Laboratory

signifies that place where all sorts of fire-works are prepared, both for actual service, and for pleasure, viz. quick matches, fuses, portfires, grape-shot, case-shot, carca es, hand-grenades, cartridges, shells filled, and fuses fixed, wads, . . Aigrettes . See Mortars . Balls are of various sorts, shapes and forms; as Chain-shot , are two shot linked together by a strong chain of 8 or 10 inches long; they are more used on board men of war, than in the land service. The famous M. de Witt was the first inventor, about the year 1665. Light-balls , of which there are several sorts: the best composition is mealed powder 2, sulphur 1, rosin 1, turpentine 2¹⁄₂, and saltpetre 1¹⁄₂. Then take tow, and mix and dip it in this composition, till of a proper size, letting the last coat be of mealed powder. Or take thick strong paper, and make a shell the size of the mortar you intend to throw it out of, and fill it with a composition of an equal quantity of sulphur, pitch, rosin, and mealed powder; which being well mixed, and put in warm, will give a clear fire, and burn a considerable time. The composition for filling balls that are intended to set fire to magazines is, mealed powder 10, saltpetre 2, sulphur 4, and rosin 1; or mealed powder 4, pounded gla 1, antimony ¹⁄₂, camphor ¹⁄₂, sal-ammoniac 1, common salt ¹⁄₄; or mealed powder 48, saltpetre 32, sulphur 16, rosin 4, steel or iron filings 2, fir tree saw-dust boiled in saltpetre ley 2, and birch wood charcoal 1. With any of these compositions fill the sack, and ram it, if po ible, as hard as a stone, putting in the opening, a fuse, and about the same an iron ring ¹⁄₅th of the ball’s diameter wide; and on the opposite end, another ring ¹⁄₆th of the ball’s diameter; then with a strong cord of ¹⁄₄th of an inch diameter, lace round the hoops, or rings, from one end of the ball to the other, as often as is requisite; this is called the ribbed coat; then lace it again the contrary way, which is called the check coat. Between each square cord, iron barrels are driven in, ¹⁄₃d of which are filled with powder, and a bullet: at the end of each a small vent is made, that the composition may inflame the powder, and drive the balls out on every side, which not only kill numbers of people, but prevent any one from extinguishing the fire-ball. The whole must, when finished, be dipped in melted pitch, rosin and turpentine oil; which composition fastens the whole together. Smoke-Balls , are made and contrived to give an uncommon smoke, and thereby prevent the enemy from seeing what you are about. They are prepared as above, only the composition must be 5 to 1 of pitch, rosin, and saw-dust: the ingredients are put into iron shells, having 4 holes each to let out the smoke, and are thrown out of mortars. | Stink- | | - | Balls. See Balls. | | Poisoned- | | Red-hot- | | Chain- | | Stang- | | Anchor- | Me age-Balls. See Shells . Fire-Barrels are at present not much used: they were of different sorts; some mounted on two wheels. The inside of the barrel is loaded with powder, and the outside full of sharp iron points, intermixed with grenades loaded, and fuses fixed. Sometimes they are placed under ground, and made use of to annoy the enemy’s approach. Carca , in military affairs, was formerly of an oval form, made of iron bars, and filled with a composition of mealed powder, saltpetre, sulphur, broken gla , shavings of horn, pitch, turpentine, tallow, and linseed oil, covered with a pitched cloth; it is primed with mealed powder and quick match, and fired out of a mortar. Its design is to set houses on fire, . See Carca . None but round carca es are used at present, the flight of the oblong ones being so uncertain. The composition is, pitch 2, saltpetre 4, sulphur 1, and corned powder 3. When the pitch is melted, the pot is taken off, and the ingredients (well mixed) put in; then the carca is filled with as much as can be pre ed in. Cartridges are made of various substances, such as paper, parchment, bladders, and flannel. When they are made of paper the bottoms remain in the piece, and accumulate so much, that the priming cannot reach the powder; besides other inconveniencies. When they are made of parchment or bladders, the fire shrivels them up, so that they enter into the vent, and become so hard, that the priming iron cannot remove them so as to clear the vent. Nothing has been found hitherto to answer better than flannel, which is the only thing used at present for artillery cartridges of all sorts; because it does not keep fire, and is therefore not liable to accidents in the loading: but, as the dust of powder pa es through them, a parchment cover is sometimes made to put over them, which is taken off when used. The best way of making flannel cartridges, is to boil the flannel in size; which will prevent the dust of powder from pa ing through, and render it stiff, and more manageable; for without this precaution cartridges are so pliable, on account of their size and the quantity of powder they contain, that they are put into the piece with much difficulty. The loading and firing guns with cartridges is done much sooner than with loose powder, and fewer accidents are likely to occur. The heads of cartridges, especially for musquetry, are sometimes wrapped in coarse cotton. In quick firing the shot is fixed to the cartridge by means of a wooden bottom, hollowed on one side so as to receive nearly half the shot, which is fastened to it by two small slips of tin cro ing over the shot, and nailed to the bottom; and the cartridge is tied to the other end thereof. They are fixed likewise in the same manner to the bottoms of grape shot, which are used in field pieces. Grape-shot , in artillery, is a combination of small shot, put into a thick canvas bag, and corded strongly together, so as to form a kind of cylinder, whose diameter is equal to that of the ball which is adapted to the cannon. To make grape shot , a bag of coarse cloth is made just to hold the bottom which is put into it; as many shot are then thrown in as the grape is to contain; and with a strong pack thread the whole is quilted to keep the shot from moving. The bags, when finished, are put into boxes for the purpose of being conveniently carried. The number of shot in a grape varies according to the service or size of the guns: in sea service 9 is always the number; but by land it is increased to any number or size, from an ounce and a quarter in weight, to four pounds. It has not yet been determined, with any degree of accuracy, what number and size answer best in practice; for it is well known, that they often scatter so much that only a small number takes effect. Of the three different sorts of cannon which are used for throwing grape-shot, the 3-pounder seems rather the best; especially when two are used, as the effect of two 3-pounders is much greater than that of one 6-pounder. But the 8-inch howitzer, which can be made to throw in from three to five of its charge (from 12 to 20lb. of shot) becomes thereby a very formidable piece, when it can be used for grape-shot; and this is the howitzer used by the French light or horse artillery. Proper charges for grape-shot have never yet been effectually determined: we can only give our advice from some experiments; that for heavy 6-pounders, ¹⁄₃d of the weight of the shot appears to be the best charge of powder; for the light 6-pounders, ¹⁄₄th of the weight of the shot; and for howitzers, ¹⁄₈th or ¹⁄₁₀th answers very well. This kind of fire seems not yet to have been enough respected, nor depended on. However, if cannon and howitzers can be made to throw ¹⁄₃d or ¹⁄₄th, and sometimes half their charge of grape shot into a space 39 by 12 feet, at 200 and 300 yards distance, and those fired 7 or 8 times in a minute; it surely forms the thickest fire that can be produced from the same space. Tin case-shot , in artillery, is formed by putting a great quantity of small iron shot into a cylindrical tin box, called a canister, that just fits the bore of the gun. Leaden bullets are sometimes used in the same manner; and it must be observed, that whatever number or sizes of the shot are used, they must weigh, with their cases, nearly as much as the shot of the piece. Case shot , formerly, consisted of all kinds of old iron, stones, musquet balls, nails, . Tubes , in artillery are used in quick firing. They are made of tin: their diameter is ²⁄₁₀ths of an inch, being just sufficient to enter into the vent of the piece; about 6 inches long, with a cap above, and cut slanting below, in the form of a pen; the point is strengthened with some solder, that it may pierce the cartridge without bending. Through this tube is drawn a quick-match, the cap being fitted with mealed powder, moistened with spirits of wine. To prevent the mealed powder from falling out by carriage, a cap of paper or flannel, steeped in spirits of wine, is tied over it. Flambeaux , a kind of lighted torch, used in the artillery upon a march, or the park, . Formers , are cylinders of wood, of different sizes and dimensions, used in the laboratory , to drive the composition of fuzes and rockets. Funnels , are of various sorts, used to pour the powder into shells, and the composition into fuses, and rocket-cases. Fire-ship , a ve el filled with combustible materials, and fitted with grappling irons, to hook, and set fire to the enemy’s ships in battle, . From the bulk head at the fore castle to a bulk head to be raised behind the main chains, on each side and acro the ship at the bulk heads, is fixed, close to the ship’s sides, a double row of troughs, 2 feet distance from each other, with cro troughs quite round, at about 2¹⁄₂ distance; which are mortised into the others. The cro troughs lead to the sides of the ship, to the barrels and to the port holes, to give fire both to the barrels and to the chambers, to blow open the ports; and the side troughs serve to communicate the fire all along the ship and the cro troughs. The timbers of which the troughs are made, are about 5 inches square; the depth of the troughs, half their thickne ; and they are supported by cro pieces at every 2 or 3 yards, nailed to the timbers of the ship, and to the wood work which incloses the fore and main masts. The decks and troughs are all well paved with melted rosin. On each side of the ship 6 small port holes are cut, from 15 to 18 inches large, the ports opening downwards, and are close caulked up. Against each port is fixed an iron chamber, which, at the time of firing the ship, blows open the ports, and lets out the fire. At the main and fore chains, on each side, a wooden funnel is fixed over a fire barrel, and comes through a scuttle in the deck, up to the shrouds, to set them on fire. Both funnels and scuttles must be stopped with plugs, and have sail cloth or canvas nailed close over them, to prevent any accident happening that way, by fire, to the combustibles below. The port holes, funnels, and scuttles, not only serve to give the fire a free pa age to the outside and upper parts of the ship, and her rigging, but also for the inward air (otherwise confined) to expand itself, and push through those holes at the time of the combustibles being on fire, and prevent the blowing up of the decks, which otherwise must of course happen, from such a sudden and violent rarefaction of the air as will then be produced. In the bulk head behind, on each side, is cut a small hole, large enough to receive a trough of the same size of the others; from which, to each side of the ship, lies a leading trough, one end coming through a sally port cut through the ship’s side, and the other fixing into a communicating trough that lies along the bulk-head, from one side of the ship to the other; and being laid with quick match, at the time of firing either of the leading troughs, communicates the fire in an instant to the contrary side of the ship, and both sides burn together. Fire barrels , for a fire-ship, are cylindric, on account of that shape answering better both for filling them with reeds, and for stowing them between the troughs: their inside diameters are about 21 inches, and their length 33. The bottom parts are first filled with double-dipt reeds set on end, and the remainder with fire-barrel composition, which is, corned powder 30lb. Swedish pitch 12, saltpetre 6, and tallow 3, well mixed and melted, and then poured over them. There are 5 holes of 3-quarters of an inch diameter, and 3 inches deep, made with a drift of that size in the top of the composition while it is warm: one in the centre, and the other four at equal distances round the sides of the barrel. When the composition is cold and hard, the barrel is primed by well driving those holes full of fuze composition, to within an inch of the top; then fixing in each hole a strand of quick-match twice doubled, and in the centre hole two strands the whole length; all which must be well driven in with mealed powder: then lay the quick-match all within the barrel, and cover the top of it with a dipt curtain, fastened on with a hoop to slip over the head, and nailed on. Bavins , for a fire-ship, are made of birch, heath, or other sort of brushwood, that is both tough and quickly fired: in length 2.5, or 3 feet; the bush-ends all laid one way, and the other ends tied with two bands each. They are dipped, and sprinkled with sulphur, the same as reeds, with this difference, that the bush ends, only, are dipped, and should be a little closed together by hand, as soon as done, to keep them more compact, in order to give a stronger fire, and to preserve the branches from breaking in shifting and handling them. Their composition is, rosin 120lb., coarse sulphur 90, pitch 60, tallow 6, and mealed powder 12, with some fine sulphur for salting. Iron-chambers , for a fire-ship, are 10 inches long, and 3.5. in diameter; breeched against a piece of wood fixed acro the holes. When loaded, they are almost filled full of corned powder, with a wooden tompion well driven into their muzzles. They are primed with a small piece of quick-match thrust through their vents into the powder, with a part of it hanging out; and when the ship is fired, they blow open the ports, which either fall downwards, or are carried away, and so give vent to the fire out of the sides of the ship. Curtains , for a fire-ship, are made of barras, about 3-quarters of a yard wide, and 1 yard in length: when they are dipped, 2 men, with each a fork, must run the prongs through the corner of the curtain at the same end; then dip them into a large kettle of composition (which is the same as the composition for bavins) well melted; and when well dipped, and the curtain extended to its full breadth, whip it between 2 sticks of about 5.5 feet long, and 1-5 inches square, held close by 2 other men to take off the superfluous composition hanging to it; then immediately sprinkle saw-dust on both sides to prevent it from sticking, and the curtain is finished. Reeds , for a fire-ship, are made up in small bundles of about 12 inches in circumference, cut even at both ends, and tied with two bands each: the longest sort are 4 feet, and the shortest 2.5; which are all the lengths that are used. One part of them are single dipped, only at one end; the rest are double-dipped, i. e. at both ends. In dipping, they must be put about 7 or 8 inches deep into a copper kettle of melted composition (the same as that for bavins;) and when they have drained a little over it, to carry off the superfluous composition, sprinkle them over a tanned hide with pulverised sulphur, at some distance from the copper.