“Jove!” cried Tom. “That was a narrow escape! In another second I’d have been in plain view, and then the game would have been up.” Hastily he stooped down again, and waited until the old man had gone down the hill, and was out of sight. Fortunately he took a course that would not bring him near the other hidden lads. “Now to see if the coast is clear,” remarked Tom, after waiting a bit to make sure that the hermit was not coming back. “If Skeel and those fellows are in there I won’t mind them so much. I rather guess they won’t be glad to see me.” Exercising all needful caution, Tom advanced closer to the ancient structure. He gained the old driveway, unseen, he hoped, and, walking carefully about, he listened intently. There was no sound save the murmur of the water in the old sluiceway. “We’ll take a chance,” decided the lad, and he hurried back to signal his chums. In a few seconds they joined him. “Now, fellows, we’ve got to work quickly,” explained Tom. “There’s no telling when Wallace will be back, though I think he’s gone for a long tramp. Skeel and the others don’t seem to be here.” “What’s your plan?” asked Jack. “To compare the mill, as it actually is, with the copy of the drawing we have. I want to see if we can find a secret hiding place anywhere, or some means of getting to the third floor. I don’t believe that scheme of tossing up a rope, and climbing it, would be safe, for it might slip, or the wood might be so rotten that it would pull away. But I think we ought to be able to get to the third story some other way.” “So do I,” agreed Jack. “Well, let’s start in, and see where we come out. We’ll begin at the basement.” This they did, and it did not take them long to make certain that the plan of the lower floor, as it was shown on the piece of paper Tom had found, was substantially correct. “There doesn’t seem to be any place for a secret compartment for the hiding of treasure down here,” remarked Dick, when they had finished their inspection. “That’s right,” agreed Tom, who had been looking at the thickness of the walls. “They are solid enough, and unless we tore them down we couldn’t come at anything hidden in them. Let’s go upstairs.” The examination there took longer, for, not only were they anxious to see if it was possible to secrete treasure there, but they wanted to find how the old man got to the third story, since there was no evidence that he lived in any other part of the mill. But here, too, they were doomed to disappointment. They found that the plan they possessed corresponded with the actual building in every particular. “And yet I’m sure there is some secret stairway or passage,” insisted Tom. “Let’s try the walls and see if they sound hollow.” They were about to start this when Jack exclaimed: “Say, what about that sentinel we were going to post? I thought someone was going to be on the watch to give warning if anyone approached.”