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CHAPTER
XIII.
ON
THE ATTACK AND DEFENSE OF FORTIFIED PLACES.
SIEGES-- The siege of fortified places has always consisted in destroying the defenses from a distance, by means of large projectile machines, and effecting a breach in the wall for the purpose of entering the place.
In the early days of artillery, when defensive walls were
very hih, they were battered in breach with stone balls from twelve to twenty
-five inches in diameter, after which the ditch was filled up, and the place
stormed. Mention is made of such balls at the siege of Metz, in the latter part
of the fourteenth century.
The walls having been lessened in height, and supported
behind with an earthen embankment, it was no longer possible to form the breach
from a distance, and the use of stone balls having been abandoned, mines were
resorted to for the purpose of blowing down the walls.
Cast-iron balls then coming into use, they were employed to
make cuts in the masonry, instead of battering it down as formerly. This method,
first invented by the Turks, was improved by Vauban, whose experience showed him
that the breaches so formed were more regular and made more rapidly than by the
use of mines.
Up to that period, the fire of the artillery, directed upon
the pieces of the besieged, and the interior edifices, expended its effect more
upon the inclosed cities than upon the fortifications surrounding them. The
ricochet fire was employed with full edict at this time in dismounting the
enemy's pieces; and the war of sieges was carried to the highest perfection
under its illustrious founder.
A besieging army is generally divided into two corps, one
charged with the siege, the other with holding the surrounding country, for a
short distance from the place. Sometimes the besieging army is covered by a
corps of observation, in which case there is no necessity for its being so
numerous as when it acts alone.
The artillery necessary for the attack of a place
constitutes what is called a siege –equipage or train. The strength of it
depends upon the importance of the place to be attacked, and the resources at
hand. For besieging the strongest places, the French prescribe an equipage of
–
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40 24-pd. guns. 15c mortars (8.78in.)
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40 10-pd. (U. S. 18). 12 stone mortars.
-
40 22c howitzers (8.78in.) 12 15c mortars (5.95 in.), and
-
15 27c mortars (10.79in.). 60 rampart muskets.
A double attack would require about 200 cannon. The largest
guns and howitzers, and smallest mortars, are provided with about 1,000 rounds
of ammunition each. The large mortars with 750 rounds, and the stone mortars
with 500 rounds.
In this country, where the permanent works are so different
from those in Europe, it is difficult to lay down any positive rules for the
formation of siege equipages. The number and kind of pieces must be determined
by the circumstances of each case, taking into consideration the strength,
position, and condition of the place to be attacked. For the general principles
on which estimates for a siege train are made, see Ordnance Manual, pp. 332-3.
An army, no matter how large, seldom carries along with it
all the necessary means for a siege; and when fortified places obstruct the
march, the attack is carried on with such pieces
as can be obtained from the adjacent places in our possession; and generally the
means made use of at sieges are far below the estimate which would be made were
everything to be had close at hand.
Permanent works can be reduced only by the heaviest siege
pieces, such as 18 and 24 -pd. guns, 8-in. howitzers and mortars. The amount of
ammunition will of course vary according to circumstances. If possible, the 18
and 24 -pdrs. should be furnished with 1,000 rounds; the 12-pdrs. with a greater
number. The 8 -in. howitzers and mortars with 800, and the coehorn and 10-in.
mortars with 600. Each gun should be provided, in addition, with 50
rounds of grape and canister, and 100 of spherical -case shot.
Military Reconnaissances .- On approaching a fortified place during a march, or in
endeavoring to ascertain the position and force of the enemy, the resources of
the country, &c., frequent reconnaissances leave to be made. These are of
three different kinds:
1st. The daily reconnaissances necessary for the safety of
the camps, posts, &c. Their object is to discover the movements and
preparations of the enemy, and the disposition of his advanced. posts. They are
made by small detachments, and by patrols from the main guard.
They should not be made at the same labour every day, nor by
the same routes.
2d. Special reconnaissances designed to ascertain -- the
topography of the country, and the means which it can furnish for attack and
defense; the position of the enemy, and his strength at different points; and in
fine, to furnish the information necessary for the determination of the method
of operating, moving the different columns, &c. These reconnaissances are
conducted in accordance with instructions from the general -in-chief, the
commander of separate corps, divisions, &c.
3d. Offensive reconnaissances, which ordinarily should be
ordered only by the general-in-chief; for the purpose of ascertaining as
accurately as possible, the position and strength of the energy.
The result of every reconnoissance should be presented in a
clear, simple, and positive report. The officer making it, must expressly
distinguish between what he has seen himself, and what he has learned from
others without being able himself to verify the accuracy of it.
He adds to the report, the drawings necessary to represent
the ground, the positions of the enemy, &c. Troops making a reconnoissance, the object of which is simply
to see and observe, should not become compromised or even seen; they should move
with precaution, have an advance-guard and scouts out, and become engaged only
when forced to it, in order to make prisoners when there is no other means of
obtaining information, or when they encounter the enemy marching against their
camp; in which case they give warning by preconcerted signals, such as a burning
hay -stack, bonfires, &c.
To examine an enemy, choose the morning, when everything in
his camp is in motion; observe the camp -fires, the defensive works, the
position of the parks, cavalry, &c. Take up a position on the flank of his
column, and count the number of his battalions, squadrons, and batteries; note
the space which they occupy, the time they take to march past, and the order of
march.
For the topography, establish in advance, from the maps of
the country, rough sketches upon a scale large enough to be able to figure in
details at sight, and to delineate various distances and differences of level.
Telescopes and compasses should be carried along with the party, which should
also be furnished with good guides.
In making a reconnaissance without instruments, the survey
is, of course, much less exact than when they are used. The distances are often
unmeasured by the pace, and many details inserted in the sketch, estimated
simply by the eye.
A rough sketch is first made from the maps of the country.
If the ground is open, a high level position is chosen, from which a great
extent of country can be viewed; when practicable distances are measured with
the chain, large triangles are formed in such a way as to obtain points near the
centre of the sketch, and these points are afterwards made use of to form
smaller triangles, by intersections, offsets, &c. The intermediate details
are inserted from the step and the eye.
In a wooded country, the method of examining with the eye
and step is often the only practicable way of making the survey. To lessen the
errors as much as possible, the principal lines of direction should be
determined with care, as well as the points in which they intersect, and the
sides of the inclosing perimeter multiplied with the compass, so as to verify
the result.
The configuration of the ground is of essential importance
in a military reconnoissance, in order to determine a proper distribution and
employment of the different arms, and the positions for batteries, from a
knowledge of the inclination of the slopes, the height of the hills, &c.
The principles laid down for making a regular survey should be followed as much as possible, in forming the map. If pressed for time, the conventional tints may be replaced by initial letters. Paths are represented by a single line, which should always be of the same size, and the thickness proportional to their importance. Roads are represented by two lines.
Streams, which can be represented only by a single line, are
marked in blue, which is increased in width, as the distance from the source
increases.
The most important slopes to be indicated on a map, are:
1st.
Those of 60º, which are inaccessible to men, and have a base of 4 to a height
of 7 units.
2d.
Those of 45º, which are difficult for men, and have a base of 1 to a height of
1.
3d.
Those of 30º, which are inaccessible to horses, and have a base of 7 to a
height of 4.
4th.
Those of 15 º, easy accessible for carriages, and have a base of 12 to a height
of 1.
The maximum inclination assumed by falling earth, in a
mountainous country, is a slope of 100 base to a height of 71.
Masonry constructions are traced in red. Roads, paths,
dikes, wooden bridges, isolated trees, wooden wind-mills, batteries, and
entrenchments, in Indian ink. The different hinds of soil and cultivated ground,
masses of houses, and water, are represented by conventional tints.
The colors employed are, India ink, carmine, gamboge,
indigo, and sepia. Masonry constructions are colored in carmine; rivers and
streams, in blue; forests, in yellow, merging on a green, composed of gamboge
and a very little indigo -- the wet portions filled in with blue, like water;
meadows in green, composed of indigo and gamboge. Marshy meadows are represented
by breaking up the green, and filling in the open portions with a blue tint like
water. Orchards have the same tint as meadows, and are regularly dotted over to
represent the trees. Heath is made of a lighter blue than meadow land, and
slightly diversified with red on another brush. Marshes are tinted like meadows,
but with the wet portions filled in with blue. Untilled ground with a lighter
blue than meadows, and slightly diversified with a, color formed of gamboge and
a little carmine, like sand. Vineyards with a violet color made of Indian ink,
carmine, and indigo. Sand, with gamboge and a little carmine. Lines of troops
are represented by short parallel lines filled in with blue.
The writing on the map is made in Indian ink. The altitude
figures, the names of towns, cities, and dwellings, are written alongside, upon
perpendiculars to the meridian, the north being placed above; those of rivers,
streams, roads, and canals parallel to the directions in which these run. The
roads going beyond the limits of the survey should be marked with the largest
place to which they lead.
The names of cities are put in in upright capitals; those of
market -towns in inclined capitals; wooden villages, in upright roman; hamlets
and marshes in inclined roman; citadels, large rivers, and canals, in small
inclined capitals; forts, small rivers, ponds, castles, and roads, in small
upright roman capitals; mineral springs in italics; and farms, inns,
manufactories, mills, paths, and small streams, in small italics.
In the field, if there is not time to form a topographical
map, with pen -shading, &c., the ground may be figured with the stump or
pencil, deeper tints being employed where the slopes are more rapid.
The principal mountain -chains which serve as a defense to a
district of country should be distinctly marked, as well as the different
branches which defend or favor the access to it. Note their direction with the
compass, as also the relative heights of the different parts, if they are
sufficiently extended to enable a plan of defense to be formed. Observe the
communications to be preserved, the roads to be destroyed, and any other means
of annoying the enemy; the proper positions for camps or entrenchments; the
slopes, forests, rocks, &c.
A mountainous or hilly country, partly wooded, partly
cultivated, is the most difficult to reconnoitre well. Commence, as much as
possible, at the most elevated portions. Mark the commencement of the slopes;
examine the ravines, water -courses, roads, and pathways. See if it is necessary
to establish bridges, and if columns can follow the bottom of the valleys or the
crest of the hills. Inspect the streams, as is directed in Chap. XIV.; and
canals in the same way, giving the communications which they establish, a
description of the lockage, &c.
Give the position of springs and cisterns; the quality and
quantity of water, &c. The position, use, dimensions, construction, and
solidity of all bridges should be given; the approaches, and water -way; the
streets leading into towns and cities; the nature of the country in front of
them; the means of fortifying them; of destroying them; of re-establishing a
passage with the most advantage, regard being paid to the nature of the brooks,
the current, width, embankment, fords, and communications. Of ponds, marshes,
&c., mention whether they are formed from springs, from inundations, or
simply from wet ground; the best means of crossing them; at what seasons it is
practicable to pass them, and with what kind of troops, whether they are
unhealthy or covered with fogs. If there are causeways, state how they can be
repaired; if not, how they can be made, and how defended. Sound the depth of any
wagon -tracks. Prairies on which the grass is high and thick, or on which
patches of yellowish -green moss occur, should be carefully examined, for in
spite of their appearance, they are often impracticable even for infantry.
Examine the ground around them.
Take the depth, extent, and level to which the water can be
kept in inundations; the time required to raise the water to a given level; the
working of the sluices, the means of taking possession of, or defending them; of
opening or closing them.
On a coast, examine the shore, cliffs, rock, &c., which
may make an approach more or less dangerous or quite impossible; extended and
open portions, fit for making a landing; batteries and entrenchments established
to defend the anchorages, channels, and accessible points, or positions where
they may be placed in case of necessity. The adjacent islands which may be made
use of for advanced works; the rise and fall of the tides, which affect more or
less the approaches to the different points, and the variations which they
produce in the course of rivers; and the means of passing them; the low -water
marks; the creeks, bays, roadsteads, and ports; their advantages and
inconveniences; the size of vessels they are capable of receiving, and the winds
required to enter and leave them; the positions for camps, and the posts capable
of covering the principal establishments in the interior of the country. Notice
every thing characteristic of the accessible places; existing obstacles, and
those which can be added to defend the approaches to them. State the condition
of the forts, batteries, guards, and material. Analyze the system of defense
adopted, and propose modifications, if necessary. Estimate the force which can
be raised, in an emergency, either from the troops or the inhabitants, whilst
waiting for the arrival of the regular troops at the point of attack.
In reconnoitring a wood or forest, state its position,
extent, and thickness, as well as the height of the trees and undergrowth; the
gaps existing between masses of the trees; their width; whether the trees on the
right or left form a thicket, and whether they can be burned. The nature of the
soil, the surrounding ground, &c.; the communications, the means of
establishing, and their direction, in order that they shall not be taken in
flank; the means of forming abattis. Go around the forest, noting the roads,
streams, and ravines which lead to it, following them to their heads when not
too long.
The hind, quantity, &c., of heath, underwood, and hedge,
should be stated. Tall heath is usually practicable; low heath often marshy. Low
and thick hedges form a very good defense.
Roads are surveyed either by the compass or the eye, and
their direction noted, as also the width, whether variable or constant. State
whether railroads, paved or well -beaten, and if bordered by trees, hedges, or
ditches; distances between the principal places, the ascents
and descents, and estimate the time of marching them in hours; whether
constantly practicable, or so only
according to the weather and season. The country, streams, and towns along the
road; the roads which cross it, and where they lead. Heights which command them;
whether in curves or zigzags crossing mountains. How formed, whether by
excavation or embankment, and the length of the former; the dangerous points;
repairs necessary for the passage of artillery. The width of the track, more
especially in. sunken roads, which should be avoided as much as possible, or
filled up. An accident to a single carriage on such a road might stop a whole
column. If but a single road exists in one direction, see if it is possible to
open lateral ones for other columns. Trace the routes of these columns. Do not
neglect the pathways or unfrequented roads, reported by the country people as
impracticable, as they may often he repaired with little labor.
Examine passes, as to their being practicable for infantry,
cavalry, and wagons; the communications between them; and if connected by the
crests of the intervening hills; the means of guarding them; the time necessary
to reach the sunlit by the established roads; the possibility of opening new
routes.
In defiles, state the width and length of the gorge;
positions to be occupied to protect a orward movement or cover a retreat. The
nature of the ground at the entrance, and the troops which can be advantageously
employed there in battle.
In forts, castles, and citadels, give their position and
extent; their object, and the works connected with them. The protection which
they afford to a, city or the country. The obstacles or support offered by them
to an enemy. The nature and condition of the fortification; whether ancient or
modern, permanent or temporary; of great or small relief revetted, wholly or in
part; of masonry, brick, sod, or natural. The mines and galleries; surrounding
grounds; the defense capable of being sustained by the works themselves, and
those which may be added. The proper points of attack to be chosen.
For fortified cities, state their relation with each other,
and with reference to the movements of armies. The positions of the 1st, 2d,
lines, &c. Succors which they can give or receive. Means of directing these
succors according to the direction of attack. Resources in provisions, &c.,
and the means of collecting them. Facilities for establishing depots, hospitals,
&c. Nature and strength of the works, and of each front in detail. The
surrounding ground, and the advantages which it offers for attack or defense.
The positions to be occupied in the investment; communications to be established
between the different quarters, and the works necessary for the safety of the
lines.
With unfortified towns and villages, state the defense of
which they are susceptible; the inclosing walls, towers, ditches, dry, wet, or
full of water; the houses, whether against the walls or separated from them; the
number of the gates. The surrounding grounds; gardens; the roads and paths
adjacent to the place.
In reconnoitring any military position, three principal
objects are to be considered. 1st. The ground itself of the position. 2d. The
approaches to the place, and means of debouching from them. And 3d. The
communications, and the rear of the position.
A good position should be commanded neither on the front nor
on the flanks. Information to be collected in a catalogue. The names of cities,
towns, and villages; opposite, those of the hamlets which are dependent upon
them, with their distances from the chief places. Number of houses, united or
isolated. Population. The number of men and horses which can be quartered. The
quantity of grain, hay, straw, beeves, cows, calves, sheep, hogs, &c. The
mills, ovens, wells, and fountains. The means of transportation, wagons, boats,
horses, oxen, and mules. The number of farriers, wheelwrights, workmen in wood
and iron, tailors, shoemakers, saddlers, &c. The taxes, revenues, commerce,
and business of the places. The salubrity of the habitations, stables, air, and
water. The quantity of grain which can be ground, and of rations which can be
cooked in a given time. The combustibles. The iron, cloth, leather, wine,
brandy, &c.
On arriving before the place to be besieged, the siege -park
is established, as near as possible, to the point of attack, generally between
2,500 and 3,000 yards from the advanced works, taking advantage of the form of
the ground to cover it from the enemy's fire. The pieces are placed in the first
line, at four yards apart from axis to axis. In rear of them the platforms,
tools, and projectiles.
At 600 yards in rear of the park, the powder -magazines are
established, in a line, and about 200 yards apart, each containing from 25,000
to 50,000 lbs. of powder in barrels. The magazines are covered with oil -cloth
supported on a light framework. At 80 yards on the right and left of this line
parks are established to serve as arsenals for distributing the powder.
The workshops for the artificers are 200 yards in rear of
the magazines, and those where the fascines, &c., are made, 200 yards
farther to the rear. They should be as near as possible to forests. Parks for
the horses should be placed convenient to wood and water.
Batteries .- The points of attack are protected by a certain number of pieces
placed together in position, when they constitute a buttery, the term Fig.
271.being also applied to the constructions necessary for the use of one or
several pieces.
A battery consists of a covering mass ABCD, Fig. 271,
called a parapet, designed to protect the men and pieces, and of one or two
ditches to furnish the earth.
Sometimes the parapet is made of earth brought to the
position, and there is no ditch. The following are the usual dimensions of a
battery: KI, the thickness of the parapet, is 18 feet, in order to protect the
battery from pieces of large calibre. A T, the terreplein of the battery, is
ordinarily 26 feet wide, and has a slope of 1/60 for the purpose of shedding
water. B, the interior crest, is 7 ft. 6 in. high, and is so calculated that the
enemy's line of fire B X, shall pass 6 ft. 6 in. above the rear of the
terreplein. A B, the interior slope, has a base equal to two -sevenths of the
height I B. This slope is packed as hard as possible. C. the exterior crest, is
6 ft. high. B C, the top of the parapet, is given a slope to carry off the rain
-water which falls upon it. C D, the exterior slope, has an inclination a little
less than the natural slope of the earth, in order that the enemy's shot may not
crumble it down, thus decreasing the height of the parapet. DE, the berm, is
made from 2 feet to 4 feet wide, in order that the earth knocked down by the
enemy's shot shall not fall into the ditch, which would render the repairing of
the parapet more difficult. EFGH, is the ditch, the profile of which is
calculated in such a way as to furnish earth sufficient to form the parapet. It
is usually given a depth of five feet; but sometimes the presence of water or
rock renders it necessary to make it of less depth, and its width has then to be
correspondingly increased. The scarp E F, and counterscarp GH, are usually
sloped so that their bases are equal to half their height.
Sometimes it becomes necessary, in order to protect the men
and pieces from the flank fire of the enemy, to throw up epaulements, which join
on to the ends of the parapet making a small angle with its direction. For the
same purpose traverses are placed between the pieces. In consequence of the
obliquity of the epaulement to the enemy's fire, it need not be thicker than
twelve feet. The form is similar to that of the parapet, though the interior
slope need not be so steep.
Guns and howitzers fire through embrasures. These are called
direct, when the central line or line of fire is perpendicular to the
parapet, which is usually the case. When this line is oblique to the parapet,
the embrasure is said to be oblique.
The embrasure is laid out so that the base or sole is two
feet wide at the neck or rear part, and at a distance of five feet to the front
is increased to three feet.
The solid part of the upper portion of a battery, between
two embrasures, is called a merlon, and that part under the embrasures
which is solid throughout, is called the solid.
That part of the parapet included between the base of the
embrasure and the foot of the interior slope, is called the genouillère. Its
height, for a piece mounted on the siege carriage, is 3 ft. 6 in. The base of
the embrasure has a slope to the front, of ½ in. to 1 foot, to carry off the
water.
The sole of the embrasure is traced out as soon as the
parapet has been raised to that level, by laying as on the proper line of fire
five feet from the interior slope, and at that point, on a perpendicular line, 1
½ foot on each side. These two points and the sides of the neck are marlyed
with short stakes; and lines drawn through them on each side and produced to the
exterior slope, determine the splay of the cheeks of the embrasure.
In order to protect the cannoneers, the sides of the neck
are sloped only enough to make the width at the interior crest three feet. But
the slope of the cheeks is increased as they
approach the exterior slope, so as to give a fire to the
right and left, and prevent the cheeks from being blown away by the blast of the
gun.
As steeply-sloped earth does not stand well, some kind of
revetment has to be used. For this purpose, sod, arabians, saucissons, or hides,
are used.
The gabion is a cylindrical basket with no bottom,
three feet high and about two feet in diameter. They are set firmly in the
ground and filled with earth. They are preferable to saucissons on account of
requiring less wood, and being made and repaired more easily.
They are generally employed for the cheeks of embrasures,
for traverses, communications, &c., and are sometimes used in the same
revetment with saucissons.
The saucisson is a cylindrical bundle of foots, one
foot in diameter, and eighteen or twenty feet long, bound together with withes.
They are placed on top of each other with the proper slope, and seared to the
parapet with stakes and withes, or iron wire.
When hides are used to protect the cheeks of an embrasure,
it is generally in connection with some of the other revetting materials, and
they are securely staked down over them.
In a sandy soil, sand -bags are used as a revetment, as was
done at the attack on Vera Cruz; and in case of the scarcity of wood to make
gabions, &c., common barrels, filled with earth, serve very well. These were
made use of in the building of Fort Brown.
Common clay, mixed with chopped straw, makes a very good
revetment, when well packed in layers of. one foot thick.
When sand-bag revetments are used for the embrasures, the
cheeks and sole should be covered with a double thickness of wicker -world- to
protect the bags from the blast of the guns. The bags are made to break joints,
which is also the case with saucissons.
Sod revetments are seldom made use of in sieges, as it takes
very long to construct them. When the form of the ground permits it, the ditch
is made on the inside of the parapet, and is two and a half feet deep, and from
eighteen to twenty feet wide. The men and pieces are placed in the ditch; and
the parapet being formed in part of the solid ground, is more promptly made and
more solid. A small ditch is cut in this case at the bottom of the exterior
slope, to catch such of the enemy's shells as may roll along the ground.
Siege-pieces should always be accompanied with their
platforms, which are of especial importance with guns and howitzers, as these,
to fire accurately, require that the trunnions should be horizontal. Without the
platform, too, the ground would soon be worn into ruts, and in wet weather it
would be almost impossible to manoeuvre the guns.
The batteries are usually placed from twenty to twenty -five
yards in front of the parallels, to which they are joined by trenches.
Kind. - Batteries are called, 1st, according to the kind of piece used in
them; thus, gun, howitzer, and mortar batteries. Sometimes
they are mixed batteries, and contain pieces of different kinds.
2d, from the nature of the firing, as, direct, ricochet,
and breaching batteries, according as the pieces fire directly upon the
object, by ricochet, or for the purpose of making a breach; and
3d, from the direction of their fire. Thus, a direct battery
is one which fires in a direction perpendicular to the face of the work to be
struck, and the shot of which strikes the object without ricochet. An oblique
battery is one whose line of fire is oblique to the work fired at, the
firing being direct. A reverse battery strikes the interior of a face of
the work, and under a small angle. An enfilading battery strikes the
flank of a face, enfilading its length. Reverse
and enfilading batteries generally fire
ricochet shots. Ricochet and direct batteries dismount the
enemy's artillery, and destroy his defenses. Mortar batteries render the
communications between the different parts of the work; difficult, especially
for artillery; destroy the enemy's shelters, and set fire to or blow up the
magazines. Under the protection as these different batteries, the works of the
besiegers are pushed forward to the covered way, where the breaching batteries
are established to open the scarp wall. The breaching batteries cannot be
occupied until the fire of the work is almost silenced.
Gun and howitzer -batteries may occupy four different
positions in regard to the face attacked.
1st. They may be established in a position perpendicular to
the prolongation of the face to be destroyed, (1) and as the projectiles have to
pass over the face A C, Fig. 272, to fall upon the terreplein of A B, the pieces
should fire in ricochet and the battery is an enfilading ricochet -battery. This
is the best kind of a battery for dismounting the enemy's artillery. Usually,
the first piece fires along the interior crest, the second parallel to it. The
others are directed upon the middle of the adjoining face.
2d. If circumstances do not allow this position to be
occupied the battery (2) is placed within the prolongation of the face, so as to
strike the face on the interior, under a small angle. This battery fires in
ricochet, and is called a reverse ricochet battery. It becomes more effective as
its distance from the prolongation of the face is lessened.
3d. The battery (3), may be established on the other side of
the prolongation of the face, striking its exterior direct under a less angle
than 90ºIt then, by its oblique position, is not exposed to the fire from the
face, A B, and taking in flank the embrasures of the place, demolishes them more
easily. It is called an oblique battery.
4th. The locality sometimes renders it obligatory to make
the battery a direct one, firing without ricochets, which is the least
advantageous of all.
Tracing.- Batteries are laid out at night, the positions having been s
elected in the daytime As this is a duty on which artillery officers may be
ordered, although usually, in our service, performed by the engineers, the means
required and method of tracing will be laid down. In the French service, the
commanding officer of each battery traces his own.
With the assistance of some men, a dark lantern (to prevent
the position from being discovered by the enemy, and to see by), some stakes,
lines, and a measuring tape, two
rectangles are laid out; one representing the base of the
parapet, the other the upper opening of the ditch. These rectangles, if the
platforms are to rest upon the natural ground, and the earth taken from the
ditch in front, are placed about one yard apart to form the berm. But in case a sunken
battery is to be made, that is, one in which the platforms will be below the
natural level, and the earth for the parapet is taken from the rear of it, these
rectangles are only 18 ins. apart. This sunken battery enables the men to be
placed under cover sooner than the other; but it can only be employed when the
trenches and other works in its front do not intercept the fire of its pieces.
Seven is, usually, the largest number of pieces placed in
one battery, and generally not less than three. The number of guns being
established, the length of the rectangles to be laid out follows from allowing
18 feet for each gun, and six &et for each splinter -proof gabion traverse,
one of which is placed between every two guns when the battery is composed of
more than three.
The width of the rectangles for a battery on the surface is,
for the parapet, 26 feet; and for the ditch, about the same. For a sunken
battery, the parapet rectangle is 24 feet wide, and that for the ditch is 22.
The rectangles for the epaulements and their ditches are
laid out in the same way, allowing
from 20 to 30 feet for the length of the epaulement, and twelve feet, or more,
for its width, according to its obliquity to the line of the enemy's fire.
These rectangles, when laid out, are well marked with stakes
and cords.
Forming. - In throwing up the battery, two men per yard of the parapet are
allowed. They are placed one per yard in the ditch, one for every two yards on
the berm, and one for every two yards on the parapet. The last two throw the
earth toward the interior slope, and pack it. The men in the ditch are changed
every two hours, and the working party relieved every twelve. They work ten
hours, and rest two.
A man can throw earth with the shovel, thirteen feet
horizontally, or to a height of five feet.
When the excavation does not require the use of the pick, a
tasked man can shovel and load on a wheelbarrow frown 15 to 19 cubic yards of
earth per day. When thrown horizontally, more than six fleet, or lees than
thirteen, or to a height of four feet, or loaded on a, cart, the number of cubic
yards must be reduced to ten. An excavator by profession can remove with the
shovel, and load in a cart, as much as thirty cubic yards of earth.
The nature of the ground is expressed by adding the entire
or fractional number of pickers to the shovellers kept at work by them. Thus,
one shoveller and one picker, ground for two men; one shoveller and two pickers,
ground for three men; two shovellers and one picker, which is the same thing as
one shoveller and one half picker, ground for one man and one half.
In medium earth, one pick can keep two shovels at work; but
that these shall not interfere
with each other, they must be separated by a distance of
from five to six and a half feet. For excavations, the estimate is generally one
pick and two shovels for each space of from three to four yards long. The
relieving shovellers are spaced horizontally at four yards, and vertically at
about five feet. For each gang, one rammer and. one leveller are required.
In excavating ditches, banquettes are left at a distance of
five feet apart, and cut down so as not to interfere with the slopes. Those next
the counterscarp are cut away as the work progresses, and those next the scarp
when the parapet is about to be finished. The epaulement is formed of well
-rammed horizontal layers from eight to ten inches thick, the edges projecting a
little beyond the profile, and afterwards cut down with the proper slope.
Experiment proves that in siege -works, at the opening of
the trenches, a workman from the line, in seven night hours and in ordinary
ground will excavate about two cubic yards. In ten hours, this should be
increased to very nearly three cubic yards.
In the day time, as many men as possible are placed in the
ditch, and the rest employed in carrying forward supplies, and in other work.
Between twenty -four and thirty -six hours are required to form the battery,
axed only about half that time for a sunken battery.
The interior slope is revetted, Fig. 273, usually with
gabions, the proper slope being given to them by placing underneath, along the
foot of the slope, a row of fascines. When the first row of gabions has been
filled, and the earth of the parapet reaches the same height, a second her of
fascines and gabions is placed on top, and the work continued, the requisite
height being given either by placing soda on the top tier, or by earth alone.
Before the second her of gabions is placed in position, the
embrasures are laid out Their axes are eighteen feet apart, unless a traverse
intervenes, when the distance is twenty-four
feet, allowing six feet for the width of the bottom of the
traverse The sides of the sole are at an inclination of one tenth with the axis.
The top edges of the cheeks diverge more than the bottom. The cheeks are
revetted for some distance from the neck, either with gabions secured as already
described, the earth being compactly filled in around them; with fascines laid
on top of each other, sloped outwards, and secured with pickets and withes; with
sand-bags, which are laid in tiers, the layers breaking joints; or with s ods,
or hurdle-work.
The épaulements are not revetted, the interior slope being
made as steep as the earth will stand. Howitzer-embrasures are sometimes made
with a counter -slope, the sole receiving nearly the same inclination from the
sill upwards as the least angle of elevation under which the piece will be
required to fire.
Traverses .- The traverses, Fig. 274, are made only splinter proof, to
prevent the pieces of a bursting shell, for instance, from extending farther.
than among the cannoneers of
two pieces. They are not designed to resist shot, and
consist of only two tiers of gabions. The lower her is made of two rows inclined
towards each other at the top, filled and packed in between with earth. Two rows
of fascines are placed on top of these, and the second her of gabions on top of
them, inclined like the first, filled and heaped up with earth. The traverse is
from fifteen to eighteen feet long, and has an interval between it and the
parapet of two feet.
When traverses are used with sunken batteries, the distance
between guns separated by a traverse is increased to twenty -six feet. The
trench, Fig. 275, when first excavated, is sixteen feet wide at the bottom,
which is slightly inclined to the front, where the trench is three feet deep.
The front is nit down vertically in firm soil, and the rear receives a slope of
one-half.
As the trench will furnish only sufficient earth for the
parapet, that for the epaulement is obtained from a ditch five feet deep outside
of it, and that for the traverses from ditches nut outside the parapet and
opposite the position of each traverse.
The front of the trench is cut down nearly vertically, and
revetted with fascines, laid on top of each other, and pinned to the earth by
stakes passing through them and obliquely downward. By this means, the guns can
be run close up to the parapet, and their muzzles project well into the
embrasures, which are made of the some form and in the same positions as
prescribed for the other battery. When traverses are made in the sunken battery,
a portion of the ground, six feet wide, is left standing, and on this the
traverse is built. This kind of traverse is made by first laying down on top of
the ground left standing
two rows of fascines, five feet apart. On these two rows of
gabions, inclined so as to touch at the top, are placed, filled with earth as
before, and heaped up on top to the height of the interior crest. The sides of
the solid part of the traverse are cut to a suitable slope, arid revetted with
fascines. A passable of two feet is left between the interior slope and the
gabionade of the traverse.
Several holes should be dug at the most convenient points in
the trench of the battery, to collect the rain which may fall, and precautions
should be taken to prevent water from running into the trench, either from the
natural surface, or from the trenches leading to the battery.
In throwing up these batteries, a narrow ramp at the end of
each epaulement is left, leading from the natural level to the bottom of the
ditch, and serves for the convenience of the men whilst at work.
A trench of the ordinary dimensions (8 ft. wide at the
bottom, and 3.5, ft. deep one side, by 4 ft. the other), is made from each
extremity of the battery to the parallel in its rear, Fig. 276.
If the working parties are interrupted by sorties, the men
are withdrawn into the trenches, care being taken to make them carry their tools
with them, in order that the enemy may not make use of them in destroying the
work.
The powder-magazines should be at least 30 ft. in rear of
the parapet, with its ceiling not
more than a few includes above the natural level. The
interior height need not exceed 5 ft., which will be about the depth of the
excavation to be made. It should be 6 x 12 ft. in the clear, and the sides may
be formed of frames and sheeting -boards, or of a row of gabions crowned with
two courses of fascines. It is covered with splinter -proof timbers 6 x 9 in.,
over which is piled at least 3 ft. of earth, both on top and on the sides
towards the parapet and epaulements.
The door is placed in rear, and is reached by one or two
inclined trenches.
Mortar Batteries are of two kinds: those for mortars which throw shells, as
the 8 -in. and 10-in. siege; and those for the st one mortars. The coehorn
mortar being small, is placed in any unoccupied corner of the trenches. The
first kind are usually placed in front of the first and second parallel, and in
such positions as to bring as large a portion of the place under their fire as
possible. The stone -mortar batteries are used at shorter distances (in front of
the third parallel), to annoy the covered way and adjacent parts.
The platforms may be laid on the natural surface, in which
case the same form and dimensions are given to the parapet and epaulements as
those laid down for gun -batteries; but as the mortars have to be set back far
enough to enable the shell to clear the interior crest by about 3 ft., a
revetment is unnecessary, and the interior slope may be made as steep as the
earth will stand under firmly.
The front of the battery is estimated by allowing 15 ft;.
for each mortar, and 6 ft. for each splinter-proof traverse.
These batteries are, however, usually sunk beneath the
natural surface, since several feet difference of level in the position of a
mortar will have but little effect on the range. The trench is then made 13 ½
ft. wide at bottom; 3 ½ ft. deep in front, and 4 ft. in rear, with a reverse
slope of one -half. Height of parapet 4 ft.; thickness 18 ft.; berm 1 ft., and
the front slope of the trench with a base of 2 ft.
The labor of throwing up batteries is performed by line
soldiers. Eight artillerymen are assigned to each piece, and are relieved every
twenty -four hours. They level the terrepleins, revet the slopes, and form the
embrasures, in revetting which last, a mask is formed if necessary in front of
the month. It is made of two ranks of gabions filled with earth, surmounted by a
second rank filled with fascines, Fig. 277.
The platforms are laid whilst the battery is being finished.
For mortars and ricochet-batteries they are laid level, and for direct firing
have a counter -slope of seven or eight inches in order to diminish the recoil.
The hurter should be placed perpendicular to the directrix.
Mortar-batteries are usually made without embrasures, but
when, for the want of howitzers,
the mortars are to be fired in ricochet, embrasures are made for them with
genouilleres 3 ½ feet high, and an inclination of the sole of 9º. (Fig. 278.)
The platform in this case is given a counter –slope in order that the mortar
may fire under an angle sufficiently small, and to diminish the recoil.
Enfilading and counter batteries are usually armed with 18
pds. and 24 -pds., and 8-in.
howitzers. The fire of the guns is mainly directed to
destroy the enemy's artillery; that of the howitzers to sweep the covered ways
and ditches, to destroy the palisadings, and injure the traverses by exploding
shells in them.
All the batteries open their fire at the same time at a
given signal, so as to divide the attention of the enemy. Ricochet and mortar
-batteries fire night and day; direct batteries in the da ytime only.
Seven artillerymen are required for each gun; five for each
howitzer and 10 -in. mortar, and three for 8-in. mortars and stonemortars. A
portion of these maybe detailed frown the infantry. Each detail serves twenty
-four hours at a time.
Breaching -batteries .- Exposed revetments may be breached by heavy guns, at
ranges from 400 to 600 yards; and batteries for such guns are in all respects
the same as enfilading or counterbatteries. But when these revetments are
covered from distant fire by the crest of the covered way, the breaching
-batteries must be placed either on the glacis or on the terrepleins of the
defenses, at points where no obstructions interfere with firing the guns low
enough to form a breach practicable for the ascent of an assaulting column.
In either of these latter classes the batteries must be sunk
low enough to subserve the object in view. The embrasures are usually cut out of
the parapet, as an ordinary trench has generally to be first established, as a
preparatory step. The form and dimensions of other sunken batteries, with such
modifications as are demanded by the site of the battery, and the position of
the point to be attained, will apply in these cases.
Breaching-batteries, established either on the glacis or
terreplein of a work, will generally be exposed both on their flank and rear to
the fire of dangerous commanding points, from which it will be necessary to
cover them by traverses, the number and position of which will depend upon the
command and position of the dangerous points. To cover from the flank fire, if
the command of the dangerous point is considerable, it may be necessary to place
a traverse at each interval between the guns. The traverses used in such cases
receive a thickness of 14 ft., or seven gabions; their length depends upon the
relative positions of the dangerous points, and the exterior point of the
battery to be covered.
When the reverse of these batteries is exposed, it is
generally from the salient position of some comparatively distant point, from
which a slanting fire may be brought to bear on this part of the battery. In
this case it will generally be easy to cover the exposed part by running out
from the reverse of the battery, an end of a trench, to form a wing traverse
that shall intersect the lines of fire from the point upon every part exposed.
The guns of breaching -batteries should be placed so that
the direction of their fire may be as nearly perpendicular to the line of the
wall as possible; and when oblique, the anglo should not exceed 45º, otherwise
the effect of the shot will be greatly diminished, and the operation retarded.
Besides the breaching batteries, counter -batteries, in
every respect similar to the others, are established on the glacis. Their object
is to counter -batter and silence the artillery of the defense which may be
brought to bear on the breaching batteries, or on the passage of the ditches.
They are usually placed as the prolongation of the ditches.
The genonillere is equal in height three ranks of saucissons,
in order that the pieces may not tear away the revetment when they recoil. If
these batteries cannot be sunk, they are formed of bags of earth brought up to
the position. Breaching -batteries are armed with from two to six 24 or 32-pdrs.
In these batteries, the necks of the embrasures are closed
with a kind of oak shutter, bullet-proof, called embrasure -blinds, or mantlets,
to protect the cannoneers from the fire of small-arms.
At the siege of Sebastopol, the Russians constructed their
mantlets of several thicknesses of tightly twisted rope, securely bound
together, and hung like a curtain from the top of the embrasure, an aperture
being left in the lower part through which the muzzle of the gun was run. This
opening was made large enough to allow sufficient field of fire to the piece;
and the cannoneers were further protected by a circular mantlet made of the same
material, which fit closely on the chase of the gun, between the wheels, a small
opening on top being left for aiming through. These mantlets are perfectly
bullet -proof, and must have been of great service in protecting the Russian
gunners from the sharpshooters of their enemies in rifle-pits, &c. Various
obstacles may interfere with the construction of breaching batteries.
If the fire of the place is very deadly, or the nights very short. they must be thrown up from the interior. If it is impossible to sink them, the workmen must be covered by masks of stuffed gabions, earth, -mounds, &c. Should the earth be stony, it must be screened, and the stones placed at the bottom of the parapet, so that the shot may not strike them and injure the men. If a. battery has to be constructed on rock, or on marshy ground, the earth for the parapet must be carried to the position, or if possible the parapet be constructed of sand.-bags, the workmen being covered by masks.
Marshy ground is consolidated by laying down beds of
fascines, crossing each other at right angles, and fastened with hurdlework.
This is covered with earth mixed with straw. If a battery is made on the brow of
a hill, or other position where the width of terreplein is
limited, the rear of the platforms may be supported on
trestle -work. This kind of floor is formed of beams eight inches square, placed
about two feet apart. A counterhurter is fixed on it to prevent the piece from running as the platform
to the rear. The platform planks are nailed in their positions. The work is
protected by masks of gabions and fascines (Fig. 279), and these masks are
increased in number, in order to divide the attention and fire of the enemy.
Such a platform will not do to fire mortars from, the recoil being too directly
transmitted to the supports. In order to increase the angle of fire, a platform
broken into two steps is made use of. The lowest part, being in the rear,
receives the trail, whilst the wheels rest on the higher part in front. Fig. 280
a. This kind of a battery platform is resorted to when the piece will not give,
standing on its carriage in the ordinary way, an angle of fire sufficiently
great for the object in view. The angle of fire is diminished by the reverse
means, Fig. 280 b. Floating batteries may be constructed on inundated ground, by
making rafts, buoyed up with empty casks placed under them. A parapet is made in
front, of woolsacks, saucissons, or oak timbers. If the battery is commanded, it
becomes necessary to raise the parapet or lower the
terrepleins in such a manner that the enemy's shot will pass
6 ft. 9 in. above the rear of the platform. If it becomes .necessary to
establish a battery in a position very oblique, with regard to the object fired
at, it is made in offsets, and the pieces placed as it were in echelon, in order
to avoid oblique embrasures, which are objectionable.
One magazine should be provided for every two or three guns.
They are sometimes placed at the sides of the battery, and sometimes in the
parapet of the communications. For mortar and howitzer batteries small shelters
are also required for the purpose of loading hollow projectiles. They are formed
of a ditch 3 ft. wide, 3 ft. deep, and 6 ft. long, covered by a parapet and a
blindage of wood and saucissons covered with earth. The entrance is to the rear,
and approached by a ramp.
Defense.-- FORTIFICATIONS should be armed in proportion to their
importance and the military and other supplies which they contain. The pieces
should be of medium calibres, to enable them to be promptly withdrawn from the
fire of the besiegers, and replaced in more favorable positions. Some large
pieces, however, are indispensably
necessary to intimidate the enemy, and compel him to give
his works the usual dimensions. No
definite rule can be laid down as to the armament of a fortification, more
especially in regard to those in this country. Generally speaking, 18 and 24 -pdrs.
are large enough for any interior forts; whilst those on the sea -coast, where
most of ours are situated, should be well provided with guns, howitzers, and
mortars of the largest calibers, in order to cover the largest field of fire
effectually, and prevent the approach of vessels of all kinds. They must,
besides, possess a proportion of smaller calibres, including some field pieces
for the land fronts, and to be used in interrupting the landing of troops.
The maximum amount of ammunition is 1,000 rounds per gun,
800 per howitzer, 500 for 10-inch mortars, and 700 for 8 -inch; 2,000 rampart,
and 5,000 hand grenades; and the minimum, three -fifths of this.
The artillery officers in a fort, and more especially the
chief one, should be perfectly acquainted with all parts of the work, and all
the adjacent ground within the sphere of attack, as on these will depend the
proper disposition of the pieces; They should also have marks on the surrounding
ground, so as to be able to estimate correctly the distances of the worlds and
batteries of the besiegers. There should be at least one skilful gunner for
the service of each piece, and as only
one-third of the garrison are generally under arms at a
time, there should be three times as many of these gunners as there are pieces
in the place, including the reserve pieces. Three auxiliaries for each piece of
small calibre, and four for the large, may be taken from the infantry. The
workmen and artificers should number nearly one -fifteenth of the gunners.
In case of necessity, the services of citizens to assist in working the
guns, may be made use of, or they may be employed as workmen and artificers.
Besides the battery -horses used in making sorties, a
certain number are necessary to transport the pieces from place to place.
When the place is about to be attacked, the bastions are
each armed with three pieces, placed in barbette; one 8 -inch howitzer in the
capital, and one 18 -pdr. on each face. The flanks are often armed with field
guns to fire through the embrasures at reconnaissances and workmen. The front of
attack is lighted up with pitched fascines, rampart-posts filled with
composition, or with tar -barrels and fire -balls thrown forward towards the
enemy.
The enemy should be closely watched, in order to ascertain
the moment when ho opens his trenches. For this purpose, the garrison should be
in communication with persons outside, if possible, so as not to be taken by
surprise. Some field -pieces should then be run out in front of the glacis, the
enemy's position lighted up with fire -balls, and grape -shot fired upon his
workmen for two or three hours; after which, the enemy having' sheltered himself
from such projectiles, shot and shell are used, the latter with but little
velocity, so that they may ricochet along the ground and enter the trenches.
So soon as the point of attack is satisfactorily determined,
all the disposable artillery is placed in the most favorable positions for
sweeping the ground in front. For this purpose,
one 8-in. howitzer, firing along the capital, and five 18 or
24 -pdrs. on each face, are placed in the bastion of attack. Seven or nine
pieces of like calibre, and similarly disposed, may be placed in the cavalier of
the bastion.
Eleven pieces are placed in each demi -lune of the attack,
one, an 8 -in. howitzer, firing along the capital, the others 12 or 18 -pdrs.
Six on the face, bearing on the ground opposite the bastion of attack, the other
three on the other face.
Five pieces of large calibre on the faces of the two
collateral bastions which bear most directly on the trenches; and their flanks
which bear on the bastion of attack, should each receive four pieces near the
angle of the curtain.
In the collateral demi-lunes, six pieces are placed on the
faces that bear on the trenches. Sixteen 8-in. howitzers should be placed in the
covered ways of the point of attack, and of the two collateral fronts; two being
in each place of arms to fire in ricochet along the capitals. About twenty
mortars should be distributed along the curtains and in the demi-lune redoubts.
The pieces on the faces which are enfiladed should be
covered by gabionade traverses, one between every pair. The barbettes in the
salients will be partly cut down, and the parapet raised to form embrasures for
the guns. The traverses are 22 feet long, 9 feet high, and 12 feet thick at the
base by 8 feet at top, and are revetted with gabions. The pieces enumerated form
a medium armament for the point of attack at this period of the defense; and
whilst they are being placed in position, embrasures, platforms, and traverses
are prepared at suitable positions, to place the artillery under shelter as soon
as the enemy shall have established his enfilading batteries.
A continuous fire should be kept up on the parts of the
trenches in progress, particularly when the enfilading batteries are commenced.
The fire, instead of being scattered over all the batteries, should be
concentrated on a few of the principal ones, as by delaying these, the others,
if the besiegers act prudently, will not open their fire until all are ready.
As soon as the enfilading batteries begin to produce a
marked effect, half the pieces on the faces of the defenses are withdrawn and
held in reserve, those being retained in position which are best protected by
the traverses, and keep up a steady fire on the heads of the
approaches as they are advanced, redoubling the ricochet firing whenever
the workmen and guard of the
trenches are relieved.
After the third parallel is constructed, the howitzers may
be advantageously replaced by
stone and coehorn mortars firing from the covered ways, and
the redoubts of the re –entering places of arms. Guns will be placed in
embrasures to fire in the direction of the ditches of the demi-lunes of attack
again st the crowning of their covered ways.
The defense at this time should be more than ever energetic.
The converging and close fire of the artillery, combined with that of small
-arms, is capable of retarding very much the progress of the besiegers. Their
works should now be well lit up at night with fire -balls, to prevent their
rapid advancement under cover of the darkness. The embrasures should be
protected with bulletproof shutters, or masks. Blinds, or covers of
timber, fascines and earth, under which guns can be secured from projectiles
which would reach them at top or in Rank, will now be very serviceable; but they
must not be exposed to the direct fire of the enemy, and should allow free
escape to the smoke, without which they would prove untenable. A few guns
covered in this way, and placed in the salients of the collateral works, to take
in reverse the trenches constructed on the glacis, will greatly retard the
progress of the sappers.
As soon as the besiegers have arrived at within thirty yards
of the covered way, hand-grenades are thrown into their works, stone -mortars
are gathered in the adjacent portions of the work and the establishment of the
breaching -batteries retarded by a well-sustained fire of shot, shells,
grenades, &c. The pieces are now withdrawn into the redoubts of the work
abreast of the besiegers. The demi-lune redoubts receive five guns in the
salient and four on the flank looking towards the bastion of attack. The
redoubts themselves are not disarmed until the last extremity, when the pieces
are, if possible, withdrawn into the body of the place.
As the moment for crowning the covered way approaches, the
efforts of the besiegers to retard the works of attack will be redoubled. In
addition to the measures already laid down, the flanks which bear on the point
of attack will be armed with artillery; and oblique embrasures will be
constructed in the curtains, to sweep the positions along the bastion-covered
ways, where the besiegers are making the breaching and counter batteries.
The different breaches are defended with grape, hand and
rampart grenades, powder -bags, &c. Small mines, or bombfougasses, should be
prepared at the summit of the breach, to be exploded as soon as the besiegers
gain possession of it. The top of the breach is strewed with every possible
obstacle that can retard the progress of the storming party; and grenades,
thundering barrels, &c., will be rolled down on the troops as they ascend
the slope. Coehorn -mortars and field -howitzers, loaded with grape, are placed
in position, ready to fire upon the enemy as soon as lie reaches the top.
Sea-coast Defenses .-- Artillery plays the most important part in sea -coast
defenses; more especially now that the calibre has been so much increased, as by
a single well -directed shot to endanger the safety of ships of the largest
class. The fixed position of the land -battery, and the small surface which it
presents, give it an immense advantage over vessels. It may be laid down as a
principle, that a land -battery of four pieces is capable of contending
advantageously with a ship of 120.
Sea-coast batteries are usually established near the
entrances of ports, or at other points on the coast, for the defense of road
steads, anchorages, small commercial ports, &c. They should be as far
advanced as possible, as on islands, projecting points, &c., in order to
maintain command over as great a distance as possible. A relief of from 30 to 45
ft . protects them from the ricochet fire of ships, whilst it gives the pieces
the power of using that fire on the water up to 1,500 yards.
Shot loses but little of its force by ricochetting over
calm, still water. One of large calibre, which has ricochetted at 1,200 yards,
has still sufficient force to penetrate the side of the largest sized vessel. If
the ground between the battery and the sea presents a slope
favorable for the ricochet fire of an enemy, it should be cut into
terraces, the rises of which will catch the shot.
The distance of the anchorage is determined by the depth of
water at different points of the coast. The largest class of vessels require
from 25 to 30 ft.; frigates, from 19 to 23 ft.; and sloops of war, from 16 to
18. It is, therefore, easy to ascertain the distance of an anchorage from a
battery according to the kind of vessel.
The parapet of these batteries should be of earth, or at
least covered with it to a depth of two feet. It is about 18 ft. thick, and 7
ft. 6 in. high. It is frequently revetted on the interior with masonry to a
height of about 4 ft. 2 in. The width of the terreplein is 18 ft. When subject
to enfilade from the fire of shipping, returns are made at the extremities, and
traverses placed at intervals. The ditch should be as deep as possible.
The distance between guns and howitzers is from 18 to 21
ft., and the height of the interior crest, above the platforms, about five feet,
so that the pieces may fire over the parapet and follow vessels under way. The
field of Ere of each piece is 90º, or 45ºon each side of the directrix, so
that if a vessel passes a battery at a distance of 300 yards, it is under the
fire of a piece for at least a distance of 600.
The armament of sea -coast batteries varies with their
importance. The largest are armed with the largest guns, 32 and 42 pdr.
columbiads (now 64 and 128 -pdrs.), and sea –coast howitzers. Some field
-howitzers are sometimes also included. A certain quantity of light artillery
(especially howitzers), is also necessary to accompany troops which may be
detached to prevent an, enemy from disembarking. But few pieces are kept mounted
in our sea-coast defenses; and in case of a threatened war, this would be the
first measure to be attended to.
In time of war a sentinel is posted night and day on these
batteries, to give the earliest intelligence of the appearance of an enemy.
Everything should then be prepared; charges, projectiles, &c. The platforms
should be swept clean, and it should be ascertained
beforehand that the chassis move freely on the traverse
circles. The pieces are fired at the water-line of the vessels. If the shot
falls short it will reach the vessel by ricochets; and the chances for producing
a good. effect are greater than when firing higher.
Hot shot may be most advantageously employed against vessels
at anchor, and for combats of a certain duration, which allow time enough to
heat the shot to the necessary degree, and the requisite careful and deliberate
aiming.
Sea-coast batteries are provided with furnaces or grates for
heating shot. One hour is required to set one of these furnaces going, but after
that only from 30 to 35 minutes to heat a 32 or 42-pd. to a cherry red.
A cold shot makes, in the side of a vessel, simply a hole,
which closes up in part by the elasticity of the wood, and is easily stopped
with a large plug.
The use of shells with sea -coast artillery permits rapid
firing, and enables us to seize the favorable occasions when the most injury can
be inflicted on the enemy.
The fire of heavy 8 and 10 -in. shell-guns is almost as
accurate as that of guns, and takes effect at from 3,000 to 5,000 yards; but the
most efficient range is from 1,700 to 1,900 yards.
10-inch mortars give ranges of over 4,000 yards, and are
employed against distant anchorages. Their fire, although very uncertain, is of
great moral effect, in the defense of sea-coasts, from the knowledge of the
great havoc sometimes produced. If the proximity of an anchorage enables an
enemy to man his tops, and obtain a plunging fire into the battery defending it,
field -pieces are established in the rear to fire upon the netting of the tops.
Rockets and other incendiary fireworks would be fired against the
sails and rigging to set them on fire.
Firing from ships is very uncertain, on account of the
movement. As the range is shortened, the fire improves; but the ship being
thereby brought within shorter range of the guns and howitzers of the battery,
the contest becomes more than ever unequal. The bombardment, by the French, of
the castle of St. Juan d'Ulloa, took place at 2,000 yards. Of 302 shells fired,
six only fell in the fort, whilst some went 1,200 yards beyond.
In estimating the quantity of artillery necessary for the
armament of a permanent fortification, considerable discrepancy of opinion
exists among military writers. A resolute garrison might preserve a work of
tolerable strength from a coup de main without the aid of cannon; and an
idea of the maximum amount of artillery might be arrived at, by supposing each
front armed with as many pieces as it can carry, with a suitable number of
pieces in reserve to provide for casualties. But these are inadmissible
extremes; and a medium estimate is to allow three heavy guns, and one heavy
mortar, for each bastion or front, with
sixty heavy guns, twenty heavy mortars, and ten stone or light mortars for the
armament of the point of attack. An estimate of the allowance of ammunition is
made by allowing 1,000 rounds for each gun, 800 for each mortar, 100 musket
cartridges per day for each soldier on guard, and 300 lbs. of powder for each
mine.
In estimating the quantity of artillery necessary for the
besiegers, the quantity employed by the besieged is taken as a basis, and as
many guns and mortars allowed for the enfilading, counter, and mortar -batteries
as, is presumed, form the armament of the point of attack, with the addition of
forty or fifty heavy guns for the breaching batteries. The medium allowance of
ammunition for the artillery is 1,000 rounds for each gun, and 800 for each
heavy mortar.
These estimates are of a very general character; and are
introduced merely to give some idea of the relative proportions in question.
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