"Yes, it's all very well, Mr Frank," said Sam, "but I don't believe that thing which carries me is half so tired as I am. Oh my! See-sawing as I've been backwards and forwards all these hours, till my spinal just across the loins feels as if it had got a big hinge made in it and it wanted oiling." "Lie flat down upon your back and rest it." "But won't the grass be damp, sir?" "Grass?" said Frank, smiling. "Where are you going to find it?" "I forgot, sir," said the man wearily. "No grass; all sand. That comes of being used to riding in a Christian country." "That's right," said the professor, joining them, for Frank had set Sam the example and was lying flat on the soft sand. "I've just been telling the Hakim to do so. Don't sit down to rest out here; lie flat whenever you get a chance. It does wonders. Are you thirsty, Frank?" "Oh no," was the reply. "That comes of travelling by night. If we had come this distance under the burning sun we should have been parched." "Better move, hadn't we?" said Frank, a minute or two later, as he glanced significantly towards Sam. "I think we had," replied the professor, laughing. "I thought it was one of the camels." The sound that came regularly was not unlike that uttered by one of the grumbling creatures, but it was due to their man's ways of breathing in his sleep, for not many seconds had elapsed before he had forgotten all his weariness, and the troubles of the first lesson in camel-riding, in a deep slumber which lasted through the two hours' halt, during which the Sheikh and his men had sat together and smoked in silence, while Frank and his companions had lain chatting in a low tone about the beauty of the moon-silvered rocks and the soft, transparent light which spread around. At last the Sheikh rose and stalked softly towards them in his long white garments, looking thoroughly in keeping with the scene, and made his customary obeisance. "Are their Excellencies rested?" he asked gravely. "Oh, yes; let us get on," said the professor, looking at his watch. "Four o'clock. I did not know it was so late. How are you, Frank? Stiff?" "Terribly." "Yes," said the doctor, stretching himself. "We have been giving some idle muscles work to do that they had never had before." "Their Excellencies will soon be as much used to it as their friend," said the Sheikh; and he led the way towards where the camels crouched, some moving their under jaws, chewing after their fashion, others with their long necks stretched straight out and their heads nestling in the sand. "Here, Sam," cried the professor, breaking the silence that reigned around, and his words were echoed from the rocks on the far side of the water-holes. But the man's reply was only a gurgling, camel-like snore. "Sound enough," said the professor; and he was stepping towards him, but Frank interposed.