Not knowing what to expect, Perry curled his toes under the cross-bar, getting a grip as though a camel were a bucking horse. This was nearly his downfall, for Perry did not know that a camel rises on his hind-legs first. As the beast rose, it pitched the saddle at such an angle that the lad felt sure he was about to be thrown over the animal’s back. He had just time to uncurl his legs and put a foot on the cross-step to brace himself, when, after a distinct pause, the camel gave a muscular jerk and came up on its fore-legs also, and the boy settled back into his seat. The beast stood still for a moment, and then began to move. “Is—is this camel double-jointed, Uncle George?” asked Perry, the words being jolted out of his mouth, as he ranged up beside the professor, who meanwhile had mounted his animal nonchalantly. “I don’t suppose so,” was the answer. “Why?” “The way he walks,” replied the boy. “It feels as though his nigh and his off sides had become unhitched, somehow.” The leader of the expedition laughed at the description, although realizing that it did give an idea of the loose, racking gait of the camel. “They all walk like that,” he said. “You get used to it, after a time.” “It’s sure queer,” said Perry, “but it’s rather fun.” [Illustration: WAITING FOR THE LOAD. ROARING AT THE WEIGHT. RISING, STILL PROTESTING. READY FOR DESERT MARCH. _Courtesy of American Museum of Natural History._ A CAMEL BEING LOADED WITH HALF-TON FOSSIL CASES.] “Tell me, after the halt, if you think it’s as much fun,” the scientist warned him. For the next half-hour the lad was silent, watching the caravan tune up to start. At last the long line was ready, Michawi took the lead, the soft-padded feet of the camel shuffled on the beaten road to the south, along the western bank of the Nile, and the trip toward the desert was begun. In single file, there was little chance for speech, and Perry’s desire for questioning grew gradually less as the camel swung into that long, slouching walk, which at the never-changing pace of two and a half miles an hour, eats up the desert miles. So absolutely regular is this pace that distances on the desert are measured by caravan hours, and the average day’s journey is six caravan hours or fifteen miles. Racing camels, however, which are an Arabian breed, specially bred for speed, have been known to carry a traveler as much as a hundred miles a day, but these are seldom used in caravans. Perry had not been in the camel-saddle more than about half-an-hour before he began to feel as though he were sea-sick. He choked down the feeling, but it made him miserable and unhappy. His back, too, was beginning to hurt from the motion, and when, after what seemed an age, the caravan halted for lunch, it was a stiff and weary lad who stepped off gladly from his camel when the beast knelt down. “How are you feeling?” asked his uncle.