Suddenly a thought flashed upon him, like light in the darkness: he remembered the chimney in the room beyond. Why should he not escape in that way? At the thought a great torrent of hope swept upon him; his heart swelled as though it would burst. He rose to his feet, and feeling blindly in the blackness, came first to the table, and then to the tapestried wall beyond. Inch by inch, and foot by foot he felt his way along it, now stumbling over a cushioned couch in the darkness, and now over the edge of one of the rugs. So at last he came to the corner of the room. Thence with out-stretched fingers he felt his way along over the silent folds of the hangings until he met the emptiness of the door-way. In the same manner he crept along the wall of the room beyond, overturning in his passage a light table laden with plates and glasses, that fell with a deafening crash and tinkle of broken glass. Oliver paused for a moment in the bewilderment of the sudden noise, and then began his slow onward way again. Thus crawling slowly along, and guiding himself by the walls, he came out through the passage-way beyond the dining apartment, and so into the laboratory. Here he had no difficulty in finding the chimney, for the moonlight shed a faint, ghostly light down the broad flue above, glimmering in a pale flickering sheen upon the bottles and glass retorts that stood around. [Illustration: "CREEPING CAUTIOUSLY FORWARD, OLIVER CAME TO THE CHIMNEY-PIECE."] Creeping cautiously forward, Oliver came to the chimney-place, climbed upon one of the furnaces, and peered upward. Not twenty feet above he could see the silvery moonlit sky. Then his heart sank within him like a plummet of lead. For just over his head were grated bars of iron, thick and ponderous, that, crossing the chimney from side to side, were built into the solid brick and stone masonry of the flue. Oliver clambered down out of the furnace again, and sat him down upon the edge of it. There for a time he perched, staring despairingly into the darkness beyond. "What shall I do next?" he muttered to himself--"what shall I do next?" It could serve no use for him to stay where he was, among the crucibles and retorts; he might as well go into one of the other rooms. There, at least, would be a comfortable place to rest himself, and he began to feel heavily and stupidly sleepy. Foot by foot and step by step he felt his way back again into the farthest room. He gave no thought to that other occupant, hushed in the silent sleep of death; but flinging himself down upon the first couch that he found, gathered the musty, mildewed cushions under his head, closed his eyes, and sunk heavily into the depths of a dark, dreamless sleep. How long Oliver Munier lay in the blankness of this heavy sleep he could never know. It must have been for a great while, as he afterwards discovered. His waking was sudden and sharp, and even before he was fairly awake he knew that he heard a sound.