They were made of mahogany, substantial and old-fashioned, with elaborate flutings between each compartment, and were crowned with carved bosses of fruit and flowers intermixed. Every shelf was completely filled with books, none of which were dummies, as Captain Ducie took care to verify. Beginning at the right-hand corner, he went completely round the room. The fireplace, too, came in for an amount of critical examination such as had probably never been bestowed on it before. The window that gave light to the library was in the outer wall of the house, and looked on to the lawn. Like all the windows in M. Platzoff's private suite it was crossed and recrossed by some half-dozen iron bars artfully let into the woodwork so as not to be visible from without. The outside walls of Bon Repos were of an antique thickness, as though they had been built to last a thousand years. They were, in fact, quite thick enough to allow of a narrow staircase being hollowed out of their substance. It seemed, therefore, to Ducie just as necessary to examine carefully that side of the room as it did to examine the inner side. He examined both the sides and the ends, carefully, thoroughly; but the result of his examination was that he was exactly as wise when he left off as when he began. Not a crevice, not a cranny, not a discoloration of the wood, not the faintest trace of a secret spring was anywhere to be found. He tapped each panel and compartment separately with his knuckles, but he was unable to trace any difference in the dull dead sound given out by each and all. Then he went down on his knees to examine the carpet. It was a sombre velvet pile, and was nailed down at the edges with a number of small tin-tacks driven through it into the floor. The corners of the carpet had not been carefully swept, and the tiny indentations in it where it was pressed down by the heads of the tacks were full of dust. "Now," argued Captain Ducie with himself, "if the entrance to the cavern where the Diamond is hidden is through an opening in the floor of this room, then, in order to reach that opening this carpet or a portion of it must be taken up. Is it likely that M. Platzoff, who by his own account visits his Diamond at least once a week, would take up and nail down his carpet every time he wishes to look on his wonderful gem? Further: if the carpet had been lately taken up, the indentations caused by the heads of the nails would not be full of dust as they are now. The nails now in have not been touched for a month at the least."