"And you're not the only one," said Dr. Kirshner, shaking his head. "But the desert swarms with bandits, and it will be strange if we don't have another such encounter." "Maybe we won't have such good luck the next time," mused Joe. "Nonsense!" Bob retorted. "We'll drive them off the same as we did these men." "But you got that wrong," corrected Mr. Holton, smiling. "They made _us_ get away." Bob looked a little sheepish as he saw where he had been caught. "Well, anyway," he grinned, "they didn't get us." As they plodded on, the sand became looser than ever before. The dromedaries, however, did not seem to notice the change. They plodded on with the same stiff steps. After two hours of constant traveling, the adventurers found themselves in a narrow valley between two high sand dunes. The country was gradually losing its level character and was steadily becoming more hilly. Suddenly Mr. Holton gave a cry of delight and pointed to something not far away. CHAPTER XII A Grim Discovery "What is it?" asked Bob, slow to catch sight of the object. "Gazelles," returned his father. "A small herd of them." In a moment the agile animals came running out in full view of all, their beautiful coats showing clearly in the bright sunlight. The creatures were about a hundred yards away, not any too near for an accurate shot, but the naturalists were much in desire of several as specimens. Their long-distance rifles were equipped with telescopes, making it much easier, according to the naturalists, to sight an object at a hundred yards or more. Bob's gun, however, did not have this convenience. Mr. Lewis prepared to take aim. "You take the animal to the extreme right, Howard," he said to Mr. Holton. "Bob, you pick the one in the middle, and I'll try to get one at the left. Tom," he said to Dr. Kirshner, "suppose you count to three. When you say three we'll all fire together. Let's go, now." "One, two, THREE." Bang! Three rifles spoke as one. Mr. Holton cried out in delight. "Hurrah!" he said. "Got all of the ones we aimed at. Good work." The report of the guns caused great disorder in the herd, the graceful creatures leaping about at a speed that did their thin, muscular legs full justice. Before long they had disappeared behind the sand dunes. "Now we'll ride over and see what the ones killed look like," said Mr. Lewis. As the dead gazelles were not in a direction that would take the explorers off their steady course, the pack camels were driven along also. When they reached the spot, Joe cried out in amazement at sight of the gazelles' sleek skin. It was of a yellowish brown color, and the abdomen was as white as snow. The legs were long and thin, narrowing down to a finely shaped hoof. "As beautiful an animal as one can find," declared Mr. Lewis, who with Mr. Holton had been everywhere and knew what he was talking about. "Two males and a female," observed Bob's father, noting the curved horns of the former.