It was a circular room, like my own chamber below, but much loftier, and without any sign of windows. A mild half-light descended from a ring of shaded lamps affixed round the walls at a height of nine feet from the floor, leaving the vaulted ceiling in shadow. The walls below the lamps were draped with a kind of tapestry of rich dark hues; and at one side stood a tall carved cabinet of black wood, furnished with a pair of folding-doors and a broad desk, upon which were books and some small instruments of polished brass. On the side opposite the cabinet was a deep niche in the stone wall, supporting a slender antique vase of embossed silver. These particulars I noticed but passingly: that which immediately and predominantly commanded my attention was the mighty instrument which, with its appurtenances, rose pyramid-like in the centre of the room; lifting heavenward its awful eye, that had looked familiarly upon the mysterious faces of the planets, and revealed their secrets to man. The upper portion of the shaft was enveloped in the obscurity which brooded in the vault; but this dusky veil only deepened its impressiveness. Below, the softened lamplight shone upon a complex arrangement of machinery; wheels and grooves and chains, and subtle levers, all artfully contrived to turn and slide without jar or irregularity, obedient to the light touch of Diana's taper finger. She was the priestess of this temple; here were her virgin stronghold and her home. During the few moments that I had been plunged in contemplation she had thrown on, over the black silk demi-toilette which she had worn during the evening, a flowing mantle of delicate texture, dark as night, with wide drooping sleeves, and falling in soft folds from her shoulders to the floor. Upon her auburn hair she had placed a black velvet cap, such as the astrologers of old used to wear; and as she now stood before me, smiling at me out of her unfathomable nixie eyes, she looked more like an enchantress, wise with the arts of witchcraft than like a mortal maiden with warm blood and human affections. Was she a witch indeed? 'This clockwork can be adjusted so as to keep any one of the stars or planets within the field of the telescope,' said she, quietly, laying her hand upon one of the wheels. 'I have only to move this, and one of these, and then there is nothing more to be done but to sit in the chair, there, and look through the lens.' 'Shall we see the moon to-night?' I asked. 'Yes, if you like.' She pressed a lever somewhere in the machinery, and immediately the vast tube, that seemed fixed so immovably, swung noiselessly and steadily towards the right, and, pausing there without shock or tremor, waited motionlessly as before. 'It looks at the moon now,' said Diana in a low voice.