a large province of Hindustan, in the Deccan, extending from the 19th to the 25th degree of N. latitude. The tract may be considered as comprising part of the British territory of Sangor and Nerhudda with the districts of Singrowlee, Chota Nagpore, and Sirgooja, the petty native states on the S.W. frontier of Bengal, the Cuttack Mahals and the northern portion of Nagpore. It is estimated to be 400 miles in length, by 280 in average breadth. Gundwana, in its most extensive sense, includes all that part of India within the above-mentioned boundaries which remained unconquered by the Mohammedans up to the reign of Aurungzebe. But Gundwana proper is limited to four districts, named Gurrah-Mundola, Chotees-Gundwana, Nagpore, and Chandah, and it stretches S. along the E. side of the Wurda and Godavery, to within 100 miles of the mouth of the latter. The greater part of this province is a mountainous, unhealthy, and ill-watered country, covered with jungle, and thinly inhabited; and to its poverty and other bad qualities its independence may be ascribed. A continued chain of moderately elevated hills extends from the southern frontier of Bengal almost to the Godavery, and by these the eastern was formerly separated from the western portion of the Nagpore dominions. This province contains the sources of the Nerbudda and the Soane, and is bounded by the Wurda and Godavery; but a want of water is still the general defect, the streams by which it is intersected, namely, the Mahanuddly, Caroon, Hatsoo, and Silair, being inconsiderable, and not navigable within its limits. The Goonds, or the hill tribes, who took refuge in the mountains and fastnesses from the invaders of the country, are the original inhabitants of the country, and still retain all their primeval habits of barbarism. The country which they inhabit is a mere wilderness, its inhabitants scarcely rising above the level of beasts. Their habits are loose and disorderly, and they frequently descend from the mountains which they inhabit to plunder the plains below, from which they were originally driven. In the course of the last century they have acquired an increasing appetite for salt and sugar, and the desire to procure these articles has operated as a stimulus to their industry, and tended more than any other circumstance to promote civilization amongst them. These Goonds are Hindus of the Brahminical sect; but they retain many of their impure customs, and abstain from no flesh except that of the ox, cow, and bull. The more fertile tracts of Gundwana were subdued at an early period by the Bhoonsla Mahrattas, who claimed as paramount over the whole. The inhabitants were rendered nominally tributary; but it was found impossible to collect any revenue from them without a detachment, so that in fact the collection of the revenue was rather like a plundering expedition, the cost of which always exceeded the profit. During the war against the Pindares in 1818, when the British troops invaded the territories of Appa Saheb, the Rajah of Nagpore, their operations were greatly facilitated by the insurrection of the hill tribes, who occupied the passes into the Nagpore territories. For a long series of years it was the policy of the rajah of this territory, a descendant of Sevajee, to interfere as little as possible with the neighbouring powers. At length, in 1803, Ragojee Bhoonsla was induced, in an evil hour for himself, to depart from this system of neutrality, and to join Scindia in a confederacy against the British. He was soon reduced, however, by the defeats which the confederates sustained at Assye and Argaum, to sue for peace, as the price of which he ceded a large portion of his dominions to the conquerors, namely, the province of Cuttack, including the pargunmah and port of Balasore. After the death of this rajah, whose sole object seemed to be to amass treasure, and who, for this purpose, laid the country under heavy contributions, and even joined with the Pindaree plunderers, the throne, contested by various competitors, was at last secured by Appa Saheb, his nephew, who, in the war against the Pindares, joined the coalition against the British power, and was involved in ruin along with his other allies. A treaty of peace was concluded with him, which he violated; and he was finally deposed in 1818, and the grandson of the late rajah put in his stead. The latter prince, after a reign of 35 years, died in 1853; and leaving no issue, the dynasty became extinct, and the kingdom of Nagpore was incorporated with the British empire. The term gun-making is applied to the manufacture of small arms generally—including the fowling-piece, the musket, the rifle, and the pistol. The rifle, being an arm of peculiar construction, and having properties distinct from those of other fire-arms, is treated separately. (See Rifle.)

The parts of a gun are the barrel, the lock, the stock, and the furniture.

1. Of Barrels.—Gun-barrels being made for various purposes and for different classes of purchasers (some of whom are willing to pay the highest price for the most perfect weapon, while others desire the cheapest article), vary considerably in the quality of their material, the mode of their construction, and the amount of labour expended on them. The material is in general iron, but steel is used to some extent in the preparation of the best and highest-priced barrels for sporting guns, and also, in the form of cast-steel, for a new species of rifle-barrel that has been used in America with the greatest success, and which recently has been introduced into this country both at Birmingham and Glasgow.

In the selection of iron for barrel-making, two qualities are absolutely essential—tenacity and elasticity. The first that the barrel may not burst under the explosive action of the powder, which does not expand gradually, but strikes suddenly like a hammer; the second that the barrel may not bulge, and also that it may preserve a certain sharpness of reaction requisite for the good shooting of the piece. It is therefore of the first importance that the iron should be of the best description that can be procured. Common iron, such as is used for the heavier works of ordinary manufacture, is so large and loose in the grain, that it could not stand the shock of explosion; and the gun-barrel makers from an early period have made strenuous endeavours to improve the quality of the metal, which in their hands has been brought to a higher state of perfection than in any other art. The finest iron ever used in this or any other country has probably been produced by the gun-makers in their attempts to work the metal up to its limits of excellence. The more iron is drawn out and forged under the hammer the more its quality improves, provided it is not burnt; and this circumstance induced barrel-makers to select the materials that had already undergone the utmost amount of work by fire and anvil. Hence arose the manufacture of gun-barrels from stubs or horse-shoe nails, which were not only made from rods of the best iron, but heated and hammered into their peculiar form, and afterwards cold-hammered to render them smooth, and to give the turn to the point which brings the nail out of the hoof. The stub was therefore the article that had most hammering expended on it, and was the best material for the manufacture of gun-barrels. So great was the superiority of the iron, that since stubs have ceased to be employed—either from the scarcity of the nails, or from the fact that inferior metal was employed in their manufacture—the efforts of barrel-makers have been directed to the production of an iron that should equal the stub; it being considered the standard of excellence to which all iron employed for good barrels should be made to approach more or less nearly. The barrels of the best sporting guns are now made of a mixture of iron and steel, which passes under the name of laminated steel. These barrels are of excellent quality, and shoot better than iron barrels on account of the elasticity of the metal.

When the iron is selected, whether of ordinary or superior quality, it is clipped by a pair of shears worked by steam into pieces the size of stubs. These are then washed to remove dirt, and cleansed in dilute acid to remove rust. They are then placed in a drum which revolves rapidly on a shaft, and the pieces are rolled and tumbled over each other till they become as bright as silver. They are now carried to the air-furnace, where they are heated almost to a state of fusion, so that they adhere together into a ball called a bloom of iron. From the furnace the ball, weighing about 40 lbs., passes to the forge-hammer, where it is drawn into a bar; and the bar then passes to the rolling-mill, where it is reduced to the requisite size for the manufacture of the barrels.

Iron barrels in Britain being made exclusively at Birmingham, we describe the process as at present practised by the Birmingham forgers. When the forge fire is first lighted it will not make what are termed best barrels. It requires to be burning and at work for several hours before it comes into working order for the fine twist barrels, and consequently the men begin by welding a number of the commonest and cheapest barrels. To each fire there are three men, the foreman and two assistants. They begin by making rolled barrels, which are the simplest in construction and most common in quality. A rolled barrel is merely a strip of iron folded up lengthwise like a boy's pea-shooter, and welded along the joint. The fore-part of the barrel, however, being required of less thickness than the breech end, these barrels are usually made of two lengths or tubes. The strips or plates of iron are heated and beat in a groove until they form a tube half closed. They are then heated again and closed with the edges overlapping. The edges are then welded on a mandril, and when a certain number of pieces are prepared the men proceed to weld together the two pieces of each barrel. The end of the breech part is opened a little on the beam of the anvil, the end of the fore-part is introduced, and the joint completed.

The fire being in proper order for the finer kinds of work, the welders proceed to forge twisted barrels, which differ from plain barrels in the circumstance that the grain of the iron, instead of running longitudinally, runs diagonally across or round the barrel, making a more perfect, stronger, and safer tube, neither so liable to burst nor to bulge. If we take a strip of paper half-an-inch broad and roll it diagonally round a ruler, we have a representation of the construction of a twisted barrel; and the joint that is welded, instead of being straight from end to end of the piece, is a spiral that makes a certain number of turns, according to the breadth of the rod of iron employed in the process. For the finest barrels the rod is nearly square, being \( \frac{3}{8} \)ths of an inch in breadth, and \( \frac{3}{8} \)ths in thickness. For very common barrels the rod is rather a ribbon of iron, being an inch or more in breadth. The latter will make only six turns in six inches of length, the former will make about fifteen or sixteen turns in six inches. The one makes a diagonal or open twist, the other a transverse or close twist; and in general the quality of a barrel may be ascertained by observing whether the twist be close or open, as only the best materials and the best workmanship are employed on the closest twisted guns.

The welders now take a rod four feet long and turn it into the form of a corkscrew (except that the turns lie close together), by means of two iron bars, one fixed and the other loose, the loose bar having a notch to receive the end of the rod. When inserted, the bar is turned by a handle until the whole of the rod is twisted, leaving a short end on which to weld a new rod. A sufficient number of pieces being prepared, the piece intended for the breech end is heated to a welding heat for about three inches, and jumped close by striking the end on the anvil. It is then hammered in a groove to make it round. One piece being welded, another is joined on by a single stroke of the hammer. The process continues till the barrel is of the required length, when it is again heated, a mandril introduced, and the tube is hammered in a groove. When cold, it ought to be cold-hammered to condense the iron and give the close grain that produces elasticity.

A patent has recently been taken out for making twisted barrels by machinery. A strip or ribbon of iron is first taken, bevelled at the edges, and slightly concave on the under side. This strip of metal is coiled round a mandril and welded at one heat, and the process combines rapidity with economy. Best barrels, however, are still made by the hand-hammer.

The plain barrel and the twisted barrel are those most commonly in use—the former for military and export purposes, the latter for sporting purposes. But another kind of barrel is made, being a combination of both. This is called the plated barrel, and is used for heavy rifles. Twisted iron being dearer than plain iron, the plated barrel has only a thin ribbon of twist rolled round a plain tube. If well made it is quite safe, and is perhaps as good for a rifle as if the twist were through the whole thickness of the metal; but it is to some extent an imposition, at least when sold as a genuine twisted barrel.

The Damascus barrel, so attractive from its handsome appearance, is made of iron and steel. Alternate bars of iron and steel are placed on each other in numbers of six each, after which they are rolled into rods 3ths of an inch square. The rods are heated throughout their whole length, and the two ends put into the heads of a description of lathe worked by a handle. It is then twisted like a rope, or, as Colonel Hawker says, wrung as wet clothes are. Three of the rods are then placed together, and welded with the twists or figures running in opposite directions, and from these rods the barrel is welded in the same manner as a twist barrel. The Damascus barrel is beautiful in figure, and shoots well, but is greatly inferior in strength to the stub or best iron barrel. It is much used on the Continent for double rifles and for the double guns with one barrel rifled, but in Britain it has ceased to be esteemed, except for a few fancy articles.

Boring of Barrels.—When a barrel is forged and welded it is taken to the boring-bench and secured on a sort of carriage that can travel the requisite length. A boring-bit of suitable size is fixed into a revolving spindle, and the point introduced into the end of the barrel. The bit is worked by steam, water, or hand, and is pressed forward by a weight until it has passed through the tube. During this operation a stream of water plays on the barrel to keep it cool. Bits of larger size are then used till all the blacks and scales are bored out, and the tube rendered of the proper calibre. (See BORING).

From the boring-bench it passes to the grindstone. The stones are of very large size, and revolve at a terrific rate; and the workmen have a method of allowing the barrel to turn in their hands at half the rate of the stone. By this means they produce a fine surface, and remarkable accuracy of form. Best barrels are turned after being ground; inferior barrels are struck up with a large smooth or fine cut file. They are then tapped in a temporary way, the proof-plug screwed in, and in that form they are sent to the proof-house. The London proof-house, however, requires the barrels to be fitted with their permanent breeches, and double barrels to be soldered together.

When barrels are turned they are fixed in the lathe—usually self-acting—by means of plugs or mandrils, made perfectly true, and of various diameters, to fit different bores. These are placed on the centres of the lathe, and a carrier is fastened on the plug that projects from the breech end of the barrel. The leading screw that travels the slide-rest is then set at the angle to which the barrel is to be turned, and the tool proceeds until the whole exterior of the tube is finished.

The next process is breeching, of which there are three kinds—common-plug breeching, chamber-plug or mortar breeching, and patent breeching. The first is used for the plainest and cheapest guns. The second is a slight improvement on the first, and consists in making a small ante-chamber in the body of the plug, so that the grains composing the main body of the charge of powder may be ignited simultaneously. These breeches are neither so convenient, nor do they generate as much force as the patent breech. They are screwed to the stock instead of being hooked to the break-off; and consequently the barrel cannot be removed from the stock without considerable trouble. The patent breech, the invention of Mr Henry Nock, is one of the greatest improvements ever made in fire-arms, and is the only form of breeching suitable for fowling-pieces and other guns of a superior description. Its great advantage is its superior strength and neatness; and the circumstance that the touch-hole, whether for a flint or percussion gun, passes into the solid breech, and not through the breeching-screws. It also permits the barrel to be removed from the stock by the sliding of a single bolt, which can be withdrawn by the finger.

Double Barrels.—Double barrels are made of two single barrels, flattened a little by the file on one side, and soldered together, with a rib on the top-side, along which aim is taken, and a rib on the under-side, to which the pipes for the ramrod are attached. Some makers have had a practice of brazing the breech-ends of double guns for about five or six inches; but this practice is altogether to be condemned, as the heat required for brazing is so great that it softens the metal, and deprives it of the elasticity and density produced by hammer-hardening. The other portion of the jointing being effected by soft solder, there is also a danger that the solder does not come perfectly up to the brazed portion, and that the barrels may rust away in a place that is out of sight, and perhaps may ultimately burst in consequence of the defect. The patent breeching of a double gun is an extremely ingenious piece of work. The breech of the left barrel, after being tapped, is screwed into its place, and a cutting tool with a directing plug is introduced into the right barrel. The tool is then turned either by a lathe or brace, and removes the metal so as to form the concave breech. The other breech is then turned to the exact size, and forms the cylindrical or convex breech.

The Proof of Barrels.—Whatever care may have been taken in the forging of barrels, it is requisite that they should undergo a proof before use, as defects may exist which are imperceptible to the eye. This is done under the authority of the government—an act of parliament having been passed in 1813, and another in 1815, to insure the efficient proving of barrels, and to inflict penalties on any maker who should "rib, stock, or finish a barrel that has not been duly proved." The proof-houses are situated at London and Birmingham, and to these two establishments all barrels must be sent, with the exception of those belonging to the East India Company, which has a proof-house of its own in London. A recent and most judicious regulation requires that barrels should be proved a second time, when percussioned, as serious accidents are supposed to have arisen from makers reducing the barrels by re-boring them after they had been proved and stamped. The proof consists in firing the barrels with a very heavy charge of powder, over which is a wadding of paper, then a leaden ball to fit the bore, then another wadding of paper. If the barrels burst, bulge, or exhibit any perceptible flaw, they are at once rejected; if not, they are washed in the water, impregnated with saltpetre, in which former barrels have been washed. They then stand for a day, and cracks or fissures become apparent by the saltpetre crystallizing on the defective weld. The Birmingham makers have an ingenious plan of filing out a crack, and hammering in a piece of wire to conceal the defect, and such barrels are sold at a lower price.

The following table exhibits the proof charges of powder for the respective calibres:

| Proof Scale | |-------------| | No. Balls to the pound | Weight of Powder for proof | No. Balls to the pound | Weight of Powder for proof | No. Balls to the pound | Weight of Powder for proof | No. Balls to the pound | Weight of Powder for proof | |---------------|--------------------------|------------------------|--------------------------|------------------------|--------------------------|------------------------|--------------------------| | No. 1 | 11 0 | No. 11 | 1 0 | No. 21 | 0 9 | No. 31 | 0 7 | | 2 | 5 5 | 12 | 1 0 | 22 | 0 9 | 32 | 0 7 | | 3 | 3 8 | 13 | 0 15 | 23 | 0 9 | 33 | 0 7 | | 4 | 2 11 | 14 | 0 14 | 24 | 0 8½ | 34 | 0 7 | | 5 | 2 2 | 15 | 0 14 | 25 | 0 8½ | 35 | 0 7 | | 6 | 1 12 | 16 | 0 13½ | 26 | 0 8½ | 36 | 0 7 | | 7 | 1 8 | 17 | 0 13½ | 27 | 0 8½ | 37 | 0 7 | | 8 | 1 6 | 18 | 0 12 | 28 | 0 8¼ | 38 | 0 6½ | | 9 | 1 2 | 19 | 0 11 | 29 | 0 8¼ | 39 | 0 6½ | | 10 | 1 1 | 20 | 0 10 | 30 | 0 7½ | 40 | 0 6½ |

The powder used is the best round granulated government powder.

Gun Locks.—Next in importance to the barrel of the gun is the lock, which has undergone many successive improvements, and has now arrived at a state of remarkable excellence and efficiency. It commenced as the match-lock, still used by some of the eastern nations, was improved into the wheel-lock, which generated sparks by the revolution of a notched wheel of steel, then became the snaphance, which is the foundation of the common flint-lock, was then changed into the ordinary flint-lock, with a single hammer and pan; and finally has resulted in the percussion-lock, which ignites the charge by means of a copper cap containing detonating powder. The percussion-lock has so completely superseded the flint that the latter may be termed antiquated; and, though still used, is no longer manufactured. It is unnecessary, therefore, to describe more than the percussion-lock. The merit of applying detonating powder as a substitute for flint in the discharge of firearms belongs to the Rev. Mr Forsyth, minister of Belhelvie, a parish in Aberdeenshire. Fig. 1 is a representation of the original percussion-lock. It is ingenious; and if it would work with safety and efficiency, would be even preferable to the lock used in the present day; but it is unsound, and liable to accidents. It has a magazine, \(a\), for containing the detonating powder. This magazine revolves round a roller, \(b\), the end of which is screwed into the breech of the barrel. A small hole is opened in the roller, through which the priming-powder passes. This hole communicates with a channel which leads to the chamber of the gun. Right above the little hole in the roller is the pan for containing the priming. The magazine is provided with a steel punch, the under end of which is right above the pan, ready to ignite the priming when struck on the upper end by the cock, \(d\), in firing the gun. When the punch is struck down into the pan it is raised up again to its former position by a spiral spring. Every time the gun is fired the magazine is turned round, so as to drop a priming of detonating powder into the pan. It is then turned back again, and the steel punch is found in the position ready to fire the gun when the trigger is drawn. The defect of this lock was, that the magazine containing the detonating powder was apt to explode; but if the principle could be carried out with safety it would form a self-priming lock—a great desideratum both for military and sporting purposes.

Another form of lock, called the tube-lock, fired the charge by means of a tube containing detonating powder introduced into the side of the breech. Another form was the patch-lock, which gave fire by means of a patch of detonating powder on the face of the hammer. Another form, used in America, gave fire by means of a small globe of detonating powder crushed into the touch-hole, and struck by a steel point. All these forms, however, have given way to the copper cap, which appears to have the suffrages of all the best gun-makers. Other forms must at present be regarded rather as fancy articles than as belonging to ordinary gun-making.

Fig. 2 represents one of the best British locks, as received by the gun-maker from the lock-maker—the hammer being afterwards supplied by the former in making up the gun. Fig. 3 represents the separate pieces of the same lock, technically called the works. A, the lock-plate; B, the... tumbler; C, the bridle; D, the swivel; E, the main-spring; F, the sear, on the projecting branch of which the trigger acts; G, the sear-spring, which resists the pull of the finger, and keeps the sear in the notch of half-bend or full-bend. Fig. 2 represents the pieces in position when the hammer is down. This is termed a bar-lock, on account of its being fitted under a projecting bar at the breech end of the barrel. The works, however, may be partially reversed so as to place the lock in the hand of the stock, in which case the lock is termed back-actioned. The back-actioned lock was popular some years since; but the general opinion of makers and sportsmen seems to have decided so completely in favour of the bar-lock, that no other is now made in the ordinary way of business.

Very common locks, such as those applied to the old muskets, were made with a hook instead of a swivel. Such locks have a dull, heavy action, and never work with the lively motion of the swivel-locks. The swivel, although apparently a mere means of connecting the main-spring with the tumbler, is a very important part of the mechanism. If well hung, it has the effect of making the heaviest pull or greatest force of the main-spring—not when the hammer is on full-bend, as might be supposed from the circumstance that the more a spring is bent the greater its force—but when the hammer is down on the nipple. This, in fact, is one of the principal tests of a well-made lock; and an experienced finger will at once detect a bad lock, from the mere circumstance that the pull increases instead of decreases as the hammer is drawn up. For military purposes it has not been customary to use the swivel-lock, except for the most recently-made rifles; but it is poor economy on the part of the government to arm a soldier with an inferior weapon, when the extra cost would not amount to more than a couple of shillings for each musket or rifle.

Some locks, especially those intended for rifles where a hair-trigger is used, have a detant—that is, a small piece of moveable steel attached to the tumbler in such a way that when the lock is on half-bend the detant lies behind the point of the sear. When the lock is on full-bend the detant lies in front of the sear, and projects beyond the half-bend notch, so as to carry the sear clear of the notch even if there be no pressure on the trigger. With a detant the lock cannot be let down from full to half-bend without being let down past the notch, and drawn up again—an advantage which insures that the sear shall be securely inserted into its proper place, and shall not hang on the edge of the notch, where it might slip and produce accidents. The detant is not generally used for sporting fowling-pieces, but it has advantages even for those guns.

Many safety-locks have been invented, in the hope of obviating the distressing accidents caused by the improper use of fire-arms, but not one has ever obtained the approbation of the mass of sportsmen or gun-makers. The true safety-lock is caution. Habitual caution in the use of arms is preferable to any mechanical device, which, while inefficient in the hands of a careless bungler, has the additional disadvantage of inducing the want of caution. All sorts of complicated devices are to be avoided in fire-arms. Those who use them must learn that the only security from accident is the most careful and constant prudence, and the habitual conviction that caution must never be relaxed. The practice of caution can be acquired by attention, and it is one of the first requisites of all who handle arms. A ship of war, for instance, is filled with the most tremendous materials of destruction, yet very few accidents occur, even in the gigantic navy of Great Britain. The reason is that one and all are taught habitual caution—systematic prudence reduced to one of the ordinary rules of life. So it should be with the sportsman; and no man ought to be trusted with arms who cannot acquire an intelligent and vigilant habit of using his weapon with careful prudence. What are termed self-acting safeties are, in general, devices, not for obviating accidents, but for extending the reputation or traffic of the inventor. A common bolt, however, which can be moved by the finger, and which checks the lock by bolting into the back of the tumbler, is a simple and useful appliance, and might be more generally used. In crossing a fence, jumping a ditch, or passing through a hedge—the occasions on which accidents frequently occur—the bolt prevents the discharge of the gun. Sportsmen do not generally use the bolt, except to rifles. In this perhaps they err, as it may safely be affirmed that bolt-locks would have prevented many of those accidents caused by twigs catching the triggers, or by some impediment coming in contact with the hammers that have improperly been left down on the caps, when, if they are not forced up to the half-bend, the gun is fired, and perhaps a catastrophe takes place. The disadvantage of the bolt is, that if the sportsman neglect to unbolt his lock, and a bird rises, he pulls hard, and risks breaking the sear. On the whole, however, the balance is in favour of the bolt, which is the only safety appliance that can be thoroughly recommended for general use. At the same time it is quite possible that a simple safety-lock may yet be devised; and, perhaps, this desideratum may be found in some method of locking the trigger in such a manner that the cheek shall be relieved at the moment of firing. There have been plans of this kind, but too complicated for general use.

The trigger, although not a constituent portion of the lock, is connected with the lock mechanism. The plain trigger is merely a piece of iron or steel hung upon a pin so as to press up the branch of the sear and relieve the tumbler. The introduction of a slight spring called the trigger-spring was one of the refinements which have now brought the best British guns up to such an admirable state of perfection. This spring prevents the triggers from hanging loose or rattling, and it brings them forward to the finger. Much of the excellence of a fowling-piece depends on the manner in which the triggers are hung.

The hair-trigger, used for pistols and rifles, is a construction by itself, and when well made is a remarkably neat piece of mechanism. Its object is to discharge the gun with the slightest possible pressure of the finger on the trigger. It can be made to any degree of fineness, and is called a hair-trigger, because, when finely set, a single hair will discharge the piece. It is then, of course, dangerous, as a jar or shake might produce an accident. It requires the most careful manipulation, and at all times is rather a critical appendage to fire-arms. Above all, it requires to be well made, an inferior hair-trigger being positively worthless. No part of a gun requires more perfect materials and workmanship, and therefore every purchaser of a weapon fitted with a hair-trigger should make sure that it is a good one. There can be no doubt that the hair-trigger is an advantage for rifle-shooting, where extreme accuracy is required, and where the pull on the common trigger is apt to diverge the gun from the line of aim, but it is so delicate in action that it can only be used safely in experienced hands. The principle of a hair-trigger is to make a spring do the work of the finger—the spring being set beforehand, so that when we wish to fire we have only to detach the spring and it strikes up the sear. When we fire a gun we do not take a hammer in our hand and strike the percussion-cap; we draw up the hammer of the lock to full-bend, and the main-spring exerts the required force. And so with the hair-trigger, we first set its spring, and when we wish to fire, the spring relieves the tumbler and discharges the gun. Hair-triggers are made single or double. With the former there is only one trigger to the gun, which can be used either with or without the hair. To set it, we press it forward until it locks into a catch. With the latter there are two triggers, the foremost of which is the common trigger, while the other, nearest the hand, sets the hair. The advantage of the double construction is, that we can put the gun to the shoulder and direct the line of fire before setting the hair-trigger. The double trigger is most used on the Continent. In Britain the single is most in vogue.

Gun-Stocks.—Gun-stocks are made almost exclusively of the wood of the walnut tree, which appears to combine in a higher degree than any other wood the qualities of soundness, strength, durability, and beauty of appearance, without excessive weight, hardness, or brittleness. Other woods have been tried to a considerable extent, but the walnut holds its ground without a rival. Bird's-eye maple, rosewood, the root of ash, &c., may be occasionally used according to the fancy of a purchaser, but no wood except the walnut enters as a general material into the manufacture of gun-stocks. The English wood is considered preferable to the French or German, being closer in the grain, finer in the texture, and generally of a more handsome figure. Before Joseph Manton improved the manufacture of fowling-pieces, the stocks were made too short; and after he had designed a new pattern of sterling excellence, other makers fell into the extreme of length, and made the stocks absurdly long. The rule is for each purchaser to suit himself, without being overstretched by a long stock, or obliged to bend the head inconveniently to a short one. In Britain stocks are made plain; on the Continent they are frequently ornamented by elaborate carving sometimes of great excellence. The stocks of Lebeda of Prague are models of elegance; and as this system of ornamenting fire-arms was a national peculiarity, it is perhaps to be regretted that the French and Belgians are departing from their own style and merely imitating the English patterns. In the Great Exhibition there was a brace of pistols stocked in ivory, the carving of which alone would probably cost from £50 to £100. The Americans stock their rifles differently from the British. They use much less wood, thin off the butt, and do not now carry the stock forward under the barrel. The heel or end of the butt is also hollowed out to fit the arm, as the American rifle-shooters fire from the upper part of the arm, and not from the shoulder as is customary in Britain. A pistol-hand is a handsome, and perhaps useful addition to the gun-stock. A very experienced gun-maker informed the writer of this article that he had never seen a broken stock that had a pistol-hand. Musket stocks have not hitherto been made by machinery in Great Britain or on the continent of Europe, except in Belgium, where the experiment failed. In America they are made in the following manner:—A stock is taken in the roughly-sawn state, and placed in a machine, in which it revolves. This first machine cuts out the portions on which the banding is placed. The stock is then taken to another machine, which, by a revolving drill, cuts the groove for the barrel down to the breech, and at the breech a cutter squares the groove at a right angle. Another machine turns the hold of the stock; another drills out the portion where the lock is fitted; another cuts the placing for the trigger-guard plate. Other machines cut the placings for the rest of the furniture, and the stock is so far finished as only to require a slight rasping to complete it. The parts are thus so perfect that a lock taken out of a heap will fit any stock with sufficient accuracy for military purposes. Altogether, sixteen different machines are required for forming the stock, and the operation occupies about half-an-hour.

Gun-Furniture.—The portions of a gun other than the barrel, the lock, and the stock, are termed gun-furniture. They consist of the heel-plate, which covers the butt; the break-off, into which the breeching hooks; the trigger-plate; the trigger-guard; the hammers; the escutcheons and bolt which fasten the barrel into the stock; the cap or tip of the stock; the tops, worms, and caps of the ramrod; and the screws necessary to put the gun together. Iron furniture of the best quality is made under the hammer, but a large proportion of the inferior furniture is stamped, not forged. The stamped or pressed articles are used for cheap guns, but they never possess the strength and solidity of the forged work. In the manufacture of gun-furniture—a scroll-guard for instance—the forgers exhibit marvellous dexterity, and turn out the article so accurately shaped that it requires little more than to be cleaned up with the file.

Pistols.—Pistols, although not generally manufactured by the same parties, are made in much the same manner as guns, with this exception, that where they are made in pairs the two barrels are forged and bored in one piece, and afterwards cut through the middle. This method saves labour, and insures that the calibres of the two barrels shall be exactly similar.

The Gun Trade.—The manufacture of guns may be divided into two great branches. The wholesale trade, which includes military arms and the commoner classes of export arms, and the retail trade, which includes the fowling-pieces and rifles of an expensive character used by sportsmen. The wholesale trade is carried on almost exclusively at Birmingham, which is now the only place in Great Britain where gun-barrels are forged. Formerly fine barrels were made in London; but the metropolitan forgers found that they could not compete with the local advantages of Birmingham, and the manufacture of barrels has centred exclusively in the latter town. Gun-furniture is also made at Birmingham; and gun-locks, especially those of the best quality, are made at Wolverhampton, where the lock-filers have acquired a high reputation for the excellence of their productions. For military muskets it has hitherto been customary for the government to contract with the Birmingham makers; but a large establishment is now in progress at Enfield, where muskets are to be made by machinery, on the plan adopted by the American government, and introduced into this country by Colonel Colt, who manufactures his revolvers by machines not previously used in Britain, and which bid fair to revolutionize the wholesale manufacture of arms. Inferior guns are finished at Birmingham, and sent out for sale. They are retailed by ironmongers and other traders, who are not gun-makers, and have no knowledge of the quality of the wares further than the price they pay, and the character of the wholesale merchant from whom they purchase. Many of these guns are of fair sound quality, and may be used for boating and rough work, but many also are blemished, being made up from articles that have been cast on account of what are termed faults. A barrel, for instance, that has a crack in it will be mended by hammering in a small piece of wire, and neither the salesman nor the purchaser is able to detect the artifice. The fine or best-gun trade, which is carried on at London, Birmingham, Edinburgh, Dublin, and the provincial towns, is of an entirely different character from what is termed the sale-shop trade. The master gun-maker is here an artist, and not merely a salesman. He receives his barrels from Birmingham, his locks from Wolverhampton, and the furniture partly purchases from the forgers, partly makes at home. His business is to screw the gun together; but this technical term includes everything of importance, except the production of the raw material on which he works. He purchases the very best materials, as the price of these does not constitute nearly so large an item as the after-work to be expended on them. He subjects them to the closest inspection; and in proceeding to make up the gun he discovers the quality of every individual part. His position in the gun-trade is much the same as that of the British watchmaker who receives his materials from Clerkenwell, or of the Parisian watchmaker, who receives his from Geneva. The making of the watch is a different art from the making of the plates, wheels, and cases. And so with gun-making. The gun-maker is the artist who superintends the production of the finished work. This branch of the gun manufacture has rapidly increased within the last few years. A London gun was formerly esteemed as superior to all others; and in the days of Joseph Manton, Henry Nock, Durs Egg, &c., it was no doubt superior to any piece that was made elsewhere in Britain. But the making of fine guns has extended to almost every part of the kingdom, and Birmingham now produces sporting guns of the very best quality, while Edinburgh has become celebrated for the accuracy of its rifles, and for the extreme finish of its higher class of fire-arms. An Edinburgh gun is now in every respect equal to the best guns of the metropolis.

When guns are stocked and screwed together, their barrels are browned to prevent them rusting. There are several methods of browning, and each maker has little modifications of his own. The following is the recipe for the wash with which barrels are stained:

1 oz. muriate tincture of steel, 1 oz. spirits of wine, ¼ oz. muriate of mercury,

½ oz. strong nitric acid, ½ oz. blue-stone, 1 quart of water.

These are well mixed and allowed to stand a month to amalgamate. The oil or grease is carefully removed from the barrels by lime, and the mixture is laid on lightly with a rag or sponge every two hours, and scratched off with a steel scratch brush every morning until the barrels are dark enough. The acid is then quenched by pouring boiling water on the barrels. Inferior barrels are stained by a different process. Muriate of mercury is dissolved in a wineglassful of spirits of wine, and this solution is mixed with a pint of water. Some of the mixture is then poured on a small quantity of whitening, and laid on the barrel with a sponge; as soon as dry it is brushed off, and a fresh coat laid on. This is continued till the colour is dark enough, which is generally in about two days. Hot water is then applied, and the barrels are suddenly immersed in cold water to heighten the colour. Another method, called smoke-brown—although the colour produced was a greyish-black—was also employed, and is strongly recommended in Mr Greener's Treatise on the Gun; but it is not to injure the barrels unless performed with the utmost dexterity and care. It has therefore fallen out of use, except for a few rifle barrels. The plan is to anoint the barrels with a little vitriolic acid, which is then washed off, and the iron rubbed dry. They are then passed through the flame of the forge-fire until covered with a sooty covering, then allowed to stand in a damp cellar till rust is produced—after which they are scratched with the wire brush. The process is repeated until the colour becomes permanent. This stain looks well and stands well, but is not suited for general use.

In finishing a gun, the hammers, break-off, lock-plate, and breeches are case-hardened by the ordinary mode of case-hardening iron. The heel-plate and trigger-guard are blued, and the screws, which ought always to be of steel, are tempered. The stock is stained and oiled—or varnished and polished in the same manner as a coach panel. The latter mode best resists rain and moisture, and is to be preferred where the varnish is good. Few of the ornamental arts of this country have made more progress than that of gun-engraving. Where formerly there were merely a few scrolls and some rude attempts at a sporting dog or game bird, we now find the gun-furniture ornamented with elaborate work of the most tasteful design and most careful execution. As the British taste, however, rejects fanciful ornament, the engraving is almost exclusively in lines cut with the graver, whereas the Germans employ the method called cutting out, the ground being cut away, and the figures left in relief. The latter mode produces remarkably handsome work.

The American Rifle.—The American rifle having attained to great celebrity from the unusual accuracy of its fire, we may describe one of the most recent construction. It is rather remarkable that in the Great Exhibition of 1851 there should have been no specimen of this weapon publicly exhibited. The barrel is made of cast steel thoroughly annealed, and is cut or planed outside into an octagonal shape. The barrel is 2 feet 8 inches long, and is fitted with a loading muzzle—its weight ten pounds. The patent breech is made of wrought iron, case-hardened, and is joined to the break-off by a hook, with the addition of a half-lap joint secured by a square-headed screw. This mode of fastening does away with the wood in front of the breech. The false or loading muzzle is put on by means of four steel pins about ¼ inch in diameter, and ¾ inch long, and the holes for these pins are drilled before the muzzle is cut off. When the muzzle is cut it is held in its place by a cramp, and the rifling is cut through both muzzle and barrel. A small globe of steel is fixed on the upper part of the muzzle to prevent the front sight being seen when the muzzle is on the barrel, so that there shall be no danger of firing it away. The bore of the barrel is scarcely ⅛ths of an inch, or about 90 round balls to the pound. The conical balls called pickets are 43 to the pound. The bore is then worked out with lead and emery until quite true. It is then cut with a gaining or graduated twist, starting at the breech with one turn in 6 feet, and ending at the muzzle with one turn in 3 feet 6 inches. There are six cuts or creases, and the sides of the lands are cut square to their surface. It is then freed from the breech to within 1½ inches of the muzzle, so as to reduce the friction. The lock has back-action, and a single hair-trigger. The stock is of black walnut, straight from butt to break-off, and there forms a considerable angle with the barrel. A globe-sight is fixed into the stock just behind the break-off, and a bead-sight at the muzzle. The price of such a weapon in America is from 50 to 200 dollars. With such a weapon, and a telescope sight, Capt. W. Tisdale of Utica made ten consecutive shots at 220 yards, and each shot on the average measured less than one inch from the centre of the bull's-eye—the whole string being 9½ inches. The whole of the ten shots would have gone into a small-sized playing-card. A feat of this kind is probably unparalleled in Great Britain, and it may draw the attention of our own makers to the propriety of diminishing the calibre, and increasing the speed of the ball. The loading-muzzle used by the Americans is intended to prevent the wearing of the true muzzle; but the superiority of American rifle-shooting is rather to be attributed to the smallness of the ball, and the great velocity with which it travels. The greater the velocity the straighter is the flight—that is, the course of flight has less elevation and depression than when a heavier ball is used.

In the British service the old smooth bored musket is rapidly giving way to the new Enfield rifled musket, a weapon of tremendous power and range. This is the arm commonly spoken of as the Minie rifle, but it is no longer a Minie. Minie's principle was to introduce an iron cup into the butt of an elongated ball on the supposition that the cup being driven into the lead by the force of the powder, would expand it and make it fit the rifle-grooves, thereby procuring the advantage of loading without hammering or forcing the ball into the muzzle. The principle was excellent, and has wrought a revolution in the small arm department of the service, but the mode of carrying it out by means of the iron cup was defective. The cup was frequently driven not into but through the ball, leaving the lead in the barrel. It was then found that the iron was superfluous, and that if the lead was hollowed out or cupped, it would expand quite sufficiently. Such is the ball now in use for the military rifle, and Mr Pritchett received an award of £1,000 from government for its production.

The cost of these muskets as made by contract, has been Ls. 9½. 0½d. As made at Enfield the cost has been Ls. 4½. 7½d.; but if made by machinery, and an order given for 1,000,000, Col. Colt offered to supply them at 30s. In the opinion that this price was not too low, Col. Colt was borne out by Mr Anderson, chief engineer in the royal arsenal at Woolwich, and by the celebrated engineer Mr Nasmith. The contract price of the musket in the United States is from 10 to 12 dollars—from L2 to L2, 10s. The price at which the Belgian rifled musket is made in the government factory is 42 francs, and a musket of the same pattern could be made in this country at 36s. or 37s.

That the rifled musket used in the British service is one of the most powerful weapons ever invented in the department of small arms, is unquestionable; but it requires improvement. As made at present it has several drawbacks. After being fired even a small number of shots, it is so difficult to load that the men using it have complained that they could not send the charge home. From the method of stocking also it has been found impossible to draw the ramrod in wet weather. The pull on the trigger is considerably too great for accurate shooting, and the method of forging the sight-supports on the barrel instead of using a slide-sight prevents the guns from being correctly regulated. These are serious disadvantages, and they require the renewed attention of the military authorities. It is well known that a good sporting rifle can be fired 100 or 150 times without cleaning. It is therefore a reproach to the military weapon that 20 or 25 shots have been found to disable it. The guns, however, are of admirable workmanship, and only require some slight improvements to render them the best small arms in any service.

The following is the account of the sum voted by the House of Commons for the supply and repair of small arms in each year from 1842–43 to 1854–55, and of the sum actually expended.

| Year | Amount voted | Amount expended | |------|--------------|----------------| | 1842-3 | £1,180,000 | £1,114,600 | | 1843-4 | 136,000 | 118,936 | | 1844-5 | 90,000 | 111,336 | | 1845-6 | 84,379 | 117,317 | | 1846-7 | 120,000 | 135,277 | | 1847-8 | 120,000 | 134,789 | | 1848-9 | 140,000 | 139,365 | | 1849-50 | 120,000 | 122,885 | | 1850-1 | 90,000 | 88,979 | | 1851-2 | 76,000 | 37,654 | | 1852-3 | 78,000 | 61,639 | | 1853-4 | 135,800 | 28,931 | | 1854-5 | 161,400 | |

* This account is incomplete.

The following table shows the total supply of arms made in London for the Government and East India Company from 1841 to 1850. Since the latter date the government contracts have been almost entirely withdrawn from the metropolis, on account of a trifling difference in price; and the excellent body of workmen formerly assembled in London have betaken themselves to other trades or to other localities:

| Dates | E. India Company | Government | Total | |-------|-----------------|------------|-------| | 1841 | 20,150 | 7,660 | 27,810 | | 1842 | 36,333 | 12,926 | 49,279 | | 1843 | 34,880 | 12,270 | 47,150 | | 1844 | 25,362 | 13,496 | 38,858 | | 1845 | 49,622 | 12,539 | 62,162 | | 1846 | 39,139 | 10,339 | 49,478 | | 1847 | 67,214 | 18,378 | 75,592 | | 1848 | 55,068 | 23,862 | 78,930 | | 1849 | 71,381 | 26,366 | 97,747 | | 1850 | 26,025 | 13,697 | 39,632 |

Total of ten years, 584,376, or an average of 58,437 for each year.

Revolvers.—Among the arms recently introduced into this country and manufactured to a large extent is the revolver or repeating pistol. The principle is not new, as revolvers of a construction nearly similar to those now in use are to be found in the museums of old arms. To Col. Samuel Colt of the United States belongs the merit of reviving this species of weapon; and he has a patent, dated 1836, for his pistol, which is universally known as Colt's revolver. Messrs Deane, Adams, & Deane of London have also a patent for another form, which differs from Colt's in several essential particulars. Revolvers have long been made in this country, but they were made of a large mass of metal bored into the required number of barrels, the whole of the barrels being of the same length. This weapon was so clumsy as to be almost useless. The new revolver is made with one single barrel of the full length, and a revolving chamber only long enough to contain the charge, and bored into five or six compartments. This chamber is made of cast steel, and is so fitted that it can be removed by drawing a bolt. This gives the advantage of enabling a spare chamber to be used, which can be kept ready loaded, and the number of shots is thus doubled. With a 5-shot pistol and two chambers 10 shots can be fired without re-loading. In introducing the revolver in America, Col. Colt expended a very large amount of money without reaping a return until 1849-50, when the disturbed state of Florida and Texas, and afterwards the Mexican war, established the reputation of his arms. In his evidence before a select committee of the House of Commons in 1854, he mentioned the curious fact that, while he was supplying the American government with pistols at 25 dollars each, the soldiers were selling them to traders at 75 to 150 dollars, and sometimes as high as 200 dollars each. He has now a manufactory at Hartford, in America, where, in 1853, he turned out about 50,000 revolvers; and another manufactory at Vauxhall, London, where he employs between 200 and 300 workmen, and where he could produce nearly 1000 pistols per week, made almost entirely by machinery. The difference between a Colt and a Deane & Adams pistol is, that the Colt has a lever ramrod under the barrel, which is part of his patent, and that the hammer requires to be drawn up every time the pistol is fired. The Deane & Adams, on the contrary, has a lever at the side, and can be fired by merely drawing the trigger. A recent improvement of Mr Adams has produced a pistol that will fire either by drawing up the hammer or by pulling the trigger, and this pistol is considered the most perfect that has hitherto appeared. Another form, and one of great merit, has a spur under the trigger-guard, and the arm can only be fired when the spur is pulled by the middle finger, while the trigger is pulled by the fore finger. Between the merits of these weapons it is difficult to institute an impartial comparison. It may, however, be laid down as a general maxim, that every pistol that will fire by merely drawing the trigger is a dangerous weapon. The trigger may be drawn by accident, as in the case of the late lamented Dr Hector Gavin, who was shot by one of these weapons, to the regret of the service and the nation. It may perhaps be said, however, that Colt's pistol is more safe in its construction—Deane and Adams's more effective in competent hands. But all the revolvers require to be handled with caution.

Another objection to any arm that fires merely by the draw of the trigger is, that if the main-spring be strong enough to explode the percussion cap with certainty, it becomes too strong for the finger, and the shooter swerves from his aim. If, on the contrary, it is so weak as to pull easily, there is no certainty that the cap will explode except under the most favourable circumstances. In very dry weather, and with good caps, it may explode every time it is struck by the hammer; but in damp weather, or with inferior caps, the arm misses fire, and the shooter is disappointed, or it may even be that his life is endangered. There is thus a compensation of advantages in each weapon, and a selection must be made according to the purpose for which the arm is intended. Repeating rifles, on the same principle as the pistols, are manufactured and used in the United States, but they have not yet been adopted in Britain.

(P. E. D.) GUNNERY

Gunnery. Is the art, in a restricted sense, of determining the motions or ranges of projectiles discharged from cannon, mortars, howitzers, and other kinds of artillery; and, in a more general sense, of determining not only the motions of such bodies, but also the arrangements by which they are rendered effective instruments of war.

I.—THEORY OF GUNNERY.

The use of fire-arms had been long known before any theory concerning them was attempted. Nor is this remarkable, as the theory of the motion of projectiles depends on a knowledge of certain laws of nature which were not discovered till many years afterwards. It was different as regards the improvement of those defensive arrangements which had been found sufficient in the earlier times to afford protection against the more ancient engines of war, or, on the other hand, to cover those who were called upon to use them. The architects of the middle ages (see Fortifications) quickly saw the necessity of modifying the forms and proportions of the ancient walls which then surrounded fortified towns, and rendering them more suitable both for the use and for the resistance of the newly-discovered artillery adapted for the use of gunpowder. The Cavaliere Saluzzo of Turin has indeed shown, from the archives of his native town, that Giorgio Martini, Architetto Senese, undertook the task of remodelling the ancient walls of castles and of towns even before the commencement of the sixteenth century, as Martini died in 1506. In his plans the profiles of the old castle are not much altered; but the trace is greatly modified, so as to produce a more perfect reciprocal or flanking defence, either by a combination approximating to something like the bastioned trace, or by capannoni—so called from their resemblance to a woodman's hut—in the ditch, a work in principle the same as the caponnières subsequently invented by Dürer. Nothing, perhaps, is more calculated to exhibit the military spirit which pervaded the Italian architects, sculptors, and others, as well as those of the military profession, than the list of Italian authors on the art of war, in the corps papers of the Royal Engineers, which was drawn up by an accomplished lady, Mrs Lennox Conyngham, from an inspection of the libraries of Rome alone. In that list appears the name of Nicholas Tartaglia, who was the first author who wrote professedly on the flight of cannon-shot. In 1537 he published a book at Venice, entitled Nova Scientia; and afterwards another, printed at the same place in 1546, in which he treats of these motions. His discoveries were but few, on account of the imperfect state of mechanical knowledge at that time. He determined, however, that the greatest range of cannon was with an elevation of forty-five degrees; and he likewise ascertained, contrary to the opinion of practitioners, that no part of the track described by a bullet is a right line, although the curvature is in some cases so small that it is not attended to. He compared it to the surface of the sea, which, though it appears to be a plane, is yet undoubtedly incurvated round the centre of the earth. He also assumes to himself the invention of the gunner's quadrant, and often makes shrewd guesses as to the results of untried methods. But as he had not opportunities of observing practice, and founded his opinions solely on speculation, he was condemned by most of the succeeding writers, though often without any sufficient reason. The philosophers of those times also intermeddled in the questions which hence arose; and many disputes on motion occurred, especially in Italy, where they continued till the time of Galileo, and probably gave rise to his celebrated Dialogues on Motion. These were published in the year 1638; but in the interval, and before Galileo's doctrine was thoroughly established, many theories of the motion of military projectiles, and many tables of their comparative ranges, at different elevations, were published; all of them egregiously fallacious, and utterly irreconcilable with the motions of these bodies. Many of the ancients, indeed, indulged in speculations concerning the difference between natural, violent, and mixed motions; but when they did so, scarcely two of them could agree in their theories.

It is strange, however, that during all these contests so few of those who were intrusted with the charge of artillery thought it worth while to bring these theories to the test of experiment. Mr Robins informs us, in the preface to his New Principles of Gunnery, that he had met with no more than four authors who had treated on this subject. The first of these is Collado, who has given the ranges of a falconet carrying a three-pound shot to each point of the gunner's quadrant. But, from his numbers, it is manifest that the piece was not charged with its customary allotment of gunpowder. The results of his trials were, that the point-blank shot, or that in which the path of the ball did not sensibly deviate from a right line, extended 268 paces. At an elevation of one point (or $7\frac{1}{2}$ of the gunner's quadrant), the range was 594 paces; at an elevation of two points, 794 paces; at three points, 954 paces; at four, 1010; at five, 1040; and at six, 1053 paces. At the seventh point, the range fell between those of the third and fourth; at the eighth point, it fell between the ranges of the second and third; at the ninth point, it fell between the ranges of the first and second; at the tenth point, it fell between the point-blank distance and that of the first point; and at the eleventh point, it fell very near the piece. The paces spoken of by this author are common steps.

The year after Collado's treatise, another appeared on the same subject, by one Bourne, an Englishman. His elevations were not regulated by the points of the gunner's quadrant, but by degrees; and he ascertained the proportions between the ranges at different elevations and the extent of point-blank shot. According to him, if the extent of the point-blank shot be represented by 1, the range at 5° elevation will be $2\frac{3}{4}$, at 10° it will be $3\frac{1}{2}$, at 15° it will be $4\frac{1}{2}$, at 20° it will be $4\frac{3}{4}$, and the greatest random will be $5\frac{1}{4}$. This last, he tells us, happens in a calm day, when the piece is elevated to 42°; but according to the strength of the wind, and as it favours or opposes the flight of the shot, it may be from 45° to 36°. He has not informed us with what piece he made his trials, though from his proportions it seems to have been a small one. This, however, ought to have been attended to, as the relation between the extent of different ranges varies extremely according to the velocity and density of the bullet.

After him, Eldred and Anderson, both Englishmen, published treatises on this subject. The first published his treatise in 1646, and gave the actual ranges of different pieces of artillery at small elevations, all under ten degrees. His principles were not rigorously true, though not liable to very considerable errors; yet, in consequence of their deviation from the truth, he found it impossible to make some of his experiments agree with his principles.

Before proceeding further with the history of gunnery, or passing the epoch at which the writings of Galileo had prepared the way for a sounder knowledge of its principles Gunnery. It is only an act of justice to Nicholas Tartaglia to record what he actually either knew or conjectured on the subject. The second of his works, published, as before stated, in 1546, was translated into English by Mr Cyprian Lucar, and published in London in 1588. It consists of three books of Colloquies concerning the Arte of Shooting; and the motive for writing it is thus stated by Tartaglia in his dedication of the book to King Henry VIII., in the language of Lucar's translation:—"It was never my profession, not at any time have I delighted to shoot in any har-chibuse, hande-gunne, or in any other small or great piece of artillerie, nor doe intende to shoothe hereafter in any of them; but one only question which a skillfull gunner in 1531 did aske of me in Verona provoked mee at that tyme to thinke thereupon, and by that occasion to finde out the order and proportion of shoothes or markes neare hand, and also at markes far off, according to the variable elevation of the piece which doth shoothe, whereof I should never have had any care, if that gunner had not with his saide question stirred me up to deale in the same." The idea having been thus raised in his mind, Tartaglia was stimulated by the threatened war with the Turks to publish, in 1557, a short Treatise of Shooting in Gunnery, to the end (as he observes) that my devises in the same might bee considered of. This book, he says, did no good; and as he continued to be asked many questions by men of station and learning, as well as by gunners, on the subject, he determined to answer all such queries in his second book, which is therefore arranged in the form of dialogues between Tartaglia and the Duke of Urbino, the Prior of Barletta, the Lord of Achaea, bombardiers, gunners, and gun-founders.

1. In the third Colloquie of the 1st Book he lays down as a proposition, that "a pellet doth never range in a right line except it be shot out of a piece right up towards heaven, or right downe towards the centre of the world."

In proving this proposition, Tartaglia assumes that the effective weight of the pellet, or ball, is diminished in proportion as the velocity is increased, and vice versa; and hence that the ball is less drawn to the earth at the first part of its flight than it is at the last. The explanation of the fact is therefore founded upon erroneous principles, but the reasoning from it is good; for Tartaglia says—

"If now it be supposed that in any portion AB of the trajectory of the ball, the ball moves in a right line, divide AB in two equal parts at E; now, as the velocity is greater in AE than it is in EB, the ball will be less urged to the ground in the first than it is in the second half, and hence that the line EB cannot be as nearly straight as AE; or, subdividing again AE into two parts at F, PE will be more removed from a straight line than AF; and so on—proving that no part of the trajectory could be absolutely straight." Considering the imperfect knowledge of the time, this demonstration was perhaps as much as could be expected, as it distinctly recognises the principle, that weight or gravity continued to draw the ball to the earth from the first to the last moment of its motion under the impulse of the propelling force, and hence that it could not at any moment move in a straight line.

2. Point-blank.—Tartaglia, in removing the scruples of his imaginary auditors, explains in the most satisfactory manner the different acceptations of this term, as now applied in the British and French service.

In this cut it is assumed that CD is, by a proper arrangement of sights at the breech and muzzle, made parallel to the axis of the gun; and hence, that the line of aim, CDE, is parallel to FG, or to the axis of the gun produced; in which case it is manifest that the ball could not arrive at G, but would come to the ground at I, which point, provided GI be equal to the height of the axis of the gun above the ground, marks the point-blank range of the British artilleryman, or the lateral space passed over by the ball in the time it takes to fall to the ground. For convenience sake, the axis is supposed to be horizontal, and the range is also taken on a horizontal plane.

If the sights are so arranged that one shall be higher from the axis of the piece than the other, the line of sight or aim will no longer be parallel to the axis, but, when prolonged, will make an angle with, or intersect it. If the muzzle sight be the higher, always estimating from the axis, the intersection will take place behind the breech, and the line of the axis will be depressed below that of sight; if, on the contrary, the breech sight be the higher, the intersection will take place in front of the muzzle, and the line of the axis will be elevated above that of sight. The latter is the case when the line of natural aim, or sight, is used, or that passing through the highest point of the breech-ring and the low sight, or highest point, of the muzzle-ring. The case is analogous to that of fig. 3, where FG represents the This is better shown in fig. 4, where the visual line CDL is represented horizontal—the axis, therefore, being elevated by the angle made by the intersection of the axis prolonged and the visual line. In this case, then, the ball rises and intersects the visual line at L, and again on its descent at L, proceeding on to N, so that the mark M would be struck if placed anywhere on the trajectory from L to N; and when the line CD is tangent at once to the muzzle and breech of the gun, or passes through any fixed and invariable marks or sights placed for the purpose on the summit of the base and muzzle rings, it becomes the natural line of aim or sight; and if placed horizontal, as in the figure, determines the point-blank range, or the distance from the gun of the second intersection L of the trajectory with the natural line of sight.

In the excellent treatise on artillery by Didion, chef d'escadron of the French artillery, the meaning of the term but-en-blanc, or point-blank, and the range corresponding to it, are stated as above, and, as observed by Didion, the point K of fig. 3, or I of fig. 4, being, from the ordinary construction of guns, so near to the muzzle (in a 68-pounder about seven feet), may be considered as corresponding with the actual point of intersection of the axis of the gun with the line of sight, the point of second intersection only being therefore of practical importance as determining the range.

It is very necessary to keep in view the two different interpretations of point-blank and point-blank range which have been here explained, in comparing the published ranges of English, as well as American and foreign guns, as will be perceived from the following statement:

Griffiths (Artillerist's Manual, 6th edition, 1854) gives—

"The point-blank range of iron 32, 24, 18, and 12-pounders, with solid shot, as varying from 380 to 260 yards;

Table of the Angles of Natural Aim or Sight of French Guns.

| CALIBRES | 36 | 30 | 24 | 18 | 16 | 12 | 8 | 6 | |----------|----|----|----|----|----|----|---|---| | Canons de siège et de place | ... | ... | 1° 15' 49" | ... | 1° 9' 4" | 1° 6' 31" | 1° 3' 45" | ... | | Canons de campagne | ... | ... | ... | ... | 0° 59' 39" | 0° 59' 46" | ... | ... | | Canons de côte | 1° 32' 0" | ... | 1° 28' 0" | ... | 1° 21' 0" | 1° 18' 0" | ... | ... | | Canons de marine (longs) | 1° 34' 17" | 1° 34' 0" | 1° 30' 37" | 1° 31' 37" | ... | 1° 25' 33" | 1° 11' 11" | 1° 18' 4" | | Canons de marine (courts) | 1° 56' 53" | 1° 57' 0" | 1° 49' 48" | 1° 50' 3" | ... | 1° 41' 5" | 1° 23' 53" | 1° 27' 15" | | Caronades | ... | 3° 40' 0" | 3° 50' 0" | ... | 3° 48' 0" | ... | ... | ... | | Canon-obusier | ... | 1° 10' 15" | ... | ... | ... | ... | ... | ... |

Now, Griffiths states the point-blank range of the 12-pounder iron, with 4 lbs. of powder, as 360 yards; and in the following table, it will be observed that the point-blank range of the French 12-pounder, a gun which would be equivalent to a 14-pounder English, is given as 650 metres, equal to 710 yards. In like manner Captain Mordecai gives the point-blank range of the 12-pounder American field-gun, with 2 lbs. 5 oz., as 347 yards; whereas the French 12-pounder... Gunnery, with a similar charge (see following table) gives 540 metres, or 600 yards nearly. The French point-blank range in the first case corresponds to an elevation of 1° of English practice, and in the second to an elevation of less than 1°, as Captain Mordecai gives the range of 1° as 662 yards, though the angle of dispart of the French siege 12-pounder is 1° 9' 4", that of the 12-pounder field-gun being 0° 59' 39".

Range Table of French Siege and Garrison Guns fired with different Charges.

| CHARGES | 0° 20' | 0° 30' | 0° 40' | 0° 50' | 0° 60' | 0° 70' | 0° 80' | 0° 90' | 1° 00' | 1° 10' | 1° 20' | 1° 30' | 1° 40' | 1° 50' | |---------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------|--------| | Canon de 24. | 600 | 376 | 284 | 216 | 168 | 132 | 104 | 85 | 68 | 56 | 48 | 40 | 32 | 24 | | Hausses pour les distances | 500 | 415 | 284 | 205 | 152 | 115 | 89 | 70 | 55 | 43 | 35 | 28 | 21 | 14 | | Portées de but en blanc | 400 | 322 | 207 | 141 | 101 | 75 | 56 | 40 | 30 | 21 | 14 | 10 | 7 | 5 | | Canon de 16. | 300 | 360 | 202 | 128 | 81 | 52 | 33 | 20 | 14 | 10 | 7 | 5 | 3 | 2 | | Portées de but en blanc | 200 | 230 | 109 | 57 | 28 | 9 | -3 | -13 | -20 | -25 | -34 | -43 | -45 | -47 | | Canon de 12. | 60 | 90 | 120 | 150 | 180 | 210 | 240 | 269 | 298 | 335 | 405 | 455 | 504 | 546 | | Portées de but en blanc | 80 | 120 | 160 | 200 | 240 | 280 | 319 | 356 | 390 | 449 | 500 | 545 | 585 | 620 | | Canon de 10. | 600 | 385 | 221 | 135 | 88 | 63 | 47 | 36 | 27 | 20 | 14 | 10 | 7 | 5 | | Hausses pour les distances | 500 | 315 | 185 | 94 | 60 | 41 | 27 | 17 | 10 | 4 | -3 | -8 | -12 | -16 | | Portées de but en blanc | 400 | 223 | 104 | 57 | 33 | 18 | 7 | -6 | -10 | -15 | -19 | -22 | -24 | -26 | | Canon de 8. | 300 | 140 | 62 | 25 | 8 | -3 | -10 | -14 | -20 | -23 | -27 | -30 | -32 | -34 | | Portées de but en blanc | 200 | 68 | 18 | 4 | -15 | -22 | -27 | -33 | -35 | -37 | -39 | -40 | -41 | -42 | | Canon de 6. | 109 | 162 | 214 | 265 | 314 | 360 | 400 | 436 | 468 | 523 | 567 | 608 | 650 | 690 |

This Table is for guns in perfect condition; when much used the hausses must be augmented. The Hausses-de-Mire corresponds to the tangent scale of British ordnance, the degrees being replaced by the natural tangents of the required elevations in millimetres.

The term dispart is of ancient use, and Lucar (1588) lays down as one of his maxims, that "every gunner, before he shootes, must trulle disparte his pecee, or give allowance for the disparte;" and when he dispartes a pecee, he ought to set the said dispart in the midst and uppermost part of metall over the mouth of the pecee," a caution equally necessary at the present day, as every gunner ought to make himself acquainted with the dispart of his gun, and with the range corresponding to it, and then familiarise his eye with that distance, which would thus become a base of comparison for ranges within and without.

3. Mode of action of gunpowder. Resistance of the air.—As the real nature of the products of combustion, as well as of combustion itself, is a comparatively recent discovery, the exact theory of its action was not to be expected from Tartaglia, and yet he gives a very reasonable account of it. In the 22d Colloque, in which a gunfounder inquires why guns generally burst at the breech, Tartaglia answers to this effect, that the great exhalation proceeding from the saltpetre acts against the ball, and as it is difficult to put it at first in motion, though easy to keep up the motion when once given, should the gun be too weak in that part it will yield to the force of the windie exhalation and burst; but if the metal be sufficiently strong, and the ball be moved, there will be no fear of bursting, unless by any accidental cause the motion of the ball be arrested, when the gun may burst, as it sometimes does, near the muzzle; "for, so soone as the pellet is in moving, that exhalation will continue with ease if no other let do happen, but so soone as the pellet commeth to the mouth of the pecee, it finds all the aire without the pecee, and by how much the pellet, together with the said exhalation that thrusteth it to assault the aire, commeth more swiftly, by so much the more united and with a greater force, doth the aire oppose itselfe very strongly to resist that sudden moving, and thereupon, in that place, another difficulite or strife riseth betwene the exhalations within (which thrusteth forth the pellet), and the aire without,—that is to say, the exhalation would goe out of the concavitie, and the aire without doth resist the same; but in the end, the exhalation within being of a greater force, and getting the victorie, breaketh forth and teareth in pieces his said enemies. And then the mouth of the pecee being, as it were, in the middest of the strife, doth alwayes suffer very much; and this is the cause that the pecee, lacking his due thickeenes on the said place, or for some other unknowne fault, doth there easily breake."

4. The length of the gun should be duly proportioned to the charge.—It had been supposed that the longer the gun the greater would be its range, but Tartaglia in the 11th, 12th, and 13th Colloquies, points out that though the long culvering of these days had a greater range than the shorter cannon, it required a correspondingly greater charge—that of the culvering being 4lbs of the weight of the shot, and that of the cannon only 3lbs; and further reasons, that for any given charge there is one length only which can give the maximum range, as if too short, part of the powder will be expelled before ignition, and so much power be lost; and if too long, the ball would be in the gun after the total ignition of the powder, and be checked in its progress by friction against the bore—the proper limit of length being that which will place the ball exactly at the mouth at the moment when all the powder shall be on fire, and the windie exhalation be at its maximum. "For on that instant all the expulsive vertue of the powder begins to worke on the pellet in the chiese of his furie or force, and after that vertue expulsive hath wrought on the pellet, the said pellet, finding nothing to let or resist his range (except the aire), will flie more farther than if the concavitie of the pecee had beene more longer or more shorter." Notwithstanding the partial imperfection of the reasoning, this was a curious approximation to the truth, as regards the exact proportion of the charge "for giving the maximum velocity" to the length: Gunnery.

of the gun; and though Tartaglia did not treat of the more general question of the inexpediency of increasing both charge and length beyond a certain point, he gave the explanation of the fact when he stated that the air resists the more, the more violent the action of the expulsive exhalation. Had he known the law of that resistance, he would have probably perfected the explanation by showing that ultimately the resistance would become so great as to require enormous strength in the gun to resist the concussion.

Robins (1742) explains the relation of the length of the bore to the charge and velocity communicated to the ball, by construction thus:—Let AB represent the axis of the piece; draw AC perpendicular to it, and to the asymptotes AB and AC describe any hyperbola LEF, and draw BF parallel to AC; find out now the point D where the rectangle ADEG is equal to the hyperbolic area DEFB, then will AD represent that height of the charge which communicates the greatest velocity to the shot; whence AD being to AB as 1 to $2^{7/1828}$, as appears by the table of logarithms, from the height of the line AD thus determined, and the diameter of the bore, the quantity of powder contained in the charge is easily known.

"If, instead of this charge, any other fitting the cylinder to the height AI be used, draw IH parallel to AC, and through the point H, to the same asymptotes AC and AB, describe the hyperbola HK; then the greatest velocity will be to the velocity communicated by this charge AI in the subduplicate proportion of the rectangle AE to the same rectangle diminished by the trilinear space HKE." This explanation depends upon the proposition relative to the determination of the velocity of the ball with a given charge to be subsequently referred to, but Robins' reasoning is here anticipated in order to place the result in opposition to that of Tartaglia.

Hutton (1812). In his tracts published in this year, Hutton details the experiments in gunnery carried on by himself and Major Blomfield, Royal Artillery (afterwards General Lord Blomfield), and other able artillery officers, for several years in the Warren, now arsenal of Woolwich. Some of these had been previously published in 1786 in a quarto volume of tracts, and a previous set, made in 1775, in the Philosophical Transactions for 1778—Dr Hutton having been awarded the annual gold medal of the Royal Society for his paper containing the results of the experiments, and the deductions drawn from them.

Some of these experiments were directed to the determination of the relation between the charge of powder, the length of the bore, and the resulting velocity. The experiments were made with five guns of the same calibre, being intended to discharge a ball of 16 oz weight, but of lengths varying from 30-3 inches to 82-3; the lengths of the bores varying from 28-53 to 80-80 inches, gun No. 5 being intended to be reduced in length by cutting off successive portions after a certain number of rounds of practice, so as to test the effect, on the velocity, of a variation in the length of the bore. The deductions are thus stated by Dr Hutton:—

"1st. The law determined by the previous experiments between the charge and the velocity of ball is again confirmed—namely, that the velocity is directly as the square root of the weight of powder, as far as to about the charge of 8 oz. (half the weight of the ball used); and so it would continue for all charges were the guns of an indefinite length. But as the length of the charge is increased, and bears a more considerable proportion to the length of the bore, the velocity falls the more short of that proportion.

"2d. That the velocity of the ball increases with the charge, to a certain point, which is peculiar to each gun where it is greatest; and that by further increasing the charge, the velocity gradually diminishes till the bore is quite full of powder. That this charge for the greatest velocity is greater as the gun is longer, but not greater, however, in so high a proportion as the length of the gun is; so that the part of the bore filled with powder bears a less proportion to the whole in the long guns than it does in the shorter ones; the part of the whole which is filled being, indeed, nearly in the subduplicate ratio of the length of the empty part.

"3d. It appears that the velocity continually increases as the gun is longer, though the increase in velocity is but very small in respect to the increase in length, the velocity being in a ratio somewhat less than that of the square roots of the length of the bore, but somewhat greater than that of the cube roots of the length, and is, indeed, nearly in the middle ratio between the two.

"4th. It appears from the ranges determined by these experiments that the range increases in a much less ratio than the velocity, and, indeed, is nearly as the square root of the velocity, the gun and elevation being the same. And when this is compared with the property of the velocity and length of gun in the foregoing paragraph, it appears that we gain extremely little in the range by a great increase in the gun, the charge being the same. And, indeed, the range is nearly as the 5th root of the length of the bore; which is so small an increase as to amount only to about 1/4th more range for a double length of gun."

The comparison of these results of experiments made at a time of vastly advanced knowledge, with the statements of Tartaglia, must, notwithstanding some of their imperfections, justify a very high estimate of the position which he would have held amongst writers on gunnery had he lived after the discoveries of Galileo and Newton.

In 1638 Galileo printed his Dialogues on Motion. In these he pointed out the general laws observed by nature in the production, resolution, and composition of motion, and was the first who described the action and effects of gravity on falling bodies. On these principles he determined that the flight of a cannon-shot, or any other projectile, would be in the curve of a parabola, except in as far as it was diverted from that track by the resistance of the air. He has also proposed the means of examining the inequalities which thence arise, and of discovering what sensible effects that resistance would produce in the motion of a bullet at a given distance from the piece.

Though Galileo had thus shown that, independently of the resistance of the air, all projectiles would, in their flight, describe the curve of a parabola; yet those who came after him seem never to have imagined that it was necessary to consider how far the operations of gunnery were affected by that resistance. The subsequent writers indeed boldly asserted, without making the experiment, that no considerable variation could arise from the resistance of the air in the flight of shells or cannon-shot. In this persuasion they supported themselves chiefly by considering the extreme rarity of the air compared with those dense and ponderous bodies; and at last it became an almost generally established maxim, that the flight of these bodies was nearly in the curve of a parabola.

In 1674, Mr Anderson, before mentioned, published his treatise on the Nature and Effects of the Gun; in which he proceeds on the principles of Galileo, and strenuously asserts that the flight of bullets is in the curve of a parabola; undertaking to answer all objections which could be brought to the contrary. The same thing was also undertaken by Mr Blondel, in a treatise published at Paris in 1683, where, after long discussion, the author concludes that the variations from the resistance of the air are so slight as scarcely to merit notice. The same subject is treated of in the Philosophical Transactions (No. 216, p. 68) by Dr Halley; and he also, swayed by the great disproportion between the density of the air and that of iron or lead, thinks it reason- able to believe that the resistance of the air to large metal shot is scarcely discernible; although in small and light shot he owns that it must be accounted for.

But though this hypothesis went on smoothly in speculation, yet Anderson, who made a great number of trials, found it impossible to support it without some new modification. For, though it does not appear that he ever examined the comparative ranges of either cannon or musket shot when fired with their usual velocities, yet his experiments on the ranges of shells thrown with small velocities, in comparison of those above mentioned, convinced him that their whole track was not parabolical. But, instead of drawing the proper inference from this, and concluding that the resistance of the air was of considerable efficacy, he framed a new hypothesis, which was, that the shell or bullet, at its first discharge, flew to a certain distance in a right line, from the end of which line only it began to describe a parabola. And this right line, which he calls the line of the impulse of the fire, he supposes to be the same in all elevations. Thus, by assigning a proper length to this line of impulse, it was always in his power to reconcile any two shots made at different angles, let them differ as widely as we may please to suppose. But this he could not have done with three shots; nor, indeed, does he ever tell us the result of his experiments when three ranges were tried at one time.

When Sir Isaac Newton's Principia was published, he particularly considered the resistance of the air to projectiles which move with small velocities; but, as he never had an opportunity of making experiments on those which move with such prodigious swiftness as shots and shells, he did not imagine that a difference in velocity could make such differences in the resistance as are now found to take place. Sir Isaac found, that in small velocities the resistance was increased in the duplicate proportion of the swiftness with which the body moved; that is, a body moving with twice the velocity of another of equal magnitude, would meet with four times as much resistance as the first; with thrice the velocity, it would meet with nine times the resistance; and so on. This principle itself is now found to be defective with regard to military projectiles; though, if it had been properly attended to, the resistance of the air might have been reckoned much more considerable than was commonly imagined. So far, however, were those who treated this subject scientifically from giving a proper allowance for the resistance of the atmosphere, that their theories differed most egregiously from the truth. Huygens alone seems to have attended to this principle. In the year 1690 he published a treatise on Gravity, in which he gave an account of some experiments tending to prove that the track of all projectiles moving with very swift motions was widely different from that of a parabola. All the rest of the learned acquiesced in the justness of Galileo's doctrine, and erroneous calculations concerning the ranges of cannon were accordingly given. Nor was any notice taken of these errors till the year 1716. At that time Ressons, a French officer of artillery, distinguished by the number of sieges at which he had served, by his high military rank, and by his abilities in his profession, presented a memoir to the Royal Academy, importing that, "although it was agreed that theory joined with practice did constitute the perfection of every art, yet experience had taught him that theory was of very little service in the use of mortars; that the works of Blondel had justly enough described the several parabolic lines, according to the different degrees of the elevation of the piece; but that practice had convinced him there was no known theory for the effect of gunpowder; for, having endeavoured, with the greatest precision, to point a mortar agreeably to these calculations, he had never been able to establish any solid foundation upon them."

From the history of the academy, it does not appear that the sentiments of Ressons were at any time controverted, or any reason offered for the failure of the theory of projectiles when applied to use. Nothing further, indeed, was done till the time of Benjamin Robins, who, in 1742, published a work entitled New Principles of Gunnery, in which he has treated particularly, not only of the resistance of the atmosphere, but of almost everything else relating to the flight of military projectiles, and, indeed, advanced the theory of gunnery much nearer perfection than it had ever before attained.

The first thing considered by Mr Robins, and which is indeed the foundation of all other particulars relative to gunnery, is the explosive force of gunpowder, which he determined to be owing to an elastic fluid similar to our atmosphere, having its elastic force greatly increased by the heat; and further, that the elasticity or pressure of the fluid produced by the firing of gunpowder is, ceteris paribus, directly as its density.

"As different kinds of gunpowder produce different quantities of this fluid in proportion to their different degrees of goodness, before any definite determination of this kind can take place, it is necessary to ascertain the particular species of powder that is proposed to be used: hence Mr Robins determined, in all his experiments, to make use of government powder, as consisting of a certain and invariable proportion of materials, and therefore preferable to such kinds as were made according to the fancy of private persons.

"This being settled, we must further premise these two principles,—1. That the elasticity of this fluid increases by heat and diminishes by cold, in the same manner as that of the air. 2. That the density of this fluid, and, consequently, its weight, is the same with the weight of an equal bulk of air, having the same elasticity and the same temperature."

By exploding powder in a receiver connected with a mercurial gauge, Robins determined that an ounce of powder produced, on explosion, nearly 576 cubic inches of gaseous fluid possessing the same elasticity as common air; and, making allowance for the increase of elasticity due to the heat of the receiver and of the red-hot iron used for igniting the powder, that the gas, when reduced to the actual temperature, would have filled 460 cubic inches. Now, to determine the ratio of the bulk of the gunpowder to the bulk of this fluid, remembering that 17 drams avoirdupois of gunpowder fill 2 inches, the proportion 16 : 17 :: 460 : 488 gave the number of cubic inches of an elastic fluid equal in density with the air produced from 2 cubic inches of powder; whence the ratio of the respective bulks of the powder and of the fluid produced from it, is nearly as 1 to 244.

"If this fluid, instead of expanding when the powder was fired, had been confined in the same space which the powder filled before the explosion, then it would have had, in that confined state, a degree of elasticity 244 times greater than that of common air; and this independent of the great augmentation which this elasticity would receive from the action of the fire at that instant.

"Hence, then, we are certain, that any quantity of powder, fired in a confined space, which it adequately fills, exerts, at the instant of its explosion, against the sides of the vessel containing it, and the bodies it impels before it, a force at least 244 times greater than the elasticity of common air, or, which is the same thing, than the pressure of the atmosphere; and this without considering the great addition which this force will receive from the violent degree of heat with which it is affected at that time."

The augmentation of the elasticity of air by temperature to the extent of "the extreme degree" of red-hot iron, Mr Robins investigated by heating to an incipient white heat a portion of a musket barrel six inches long, closed at one end and drawn out at the other conically; to an aperture of one- eight of an inch in diameter. The aperture was first closed by a wire, and the conical end of the tube after being heated was plunged into water, and the whole left to cool to the ordinary temperature of the air, when, the wire being removed, the water rushed in to fill the space now left vacant by the again contracted air. By the average of three experiments he determined the weight of the water which entered the barrel, and knowing the quantity or weight of water which would fill the whole, the difference between the two was the weight of water which would fill the portion of the barrel occupied by the cooled air. The proportion between the space occupied by the air before expanded by heat, and the same air when expanded by an incipient white heat, was determined by these experiments to be as 194\(\frac{1}{2}\) to 796.

"As air and this fluid appear to be equally affected by heat and cold, and consequently have their elasticities equally augmented by the addition of equal degrees of heat to each; if we suppose the heat with which the flame of fired powder is endowed to be the same with that of the extreme heat of red-hot iron, then the elasticity of the generated fluid will be greater at the time of the explosion than afterwards, when it is reduced to the temperature of the ambient air, in the ratio of 796 to 194\(\frac{1}{2}\) nearly. It being allowed then (which surely is very reasonable) that the flame of gunpowder is not less hot than red-hot iron, and the elasticity of the air, and consequently of the fluid generated by the explosion, being augmented in the extremity of this heat, in the ratio of 194\(\frac{1}{2}\) to 796, it follows, that if 244 be augmented in this ratio, the resulting number, which is 999\(\frac{1}{2}\), will determine how many times the elasticity of the flame of fired powder exceeds the elasticity of common air—supposing it to be confined in the same space which the powder filled before it was fired. Hence then the absolute quantity of the pressure exerted by gunpowder at the moment of its explosion may be assigned; for, since the fluid then generated has an elasticity of 999\(\frac{1}{2}\), or, in round numbers, 1000 times greater than that of the atmosphere; and since common air by its elasticity exerts a pressure on any given surface equal to the weight of the incumbent atmosphere with which it is in equilibrium, the pressure exerted by fired powder before it dilated itself is 1000 times greater than the pressure of the atmosphere; and, consequently, the quantity of this force, on a surface of an inch square, amounts to above six tons weight, which force, however, diminishes as the fluid dilates itself."

The method adopted by Robins for determining the elastic force of the gas produced by the ignition of gunpowder, when reduced to the ordinary temperature of the air, was independent of the actual nature of the gas, and therefore unaffected by the erroneous views then entertained respecting it. In fact, the weight of the gases, instead of being only three-tenths of the weight of the powder, is about six-tenths of that weight; and by the estimate of Gay Lussac, the proportion between the space occupied by the gases and by the powder would be nearly double that adopted by Robins. Gay Lussac obtained from 100 grammes of powder 50 litres of gas, and as the 100 grammes, of density 0·9, would have occupied one-ninth of a litre, the elastic force of the gas, when compressed in that space, would be \(50 \times 9 = 450\); and Captain Boxer, reasoning upon the known composition of gunpowder and the theoretical results of its decomposition as a definite chemical compound, makes it 317\(\frac{1}{2}\); but as experience has shown that these results are by no means confined to the theoretical products, it is probable that the determination of Gay Lussac is very near the truth. In like manner, the estimate of the temperature produced by the ignition of gunpowder has been variously stated, as well as the resulting elastic force; thus Gay Lussac assumes the temperature at 1000° Cent., or 1832 Fahr., and the resulting elastic pressure as 2137 atmospheres; Piobert assumed a temperature more than double that stated by Gay Lussac, and arrived at a pressure of 7500 atmospheres; but, as observed by Senderos (1862), it is impossible to determine with accuracy in this manner the impulsive force of the gases produced from the ignition of gunpowder, though, without doubt, it greatly exceeds that stated by Robins, as will be pointed out hereafter.

Having thus determined the force of the gunpowder, Mr Robins next proceeds to determine the velocity with which the ball is discharged, adopting in the solution of this problem, the two following principles, neither of which is strictly correct,—1. That the action of the powder on the bullet ceases as soon as the bullet leaves the piece. 2. That all the powder of the charge is fired and converted into elastic fluid before the bullet is sensibly removed from its place.

"The first of these," says Mr Robins, "will appear manifest when it is considered how suddenly the flame will extend itself on every side, by its own elasticity, when it is once got out of the mouth of the piece; for by this means its force will then be dissipated, and the bullet no longer sensibly affected by it.

"The second principle is indeed less obvious, being contrary to the general opinion of almost all writers on this subject. It might, however, be sufficient for the proof of this position, to observe the prodigious compression of the flame in the chamber of the piece. Those who attend to this circumstance, and to the easy passage of the flame through the intervals of the grains, may soon satisfy themselves that no one grain contained in that chamber can continue for any time unimflamed, when thus surrounded and pressed by such an active fire. However, not to rely on mere speculation in a matter of so much consequence, I considered that if part only of the powder is fired, and that successively; then, by laying a greater weight before the charge (suppose two or three bullets instead of one), a greater quantity of powder would necessarily be fired, since a heavier weight would be a longer time in passing through the barrel. Whence it should follow that two or three bullets would be impelled by a much greater force than one only. But the contrary to this appears by experiment; for, firing one, two, and three bullets laid contiguous to each other with the same charge respectively, I have found that their velocities were not much different from the reciprocal of their subduplicate quantities of matter; that is, if a given charge would communicate to one bullet a velocity of 1700 feet in a second, the same charge would communicate to two bullets a velocity of from 1250 to 1300 feet in a second, and to three bullets a velocity of from 1050 to 1110 feet in the same time. From hence it appears, that whether a piece is loaded with a greater or less weight of bullet, the action is nearly the same. The excess of the velocities of the two and three bullets above what they ought to have been by this rule (which are that of 1200 and 980 feet in a second), undoubtedly arises from the flame, which, escaping by the side of the first bullet, acts on the surface of the second and third. Now this excess has in many experiments been imperceptible, and the velocities have been reciprocally in the subduplicate ratios of the number of bullets, to sufficient exactness; and where this error has been greater, it has never arisen to an eighth part of the whole; but if the common opinion was true, that a small part only of the powder fires at first, and other parts of it successively as the bullet passes through the barrel, and that a considerable part of it is often blown out of the piece without firing at all, then the velocity which three bullets received from the explosion ought to have been much greater than we have found it to be."

"With respect to the grains of powder which are often blown out unfired, and which are always urged as a proof of the gradual firing of the charge, there may perhaps be some few grains in the best powder of such an heteroge- neous composition as to be less susceptible of firing; which, I think, I have myself observed; and these, though they are surrounded by the flame, may be driven out unfired."

Such were the reasonings of Mr Robins; but however rapid the ignition of gunpowder, it is still progressive; and without doubt the ball moves before the whole impulse of the powder from its complete ignition has been received, and it is equally certain that some portion, however small, of the powder is generally thrown out unburnt. Were it not indeed for the movement of the ball before the full development of the elastic force of the gases, accidents from the bursting of guns would be frequent, as may be judged from the consequence of any impediment in the way of the movement of the ball, or from accidentally leaving it at a distance from the charge. Senderos observes—"The full force of gunpowder, with the intensity it possesses, is not used in fire-arms, but only a small part of it. It is undoubtedly that the transmission of any force requires time. The projectile opposes a resistance proportioned to its mass or inertia, and as soon as the force has become sufficient to overcome that resistance, the projectile begins to move, and allows the gases to expand into a larger space, thus losing density and caloric before they exert their full force on the gun."

"These postulates being allowed to be just, let AB, fig. 6, represent the axis of any piece of artillery; A the breech, and B the muzzle; DC the diameter of its bore, and DEGC a part of its cavity filled with powder. Suppose the ball that is to be impelled to lie with its hinder surface at the line GE; then the pressure exerted at the explosion on the circle of which GE is the diameter, or, which is the same thing, the pressure exerted in the direction FB on the surface of the ball is easily known from the known dimensions of that circle. Draw any line FH perpendicular to FB, and AI parallel to FH; and through the point H to the asymptotes IA and AB, describe the hyperbola KHNQ; then, if FH represents the force impelling the ball at the point F, the force impelling the ball at any other point, as at M, will be represented by the line MN, the ordinate to the hyperbola at that point. For when the fluid impelling the body along has dilated itself to M, its density will be then to its original density in the space DEGC reciprocally as the spaces through which it is extended—that is, as FA to MA, or as MN to FH; but it has been shown that the impelling force or elasticity of this fluid is directly as its density, therefore, if FH represents the force at the point F, MN will represent the like force at the point M.

"Since the absolute quantity of the force impelling the ball at the point F is known, and the weight of the ball is also known, the proportion between the force with which the ball is impelled and its own gravity is known. In this proportion take FH to FL, and draw LP parallel to FB; then, MN the ordinate to the hyperbola in any point will be to its part MR, cut off by the line LP, as the impelling force of the powder in that point M to the gravity of the ball; and consequently the line LP will determine a line proportional to the uniform force of gravity in every point; whilst the hyperbola HNQ determines in like manner such ordinates as are proportional to the impelling force of the powder in every point; whence, by the 39th Prop. of lib. i. of Sir Isaac Newton's Principia, the areas FLPB and FHQB are in the duplicate proportion of the velocities which the ball would acquire when acted upon by its own gravity through the space FB, and when impelled through the same space by the force of the powder. But since the ratio of AF to AB and the ratio of FH to FL are known, the ratio of the area FLPB to the area FHQB is known; and thence its subduplicate. And since the line FB is given in magnitude, the velocity which a heavy body would acquire when impelled through this line by its own gravity is known; being no other than the velocity it would acquire by falling through a space equal to that line: find then another velocity to which this last-mentioned velocity bears the given ratio of the subduplicate of the area FLPB to the area FHQB; and this velocity thus found is the velocity the ball will acquire when impelled through the space FB by the action of the inflamed powder.

"Now, to give an example of this: Let us suppose AB, the length of the cylinder, to be 45 inches; its diameter DC, or rather the diameter of the ball, to be \( \frac{2}{3} \)ths of an inch; and AF, the extent of the powder, to be 24ths inches; to determine the velocity which will be communicated to a leaden bullet by the explosion, supposing the bullet to be laid at first with its surface contiguous to the powder.

"By the theory we have laid down, it appears, that at the first instant of the explosion the flame will exert, on the bullet lying close to it, a force 1000 times greater than the pressure of the atmosphere. The medium pressure of the atmosphere is reckoned equal to a column of water 33 feet in height; whence, lead being to water as 11:345 to 1, this pressure will be equal to that of a column of lead 3:49 inches in height. Multiplying this by 1000, therefore, a column of lead 34,900 inches (upwards of half a mile) in height, would produce a pressure on the bullet equal to what is exerted by the powder in the first instant of the explosion; and the leaden ball being \( \frac{2}{3} \)ths of an inch in diameter, and consequently equal to a cylinder of lead of the same base half an inch in height, the pressure at first acting on it will be equal to 34,900 x 2, or 69,800 times its weight; whence FL to FH is as 1 to 69,800; and FB to FA as 45 - 23, or \( \frac{42}{2} \) to \( \frac{2}{2} \), that is, as 339 to 21; whence the rectangle FLPB is to the rectangle AFHS as 339 to 21 x 69,800, that is, as 1 to 4324. And from the known application of the logarithms to the mensuration of the hyperbolic spaces, it follows that the rectangle AFHS is to the area FHQB as 43429, &c., is to the tabular logarithm of \( \frac{AF}{AB} \); that is, of \( \frac{AF}{AB} \), which is 1:2340579: whence the ratio of the rectangle FLPB to the hyperbolic area FHQB is compounded of the ratios of 1 to 4324—and of 43429, &c., to 1:2340579; which together make up the ratio of 1 to 12263, the subduplicate of which is the ratio of 1 to 110:7; and in this ratio is the velocity which the bullet would acquire by gravity in falling through a space equal to FB, to the velocity the bullet will acquire from the action of the powder impelling it through FB. But the space FB being 42\( \frac{2}{3} \) inches, the velocity a heavy body will acquire in falling through such a space is known to be what would carry it nearly at the rate of 15:07 feet in a second; whence the velocity to which this has the ratio of 1 to 110:7 is a velocity which would carry the ball at the rate of 1668 feet in one second. And this is the velocity which, according to the theory, the bullet in the present circumstances would acquire from the action of the powder during the time of its dilatation.

"Now this velocity being once computed for one case, is easily applied to any other; for if the cavity DEGC left behind the bullet be only in part filled with powder, then the line HF, and consequently the area FHQB, will be diminished in the proportion of the whole cavity to the part filled. If the diameter of the bore be varied, the lengths AB and AF remaining the same, then the quantity of powder and the surface of the bullet which it acts on will be varied in the duplicate proportion of the diameter, but the weight of the bullet will vary in the triplicate proportion of Gunnery, the diameter; wherefore the line FH, which is directly as the absolute impelling force of the powder, and reciprocally as the gravity of the bullet, will change in the reciprocal proportion of the diameter of the bullet. If AF, the height of the cavity left behind the bullet, be increased or diminished, the rectangle of the hyperbola, and consequently the area corresponding to ordinates in any given ratio, will be increased or diminished in the same proportion. From all which it follows, that the area FHQB, which is in the duplicate proportion of the velocity of the impelled body, will be directly as the logarithm $\frac{AB}{AF}$ (where AB represents the length of the barrel, and AF the length of the cavity left behind the bullet); also directly as the part of that cavity filled with powder, and inversely as the diameter of the bore, or rather of the bullet; likewise directly as AF, the height of the cavity left behind the bullet. Consequently the velocity being computed as above, for a bullet of a determined diameter, placed in a piece of a given length, and impelled by a given quantity of powder, occupying a given cavity behind that bullet; it follows, that by means of these ratios, the velocity of any other bullet may be thence deduced; the necessary circumstances of its position, quantity of powder, &c., being given. Where note, that in the instance of this supposition, we have supposed the diameter of the hall to be 4ths of an inch; whence the diameter of the bore will be something more, and the quantity of powder contained in the space DEGC will amount exactly to twelve pennyweights, a small wad of tow included.

"In order to compare the velocities communicated to bullets by the explosion, with the velocities resulting from the theory by computation, it is necessary that the actual velocities with which bullets move should be discovered. The only methods hitherto practised for this purpose, have been either by observing the time of the flight of a shot through a given space, or by measuring the range of a shot at a given elevation; and thence computing, on the parabolic hypothesis, what degree of velocity would produce this range. The first method labours under this insurmountable difficulty, that the velocities of these bodies are often so swift, and consequently the time observed is so short, that an imperceptible error in that time may occasion an error in the velocity thus found of 200, 300, 400, 500, or 600 feet, in a second. The other method is so fallacious, by reason of the resistance of the atmosphere (to which inequality the first is also liable), that the velocities thus assigned may not perhaps be the tenth part of the actual velocities sought.

"The simplest method of determining this velocity is by means of the instrument (the Ballistic Pendulum), represented in fig. 7, where ABCD represents the body of the machine composed of the three poles B, C, D, spreading at bottom, and joining together at the top A; being the same with what is vulgarly used in lifting and weighing very heavy bodies, and is called by workmen the triangles. On two of these poles, towards their tops, are screwed on the sockets R, S; and on these sockets the pendulum EFGHIK is hung by means of its cross-piece EF, which becomes its axis of suspension, and on which it must be made to vibrate with great freedom. The body of this pendulum is made of iron, having a broad part at bottom, and its lower part is covered with a thick piece of wood GKIH, which is fastened to the iron by screws. Something lower than the bottom of the pendulum there is a brace OP, joining the two poles from which the pendulum is suspended; and to this brace there is fastened a contrivance MNU, made with two edges of steel, bearing on each other in the line UN, something in the manner of a drawing-pen; the strength with which these edges press on each other being diminished or increased at pleasure by means of a screw Z going through the upper piece. There is fastened to the bottom of the pendulum a narrow ribbon LN, which passes between these steel edges, and which afterwards, by means of an opening cut in the lower piece of steel, hangs loosely down, as at W.

"With this apparatus, if the weight of the pendulum be known, and likewise the respective distances of its centre of gravity and of its centre of oscillation from its axis of suspension, it will thence be known what motion will be communicated to this pendulum by the percussion of a body of a known weight moving with a known degree of celerity, and striking it in a given point; that is, if the pendulum be supposed at rest before the percussion, it will be known what vibration it ought to make in consequence of such a determined blow; and, on the contrary, if the pendulum, being at rest, is struck by a body of a known weight, and the vibration which the pendulum makes after the blow is known, the velocity of the striking body may from thence be determined. Hence, then, if a bullet of a known weight strikes the pendulum, and the vibration which the pendulum makes in consequence of the stroke be ascertained, the velocity with which the ball moved is thence to be known.

"Now the extent of the vibration made by the pendulum after the blow, may be measured to great accuracy by the ribbon LN. For let the pressure of the edges UN on the ribbon be so regulated by the screw Z, that the motion of the ribbon between them may be free and easy, though with some minute resistance; then, settling the pendulum at rest, let the part LN between the pendulum and the edges be drawn strait, but not strained, and fix a pin in that part of the ribbon which is then contiguous to the edges; let now a ball impinge on the pendulum; then the pendulum swinging back will draw out the ribbon to the just extent of its vibration, which will consequently be determined by the interval on the ribbon between the edges UN and the place of the pin.

"The weight of the whole pendulum, wood and all, was 56 pounds 3 ounces; its centre of gravity was 52 inches distant from its axis of suspension, and 200 of its small swings were performed in the time of 253 seconds; whence its centre of oscillation is 62\(\frac{1}{4}\) inches distant from that axis. The centre of the piece of wood GKIH is distant from the same axis 66 inches. In the compound ratio of 66 to 62\(\frac{1}{4}\), and 66 to 52, take the quantity of matter of the pendulum to a fourth quantity, which will be 42 lbs. \(\frac{1}{2}\) oz. Now geometers well know, that if the blow be struck on the centre of the piece of wood GKIH, the pendulum will resist to the stroke in the same manner as if this last quantity of matter only (42 lbs. \(\frac{1}{2}\) oz.) was concentrated in that point, and the rest of the pendulum was taken away; whence, supposing the weight of the bullet impinging in that point to be the \(\frac{1}{8}\)th of a pound, or the \(\frac{1}{8}\)\(\frac{1}{2}\)th of this quantity of matter nearly, the velocity of the point of oscillation after the stroke will, by the laws observed in the congress of such bodies as rebound not from each other, be the \(\frac{1}{8}\)\(\frac{1}{2}\)th of the velocity the bullet moved with before the stroke; whence the velocity of this point of oscillation after the stroke being ascertained, that multiplied by 505 will give the velocity with which the ball impinged.

"But the velocity of the point of oscillation after the stroke is easily deduced from the chord of the arch through which it ascends by the blow; for it is a well-known proposition, that all pendulous bodies ascend to the same height by their vibratory motion as they would do if they were projected directly upwards from their lowest point, with the Gunnery.

same velocity they have in that point; wherefore, if the versed sine of the ascending arch be found (which is easily determined from the chord and radius being given), this versed sine is the perpendicular height to which a body projected upwards with the velocity of the point of oscillation would arise; and consequently what that velocity is, can be easily computed by the common theory of falling bodies.

"For instance, the chord of the arch, described by the ascent of the pendulum after the stroke measured on the ribbon, has been sometimes $17\frac{1}{4}$ inches; the distance of the ribbon from the axis of suspension is $71\frac{1}{4}$ inches; whence reducing $17\frac{1}{4}$th in the ratio of $71\frac{1}{4}$th to 66, the resulting number, which is nearly 16 inches, will be the chord of the arch through which the centre of the board GKH ascended after the stroke; now the versed sine of the arch, whose chord is 16 inches, and its radius 66, is $193989$; and the velocity which would carry a body to this height, or, which is the same thing, the velocity which a body would acquire by descending through this space, is nearly that of $3\frac{1}{4}$ feet in $1^{\circ}$.

"To determine then the velocity with which the bullet impinged on the centre of the wood, when the chord of the arch described by the ascent of the pendulum, in consequence of the blow, was $17\frac{1}{4}$ inches measured on the ribbon, no more is necessary than to multiply $3\frac{1}{4}$th by 505, and the resulting number, 1641, will be the feet which the bullet would describe in $1^{\circ}$; if it moved with the velocity it had at the moment of its percussion; for the velocity of the point of the pendulum on which the bullet struck, we have just now determined to be that of $3\frac{1}{4}$ feet in $1^{\circ}$; and we have before shown that this is the $\frac{2}{5}$th of the velocity of the bullet. If then a bullet weighing $\frac{2}{5}$th of a pound strikes the pendulum in the centre of the wood GKH, and the ribbon be drawn out $17\frac{1}{4}$ inches by the blow, the velocity of the bullet is that of $1641$ feet in $1^{\circ}$. And since the length the ribbon is drawn is always nearly the chord of the arch described by the ascent (it being placed so as to differ insensibly from those chords which most frequently occur), and these chords are known to be in the proportion of the velocities of the pendulum acquired from the stroke; it follows that the proportion between the lengths of ribbon drawn out at different times will be the same with that of the velocities of the impinging bullets; and consequently, by the proportion of these lengths of ribbon to $17\frac{1}{4}$th, the proportion of the velocity with which the bullets impinge, to the known velocity of $1641$ feet in $1^{\circ}$, will be determined. Hence then is shown in general how the velocities of bullets of all kinds may be found out by means of this instrument."

Mr Robins then gave several precautionary rules for securing precision in the experiments, and guarding against accidents, amongst which were the two following:

"The weight of the pendulum and the thickness of the wood necessary to prevent the bullets from being shivered by striking directly on the iron, must be in some measure proportioned to the size of the bullets which are used. A pendulum of the weight here described will do very well for all bullets under three or four ounces, if the thickness of the board be increased to seven or eight inches for the heaviest bullets. Beech is the toughest and properest wood for this purpose.

"The powder used in these experiments should be exactly weighed; and that no part of it be scattered in the barrel, the piece must be charged with a ladle, in the same manner as is practised with cannon; the wad should be of tow, of the same weight each time, and no more than is just necessary to confine the powder in its proper place; the length of the cavity left behind the ball should be determined each time with exactness; for the increasing or diminishing that space will vary the velocity of the shot, although the bullet and quantity of powder be not changed.

The distance of the mouth of the piece from the pendulum ought to be such, that the impulse of the flame may not act on the pendulum; this will be prevented in a common barrel charged with half an ounce of powder, if it be at the distance of 16 or 18 feet: in larger charges the impulse is sensible farther off; I have found it to extend to above 25 feet; however, between 25 and 18 feet is the distance I have usually chosen."

With this instrument, or others similar to it, Mr Robins made a great number of experiments on barrels of different lengths, and with different charges of powder. He has given us the results of sixty-one of these; and having compared the actual velocities with the computed ones, his theory appears to have come as near the truth as could well be expected. In seven of the experiments there was a perfect coincidence; the charges of powder being 6 to 12 pennyweights, the barrels 45, 24-312 and 7-06 inches in length. The diameter of the first (marked A) was $\frac{3}{8}$ths of an inch; of the second (B) was the same; and of D, '83 of an inch. In the first of these experiments, another barrel (C) was used, whose length was 12-375 inches, and the diameter of its bore $\frac{3}{8}$ inch. In fourteen more of the experiments, the difference between the length of the chord of the pendulum's arch shown by the theory and the actual experiment, was $\frac{3}{8}$ths of an inch over or under. This showed an error in the theory, varying, according to the different lengths of the chord, from $\frac{3}{8}$th to $\frac{3}{8}$th of the whole; the charges of powder were the same as in the last. In sixteen other experiments the error was $\frac{3}{8}$ths of an inch, varying from $\frac{3}{8}$th to $\frac{3}{8}$th of the whole; the charges of powder were 6, 8, 9, or 12 pennyweights. In seven other experiments the error was $\frac{3}{8}$ths of an inch, varying from $\frac{3}{8}$th to $\frac{3}{8}$th of the whole; the charges of powder 6 or 12 pennyweights. In eight experiments the difference was $\frac{3}{8}$ths of an inch, indicating an error of from $\frac{3}{8}$th to $\frac{3}{8}$th of the whole; the charges being 6, 9, 12, and 24 pennyweights of powder. In three experiments the error was $\frac{3}{8}$ths, varying from $\frac{3}{8}$th to $\frac{3}{8}$th of the whole; the charges 8 and 12 pennyweights of powder. In two experiments the error was $\frac{3}{8}$ths, in one case amounting to something less than $\frac{3}{8}$d, in the other to $\frac{3}{8}$d of the whole; the charges 12 and 36 pennyweights of powder. By one experiment the error was $\frac{3}{8}$ths, and by another $\frac{3}{8}$ths; the first amounting to $\frac{3}{8}$th nearly, the latter to almost $\frac{3}{8}$th of the whole; the charges of powder 6 or 12 pennyweights. The last error, however, Mr Robins ascribes to the wind. The two remaining experiments varied from theory by 1-3 inches, somewhat more than $\frac{3}{8}$th of the whole; the charges of powder were 12 pennyweights in each; and Mr Robins ascribes the error to the dampness of the powder. In another case he ascribes an error of $\frac{3}{8}$ths to the blast of the powder on the pendulum.

From these experiments Mr Robins deduces the following conclusions:—"The variety of these experiments, and the accuracy with which they correspond to the theory, leave us no room to doubt of its certainty. This theory, as here established, supposes that, in the firing of gunpowder, about $\frac{3}{8}$ths of its substance is converted by the sudden inflammation into a permanently elastic fluid, whose elasticity, in proportion to its heat and density, is the same with that of common air in the like circumstances: it farther supposes that all the force exerted by gunpowder in its most violent operations is no more than the action of the elasticity of the fluid thus generated; and these principles enable us to determine the velocities of bullets impelled from fire-arms of all kinds, and are fully sufficient for all purposes where the force of gunpowder is to be estimated.

"From this theory many deductions may be made of the greatest consequence to the practical part of gunnery." Gunnery. From hence the thickness of a piece, which will enable it to confine, without bursting, any given charge of powder, is easily determined, since the effort of the powder is known; and from it we are taught the necessity of leaving the same space behind the bullet, when we would, by the same quantity of powder, communicate to it an equal degree of velocity; since, on the principles already laid down, it follows that the same powder has a greater or less degree of elasticity, according to the different spaces it occupies. The method which I have always practised for this purpose has been by marking the rammer; and this is a maxim which ought not to be dispensed with when cannon are fired at an elevation, particularly in those called by the French batteries & ricochet.

"From the continued action of the powder, and its manner of expanding described in this theory, and the length and weight of the pieces, one of the most essential circumstances in the well-directing of artillery may be easily ascertained. All practitioners are agreed that no shot can be depended on, unless the piece be placed on a solid platform; for if the platform shakes with the first impulse of the powder, it is impossible but the piece must also shake, which will alter its direction, and render the shot uncertain. To prevent this accident, the platform is usually made extremely firm to a considerable depth backwards; so that the piece is not only well supported in the beginning of its motion, but likewise through a great part of its recoil. However, it is sufficiently obvious that when the bullet is separated from the piece, it can be no longer affected by the trembling of the piece or platform; and, by a very easy computation, it will be found that the bullet will be out of the piece before the latter hath recoiled half an inch.

"If the whole substance of the powder was converted into an elastic fluid at the instant of the explosion, then, from the known elasticity of this fluid assigned by our theory, and its known density, we could easily determine the velocity with which it would begin to expand, and could thence trace out its future augmentations in its progress through the barrel; but as we have shown that the elastic fluid, in which the activity of the gunpowder consists, is only 3/5ths of the substance of the powder, the remaining 2/5ths will, in the explosion, be mixed with the elastic part, and will, by its weight, retard the activity of the explosion; and yet they will not be so completely united as to move with one common motion; but the unelastic part will be less accelerated than the rest, and some will not even be carried out of the barrel, as appears by the considerable quantity of unctuous matter which adheres to the inside of all fire-arms after they have been used."

Mr Robins then investigates the cause of these irregularities in the expansive motion of the fluid by experiments; but before referring to them, it is right to observe, as has been before stated, that in British gunpowder, consisting of 75 parts of nitre, 15 of charcoal, and 10 of sulphur, the potassium of the nitre and the sulphur are the only constituents which unite to form a solid residuum, the sulphate of potassium, and that their weight being about 39 lbs. per cent., the remaining 61 lbs., or 4/5ths of the whole, form gaseous elastic products.

"The experiments made use of for this purpose were of two kinds. The first was made by charging a barrel A with 12 pennyweights of powder, and a small wad of tow only; and then placing its mouth 19 inches from the centre of the pendulum. On firing it in this situation, the impulse of the flame made it ascend through an arch whose chord was 13.7 inches; whereas, if the whole substance of the powder was supposed to strike against the pendulum, and each part to strike with the same velocity, that common velocity must have been at the rate of about 2650 feet in a second. But, as some part of the velocity of the flame was lost in passing through 19 inches of air, I made the remaining experiments in a manner not liable to this inconvenience.

"I fixed the barrel A on the pendulum, so that its axis might be both horizontal and also perpendicular to the plane HK; or, which is the same thing, that it might be in the plane of the pendulum's vibration; the height of the axis of the piece above the centre of the pendulum was 6 inches, and the weight of the piece, and of the iron that fastened it, &c., was 12½ lbs. The barrel in this situation being charged with 12 pennyweights of powder, without either ball or wad, only put together with the rammer; on the discharge the pendulum ascended through an arch whose chord was 10 inches, or, reduced to an equivalent blow in the centre of the pendulum, supposing the barrel away, it would be 14.4 inches nearly. The same experiment being repeated, the chord of the ascending arch was 10½ inches, which, reduced to the centre, is 14.6 inches.

"To determine what difference of velocity there was in the different parts of the vapour, I loaded the piece again with 12 pennyweights of powder, and rammmed it down with a wad of tow weighing 1 pennyweight. Now, I conceived that this wad, being very light, would presently acquire that velocity with which the elastic part of the fluid would expand itself when uncompressed; and I accordingly found that the chord of the ascending arch was by this means increased to 12 inches, or at the centre to 17.3; whence, as the medium of the other two experiments is 14.5, the pendulum ascended through an arch 2.8 inches longer, by the additional motion of 1 pennyweight of matter, moving with the velocity of the swiftest part of the vapour; and, consequently, the velocity with which this pennyweight of matter moved was that of about 7000 feet in a second."

Mr Robins here adduces some experiments to obviate a possible objection by showing that the confinement of the powder was not necessary to ensure its total ignition and the full development of its elastic force, and "that the push of the recoil, arising from the expansion of the powder alone, is found to be no greater when it impels a leaden bullet beyond it than when the same quantity is forced without any wad to confine it;" and then proceeds as follows:

"Again, that this velocity of 7000 feet in a second is not much beyond what the most active part of the flame acquires in expanding, is evinced from hence, that in some experiments a ball has been found to be discharged with a velocity of 2400 feet in a second, and yet it appeared not that the action of the powder was at all diminished on account of this immense velocity; consequently, the degree of swiftness with which, in this instance, the powder followed the ball without losing any part of its pressure, must have been much short of what the powder alone would have expanded with had the ball not been there.

"From these determinations may be deduced the force of petards, since their action depends entirely on the impulse of the flame; and it appears that a quantity of powder properly disposed in such a machine may produce as violent an effect as a bullet of twice its weight, moving with a velocity of 1400 or 1500 feet in a second."

However ingenious the researches of Mr Robins into this important element of gunnery—the velocity with which the gases produced by the ignition of gunpowder expand—they have not been admitted by some as satisfactorily solving the question; and yet Hutton, although, by a combination of experiment and calculation, he had deduced a velocity varying from 3000 to 5000 feet, after correcting one of the quantities in his formula, at first assumed too high, arrived at a conclusion very nearly the same as the experimental one of Robins. The determination, indeed, of the velocity of the elastic gases is attended with much difficulty, as is that (as before pointed out) of the initial force with which these gases act upon the projectile they are intended to propel. Robins considered this force to be about 1000 atmospheres; but Hutton found it to vary, according to the charge and the length of gun, from 1700 to 2300, and he therefore considers it as fairly represented by about 2000 atmospheres, and his results were confirmed by those of Dr Gregory, who made it 2250. Now, Hutton's formula for determining the ultimate velocity of the ball, and conse- Gunnery.

Gunnery. frequently of the gas then pressing against and urging it forward, is

\[ V = \frac{467}{p + w} \times \log_b \left( \frac{nhd^2}{a} \right) \]

where \( a \) represents the height or length of the charge, including cartridge, or of the space behind the ball, \( b \) the whole length of the gun-bore, \( d \) the length of the portion of the cylinder or bore which would be filled with the powder, \( d \) the diameter of the ball or of the bore, \( n \) the ratio of the first force of the fired powder to the pressure of the atmosphere as 1, \( w \) the weight of the ball, and \( p \) a quantity having some fixed relation to the weight of the charge; and if in this formula the weight of the ball be made 0, \( V \) becomes the value of the velocity of the expanding gas.

But here enters a difficulty, as it is not easy to determine what proportion of the weight of the powder ought to be assumed for \( p \), from the uncertainty of the actual condition of the gases and of the solid residuum, at the moment of decomposition of the powder. Supposing an equal density to exist throughout the bulk of the gases, and that the solid residuum is diffused equally through them, \( p \) should be, as Hutton at first assumed it, \( \frac{1}{2} \) of the weight of the powder; but, as it is more probable that the rear portion of the gas is much more condensed than the front portion, and consequently, that the centre of gravity of the whole gas has moved through a still less space, \( p \) must be taken less than \( \frac{1}{2} \), and in this manner Hutton found that the velocity of the gases, when \( p \) was taken as \( \frac{1}{3} \) of the weight of the powder, became between 7000 and 8000 feet per second; and when taken \( \frac{1}{4} \), from 3000 to 5000—results sufficient in themselves to prove how impossible almost it must be to determine theoretically the velocity of the gases. In investigating the decomposition of gunpowder, there are two points to be taken into consideration—the velocity of ignition, and the velocity of combustion; or, in other words, the time required to burn each grain of powder, on the one hand, and the time necessary for communicating ignition, as the flame is conveyed by the expanding gases with great rapidity from one grain to another. Piohert has endeavoured to estimate the velocity of combustion independently of that of ignition by forming a kind of bar with a paste of powder, 1 foot 2 inches in length, and about \( \frac{1}{2} \) of an inch square, the bar being smeared with fine hog's lard, and placed vertically on a plate with water. This bar, weighing 380 grammes, was ignited at the top, and required 29-2 seconds for combustion, being at the rate of \( \frac{1}{486} \) of an inch per second.

By other experiments of the same author, powder inclosed and slightly compressed in a tube \( \frac{1}{2} \) of an inch in diameter and open at one end, burnt at the rate of \( \frac{3}{4} \) of an inch per second, or, when strongly compressed, at the rate of \( \frac{4}{6} \) of an inch per second. From these statements it is evident that, however rapid the combustion of powder, it is not instantaneous; and that the great object is to facilitate the transmission of the flame through the powder so as to render the ignition of the whole as nearly simultaneous as possible. The process of granulating powder for this purpose was early introduced, as Luis Collado, before mentioned, expressly points out the greater force of powder when grained as compared to that of its meal; and Cyprian Lucar explains the mode of graining or "corning" the powder by passing it through sieves after having broken up the cake which had been first formed in the incorporating process. The size of the grain is an important element, and ought to be so arranged as to reduce the time of combustion to the minimum consistent with a due rapidity of ignition; and more particularly so as the denser the powder the greater quantity of gas must be produced at the same space, and the greater therefore the elastic force developed; whilst, as regards the grain itself, anything which increases its density must increase the velocity of ignition and diminish that of combustion, whilst the rapidity of combustion increases as the grains are more porous and less smooth.

These observations sufficiently demonstrate that the combustion of the charge cannot be effected in less time than that required for the combustion of a grain; but in this respect it must be remembered that the combustion proceeds from the circumference to the centre, and therefore requires only half the time as compared with Piohert's experiments. If, then, each grain were \( \frac{1}{4} \) of an inch in diameter, the complete combustion would be effected in \( \frac{1}{4} \) of a second; and if \( \frac{1}{2} \) th, in \( \frac{1}{2} \) th of a second; but long before that time the quantity of gas evolved must have been sufficient to move the ball, its ultimate velocity depending on the time it remains in the bore, or, in other words, on the more complete combustion of the powder, as well as on the continuance of the action of the gases produced.

"In many of the experiments already recited the ball was not laid immediately contiguous to the powder, but at a small distance, amounting, at the utmost, only to \( \frac{1}{4} \) inch. In these cases the theory agreed very well with the experiments. But if a bullet is placed at a greater distance from the powder—suppose at 12, 18, or 24 inches—we cannot then apply to this ball the same principles which may be applied to those laid in contact, or nearly so, with the powder; for, when the surface of the fired powder is not confined by a heavy body, the flame dilates itself with a velocity far exceeding that which it can communicate to a bullet by its continued pressure; consequently, as, at the distance of 12, 18, or 24 inches, the powder will have acquired a considerable degree of this velocity of expansion, the first motion of the ball will not be produced by the continued pressure of the powder, but by the actual percussion of the flame; and it will therefore begin to move with a quantity of motion proportioned to the quantity of this flame, and the velocities of its respective parts.

"From hence, then, it follows, that the velocity of the bullet, laid at a considerable distance before the charge, ought to be greater than what would be communicated to it by the pressure of the powder acting in the manner already mentioned; and this deduction from our theory we have confirmed by manifold experience, by which we have found that a ball laid in the barrel A, with its hinder part \( \frac{1}{4} \) inches from its breech, and impelled by 12 pennyweights of powder, has acquired a velocity of about 1400 feet in a second; when, if it had been acted on by the pressure of the flame only, it would not have acquired a velocity of 1200 feet in a second. The same we have found to hold true in all other greater distances (and also in lesser, though not in the same degree), and in all quantities of powder; and we have likewise found, that these effects nearly correspond with what has been already laid down about the velocity of expansion and the elastic and unelastic parts of the flame.

"From hence, too, arises another consideration of great consequence in the practice of gunnery; which is, that no bullet should at any time be placed at a considerable distance from the charge, unless the piece is extremely well fortified; for a moderate charge of powder, when it has expanded itself through the vacant space, and reaches the ball, will, by the velocity each part has acquired, accumulate itself behind the ball, and thereby be condensed prodigiously; whence, if the barrel be not extremely firm in that part, it must, by means of this reinforced elasticity, infallibly burst. The truth of this reasoning I have experimented in an exceeding good Tower matchet, forged of very tough iron; for, charging it with 12 pennyweights of powder, and placing the ball 16 inches from the breech, on firing it the part of the barrel just behind the bullet was swelled out to double its diameter, like a blown bladder, and two large pieces of 2 inches long were burst out of it.

"Having seen that the entire motion of a bullet laid at a considerable distance from the charge is acquired by two different methods in which the powder acts on it, the first being the percussion of the parts of the flame with the velocity they had respectively acquired by expanding, the second the continued pressure of the flame through the remaining part of the barrel, I endeavoured to separate these different actions, and to retain that only which arose from the continued pressure of the flame. For this purpose I no longer placed the powder at the breech, from whence it would have full scope for its ex-