PYROTECHNY, FIREWORKS. The composition of luminous devices with explosive combustibles, is a modern art, resulting from the discovery of gunpow der.
The three prime materials of this art are, nitre, sulphur, and charcoal, along with filings of iron, steel, copper, zinc, and resin, camphor, lycopodium, &c. Gunpowder is used either in grain, half crushed, or finely ground, for different purposes. The longer the iron filings, the brighter red and white sparks they give ; those being preferred which are made with a very coarse file, and quite free from rust. Steel filings and cast-iron borings contain carbon, and afford a more brilliant fire, with wavy radiations. Cop per filings give a greenish tint flame ; those of zinc, a fine blue color ; the sul phuret of antimony gives a less greenish blue than zinc, but with much smoke ; amber affords a yellow fire, as well as colophony, and common salt ; but the last must be very dry. Lampblack pro duces a very red color with gunpowder, and a pink with nitre in excess. It serves for making golden showers. The yellow sand or glistening mica, communicates to fireworks golden radiations. Verdi gris imparts a pale green ; sulphate of copper and sal-ammoniac, a palm-tree green. Camphor yields a very white flame and aromatic fumes, which mask the bad smell of other substances. Ben zoine and storax are used also on account of their agreeable odor. Lyeopodiuna burns with a rose color and a magnificent flame ; but it is principally employed in theatres to represent lightning, or to charge the torch of a fury.
Fireworks are divided into three classes : 1, those to be set off upon the ground ; 2, those which are shot up in to the air ; and 3, those which act upon or under water.
Composition for jets of ; the com mon preparation for rockets not more than 1 of an inch in diameter, is : gun powder, 16 parts ; charcoal, 3 parts. For those of larger diameter; gunpow der, 16 ; steel filings, 4.
Brilliant revolving wheel ; for a tube less than f of an inch ; gunpowder, 16 ; steel filings, 3. When more than / : gun powder, 16; filings, 4.
Chinese or Jasmine fire • when less than I of an inch: gunpowder, 16; nitre, 8; charcoal (fine), 3; sulphur, 3; pound ed cast-iron borings (small), 10. When wider than gunpowder, 16 ; and nitre, 12; charcoal, 3; sulphur, 3; coarse bor ings, 12.
A fixed brilliant; less than in diame ter : gunpowder, 16 ; steel filings, 4 ; or, gunpowder, 16 ; and finely pounded bor ings, 6.
.Fixed suns are composed of a certain number of jets of fire distributed circu larly, like the spokes of a wheel. All the fusees take fire at once through chan nels charged with quick matches. Glories are large suns with several rows of fusees. Fans are portions of a sun, being sectors of a circle. The Patte d'oie is a fan with only three jets.
&acacia imitate sheets or jets of water. The Chinese fire is best adapted to such decorations.
Fixed stars. The bottom of a rocket is to be stuffed with clay, and one diameter in height of the first preparation being introduced, the vacant space is to be filled with the following composition, and the mouth tied up. The pasteboard must be pierced into the preparation, with five holes, for the escape of the luminous rays, which represent a star.
Composition offixed stars :— Ordinary. Brighter. Colored.
Nitre 16 i2 0 Sulphur 4 6 6 Gunpowder meal 4 12 16 Antimony 2 1 2 Lances are long rockets of small diam eter, made with cartridge paper. Those which burn quickest should be the long est. They are charged by hand without any mould, with rods of different lengths, and are not strangled at the mouth, but merely stuffed with a quick match of tow. These lances form the figures of great decorations ; they are fixed with springs upon large wooden frameworks, representing temples, palaces, pagodas, &c. The whole are placed in communica tion by conduits, or srna'l paper cartrid ges, like the lances, but somewhat coni cal, that they may fit endwise into one another to any extent that may be desir ed. Each is furnished with a match thread fully 11 inches long, at its two ends.