Of the SPUR-FIRE.
This fire is the most beautiful and curious of any yet known, and was
invented by the Chinese, but now is in greater perfection in England,
than in China; and as it requires a great deal of trouble to make it
to perfection, it will be necessary that young beginners should have
full instructions in every particular; therefore care ought to be
taken that all the ingredients be of the best sort, that the
lamp-black is not damp and clodded, and that the saltpetre and
brimstone are thoroughly refined. This composition is generally rammed
in one or two ounce cases, about five or six inches long, but not
drove very hard; and these cases must have their concave stroke struck
very smooth, and the choak or vent not quite so large as the usual
proportion; this charge, when driven and kept a few months, will be
much better than when just rammed, but will not spoil, if kept dry, in
many years.
Now as the beauty of this composition cannot be seen at so great a
distance as brilliant fire, it has a better effect in a room than in
the open air, and may be fired in a chamber without any danger; for it
is of so innocent a nature, that, though with an improper phrase, It
may be called a cold fire; and so extraordinary is the fire produced
from this composition, that, if well made, the sparks will not burn a
handkerchief, when held in the midst of them; you may hold them in
your hand while burning, with as much safety as a candle; and if you
put your hand within a foot of the mouth of the case, you will feel
the sparks like drops of rain. When any of these spur-fires are fired
singly, they are called artificial flower pots; but some of them
placed round a transparent pyramid of paper, and fired in a large
room, make a very pretty appearance.
The Composition for the SPUR-FIRE.
Saltpetre four pound eight ounces, sulphur two pound, and lamp-black
one pound eight ounces.
Or, saltpetre one pound, sulphur half a pound, and lamp-black four
quarts.
As the spur-fire composition is very difficult to mix, and the manner
of doing it quite different from any other, I shall here treat of it
separately; for example, the saltpetre and the brimstone must be first
sifted together, and then put into a marble mortar, and the lamp-black
with them, which you work down by degrees, with a wooden pestle, till
all the ingredients appear of one colour, which will be something
greyish, but very near black; then drive a little into a case for
tryal, and fire it in a dark place; and if the sparks, which are
called stars, or pinks, come out in clusters, and afterwards spread
well without any other sparks, it is a sign of its being good,
otherwise not; for if any drossy sparks appear, and the stars not
full, it is then not mixed enough; but if the pinks are very small,
and soon break, it is a sign that you have rubbed it too much.
N. B. This mixture, when rubbed too much, will be too fierce, and
hardly shew any stars at all; and, on the contrary, when not mixed
enough, will be too weak, and throw forth an obscure smoke, and lumps
of dross, without any stars. The reason of this charge being called
the spur-fire, is because the sparks it yields have a great
resemblance to the rowel of a spur, from whence it takes it’s name.
Characters, or significant Signs, for distinguishing
the different Ingredients used in Fireworks.
Meal Powder M
Corned Powder Э
Saltpetre Θ
Brimstone Z
Crude Sulphur C Z
Charcoal C +
Sea Coal C S
Saw-dust or Beech-raspings B R
Steel or Iron-filings S x
Brass-dust B x
Glass-dust G x
Tanners-dust of Bark T x
Cast Iron C I
Antimony Crude C A
Camphor x
Yellow Amber A Y
Lapis Calaminaris L S
Gum ∩.
Lamp Black B L
Isinglass G I
Spirit of Wine W
Spirits of Turpentine S T
Oil of Spike P O
The use of the above characters is, that by the help of them, the
different receipts may be contracted to so small a compass, that they
may all be contained in one leaf of a pocket book, which is much less
than any table that has yet been invented. These signs are also very
convenient for those who travel.
How to meal GUN-POWDER, BRIMSTONE, and CHARCOAL.
There have been many methods used to grind these ingredients to a
powder for fireworks, such as large mortars and pestles, made of
ebony, and other hard wood; likewise horizontal mills with brass
barrels; but none of these methods has proved so effectual and speedy
as the last invention, that of the mealing table, which is represented
in Plate 1. Fig. 1. This table it made of elm, with a rim round it’s
edge, four or five inches high; and at the narrow end, A, is a slider,
which runs in a groove and forms part of the rim; so that when you
have taken out of the table, as much powder as you conveniently can,
with the copper shovel Fig. 2. you may sweep all clean out at the
slider A. When you are going to meal a quantity of powder, observe not
to put too much in the table at once; but when you have put in a good
proportion, take the muller Fig. 3. and rub it therewith till all the
grains are broke, then fearce it, in a lawn sieve that has a receiver
and top to it; and that which does not pass through the sieve, return
again to the table and grind it more, till you have brought it all
fine enough to go through the sieve. Brimstone and charcoal are ground
in the same manner as gun-powder, only the muller must be made of
ebony, for these ingredients being harder than powder, would stick in
the grain of elm, and be very difficult to grind; and as the brimstone
is apt to stick and clod to the table, it would be best to keep one
for that purpose only, by which means you will always have your
brimstone clean and well ground.
To prepare CAST-IRON for Gerbes, White Fountains, and Chinese Fire.
Cast-iron being of so hard a nature, as not to be cut by a file, we
are obliged to make use of the following method to reduce it into
grains, though somewhat difficult to perform; but if we consider what
beautiful sparks this sort of iron yields, no pains should be spared
to granulate such an essential material, to do which you must proceed
thus: get at an iron foundry some thin pieces of iron, such as
generally runs over the moulds, at the time of casting: then have a
square block made of cast iron, and a square hammer of the same metal,
about four pound weight; then, having covered the floor with cloth, or
something to catch the beatings, lay the thin pieces of iron on the
block, and beat them thereon with the hammer, till you have reduced
them into small grains, which afterwards searce with a very fine
sieve, in order to separate from them the fine dust, which is
sometimes used in small cases of brilliant fire, instead of steel
dust; and when you have got out all the dust, sift what remains with a
sieve a little larger, and so on with sieves of different sizes, till
the iron will pass through about the bigness of small bird shot: your
iron being thus beat and sifted, put each sort into wooden boxes or
oiled paper, to keep it from getting rust. When you use any of this
iron, observe that you make a difference in its size, in proportion to
the cases for which the charge is intended; for the coarse sort
of it is only designed for very large gerbes, of six or eight pound
weight.
Charges for Sky-Rockets, &c.
For Rockets of Four Ounces.
Mealed powder one pound four ounces, saltpetre four ounces, and
charcoal two ounces.
For Rockets of Eight Ounces.
I. Meal powder one pound, saltpetre four ounces, brimstone three
ounces, and charcoal one ounce and a half.
II. Meal powder one pound and a half, and charcoal four ounces and a
quarter.
For Rockets of One Pound.
Meal powder two pound, saltpetre eight ounces, brimstone four ounces,
charcoal two ounces, and steel filings one ounce and a half.
For Sky Rockets in general.
I. Saltpetre four pound, brimstone one pound, and charcoal one pound
and a half.
II. Saltpetre four pound, brimstone one pound and a half, charcoal one
pound twelve ounces, and meal powder two ounces.
For large Sky Rockets.
Saltpetre four pound, meal powder one pound, and brimstone one pound.
The following Compositions may be used for Rockets of
a middling size.
I. Saltpetre eight pound, sulphur three pound, meal powder three
pound.
II. Saltpetre three pound, sulphur two pound, meal powder one pound,
charcoal one pound.
Compositions for Rocket Stars.
For White Stars.
Meal powder four ounces, saltpetre twelve ounces, sulphur vivum six
ounces, oil of spike two ounces, and camphor five ounces.
For Blue Stars.
Meal powder eight ounces, saltpetre four, sulphur two, spirits of wine
two, and oil of spike two.
Coloured, or variegated Stars.
Meal powder eight drams, rochpetre four ounces, sulphur vivum two
ounces, and camphor two ounces.
For Brilliant Stars.
Saltpetre three ounces and a half, sulphur an ounce and a half, and
meal powder three quarters of an ounce. This composition must be
worked up with spirits of wine only.
For Common Stars.
Saltpetre one pound, brimstone four ounces, antimony four ounces and
three quarters, isinglass half an ounce, camphor half an ounce, and
spirits of wine three quarters of an ounce.
For Tailed Stars.
Meal powder three ounces, brimstone two ounces, saltpetre one ounce,
and charcoal (coarsely ground) three quarters of an ounce.
For Drove Stars.
I. Saltpetre three pound, sulphur one pound, brass dust twelve ounces,
and antimony three ounces.