Grosvenor's blanket had not been taken from him when he was a prisoner, and it was still strapped on his back. He and Robert found the rest most welcome and they were not slow in wrapping the blankets around their bodies and making themselves comfortable. Without willing it, they fell asleep, but were awakened shortly after dawn. "See!" said Willet, pointing toward the south. A filmy trail of blue smoke rose across the clear, blue sky. "That, whatever it is," said the hunter, "is what St. Luc is advancing against, but in spite of all the risks we've run we'll be there in time to give warning." Robert looked with the deepest interest at the smoke, which was a long way off, but it seemed to rise from the lake's edge and he thought it must be a British or American post. It was at a most exposed and dangerous point, but his heart thrilled at Willet's words. Yes, in spite of every danger that had been thrown across their path, they would be able to carry word in time. "We'll be there in half an hour, and we'll know what's going forward," said Willet. "We'll know before then," said Grosvenor confidently. "Our marvelous Indian friend here will tell us when we're half way." Tayoga smiled, but said nothing, and they started again, Willet, as usual, leading, and the Onondaga bringing up the rear. The spire of smoke thickened and darkened, and, to Robert and Grosvenor, it seemed most friendly and alluring. It appeared to rise from a little point of land thrust into the lake but they could not yet see its base, owing to an intervening hill. Just before they reached the crest of the hill Tayoga said: "Wait a moment, Great Bear. I think I hear a sound from the place where the smoke rises, and we may be able to tell what it means." They stopped promptly, and the Onondaga put his ear to the earth. "I hear the sounds very distinctly now," he said. "They are of a kind not often occurring on these shores." "What are they?" asked Robert eagerly. "They are made by axes biting into wood. Many men are cutting down trees." "They're building a fort, and they're in a hurry about it or they would not be felling trees so early in the morning." "Your reasoning about the hurry is good, Dagaeoga. The white man will not go into the forest with his ax at daybreak, unless the need of haste is great, but it is not a fort they build. Mingled with the fall of the axes I hear another note. It is a humming and a buzzing. It is heard in these forests much less often than the thud of the ax. Ah! I was in doubt at first, but I know it now! It is the sound made by a great saw as it eats into the wood." "A saw mill, Tayoga!" "Yes, Dagaeoga, that is what it is, and now mind will tell us why it is here. The logs that the axes cut down are sawed in the mill. The saw would not be needed if the logs were to be used for building a fort. The ax would do it all. The logs are being turned into planks and boards."