ectangular frame out of pine wood, 1/4 by 1/2 in., as
shown in the sketch. It is made a little wider and a little
shorter than the film to be dried. This will allow the end of the
film to be turned over at each end of the frame and fastened with
push pins. Do not stretch the film when putting it on the frame as
it shrinks in drying. The film will dry quicker and will be flat
when dried by using this frame.
--Contributed by Elmer H. Flehr, Ironton, Ohio.

** A Home-Made Novelty Clock [446]

This clock that is shown in the accompanying engraving is made in
scroll work, the cathedral and towers being of white maple, the
base is of walnut with mahogany trimmings, all finished in their
natural colors. It has 11 bells in the two towers at the sides and
13

[Illustration: Clock]

miniature electric lamps of different colors on two electric
circuits. The clock is operated by a small motor receiving its
power from dry cell batteries. This motor turns a brass cylinder
over which runs a continuous roll of perforated paper similar to
that used on a pianola. A series of metal fingers, connected by
wires to the bells, press lightly on this brass roll and are
insulated from the roll by the perforated paper passing between.
When a perforation is reached a finger will make a contact with
the brass roll for an instant which makes a circuit with the
magnet of an electric hammer in its respective bell or forms the
circuit which lights the electric bulbs as the case may be.

At each hour and half hour as the clock strikes, the motor is
started automatically and the chimes sound out the tunes while the
colored lights are turned on and off; two small doors in the
cathedral open and a small figure comes out while the chimes are
playing, then returns and the doors are closed.
--Contributed by C. V. Brokenicky, Blue Rapids, Kansas.

** Fourth-of-July Catapult [447]

Among the numerous exciting amusements in which boys may
participate during the Fourth-of-July celebration is to make a
cannon that will shoot life-sized dummies dressed in old clothes.
Building the cannon, as described in the following, makes it safe
to fire and not dangerous to others, provided care is taken to
place it at an angle of 45 deg. and not to fire when anyone is
within its range. The powder charge is in the safest form
possible, as it is fired with a blow from a hammer instead of
lighting a fuse. If the cannon is made according to directions,
there ca