When fuses have been well loaded, and the materials previously well mixed, they will naturally burn with an equal steady fire, preserving in general an even length of flame, without splitting, or irregularly shaking. They may be proved by throwing them into water, tied to a stone, or by driving them with heavy blows into the earth. They should not go out in either of these cases. Fuses made with the composition we shall describe, and for 10 and 12 inch shells, last seventy seconds. According to the Strasbourg directions, it appears, that fuses for shells of 12.78 inches should last until you can count 80 or 85, or 70 seconds. Those for bombs 8.52 inches, 65 counts, or 60 seconds, and those for grenades 25 or 30 counts.
Before the fuse is driven into the bomb, the thin or small end must be cut off, in order that the fire may be easily communicated to the mass of gunpowder, which is lodged in the bomb. To fire bombs at a small distance, the fuse must be cut on a longer slant, so that the bomb may take effect sooner, and may not remain a long time in the place where it falls, without bursting.
The fuse must be of such a length, as to continue burning all the time the shell is in its range, and to set fire to the powder as soon as it touches the ground, which occasions the shell instantly to burst into many pieces. When the distance from the object is known, the time of the shell's flight may be computed to a second or two; which being ascertained, the fuse may be cut accordingly. By burning two or three, and making use of a watch, or of a string, by way of a pendulum, to vibrate seconds, we may determine the length of time a fuse, or any length of a fuse, will take to burn.
In order to preserve fuses for a length of time, and protect them from moisture, the cap is coated with a composition, or cement, made of 16 parts of bees' wax, and 4 of mutton tallow; melting the wax first, and then adding the suet. Some make use of two-thirds wax, and one-third rosin. The cap of the fuse is dipped in, when the mixture is half cold, and immediately withdrawn.
| Composition for the Fuses of Shells, Howitzes and Grenades. | PARTS OF | |||||
| Meal | Salt- | Sul- | Char- | |||
| powder. | petre. | phur. | coal. | |||
| Composition usually employed, | 5 | 3 | 2 | |||
| Quicker composition, | 7 | 4 | 2 | |||
| Another (from Ruggeri) | 14 | 6 | 8 | |||
| Do. | Do. | 16 | 7 | 10 | ||
| Do. | (English) | 7 | 3 | 4 | ||
| Do. | (Strasbourg) for 8.52 bombs, | 4 | 2 | 3 | ||
| Do. | (from the Pocket Gunner) lbs. | 2¾ | 1 | 3¼ | ||
| Do. | particular (from Bigot) | } | 2⅝ | 6¾ | ⅝ | |
| } | 3⅞ | 9¼ | ⅞ | |||
The following is the quantity of composition required for fuses, viz:
| 1000 | fuses, | for 10 and 12 inch shells, | 92 | lbs. |
| Do. | do. | for 8 inch shells, | 53 | — |
| Do. | do. | for 6 inch howitzes, | 33½ | — |
| Do. | do. | for hand grenades | 16 | — |
Sec. II. Of Loading Shells, Howitzes and Grenades.
The shells, before they are loaded, are cleansed from any foreign substances that may be in them; and those which are split, or have flaws in the eye are rejected; so are also those that are not well bored, or are eccentric. They are then charged with powder, introduced into them by means of a funnel. Five or six pounds of gunpowder are usually put into twelve-inch shells; from three to five, in ten-inch shells; from one to one and a quarter, into eight-inch shells; from three-quarters to one pound, into howitzes; and grenades of all sorts are half filled. The charge of shells is increased, when they are to burst into a great number of pieces; for instance, when they are to fall among troops. Incendiary fire-works are added, when buildings are to be set on fire. Among these are fire-stone, and incendiary matches.