"I can do nothing else!" he exclaimed. "'Tis a poor return for the services you have done me, and I tender my apologies for the action I'm about to take. But guard yourself, St. Luc!" "And you, Lennox, look well to yourself when Braddock marches! Every twig and leaf will spout danger!" His light manner was wholly gone for the moment, and his words were full of menace. Up the street, a sentinel walked back and forth, and Robert could hear the faint fall of his feet on the sand. "Once more I bid you beware, St. Luc!" he exclaimed, and raising his voice he shouted: "A spy! A spy!" He heard the sentinel drop the butt of his musket heavily against the earth, utter an exclamation and then run toward them. His shout had also been heard at the tavern, and the guests, bareheaded, began to pour out, and look about confusedly to see whence the alarm had come. Robert looked at the sentinel who was approaching rapidly, and then he turned to see what St Luc would do. But the Frenchman was gone. Near them was a mass of shrubbery and he believed that he had flitted into it, as silently as the passing of a shadow. But the sentinel had caught a glimpse of the dusky figure, and he cried: "Who was he? What is it?" "A spy!" replied Robert hastily. "A Frenchman whom I have seen in Canada! I think he sprang into those bushes and flowers!" The sentinel and Robert rushed into the shrubbery but nothing was there. As they looked about in the dusk, Robert heard a refrain, distant, faint and taunting: "Hier sur le pont d'Avignon J'ai oui chanter la belle Lon, la." It was only for an instant, then it died like a summer echo, and he knew that St. Luc was gone. An immense weight rolled from him. He had done what he should have done, but the result that he feared had not followed. "I can find nothing, sir," said the sentinel, who recognized in Robert one of superior rank. "Nor I, but you saw the figure, did you not?" "I did, sir. 'Twas more like a shadow, but 'twas a man, I'll swear." Robert was glad to have the sentinel's testimony, because in another moment the revelers were upon him, making sport of him for his false alarm, and asserting that not his eyes but the punch he had drunk had seen a French spy. "I scarce tasted the punch," said Robert, "and the soldier here is witness that I spoke true." A farther and longer search was organized, but the Frenchman had vanished into the thinnest of thin air. As Robert walked with Willet and Tayoga back to the tavern, the hunter said: "I suppose it was St. Luc?" "Yes, but why did you think it was he?" "Because it was just the sort of deed he would do. Did you speak with him?" "Yes, and I told him I must give the alarm. He disappeared with amazing speed and silence."