Shortly afterward the two boys went down to supper. The hotel had its usual number of guests, this being a favorite point for parties to start on the tour. "Don't look just now," said Frank, as they sat at a table; "but Abajo has taken his seat right back of you. And it wasn't accident, either, that made him do it; I believe he has been set to watch us!" From time to time, as they ate, Frank would report as to what the half-breed was doing; and while nothing occurred to actually prove the fact, still he saw no reason to change his mind. "And I'm going to find out if he's keeping an eye on us, so as to report to his employer, Eugene Warringford," Frank announced, as they were drawing near the end of the meal. "That sounds good to me," Bob remarked; "but how will you do it?" For answer Frank drew out a paper from an inner pocket. "You see this document," he observed, with a solemn look. "Well, it's only what you might call a dummy, being just an invitation I received a little while back to invest in some worthless mines over in the Hualpai Mountains of Mohave County. I kept it, meaning to figure out how these sharpers work their game. Now, when I hand you this, look deeply interested, as though it might be connected with the finding of Uncle Felix." "Oh! I see your move, and go you one better, Frank." For some little time they seemed to be conversing intently. Frank would occasionally tap the document, which he had sealed up in its envelope, as though he laid great stress on it. Finally he placed it on the table alongside his plate, and kept on talking. Shortly afterward the boys left the table in apparently such a hurry that they both forgot the envelope that lay there, half hidden by a napkin. Passing out of the room, they dodged back, and peered around the corner of the doorway. "There's the waiter at the table," said Bob. "Now he's found the fine tip you left there, and is putting it in his pocket, with a grin. If everybody treated him as well as that, he'd soon be owning one of these hotels himself, Frank." "Watch!" remarked his chum, in a low whisper. "Now he's discovered the document lying there where I left it. He takes it up. Perhaps he sees another dollar coming to him when he runs after us to return it." "But there's somebody at his elbow," Bob went on to say; "and it's Abajo, as sure as you live. He's saying something, and I reckon telling the waiter that you asked him to get the packet. There, he slips some money in the fellow's hand; and the waiter lets him take the envelope. And we'd better slip behind this coat rack here, for Abajo will be heading this way in a hurry." And hardly had they carried out that programme ere the half-breed glided past, one hand held in the pocket where he had thrust the "valuable" document! CHAPTER XIII GOING DOWN THE CANYON TRAIL "Was I right?" asked Frank, after the half-breed had disappeared.