The first thing to be done was to satisfy himself that Platzoff was really and truly unconscious. Taking him by the arm, he shook him, gently at first, and then with greater violence. But the Russian only uttered a low, inarticulate moan of protest. Then Ducie ventured to lift up one of his eyelids. The glazed, fishy look of the eye below it was sufficient to convince him that from Platzoff himself he had nothing to fear. Then with a light-fingered dexterity that would not have discredited a professional pickpocket he began to search for the silver key. He was not long in finding it. There it was, in a small inner pocket of Platzoff's vest. He drew it out with a heart that beat a little faster than common. So far all was well. He stood for a few moments with the key in his fingers, listening intently. Not a sound of any kind inside the house or out. As he stood thus, he bethought himself of a little brass bolt on the inside of the door that, opened into the corridor. By means of this bolt Platzoff could at will secure himself even against the intrusion of Cleon. This bolt Ducie now shot noiselessly into its socket. If Cleon--or rather Jasmin, now that Cleon was ill--were inadvertently to come before his proper hour, he would have to wait till the door was opened for him from within. Having thus secured himself against any possible interruption, Ducie, after taking a last glance at his host, walked boldly across the room, and applying the key, opened the inner door and passed forward into the dressing-room. From the dressing-room he gained access to the bedroom, and from thence into the library. The latter room being in entire darkness, he had to go back into the bedroom for a candle, two of which were always lighted there at dusk and kept burning till M. Platzoff went to bed. As already stated, the library had two doors opening into it, one that gave from the bedroom, and another that faced you as you went in. A brown curtain fixed by means of rings on a brass rod hung before this second door. Ducie never remembered having seen this curtain more than three parts drawn, leaving visible a small portion of the door. In fact, it appeared to him, considering the matter, as though the curtain were never touched, its exact position seemed so unaltered from time to time. His first idea on his first visit to the library after his sight of the Diamond, had been that through this second door lay the secret entrance to the cavern. But it was an idea that found no resting place in his mind. The Russian was not the sort of man to adopt such a palpable expedient as an ordinary door to mark the entrance to the secret staircase. Ducie had felt convinced at the time that behind those ponderous bookshelves lay the hidden entrance, and he was equally convinced of it to-night. Therefore, instead of taking any notice of the second door, he at once proceeded, candle in hand, to make an examination of the shelves.