Thor did not stop. He kept on. Where the rock wall bulged out the trail narrowed to five feet, and he had measured this fact as well as the distance. He caught the last dog, and drove it down under his paw. As it was torn to pieces the Airedale emitted piercing cries of agony that reached Bruce and Langdon as they hurried panting and wind-broken up the slide that led from the basin. Thor dropped on his belly in the narrowed trail, and as the pack broke loose with fresh voice he continued to tear at his victim until the rock was smeared with blood and hair and entrails. Then he rose to his feet and looked again for Muskwa. The cub was curled up in a shivering ball two feet in the crevice. It may be that Thor thought he had gone on up the mountain, for he lost no time now in retreating from the scene of battle. He had caught the wind again. Bruce and Langdon were sweating, and their smell came to him strongly. For ten minutes Thor paid no attention to the eight dogs yapping at his heels, except to pause now and then and swing his head about. As he continued in his retreat the Airedales became bolder, until finally one of them sprang ahead of the rest and buried his fangs in the grizzly's leg. This accomplished what barking had failed to do. With another roar Thor turned and pursued the pack headlong for fifty yards over the back-trail, and five precious minutes were lost before he continued upward toward the shoulder of the mountain. Had the wind been in another direction the pack would have triumphed, but each time that Langdon and Bruce gained ground the wind warned Thor by bringing to him the warm odour of their bodies. And the grizzly was careful to keep that wind from the right quarter. He could have gained the top of the mountain more easily and quickly by quartering the face of it on a back-trail, but this would have thrown the wind too far under him. As long as he held the wind he was safe, unless the hunters made an effort to checkmate his method of escape by detouring and cutting him off. It took him half an hour to reach the topmost ridge of rock, from which point he would have to break cover and reveal himself as he made the last two or three hundred yards up the shale side of the mountain to the backbone of the range. When Thor made this break he put on a sudden spurt of speed that left the dogs thirty or forty yards behind him. For two or three minutes he was clearly outlined on the face of the mountain, and during the last minute of those three he was splendidly profiled against a carpet of pure-white snow, without a shrub or a rock to conceal him from the eyes below. Bruce and Langdon saw him at five hundred yards, and began firing. Close over his head Thor heard the curious ripping wail of the first bullet, and an instant later came the crack of the rifle.