In charging cases of half an inch caliber, fifteen blows with the mallet must be given; for three-quarters of an inch, twenty blows; for one inch, twenty-five blows; for one and a quarter inches, thirty blows; one and a half inches, thirty-five blows; for two inches, forty blows; and for three inches, fifty blows;—that is to say, the number of blows must be given to each charge put in, which ought to occupy half the interior diameter of the case. The rammer must be frequently taken out, and struck, so as to disengage any of the composition, which may adhere to it. Respecting the accuracy of the charge, see [Table rocket], in the chapter on Table fire-works.
The garnishing, or furniture, should not exceed, in any case, one-third the weight of the rocket. The head is made of pasteboard, first moistened, and then rolled round a conical former. It must enter the mould, and, when inserted, ought to be pasted round the juncture with paper. (See [sec. iii, and iv.])
With respect to rocket sticks, as they are used for counter-weights, Morel remarks, that, for rockets up to an inch and a quarter, they may be formed of the branches of light wood, as hazle, elder, &c. and for rockets above that caliber, heavy wood, but perfectly straight and without knots, may be used. As a general rule, the sticks are made ten or twelve times the length of the rocket, and in thickness about one-third of the exterior diameter of the case. In the large end of the stick, there is a gutter or groove, formed to receive the rocket. When branches are used, they must also lie straight, and cut flat at the large end, about half their thickness, so that they may be joined to the rockets with a pack-thread, or fine iron wire. If the stick is too weighty, it may be shaved off the whole length. Rockets, we may remark, that are not well balanced by the stick, will not ascend regularly. If the stick be too light, they will rise in a zigzag direction; but, if too heavy, their accelerated force will be diminished, their motion slow, and, when they arrive at a certain height, they will fall in a semicircular position. (See section v, of this chapter, [on the Dimensions and Poise of rocket sticks.])
We may further remark, that all rockets are formed and proportioned by the diameter of their orifice. When the height is six and two-thirds diameter, the foot should be one diameter and two-thirds. The choak of the mould, if used, is one diameter and one-third in height, which must be made out of the same piece as the foot, and fit tight in the mould. There must be an iron pin to keep the foot fast. The nipple is half a diameter high, and two-thirds thick, and made of the same metal as the piercer. The height of the piercer is three and a half diameters, and at the bottom one-third of a diameter thick, and from thence tapering to one-sixth of a diameter. The best mode of fixing the piercer in the cylinder, is to make that part below the nipple sufficiently long to go entirely through the foot, and rivet at the bottom. The former or roller, for the cases, is seven and a half diameters from the handle, and its diameter is two-thirds of the bore. The end of the former is one diameter and two-thirds long, and of the thickness given above. The small part, which fits in the hole in the end of the roller, when the case is pinched, is one-sixth and one-fourth of the diameter of the mould thick. The first drift, or rammer, must be six diameters from the handle; and this, as well as all other rammers, must be a little thinner than the former, to prevent the sacking of the paper, when the charge is driven. In the end of this rammer must be a hole to fit over the piercer. Several hollow rammers are used in completing the charge. (See our remarks in part second on [Charging of cases.])
The diameter of the nipple should always be equal to that of the former. With regard to the thickness of moulds, it is immaterial, provided they are substantial and strong. Solid driving is more expeditious than charging over a piercer; but great labour and attention is required in boring them, an account of which, with the apparatus required, may be seen in Part second.
The following table of the dimensions of rocket-moulds, if the rockets are rammed solid, may be useful.
| Weight of rockets. | Length of their moulds without their feet. | Internal diameter of the moulds. | Height of the nipples. | |
| lbs. | oz. | Inches. | Inches. | Inches. |
| 6 | 0 | 34.7 | 3.5 | 1.5 |
| 4 | 0 | 38.6 | 2.9 | 1.4 |
| 2 | 0 | 13.35 | 2.1 | 1.0 |
| 1 | 0 | 12.25 | 1.7 | 0.85 |
| 0 | 8 | 10.125 | 1.333 &c. | 0.6 |
| 0 | 4 | 7.75 | 1.125 | 0.5 |
| 0 | 2 | 6.2 | 0.9 | 0.45 |
| 0 | 1 | 4.9 | 0.7 | 0.35 |
| 0 | 0½ | 3.9 | 0.55 | 0.25 |
| 6 | drachms. | 3.5 | 0.5 | 0.225 |
| 4 | drachms. | 2.1 | 0.3 | 0.2 |
Sec. III. Of the Heading of Rockets.
The heads for sky-rockets must always bear a given proportion to the rockets.