Cafsacable Deck. A Cannon Mounted on it's Carriage. it's Carriage. Cartouches. Junie. Brent. Shot in the form Cartridge. Angels. Chain Shot. WArchibald sculpt. Practice. and expose it to the sun, or put it in a frying-pan; and when it is well dried, 5 lb. or 6 lb. of this powder is put into the petard, which reaches within three fingers of the mouth: the vacancies are filled with tow, and stopped with a wooden tompion; the mouth being strongly bound up with cloth tied very tight with ropes; then it is fixed in the madrier, that has a cavity cut in it to receive the mouth of the petard, and fastened down with ropes. Some, instead of gunpowder for the charge, use one of the following compositions, viz. gunpowder seven pounds, mercury sublimate one ounce, camphor eight ounces; or gunpowder six pounds, mercury sublimate three ounces, and sulphur three; or gunpowder six, beaten glass half an ounce, and camphor three quarts. Before any of these pieces are appropriated for service, it is necessary to have each undergo a particular trial of its soundness, which is called a proof, to be made by or before one authorized for the purpose, called the proof-master. To make a proof of the piece, a proper place is chosen, which is to be terminated by a mount of earth very thick to receive the bullets fired against it, that none of them may run through it. The piece is laid on the ground, supported only in the middle by a block of wood. It is fired three times; the first with powder of the weight of the bullet, and the two others with of the weight; after which a little more powder is put in to singe the piece; and after this, water, which is impressed with a spunge, putting the finger on the touch-hole to discover if there be any cracks; which done, they are examined with the cat, which is a piece Practice. of iron with three grasps, disposed in the form of a triangle, and of the caliber of the piece; then it is visited with a wax-candle, but it is of very little service in the small pieces, because if they be a little long, the smoke extinguishes it immediately. See Plate CCXLIX. Besides the large pieces already mentioned, invented Of small for the destruction of mankind, there are others called arms. small guns; viz. muskets of ramparts, common muskets, fusils, carabines, musketoons, and pistols. A musket, or musquet, is a fire-arm borne on the shoulder, and used in war, formerly fired by the appli cation of a lighted match, but at present with a flint and lock. The common musket is of the caliber of 20 leaden balls to the pound, and receives balls from 22 to 24 its length is fixed to 3 feet 8 inches from the muzzle to the touch-pan. A fusil, or fire-lock, has the same length and caliber, and serves at present instead of a musket. A carabine is a small sort of fire-arm, shorter than a fusil, and carrying a ball of 24 in the pound, borne by the light-horse, hanging at a belt over the left shoulder. This piece is a kind of medium between the pistol and the musket; and bears a near affinity to the arquebuss, only that its bore is smaller. It was formerly made with a match lock, but afterwards with a flint-lock. The musquetoon is of the same length of the carabine, the barrel polished, and clean within. It carries five ounces of iron, or seven and a half of lead, with an er al quantity of powder. The barrel of a pistol is generally 14 inches long. 57 Gunpow der. GUNPOWDER, a composition of nitre, sulphur, and charcoal, mixed together, and usually granulated; which easily takes fire, and, when fired, rarefies or expands with great vehemence, by means of its elastic force. It is to this powder we owe all the action and effect of guns, ordnance, &c. so that the modern military art, fortification, &c. in a great measure depend there on. Invention of Gunpowder. See GUN. Method of making GUNPOWDER. Dr Shaw's receipt for this purpose is as follows: Take four ounces of refined nitre, an ounce of sulphur, and six drams of small-coal: reduce these to a fine powder, and continue beating them for some time in a stone mortar with a wooden pestle, wetting the mixture between whiles with water, so as to form the whole into an uniform paste, which is reduced to grains, by passing it through a wire-sieve fit for the purpose; and in this form being carefully dried, it becomes the common gunpowder. For greater quantities mills are usually provided, by means of which more work may be performed in one day than a man can do in a hundred. The nitre or saltpetre is refined thus: Dissolve four or three days in a covered vessel of earth, with sticks Gunpow In order to reduce this salt to powder, they dissolve In order to purify the sulphur employed, they dissolve it with a very gentle heat; then scum and pass it through a double strainer. If the sulphur should happen to take fire in the melting, they have an iron cover that fits on close to the melting vessel, and damps the flame. The sulphur is judged to be sufficiently refined if it melts, without yielding any fetid odour, between two hot iron plates, into a kind of red sub stance. The coal for making gunpowder is either that of willow or hazel, well charged in the usual manner, and reduced to powder. And thus the ingredients are prepared for making this commodity but as these ingredients require to be intimately mixed, and as there would be danger of their firing if beat in a dry form, the method is to keep them continually moist, either with water, urine, or a solution of sal ammoniac: they continue thus stamping them together for 24 hours; after which the mass is fit for corning and der. a a Gunpow. drying in the sun, or otherwise, so as sedulously to pre- To increase the strength of powder, Dr Shaw thinks Gunpow. der. vent its firing. it proper to make the grains considerably large, and to wise much force may be lost, or many of the grains go He then loaded the pistol with a bullet, fired it against * Phil. On this subject Count Rumford * observes, that almost 举 an oaken plank about six feet from the muzzle, and Trans. all those who have written upon gunpowder, particu- observed the recoil and penetration of the bullet. He vol. lxxi. larly those of the last century, have given different re- next tried the effect of one of these small bladders of ceipts for its composition; and he proposes it as a water when put among the gunpowder, but always through the powder. To accomplish this dispersion powder could be augmented by this means. Twenty der.. der. its strength. Its purity is known by laying two or Gunpowthree little heaps near each other upon white paper, and firing one of them. For if this takes fire readily, and the smoke rises upright, without leaving any dross or feculent matter behind, and without burning the paper, or firing the other heaps, it is esteemed a sign that the sulphur and nitre were well purified, that the coal was good, and that the three ingredients were thoroughly incorporated together: but if the other heaps also take fire at the same time, it is presumed, that either common salt was mixed with the nitre, or that the coal was not well ground, or the whole mass not well beat and mixed together; and if either the nitre or sulphur be not well purified, the paper will be black or spotted. Gunpow. grains of brass dust were therefore mixed with 145 grains of powder; but still the force of the explosion was not augmented. In our author's opinion, however, neither brass dust nor ethiop's mineral diminish the force of the explosion otherwise than by filling up the interstices between the grains, obstructing the passage of the flame, and thus impeding the progress of the inflammation. Thus it appears, that little hope remains of augmenting the force of gunpowder by any addition either of liquid or inflammable solids: the reason is obvious; viz. because all of them, the liquids especially, absorb great quantities of heat before they can be converted into vapour; and this vapour, after it is formed, requires more heat to make it expand more forcibly than air: hence, as the effects of gunpowder depend entirely upon the emission of a quantity of air, and its rarefaction by vehement heat, the power must be greatly diminished by the absorption of this heat, which ought to be spent in rarefying air. Even solid bodies cannot be set on fire without a previous absorption of heat to convert them into vapour; but liquids have this property still more than solids, and must therefore diminish the explosive force still more. Lime added to gunpowder, however, is said to augment the power of the explosion by one third. In his experiments on gunpowder, Count Rumford had the curiosity to compare the strength of aurum fulminans, when enclosed in a gun-barrel, with that of common gunpowder; but his experiment only verified. what has been found by others, viz. that this powder which in the open air makes such a very violent report, bas in close vessels scarce any power, comparatively speaking, either of explosion or projecting a bullet. Count Rumford, however, taking it for granted that the power of aurum fulminans would be found much greater than that of gunpowder, took care to have a barrel of uncommon strength prepared for the experiment. The weight of it was 7 lb. 5 oz. ; the length 13.25 inches, and the width of the bore 0.55 inches. This barrel, being charged with 27.44 grains of aurum fulminans and two leaden bullets, which, together with the leather put about them to make them fit the bore without windage, weighed 427 grains; it was laid upon a chafingdish of live coals at the distance of about ten feet from the pen dulum, and the piece was directed against the centre of the pendulum. Some minutes elapsed before the powder exploded; but when it did so, the explosion did not much exceed the report of a well-charged airgun; and it was not until he saw the pendulum in motion, that Count Rumford could be persuaded that the bullets had been discharged. On examination, however, it was found that nothing had been left in the barrel, and that the powder had probably been all exploded, as a great many particles of the revived metal were thrown about. From a calculation of the motion communicated to the pendulum, it was found that the velocity of the bullets had been about 428 feet in a second; whence it appears that the power of aurum fulminans, compared with that of gunpowder, is only as 4 to 13 very nearly. Method of Trying and Examining GUNPOWDER.There are two general methods of examining gunpowder; one with regard to its purity, the other with regard to Several instruments have been invented to try thestrength of gunpowder; but they have generally been complained of as inaccurate. Mr Thomson, (now Count Rumford), in the 71st volume of the Philosophical Transactions, gives an account of an exact method of proving the strength of it. "As the force of powder (says he) arises from the action of an elastic fluid that. is generated from it in its inflammation, the quicker the charge takes fire, the more of this fluid will be generated in any given short space of time, and the greater of course will its effect be upon the bullet. But in the common method of proving gunpowder, the weight by which the powder is confined is so great in proportion to the quantity of the charge, that there is time quite sufficient for the charge to be all inflamed, even when the powder is of the slowest composition, before the body to be put in motion can be sensibly removed from its place. The experiment therefore may show which of the two kinds of powder is the strongest, when equal quantities of both are confined in equal spaces, and both completely inflamed; but the degree of the inflammability, which is a property essential to the goodness of the powder, cannot by these means be ascertained. Hence it appears how powder may answer to the proof, such as is commonly required, and may nevertheless turn out very indifferent when it comes to be used in service. But though the common powder-triers may show powder to be better than it really is, they can never make it appear to be worse than it is: it will therefore always be the interest of those who manufacture the commodity to adhere to the old method of proof, but the purchaser will find his account in having it examined in a method by which its goodness may be ascertained with greater. precision. From several experiments it appears, that the effect of the charge is considerably augmented or diminished, according to the greater or less force employed in ramming it down. To prevent this inconvenience, Count Rumford advises the use of a cylindric ramrod of wood, fitted with a metal ring about an inch or an inch and a half in diameter; which being placed at a proper distance from the end which goes up into the bore, will prevent the powder from being too much compressed. In making experiments of this kind, however, it is necessary to pay attention to the heat of the barrel as well as to the temperature of the atmosphere; for heat and cold, dryness and moisture, have a very sensible effect upon gunpowder to augment or diminishe its force. When a very great degree of accuracy therefore |