She shook her head. "Sometimes I have wondered----" she said reflectively. "He seemed different from the others, and there has been so much that I could never understand. But then again there were times when he seemed pure Arab," she added in a lower voice and with an involuntary shiver. "You ought to know," said Saint Hubert. "Yes!" he went on firmly, as she tried to interrupt him. "It is due to you. It will explain so many things. I will take the responsibility. His father is the Earl of Glencaryll." "But I know him," said Diana wonderingly. "He was a friend of my father. I saw him only a few months ago when Aubrey and I passed through Paris. He is such a magnificent-looking old man, so fierce and sad. Oh, now I know why that awful frown of Ahmed's has always seemed so familiar. Lord Glencaryll frowns like that. It is the famous Caryll scowl. But I still don't understand." She looked from Saint Hubert to the unconscious man on the divan and back to Saint Hubert with a new trouble growing in her eyes. "I had better tell you the whole story," said Raoul, dropping back into his chair. "Thirty-six years ago my father, who was as great a wanderer as I am, was staying here in the desert with his friend the Sheik Ahmed Ben Hassan. A chance acquaintance some years before over the purchase of some horses had ripened into a very intimate friendship that was unusual between a Frenchman and an Arab. The Sheik was a wonderful man, very enlightened, with strong European tendencies. As a matter of pure fact he was not too much in sympathy with the French form of administration as carried on in Algeria, but he was not affected sufficiently by it to make any real difficulty. The territory that he regarded as his own lay too much to the south, and he kept his large and scattered tribe in too good order for any interference to be possible. He was unmarried, and the women of his own race seemed to have no attraction for him. He was wrapped up in his tribe and his horses. My father had come for a stay of some months. My mother had recently died and he wanted to get away from everything that reminded him of her. One evening, shortly after his arrival at the camp, a party of the Sheik's men who had been absent for some days in the north on the chief's affairs arrived, bringing with them a woman whom they had found wandering in the desert. How she had got there, or from what direction she had come, they did not know. They were nearer civilisation than Ahmed Ben Hassan's camp at the time, but with true native tendency to avoid responsibility they thought that the disposal of her was a matter more for their Sheik than themselves. She could give no account of herself, as, owing to the effects of the sun or other causes, she was temporarily out of her mind. Arabs are very gentle with any one who is mad--'Allah has touched them!' She was taken to the tent of one of the headmen, whose wife looked after her. For