INDOOR FIREWORKS
WITHOUT THE USE OF EXPLOSIVES
A FIREWORK display without the employment of brimstone and saltpeter is
somewhat unusual. But it is quite possible to give such a display, and
to do so without the heavy expense usually attending Fourth of July
pyrotechnics.
It is first necessary to make a frame or “stage,” upon which to present
the firework display. In appearance this frame greatly resembles a
three-winged clothes-horse; in fact, one of these humble home
“thoroughbreds” may, after slight alteration, be easily pressed into
service.
[Illustration: FIG. 1.--Showing frame and side wings.]
The question of dimensions rests entirely with the exhibitor. Fig. 1
shows a diagram of the frame. As will be seen, its front is divided into
two compartments, A and B. The lower compartment, B, is occupied by a
scene of some Exposition Building. This must be made of cardboard, and
can either be permanently nailed to the frame, or so constructed as to
slide in and out between two grooves. The advantage of the latter mode
of fixture is that when the owner of the firework show tires of one
scene he can readily substitute another.
To represent the windows and glass domes of the Exposition Building,
small squares should be cut from the cardboard scene and tissue paper
pasted over them. When a light is placed behind, the effect will be very
pleasing, and will considerably enhance the reality of the firework
display.
After draping the two side wings (C and D, Fig. 1) with red or green
cloth, the framework or “stage” may be set aside, and attention paid to
the fireworks themselves. They are by no means of a character calculated
to send cold shivers down the backs of timid parents. Fig. 2 shows a
portion of one. It simply consists of a piece of cardboard, slightly
larger than the top frame (A, Fig. 1).
A design similar to that in the diagram must be lightly penciled upon
it. Then, with a rather coarse needle, prick out this design with a
series of small holes, through which the light can easily penetrate. It
is also necessary to make four larger holes at each corner of the card,
and to drive four wooden pegs or nails into the corresponding corners of
the frame. By means of these the cardboard design can be quickly removed
from or fixed to the “stage.” (See D, Fig. 4.)
[Illustration: FIG. 2.--Showing firework design formed by series of
small holes.]
[Illustration: FIG. 3.--Revolving wheel, spaces fitted with colored
tissue paper.]
From another piece of cardboard cut out a wheel about 6 inches in
diameter, and of the shape shown in Fig. 3. The numerous spaces between
the spokes should be filled with pieces of transparent tissue paper of
various colors.
A small stand upon which this wheel can revolve is the next requisite.
This simply consists of a flat wooden base, with two wooden uprights
glued firmly upon it. These uprights are connected at one extremity by a
short piece of wire--an ordinary pin will serve the purpose
excellently--forming an axle for the cardboard to revolve upon. Fig. 3
makes this quite clear.
Now to test the effect of the first firework.
Fix the cardboard design in the upper portion of the frame, and stand
the whole upon a table. Then take a magic lantern (B, Fig. 4), or,
failing this, a bull’s-eye lantern or cycle lamp, and focus its rays
upon the cardboard design. Next place the “wheel” (C, Fig. 4) in such a
position that the beam of light shines through one of the tissue paper
films, and then continues its original course to the screen.
When everything is in position, the room in which the display is to take
place must be darkened. Having done this, grip the edge of the “wheel”
by the thumb and forefinger, and spin it sharply round.
[Illustration: FIG. 4.--Firework apparatus complete.]
As it swiftly revolves various colored beams of light will be thrown in
rapid succession on the cardboard screen, and, penetrating the minute
holes, will present the appearance of a fountain of brilliant,
life-endowed sparks.
THE FIREWORK BOXERS
But our firework show gives scope for far better effects even than this.
Some time ago great surprise was caused at an exhibition by the
production of a firework boxer. With a little care and ingenuity, the
same surprising result may be produced in the following manner:--
By means of a needle prick out two boxers in a defensive position (C and
D, Fig. 5). The others must then be designed; only in this case, one
boxer is administering the _coup de grace_ to his unfortunate opponent.
Two grooved strips of wood are next glued to the top and bottom, as
shown at A, Fig. 5, and two pieces of cardboard slid between them (B,
B). These two cards should then be connected by three pieces of wire, as
shown in the diagram, and have their corners rounded off in order to
insure free movement in the grooves.
By pulling the left wire one pair of figures is hidden and the other
revealed. Thus we have two firework boxers, who will fight a short but
decisive contest.
[Illustration: FIG. 5.--The firework boxers.]
There is another type of “indoor firework” working on the same principle
as the above. A reference to Fig. 6 will put the exhibitor in possession
of all its details.
[Illustration: FIG. 6.--Another type of indoor fireworks with changing
views.]
At first only the central “Catherine wheel” is seen by the audience.
Then, on the wire to the left being pulled, and the cardboard to which
it is attached raised, a fountain of fire shoots into the air and bursts
into a number of stars. A similar occurrence takes place on the right,
and by pulling the central wire the “Catherine wheel” is made suddenly
to vanish and give place to the spectacle depicted at D.
Care should be taken when manipulating these “mechanical” fireworks that
the hand does not come between the light and the framework.
Of course, on the above principles, numerous other designs may be made
for the show, and a stock of “fireworks” manufactured that will dwarf
any supply.