half round on its bar, correct it, if wrong, in the same manner as you did the vertical hair.
N.B. Of the four small screws at the eye-end of the telescope, those at the right and left hand move whatever hair is vertical, and those at top or underneath move whatever hair is horizontal.
On the side of the gun upon the first reinforce, are cast two knobs, F, fig. 9, and 14, having their middle part distant from each other six inches, for fixing on the brass-cocks, A, fig. 14, and 15, which receive the rectangular ends of the parallel cylindric bar of the sector, when placed on the gun.
The next adjustment is to make the parallel bar, and line of collimation of the telescope, when set at 0 degrees, parallel to the bore of the gun, and consequently to the direction of the shot. The gun being loaded, the cartridge pricked, and the gun primed, place the sector on the cocks of the gun; and having first set the sector to what elevation you judge necessary, bring the intersection of the cross hairs in the telescope upon the centre of the mark, the limb of the sector being set vertical by means of the circular level, and then take off the sector without moving the gun. Fire the gun; and if the bullet hits anywhere in the perpendicular line, passing through the centre of the mark, the line of collimation of the telescope and direction of the shot agree; but if it hit to the right of the mark, so much do they differ. In order to correct which, bring the gun into the same position it was in before firing, and secure it there. Then file away as much of the fore cock, on the side next the gun, as will let the intersection of the cross-hair fall somewhere on the line passing perpendicularly through the point where the shot fell; and it is then adjusted in that position, so much being filed off the side of the cock at o, fig. 14, and 15, as will allow the side b to be screwed closer, that the ends of the parallel bar may have no shake in the cocks. To correct it in the other position, and so to find the true 0 degrees of the gun, that is, to bring the line of collimation of the telescope, parallel bar, and bore of the gun, truly parallel to each other, repeat the above with the trunnions perpendicular to the horizon, the sector being turned a quarter round upon its bar, so as to bring its plane vertical. The deviation of the shot found in this way is corrected by deepening one of the cocks, so that the vertical hair of the telescope may be brought to cover the line passing perpendicularly through the point where the bullet hits; the gun being placed in the same position it was in before it was fired. This adjustment being repeated two or three times, and any error that remains being corrected, the gun is fit to be mounted on its carriage for service. It is to be observed, that this sector will fit any gun, if the cocks and rectangular ends, &c. of the parallel bar be of the above dimensions, and will be equally applicable to all such pieces whose cocks have been adjusted, as if it had been adjusted separately with each of them. And if the sector be set at any degree of elevation, and the gun moved so as to bring the intersection of the cross-hairs on the object to be fired at (the limb of the sector being vertical), the bore of the gun will have the same elevation above it, in the true direction of the shot, whatever position the carriage of the gun is standing in. A telescope with cross hairs, fixed to a common rifled musket, and adjusted to the direction of the shot, will make any person, with a very little practice, hit an object with more precision than the most experienced marksman.
For garrison service, or for batteries, the ship or Their carriage, with two iron staples on each side to put through a couple of poles to carry these guns from place to place with more dispatch, are as proper as any. But, for the field, a carriage like that at fig. 16, where Fig. 16, the shafts push in upon taking out the iron pins a b, and moving the cross bar A, upon which the breech of the gun rests, as far down as the shafts were pushed in, is the properest, since the whole can then be carried like a hand-barrow, over ditches, walls, or rough ground, all which may be easily understood from the figure.
The principal advantage that will accrue from the use of rifled ordnance, is the great certainty with which any object may be hit when fired at with them, since the shot deviates but little from its intended line of direction, and the gun is capable of being brought to bear upon the object, with great exactness, by means of the telescope and cross-hairs.
The other pieces of artillery commonly made use of Mortars are mortars, howitzers, and royals. The mortars described, are a kind of short cannon of a large bore, with chambers for the powder, and are made of brass or iron. Their use is to throw hollow shells filled with powder, which falling on any building, or into the works of a fortification, burst, and with their fragments destroy every thing near them. Carcases are also thrown out of them; which are a sort of shells with five holes, filled with pitch and other materials, in order to set buildings on fire; and sometimes baskets full of stones, of the size of a man's fist, are thrown out of them upon an enemy placed in the covert-way in the time of a siege. The ingenious General Desaguliers contrived to throw bags filled with grapeshot, containing in each bag from 400 to 600 shot of different dimensions, out of mortars. The effect of these is tremendous to troops forming the line of battle, passing a defile, or landing, &c. the shot pouring down like a shower of hail on a circumference of above 300 feet.
Mortars are chiefly distinguished by the dimensions of their bore; for example, a 13-inch mortar is one the diameter of whose bore is 13 inches, &c.—The land-mortars are those used in sieges, and in battles. They are mounted on beds, and both mortar and bed are transported on block carriages. There is likewise a kind of land mortars mounted on travelling carriages, invented by Count Buckeburgh, which may be elevated to any degree; whereas all the English mortars are fixed to an angle of 45°. This custom, however, does not appear to have any foundation in reason. In a siege, shells should never be thrown with an angle of 45 degrees, excepting in one case only; that is, when the battery is so far off, that they cannot otherwise reach the works: for when shells are thrown out of the trenches into the works of a fortification, or from the town into the trenches, they should have as little elevation as possible, in order not to bury themselves, but to roll along the ground, whereby they do much more damage, and occasion a much greater con- Practice. sternation among the troops, than if they sunk into the ground. On the contrary, when shells are thrown upon magazines, or any other buildings, the mortars should be elevated as high as possible, that the shells may acquire a greater force in their fall, and consequently do more execution.
There are other kinds of mortars, called partridge-mortars, hand-mortars, and firelock-mortars; which last are also called bombards. The partridge-mortar is a common one, surrounded with 13 other little mortars bored round its circumference, in the body of the metal; the middle one is loaded with a shell, and the others with grenades. The vent of the large mortar being fired, communicates its fire to the rest; so that both the shell and grenades go off at once. Hand-mortars were frequently used before the invention of cohorts. They were fixed at the end of a staff four feet and a half long, the other end being shod with iron to stick in the ground; and while the bombardier with one hand elevated it at pleasure, he fired it with the other. The firelock-mortars, or bombards, are small mortars fixed to the end of a firelock. They are loaded as all common firelocks are; and the grenade, placed in the mortar at the end of the barrel, is discharged by a flint-lock. To prevent the recoil hurting the bombardier, the bombard rests on a kind of halberd made for that purpose.
The chamber in mortars is the place where the powder is lodged. They are of different forms, and made variously by different nations; but the cylindric seems to be preferable to any other form.
The howitzer is a kind of mortar mounted on a field-carriage like a gun: it differs from the common mortars in having the trunnions in the middle, whereas those of the mortar are at the end. The construction of howitzers is as various and uncertain as that of mortars, excepting that the chambers are all cylindric. They are distinguished by the diameter of their bore; for instance, a 10-inch howitzer is that which has a bore of 10 inches diameter, and so of others. They were much more lately invented than mortars, and indeed are plainly derived from them.
Royals are a kind of small mortars, which carry a shell whose diameter is 5.5 inches. They are mounted on beds in the same way as other mortars.
Fig. 17. represents a mortar; and the names of its parts are as follow:
- **AB**, the whole length of the mortar. - **AC**, the muzzle. - **CD**, chase. - **DE**, reinforce. - **EF**, breech. - **GH**, trunnions. - **a**, vent. - **b**, dolphin. - **c d**, vent-astragal and fillets. - **d e**, breech-ring and ogee. - **f g**, reinforce-ring and ogee. - **g h**, reinforce-astragal and fillets. - **i k**, muzzle-astragal and fillets. - **k l**, muzzle-ring and ogee. - **l m**, muzzle-mouldings. - **n**, shoulders.
**Interior parts.**
- **o**, chamber. - **p**, bore. - **q**, mouth. - **r**, vent.
The mortar-beds are formed of very solid timber, and placed upon very strong wooden frames, fixed in such a manner that the bed may turn round. The fore part of those beds is an arc of a circle described from the centre on which the whole turns.
There are several instruments employed in the loading of cannon. The names of these are as follow:
1. The lantern or ladle, which serves to carry the powder into the piece, and which consists of two parts, viz. of a wooden box, appropriated to the caliber of the piece for which it is intended, and of a caliber and a half in length with its vent; and of a piece of copper nailed to the box, at the height of a half caliber.—This lantern must have three calibers and a half in length, and two calibers in breadth, being rounded at the end to load the ordinary pieces.
2. The rammer is a round piece of wood, commonly called a box, fastened to a stick 12 feet long, for the pieces from 12 to 33 pounds; and 10 for the 8 and 4 pounders; which serve to drive home the powder and ball to the breech.
3. The sponge is a long staff or rammer, with a piece of sheep or lamb skin wound about its end, to serve for scouring the cannon when discharged, before it be charged with fresh powder; to prevent any spark of fire from remaining in her, which would endanger the life of him who should lead her again.
4. Wad-screw consists of two points of iron turned serpent-wise, to extract the wad out of the pieces when one wants to unload them, or the dirt which had chanced to enter into it.
5. The botefeux are sticks two or three feet long, and an inch thick, split at one end, to hold an end of the match twisted round it, to fire the cannon.
6. The priming iron is a pointed iron rod, to clear the touch-hole of the pieces of powder or dirt; and also to pierce the cartridge, that it may sooner take fire.
7. The primer, which must contain a pound of powder at least, to prime the pieces.
8. The quoin of mire, which are pieces of wood with a notch on the side to put the fingers on, to draw them back or push them forward when the gunner points his piece. They are placed on the sole of the carriage.
9. Leaden plates, which are used to cover the touch-hole, when the piece is charged, lest some dirt should enter it and stop it.
Before charging the piece, it is well sponged, to clean it of all filth and dirt within-side; then the proper weight of gunpowder is put in and rammed down; care being taken that the powder be not bruised in ramming, which weakens its effect; it is then run over by a little quantity of paper, hay, or the like; and lastly, the ball is thrown in.
To point, level, or direct the piece, so as to play against any certain point, is done by the help of a quadrant.
The longest branch of this instrument is placed in the cannon's mouth, and elevated or lowered till the thread cuts the degree necessary to hit the proposed object. Which done, the cannon is primed, and then set fire to. The method by sector, however, proposed by Dr Lind, is certainly in all cases to be preferred.
A 24 pounder may very well fire 90 or 100 shots every day in summer, and 60 or 75 in winter. In case of necessity it may fire more; and some French officers of artillery assure us, that they have caused such a piece to fire every day 150 shots in a siege.—A 16 and a 12 pounder fire a little more, because they are easier served. There have even been some occasions where 200 shots have been fired from these pieces in the space of nine hours, and 138 in the space of firing. In quick firing, tubes are made use of. They are made of tin; and their diameter is two-tenths of an inch, being just sufficient to enter into the vent of the piece. They are about six inches long, with a cap above, and cut slanting below, in the form of a pen; the point is strengthened with some solder, that it may pierce the cartridge without bending. Through this tube is drawn a quick-match, the cap being fitted with mealed powder moistened with spirits of wine. To prevent the mealed powder from falling out by carriage, a cap of paper or flannel steeped in spirits of wine is tied over it. To range pieces in a battery, care must be taken to reconnoitre well the ground where it is to be placed, and the avenues to it. The pieces must be armed each with two lanterns or ladles, a rammer, a sponge, and two priming-irons. The battery must also be provided with carriages and other implements, necessary to remount the pieces which the enemy should chance to dismount.
To serve expeditiously and safely a piece in a battery, it is necessary to have to each a sack of leather, large enough to contain about 20 pounds of powder to charge the lanterns or ladles, without carrying them to the magazine; and to avoid thereby making those trains of powder in bringing back the lantern from the magazine, and the accidents which frequently happen thereby.
A battery of three pieces must have 30 gabions, because six are employed on each of the two sides or epaulements, which make 12, and nine for each of the two merlons.
There ought to be two gunners and six soldiers to each piece, and an officer of artillery.
The gunner posted on the right of the piece must take care to have always a pouch full of powder and two priming irons; his office is to prime the piece, and load it with powder. The gunner on the left fetches the powder from the little magazine, and fills the lantern or ladle which his comrade holds; after which, he takes care that the match be very well lighted, and ready to set fire to the piece at the first command of the officer.
There are three soldiers on the right and three on the left of the piece. The two first take care to ram and sponge the piece each on his side. The rammer and sponge are placed on the left, and the lantern or ladle on the right. After having rammed well the wad put over the powder and that put over the bullet, they then take each a handspike, which they pass between the foremost spokes of the wheel, the ends whereof will pass under the head of the carriage, to make the wheel turn round, leaning on the other end of the handspike, towards the embrasure.
It is the office of the second soldier on the right to provide wad, and to put it into the piece, as well over the powder as over the bullet; and that of his comrade on the left to provide 50 bullets, and every time the piece is to be charged to fetch one of them and put it into the piece after the powder has been rammed. Then they both take each a handspike, which they pass under the hind part of the wheel, to push it in battery.
The officer of artillery must take care to have the piece diligently served.
In the night he must employ the gunners and soldiers, who shall relieve those who have served 24 hours, to repair the embrasures.
If there be no water near the battery, care must be taken to have a cask filled with it, in which to dip the sponges and cool the pieces every 10 or 12 rounds.
The carriage for a mortar of 12 inches diameter must be 6 feet long, the flasks 12 inches long and 10 thick. The trunions are placed in the middle of the carriage.
The carriage of an 18 inch mortar must be 4 feet long, and the flasks 11 inches high and 6 thick.
To mount the mortars of new invention, they use carriages of cast iron.
In Germany, to mount mortars from 8 to 9 inches, Method of and carry them into the field, and execute them horizontally as a piece of cannon, they make use of a piece of wood 8 feet 2 inches long, with a hole in the middle to lodge the body of the mortar and its trunions as far as their half diameter, and mounted on two wheels four feet high, to which they join a vantrain proportioned to it, and made like those which serve to the carriages of cannons.
Having mounted the mortar on its carriage, the next thing is to caliber the bomb by means of a great caliber, the two branches whereof embrace the whole circumference of the bomb: these two branches are brought on a role where the different calibers are marked, among which that of the bomb is found.
If no defect be found in the bomb, its cavity is filled, by means of a funnel, with whole gunpowder; a little space or liberty is left, that when a fusee or wooden tube, of the figure of a truncated cone, is driven through the aperture (with a wooden mallet, not an iron one for fear of accident), and fastened with a cement made of quicklime, ashes, brick-dust, and steel-filings, worked together in a glutinous water, or of four parts of pitch, two of colophony, one of turpentine, and one of wax, the powder may not be bruised. This tube is filled with a combustible matter made of two ounces. Practice ounces of nitre, one of sulphur, and three or more of gunpowder dust well rammed. See Fusee.
This fusee set on fire burns slowly till it reaches the gunpowder, which goes off at once, bursting the shell to pieces with incredible violence. Special care, however, must be taken that the fusee be so proportioned as that the gunpowder do not take fire ere the shell arrives at the destined place; to prevent which, the fusee is frequently wound round with a wet clammy thread.
Batteries consist,—1. Of an epauletment to shelter the mortars from the fire of the enemy. 2. Of platforms on which the mortars are placed. 3. Of small magazines of powder. 4. Of a boyau, which leads to the great magazine. 5. Of ways which lead from the battery to the magazine of bombs. 6. Of a great ditch before the epauletment. 7. Of a berm or retraite.
The platforms for mortars of 12 inches must have 9 feet in length and 6 in breadth.—The lambourds for common mortars must be four inches thick; those of a concave chamber of 8lb. of powder, 5 inches; those of 12lb. 6 inches; those of 18lb. 7 inches or thereabouts. Their length is at discretion, provided there be enough to make the platforms 9 feet long.—The fore part of the platform will be situated at two feet distance from the epauletment of the battery.—The bombardiers, to shelter themselves in their battery, and not be seen from the town besieged, raise an epauletment of 7 feet or more high, which epauletment has no embrasures.
To serve expeditiously a mortar in battery, there are required,—five strong handspikes; a dame or rammer, of the caliber of the conic chamber, to ram the wad and the earth; a wooden knife a foot long, to place the earth round the bomb; an iron scraper two feet long, one end whereof must be four inches broad and roundwise, to clean the bore and the chamber of the mortar, and the other end made in form of a spoon to clean the little chamber; a kind of brancard to carry the bomb, a shovel, and pick-axe.
The officer who is to mind the service of the mortar must have a quadrant to give the degrees of elevation.
Five bombardiers, or others, are employed in that service; the first must take care to fetch the powder to charge the chamber of the mortar, putting his priming-iron in the touch-hole before he charges the chamber; and never going to fetch the powder before he has asked his officer at what quantity of powder he designs to charge, because more or less powder is wanted according to the distance where it is fired; the same will take care to ram the wad and earth, which another soldier puts in the chamber.
The soldier on the right will put again two shovelful of earth in the bottom of the bore, which should be likewise very well rammed down.
This done, the rammer or dame is returned into its place against the epauletment on the right of the mortar: he takes an handspike in the same place to post himself behind the carriage of the mortar, in order to help to push it into battery: having laid down his handspike, he takes out his priming-iron, and primes the touch-hole with fine powder.
The second soldier on the right and left will have by that time brought the bomb ready loaded, which must be received into the mortar by the first soldier, and placed very strait in the bore or chase of the mortar.
The first on the right will furnish him with earth to put round the bomb, which he must take care to ram close with the knife given him by the second on the left.
This done, each shall take a handspike, which the two first on the right and left shall put under the pegs of retreat of the fore part, and the two behind under those of the hind part, and they together push the mortar in battery.
Afterwards the officer points or directs the mortar.
During that time the first soldier takes care to prime the touch-hole of the mortar, without ramming the powder; and the last on the right must have the match ready to set fire to the fusee of the bomb on the right, while the first is ready with his on the left to set fire to the touch-hole of the mortar, which he ought not to do till he sees the fusee well lighted.
The foremost soldiers will have their handspikes ready to raise the mortar upright as soon as it has discharged, while the hindmost on the left shall with the scraper clean the bore and chamber of the mortar.
The magazine of powder for the service of the battery must be situated 15 or 20 paces behind, and covered with boards and earth over it.—The loaded bombs are on the side of the same magazine, at five or six paces distance.
The officer who commands the service of the mortar must take care to discover as much as possible with the eye the distance of the place where he intends to throw his bomb, giving the mortar the degree of elevation according to the judgment he has formed of the distance. Having thrown the first bomb, he must diminish or increase the degrees of elevation according to the place upon which it shall fall. Several make use of tables to discover the different distances according to the differences of the elevations of the mortar, especially the degrees of the quadrant from 1 to 45°; but these, from the principles already laid down, must be fallacious.
The petard is the next piece of artillery which deserves our attention; and is a kind of engine of metal, somewhat in shape of a high-crowned hat, serving to break down gates, barricades, draw-bridges, or the like works, which are intended to be surprised. It is very short, narrow at the breech and wide at the muzzle, made of copper mixed with a little brass, or of lead with tin.
The petards are not always of the same height and bigness: they are commonly 10 inches high, 7 inches of diameter a-top, and 10 inches at bottom. They weigh commonly 40, 45, and 50 pounds.
The madrier, on which the petard is placed, and where it is tied with iron circles, is of two feet for its greatest width, and of 18 inches on the sides, and no thicker than a common madrier. Under the madrier are two iron bars passed crosswise, with a hook, which serves to fix the petard.
To charge a petard 15 inches high, and 6 or 7 inches of caliber or diameter at the bore, the inside must be first very well cleaned and heated, so that the hand may bear the heat; then take the best powder that may be found, throw over it some spirit of wine,