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, the position of the lens, the images are made to increase and diminish, and to become 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.