The phantasmagoria lantern is generally mounted on a stand provided with castors so that it may be moved about at will. It consists of a box as represented in fig. 52, inclosing a lamp with a metallic reflector, the bundle of rays being sent through the centre of the tube containing the slide and lenses, as before described. The chimney serves to carry off the products of combustion generated by the lamp. In fig. 53 we have shown the interior of the tube containing the lenses. Between this tube and the body of the lantern there is a space within which slide the glasses whereon are painted the figures and landscapes that are to be thrown on the white screen. The luminous rays given off by the reflector in the interior of the lantern pass through a plano-convex lens placed with the flat side outwards. In front comes the double convex lens, or object-glass, which can be moved backwards and forwards by means of a rack and pinion. There is also a movable diaphragm, which is worked with a couple of cords, by pulling which the aperture is made larger or smaller at will. By moving the lantern backwards and forwards, working the rack and pinion and the diaphragm at the same time, the view seen by the spectator seems to advance and recede. The pictures are painted on glass with transparent colours, the glasses being generally about five inches in diameter. To render the illusion perfect it is necessary that the spectator should be placed in a partially dark room, being separated from the operator by the screen already mentioned. Everything being ready, the spectators having but little notion of the distance of the screen, a very small picture is shown to them first, the illumination being reduced to a minimum by pulling the cords which act on the diaphragm. The little picture first seen by them will appear to be situated at an enormous distance; but as the lantern is brought almost imperceptibly nearer to the screen, the image appears to advance towards them in a very surprising manner, at last appearing almost as if it were going to fall upon the spectators. [Illustration: FIG. 53.—The Phantascope. ]