When the boys returned to the shore the motor-boat had disappeared from sight. This strange disappearance, however, was not so confusing to the boys as the discovery they speedily made concerning the skiff which they themselves had left on the shore of the cove. CHAPTER XV A SIGNAL OF DISTRESS "Where did that sail come from?" demanded John, as he stopped abruptly and looked in astonishment at the little skiff. Thrown carelessly across it was a sail and small mast. "Where did they come from?" he repeated. "I didn't put them there," replied Fred. "Who did then?" "I don't know any more about it than you do." "Well, somebody has been good to us and tried to help us get away from this deserted island. What did that man say the name of it is?" "Western Duck Island. There are a half-dozen of these islands, I remember now." "I shan't feel very badly if I never see nor hear of them again." "We're all right now. We have a sail." "Perhaps we are, though I haven't forgotten that that little Jap said we are forty miles from Mackinac." "What is forty miles to fellows who have got a boat and a sail?" While the two boys were talking they had adjusted the mast and rigged the little leg-of-mutton sail. It was plain to both boys that if conditions continued favorable they had found an easier way by which they could return to their hotel than by trying to row. "Come on," called Fred cheerily, his courage now having returned in full measure. "Come on. Don't let's stay here any longer than we have to." "I'm with you," responded John. "Now who's going to sail this boat first?" "You are, by unanimous consent; I think it will be safer for the crew to have you sitting in the stern than it will be to have you crawling around the bow." The mystery of the sail had not been explained, but whoever had left it plainly had intended that it should be used. The wind was light but the little skiff drew rapidly away from the shore of Western Duck Island, and as he glanced behind him Fred said, "I feel almost as Columbus must have felt when he set forth in his three tubs to find a new world." "I never knew that Columbus sailed in three boats before," laughed John. "I didn't mean that Columbus himself sailed in three boats, at least at the same time. I used his name as the name of his whole party. I forgot for the minute what kind of material I was dealing with." "Never you mind that," retorted John. "You just watch me while I sail this boat. I'm going to head her up the shore toward Drummond Island. If we can make that I think we'll be all right for the rest of the way." "And if we don't make it what are you going to do?" said Fred more seriously. "It'll be time enough for me to explain to you, my friend, when the occasion arrives. Meanwhile just see how smoothly we are speeding on our way."