Page:Pyrotechnics the history and art of firework making (1922).djvu/175

 Early makers appear to have used mealed gunpowder and added charcoal and other ingredients to, as it were, dilute the powder and render the deflagration less fierce. Babington (1635) adds charcoal in the following proportion:

1 oz.—4 oz. rockets, 1 lb. of mealed powder to 2 oz. charcoal 4 oz.—10 oz. "     1 lb.      "       "      2-1/2 oz.   " 10 oz.—1 lb. "     1 lb.      "       "      3 oz.    "

John Bate's compositions are rather erratically arranged; in some cases he adds the saltpetre, charcoal, and sulphur, and a further addition is "yron scales," presumably to increase the effect of the tail, for which purpose later pyrotechnists used iron filings.

The rocket having been charged to the top of the heading, clay is charged in, forming a diaphragm above it. Earlier practice was to turn down the top edge of the case on the heading composition to form a diaphragm.

The best-known form of rocket is the sky rocket, which is fitted with a stick held in position by having a dowelled end introduced into a rolled paper or metal tube secured to the side of the rocket. The object of the stick is to direct the flight of the rocket, and further serves to hold it in position for firing, being passed through two rings at a suitable distance one above the other on a stake, through which it slides easily.

Sky rockets are fitted with a "cap" containing the "garniture" of the rocket, which may take the form of "stars" or other pyrotechnic effects, or a gun-cotton wad, or similar explosive to make a sound signal, or small cases charged with picrate of potash, producing the well-known "whistling rocket" effect.

The "cap" is either cylindrical or in the form of a truncated cone, with a conical or other top. The cap is burst open