three o’clock
Then the moon again retired behind its ethereal draperies , and darkness and silence reigned supreme . No sound could be heard , save the monotonous ticking of the clock . It struck two , and then continued its endless repetitions of the seconds . Then , three o'clock . Suddenly , something clicked , like the opening and closing of a signal-disc that warns the passing train . A thin stream of light flashed to every corner of the room , like an arrow that leaves behind it a trail of light . It shot forth from the central fluting of a column that supported the pediment of the bookcase .