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Twinklers are stars which, when they fall through the air, burn brightly and dully by turns. A shower of twinklers produces an extraordinary effect. Weingart in a recent letter has kindly sent the following formula for yellow twinklers:

Meal powder 24

Sodium oxalate 4

Antimony sulfide 3

Powdered aluminum 3

Dextrin 1

The materials are mixed intimately while dampened with water, and the mixture is pumped into stars about % inch in diameter and 7/s inch long. The stars are dried promptly. They function only when falling through the air. If lighted on the ground they merely smolder, but when fired from rockets or shells are most effective.

Spreader stars contain nearly two-thirds of their weight of powdered zinc. The remaining one-third consists of material necessary to maintain an active combustion. When they are ignited, these stars burn brightly and throw off masses of burning zinc (greenish white flame) often to a distance of several feet. Weingart gives the two following formulas for spreader stars, the first for "electric spreader stars," the second for "granite stars," so called because of their appearance.

Zinc dust 72 80

Potassium nitrate 28

Potassium chlorate 15

Potassium dichromate 12

Granulated charcoal 12

Fine charcoal 14

Sulfur 5

Dextrin 2 2

The first of these formulas is the more difficult to mix and the more expensive. All its components except the charcoal are first mixed and dampened; the granulated charcoal, which must be free from dust, is then mixed in, and the stars are formed with

Figure 30. Spreader Stars from a Battery of Rockets.

a pump. They throw off two kinds of fire when they burn, masses of brightly burning zinc and particles of glowing charcoal. Wein-

gart recommends that the second formula be made into cut stars

% inch on the side. Spreader stars because of the zinc which they contain are much heavier than other stars. Rockets and aerial bombs cannot carry as many of them. Gerbs

Gerbs produce jets of ornamental and brilliant fire and are used in set pieces. They are rammed or pressed like rockets, on a short nipple instead of a long spindle, and have only a slight depression within the choke, not a long central cavity. They are choked to about one-third the diameter of the tube. The simplest gerbs contain only a modified black powder mixture, say meal powder 4 parts, saltpeter 2, sulfur 1, and charcoal dust 1 or mixed charcoal 2; and are used occasionally for contrast in elaborate set pieces. Similar composition is used for the starting fire of steel gerbs which are more difficult to ignite. If antimony sulfide is used in place of charcoal, as in the mixtures:

Meal powder 2 3

Saltpeter 8 8

Sulfur 3 4

Antimony sulfide 1 ?

the gerbs yield compact whitish flames and are used in star and floral designs. Gold gerbs appropriately arranged produce the sunburst effect. Colored gerbs are made by adding small cut stars. In loading the tube, a scoopful of composition is introduced

Meal powder Potassium nitrate

Sulfur

Fine charcoal----

Steel filings

Stars

Sodium oxalate. . Antimony sulfide.

Aluminum

Dextrin

Steel

Colored Steel

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