Bucks met the doctor and his party at the head of the canyon and took them to the high ledge across the river, where they had been brought by Glover in the morning. In the canyon it was already dark. Men were eating around campfires, and in the narrow strip of eastern sky between the walls the moon was rising. Work-trains with signal lanterns were moving above and below the break, dumping ballast behind the track layers. At a safe distance from the coming blast a dozen headlights from the roundhouse were being prepared, and the car-tinks from Sleepy Cat were rigging torches for the night. The blasting powder in twenty-pound cans was being passed from hand to hand to the chargers. Score after score of the compact cans of high explosive had been packed into the scattered holes, and as if alive to what was coming the chill air of the canyon took on the uneasiness of an atmosphere laden with electricity. Men of the operating department paced the bench impatiently, and trackmen working below in the flare of scattered torches looked up oftener from their shovels to where a chain of active figures moved on the face of the cliff. Word passed again and again that the charging was done, but the orders came steadily from the gloom on the ledge for more powder until the last pound the engineer called for had been buried beneath his feet in the sleeping rock. After a long delay a red light swung slowly to and fro on the ledge. From the extreme end of the canyon below the Cat's Paw came the crash of a track-torpedo, answered almost instantly by a second, above the break. It was the warning signal to get into the clear. There was a buzz of rapid movement among the laborers. In twos and threes and dozens, a ragged procession of lanterns and torches, they retreated, foremen urging the laggards, until only a single man at each end of the broken track kept within sight of the tiny red lantern on the ledge. Again it swung in a circle and again the torpedoes replied, this time all clear. The hush of a hundred voices, the silence of the bars and shovels and picks gave back to the chill canyon its loneliness, and the roar of the river rose undisturbed to the brooding night. On the ledge Glover was alone. The final detail he was taking into his own hands. The few that could still command the point saw the red light moving, and beside it a figure vaguely outlined making its way. When the red light paused, a spark could be seen, a sputtering blaze would run slowly from it, hesitate, flare and die. Another and another of the fuses were touched and passed. With quickening steps tier after tier was covered, until those looking saw the red light flung at last into the air. It circled high between the canyon walls in its flight and dropped like a rocket into the Rat. A muffled report from the lower tier was followed by a heavier and still a heavier one above. A creeping pang shot the heart of the granite, a dreadful awakening was upon it.