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A Military Dictionary, explaining and describing the Technical Tertis, Pbrafes, Works, and Machines,, used in the Science of, War.
25. 60. fewed. Robinson. THE present hostile appearance in many parts of the king
dom, and the impending war between Great Britain and France, seem to have given rise to this publication; and as our newspapers are daily entertaining their readers with re. views, rencounters, maneuvres, battles, sieges, &c. &c. at the several encampments, this performance appears to be intended as a vade-mecum for the military quidnuncs, to whom an explanation of terms and phrases peculiar to the art of war, will be an useful and acceptable present.-We are the rather inclined to consider the publication in this light, as we meet with little more than definitions or descriptions of the technical terms, machines, and works, frequently made use of. These are in general tolerably exact, and not ill drawn up, though sometimes they have much the appearance of translations from some French work ; which nevertheless may be owing to the frequent descriptions taken from the numerous French writings on this subject, where only such accounts are to be met with.
The compiler of this Dictionary, however, does not seem to be sufficiently acquainted with the subject, or at least not to have consulted the alterations and improvements in the military art, of modern times. This appears from his frequent use of obsolete terms, and sometimes giving accounts of things as laid down by old writers rather than from modern and improved relations. Thus under the term Bullet, he says,
• According to Marsenne, a bullet shot out of a great gun, fies ninety-two fathoms in a second of time, being equal to five hundred and eighty-nine English feet and a half; but according to some very accurate experiments of Mr. Derham, 'it only fies at its first discharge five hundred and ten yards in five half seconds.'
That is, about 500 or 600 feet in a second of time ; whereas it is now well known that such balls are usually projected with a velocity from 1000 to 1500, or even zooo feet per
second, Again, under the word Cannon, he remarks,
• The metal of which cannons are composed, is either iron, ur, which is more common, a mixture of copper, tin and brass ; the tin being added to the copper to make the metal more dense and compact; so that the better and heavier the copper is, the less tin is required. Some to an hundred pounds of copper add. ten of tin, five of brass, and ten of lead.
VOL, XLVI. Sept. 1778,
• Braudius describes a method of making cannon of leather, and it is certain the Swedes made use of such in the long war in the last century; but they were too apt to burst to be of much service. Iron cannon are not capable of so much regstance as those of brass, but as they are less expensive they are often used aboard ships, and in several fortified places.
• The parts and proportions of cannon about eleven feet long are, the barrel or cavity nine feet ; its fulcrum or support foorteen ;
and its axis seven ; the diameter of the bore at the mouch fix inches two lines; the plug of the ball two lines; the diameter of the ball therefore fix inches, and its weight thirty-three pounds and one-third ; the thickness of the metal about the mouth two inches, and at the breech fix; the charge of powder from eighteen to twenty pounds. It will carry a point black fix hundred paces, and may be loaded ten times in an hour, and often more. Cannon often fired must be carefully cooled, or else they will burft,
• Cannons are diftinguished by the diameters of the balls they carry. The rule for their length, &c. is that it be such that the whole charge of powder be on fire before the ball quit the piece. If it be made too long, the quantity of air to be driven out before the ball, will give too much resistance to the impulse; and that impulse ceasing, the friction of the ball again it the surface of the piece will leffen its velocity.
Formerly cannon were made much longer than they are at present; but some being by chance made two feet and a half shorter than ordinary, it was found that they threw a ball with greater force through a less space than the larger. This was confirmed by experience in 1624, by Gustavus Adolphus of Sweden ; ao iron ball of forty-eight pounds weight being found to go further from a fhort cannoni, than another ball of ninety. fix pounds out of a longer piece; whereas in other respects it is cercain the larger the bore and ball the greater the range,
• The greatest range of a cannon is ordinarily fixed at fortyfive degrees, but Dr. Halley thews it to be at forty-four and a half. M. S. Julien adjusts the ranges of the several pieces of cannon, from the weight of the ball they bear, the charge of powder being always supposed to be in a subduplicate ratio to the weight of the ball'.
In this article are many mistakes ; for guns are now usu. ally made of iron, because found to be much stronger and more durable, as well as cheaper than the composition with brass; for guns of this latter metal soon become unserviceable by running and melting into a large hole at the vent; by being foon spoiled in the chase by the friction of the balls; and 'becoming bent, with hot service, like a stick of sealing-wax when warm ; so that now only one ship in the navy has brass guns. Neither is the greatest range at an elevation of 45 degrees, nor even near it, unless the initial velocity be very small; every
different velocity and ball requiring a different elevation to produce the greatest range; from 45 degrees downwards gradually to 30, or even less in very great velocities.
Under the same article of Cannon, he observes, the new cannon, that are inade after the Spanish manner, have a cavity or chamber at the bottom of the barrel, which helps their effe&t.' But this is not the case at present, the cannon being now made with a plain cylindrical bore, without any chamber at the top. The article Gunpowder is well drawn up, and is as follows :
Gunpowder, a composition made of faltpetre, sulphur, and charcoal, incorporated and granulated, which readily takes fire and expands with incredible force.
• Bartholdus Schwartz, or the Black, was the first who taught the use of gunpowder to the Venetians in 1380; but what shews gunpowder to be of an older æra is, that the Moors, being befieged in 1343, by Alphonsus, discharged a sort of iron mortars that made a noise like thunder. There is mention made of
gunpowder in the registers of the chambers of accounts in France, as early as 1338. In short, our countrymen Roger Bacon knew of gunpowder one hundred and fifty years before Schwartz was born : for that friar exprefly mentions the composition in his treatise De Nullitate Magiæ.
• In order to reduce the nitre to powder, they dissolve a large quantity of it in as small a proportion of water as poslible; the keeping it continually ftirring over the fire, till the water exhales, a white dry powder is left behind.
• In order to purify the brimstone employed, they diffolve it with a very gentle heat; then scum and pass it through a double ftrainer. If the brimstone should happen to take fire in the melting, they have an iron cover that fits on close to the melting veffel, and damps the flame. The brimstone is judged to be sufficiently refined if it melts without yielding any fotid odour, between two hot iron plates, into a kind of red subAtance.
• The coal for making of gunpowder is either of the willow or hazel, well charred 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 fal ammoniac; and to continue thus stamping them together for twenty-four hours; after which the mass is fit for coining, and drying in the sun, or otherwise, so as sedulously to prevent its firing.
• The explofve force of gunpowder is now a thing commonly koown ; but the phyfical reason thereof may not, perhaps, be hitherto fufficiently understood. In order to explain it, let us 02
observe, 1. That falt.petre, of itself, is not inflammable ; and though it melts in the fire, and grows red hot, yet does not ex. plode, onless it comes in immediate contact with the coals. 2. That brimstone easily melts at the fire, and easily catches flame. 3. That powdered charcoal readily takes fire, even from the sparks yielded by a fint and steel. 4. That if nitre be mixed with powered charcoal, and brought in contact with the fire, it burns and flames. 5. That if sulphur be mixed with powdered charcoal, and applied to the fire, part of the fulphur burns flowly away, but not much of the charcoal. And, 6. That if a lighted coal be applied to a mixture of nitre and sulphur, the the fulphur presently takes fire, with some degree of explofion, leaving a part of the nitre behind ; as we fee in making the sal prunella and fal polycreflum.
• These experiments, duly considered, may give us the chemical cause of the ftrange explosive force of gunpowder : for each grain of this powder, consisting of a certain proportion of sulphur, nitre, and coal, the coal presently takes fre, upore contact of the same spark; at which time both the fulphur and the nitre immediately melt, and, by means of the coal interposed between them, burst into flame, which spreading from grain to grain propagates the same effect almost instantaneously; whence the whole mass of powder comes to be fired : and as nitre contains a large proportion both of air and water, which are now violently rarified by the heat, a kind of fiery explosive blaft is thus produced; wherein the nitre seems, by its aqueous and ærial parts, to act as bellows to the other inflammable bodies, sulphur and coal, blow them into a flame, and carry off their whole substance in smoke and vapour.
• The discovery of this composition was accidental, and per. haps owing to the common operation of fulminating nitre with sulphur, for making of fal-prunella : it appears to have been known long before the time of Schwartz, as beirg particularly mentioned by friar Bacon, as we have before obferved..
• The three ingredients of gunpowder are mixed in various proportions, according as the powder is intended for musquets, great guns, or mortars ; though those proportions leem hitherto not perfectly adjusted, or settled by competent experience.
• There are two general methods of examining gunpowder : one with regard to its purity, the other with regard to its ftrength: its purity is known by laying two or three little heaps near each other upon white paper, and firing one of them ; for if this takes fires readily, and the smoke rifes upright, without leaving any dross, cr feculent matter behind, and without burning the paper, or firing the other heaps, it is esteemed a sign that the fulphur and nitre were well purified ; and the coal was good; and all the three ingredients were thoroughly incorporated together : but, if the other heaps also take fire at the same time, si is presumed, that ei her common salt was mixed with the piire, or that the coal was not well ground, or the whole mass
'not well beat and mixed together; and, if the nitre or fula phur was not well purified, the paper will be black or spotted,
In order to try the ftrength of gunpowder, there are two kinds of inftruments in use; but neither of them appear more exact than the common method of trying to what distance a certain weight of powder will throw a ball from a musquet.
• To increase the strength of powder, it seems proper to make the grains considerably large, and to have it well fifted from the smallest dust. We see that gunpowder reduced to duft has but little explosive force ; but, when the grains are large, the flame of one grain has a ready passage to another, so that the whole parcel may thus take fire near the same time ; otherwise much force may be lost, or many of the grains go away, as shot unfired.
- It should also seem that there are other ways of increasing
enemy is accustomed to them, it is very difficult for troops to preserve their order. When a retreat is necessary, their diorfes have so much fire, and are fo indefatigable, their equipage fo'light, and themselves such excellent horsemen, that no other cavalry can pretend to follow them; they leap over ditches, and swim over rivers with great facility. They are retained in the service of most princes on the continent. They are resolate partisans, and are far better in an invasion or hasty expedition, than in a fet battle.'
An Introduâion is prefixed to the work, containing some pertinent obfervations on fortification ; accompanied with two copper-plates, containing a general plan of fortification, and the manner of carrying on a fiege ; and a representation of the several military utenfils described in the Dictionary.--At the end is subjoined a translation of · The New Method of Fortification, by the late Marshal Saxe, explained ; with some Observations on the present Method of fortifying Towns, and the Reasons why they are so liable to be reduced.'
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