Page:Pyrotechnics the history and art of firework making (1922).djvu/178

 East. An interesting article appeared in the "Universal Magazine" of 1764, written by a Jesuit missionary on the subject of Chinese fireworks. In it he describes the making of iron sand as follows:

"Old broken or useless pots serve generally for making this sand; they are broken into pieces of the breadth of the hand, after which, being made red-hot in the fire of a forge, they are thrown in that condition into a trough filled with fresh water, where they are left to cool. Thus calcined, the rust falls off in scales, and they are easily reduced into sand, being first broken into parcels of a finger's breadth. The anvil and hammer used for this purpose must be also of cast-iron, because steel flats the grains of sand. It is necessary that the angles of those grains should be sharp, as it is the angles that form the flowers."

The word "gerb" is derived from the French word meaning a sheaf of corn, and was first applied to water fountains.

The flower pot is charged with a composition formerly known as "spur-fire," from the resemblance in form of its coruscations to the rowel of a spur. The effect produced is one of the most effective when successful, but has the disadvantage for display work that the effect is only appreciated at close quarters. The ingredients used are lampblack, sulphur, red arsenic, saltpetre, with sometimes the addition of charcoal and mealed gunpowder.

Of the smaller works of this division the squib and golden rain are too well known to need description. The squib and its variations have a choked case; the golden rain and similar works are left with an open bore.

Squibs are generally filled with a composition of sulphur, saltpetre and charcoal, sometimes steel filings, with a bounce of fine-grain powder,