As the performance of rockets depends much on their moulds, it is requisite to give a definition of them and their proportions, which are as follows: They are made and proportioned by the diameter of their orifice, which is divided into six equal parts: as for example, Fig. 6. represents a mould made by its diameter A B, its height from C to D is six diameters and two thirds; from D to E is the height of the foot, which is one diameter and two thirds; F the choak, or cylinder, whose height is one diameter and one third; it must be made out of the same piece as the foot, and fit tight in the mould; G an iron pin that goes through the mould and cylinder, to keep the foot fast; H the nipple, which is half a diameter high, and two thirds thick, and of the same piece of metal as the piercer I, whose height is three diameters and a half, and at the bottom is one third of the diameter thick, and from thence tapering to one sixth of the diameter: the best way to fix the piercer in the cylinder, is to make that part below the nipple long enough to go quite through the foot, and rivet it at the bottom. Fig. 7. is a former or rowler for the cases, whose length, from the handle, is seven diameters and a half, and its diameter two thirds of the bore A B; 8. the end of the former, which is of the same thickness and one diameter and two thirds long, the small part; which fits into the hole In the end of the rowler when the case is pinching, is one sixth and a half of the mould’s diameter thick. Fig. 9, the first drift, which 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 you are driving in the charge: in the end of this rammer is a hole to fit over the piercer; the line K marked on this is two diameters and one third from the handle, so that when you are filling the rocket, this line appears at top of the case; you must then take the second rammer, 10, which from the handle is four diameters; and the hole for the piercer is one diameter and a half long. Fig. 11. is the short and solid drift which you use when you have filled the case as high as the top of the piercer. It is to be observed, that all rammers must have a collar of brass at the bottom, to keep the wood from spreading or splitting; and that the same proportion be given to all moulds, from one ounce to six pound. I mentioned nothing concerning the handles of the rammers; however, if their diameter be equal to the bore of the mould, and two diameters long, it will be a very good proportion; but the shorter you can use them the better, for the longer the drift, the less will be the pressure on the composition, by the blow given with the mallet. A Table of Dimensions for Rocket Moulds, in which the Rockets are rammed solid.