"But we've found the boys now," contended Tommy. "We haven't got our hands on them yet, of course, but we know they're in there, and we know it's only a question of time when we get hold of them."
"Well," Will insisted, "I'm going to find a motive before I quit the case. I'm going to know who sent those boys here, and all about it, before I make any report to Mr. Horton."
"Go as far as you like," laughed Tommy. "My bump of curiosity is growing half an inch a day, and will continue to spread out until I find out exactly what those boys are doing burrowing in a deserted mine."
"Now, we'll get back to the point we started from," Will explained. "This boy who is undoubtedly doing duty outside the mine in the interests of the persons who sent the two boys in, furnishes the clue to the whole situation! When we find him, and find out what he's up to, and trace any communications he may make back to their original source, we'll have the whole case tied up tight!"
"That's right!" declared Tommy. "We'll have the case tied up tight if we succeed in getting hold of this third boy."
"Oh, go on!" laughed Sandy. "We'll be picking third boys and fourth boys and fifth boys out of the air the next thing you know. We never went away on a Boy Scout expedition yet that we didn't find all manner of kids hanging around on purpose to be discovered. We found them on Old Superior; and in the Everglades; and on the Great Continental Divide; and up in the Hudson Bay country, we began to think we had stumbled on the center of population so far as Boy Scouts were concerned!"
"There's just one thing that's likely to make us trouble," Will resumed. "And that is the fact that Canfield very foolishly slopped over to Ventner when explaining the purpose of our visit here. That bum detective knows now that we're here to search the mine. Of course he might have received, as Canfield says, most of his information from outside sources, but the caretaker should have thrown him off the track instead of telling him exactly what our mission here was."
"But Ventner came here to search for the boys himself!" George broke in. "At least, he says that he did."
"There's a mystery about the whole matter," Sandy declared, "and I'd like to help clear it up from beginning to end!"
"We're likely to have a chance!" laughed Tommy.