Sec. IV. Of the Dimensions of Fuses, and the Dimensions and Charge of Bombs, Howitzes and Grenades.
Shells, in gunnery, are hollow iron balls, to be thrown out of mortars or howitzers, with a fuse hole of about an inch in diameter, to load them with powder, and to receive the fuse. The bottom, or part opposite the fuse, is made heavier than the rest, that the fuse may fall uppermost. In small elevations, this is not always the case, nor is it necessary.
Shells are called hollow projectiles, and, besides powder, various incendiary matters are introduced; but in addition to shells, properly so called, hollow projectiles comprehend howitzes and grenades. As a principle, it is observed, that their sides ought to be proportionably thick to the shock they receive in the piece, and to the quantity of powder introduced for bursting them; and their weight, according to the objects they are to destroy. We remarked, that a shell should be thicker opposite the fuse. This thickness is called by the French a culot, or reinforcement of metal; the object of which is to prevent the breaking of the shell on rocks or stone, as well as to prevent its falling on the fuse. Four times as much powder may be put in the cavity as is sufficient to burst them. This admits the introduction of incendiary matter. Howitzes are hollow balls with a culot, or reinforcement of metal, upon the inside, opposite the eye, and are calculated for ricochet, that is, for passing, bounding, over the ground, and, by striking and penetrating solid objects, and finally bursting, produce considerable havoc and devastation. For ricochet, the howitz, in fact, should be of the same thickness throughout.
Grenades are also a hollow ball, and are of two kinds; namely, the rampart or ditch grenades, of the caliber of 36, 24, 18, and 12 pounders, designed for rolling along a trough from the top of the rampart, and falling into the ditch, to annoy an enemy, in attempting to cross it; and the hand-grenade, that are thrown by hand into the interior of works, that are attacked, into covered ways and trenches, &c. They are of six and three pounder calibers, and their splinters will fly 35 yards. Grenades were invented about the time that shells were, and first used in 1594. Grenades have sunk into disuse; but they may be advantageously employed. During the seige of Cassel, under the count de la Lippe, in the campaign of 1762, a young engineer undertook to carry one of the outworks, with a small detachment of men by using grenades, and in consequence succeeded.
Message shells are nothing more than howitzer shells, and are so called, because they are used to carry letters or papers. During the bombardment of Flushing, and while the communication with Cadsand was cut off, means were found to convey a letter from the garrison into the latter place. It was inclosed in a shell without inflammable matter, and discharged from a mortar, planted on one of the sea batteries.
Shrapnel shells were invented by colonel Shrapnel of the British service. They were used, we are told, with peculiar effect against the French, in 1808, and at the battle of Waterloo in 1815. The fuses for these shells, after being turned so as to fit the fuse-holes, are bored, and a deep thread grooved inside, to hold the composition firm; and, instead of being turned with cups, they are hollowed conical, and roughed with a tool that cuts under, the better to receive the priming. After they are driven, with fuse composition, one and a half inches, they are sawed across the top about one-fifth of an inch down, so as not to touch the composition, and divided into five equal parts, of two-tenths of an inch each; after which, a bit of quickmatch is placed across, and drawn tight in the same grooves. They are then primed with meal-powder and spirits of wine, capped, and packed for service.
We here insert three tables, which we have extracted from the work of M. Bigot.
The first table is relative to the dimensions of fuses for shells, howitzes, and grenades; the second, respecting the dimensions of bombs, howitzes, and grenades; and the third, of the charge of bombs and howitzes.
These tables, taken together, will exhibit all the particulars on this subject; and as this kind of data is necessary, in the practical operations of the laboratory, their introduction in this place, we consider important.
Table relative to the Dimensions of Fuses for Shells, Howitzes, and Grenades.