"Do you promise, Captain?" asked his interrogator, looking at him fixedly. "Yes, I promise." "On your honour?" "On my word of honour, I promise to deliver it." "Then good-bye. I will ’wireless’ the patrols to look out for you." "Thank you," replied the skipper acidly. And the next moment, seeing that only his own accomplices and reputed subjects were left on the ground, the Sultan gave the order, "Let go!" So the huge cable was slipped, and the leviathan left her moorings at once. The north-west wind carried her clear of the trees, and, as she had left nearly two tons of her most precious cargo behind, she rose rapidly, then started falteringly on her long journey to Cairo as her two remaining Sunbeam-Maori engines burst into life. The sun, which had shone with pitiless might upon the Arabian desert that day, was sinking like a huge red ball beneath the horizon when the great air-liner, drifting considerably from her course, but still making progress in her journey towards Cairo, disappeared from the watchers’ view. With strange impartiality, inexplicable in such a robber-bandit, the spoil had been divided amongst the Bedouins, who, to their bewilderment and surprise, were now rich, each one of them, beyond the dreams of avarice. Their gratitude to Allah, the Giver of all Good, and to the great white sheik was unbounded. Never before had their greedy eyes beheld such treasure; never before had they gained a prize so easily; and some of them even wondered whether, after all, Mohammed had not appeared to the Faithful once more in the person of the great white sheik. Long before midnight, however, the last man, with heavily-laden beast of burden, had disappeared, swallowed up, as it were, by the very sands of the desert, so that, when the full round moon approached the meridian and changed the gold of the desert to silver, not a vestige of man or beast remained. And of the camp, only a few ashes marked the spot where once a fire had burned. The _Scorpion_, too, had taken its departure for an unknown destination, carrying its mysterious crew far, far away from these burning sands, for the indomitable commander knew only too well that the captain spoke truthfully when he said that the arm of Britain was very long, and could even reach to this wild desert land. Before his departure, however, Heinrich von Spitzer had sent off his promised message in laconic terms to the Cairo patrols. It ran as follows:-- "Air-liner _Empress_ with damaged engines crossing desert towards Cairo. Lat. 29-50 N., Long. 40-25 E. drifting W.S.W. Wireless deranged. SCORPIO." "Piece of bad luck, sir!" remarked the commissioner’s assistant at Cairo when he received the message. "H’m! She carries the Indian mail, too," replied his chief. "Yes, and a good deal more, sir." "What else does she carry this trip besides passengers and mails?" asked the alert commissioner.