Lurching this way and that, clinging for dear life, the boys and Mr. Hampton managed not only to retain their seats, but also to keep up with the others. On galloped the camels, every moment exhorted to further efforts. For a few minutes, while the sun still held, the trees of the oasis outlined against it seemed literally to hurl themselves forward, so rapid was the pace of the approaching party. Then the sun dropped out of sight, literally fell away, and was succeeded at once by darkness. Still the party kept on without abating its pace, the long legs of the camels eating up the miles at an unbelievably rapid rate. Jack, Bob and Frank had no time for thought. They were wracked in every limb. They felt as if they were being torn apart on a torture machine. Still they clung, while their camels surged forward with the rest. Then Ali’s voice was raised in a sharp command, and at once the other Arabs repeated certain cries to their camels which slowed them down. The boys had the good sense to realize what was wanted, and they, too, emitted the necessary grunts which seemed to constitute the language of camels. What was the explanation of this maneuvre? Simply that Ali saw looming ahead the shadowy outlines of the tall feathered palm trees constituting the little oasis, and had no desire to charge blindly without preparation or plan. Mr. Hampton urged his camel alongside that of Ali, and the boys also approached. Although twenty-five years older than his son, Mr. Hampton had an iron frame inured to fatigue through years of roughing it in the out-of-the-way places of the world. He was less blown as a result of the wild ride than the young fellows. Long since he had given up any idea of keeping the boys out of danger. All were strong and cool-headed in emergencies, and he had received plenty of evidence during recent years that they could take care of themselves. Rapidly he outlined what was to be done. Let all dismount, hobble the camels and leave them in charge of two of Ali’s men, and the balance of the party, consisting of Ali, four Arabs, the three boys and himself, nine in all, would advance afoot. In this way, the noise of their approach could be minimized. Besides, so far as four of their number were concerned, they would be better able to render a good account of themselves than if on camel back. Ali acquiesced, the necessary commands were given, and all caused their camels to kneel while they dismounted. Then two of the number were left adjusting hobbles and guarding the animals, while the others spread out a yard apart, and began to steal forward. CHAPTER III. THE MYSTERY AT THE OASIS.