PY'ROTECIINY, the art of making fireworks, is of unknown antiquity. It was prac ticed among the Chinese from the earliest times, and has attained with them a perfec tion unknown in other countries. So much is this the case, that they treat as insignifi cant the most brilliant of our European displays. In their fireworks they introduce many surprises, such as figures of men and animals darting out, but they are somewhat deficient in the mechanical arrangements. Fireworks, as the name is now understood, were hardly known in Europe until the discovery of the composition of gunpowder, and for a long time only very simple pyrotechnic contrivances were used. At present they may be divided into two kinds—the simple band-pieces, such as squibs, crackers, rockets, etc.; and the other, the fixed contrivances which have often very ingenious mechanical arrangements for making some of their parts revolve rapidly when being discharged. The materials used are gunpowder, sulphur, charcoal, saltpeter. filings of steel, iron, copper, etc., and several salts, such as nitrate of strontian, acetate of copper, common salt, etc. The ingredients of fireworks are usually filled into paper cases, made by rolling pasted paper round a cylinder of wood, of the proper diameter, until the case is of sufficient thickness, and then cutting the paper tube so formed into the required. lengths for squibs, Roman candles, small rockets, and similar articles; they seldom exceed ten inches: one end of each is closed by drawing a piece of string tightly round, so as, to pinch it in, or choke it, as it is technically called, and then dipping it into melted resin, which effectually seals it. The combustible ingredients are filled in at the open end, and, if necessary, are rammed down with a wooden ramrod; the opening is afterward covered with a piece of touch-paper, to prevent the composition falling out, and to ignite it by. The effects produced by fireworks are either streams of fire issuing straight out of the and much varied with sparks in the form of stars, etc., and colored with brilliant colors, or wheels of beautiful sparks produced by making the cases revolve rapidly. Revolving pieces are made by coiling the paper tube, when.not too tightly filled, around a flat wooden center; the force with which the combustion of the materials is carried on, is sufficient to make the board revolye with great rapidity. Small wheels of this kind are. called Catherine wheels. Squibs or serpents are made by filling tubes, eight to ten inches in length, with a composition of 1 lb. of niter, 2 oz. of charcoal powder (rather coarse), 4 oz. of gunpowder, 4 oz. of sulphur, and 6 oz. of steel filings. The last is an important ingredient in many fireworks, producing brilliant, feather-like coruscations, which are the more beautiful the larger and cleaner the filings are. Rockets are tied to a wooden
stick. When they are about to be discharged, this stick is stuck in the ground, and in that position the igniting point of the rocket is downward; when lighted, it rushes into the air with great velocity, and reaches a considerable height, discharging as it goes a brilliant stream of sparks. Rockets require a hollow center all down the tube; without this they will not rise. At the end of their course, they often discharge brilliant clusters of golden, ruby, emerald, sapphire-like stars, or showers of golden or colored rain, or of fiery serpents. This is produced by a supplementary part, called the garniture of the rocket, consisting of a shorter and broader paper tube, called the pot, attached to the "end of the fusee part of the rocket, and filled with a composition made into a paste with pure alcohol, and cut into stars, or granulated into small round bodies for drops. The serpents for rockets are small fusees, with the same composition as squibs; they are so packed in as to ignite all at once. The white stars are made of niter, 16 parts; sulphur, 8 parts; gunpowder, 3 or 4 parts; nitrate of strontian added, makes them ruby red; sul phate or acetate of copper, and sulphate and carbonate of barytes, green ; zinc filings give a blue color. Yellow stars and yellow showers are made of niter, 16 parts, 10 of sul phur, 4 of charcoal, 16 of gunpowder, and 2 of lamp-black. A deeper and richer golden color is produced by a very slight variation iu the composition—viz., 2 parts less of sul phur and charcoal, and 4 additional of gunpowder. Many other ingenious devices are used by masters in the art of pyrotechny, but they are too numerous and too technical to 'come within the limits of this work. The Boman candle is a favorite firework; it is a tube which is held on the ground, and discharges upward a continuous stream of blue or white stars or balls. Bengal lights are cases of about an inch or more iu diameter, filled with a composition of 7 parts niter, 2 of sulphur, and 1 of antimony. These are much used as signals at sea; they diffuse an immense glare of bluish-white light. Cleanse or jasmine fire, which is used by itself or in combination with other mixtures, consists of 16 parts of gunpowder, 8 of niter, 3 of finely-powdered charcoal, 3 of sul phur, and 10 of small cast-iron borings; the last must be finer or coarser in proportion to the bore of the case to be filled. The compound devices in fixed fireworks, such as are seen at public entertainments, are very complicated in their structure, and are varied more or less by every artist. One nice point in the arrangement is to insure simultaneous ignition of all the various parts.