黑暗时代（下篇）(6)

Once, by moonlight, he attempted to climb the cliffs behind the laboratory, working his way hazardously from coign to coign. He abandoned the attempt only when he came to an overhanging wall of rock that was smooth as beaten metal. There came the day when Torquane, revisiting the woods that pressed close upon the laboratory garden, grew aware of an unwonted silence weighing oppressively upon all things. For a few instants he was puzzled, failing to comprehend the cause, Then he realized that the silence was due to a cessation of that humming noise which had signalized the presence of the barrier.