THE PHANTASMAGORIA
In showing the common magic-lantern, the spectators see a round circle of light with the figures in the middle of it; but in the Phantasmagoria they see the figures only, without any circle of light. The exhibition is produced by a magic lantern, placed on that side of a half-transparent screen which is opposite to that on which the spectators are, instead of being on the same side, as in the ordinary exhibition of the magic lantern. To favor the deception, the slides are made perfectly opaque, except in those places that contain the figures to be exhibited, and in these light parts the glass is covered with a more or less transparent tint, according to the effect required. The easiest way is to draw the figures with water colors on thin paper and afterward varnish them. To imitate the natural motions of the objects represented, several pieces of glass placed behind each other are occasionally employed. By removing the lantern to different distances, and at the same time altering, more or less distinct, at the pleasure of the exhibitor; so that, to a person unacquainted with the effect of optical instruments, these figures appear actually to advance and recede. Transparent screens for the Phantasmagoria are prepared by spreading white wax, dissolved in spirits of wine or oil of turpentine, over thin muslin; a screen so prepared may be rolled up without injury. A clearer screen may be produced by having the muslin always strained upon a rectangular frame, and preparing it with turpentine, instead of wax; but such a screen is not always convenient, and cannot be rolled without cracking, and becoming in a short time useless.
CHINESE SHADOWS
In a partition wall cut an aperture of any size; for example, four feet in length and two in breadth, so that the lower edge may be about five feet from the floor, and cover it with white Italian gauze, varnished with gum-copal. Provide several frames of the same size as the aperture, covered with the same kind of gauze, and delineate upon the gauze different figures, such as landscapes and buildings, analogous to the scenes which you intend to exhibit by means of small figures representing men and animals. These figures are formed of pasteboard, and their different parts are made movable, according to the effect intended to be produced by their shadows, when moved backward and forward behind the frames, at a small distance from them. To make them act with more facility, small wires, fixed to their movable parts, are bent backward and made to terminate in rings, through which the fingers of the hand are put, while the figure is supported on the left by means of another iron wire. In this manner they may be made to advance or recede and to gesticulate, without the spectators observing the mechanism by which they are moved; and as the shadow of these figures is not observed on the paintings till they are opposite those parts which are not strongly shaded, they may thus be concealed and made to appear at the proper moments, and others may be occasionally substituted in their stead.
It is necessary, when the figures are made to act, to speak a dialogue, suited to their gestures, and imitate the noise occasioned by different circumstances. The paintings must be illuminated from behind by means of a reverberating lamp, placed opposite to the center of the painting, and distant from it about four or five feet. Various amusing scenes may be represented in this manner by employing small figures of men and animals, and making them move in as natural a way as possible, which will depend on the address and practice of the person who exhibits them.
A WONDERFUL MIRROR
Make two openings of a foot high and ten inches wide and about a foot distant from each other, in the wainscoting of a wall; let them be at the common height of a man's head; and in each of them place a transparent glass, surrounded with a frame, like a common mirror. Behind this partition place two mirrors, one on the outward side of each opening, inclined to the wainscot at an angle of forty-five degrees; let them both be eighteen inches square; let all the space between them be enclosed by boards or pasteboard, painted black and well closed, that no light may enter; let there be also two curtains to cover them, which may be drawn aside at pleasure. When a person looks into one of these supposed mirrors, instead of seeing his own face he will perceive the object that is in the front of the other; so that, if two persons present themselves at the same time before these mirrors, instead of each one seeing himself, they will reciprocally see each other. There should be a sconce with a candle or lamp placed on each side of the two glasses in the wainscot, to enlighten the faces of the persons who look in them, otherwise this experiment will have no remarkable effect. This recreation may be considerably improved by placing the two glasses in the wainscot in adjoining rooms, and a number of persons being previously placed in one room, when a stranger enters the other, you may tell him his face is dirty, and desire him to look in the glass, which he will naturally do; and on seeing a strange face he will draw back; but returning to it, and seeing another, another and another, what his surprise will be is more easy to conceive than express.
When one looks in a mirror placed perpendicularly to another, his face will appear entirely deformed. If the mirror be a little inclined, so as to make an angle of eighty degrees (that is, one-ninth part from the perpendicular), he will then see all the parts of his face, except the nose and forehead; if it be inclined to sixty degrees (that is, one-third part), he will appear with three noses and six eyes; in short, the apparent deformity will vary at each degree of inclination; and when the glass comes to forty-five degrees (that is, half-way down), the face will vanish. If, instead of placing the two mirrors in this situation, they are so disposed that their junction may be vertical, their different inclinations will produce other effects, as the situation of the object relative to these mirrors is quite different.
THE DISAPPEARING PAPER
Attach to a dark wall a round piece of paper an inch or two in diameter, and, a little lower, at the distance of two feet on each side, make two marks; then place yourself directly opposite to the paper, and hold the end of your finger before your face in such a manner that when the right eye is open it shall conceal the mark on the right; if you then look with both eyes to the end of your finger, the paper, which is not at all concealed by it from either of your eyes, will, nevertheless, disappear.