Pyrotechny. This is the art of making fireworks. The three principal materials employed in this art are charcoal, saltpetre, and sulphur, combined with filings of iron, steel, copper or zinc, or with resin, camphor, lycopodium and other substances, to impart color, or to modify the effect and duration of the combustion. Gunpowder is used, either in grain, half crushed, or meal (finely ground), as circumstances may require. Iron filings give red and bright spots. Copper filings give a greenish tint to flame; those of zinc, a fine blue color; sulphuret of antimony gives a less greenish blue than the zinc, but with much smoke; amber, resin and common salt afford a yellow lire. Lycopodium burns with a rose color and a magnificent flame, etc..

2049. The Leading Fireworks

2049.    The Leading Fireworks. The leading simple fireworks are rockets, Roman candles, flowerpots or gerbs, mines, and their adaptations or varieties; quick fires of different kinds and colors in cases, such as golden rain, spur fire, etc.; slow fires in cases and pots, as blue lights, Bengal lights, etc.. These form the fundamental principles of all pyrotechnic display. The endless variety of their combinations in the shape of vertical and horizontal wheels and "set pieces," requires considerable fertility of invention and mechanical ingenuity, combined with a thorough practical knowledge of the nature of firework compositions, and the appropriate means of displaying them to the best advantage. The weights used in the following receipts arc avoirdupois.

2050. To Make Plain Rockets

2050.    To Make Plain Rockets. The cases are made of stout cartridge paper, rolled on a rod whose thickness is equal to the desired diameter of the bore. The rod is slightly tapering, to allow of its easier withdrawal after the case is rolled and pasted. The narrower end of the case is choked; that is, a neck is made in it, similar to the neck of a phial. (See No. 2053 (To Choke Firework Cases),) The composition (see No. 2054 (Composition for Rockets)) is next rammed tightly into the case (see No. 2052 (To Charge Rocket Cases)), which is supported by a closely fitting mould during this operation, finishing with a small charge of gunpowder to explode when the rocket goes out. The top of the case is then stopped with clay and a conical cap fastened on, to decrease the resistance of the air in its upward flight; and the bottom or choked end of the case is furnished with priming and touch-paper. The whole is secured to the end of a willow stick, to direct its course through the air.

2051. To Make Display Rockets

2051. To Make Display Rockets. Rockets whose discharge ends in display, are furnished with an extra case, called the pot, about 1/3 the length of the rocket; its inside diameter is the same as the outside diameter of the rocket case, over which it is glued firmly, and takes the place of the conical cap. The garniture, consisting of stars, serpents, etc., as the case may be (see No. 2055 (Chinese Fire for Sky Rockets)), is inserted in the pot and connected with the charge in the rocket case by a quick match. (See No. 2060 (To Make Quick Match).) The whole is finished with the clay and cap, the same as the head of a simple rocket.