Sig′nal-rock′et.
Signal-rockets are composed of a
case, charged with composition; a
pot filled with
stars, gold-rain, or
serpents, and a stick.
They are named from the interior diameter of the case, as 3/4-inch, 1-inch, or 1 1/2-inch rockets.
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The case is formed of stout paper, which is cut into rectangles in width equal to the length of the case; these are rolled over a wooden former which is of the same diameter as that of the interior of the rocket, the paper is pasted after the first turn, and is drawn around the roller, keeping it perfectly taut as each turn is taken.
This is done on a flat table, and successive sheets of paper are added until the required thickness is attained.
It is then choked near one end by means of a stout cord wound once around it and drawn taut by means of a treadle, after which the choke is secured by several turns of twine, leaving an aperture large enough for the insertion of the spindle in driving; the case is now dried in the shade.
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Signal-light. |
When dry, the composition may be driven into the case.
For this purpose the choke end is cut off square to such a length that when the case is inserted in the mold, the choke shall fit closely over the nipple of the spindle, the end of the case resting on its base; being placed on the spindle, the case is driven firmly down, and the
mold placed over the case.
The mold is a metallic tube, bound with rings; or a block having a circular hole, into which the case fits, may be used for holding the case while driving.
For driving, three or more
drifts are used; these are of the same diameter as the rocket, but of different lengths, and all except the shortest are recessed to receive the spindle.
A ladleful of composition is poured into the case and driven down by 25 or 30 blows of a wooden mallet on the head of the drift, which is then withdrawn, and another ladleful of composition, poured in, which is similarly treated; the operation is proceeded with in this way, using the longest hollow drift first, and afterward the shorter ones successively until the top of the spindle is reached.
The case is then driven one diameter in hight with the solid drift, the composition covered with a paper wad cut to fit the case, over which is driven a wad of clay about 1/3 of a diameter in hight.
Cases may be driven without a
mold, being firmly fastened in an upright position.
The rocket is primed by a piece of quick-match, inserted in the choke-hole and coiled away at the bottom of the composition.
A cap of strong paper is then pasted over this end.
The
pot is a cylinder of rocket-paper, which is slipped over the case at the clay-wad end, projecting about 1 1/2 diameters beyond the end of the case; it contains the ornaments and a bursting charge of powder, and is pasted on to the case.
The
cone is made by a semicircular piece of thick paper wrapped around a conical wooden former and pasted.
This is secured over the end of the pot by a similar cone of thin paper, one inch longer, whose bottom is cut into slips and pasted to the pot.
The stick tapers gradually, being of .6 to .8 of an inch at the large, and .35 to .5 of an inch square at the small end. The large end is that attached to the rocket, and is tied on by means of twine or iron wire.
Its length is such that, when attached, the rocket should balance at from about 1 to 2 inches in rear of the case.
These dimensions apply for 3/4 to 1 1/2 inch rockets; for larger or smaller ones, they will be nearly in similar proportion to the size.
Marcus Graecus, who wrote about the close of the eighth century, gives the following directions: pulverize in a marble mortar 1 pound sulphur, 2 charcoal, and 6 of salter.; ram some of this powder tightly in a long narrow tube closed at one end, then set on fire, and the tube with fly through the air.
This is a veritable rocket.
Rockets from 3 to 4 inches in diameter ascend from 1,000 to 1,200 yards in from 7 to 10 seconds, and are visible 35 to 40 miles. Rockets of 1 or 2 inches diameter only ascend to from 450 to 600 yards.
