Ducie sat smoking his cavendish and watching his host stealthily from under his thick eyebrows. He had put a very small portion of the contents of the little packet from London into Platzoff's pipe, and he was curious to see how it would act. His intention was simply to send Platzoff into a sounder sleep than usual, and so make sure that he would not be disturbed by the unexpected waking of the Russian later in the night. For he had made up his mind that this night of all others he would steal the Great Mogul Diamond. In his own thoughts he did not use such an ugly word as _steal_ in connexion with the affair. He merely remarked as it were casually to himself, that to-night he must appropriate the Diamond. He would retire at twelve o'clock as usual. Later on, when the last sitter-up could hardly fail to be asleep, he would come back as he had come so many times of late, letting himself down by means of the rope from his own window; and so, by way of No. 4 room and the corridor, reach M. Platzoff's private rooms. Once there, he could easily deprive the unconscious Russian of his pass-key, and now that he knew the secret of the hidden door, he would have no difficulty in making his way direct into the cavern; after which, to appropriate the Diamond would be the most natural thing in the world. Returning by the way he had come, he would carefully re-lock the cavern doors and shut the secret door. He would replace the pass-key in Platzoff's pocket, and retire unseen to his own room. Not improbably days would elapse before Platzoff again went to look at his Diamond, and when he should find that it was gone--what then? Why should he, Ducie, be suspected of stealing it any more than any one else who might happen to be in the house? And even granting the worst--that Platzoff suspected him of stealing the Diamond, even charged him with stealing it? For the suspicion he did not care one groat, and the charge was one that could not be proved. The only result would be a quarrel between himself and M. Platzoff, and a premature departure from Bon Repos. All this would not be difficult to bear. The fact of the Diamond being his at last would act as a salve for all the minor ills of life. So ran Captain Ducie's thoughts as he sat smoking and watching M. Platzoff's faculties fade gradually out, like those of a very old man who has outlived his proper age. To-night the process was swifter than usual, thanks to the narcotic which he had put unseen into the Russian's pipe. He looked on with a complacent smile, caressing his moustache now and again.