The hardest of riding was required to round them up and turn their faces toward the main herd, and it was not long before Avon found himself pitted against a steer fully as ugly as that which he had been obliged to shoot a few minutes before. All the others were finally forced into the right course, and this obstinate animal was disposed to join them, but after trotting for a short distance, he seemed to tire of being good, and, wheeling about, charged like a runaway engine at the youthful horseman who was harrying him so hard. In such crises a great deal depends on the intelligence of the horse. Thunderbolt sprang aside with the nimbleness of a monkey, and Avon received just enough warning to hold his place in the saddle. The steer attempted to keep up his pursuit, turning with remarkable quickness for such a large animal, but the dexterity of Thunderbolt was still greater, and he easily evaded the sharp horns which came near him more than once. Finally, as if he saw the uselessness of his pursuit, the steer headed in the opposite direction from that which he ought to have taken, and sped away with all the fleetness he possessed. Avon saw his uncle galloping to his help. "Leave him to me!" called the nephew; "I'll conquer him." Captain Shirril drew up, and, from his perch in the saddle, watched the result of the curious contest. Avon had his rope ready to fling over the horns of the fugitive, but before doing so, he resorted to another artifice, which few persons of his years can carry out successfully. It is not only difficult, but it is vastly more dangerous, in the event of the animal showing fight, as the steer had already done. It was necessary to force Thunderbolt close beside the fugitive, and, despite the courage of the mustang, it was only natural that he should feel some reluctance against doing this. Those horns possessed prodigious length and sharpness, and had already been turned upon him; but he was obedient, and urged by the pricking of the spur and the words of his master, he edged still nearer, though it need not be said that he kept an eye to windward. It was well he did so. Young Burnet was in the act of leaning forward to attempt the dangerous and difficult feat, when the steer again dropped his head, with one side lower than the other, as such animals do when assailing a foe sideways, and charged upon the mustang. Nine horses out of ten would have been fatally impaled by the suddenness of the assault, for there was no time for him to wheel; but with a dexterity that seemed incredible, he instantly rose on his hind feet and bounded clean over the steer. The wonder of the exploit was how the horse gathered himself and applied his strength with such astonishing quickness, but he did it like a trained gymnast, his rider maintaining his seat without difficulty and feeling a thrill of admiration at the amazing skill of his steed.