“I guess it’s safe enough now,” spoke Jack, after a bit, from his position on a cushioned seat in the stern, his stiff leg stretched out in front of him. “Turn on the gas, Tom, and start her off.” This was done, and soon the _Tag_ was making good time down the river toward the lake. “What about the feed?” asked Bert. “Seems to me we’ve earned it now, Tom.” “Let’s look at that paper first,” suggested Jack. “That’s more important than feeding our faces.” “Here it is,” spoke Tom, producing it from his pocket, while Dick took the wheel. Eagerly the others looked over the shoulder of our hero as he unfolded the paper. It proved to be quite large, being of thin but tough fabric, and it was creased into many folds, as though it had been intended to occupy a small space. It was covered with lines, words and figures. “An architect’s plan! Nothing but a plan!” exclaimed Jack. “That’s all,” added Bert in disappointed tones. “Maybe they didn’t drop it at all,” suggested Dick. “It may have been there all the while, and they didn’t bother to pick it up. I don’t see what good it is, though.” Tom said nothing for a space. He was intently studying the sketch. “Chuck it overboard,” spoke Dick. “No, mail it back to Skeel, and tell him how we found it,” was Bert’s suggestion. “It’ll show him how close we are on his trail.” “I’ll do neither,” answered Tom quietly. “We’re going to keep this piece of paper for ourselves.” “Can you make head or tail of it?” asked Jack. “I fancy I can,” answered our hero. “I think this is a detail drawing of the floor plans of the old mill, and I believe it may be the key to the location of the treasure--or at least the place where the treasure is supposed to be.” “You do?” cried his chums in a chorus. “I sure do,” replied Tom, with conviction. “And I’m sure either Skeel, or the hermit, dropped this. It wasn’t there on the path before they held their confab, and neither Sam nor Nick was near the spot where the paper lay. Boys, I believe we’ve got a valuable clue here!” “Let’s see it,” requested Jack, and Tom passed it over. His chum gazed at it thoughtfully, turned it around, and peered at it upside down. Then he remarked, as he passed it back: “Well, if you can make anything out of that, Tom, you’re a good one. What does it say?” “That I don’t know yet,” spoke our hero. “It’s going to take some studying to ferret this thing out, but we’ll do it. Meanwhile we’ll just forget all about it for a little while, and have some grub. Get busy, fellows, and have dinner.” They ate with exceedingly good appetites, while the motorboat speeded on her way toward the lake. Between bites they talked of their experience, and kept a lookout for any possible signs of their former professor, his cronies and the hermit.