creaking among the timbers reaching down into

  Relief came from a second shot from beside the trestle. And after it a cry as before, and a volley of wild firing. The Indian was wasting no shots; his night eyes were exacting toll.   Mahon decided to investigate. Also he wished to meet the Indian--to hear his voice--to touch him. Leaving Williams in charge, with definite instructions as to Torrance and Murphy, he crept from the back door to the edge of the trestle. The Indian was not there. Mahon wondered how much of it was dream. Then the redskin was swept from his mind by the sound of life far below about the base of the trestle. The bohunks were attacking there.   He became aware of a strange creaking among the timbers reaching down into the blind depths. Suddenly a spurt of flame from their midst darted to the valley below. Mahon felt himself shiver at the death-shriek that replied. The Indian, somewhere far below his eye, was shooting now to kill. A dash of hasty feet told of momentarily defeated plans. A storm of bullets rattled from the trees among the timbers and whistled above Mahon's head as he lay under cover of the grade. Then a new peril startled him. Three rifles cracked in rapid succession from behind the stable.   For a moment Mahon thought of stalking them, but reflection decided him against it. It was a risk too great to justify exposing his life. For all it would gain at the best he, in charge of the defence, must not undertake it. And there was really no extra danger to the shack, since it could not be taken from the rear.   He wormed his way back more carefully through the kitchen door and reported what he had seen. Torrance, far from feeling gratitude for the Indian's defence of the trestle, fumed that it should be left to the care of any one but himself. In the midst of his grumbling the first bullets struck the shack. They penetrated door and window and embedded themselves in the rear walls. But Mahon had disposed of the defenders with that peril in mind.