He examined more closely a lower part of the wall, which did not fall within the shadow of the purple lamp-shade; for he was thinking of the draught which had followed the opening of the trap. By this examination he learnt two things: The explanation of the draught, and that of a peculiar property possessed by the mural decorations. These (as Soames had observed before him) assumed a new form if one stared at them closely; other figures, figures human and animal, seemed to take shape and to peer out from BEHIND the more obvious designs which were perceptible at a glance. The longer and the closer one studied these singular walls, the more evident the UNDER design became, until it usurped the field of vision entirely. It was a bewildering delusion; but M. Max had solved the mystery. There were TWO designs; the first, an intricate Chinese pattern, was painted or printed upon material like the finest gauze. This was attached over a second and vividly colored pattern upon thick parchment-like paper--as he learnt by the application of the point of his pocket-knife. The observation trap was covered with this paper, and fitted so nicely in the opening that his fingers had failed to detect, through the superimposed gauze, the slightest irregularity there. But, the trap opened, a perfectly clear view of the room could be obtained through the gauze, which, by reason of its texture, also admitted a current of air. This matter settled, M. Max proceeded carefully to examine the entire room foot by foot. Opening the door in one corner, he entered the bathroom, in which, as in the outer apartment, an electric light was burning. No window was discoverable, and not even an opening for ventilation purposes. The latter fact he might have deduced from the stagnation of the atmosphere. Half an hour or more he spent in this fashion, without having discovered anything beyond the secret of the observation trap. Again he took out his pocket-knife, which was a large one with a handsome mother-o'-pearl handle. Although Mr. Ho-Pin had examined this carefully, he had solved only half of its secrets. M. Max extracted a little pair of tweezers from the slot in which they were lodged--as Ho-Pin had not neglected to do; but Ho-Pin, having looked at the tweezers, had returned them to their place: M. Max did not do so. He opened the entire knife as though it had been a box, and revealed within it a tiny set of appliances designed principally for the desecration of locks! Selecting one of these, he took up his watch from the table upon which it lay, and approached the door. It possessed a lever handle of the Continental pattern, and M. Max silently prayed that this might not be a snare and a delusion, but that the lock below might be of the same manufacture. In order to settle the point, he held the face of his watch close to the keyhole, wound its knob in the wrong direction, and lo! it became an electric lamp!