"What! You've been there?" "No, but we've seen the cave in which it is. In fact, it is possible to see it from here." Mr. Holton took out his binoculars and handed them to his son. "Look away over there," the naturalist said, pointing to a distant wall of rock that was many hundred feet high. "That small shelf on the side of the cliff is an opening into the cave in which are the hidden riches." Bob scanned the landscape ahead. Then he cried out in surprise and amazement. "A cave away up in that cliff? Seems impossible. How can you get to it?" "Must be an entrance on the other side," Dr. Kirshner replied. "Fekmah's map no doubt points it out. Whether he remembered to put it on the duplicate after the original was stolen, we have yet to see. Where is he now?" "Who, Fekmah? I left him at camp this morning." "Let's go there now." First, however, Dr. Kirshner engaged in conversation with the Tuaregs in their own language. He told them, among other things, of how grateful he and the other former prisoners were for their help in releasing them from the clutches of the Arabs. The natives were very courteous and friendly, inviting the archæologist to their village. He returned that he would be delighted to visit them, and concluded by saying that they would be given a reward for their generous services. "Now let's get out of here," he said, turning to his friends. "I'm particularly anxious to get back to camp and see Fekmah. I wonder if any misfortune could have come upon him and our camels." The Americans, Tuaregs, and Arab captives left the cave behind and trudged down the mountainside. But before they did so, they carried out the food supply that had been in the cave for the prisoners and their guards. It consisted of simple native food, but was welcomed by the Americans and Tishmak. "There is much more in the cave where the hidden treasure is," remarked Joe, as he walked beside his chum, who was leading his camel. "We won't need to worry about not having enough to eat for many weeks." "Doubt if we'll stay here that much longer," Bob said. "But I imagine it'll come in handy all right." The Arabs were ordered to walk in front of the Americans and Tishmak. The Tuaregs rode on to their village, after asking their newly made friends to visit them the next morning. It required several hours for the explorers and their captives to get back to camp, going on foot as they did. But when they finally came within sight of the tent and camels, all gave sighs of relief. Fekmah came running out to meet them, his face showing an intense thankfulness at again seeing his American friends and Tishmak alive and apparently none the worse for their experience. "So Bob got you from Arab demons," he muttered and then added: "I knew he would do it." Nothing would satisfy him but a complete detailed account of their experiences, and it was Mr. Lewis who related all of the happenings since they had last left camp.