To While Away Winter Hours
The famous King Belshazzar was much dismayed to see the mysterious writing upon the wall of his palace. Without reducing your friends to a similar state of terror, a very easy experiment can be performed productive of the same effect, and if it does not exactly make their knees strike together, it will astonish them very much.
The appliances are such as can be found in any home, and the strange writing can be produced in the following way.
Fig. 1.—Showing relative positions of candle and mirror so that patch of light is thrown on the wall.
At one end of a dark room erect a screen that shall conceal you and your apparatus effectually from the spectators. Upon a table behind this screen place a large mirror, such as can be found upon any dressing-table. Put a lighted candle in front of this glass, placing the latter at such an angle that a large patch of light is thrown upon the wall before you, as in [Fig. 1].
The screen must, of course, hide all this from the company, who will see nothing but the light on the wall.
To write your message is now a very simple matter. Dip a coarse brush into some lamp-black water color, and, writing backwards, inscribe what you wish upon the face of the mirror. The message will then appear legibly upon the wall, seemingly written by a mysterious hand.
By dipping the brush into clean water and washing out what you have written upon the glass, the message on the wall will disappear as inexplicably as it appeared in the first place.
Fig. 2.—Thread passed round prongs of the bone.
Fig. 3.—Match through twisted thread.
A peculiar optical illusion is accomplished as follows. The wishbone of a fowl or duck should be thoroughly cleaned, and a thread passed several times around the prongs of the fork, as shown in [Fig. 2]. Having secured the thread tightly, pass a strong wooden match between the strands, twisting it several times until the prongs of the bone have been drawn closer together ([Fig. 3]).
Now, pulling out the match sufficiently to allow of one end catching against the fork, hold the bone firmly. Releasing the match it immediately describes a circle, striking against the under part of the fork, but so rapidly has it completed this revolution that the eye has been quite unable to follow it. This causes an illusion that induces all who witness the experiment to imagine that the match passes through the fork of the bone at A.
But if the eye was too slow in the last experiment, it is so officious in what is next to be described that it sees something which really does not take place.
Fig. 4.—The lion and his cage.
Draw a lion and a cage, as in [Fig. 4]. If you place a visiting card upon the line A B, and put your face so near that the right eye looks upon the lion whilst the left can see only the cage, you will observe the lion walking into his cage as naturally as if he were at the Zoo!
A rather amusing experiment, and one which will afford immense pleasure to the juvenile members of your party, is as follows:—
Cut a circular disc of stout cardboard 12″ in diameter. In the center make a hole to allow the disc to revolve easily, but not loosely, upon a wooden penholder, which should be fixed at right angles to a wooden stick ([Fig. 5]).
Fig. 5.—Disc of cardboard kept in place with penholder.
Fig. 6.—Showing box in correct position.
Upon the center of the disc fasten a cylindrical cardboard box (A, [Fig. 6]), with the penholder passing right through it. This box should be roughly 3″ high and 2″ in diameter.
At a radius of 41⁄2″ from the center describe a semicircle upon the disc at E F ([Fig. 6]), whilst upon the same half of the cylinder describe a line as G H in the same figure. Now pierce about twenty-five equidistant holes in E F and G H, joining them with thread, as in [Fig. 7].
Cover these threads with little strips of paper in such a manner as to make a plane surface, as shown in [Fig. 8]. Then fasten a cork upon the end of a wire attached to the stick, and in a cleft in this cork put a little cardboard figure as in the illustration.
Make the disc revolve by a rapid turn of the hand, and if a candle be so placed as to cast the shadow of the little man upon the disc, he will be seen engaged in making sundry passes and lunges in the manner of the perfect fencer.
Fig. 7.—Mode of joining thread.
Fig. 8.—The toy complete.
Various other figures can be made in a similar way with great success, and when cleverly managed the toy will be found most amusing.