When the black horse had spent his strength in a vain attempt to rid himself of the dreadful burden that had attached itself so securely to his back, he was herded back to the corral, where the burden set him free. Dripping with sweat, trembling in every limb and muscle, wild-eyed, with distended nostrils and heaving flanks, the black crowded in among his mates again, his first lesson over--his years of ease and freedom past forever. "And which will it be this time?" came Curly's question. "I'll have that buckskin this trip," answered Phil. And again that swirling cloud of dust raised by those thundering hoofs drifted over the stockade enclosure, and out of the mad confusion the buckskin dashed wildly through the gate to be initiated into his new life. And so, hour after hour, the work went on, as horse after horse at Phil's word was cut out of the band and ridden; and every horse, according to disposition and temper and strength, was different. While his helpers did their part the rider caught a few moments rest. Always he was good natured, soft spoken and gentle. When a frightened animal, not understanding, tried to kill him, he accepted it as evidence of a commendable spirit, and, with that sunny, boyish smile, informed his pupil kindly that he was a good horse and must not make a fool of himself. In so many ways, as the Dean had said at breakfast that morning, horses are just like men. It was mid-afternoon when the master of the Cross-Triangle again strolled leisurely out to the corrals. Phil and his helpers, including Little Billy, were just disappearing over the rise of ground beyond the gate on the farther side of the enclosure as the Dean reached the gate that opens toward the barn and house. He went on through the corral, and slowly, as one having nothing else to do, climbed the little knoll from which he could watch the riders in the distance. When the horsemen had disappeared among the scattered cedars on the ridge, a mile or so to the west, the Dean still stood looking in that direction. But the owner of the Cross-Triangle was not watching for the return of his men. He was not even thinking of them. He was looking beyond the cedar ridge to where, several miles away, a long, mesa-topped mountain showed black against the blue of the more distant hills. The edge of this high table-land broke abruptly in a long series of vertical cliffs, the formation known to Arizonians as rim rocks. The deep shadows of the towering black wall of cliffs and the gloom of the pines and cedars that hid the foot of the mountain gave the place a sinister and threatening appearance.