ROC′KETS. (In pyrotechny.) Prep. The CASES.—These are made of stout cartridge paper, rolled on a mould and pasted, and then throttled a little below the mouth, like the neck of a phial. The diameter should be exactly equal to that of a leaden ball of the same weight, and the length should be equal to 31⁄2 times the external diameter. Above the spindle there must be one interior diameter of composition driven solid. They are filled with the following mixtures, tightly driven in, and when intended for flight (SKY-ROCKETS), they are ‘garnished,’ and affixed to willow rods to direct their course.
The COMPOSITION.—1. (Marsh.)—a. For 2-oz. rockets. From nitre, 541⁄2 parts; sulphur, 18 parts; charcoal, 271⁄4 parts; all in fine powder, and passed through lawn.
b. For 4-oz. do. From nitre, 64 parts; sulphur, 16 parts; charcoal, 20 parts; as the last.
c. For 1⁄2-lb. to 1-lb. do. From nitre, 623⁄4 parts; sulphur, 153⁄4 parts; charcoal, 211⁄2 parts.
2. (Ruggieri.)—a. For rockets of 3⁄4-inch diameter. From nitre, 16 parts; charcoal, 7 parts; sulphur, 4 parts.
b. For 3⁄4- to 11⁄2-inch rockets, use 1 part more of nitre.
c. For 13⁄4-inch rockets, use 2 parts more of nitre.
d. By using 1 part less of charcoal and adding respectively 3, 4, and 5 parts of fine steel filings, the above are converted into ‘Brilliant fires,’
e. By the substitution of coarse cast-iron borings for filings, and a further omission of 2 parts of charcoal from each, the latter are converted into ‘Chinese fire,’
Hand-rockets and GROUND-ROCKETS are usually loaded with nothing but very fine meal gunpowder and iron or zinc filings or borings.