52. _Coloured fires_, such as are employed for illuminating gardens,
shrubberies, avenues, buildings, &c., will now occupy our attention.
[Illustration:
Fig. 90.—Former for Coloured Fire Cases.
Fig. 91.—Iron Fork to support Coloured Fires while burning.
]
This species of firework is of very simple construction, and requires
only an ordinary amount of care in order to insure its success. And it
is very fortunate that so necessary an item in the programme of a
pyrotechnic display is one which can be relied upon for producing so
beautiful and surprising an effect. I have known spectators more pleased
with the coloured fires in an exhibition than with any other of its
features; and I am convinced, that by a well-contrived introduction and
arrangement of them, results may be produced at least as effective and
satisfactory as by any combination of a much more elaborate character.
But before entering upon the description of their manufacture, it will
be necessary for me to remind you of some information that I have
already given in the portion devoted to coloured stars, in order that
you may be induced not to prepare your colours for an exhibition until
you know _what you are going to prepare them for_—that is, what sort of
a place they are required to light up.
What I have before said under the head of Coloured _Stars_ with regard
to the illuminating or reflective properties of this or that
composition, must more than ever be borne in mind in the matter of
coloured _fires_. There are two kinds of fires used in pyrotechny—one
burning with a considerable depth and richness of tint, but possessing a
very moderate illuminating power, the other having great brilliancy and
reflective power, but not the same depth of colour. Now with this plain
distinction before us, there will be no difficulty in selecting such
composition as will produce the desired effect. You have simply to make
up your mind beforehand whether you require a colour of considerable
intensity, _which you may gaze at while it burns_, or one whose beauty
will be seen to advantage, _not in itself_, but in its reflection upon
those objects which are within reach of its illumination.
The formulas which I shall give will be characterised as “reflective,”
or “intense in colour,” and if they are only made up with pure, dry, and
fine ingredients, will, I am sure, give as good results as need be
desired.
In the first place the preparation of the cases is to be considered.
With regard to these it must be remembered that they are required _to
burn with the composition_, and must not be made too thick or hard on
that account. The thicker they are, the more will their consumption
interfere with the burning of, and impair the colour produced by, the
composition. A sheet of 60lb. or 70-lb. brown paper cut up into nine
strips in the manner represented at fig. 89 will furnish you some very
good cases for the purpose. Each of these strips will be a little over
three inches in width, which, in my opinion, is quite sufficient. The
former for these cases is made of wood, and should be from an inch and
a-half to an inch and three-quarters in diameter, and about four inches
long, irrespectively of its handle. The drift for filling the cases may
be of the same length, and _one-sixteenth of an inch smaller in
diameter_, so as to admit of its passing easily in and out of the case.
[Illustration:
Fig. 89.
]
The difficulty that I have always experienced with regard to these cases
has been this—they must be made of a certain thickness, in order that
they may not be broken during the process of ramming in the composition.
This process is, I believe, indispensable. At all events, I find it so,
for _if the composition be only pressed in loosely, and not rammed, it
will fall to the ground in burning lumps_, instead of burning slowly and
evenly in and with its case; and if the cases be made unnecessarily
thick, either the composition will not burn freely enough, or its colour
will be impaired (and this will be particularly the case with regard to
_green_ fires), or, what is more probable still, both these calamities
will happen at once, and render your production doubly ineffective.
Now my plan for obviating the difficulty has been to increase the
_diameter_ of the cases, and thereby to gain a greater body of
composition in proportion to their _thickness_. This plan I have found
to answer very well, and so I can conscientiously recommend it to you.
Take, then, one of the strips of paper, cut as recommended above, and,
pasting it all over on one side, roll it evenly round your former,
having previously brushed a little paste over the former to prevent the
paper sticking to it. Having rolled the strip up evenly and smoothly,
take it off from the former, and set it by to dry. It will readily be
perceived that these cases are among the easiest to make.
And now we may pass on to the important subject of the compositions with
which these cases are to be filled.