The two passed out of his sight, and after a long time he heard the crack of Snowbird's pistol. He guessed that she had either shot at some wild creature, or else was merely at target practice,--rather a common proceeding for the two when they were on the hills together. Thus it is to be seen that Cranston knew their habits fairly well. And since he had kept a close watch upon them for several days, this was to be expected. He had no intention of being interrupted in this work he was about to do. He had planned it all very well. At first the intermittent snow-storms and the thaws between had delayed him. He needed a perfect snow crust for the long tramp over the ridge; and at last the bright days and the icy dawns had made it. The elder Lennox was still helpless. He had noticed that when Dan and Snowbird went out, they were usually gone from two to four hours; and that gave him plenty of time for his undertaking. The moment had come at last to make a thorough search of Lennox's house for those incriminating documents that Dan had found near the body of Landy Hildreth. The only really dangerous part of his undertaking was his approach. If by any chance Lennox were looking out of the window, he might be found waiting with a rifle across his arms. It would be quite like the old mountaineer to have his gun beside him, and to shoot it quick and exceptionally straight, without asking questions, at any stealing figure in the snow. Yet Cranston felt fairly sure that Lennox was still too helpless to raise a gun to a shooting position. He had observed that the mountaineer spent his time either on the fireplace divan or on his own bed. Neither of these places was available to the rear windows of the house. So, very wisely, he made his attack from the rear. He came stealing across the snow,--a musher of the first degree. Very silently and swiftly he slipped off his snowshoes at the door. The door itself was unlocked, just as he had supposed. In an instant more he was tiptoeing, a dark, silent figure, through the corridors of the house. He held his rifle ready in his hands. He peered into Lennox's bedroom first. The room was unoccupied. Then the floor of the corridor creaked beneath his step; and he knew nothing further was to be gained by waiting. If Lennox suspected his presence, he might be waiting with aimed rifle as he opened the door of the living room. He glided faster. He halted once more,--a moment at the living-room door to see if Lennox had been disturbed. He was lying still, however, so Cranston pushed through. Lennox glanced up from his magazine to find that unmistakable thing, the barrel of a rifle, pointed at his breast. Cranston was one of those rare marksmen who shoots with both eyes open,--and that meant that he kept his full visual powers to the last instant before the hammer fell. "I can't raise my arms," Lennox said simply. "One of 'em won't work at all--besides, against the doctor's orders."