"Didn't get as far today as we did yesterday," observed Bob, as the boys waited for Tishmak to find a suitable stopping place. The guide found the place he wanted between two large dunes, which were spread out over a large amount of ground. "Tishmak say we wait here and get supper," said Fekmah, after a moment of conversation in the native tongue. "Then when moon come out, we go on and try to make up for lost time." "That suits me," agreed Dr. Kirshner. "Almost anything would satisfy my appetite right now." The explorers dismounted and prepared the meal, which after the strenuous hours of constant traveling tasted delicious. Then they sat quietly in the semidarkness. At last the moon came out, and the desert was again seen to take on a new appearance. The sand was even more beautiful than the night before, white as it was from the soft light. Tishmak motioned for the adventurers to mount their dromedaries and get under way. If they expected to get over much more territory, it would be necessary to hurry. "Here's hoping we can come up to our hundred-mile minimum," said Joe, urging his camel to trot faster. It was nearly ten o'clock when they finally stopped for the night's slumber. Fekmah was well satisfied with the distance they had made that day. "Tomorrow we will come to Tudemait Plateau," he said, after conversing with Tishmak. "It is a rocky region, with large black boulders." "Then we won't see any more sand dunes?" asked Bob. "No. The country will be rather level, but we will have to go many kilometers out of way to avoid rocks." "That'll suit me," put in Joe. "I'm tired of seeing nothing but sand." That night they trusted to good fortune and did not set a guard. Tishmak informed them that there was little danger of robbers in that region, and the alertness of the camels would be an added precaution. "We are nearing the country of the Tuaregs," explained Fekmah. "These natives are friendly, but drive away nomad robbers. We probably be safe tonight." And they were. The next morning they had completely regained their natural liveliness and pep, feeling thoroughly refreshed and ready for anything the day might bring. Breakfast over, the long journey was resumed. As Tishmak had predicted, the country gradually began to change. The sand dunes that had recently been high slowly became smaller and lower, and vegetation increased still more. Small rocks were everywhere, their color a dark gray or black. In the distance the sharp crags of the Tudemait Plateau could be seen. As the explorers neared a low long mound, Tishmak's dromedary suddenly halted and sniffed nervously. A moment later the animals of the other explorers also came to a stop. "What's this!" exclaimed Mr. Lewis, looking about wonderingly. "Guess they heard something," said Dr. Kirshner. "What it was, we'll see in a moment. They have an uncanny power of detecting noises that we men can't catch."