clapper of the bell, as
shown at A. The arm holding the clapper must be bent to have the
point A remain as close to the strip B as possible without
touching it. The connection to the battery is made as shown. When
the time set for the alarm comes the clapper will be moved far
enough to make the contact. In the course of a minute the catch on
the clapper arm will be released and the clapper will return to
its former place.

** How to Make a Phonograph Record Cabinet [433]

The core, Fig. 1, consists of six strips of wood beveled so as to
form six equal sides. The strips are 3 ft.

[Illustration: Phonograph Wax Record Case]

long and 3 in. wide on the outside bevel and are nailed to three
blocks made hexagon, as shown in Fig. 2, from 7/8-in. material.
One block is placed at each end and one in the middle. A 1/2-in.
metal pin is driven in a hole bored in the center of each end
block. The bottoms of the pasteboard cases, used to hold the wax
records, are either tacked or glued to this hexagon core, as shown
in Fig. 3, with their open ends outward.

Two circular pieces are made of such a diameter as will cover the
width of the core and the cases attached, and extend about 1/2 in.
each side. A 1/2-in. hole is bored in the center of these pieces
to receive the pins placed in the ends of the core, Fig. 1. These
will form the ends of the cabinet, and when placed, one on each
end of the core, heavy building paper or sheet metal is tacked
around them for a covering, as shown in Fig. 4. A small glass door
is made, a little wider than one row of cases, and fitted in one
side of the covering. The outside may be painted or decorated in
any way to suit the builder.

** Experiments with a Mirror [434]

Ask your friend if he can decipher the sign as illustrated in the
sketch, Fig. 1, which you pretend to have read over the shop of an
Armenian shoemaker.

He will probably tell you that he is not conversant with Oriental
languages. He will not believe it if you tell him it is written in
good English, but place a frameless mirror perpendicularly on the
mysterious script, right across the quotation marks, and it will
appear as shown in Fig. 2. We understand at once that the
reflected image is the faithful copy of the written half.

With the aid of a few books arrange the mirror and the paper as
shown in Fig. 3 and ask your friend to write anything he chooses,
with the condition that he shall see his hand and read the sc