Gray nodded sleepily. The riddles presented no answer. He determined that he would learn the truth for himself. Wearied with his exertions, he was soon asleep. Silence held the camp, the brooding silence of great spaces, the threshold of infinity which opens before the wanderer in the Gobi. The wind stirred the sand into tiny spirals that leaped and danced, like dust wraiths across the gully, powdering the blankets of the sleeping men and the rough coats of the mules. Along the summit of the ridge a shadow passed across the stars. It hesitated to leeward of the embers of the fire, and the jackal crept on. The crescent moon moved slowly overhead, throwing a hazy half-light on the surface of the sand, and picking out the bleached bones of an antelope. Night had claimed the Mongolian steppe. CHAPTER X THE MEM-SAHIB SPEAKS It was nearly a week later, on the border of the Gobi, that Gray and Mirai Khan sighted the caravan. The day was rainy. During a space when the rain thinned, the Kirghiz pointed out a group of _yurts_ surrounded by camels and ponies a mile away. Gray scanned the encampment through his glasses, and made out that the caravan numbered a good many men, and that the _yurts_ were being put up for the night. The rain began again, and cut off his view. It was then late afternoon. Both men were tired. They had pushed ahead steadily from Liangchowfu, killing what they needed in the way of game, and occasionally buying goat's milk or dried fruit from a wayside shepherd. The few villages they met they avoided. Gray had not forgotten Wu Fang Chien, or the fears of Delabar. "They are Kirghiz _yurts_," said Mirai Khan when the American described what he had seen. "And it is a caravan on the march, or we would have seen sheep. Many tribes use our _yurts_. They are taken down and put up in the time it takes a man to smoke a pipe. But these people are not Kirghiz. My kinsmen have not wealth to own so many camels." "What do you think they are?" "Chinese merchants, Excellency, or perhaps Turkestan traders from Kashgar." Mirai Khan's respect for his companion had increased with the last few days. Gray's accurate shooting inspired his admiration, and the fortitude of the man surprised him. On his part, Gray trusted the Kirghiz. If Mirai Khan had meant to rob him, he had enjoyed plenty of chances to do so. But the Kirghiz's code would not permit him to steal from one who was sharing his bread and salt. "If they are Chinese," meditated the American, "it will not be wise to ride up to their camp. What say you, Mirai Khan?" The Kirghiz puffed tranquilly at his noisome pipe. "This. It is the hour of sunset prayer. When that is ended you and I will dismount, Excellency, and stalk the encampment. By the favor of God we will then learn if these people are Chinese or Turkomans. If the last, we shall sleep in a dry _aul_, which is well, for my bones like not the damp."