The detectives began their operations after a midday meal, and having first carefully studied the Grey Room in every visible particular, they emptied it of its contents, and placed the pictures, furniture, and statuette outside in the corridor.  They asked for no assistance, and desired that none should visit the scene of their labors.  The apartment, empty to the walls, they examined minutely; with the help of ladders, they investigated the outer walls on the east and south side; and they probed the chimney from above and below.  They searched the adjoining room—­Mary’s old nursery—­to satisfy themselves that no communication existed, and they drove an iron rod through the walls in various directions, only to prove they were of solid stone, eighteen inches thick within and two feet thick without.  There was no apartment on the other side of the chamber.  It completed the eastern angle of the house front, and behind it, inside, the corridor terminated at an eastern window parallel with the Grey Room oriel, but flat and undecorated—­a modern window inserted by Sir Walter’s grandfather to lighten a dark corner.  Not a foot of the walls they left untested, and they examined and removed a portion of the paper upon them also.  Then, taking up the carpet, they broke into the flooring and skirting boards, but discovered no indication that the grime and dust of centuries had ever been disturbed.  The desiccated mummy of a rat alone rewarded their scrutiny.  It lay between great timbers under the planking—­beams that supported the elaborate stucco roof of a dwelling-room below.

To the ceiling of the Grey Room they next turned their attention, fastened an electric wire to the nearest point, and, through a trap-door in the roof of the passage, investigated the empty space between the ceiling and the roof.  Not an inch of the massive oaken struts above did they fail to scrutinize, and they made experiments with smoke and water, to learn if, at any point, so much as a pin-hole existed in the face of the stucco.  But it was solid, and spread evenly to a considerable depth.  They studied it, then, from inside the room, to discover nothing but the beautifully modeled surface, encrusted with successive layers of whitewash.  The workmanship belonged to a time when men knew not to scamp their labors and art and craft went hand in hand.  Such enthusiasms perished with the improvement of education.  They died with the Guilds, and the Unions are not concerned to revive them.

The detectives had finished this examination when, at an hour in the late afternoon, Henry Lennox and Dr. Mannering returned.  The authorities had been informed of the death of Septimus May, and desired that no more than the ordinary formalities should be taken, unless their representatives at Chadlands thought otherwise.  But they did not.  They were now convinced that no communication existed between the Grey Room and the outer world, and they declared