No. 21.
Nitrate of baryta 80 parts.
Chlorate of potash 32 „
Sulphur 24 „
Calomel 16 „
Charcoal (fine) 3 „
Shellac 2 „
The drawback to all green colours burnt in cases is that the combustion
of the case itself impairs to some extent the purity of the tint of the
flame. Cases, therefore, which are to contain green fire must not be
made unnecessarily thick. Composition No. 21 gives by far the best
colour that I have yet seen for this purpose, and when contrasted with a
good red is all that one need desire.
The two next compositions will furnish exceedingly beautiful red
colours. It is best to make them up only a short time before using them,
as their effect is much more brilliant when quite freshly mixed; and,
besides, the nitrate of strontia becomes damp after a time, particularly
in the autumn and winter months, in which case it will produce only the
effect of disappointing you. The compositions are both perfectly safe,
since they contain no sulphur, and are on that account entirely free
from all liability to spontaneous combustion:—
_Red Lights._
No. 22.
Chlorate of potash 32 parts.
Nitrate of strontia 48 „
Calomel 20 „
Shellac 12 „
Chertier’s copper 4 „
Charcoal (fine) 1 part.
Or,
No. 23.
Chlorate of potash 84 parts.
Nitrate of strontia 80 „
Calomel 51 „
Dextrine 22 „
Shellac 18 „
Chertier’s copper 4 „
Of these two formulæ, No. 22 is the one that I generally employ. It
produces a very brilliant colour, which is _almost scarlet_, and forms,
in my opinion, the best contrast both to the green and purple lights.
No. 23 gives a deep rich crimson, which may also be found very effective
occasionally. Dextrine, which enters into its composition, is always to
be had in very fine powder, and therefore it will give you no trouble to
bring it into the proper condition for use. It is very cheap, being sold
generally at from 1s. to 1s. 6d. per pound. You will require only a very
small quantity of it.
We now come to the last of our colours for making these decorating
lights, and that is the purple.
_Purple._
No. 24.
Chlorate of potash. 28 parts.
Chertier’s copper 28 „
Calomel 13 „
Shellac 8 „
Stearine 1 part.
Or,
No. 25.
Chlorate of potash 40 parts.
Calomel 28 „
Chertier’s copper 28 „
Dextrine 10 „
Stearine 3 „
No. 26.
Chlorate of potash 26 „
Chertier’s copper 24 „
Calomel 14 „
Shellac 7 „
All of these three formulæ produce good colours. I think that I am
rather inclined to give the preference to No. 25, on account of the very
effective contrast that it makes when employed to burn with the red at
No. 22. These three colours are perfectly safe, for the same reason that
I stated above when speaking of the red lights.
I trust that the formulæ which I have now given will be found to supply
all that you will require in this department of pyrotechny. The
compositions have all been used by me, and I can therefore speak from
actual experience of their respective merits, and so you will be pleased
to remember that if they do not succeed in your hands the fault will lie
either in the condition, perhaps the impurity, of your chemicals, or in
your own manipulation. I can answer for the receipts; all that is
necessary on your part is a scrupulous attention to my directions.
And here let me put in a word of caution. Where you see “_Red Lights,
Green Lights, Purple Lights_” written over the formulæ above, you are to
remember distinctly that I use the word “LIGHTS” to distinguish this
branch of pyrotechny, and these compositions, from those which I mean to
treat of under the title of coloured “FIRES.” By coloured lights I mean
small cases, of the 1 or 2-oz. size, filled with either of the above
compositions from No. 19 to No. 26 inclusive. _These compositions are
not adapted for the purpose of producing coloured FIRES, such as are
employed to light up gardens, avenues, buildings, &c._ They are to be
confined to their own use, which is _the decoration of wheels, or of any
large and complicated exhibition fireworks_. For this purpose they
_will_ answer _well_, and for the other _they will not answer at all_.
And having now explained the distinction between coloured LIGHTS and
FIRES, I must ask my readers not to lay the blame upon me if, when
employing my compositions for purposes for which they were never
intended, they find they do not succeed.
[Illustration:
Fig. 74.
]
But we have still to speak of the way in which these coloured lights are
to be fastened to the pieces which they are designed to decorate. The
most common way of doing this is to drive a nail into the wooden
framework of the piece at the place where you wish to place the coloured
light, and to tie the case which contains it to this nail. Two nails,
like “two heads,” are better than one, and the case may be secured as
shown in the annexed sketch (fig. 74). A represents the coloured light
case; B the string which is passed round its lower clayed end, by means
of which it is secured to the two nails, C C, which are driven into the
wooden framework. This mode of fastening is very simple and effective
for attaching the coloured fire cases to the framework of a _fixed_
piece. But in the case of a wheel, or any piece which has motion, it is,
in my opinion, very desirable to give them a position like that of the
_wheel-cases_—_i.e._, to let them revolve with their mouths in the
opposite direction to that of the motion of the wheel. This is easily
done, either by fastening them between the spokes of a large wheel, or,
in the case of a small one, by driving in a longer nail than is
necessary, and bending down the head of it in the desired direction, and
fastening the coloured light case to this bent part (fig. 75).
[Illustration:
Fig. 75.
]
By this means you will have no difficulty in attaching these little
decorations in any place, to any part of the framework of your piece, or
in any direction. The object of turning the mouth away from the
direction in which the piece moves is that the resistance offered by the
air during its revolution may not interfere with the easy combustion of
the coloured light.
But we have yet to say a few words about the filling these 1 or 2-oz.
cases, and their priming.
The compositions used for this purpose do not require, it must be
remembered, to be _rammed_ into the cases; they only need be _pressed
in_ so firmly that their motion during combustion shall not shake them
out. Of course they should be _uniformly_ pressed in, and this is simply
done by pressing in only a small quantity at a time.
With regard to their priming, this may be done in either of the
following ways—by smearing into their mouths some wetted meal-powder,
or, what is better, by pressing into their mouths a piece of
quick-match, and then pressing a little of the coloured composition over
that, and allowing the end of the match to project about half-an-inch.
But in whatever way they are primed they must have two rounds of some
thin paper pasted round their mouths, and projecting an inch or so
beyond them, into which the leaders can be tied which are to connect
them with the other cases of the piece.
In the case of small wheels, in which only one of these coloured light
cases is to be employed, it will be advisable to fill it with
compositions of different colours. Press in first enough red-light
composition to fill one-third of the case; then enough purple to occupy
another third, and fill the remainder of the case with green
composition. By this means you will be able to vary your effects to any
extent.
I now wish to give you directions for making a very beautiful and
effective firework, in which these coloured lights play a prominent
part. I must refer you to the page of illustrations which accompanies
this paper, in order that you may have no difficulty in understanding
the directions which I am now about to offer.
In its general working the piece is very similar to that which I have
described under the name of “Brilliant Wheel” at paragraph 43. But it is
at the same time a great improvement upon the one there spoken of. Cut a
piece of deal or beech board into the shape drawn at _A A_. (fig. 76).
This should be at least half-an-inch in thickness, and not less than
three feet in length. When you have shaped it as you intend to leave it,
find its centre, the point at which it balances. Through this point bore
a hole of such a size as will easily admit the iron spindle which screws
into your firework post (fig. 70). At each end of this wooden frame
place three wheel-cases, taking care that the position of the mouths of
these cases is so arranged that their driving power shall all be in one
direction. A quick-match leader is to be carried from the _tail of the
extreme case at each end to the mouth of the next_, and then from the
tail of these to the mouths of the third at each end.
Two more pieces of wood (represented at _B B_. fig. 76) will now be
required, each about twelve inches long, five-eighths of an inch wide,
and three-eighths of an inch thick. They must have a hole bored through
them, into which a spindle or smooth round nail can pass easily. _But
this hole must not be in their centre_; it should be bored about four
inches from one end, which will leave eight inches on the other side of
the hole. Through these holes drive a smooth round nail into the long
framework of the piece, exactly half-way between its centre and the
innermost wheel-cases. The object of hanging these two pieces _not_ by
their centre of balance is that one end being longer, and therefore
heavier, than the other, may cause the pieces to fall round by their own
weight, as the firework makes its revolutions. To these two pieces
coloured lights are attached at each end in such a position that they
shall project horizontally at right angles with the pieces _B B_. This
will be seen clearly by reference to the drawing at _C C_. (fig. 77),
which is intended to give you a side view of the same piece. It must not
be forgotten that the satisfactory performance of this firework depends
mainly upon the exactness and true adjustment of the woodwork. Unless
the revolving pieces are neatly hung, and the balance of the main
framework is true, you must not expect success.
The coloured lights may be arranged as follows:—A green and a red light
on one of the revolving pieces, and a purple and red on the other. These
coloured lights are all to be connected together and with the mouths of
the two extreme wheel-cases by quick-match. It will be obvious, then,
that the coloured lights must be so prepared as to last during the
combustion of the three driving cases.
The drawing at (fig. 78) represents a rather better position for the
wheel-cases than that given at (fig. 76).
The diagram (fig. 79) represents a wheel frame, to which are attached at
_f f f_ coloured lights. The position there indicated is a very good one
for coloured lights when required for wheels of any such make as that in
the drawing. You must not forget that they are all to be placed at
_different distances from the centre of the wheel_. They may, of course,
be made to play their part at any period of the wheel’s revolution. The
coloured lights, for whose manufacture I have given directions above,
are very valuable auxiliaries in nearly all exhibition pieces, and that
we shall have occasion to call them in frequently to our aid as our
practical pyrotechny becomes more advanced, and our enthusiasm in the
art leads us to search for new combinations and effects.