Anglo-Saxondom, and therefore Christendom, lay at his mercy but for this guardian power of the air. Its millions were unarmed and its wealth unprotected. Its indolent and luxurious democracies, occupied solely with social experiments and the increase of their material magnificence, would be crushed almost without resistance by his splendidly armed and disciplined legions. The Crescent would replace the Cross above their temples, and the world would be a Moslem planet but for this empire of the air, universal and unconquerable, which barred his way to the dominion of the world and the final triumph of his faith. For the hundredth time he had revolved the hopeless dilemma in his mind, alternately looking upon the conquests he longed for, and on the splendid but useless forces at his command, when a huge, strange shape dropped swiftly and silently out of the sky overhead, and, as though in answer to the unspoken call of his intense longing, one of those very air-ships of which he had been thinking with such angry despair swept with a majestic downward sloping curve out of the dusk of the night, and ran up close alongside the low parapet of the terrace on which he was standing. It was the first time he had ever seen one of these marvellous vessels, which were the talk and the wonder of the world, at such close quarters. Paralysed for the moment by mingled curiosity and amazement, he recoiled with a startled invocation to the Prophet on his lips, and then stood staring at it in silence, wondering whether the strange apparition meant the visit of a friend or an enemy. While he was standing thus the air-ship drifted as silently as a shadow over the parapet, and sank gently down until it rested on the marble floor of the vast terrace. Then a sliding door opened in the after-part of the glass dome which covered the deck from stem to stern, a light metal stairway fell from it, and three men richly and yet simply dressed descended to the terrace and advanced to where he stood. Two of them halted at a respectful distance, and the third, a man whose dignity of bearing was enhanced by the snowy whiteness of his hair and beard, advanced alone, and with a grave and courteous gesture of salute said in English, the language of universal intercourse-- “Am I right in believing this to be the palace of his Majesty the Sultan?” It was some moments before Khalid recovered his composure sufficiently to answer the question, simple as it was. His wonder was increased tenfold when he saw that his visitor from the skies did not wear the golden wings which were the insignia of the Aerians. Was it possible that some other inhabitants of the earth had, in spite of the rigid prohibition of the Supreme Council, managed to build an aerial navy? His heart leapt with exultation at the thought. Obeying the impulse of the moment, he took a stride forward and held out his hand, saying--