He could penetrate no farther into the instructions; the cipher again changed.  He now looked steadily and earnestly round the chamber.  The moonlight came quietly through the lattice as his hand opened it, and seemed, as it rested on the floor, and filled the walls, like the presence of some ghostly and mournful Power.  He ranged the mystic lamps (nine in number) round the centre of the room, and lighted them one by one.  A flame of silvery and azure tints sprung up from each, and lighted the apartment with a calm and yet most dazzling splendour; but presently this light grew more soft and dim, as a thin, grey cloud, like a mist, gradually spread over the room; and an icy thrill shot through the heart of the Englishman, and quickly gathered over him like the coldness of death.  Instinctively aware of his danger, he tottered, though with difficulty, for his limbs seemed rigid and stone-like, to the shelf that contained the crystal vials; hastily he inhaled the spirit, and laved his temples with the sparkling liquid.  The same sensation of vigour and youth, and joy and airy lightness, that he had felt in the morning, instantaneously replaced the deadly numbness that just before had invaded the citadel of life.  He stood, with his arms folded on his bosom erect and dauntless, to watch what should ensue.

The vapour had now assumed almost the thickness and seeming consistency of a snow-cloud; the lamps piercing it like stars.  And now he distinctly saw shapes, somewhat resembling in outline those of the human form, gliding slowly and with regular evolutions through the cloud.  They appeared bloodless; their bodies were transparent, and contracted or expanded like the folds of a serpent.  As they moved in majestic order, he heard a low sound—­the ghost, as it were, of voice—­which each caught and echoed from the other; a low sound, but musical, which seemed the chant of some unspeakably tranquil joy.  None of these apparitions heeded him.  His intense longing to accost them, to be of them, to make one of this movement of aerial happiness,—­for such it seemed to him,—­made him stretch forth his arms and seek to cry aloud, but only an inarticulate whisper passed his lips; and the movement and the music went on the same as if the mortal were not there.  Slowly they glided round and aloft, till, in the same majestic order, one after one, they floated through the casement and were lost in the moonlight; then, as his eyes followed them, the casement became darkened with some object undistinguishable at the first gaze, but which sufficed mysteriously to change into ineffable horror the delight he had before experienced.  By degrees this object shaped itself to his sight.  It was as that of a human head covered with a dark veil through which glared, with livid and demoniac fire, eyes that froze the marrow of his bones.  Nothing else of the face was distinguishable,—­nothing but those intolerable eyes; but his terror, that even at the first seemed beyond nature to endure, was increased a thousand-fold, when, after a pause, the phantom glided slowly into the chamber.