"H'm. Well, I've been figuring it out this way. There's a distinct current setting out of this big creek. You can see that by the way our boat hangs with her bow upstream. All right. Then it stands to reason that that piece of waste was thrown over at some point above. And then again, it looks as if the other craft might be a motor boat, for some one has been wiping the engine off. There was fresh oil on that waste. I could see it passing off on the surface of the water."
Jimmie fairly gasped in his great surprise.
"Did I iver hear the loike?" he said. "Next ye'll be tillin' me the kind of boat it is, I'm thinkin'. Looky here, Jack, ye don't guess now that it could be that same dhirty craft that was spoken of in the newspaper—the one as looked like the dear ould Tramp?"
"Oh! there would hardly be one chance in twenty of that happening," laughed the other. "Just think of both boats picking out this very creek, of the scores there may be south of St. Louis? Oh! that would be too funny for anything. It's just a plain motor boat, I reckon; and those aboard don't want to make our acquaintance any more than we do theirs. So there you are."
Jack pretended to dismiss the idea lightly; but nevertheless it remained with him during the balance of that evening, to give him more or less cause for speculation and anxiety.
At nine he bade Jimmie go to sleep, as he would sit up until eleven, when he promised to awaken the other. So the Irish lad, confident that no evil would befall them while Jack stood watch, curled up in his blanket, and presently his heavy breathing announced that he had found solace in slumber.
Promptly at eleven Jack aroused him, and handing over the gun, with positive directions that he was to be called if anything suspicious arose, he in turn took to his blanket on the bottom of the cockpit of the boat.
Why, it seemed that he had hardly lost his senses when he felt Jimmie shaking him. Just as before the Irish boy was whispering in his ear.
"Wake up, Jack; there's a boat comin' this way!" was what he heard.
"Why," replied the skipper, as he bounced up, "it sounds as if it might be coming in from the river! I can hear the stroke of oars, a lot of them, too."