Gray had left the useless boxes of vinegar behind. And as he went he puzzled over the riddle of Arminius Delabar. It was a riddle. Van Schaick and Balch had said little about the man, for they had been in a hurry to get Gray started on his voyage. He remembered they said Delabar was a Syrian or Persian by birth, an inveterate traveler who had been in most of the corners of the earth, and--the only man in America who could speak Chinese, Turki, Persian and Russian, the four languages a knowledge of which might be necessary on their expedition, and who thoroughly understood anthropology, with the history of Central Asia. This being the case, Gray had taken a good deal on himself when he sent Delabar back. But he had done right. The vinegar boxes proved it. Gray had a steady, logical mind which arrived at decisions slowly, but usually accurately. He now reasoned out several things. Delabar, he guessed, had not come willingly on the expedition. Even on the steamer he had shown fear of the Gobi. Why? He must have known something about the desert that he did not tell Gray. What was that? Gray did not know. This led to another question. Why, if the man was afraid, had he come at all? He might have refused to start. Instead he had bought, purposely, a shipment of worthless stores; he had worked on Gray's mind to the best of his ability. Gray suspected that Delabar had come because he wanted to prevent him--Gray--from reaching the Gobi. But Delabar might have stated his objections before they left San Francisco. Why had he not done so? Possibly because, so reasoned Gray, Delabar had thought if he prevented Gray from starting on the mission, Van Schaick and Balch would engage another man. Gray checked up the extent of his reasoning so far. He had decided that Delabar had been bent on preventing not him but any American from undertaking the trip to the Gobi. And to do that the Syrian had come along himself, although he was afraid. Yes, Delabar had certainly been afraid. Of what? Of Wu Fang Chien for one thing; also the Buddhists. He had been on the verge of a breakdown at the inn at Liangchowfu after their experience in the temple. Gray recalled a number of things he had passed over at the time: Delabar's pretext of purchasing supplies at Shanghai. The scientist had been absent from him for many hours, but had bought nothing. Then the incident of the Chinese steward on the river steamer of the Yang-tze. Something had been thrown overboard which a passing junk had picked up. Had this something been information about Gray's route? It was more than possible. And the attack at Honanfu. How had the Chinese known that Gray kept a rifle under his bed--unless Delabar had so informed them? Delabar had been frightened at the attack. Perhaps, because it failed.