"Be careful how you act," he added. "If they suspected you of prying something disagreeable might happen to you." I was not surprised at his warning, for I knew the character of some of the international crooks who were Rayne's "friends." But surely the banker Zuccari could not be a crook? If he were, then he was a master-criminal like Rayne himself. If so, what was the motive of his close association with the Marchesa Romanelli? I had noticed when at the palazzo that he seemed infatuated with her, yet she no doubt little dreamed of his active association with such a person as Hauser. It seemed quite plain that whatever the truth the Admiral had no suspicion of his wife. Zuccari and Hauser still remained in Zurich, so, though I had arranged with Madame and Lola to return with them to Naples, I sent them back alone and remained to watch. On the night of their departure I was tired and must have slept soundly after a heavy day, when I was suddenly awakened by a strong light flashed into my face, and at the same instant I saw a hand holding a silken cord which had been slowly slipped beneath my ear as I lay upon the pillow. For a second I held my breath, but next moment I realized that I was being attacked, and that the cord being already round my neck with a slip-knot, those sinewy hands I had seen in the flash of light intended to strangle me. My only chance was to keep cool. So I grunted in pretense of being only half-awake, and turning very slightly to my side, my hand slowly reached against my pillow. At any second the cord might be drawn tight when all chance of giving the alarm would be swept away from me. Yet my assailant was deliberate, apparently in order to make quite certain that the cord around my neck should effect its fatal purpose. Of a sudden I grasped what I had against my pillow--a small rubber ball--and suddenly shooting out my hand in his direction, squeezed it. A yell of excruciating pain rang through the hotel, and he sprang back, releasing his hold upon the cord. Then next moment, when I switched on the light, I found the man Hauser dancing about my room, his face covered with his hands--blinded, and his countenance burnt by the dose of sulphuric acid I had, in self-defense, squirted full into it. For defense against secret attack the rubber ball filled with acid Rayne always compelled me to carry, as being far preferable to revolver, knife or sword-cane. It is easily carried, easily concealed in the palm of the hand, makes no noise, and if used suddenly is entirely efficacious. My assailant, blinded, shrieking with pain, and his face forever scarred, quickly disappeared to make what excuse he might. Later I found that he had previously tampered with the brass bolt of my door by removing the screws of the socket, enlarging the holes and embedding the screws in soft putty so that on turning the handle and pressing the door the socket gave way and fell noiselessly upon the carpet!