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

by G. W. Mortimer

The length of this former, or roller, is not particular, providing it be long enough to admit of good hand-hold in the rolling of the cases; the short part of the former A may be two diameters in length, and should have a line B marked round it in the middle, or one diameter from the end; the longer part may be seven or eight diameters, which will give good hand-hold in the rolling.

[Fig. 4 and 5], are rammers, or drift pins, used in loading the cases, which must be pierced lengthwise to fit on to the piercer.

[Fig. 4]. The first rammer should be pierced the whole length of the piercer, the second rammer should be pierced one and a half diameter; when the case is loaded and rammed above the piercer, a short solid rammer must be used, and these rammers should be a little less than the former, to prevent injury to the inside of the cartridge, when driving in the charge. They should be made of some hard wood, and their extremities secured by ferrels of brass, or any other metal, which will keep them from splitting or extending: their lengths are of little consequence, providing they do not much exceed the relative depths of the cartridge; for, as the workmen say, the longer the rammer the less will be the pressure on the composition by the blow given by the mallet.

The proportion between the length of Rockets and their calibre, is not the same in Rockets of greater or less dimensions than those given above, but should vary nearly as their magnitude; that is to say, their length should be diminished as their calibre is increased. The length of the mould for small Rockets should be six times the calibre, but for Rockets of the mean and larger size, it will be sufficient if the length of the mould be five times, or even four times that of the calibre.

The following is a table computed to regulate the height and diameter of the mould according to the weight of the Rockets, when they are driven solid, or without the use of a piercer. It is extracted from an old treatise on fire-works by Lieutenant Robert Jones; and inserted for the assistance of those who may wish to construct Rockets without the piercer, a practice we would never recommend to those for whom our “Manual” is designed. To those who manufacture fire-works for sale it is certainly the most expeditious method to ram them solid, and with the machine to bore or pierce them afterwards; but to those who make Rockets for their own private recreation, it is by far the most eligible to load them over a piercer, for by the other method it will require a very expensive apparatus,[9] and at first more skill to use it than what the Tyro will possess, and at last he will never be certain that he has made a good article.

Dimensions of Rockets.

TABLE I.

Dimensions of Rockets.