The next instant three red balls of fire fell from the airship earthwards in rapid succession, and within a couple of minutes a faint gleam of greenish light fell like an arc in the north-western sky. "Yes, the patrols have found us, sure enough," exclaimed the captain, who had now joined the officer. After several further exchanges of fire-balls, repeated now from two or three quarters, the searchers closed in upon the straggler. Then a rapid dialogue took place by means of the morse lamp, and, when dawn came, shortly afterwards, no less than six fighting scouts, running at about a quarter throttle, surrounded the wounded leviathan, and escorted her towards Cairo. When the _Empress_ reached that town, she was already twenty-four hours overdue at London, so the cables and the wireless stations were busy with messages relating to the missing liner, and with more than one inquiry as to the safety of her cargo, evidently from the consignees, or more likely still, from the underwriters. And when the captain told his story to the Commissioner of Aerial Police at Cairo there was another mighty stir, and both the cables and the wireless were busy again, for the whole civilized world was tingling with excitement to know something tangible about this man of mystery--the phantom airman. And the story of Gadget’s photographs was told to the world. *CHAPTER XV* *DIAMOND CUT DIAMOND* While the events recorded in the last few chapters were taking place, a series of adventures not less exciting and perilous had befallen the two airmen, Keane and Sharpe, in their endeavours to track that ingenious conspirator, Professor Rudolf Weissmann, in his secret retreat within the dark recesses of the Schwarzwald. After their midnight consultation with Colonel Tempest at Scotland Yard, their instructions were to proceed early next day, by whatever aircraft was then available, to Germany, and once there to adopt some suitable disguise, and institute forthwith a most rigorous search for the secret aerodrome. They were to leave no stone unturned in their efforts to track down this great German irreconcilable, who had dared to hold a pistol at the civilized world, and to bring back, if possible, some tangible clue concerning his two great discoveries. "Time is short," the colonel said. "Immediate action on our part is vital. Spare no expense in the venture, and if necessary you must even proceed to extreme measures to capture this daring outlaw and his accomplices." "And what about this phantom aeroplane?" asked Keane. "Apparently it has already left the Schwarzwald on its piratical expedition." "It may return, and you must watch for it. Some of those scattered inhabitants of the Black Forest are sure to have seen or heard something of it. Its trial trips must have been carried out somewhere in the vicinity."