"For two reasons. I don't want a sick man on my hands. And--you tried to destroy the maps. There's another reason----" Gray hesitated, and broke off. "I don't claim to be your judge. Every man follows his own course in life. But yours and mine don't fit any longer. It's good-by, Professor." He rose, knocking the ashes from his pipe. Delabar gave an exclamation of alarm. "Suppose the men of Wu Fang Chien find me?" "You'll be safer than here with me." Delabar stared into the steady eyes of his companion, and his gaze shifted. "I can't go back. I must go with you." "I've said good-by. Your coolie knows what he's to do. Choose your two mules." "No. I'll be better now----" Gray smiled slightly. "I doubt it. I've been watching you. Closer than you thought. Which mules do you want?" Delabar flushed, and turned his animal back to the waiting group. He was muttering to himself uncertainly. Gray walked beside him. Once he spoke. "Buddhism, Professor, is a bad thing to think about. As Wu Fang Chien said, it is bad to enter forbidden ground. Well, good luck, Delabar. It's better to part now--than later----" But Delabar passed out of hearing. He did not look again at Gray, who remained talking to the Kirghiz. Later, Gray regretted that he had not watched Delabar. The Syrian wasted no time in selecting two animals, and turned back at once. Mirai Khan followed the cavalcade with puckered brows as they passed out of sight among the hillocks. Gray waved his hand once when he thought Delabar looked back. But the man did not turn, humping himself forward over his beast, his head between his shoulders. "It is a pity," said Mirai Khan, stroking his gray beard reflectively, "to lose the two mules, and so much money. However, what will be, will be. Come, I know a davan nearby where we can rest until we are ready to go forward, at night." He conducted Gray along a sheep track for some miles to a ravine well into the hillocks. Here there was a grove of cedars, and a small spring. While Gray built a fire, Mirai Khan, acting on the white man's instructions, unburdened the two remaining mules. "We have little food, Excellency," he observed suggestively. "Open one of the boxes," said Gray. Presently Mirai Khan appeared beside the fire, carrying a heavy object. "What manner of food is this?" he asked contemptuously. "I have tasted and the flavor is a mingling of salt and sour wine." Gray stared at the object in surprise. It was one of the boxes, with the cover removed. It was filled with an array of long bottles. One of these had the cork removed, and effused an acrid odor. Gray picked it up. It was a bottle of a very good kind of vinegar. Hastily Gray went to the other boxes and opened them, after noting that the fastenings and the seal were intact. They were all filled with vinegar.