“And then suddenly in the silence I heard a sound which sent my heart into my mouth. It was the clank of the levers and the swish of the leaking cylinder. He had set the engine at work. The lamp still stood upon the floor where I had placed it when examining the trough. By its light I saw that the black ceiling was coming down upon me, slowly, jerkily, but, as none knew better than myself, with a force which must within a minute grind me to a shapeless pulp. I threw myself, screaming, against the door, and dragged with my nails at the lock. I implored the colonel to let me out, but the remorseless clanking of the levers drowned my cries. The ceiling was only a foot or two above my head, and with my hand upraised I could feel its hard, rough surface.