Sec. IX. Of Balloon Cases, or Paper Shells.
First, prepare an oval former, turned out of smooth wood; then paste a quantity of brown, or cartridge paper, and let it lie until the paste is quite soaked through. This being done, rub the former with soap or grease, to prevent the paper from sticking to it. Next, lay the paper on in small slips, until you have made it one-third the thickness of the shell intended. Having this done, set it to dry; and when dry, cut it round the middle, and the two halves will easily come off: but, observe, when you cut, to leave about one inch not cut, which will make the halves join much better than if quite separated. When you have some ready to join, place the halves even together, and paste a slip of paper round the opening, to hold them together, and let them dry. Then lay on paper, all over as before, every where equally, excepting that end which goes downward in the mortar, which may be a little thicker than the rest; for that part, which receives the blow from the pounder in the chamber of the mortar, consequently requires the greatest strength.
When the shell is perfectly dry, burn a vent at the top, with an iron, large enough for the fuse. This method will answer for balloons from 4 inches 2/5ths, to 8 inches in diameter; but, if they are larger, or required to be thrown to a great height, let the first shell be turned of elm, instead of being made of paper.
For balloons 4 inches 2/5ths, let the former be 3 inches 1/8th, in diameter, and 51/2 inches long. For a balloon of 51/2 inches, the diameter of the former must be 4 inches, and 8 inches long. For a balloon of 8 inches, let the diameter of the form be 5 inches and 15/16ths, and 11 inches 7/8ths long. For a 10 inch balloon, let the form be 7 inches 3/16ths, in diameter, and 141/2 inches long. The thickness of a shell for a balloon of 4 inches 2/5ths, must be 1/2 an inch. For a balloon of 51/2 inches, let the thickness of the paper be 5/8ths, of an inch; for an 8 inch balloon, 7/8ths, of an inch; and for a ten inch balloon, 1 inch and 1/8th of an inch.
Shells, that are designed for stars only, may be made quite round, and the thinner they are at the opening, the better; for if they are too strong, the stars are apt to break at the busting of the shell. When making the shell, employ a pair of callipers, or a round gage; so that you may not lay the paper thicker in one place than other, and also that you may be able to know, when the shell is of a proper thickness. Balloons must always be made to go easy into the mortars. (See Encycl. Brit. Art. Balloon cases.)
Sect. X. Of Cases for Illumination Port-fires.
These must be made very thin, of paper, and rolled on formers; from 2 to 3/8ths of an inch in diameter, and from 2 to 6 inches long: they are pinched close at one end, and left open at the other. When they are to be filled, put in but a little composition at a time, and ram it lightly, so as not to break the case. Three or four rounds of paper, with the last round pasted, will be sufficiently strong for these cases. (Ibid.)
Sect. XI. Of Cases and Moulds for Common Port-fires.
Common port-fires, are intended purposely to fire the works, their fire being very slow, and the heat of the flame so intense, that, if applied to rockets, leaders, &c. it will fire them immediately. When used, they are held in copper sockets, fixed in the end of a long stick. These sockets are made like port-crayons, only with a screw instead of a ring.
Port-fires, or lances of service of the French, may be made of any length, but are seldom more than 21 inches long.