The same hour next night saw Captain Ducie behind the curtained door. He knew that several nights might elapse before Platzoff should visit the Diamond, and he was quite prepared to wait there night after night till his perseverance should be crowned with success. It was just as well, perhaps, that he had made up his mind to play a waiting game, seeing that five nights passed one after another, on no one of which did he fail in his watch at the curtained door, before Platzoff, taking counsel with himself, made up his mind to again visit the cavern. It was on a certain night--or rather morning, being about three a.m.--after one of his drashkil debauches, that the Russian so made up his mind. Ducie was in patient waiting. From his hiding-place behind the curtain he heard Platzoff get out of bed. When he saw him put on his dressing-gown and light a small lamp--the same that the Russian had made use of on the night that Ducie accompanied him--then the latter knew that his patience was about to be rewarded. As Platzoff advanced into the library, Ducie shrank back, and noiselessly closed the door that led into the corridor. He thought it just possible that Platzoff might lift the curtain to make sure that there was no one in hiding. Standing with his hand on the door, and listening intently, Ducie could hear Platzoff moving about the library. Then he heard the click of a spring or bolt, and a sound like the rolling back of a door or panel. Then all was still. After waiting for a couple of minutes, during which the silence remained unbroken, Ducie slowly opened the door, and moved forward till his face nearly touched the curtain. He could hear nothing save the beating of his own heart. Drawing the curtain an inch or two on one side, he peeped. The library was empty, and the secret door was open. For a few seconds he felt like a man in a dream; he could hardly believe in the reality of what he saw before him. But the thought that in ten or twelve minutes at the farthest M. Platzoff would be back again, and that now or never was his opportunity, quickened him into action. His object tonight was to take such accurate note of the position of the secret door, and the means by which it was opened and shut, as would enable him in time to come to find it again without much difficulty. Platzoff was in the cavern below, and till the sound of his returning footsteps could be heard Ducie knew that he was safe.