At that moment something gleamed through the air, whizzed past my ear, and fell with a metallic jingle on the stones! Instinctively we both looked up. At an unlighted window on the first floor I caught a fleeting glimpse of a dark face. “You were right!” I said. “Ali of Cairo has forestalled us!” Harley stooped and picked up a knife with a broad and very curious blade. He slipped it into his pocket, nonchalantly. “All evidence!” he said. “Keep in the shadow and bend down. I am going to stand on your shoulders and get into that window!” Wondering at his daring, I nevertheless obeyed; and Harley succeeded, although not without difficulty, in achieving his purpose. A moment after he had disappeared in the blackness of the room above. “Stand clear, Knox!” I heard. Two of the cushion seats sometimes called “poof-ottomans” were thrown down, and: “Up you come!” called Harley. “I'll grasp your hands if you can reach.” It proved no easy task, but I finally managed to scramble up beside my friend--to find myself in a dark and stuffy little room. “This way!” said Harley rapidly--“upstairs.” He led the way without more ado, but it was with serious misgivings that I stumbled up a darkened stair in the rear of my greatly daring friend. A pistol cracked in the darkness--and my fez was no longer on my head! Harley's repeater answered, and we stumbled through a heavily curtained door into a heated room, the air of which was laden with some Eastern perfume. In the dim light from a silken-shaded lantern a figure showed, momentarily, darting across the place before us. Again Harley's pistol spoke, but, as it seemed, ineffectively. I had little enough opportunity to survey my surroundings; yet even in those brief, breathless moments I saw enough of the place wherein we stood to make me doubt the evidence of my senses! Outside, I knew, lay a dingy wharf, amid a maze of mean streets; here was an opulently furnished apartment with a strong Oriental note in the decorations! Snatching an electric torch from his pocket, Harley leaped through a doorway draped with rich Persian tapestry, and I came close on his heels. Outside was darkness. A strong draught met us; and, passing along a carpeted corridor, we never halted until we came to a room filled with the weirdest odds and ends, apparently collected from every quarter of the globe. Crack! A bullet flattened itself on the wall behind us! “Good job he can't shoot straight!” rapped Harley. The ray of the torch suddenly picked out the head and shoulders of a man who was descending through a trap in the floor! Ere we had time to shoot he was gone! I saw his brown fingers relax their hold--and a bundle which he had evidently hoped to take with him was left lying upon the floor. Together we ran to the trap and looked down. Slowly moving tidal water flowed darkly beneath us! For twenty breathless seconds we watched--but nothing showed upon the surface.