Of course Captain Ducie could do nothing but accede as gracefully as possible to his host's request. He was, in truth, very well pleased to accede to it, even although the three weeks in question might do nothing towards the accomplishment of his secret hopes. Bon Repos was decidedly preferable to two stuffy rooms in a London back street, especially at a season of the year when the hegira of the fashionable world was just setting in. He would stay where he was as long as it was possible to do so. There had been no conversation between Ducie and Platzoff respecting the Diamond since the night they two had visited the cavern together. Ducie had tried to broach the subject once or twice, but Platzoff had fought so shy of it that the captain had not ventured to proceed, but had turned the conversation into other channels. It seemed to Ducie as if Platzoff half repented having taken him so fully into his confidence. It was evidently not his intention to enlighten him any further in the matter. The first week of the three had come to an end. According to custom, Ducie and Platzoff were sitting together on a certain evening in the smoke-room. It was one of the Russian's drashkil nights. He had been smoking hard and fast, and was already in a state of coma, lost to all outward influences. Ducie looked at his watch, debating within himself whether it would not be wiser on his part to go off to bed than to sit there any longer with his unconscious host. And yet it was only half-past ten--rather early for bed. He sat staring at his host, and toying absently with his watch-guard, when, clear and vivid as a shaft of lightning, there flashed across his brain a thought that struck him breathless for one moment, and the next startled him into the most intense life. He rose noiselessly to his feet, and stood for a full minute with his fingers pressed to his eyes, thinking, so it seemed to him, as he had never thought before. That one minute sufficed to elaborate the scheme that had come to him as suddenly and as startlingly as a veritable inspiration of genius. Had his thoughts clothed themselves in words, they would have expressed themselves somewhat after this fashion:-- "It is only half-past ten o'clock, and Platzoff has smoked himself into a state of unconsciousness. On no account is he ever disturbed by his valet till the clock strikes twelve: ergo, I have an hour and a half before me safe from interruption. Platzoff always carries about with him a silver pass-key that will open every door in the house, unless it be those of the bedrooms of his guests and his servants. Suppose I possess myself of that pass-key for the time being, and penetrate by its assistance into the library. Once in the library with a clear hour and a half to call my own, it will be strange if I cannot succeed in making some discovery that will prove of service to me."