Part 4

28—10 Inch mortars, on iron beds, at 50 shells each per day, for the whole siege. 3lbs. of powder charge—2lbs. 10 oz. for bursting.

_Pound shot_—100 to a charge; 50 rounds per mortar each day for 10 mortars 7 days; 2 lbs. of powder each.

_Hand grenades_—25 to a charge; the same as the pound shot.

_Carcasses, round_—1 per mortar, per day.

8— 8 Inch howitzers, on travelling carriages

30 _Shells_ for each per day, during the siege.

_Case shot_—5 rounds per day each.

_Carcasses_—1 per day each.

_Powder_—1 lb. per charge; 1 lb. 14 oz. for bursting.

20—5½ Inch mortars, on wooden beds.

50 _Shells_ for each, per day, for the whole siege; charge 8 oz.—12 oz. for bursting.

_Flannel cartridges_, for ⅓ the number of rounds.

_Tin_ tubes in the same proportion.

_Portfires_, ½ the number of rounds with tubes.

_Fuzes_, ⅒ to spare.

_Match_, 50 cwt.

Spare carriages for 24 Prs. seven. 2 Devil carriages. 6 Sling carts. 6 Block carriages. 3 Forge carts. 3 Store waggons, with iron and coals. 3 Triangle gins, complete. 6 Laboratory tents. 2 Small petards. 4 Grates for heating shot.

_Of the Arrangement of Artillery at a Siege._

The first arrangement of the artillery at a siege is to the different batteries raised near the first parallel, to enfilade the faces of the work on the front attacked, which fire on the approaches. If these first batteries be favorably situated, the artillery may be continued in them nearly the whole of the siege; and will save the erection of any other gun batteries, till the besiegers arrive on the crest of the glacis. It however frequently happens, from local circumstances, that the besiegers cannot avail themselves of the most advantageous situations for the first batteries. There are four situations from which the defences of any face may be destroyed; but not from all with equal facility. The best position for the first batteries, is perpendicular to the prolongation of the face of the work to be enfiladed. If this position cannot be attained, the next that presents itself is, on that side of the prolongation which takes the face in reverse; and under as small an angle as possible. From both these positions the guns must fire _en ricochet_. But if the ground, or other circumstance, will not admit of either of these being occupied by ricochet batteries, the battery to destroy the fire of a face must be without the prolongation, so as to fire obliquely upon the outside of the face. The last position, in point of advantage, is directly parallel to the face. From these two last positions the guns must fire with the full charges.

The second, or breaching batteries at a siege, are generally placed on the crest of the glacis, within 15 or 18 feet of the covert way; which space serves as the epaulment: but if the foot of the revetment cannot be seen from this situation, they must be placed in the covert way, within 15 feet of the counterscarpe of the ditch. These batteries must be sunk as low as the soles of the embrazures, and are in fact but an enlargement of the sap, run for the lodgement on the glacis or in the covert way. In constructing a battery on the crest of the glacis, attention must be paid that none of the embrazures open upon the traverses of the covert way. These batteries should consist of at least four guns; and if the breadth between the traverses will not admit of this number, at the usual distances, the guns must be closed to 15 or 12 feet from each other.

The mortars are generally at first arranged in battery, adjoining the first gun batteries, or upon the prolongation of the capitals of the works; in which place they are certainly least exposed. Upon the establishment of the half parallels, batteries of howitzers may be formed in their extremities, to enfilade the branches of the covert way; and upon the formation of the third parallel, batteries of howitzers and stone mortars may be formed to enfilade the flanks of the bastions, and annoy the besieged in the covert way. In the lodgement on the glacis, stone and other mortars may also be placed, to drive the besieged from their defences. A great object in the establishment of all these batteries, is to make such an arrangement of them, that they mask the fire of each other as little as possible; and particularly of the first, or ricochet batteries. This may very well be prevented till the establishment on the crest of the glacis, when it becomes in some degree unavoidable: however, even the operations on the glacis may be so arranged, that the ricochet batteries be not masked till the breaching batteries be in a great state of forwardness: a very secure method, and which prevents the soldiers in trenches being alarmed by the shot passing over their heads, is to raise a _Parados_, or parapet, in the rear of the trenches, at such parts where the fire from the besieger’s batteries crosses them. For further details on this subject, and for the manner of constructing batteries, see the word _Battery_; also the words _Ricochet_, _Breach_, _Magazine_, _Platform_, &c.

3d. _Artillery and Ammunition for the Defence of Fortified Place._

_It is usual in an Estimate of Artillery and Ammunition for the Defence of Fortified Places, to divide them into Eight Classes, as follows_:

+-----------------------+-----+-----+----+----+----+----+----+----+ |CLASSES. | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | +-----------------------+-----+-----+----+----+----+----+----+----+ |Garrisons |12000|10000|8000|5000|3500|2500|1600| 400| |Cannon | 100| 90| 80| 70| 60| 50| 40| 30| |Triangle Gins | 4| 3| 2| 2| 2| 1| 1| 1| |Sling Carts | 4| 3| 2| 2| 2| 1| 1| 1| |Jacks of Sizes | 4| 3| 2| 2| 2| 1| 1| 1| |Truck Carriages | 6| 6| 4| 4| 2| 2| 2| 2| |Ammunition Carts, &c. | 12| 12| 12| 6| 6| 6| 2| 2| |Tools for Pioneers | 9000| 6000|5000|4000|3500|3000|1000|1000| | ” ” Miners | 300| 200| 100| 100| 100| 100| 50| 5| +----------+------------+-----+-----+----+----+----+----+----+----+ |Tools for | ⅓ Axes | | | | | | | | | | Cutting | ⅔ Billhooks| 1200| 900| 600| 500| 450| 300| 150| 150| +----------+------------+-----+-----+----+----+----+----+----+----+ |Forges, complete | 6| 4| 2| 2| 2| 2| 1| 1| +-----------------------+-----+-----+----+----+----+----+----+----+

The guns will be of the following calibers: ⅓ of 18 Prs.—⅓ of 12 Prs.—and ⅓ of 24, 9, and 4 Pounders in equal proportions. If the place does not possess any very extraordinary means of defence, it will be very respectably supplied with 800 rounds of ammunition per gun for the two larger calibers, and 900 for each of the others.

_Gun Carriages_—⅓ more than the number of guns.

_Mortars_—About ¼ the number of guns in the three first classes; and ⅕ or ⅙ in the other classes. Of these ⅖ will be 13 or 10 inch mortars, and the rest of a smaller nature.

_Howitzers_—¼ the number of mortars.

_Stone Mortars_—⅒ the number of guns.

_Shells_—400 for each of the 10 and 13 inch mortars, and 600 for each of the smaller ones.

_Beds_ for mortars—⅓ to spare.

_Carriages_ for howitzers—⅓ to spare.

_Hand Grenades_—4 or 5000 for the two first classes; 2000 in the three following classes; and from 1500 to 600 in the three last classes.

_Rampart Grenades_—2000 for the first class; 1000 for the four following classes; and 500 for the sixth class; none for the two last.

_Fuzes_—¼ more than the number of shells.

_Bottoms_ of wood for stone mortars—400 per mortar.

_Sand Bags_—500 for every piece of ordnance in the large places, and ¼ less in the small ones.

_Handspikes_—10 per piece.

_Tackle Falls_ for gins—1 for every 10 pieces to spare.

_Musquets_—1 per soldier, and the same number to spare.

_Pistols_, pairs—½ the number of musquets.

_Flints_—50 per musquet, and 10 per pistol.

_Lead_ or _Balls_ for small arms—30 pounds per musquet.

_Powder for Small Arms_—5 pounds for every musquet in the garrison, including the spare ones.

The above proportions are taken from Durtubie’s Manuel De l’Artilleur.

The following method of regulating the management of the artillery, and estimating the probable expenditure of ammunition in the defence of a fortified place, is extracted from a valuable work on fortification lately published at Berlin. It is particularly applied to a regular hexagon; the siege is divided into three periods, _viz._

1st. From the first investiture to the first opening of the trenches, about 5 days.

2d. From the opening of the trenches to the effecting a lodgement on the glacis, about 18 days.

3d. From this time to the capitulation, about 5 days.

_First Period._ Three guns on the barbette of each bastion and on the barbettes of the ravelins in front of the gateways, half 24 Prs. and half 18 Prs.[4] three 9 Prs. on the barbette of each of the other ravelins.

Twelve 12 Prs. and twelve 4 Prs. in reserve.

One 13 inch mortar in each bastion.

Six of 8 inch in the salient angles of the covert way.

Do. in reserve.

Ten stone mortars.

[4] For 16 Prs. in the French work, the compiler has said 18 Prs.—for 8 Prs. 9 Prs.—for 12 inch mortars, 13 inch; to which they nearly answer.

The 12 Prs. in reserve, are to be ranged behind the curtain, on whichever side they may be required, and the 4 Prs. in the outworks; all to fire _en ricochet_ over the parapet. By this arrangement, the whole of the barbette guns are ready to act in any direction, till the side of attack is determined on; and with the addition of the reserve, 49 pieces may be opened upon the enemy the very first night they begin to work upon the trenches.

The day succeeding the night on which the trenches are opened, and the side to be attacked determined, a new arrangement of the artillery must take place. All the 24 and 18 Prs. must be removed to the front attacked, and the other bastions, if required, supplied with 12 Prs. The barbettes of the bastions on this front may have each 5 guns, and the 12 18 prs. may be ranged behind the curtain. The six mortars in reserve must be placed, two in each of the salient angles of the covert way of this front, and with those already there, mounted as howitzers,[5] to fire down the prolongations of the capitals. Three 4 pounders in each of the salient places of arms of the ravelins on the attacked fronts, to fire over the palisading, and five 9 Prs. in the ravelin of this front. This arrangement will bring 47 guns, and 18 mortars to fire on the approaches after the first night; and with a few variations will be the disposition of the artillery for the second period of the siege. As soon as the enemy’s batteries are fairly established, it will be no longer safe to continue the guns _en barbette_, but embrazures[6] must be opened for them; which, embrazures must be occasionally masked, and the guns assume new directions, as the enemy’s fire grows destructive; but may again be taken advantage of, as circumstances offer. As the enemy gets near the third parallel, the artillery must be withdrawn from the covert way to the ravelins, or to the ditch, if dry, or other favorable situations; and, by degrees, as the enemy advances, to the body of the place. During this period of the siege, the embrazures must be prepared in the flanks, in the curtain which joins them, and in the faces of the bastions which flank the ditch of the front ravelins. These embrazures must be all ready to open, and the heavy artillery mounted in them, the moment the enemy attempts a lodgement on the glacis.

[5] Our iron mortars, on iron beds, all admit of being fired at low angles.

[6] A German author proposes that the mounds of earth which enable the guns to fire _en barbette_, should be so arranged, that the embrasures may be opened between them; and when the guns descend to the embrazures, the barbettes will serve as traversers.

Every effort should be made to take advantage of this favorable moment, when the enemy, by their own works, must mask their former batteries, and before they are able to open their new ones.

The expenditure of ammunition will be nearly as follows:

_First period_ of the siege—5 rounds per gun, per day, with only half the full charge, or ⅙ the weight of the shot, and for only such guns as can act.

_Second period_—20 rounds per gun, per day, with ⅙ the weight of the shot.

_Third period_—60 rounds per gun, per day, with the full charge, or ⅓ the weight of the shot.

_Mortars_—At 20 shells per day, from the first opening of the trenches to the capitulation.

_Stone Mortars_—80 rounds per mortar, for every 24 hours, from the establishment of the demi parallels to the capitulation; about 13 days.

_Light_, and _Fire balls_—Five every night, for each mortar, from the opening of the trenches to the eighth day, and three from that time to the end

These amount to about 700 for guns. 400 for mortars. 1000 for stone do.

This proportion and arrangement is however made upon a supposition, that the place has no countermines to retard the progress of the besiegers, to a period beyond what is abovementioned; but the same author estimates, that a similar place, with the covert way properly countermined beforehand, and those countermines properly disputed, may retard a siege at least 2 months; and that if the other works be likewise effectually countermined and defended, the siege may be still prolonged another month.

The above proportion is therefore to be further regulated, as the strength of the place is increased by these or any other means. These considerations should likewise be attended to, in the formation of an estimate of ammunition and stores for the siege of a fortified place. See _Carriage, Platform, Park_, and the different natures of artillery, as _Gun, Mortar, Howitzer_, &c.

The small arms ammunition is estimated by this author as follows:

¼ of a pound of gunpowder, or 10 rounds per day, per man, for all the ordinary guards.

1¼ lbs. or 50 rounds per man, per 12 hours, for all extraordinary guards.

⅝ of a pound, or 25 rounds for every man on picket, during the period of his duty.

_AXLETREES_—See the word _Carriages_.

_BALLS_—of lead, of different natures.

+--------------+--------+----------+--------------+ | | Number | Diameter | Number made | | Nature. | to one | in | from one ton | | | Pound. | Inches. | of Lead. | +--------------+--------+----------+--------------+ |Wall pieces | 6¾ | .89 | 14,760 | |Musquets | 14½ | .68 | 32,480 | |Carbine | 20 | .60 | 44,800 | |Pistol | 34 | .51 | 78,048 | |7 Barrel guns | 46½ | .46 | 104,160 | +--------------+--------+----------+--------------+

Lead balls are packed in boxes containing each 1 cwt. About 4 pounds of lead in the cwt. are generally lost in casting. See _Shot_.

_BARRELS for powder_--Their dimensions.

+--------------------+----------+----------+----------+ | | Whole | Half | Quarter | | | Barrels. | Barrels. | Barrels. | | +----------+----------+----------+ | | Ft. In. | Ft. In. | Ft. In. | +--------------------+----------+----------+----------+ |Depth | 1 9.61 | 1 5.13 | 1 2.25 | |Diameter at top | 1 3.61 | 1 0.37 | 9.35 | | ” at bulge | 1 5.36 | 1 2. | 10.71 | | ” at bottom | 1 3.51 | 1 0.31 | 9.41 | +--------------------+----------+----------+----------+

The whole barrels are made to contain 100 pounds, and the half barrels 50 pounds of powder; but of late only 90 pounds have been put into the barrels, and 45 into the half barrels; which, by leaving the powder room to be shifted, preserves it the better.

_Budge Barrels_ contain 38 lbs.

Weight of barrel—copper hooped—10 lbs. ” ” hazle hooped—6 Length of barrel 10½ inches. Diameter 1 foot 1 inch.

_BASKETS._—Ballast, ½ bushel—weight, 5 lbs. Diameter, 1 foot 6 inches—length, 1 foot.

_BATTERY._—_Dimensions of Batteries._

1. _Gun Batteries._—Gun Batteries are usually 18 feet per gun. Their principal dimensions are as follow:

_Ditch._—Breadth 12 feet. Depth 8

NOTE. These dimensions give for a battery of two guns 3456 cubic feet of earth; and must be varied according to the quantity required for the epaulment.

_Epaulment._—Breadth at bottom 23 feet. ” at top 18 Height within 7 ” without 6 ft. 4 in. Slope, interior ²/₇ of height. ” exterior ½ of height.

NOTE. The above breadths at top and bottom are for the worst soil; good earth will not require a base of more than 20 feet wide, which will reduce the breadth at top to 15 feet; an epaulment of these dimensions for two guns will require about 4200 cubic feet of earth, and deducting 300 cubic feet for each embrazure, leaves 3600 required for the epaulment. In confined situations the breadth of the epaulment may be only 12 feet.

_Embrazures._—Distance between } 18 feet. their centers } Openings, interior 20 inches. ” exterior 9 feet.

Height of the sole above the platform 32 inches.

NOTE. Where the epaulment is made of a reduced breadth, the openings of the embrazures are made with the usual breadth within, but the exterior openings proportionally less. The embrazures are sometimes only 12 feet asunder, or even less when the ground is very confined. The superior slope of the epaulment need be very little, where it is not to be defended by small arms. The slope of the sole of the embrazures must depend upon the height of the object to be fired at. The _Berm_ is usually made 3 feet wide, and where the soil is loose, this breadth is increased to 4 feet.

2. _Howitzer Batteries._—The dimensions of howitzer batteries are the same as those for guns, except that the interior openings of the embrazures are 2 feet 6 inches, and the soles of the embrazures have a slope inwards of about 10 degrees.

3. _Mortar Batteries_—Are also made of the same dimensions as gun batteries, but an exact adherence to those dimensions is not so necessary. They have no embrazures. The mortars are commonly placed 15 feet from each other, and about 12 feet from the epaulment.

NOTE. Though it has been generally customary to fix mortars at 45°, and to place them at the distance of 12 feet from the epaulment, yet many advantages would often arise from firing them at lower angles; and which may be done by removing them to a greater distance from the epaulment, but where they would be in equal security. If the mortars were placed at the undermentioned distances from the epaulment, they might be fired at the angles corresponding:

At 13 feet distance for firing at 30 degrees. 21 ” ” 20 30 ” ” 15 40 ” ” 10 over an epaulment of 8 feet high.

A French author asserts, that all ricochet batteries, whether for howitzers or guns, might be made after this principle, without the inconvenience of embrazures; and the superior slope of the epaulment being inwards instead of outwards, would greatly facilitate this mode of firing.

If the situation will admit of the battery being sunk, even as low as the soles of the embrazures, a great deal of labour may be saved. In batteries without embrazures, this method may almost always be adopted; and it becomes in some situations absolutely necessary in order to obtain earth for the epaulment; for when a battery is to be formed on the crest of the glacis, or on the edge of the counterscarpe of the ditch, there can be no excavation but in the rear of the battery.

4. _Batteries on a Coast_—generally consist of only an epaulment, without much attention being paid to the ditch: they are, however, sometimes made with embrazures, like a common gun battery; but the guns are more generally mounted on traversing platforms, and fire over the epaulment. When this is the case, the guns can seldom be placed nearer than 3½ fathoms from each other. The generality of military writers prefer low situations for coast batteries; but M. Gribauvale lays down some rules for the heights of coast batteries, which place them in such security, as to enable them to produce their greatest effect. He says the height of a battery of this kind, above the level of the sea, must depend upon the distance of the principal objects it has to protect or annoy. The shot from a battery to ricochet with effect, should strike the water at an angle of about 4 or 5 degrees at the distance of 200 yards. Therefore the distance of the object must be the radius, and the height of the battery the tangent to this angle of 4 or 5°; which will be, at the above distance of 200 yards, about 14 yards. At this height, he says, a battery may ricochet vessels in perfect security; for their ricochet being only from a height of 4 or 5 yards, can have no effect against the battery. The ground in front of a battery should be cut in steps, the more effectually to destroy the ricochet of the enemy. In case a ship can approach the battery so as to fire musquetry from her tops, a few light pieces placed higher up on the bank, will soon dislodge the men from that position, by a few discharges of case shot. It is also easy to keep vessels at a distance by carcasses, or other fire balls, which they are always in dread of.

DURTUBIE estimates, that a battery of 4 or 5 guns, well posted, will be a match for a first rate man of war.

_To estimate the Materials for a Battery._

Fascines of 9 feet long are the most convenient for forming a battery, because they are easily carried, and they answer to most parts of the battery without cutting. The embrazures are however better lined with fascines of 18 feet. The following will be nearly the number required for a fascine battery of two guns or howitzers:

90 fascines of 9 feet long.

20 fascines of 18 feet—for the embrazures.

This number will face the outside as well as the inside of the epaulment, which if the earth be stiff, will not always be necessary; at least not higher than the soles of the embrazures on the outside. This will require five of 9 feet for each merlon less than the above.

A mortar battery will not require any long fascines for the lining of the embrazures. The simplest method of ascertaining the number of fascines for a mortar battery, or for any other plain breast work, is to divide the length of work to be fascined in feet, by the length of each fascine in feet, for the number required for one layer, which being multiplied by the number of layers required, will of course give the number of fascines for facing the whole surface. If a battery be so exposed as to require a shoulder to cover it in flank, about 50 fascines of 9 feet each will be required for each shoulder.

Each fascine of 18 feet will require 7 pickets. ” ” ” 9 feet ” ” 4 ”

12 workmen of the line, and 8 of the artillery, are generally allotted to each gun.