are going to hide it off in the woods here.”

“Say!” cried Bart, “that’s not a bad ‘think’ of yours, Stumpy. I wouldn’t be surprised but what you are right,” and then they fell to discussing that aspect of the case. It was quite a reversal of the former situation. Instead of them being after the mysterious man, he might be after the chums.