Artificial fire-works

by Robert Jones

[Fig. 19], is a front view of the large rocket box. I, an iron plate, in which are holes of different sizes, through which the reammer passes; this plate is fastened with a screw in the center, so that when you change the reammer, you turn the plate round, but always let the hole you are going to use be at the bottom; the fronts of the other boxes must have holes in them to correspond with them in the plate. K, the lower part of the large box, which is made to fit the inside of the lathe, in order that all the boxes may move quite steady.

[Fig. 20], is a perspective view of the lathe. L, the guide for the reammer, which is set by the screw at bottom.

[Fig. 21], a view of the front of the guide facing the reammer. M, an iron plate, of the same dimensions as that on the front of the box, and placed in the same direction, and also to turn on a screw in the center. N, the rocket box, which slides backwards and forwards: when you have fixed a rocket in the box, push it forwards against the reammer; and when you think the scoop of the reammer is full, draw the box back, and knock out the composition; this you must do till the rocket is bored, or it will be in danger of taking fire; and if you bore in a hurry, wet the end of the reammer now and then with oil to keep it cool.

Having bored a number of rockets, you must have taps of different sorts according to the rockets. These taps are a little longer than the bore, but when you use them, mark them three diameters and a half from the point, allowing for the thickness of the rocket’s neck; then, holding the rocket in one hand, you tap it with the other. In order to explain these taps, I have represented one by [Fig. 22]. They are made in the same proportion as the fixed piercers, and are hollowed their whole length.

Of a Hand Machine used for boring of Rockets instead of a Lathe.

Those sort of machines answer very well, but not so expeditious as the lathe, nor are they so expensive to make; they may be worked by one man; but the lathe will require three. [Fig. 23], represents the machine. O, the rocket boxes, which are to be fixed and not to slide as those in the lathe. P Q, are guides for the reammers, that are made to slide together, as the reammer moves forward: the reammers for these sort of machines must be made of a proper length, allowing for the thickness of the front of the boxes, and the length of the mouth and neck of the case: on the square end of these reammers, must be a round shoulder of iron, to turn against the outside of the guide Q, by which means the guides are forced forwards. R, the stock which turns the reammer, and while turning must be pressed towards the rocket, by the body of the man who works it; all the reammers are to be made to fit one stock. This machine as well as the lathe is made by the scale in the same plate.

The Manner of making large Gerbes.

[Fig. 24], represents a wooden former; 25, a gerbe compleat, with its foot or stand. The cases for gerbes are made very strong, on account of the strength of the composition; which, when fired, comes out with great velocity; therefore, to prevent their bursting, the paper should be pasted, and the cases made as thick at the top as at the bottom; they ought also to have very long necks, for this reason; first, that the particles of iron will have more time to be heated, by meeting with greater resistance in getting out, than with a short neck, which would be burnt too wide before the charge be consumed, and spoil the effect: Secondly, that with long necks the stars will be thrown to a great height, and will not fall before they are spent, or spread too much; but, when made to perfection, will rise and spread in such a manner as to form exactly a wheat-sheaf.

In the ramming of gerbes, there will be no need of a mould, the cases being sufficiently strong to support themselves; but you are to be careful, before you begin to ram, to have a piece of wood made to fit in the neck; for if this be not done, the composition will fall into the neck, and leave a vacancy in the case, which, as I said before, will cause the case to burst as soon as the fire arrives at the vacancy: you must likewise observe, that the first ladle of charge, or two, if you think proper, be of some weak composition. When the case is filled, take out the piece of wood, and fill the neck with some slow charge. Gerbes are generally made about six diameters long, from the bottom to the top of the neck; their bore must be one fifth narrower at top than at bottom. The neck S is one sixth diameter and three fourths long. T, a wooden foot or stand, on which the gerbe is fixed. This may be made with a choak or cylinder, four or five inches long, to fit the inside of the case, or with a hole in it to put in the gerbe; both these methods will answer the same. Gerbes produce a most brilliant fire, and are very when a number of them are fixed in the front of a building, or a collection of fireworks.

N. B. Gerbes are made by their diameters, and their cases at bottom one fourth thick. The method of finding the interior diameter of a gerbe is thus: Supposing you would have the exterior diameter of the case, when made, to be five inches, then, by taking two fourths for the sides of the case, there will remain two inches and a half for the bore, which will be a very good size. These sort of gerbes ought to be rammed very hard.