The painters have given the last finishing touches to the room they have been redecorating, but before leaving they cannot resist the temptation of a joke on whoever is sent to see that all is in order. Imagine the horror of the servant-girl when she sees a great crack, perhaps half a dozen, right across the big drawing-room mirror. Meanwhile, behind her back the workmen are smiling over her discomfiture. After having sufficiently chuckled over the success of their innocent joke they offer to repair the damage, and, not to keep their victim longer in suspense, one of them takes a wet cloth and passes it over the supposed crack in the glass. Lo, a miracle! The cracks disappear under the mere touch of the damp duster, and the glass is whole again. She can hardly believe her own eyes. And yet there is no witchcraft about the matter. If you are inclined to play a similar trick, you have only to trace, with a small piece of soap, on the mirror which is to appear broken, a few fine lines in imitation of cracks. Their reflection in the glass will give them depth, and make them seem as though they extended through the thickness of the glass, while a rub with a wet flannel will make all right again.
A Parlor Zoetrope.
We have here the game of the “little horses,” so popular at Continental watering-places, brought in a simplified and innocent form within reach of everybody. Glue round the inside of the rim of a circular dish of white porcelain, a number of little cardboard figures of animals; or simply sketch thereon, with ink, similar figures or numerals, equidistant from one another. Place the dish thus furnished, in an ordinary dish of somewhat larger size, and having its centre slightly elevated—a not uncommon pattern. You will only have to give a slight impulse with the hand to the smaller plate to set it spinning within the other. Should the larger dish not be raised in the centre, you have only to pour into it a little water, enough to make the inner dish just float, and it will then revolve with great freedom, the water practically destroying all friction.
You can repeat the same figure, but with, say, the arms in different positions, so that, when the plate is set spinning, you may have depicted, in due order, the successive positions of a man raising and lowering his arms. Thus, for example, if the first figure has his arms hanging down close by his sides, the next will have them a little further from the body; the third will have them extended horizontally; the next following a little higher; and, finally, the last will have them raised above his head. Now peep, with one eye only, through a little hole made with a pin in a visiting-card or playing-card, and gaze at any given point of the circle described by the figures. When the dish is set in motion, you apparently see one figure only, but such figure seems to move like a living being, its arms appearing to take in succession the various positions which are really those of the separate figures. You may amuse yourself by thus arranging several series of such figures, their positions varied in proper succession, thus reproducing, at merely nominal expense, the scientific toy known as the Zoetrope or Praxinoscope.
A Wonderful Pin.
Take a piece of cord elastic, and through it thrust a pin bent by twisting the ends of the elastic, held vertically between the thumb and finger of each hand, and then drawing the hands apart, so as to stretch the cord, you can communicate to this latter a movement so rapid that the revolutions of the pin shall produce the shape of a glass cup. The illusion will be the more complete if the pin is itself brilliantly illuminated, while having a dark background behind it, the operator should be in a darkened room, and a single ray of sunlight from without, should fall through a hole in the shutters, upon the pin. With a little skill in manipulation one can produce, using pins bent in different ways, the semblance of the most diverse objects—say, a cheese-dish, and aquarium, a bouquet-holder, or a goblet.
Should the form of the pin tend, by reason of centrifugal force, to make it assume a horizontal position, this can be cured by securing one end of it, by means of fine white silk, to the elastic. This will usually be invisible when the pin is made to revolve as above described, and, in any case, will not affect the appearance of the figure.
Shadows on the Wall.
The exhibitor, as well as the cardboard figures, is placed behind the spectators, a position which has many advantages. Place on the table a lighted candle, and in front of it, at two or three feet distance, attach to the wall a sheet of white paper to form your “screen.” Between the light and the screen interpose some opaque body, for example, an atlas or other large book.
But under such conditions how are we to cast the shadows on the screen? Simply by the use of a mirror, placed at the side of the table. The reflection of the mirror will appear on the wall as a luminous space, oval or oblong as the case may be, and if you have placed it at the proper angle with reference to the screen, and move your cardboard shapes about cleverly between the candle and the mirror, you will forthwith see little fantastic figures projected in shadow on the screen, while the uninitiated spectator is wholly at a loss to discover how you produce them.