Jets of Fire.
4. Jets of Fire.
These are a kind of fixed Rocket, the effect of which is to throw up into the air Jets of Fire, similar in some respects to those produced by water. If a number of such Rockets be placed horizontally on the same line, it may be easily seen that the fire they emit, will nearly resemble a sheet of water, arranging itself in the form of a cascade. When the Rockets are arranged in a circular form, like the radii and periphery of a circle, they form what is termed a fixed Sun.
To procure these Jets of Fire, the cartridge for brilliant fires must in thickness be equal to a fourth part of the diameter, and for Chinese Fires only a sixth part of the same.
The cartridge must be loaded on a nipple, having a point equal in length to the same diameter, and in thickness equal to a fourth part of it; but, from the effect of the fire, the mouth generally becomes larger than is requisite; but this may be prevented, by charging the cartridge after the manner of the Chinese, who fill it to a height equal to a fourth part of the diameter with clay; this must be rammed down as if it were gunpowder.
When the charge is completed with the composition you have made choice of, the cartridge must be closed with a tompion of wood, above which it must be choaked.
The train or match must be of the same composition as that employed for loading; otherwise the dilatation of the air, contained in the hole made by the piercer, would cause the Jet to burst.
Clayed Rockets may be pierced with two holes near the neck, in order to have three Jets on the same plan.
If a kind of top, pierced with a number of holes, be added to them, they will nearly imitate a bubbling fountain.
Jets intended to represent sheets of fire, ought not to be choaked. They must be placed in a horizontal position, or inclined a little upwards or downwards.
If to the top of the cartridge be attached a tin cylindrical cap, terminating in a flat, long, narrow mouth, (similar to those attached to garden watering pots,) the stream of fire will be very much extended, and the beauty of the exhibition increased. The composition for this article is given in the table, section 7.