[CHAPTER IV.]
OF FUSES FOR SHELLS, HOWITZES, AND GRENADES.
The fusée of the French, is applied to various purposes, and is differently made by different artificers. Fuses are intended to communicate fire to the powder with which shells, &c. are filled, so as to make them burst in the places to which they are thrown. They are composed, according to some, of one pound of gunpowder, and two or three ounces of charcoal, well mixed together; or of four pounds of gunpowder, two of saltpetre, and one of sulphur. It is to be remarked that the time a bomb, or grenade, will take to burn, after it has been thrown out of the mortar, or a howitz out of a howitzer, depends entirely upon the length and quality of the fuse. Fuses are made of wood turned in the form of a truncated cone, in order to enter fairly into the eye of the shell. They are perforated through the middle, in the direction of the axis, so as to receive the composition. This channel is called the light of the fuse. The wood that is employed, should be strong, dry, sound, and without knots. The best kinds are the oak, the elm, and the linden. They are filled with a slow combustible composition. The materials are increased or diminished according to the nature of their application. Fuses are sometimes made of copper.
The fuses for 10 and 12 inch shells are 81/2 inches long; for 8 inch shells, 71/2, for howitzes, 51/2; and for hand grenades, 21/2. The diameter of the light, in the first is 5 lines, in the second and third, 4 lines, and 2 lines for grenades. At the larger end of the fuse for shells, and howitzes, a cup is made from 10 to 14 lines in diameter, and 3 deep. In turning them, a solid bit, 21/2 inches thick, is left at the small end, to prevent them from splitting, when the composition is pressed into the canal. When the fuse is to be driven into the eye of the projectile, this piece is sawn off, cutting the fuse diagonally. The turner marks its termination by a circle upon the fuse. Fuses decrease nearly one inch in length, and two lines in diameter, according to the caliber of the bomb. The diameter of the lights, or apertures, only diminish half a line.
In what is called the Shrapnel shell, invented by colonel Shrapnel, the seasonable use of the fuse constitutes one of its principal advantages. With regard to the American elongated shell, invented by a gentleman in the Ordnance, we have heard nothing. See [Shrapnel shell], &c.
Sec. I. Of the Method of Charging the Fuses of Bombs or Shells.
Two rammers of copper are required for each of the several calibers of 12, 10, and 8 inches; the first an inch longer than the fuse, the second half as long. These rammers are of the same size with the lights of their respective fuses, and have a head to receive the blows of a mallet. Only one rod is wanted for the fuses of smaller calibers.
The first operation is to examine the fuses, to see that they have no knots or flaws, and are not wormeaten. The artificers place themselves astride, and facing each other, upon benches of strong plank, having, between them, a small vessel filled with the composition, and each one, a small measure. Each artificer takes a fuse, inserts the small end into a hole, made in the bench, for the purpose of maintaining it erect, and preventing it from splitting in the act of charging. He then passes a measure of the composition into the light, and introduces the first rod, on which he strikes 15 strokes, of equal force, with the mallet. Between every three strokes, he raises the rod, to make the composition fall. The ramming of this measure is therefore executed in 5 vollies or blows. He then withdraws the rod, and introduces a new charge of the composition, which he beats as before, and so on until the fuse is half full; after which he makes use of the second rod, and goes on loading, until the charge reaches within three lines of the cup. He then takes two strands of quick match, which (after placing them in the form of a cross, on the top of the fuse) he presses with his rod, pours some of the composition upon them, and, beating it carefully so as not to cut the match, he fills the fuse to the top of the cup.
The fuses of howitzes and grenades are charged in the same way; but the blows are not so heavy as in larger ones, for fear of splitting the wood.
The fuses being thus charged, the quick match is folded into the cup, and the opening closed with a bit of cloth or parchment, or very strong paper, which is tied an inch below the top. This operation is called capping the fuse. All the fuses for bombs or grenades are at present furnished with matches. Care must be taken, therefore, to leave a vacancy of about .27 parts of an inch, in order to fix in the match. Fuses of grenades are charged with the same precision as those for bombs, only the blows, as we remarked, should be weaker for fear of splitting the fuse. Before the little end is driven into the bomb or shell, care is to be taken to have the end cut slopingly, without which the communication of the fire with the powder would be uncertain.