There is something wonderfully exhilarating in night on the open desert. The boys felt it, so did Mr. Hampton. Who knows? Perhaps Ali and the Arabs were subject to this mysterious influence, too. Shortly, a little after seven as they knew from experience, the moon would be up, silvering the plain. All now, however, was in darkness except for the dim light of the stars. Yet it was a darkness filled with caressing breezes and the feeling of beauty. Despite the adventurous quest upon which they were embarked, despite the possibility, nay, the probability, that in a moment the night would be shattered with strife and death, each found himself yielding insensibly to this softening influence. Suddenly the howling of a dog broke the stillness. It was a long wailing cry that made the nerves quiver and caused each member of the party to grow tense. When does a dog howl like that? Ali and the Arabs knew. The rest, with their sensitive intelligences, guessed at the meaning. That howl meant mourning over a fallen master. As if it were a signal, other dogs joined in. A whole chorus of wailing notes effectively shattered the stillness of night. “Forward.” Mr. Hampton’s whisper ran along the ragged line. Again they advanced. Still not a sound from the oasis except the howls of dogs. The trees were closer now. Their leafy tops stood out stark against the sky. Abruptly as the seashore meets the land and ends, sand, the desert sand, met the thick grass of the oasis and ended. They were under the trees, in the grass, pushing forward. Suddenly the moon rose, and a new weird light fell over everything, bringing out the outlines of the trees, shedding a silver radiance between their tall trunks. Jack, who was in the middle of the advancing line, paused, startled. Some huge objects, black and indefinite in shape, seemed to rise out of the ground in front of him. What were they? He glanced hastily at the shadowy forms of his companions, whom he could discern among the trees right and left of him. Evidently, they, too, had seen, for they also had paused. The line moved forward, Ali and the Arabs taking the initiative. Jack advanced, too. If Ali felt no alarm, certainly he was not going to exhibit any. Bob and Frank experienced similar feelings. Then, in a moment, the nature of those strange objects became apparent. They were tents—great rambling horsehair tents of the Bedouins or desert Arabs. The howling of the dogs continued, at no great distance now, seeming to come from the other side of the tents which were a half dozen in number. Not a light was apparent. Not a human sound fell on their ears. A low command from Ali to his Arabs, from Mr. Hampton to the boys, drew in the scattered members of the line to a central group. They were at the rear of one of the Bedouin tents, the largest of all, probably that of the tribal sheik. So close were they that they could have put out their hands and touched it.