The Chemistry of Powder and Explosives - Sciencemadness Dot Org

112 PYROTECHNICS
tion 4 parts potassium nitrate, 1 of charcoal, and 1 of sulfur has
been reported in Chinese firecrackers; more recently mixtures
containing both potassium nitrate and a small amount of potassium
chlorate have been used; and at present, when the importation
of firecrackers over 1% inches in length is practically 51 prohibited,
flash powders containing aluminum and potassium
FIGURE 37. Chinese Firecracker-*. Tying the Tubes into Bundles. (Courtesy
Wallace Clark.)
chlorate are commonly used, for they give a sharper explosion
than black powder.
The Chinese firecracker industry formerly centered in Canton
but, since the Japanese occupation, has moved elsewhere, largely
to French Indo-China and Macao in Portuguese territory. Its
processes require great skill and manual dexterity, and have
long been a secret and a mystery to Europeans. So far as we
know, they had not been described in English print until Weingart's
book 32 published an account of the manufacture of clayplugged
crackers based upon information received from the
manager of a fireworks company at Hong Kong. His account is
illustrated with three pen sketches, two of them of workmen
51 Firecrackers not exceeding 1% inches in length and 5/16 inch in diameter
carry a duty of 8 cents per pound. For longer crackers the duty is
25 cents per pound, which practically prohibits their importation.
52 Op. cit., pp. 166-170.