Getting out their flashlights, they followed Fekmah through the crack and into a narrow tunnel. The air was damp and heavy from the breath of ages, but they trudged on through. After what seemed like hours, the passageway gradually became lighter, and the explorers found themselves in a large cave. Suddenly Joe stumbled and fell, unable to catch himself. "What's this!" he mumbled. Then, as his light was turned to the floor, he gave an exclamation of joy. "The hidden riches!" he said excitedly. "I've found them!" CHAPTER XXVIII Back to Civilization At Joe's welcome declaration, the others ran over in a high state of excitement. There, directly at their feet, was a huge chest of metal, the lid of which was pushed back. Piled up to the top were emeralds, diamonds, and a myriad of other precious stones. There were gold coins, rifles of ancient design, small silver boxes, and a hundred or more other valuable trinkets. For several minutes no one could speak. They were too amazed at the value of the treasure. Finally Dr. Kirshner looked up. "Thousands and thousands of dollars' worth," he muttered, as though he could hardly believe his eyes. "And it has all survived through the ages. In addition to the gold and precious gems, those rifles and coins will be of enormous value as relics." "Relics?" asked Joe. "Yes. They date back to the Middle Ages. You see," he went on, "the Tuaregs have always been fond of raiding caravans and cities. Whenever they see an opportunity to take possession of riches, they go out at once on a raid. The treasure in this cave was undoubtedly collected many hundreds of years ago. That is why there are guns and implements of the seventeenth century." "How interesting!" exclaimed Mr. Lewis. "I suppose now you are doubly glad we searched for this cave, because these relics will fit right in with your work as an archæologist." A thorough search of the cave was made, and the explorers discovered many other articles of great worth. "Now we'll carry this stuff out to the dromedaries," said Mr. Lewis. "It isn't wise to leave it in here too long." They had brought several large burlap bags, and the treasure was divided into these. There were eight of them, each filled to capacity. "Guess we'll have to make two trips," said Bob. "It'll be too much for us to get it all out at once." "We won't mind that," smiled Mr. Lewis. "The more there is the better." They carried out five of the sacks and then went back for the other three. When finally everything had been taken from the cave, they rested in the shade of the rocks. A lunch was prepared of canned food that had been taken from the supplies. All ate heartily, their eyes remaining much of the time on the bags of riches. "We may have to have more camels to get this stuff back to Wargla," remarked Mr. Holton. "I wonder if there is a chance of buying them from the Tuaregs?" "Probably is," Dr. Kirshner returned. "We'll see when we get these riches back to camp."