And there at the foot of the rocky trail he halted to watch and listen. The old memorable boom came to his ears. The flood was coming. For twenty-three years he had heard the vanguard boom of the Colorado in flood. But never like this, for in the sound he heard the strife and passion of his blood, and realized himself a human counterpart of that remorseless river. The moments passed and each one saw a swelling of the volume of sound. The sullen roar just below him was gradually lost in a distant roar. A steady wind now blew through the canyon. The great walls seemed to gape wider to prepare for the torrent. Bostil backed slowly up the trail as foot by foot the water rose. The floor of the amphitheater was now a lake of choppy, angry waves. The willows bent and seethed in the edge of the current. Beyond ran an uneven, bulging mass that resembled some gray, heavy moving monster. In the gloom Bostil could see how the river turned a corner of wall and slanted away from it toward the center, where it rose higher. Black objects that must have been driftwood appeared on this crest. They showed an instant, then flashed out of sight. The boom grew steadier, closer, louder, and the reverberations, like low detonations of thunder, were less noticeable because all sounds were being swallowed up. A harder breeze puffed into Bostil's face. It brought a tremendous thunder, as if all the colossal walls were falling in avalanche. Bostil knew the crest of the flood had turned the corner above and would soon reach him. He watched. He listened, but sound had ceased. His ears seemed ringing and they hurt. All his body felt cold, and he backed up and up, with dead feet. The shadows of the canyon lightened. A river-wide froth, like a curtain, moved down, spreading mushroom-wise before it, a rolling, heaving maelstrom. Bostil ran to escape the great wave that surged into the amphitheater, up and up the rocky trail. When he turned again he seemed to look down into hell. Murky depths, streaked by pale gleams, and black, sinister, changing forms yawned beneath them. He watched with fixed eyes until once more the feeling of filled ears left him and an awful thundering boom assured him of actualities. It was only the Colorado in flood. CHAPTER XII Bostil slept that night, but his sleep was troubled, and a strange, dreadful roar seemed to run through it, like a mournful wind over a dark desert. He was awakened early by a voice at his window. He listened. There came a rap on the wood. "Bostil! ... Bostil!" It was Holley's voice. Bostil rolled off the bed. He had slept without removing any apparel except his boots. "Wal, Hawk, what d'ye mean wakin' a man at this unholy hour?" growled Bostil. Holley's face appeared above the rude sill. It was pale and grave, with the hawk eyes like glass. "It ain't so awful early," he said. "Listen, boss."