It was curious that, when he concentrated himself on a process of reasoning, his eves seemed to lose something of their sharp brightness and grew a little dim.
At last he seemed to come to some conclusion.

He turned away from the window, drew a small magnifying-glass from his pocket, dropped on his hands and knees, and began to examine the surface of the carpet with the most minute care.
He examined a space of it nearly six feet square, stopped, and gazed round the room.

His eyes rested on the fireplace, which he could see under the bottom of the big tapestried fire-screen which was raised on legs about a foot high, fitted with big casters.

His eyes filled with interest; without rising, he crawled quickly across the room, peeped round the edge of the screen and rose, smiling.
He went on to the further drawing-room and made the same careful examination of it, again examining a part of the surface of the carpet with his magnifying-glass.

He came back to the window to which the ladder had been raised and examined very carefully the broken shutter.
He whistled softly to himself, lighted a cigarette, and leant against the side of the window.