A Manual of Pyrotechny; or, A Familiar System of Recreative Fire-works

by G. W. Mortimer

7. Rockets must be rammed with mallets somewhat proportionate to their magnitude; that is, if a Rocket of one pound can be properly rammed with a mallet weighing two pounds, a Rocket of two pounds should be rammed with a mallet of four pounds, or nearly in that proportion. Rockets above eight pounds cannot well be rammed by hand; but when wanted of such magnitude they must be rammed by means of a machine similar to that used for driving piles into the earth; Rockets of large dimensions, whose cases are made of a strong material, properly prepared, may be conveniently rammed without being placed in a cylinder, which will be an advantage, as so many moulds will not be required. But for this method of ramming we must be prepared with some brass or iron nipples, of the size proportionate to the Rocket, which should be made to screw into one part of the driving block; and for the purpose of making the case more firm upon it while ramming, a stake or upright piece must be made firm to the block, standing up the height of the case, and at a suitable distance from the nipple; the side of this stake next the case must be fluted out so that the case will fit closely into it; on the opposite side of the case must be applied a loose piece fluted in a similar manner; then with a cord tie the case and two half moulds (which these two pieces will nearly form) together, and the case will be ready for filling. The cartridges being filled to the proper height, i. e. one diameter above the piercer, if the Rocket is to be without furniture, separate with a wire of any kind, half the folds of the paper which remains above, and having turned them back on the composition, press them down with the rod and mallet in order to make them smooth and even. Then pierce three or four holes in the folded paper by means of a piercer, which must be made to penetrate to the composition of the Rocket. These holes are for the purpose of forming a communication between the body of the Rocket and the vacuity at the extremity of the carriage, as it is called, or that part which has been left empty. In small Rockets this vacuity is filled with granulated powder, (which serves to let them off when their charge is consumed;) they are then covered with paper, and either pinched quite close by means of the choaking apparatus, or crowned with a little conical cap, which will cause it to ascend to a greater height. If one hole only is made in the centre of the folded paper, it will answer the purpose of three or four, taking care that it be as straight as possible, and about one-fourth the diameter of the calibre of the case; in this hole a little of the composition of the rocket should be put that the fire may not fail to be communicated:—a Rocket finished after this manner is represented in [fig. 23]. In Rockets of larger dimensions, instead of granulated powder, the coffins, or pot containing the stars, serpents, petards, &c. are adapted to the top of the case: the petard is a small round box of tin-plate united to the diameter of the case, and filled with fine gunpowder; it is deposited on the composition after the ramming, and the remaining paper folded down over it to keep it secure; the petard produces its effect when the Rocket is in the air and the composition is consumed. The other furniture is attached to the Rocket by adjusting to its head an empty pot or cartridge of larger dimensions than itself, in order that it may contain the various appendages, which are to render it so superior to the others, in the beauty and splendour of its emication.

Preparing and fixing the pots to the head of Rockets.

Preparing and fixing the pots to the head of Rockets.—Rockets which have furniture attached to them, are rammed somewhat different to those which are without any appendages, but the difference is only in this particular; when rammed one diameter above the piercer, instead of turning down upon the composition the inner folds of the paper, ram on to the composition one-third diameter of pure dry clay, and through the centre of it bore a hole (about one fourth diameter) and put into it a little of the composition, in order that the charge may communicate with the powder, &c. in the head.

The head of a Rocket must be about two diameters high, and one diameter one-sixth wide. The case must be rolled upon a former, having at the end opposite the handle a square indent, corresponding to the thickness and width of the collar, as is represented in [fig. 9. Fig. 10] is the collar, turned out of lime-tree, poplar, or any light wood; its exterior diameter must be equal to the interior diameter of the case, or the same as the former, and its interior diameter, not quite so wide as the interior diameter of the Rocket case; in thickness it should be equal to one-sixth diameter, and round its edge should be a groove, so that the case for the head may be firmly fixed to it. To form the case, three or four rounds of paper or pasteboard must be rolled round the former, with the collar on, and well secured by paste; the end over the collar is to be pinched by means of the cord and choaking apparatus into the groove in its edge, and afterwards secured by some twine tied closely round it. The purpose of the collar is to keep the head in a proper form, to make a bottom for the filling of it, and to make it more firm and better connected to the case. When the head is thus made, being properly fixed to its collar, it is to be made fast (by means of ordinary glue) to the top end of the Rocket, in which operation the reason and use of making the interior diameter of the collar less than the exterior of the cartridge will plainly appear; it will be evident that the cartridge of the Rocket will be too large for the former, without some alteration, which alteration must be made in the following manner:—mark round the diameter of the Rocket the proper distance from the top, or so that the collar is about its thickness above the ramming of the cartridge, and take off about three rounds of paper, which will leave a shoulder to the case, on which the collar may rest, and be made quite secure by pasting paper round their joinings beneath.

In the manner of charging the pot above described we must almost leave the Tyro to himself, it depending chiefly on his taste and wishes, as he may either fill it with Serpents, Crackers, Saucissons, Marroons, Stars, Sparks, Showers of Fire, or any thing to which its capacity is adapted; it will be best however to unite several of the different articles in one head that the beauty of the exhibition may be increased.

In the filling of the head, the following directions must be observed:—

The paper over the charge of the Rocket must be pierced, and a little of the same composition shook into the holes; then arrange in the head the different articles with which it is to be charged, but take particular care that the quantity introduced is not heavier than the body of the Rocket. When the head is loaded, a few balls of paper should be put round the different articles so as to keep them properly in their places. At the top part of each head put a ladle full of meal powder, (the ladle you use in filling the cases is meant,) which will be enough to burst the head and disperse the stars or whatever it contains.

In loading the head with cases of any kind be sure to place their mouths downward without any touch-paper; the head may be nearly filled, with the articles they are loaded with, after which paste on the top of them a piece of ordinary paper; and over this must be placed a cone of the same material, made upon the conical former, [fig. 8]. To make the caps, describe (with a pair of compasses opened to the length of the former) a circle, which being divided into two equal parts, will make two caps; over which must be pasted another similar cap, but of larger dimensions, so that it extend below the bottom of the inner one; so that being just clipped a little and applied to the head, it may be pasted to it, which will be a sufficient fastening.

Table for the Length and Proportion of Rods.

The last business in the manufacturing of a Rocket is that of fixing it to its rod, which we shall now describe, as much nicety being required in it as in any of the past operations.