quarters of an hour. Nothing happened, and he now determined to proceed with his inquiries.
Sitting upon the edge of the bunk, he looked about him, first directing his attention to that portion of the wall immediately above. So cunningly was the trap contrived that he could find no trace of its existence. Carefully balancing himself upon the rails on either side of the bunk, he stood up and peered closely about that part of the wall from which the sound had seemed to come. He even ran his fingers lightly over the paper, up as high as he could reach; but not the slightest crevice was perceptible. He began to doubt the evidence of his own senses.
Unless his accursed imagination had been playing him tricks, a trap of some kind had been opened above his head and someone had looked in at him; yet—and his fingers were trained to such work—he was prepared to swear that the surface of the Chinese paper covering the wall was perfectly continuous. He drummed upon it lightly with his finger-tips, here and there over the surface above the bed. And in this fashion he became enlightened.
A portion, roughly a foot in height and two feet long, yielded a slightly different note to his drumming; whereby he knew that that part of the paper was not attached to the wall. He perceived the truth. The trap, when closed, fitted flush with the back of the wall-paper, and this paper (although when pasted upon the walls it showed no evidence of the fact) must be transparent.
