Clarence picked up a hard sun-baked clod, and, running forward, threw it at the coyote. It was a clever shot, and struck him on his slouching haunches. He snapped and gave a short snarling yelp, and vanished. Clarence returned with a victorious air to his companion. But she was gazing intently in the opposite direction, and for the first time he discovered that the coyote had been leading them half round a circle. “Kla'uns,” said Susy, with a hysterical little laugh. “Well?” “The wagon's gone.” Clarence started. It was true. Not only their wagon, but the whole train of oxen and teamsters had utterly disappeared, vanishing as completely as if they had been caught up in a whirlwind or engulfed in the earth! Even the low cloud of dust that usually marked their distant course by day was nowhere to be seen. The long level plain stretched before them to the setting sun, without a sign or trace of moving life or animation. That great blue crystal bowl, filled with dust and fire by day, with stars and darkness by night, which had always seemed to drop its rim round them everywhere and shut them in, seemed to them now to have been lifted to let the train pass out, and then closed down upon them forever. CHAPTER II Their first sensation was one of purely animal freedom. They looked at each other with sparkling eyes and long silent breaths. But this spontaneous outburst of savage nature soon passed. Susy's little hand presently reached forward and clutched Clarence's jacket. The boy understood it, and said quickly,-- “They ain't gone far, and they'll stop as soon as they find us gone.” They trotted on a little faster; the sun they had followed every day and the fresh wagon tracks being their unfailing guides; the keen, cool air of the plains, taking the place of that all-pervading dust and smell of the perspiring oxen, invigorating them with its breath. “We ain't skeered a bit, are we?” said Susy. “What's there to be afraid of?” said Clarence scornfully. He said this none the less strongly because he suddenly remembered that they had been often left alone in the wagon for hours without being looked after, and that their absence might not be noticed until the train stopped to encamp at dusk, two hours later. They were not running very fast, yet either they were more tired than they knew, or the air was thinner, for they both seemed to breathe quickly. Suddenly Clarence stopped. “There they are now.”