THE DEFENCE.
=99.= =Preliminary Considerations.=--The defence of a
fortified place is entrusted to a commanding officer, who, when the
siege is established, is generally known as the “Governor of the
Place.” His duties become more exacting and his powers more absolute
from the beginning of hostilities until the place is invested and
cut off from communication with the exterior, when, since the whole
responsibility of the defence rests upon him, his powers over
both the garrison and the inhabitants of the place, of necessity
become autocratic in all matters affecting the defence, directly or
indirectly. He, of course, avails himself of the counsel and advice of
his subordinate officers and may make up a “Council of Defence” from
his second in command and the commander of the engineers and of the
artillery; but the ultimate decision of all questions must rest with
him alone.
During peace and after the beginning of hostilities up to the near
approach of the investing force, the civil authorities retain their
ordinary jurisdiction, unless martial law is declared by proper
authority; but after the place is invested, martial law (or state of
siege) exists from necessity, and the police power, the control of
provisions and supplies of all kinds, public and private, buildings,
animals, vehicles, etc., and everything necessary for the defence of
the place fall into the hands of the governor, who also is empowered
to direct who shall be sent out and who shall be retained within the
place, and what necessary service or labor shall be performed by the
inhabitants. Having been selected for these onerous and exacting
duties, he, under no circumstances, allows himself to be cut off
from his post, and is therefore debarred from leading his troops in
person in the active operations outside the work or exposing himself
unnecessarily or recklessly during any period of the siege.
=100.= =The Garrison.=--The garrison should consist of
artillery and infantry, and, in an intrenched camp, of enough mounted
troops for escort, messenger, and a limited vedette service.
The strength of the infantry is generally regulated so as to give a
suitable garrison to each detached work, and about 1½ to 2 men for each
yard of the front of attack. The artillery is allowed about 12 men for
each gun. The number of engineers is determined for each place by the
probable amount of engineer work that will be required. These troops
make up about one-third of the entire force.
A general reserve of all arms (principally, however, foot troops)
makes up the other two-thirds, and is held as “a fighting force”
for preventing the investment of the place, or for breaking up the
investing lines when established. This reserve is called upon for
work on the front of attack or in the trenches only when it cannot be
avoided.
In smaller places the portion of the garrison called upon for the
outer line of defence may be increased to one-half or two-thirds, and
the general reserve be reduced to one-half or one-third of the entire
force. When the investment is strongly established the general reserve
will usually be combined with the other troops.
The troops engaged on the front of attack are usually assigned to the
different sectors of attack and are divided into reliefs (ordinarily
three), each relief having as a rule a tour of one day in the front
lines, one in the immediate supports, and one in the reserve and
in interior fatigue duty. The Governor, however, so regulates the
details as to impose upon the troops the least work consistent with an
energetic defence.
=101.= =Armament.=--The guns for arming the place should be
placed in position or in store within the works before the beginning
of hostilities. There should be mounted in commanding positions a
sufficient number of high-power guns to hold the enemy’s first works
at a distance and to fire upon his camps, etc., if placed too near.
In addition to these, a full supply of light guns, including machine
and rapid-fire guns, should be at all times equipped and supplied for
immediate use in meeting an assault or surprise. Their emplacements,
platforms, etc., should be in readiness for use at any moment.
In large places and for an active defence there will be needed also
enough field-guns to properly equip the general reserve (about 4 guns
per 1000 men). These should be considered a part of the equipment of
the reserve.
It being, from economical considerations, impossible to supply guns to
fully arm all the fronts of a place, enough only are usually provided
to thoroughly equip the sector of attack and to replace those disabled.
These are stored within the place where they are secure against
deterioration or injury, and are mounted in the sector of attack
when it is definitely determined. The numbers of high-powered guns,
howitzers, mortars, and machine and rapid-fire guns needed must be
determined from the size of the place, its garrison, and the character
of attack which may be expected.
=102.= =Ammunition, Provisions and Supplies.=--A plentiful
supply of ammunition, especially of projectiles, for all the guns
should be kept constantly on hand. The projectiles, which may be stored
for an indefinite term without deterioration, may be distributed in
magazines in proximity to their batteries; the powder should be so
stored as to preserve its properties, and be distributed to the service
magazines at such times and in such quantities as may be necessary.
Other equipments will be stored and handled in accordance with the same
principles.
The utmost care will be taken in storing and issuing the provisions and
supplies belonging to the troops; and in cases of necessity during the
siege the sales of provisions to the inhabitants by the dealers will be
regulated, both in prices and quantities, by the military governor.
=103.= =Sanitation and Hygiene.=--The most rigid sanitary
measures and rules of hygiene should be enforced from the beginning of
the siege, under the direction of the military governor, whose medical
officers should join with the health officers of the place (if any
exist) in guarding not only the troops but all the inhabitants from all
avoidable causes of epidemic diseases. Extreme rigor in carrying out
these regulations in not only allowable, but is most urgently required.
=104.= =Preparations for Defence.=--An active defence
being presupposed, all possible measures for its execution should be
taken before the near approach of the enemy interferes with them. The
principal ones are as follows, viz.: Advanced posts are established
as far from the work as is prudent, say 3500 to 4000 yards, placed at
points which may be easily defended or which would be advantageous
positions for the enemy’s batteries, etc. These, when possible, should
be so placed that the ground between them is swept by their infantry
fire and by the artillery of the place. They should be provided with
good cover for the troops, and parapets for infantry and field-guns.
When not naturally strong, field-works should be built. Quarries,
ditches, sunken roads, villages, woods, etc., should be taken advantage
of, either as points of defence, passive obstacles, or covers for
communications, as may be best. Lines of retreat to the work as
secure as possible from hostile fire should be provided. All supplies
in the vicinity of the work which will be useful during the siege
should be collected and taken into the place. Means of communicating
with the exterior by telegraph, telephone, signal flags, lanterns
and heliotropes, carrier-pigeons and balloons, should be secured.
Search-lights for illuminating the exterior should be obtained, and
as soon as practicable bomb-proofs and shelters for the inhabitants
should be prepared in the body of the place; and in connection with the
civil authorities the fire department of the place should be organized
and taught how to extinguish fires with dry earth and by pulling down
buildings when water is not available.
The service of security and information should be extended to the
furthest possible limit, not only by outposts, etc., but by telegraph
operators and reliable correspondents at long distances from the place;
and preparations should be made to retard the approach of the enemy by
the destruction of the roads, bridges, etc.
=105.= =Defence during the First Period of the Siege.=--Upon
the approach of the enemy each work should receive its permanent
garrison, and the fighting reserve should go out to occupy the advanced
posts and to take full advantage of its interior lines to hold him back
and punish any careless or ill-advised advance, being aided in this
when possible by the fire of the heavy guns of the place. Care must
be taken to avoid too great dispersion of the troops, and exposing
advanced parties to being cut off and captured by pushing them too far
to the front or holding their positions too long; but no opportunity
should be missed of attacking and destroying or beating back hostile
detachments when tactical conditions warrant it.
The defence during the first part of this period differs but little
from the ordinary defence of an intrenched battle-field. The principal
differences arise from the fact that the flanks of the advanced lines
and the lines of retreat to the work are so well covered that with
ordinary precautions they may be considered secure, and all energies
may be directed to meeting the front attack and executing offensive
returns. So soon as the point of attack selected by the enemy becomes
known the advanced positions may be more fully manned and equipped;
trenches with inconspicuous parapets, or preferably without any, may
be made to cover the infantry, field-guns, and sometimes siege-guns on
travelling carriages. These positions may be, as previously stated,
2500 to 3000 yards from the permanent works, and the intervals between
them may be swept by the heavy guns of the latter.
If these positions can be so strongly held as to compel the besieger
to attack them with his heavy guns, he will be compelled to establish
his first artillery position at a very great distance--possibly 5000
to 6000 yards from the work. [At Belfort, 1870, positions of this kind
were taken only after seventy-seven days of siege.]
As the advanced positions may be subject to the fire of the heaviest
class of siege-guns, if any parapet is made it should be of the nature
of a glacis of gentle slope and little command. Infantry trenches
should be made narrow and deep as a protection against shells and
shrapnel (Pl. IX, Fig. 84), and gun-emplacements should be as small as
practicable and almost entirely in excavation, for the same reason.
Positions so prepared suffer very little from gun-fire, and will
frequently require attack by systematic approaches.
An efficient outpost service must be maintained in front of these
positions to prevent their being taken by surprise.
When but a limited number of troops are available for defence it is
of course impossible to push out the advanced posts so far to the
front. In all cases, however, they should be placed at the greatest
practicable distance.
=106.= =Opening of Artillery-fire by the Defence.=--The
artillery-fire of the defence should be opened upon the besieger’s
batteries, etc., before they are ready for action, so that the ranges
may be obtained and the tables of fire corrected without interference
by the hostile fire. If this can be accomplished, the increased effect
due to the accurate fire of the defence may more than counterbalance
the numerical superiority of the attack, and result in preventing the
completion of some of his batteries and in silencing others.
If, on the other hand, the attack anticipates the defence in obtaining
the range, his superiority in numbers and accuracy will frequently
necessitate abandoning some emplacements and mounting the guns in
others, where they may be used in the later stages of the siege.
=107.= =Defence during the Bombardment and Assault.=--The
amount of ammunition which can be profitably expended by the defence
during the bombardment must be determined by the quantity on hand and
the advisability of exposing by their fire the positions of the guns.
The infantry troops and the light guns are held under cover, ready to
be moved forward to meet the assault if made. Special care will be
taken to avoid being deceived by false attacks; and the assault, if
made, will be met as previously described (par. 6).
If the attack is repulsed, an offensive return may be made by the
general reserve, assisted, when necessary, by the local reserves of
the front of attack; but the garrisons of the permanent works should
not be withdrawn from them for this purpose, as it is always possible
that they may be needed to protect the works and cover a retreat. If
the assault succeeds, the defenders will retire to their positions in
rear, from which the strongest possible fire will be directed upon the
pursuing troops and upon the captured position to render its possession
difficult or impossible. If the assailants are driven off, the position
is immediately reoccupied by the defence.
=108.= =Defence during the Second Period of the Siege.=--The
point of attack having been definitely determined by the preliminary
steps of the attack in opening the parallels and establishing the
batteries, the besieged will at once proceed to mount extra guns
and reinforce the troops upon the threatened fronts. He will keep
his outposts or sentinels during this and the subsequent periods as
far to the front as possible, to prevent surprises and to keep out
reconnoitring parties spies, etc., etc.
From observations previously established, he will locate at the
earliest possible moment the batteries, etc., of the attack, and will
prevent their completion and arming by the use of shells and case-shot
charged with high explosives, fired from howitzers and mortars. He will
use his long guns for counter-battering those of the besieger, and
generally for direct fire upon exposed targets.
By taking the initiative he may frequently obtain the upper hand in
the artillery duel, and possibly be able to prepare the way for strong
sorties, and the destruction of the besieger’s works. In any case he
must at this stage develop the full fire of his guns and work them to
their maximum value.
If, however, the superiority of the artillery of the attack is
pronounced, and it becomes impracticable to serve any battery
advantageously, it will be better to dismount its guns and remount them
in other positions, as indicated in the preceding paragraph (par. 106).
All efforts will be made to prevent the construction of the parallels
and approaches, their positions being discovered by the use of the
search and other lights, and the work upon them retarded by direct and
curved fire. For the latter light rifled mortars promise to be very
effective.[7]
The trenches connecting the detached and intermediate works will be
strengthened, and counter-approaches will when practicable be driven
out to afford positions for enfilading the approaches. The field and
machine guns will be held in constant readiness for use, and will
be brought into action at every favorable opportunity; but will be
withdrawn and placed under cover previously prepared so soon as the
fire upon them becomes too severe to be endured.
Meanwhile a new position in rear, with its flanks supported upon the
adjacent detached works, will be selected and made ready for defence in
case the front line is taken.
The general reserve will be used for offensive movements, which are
made whenever favorable opportunities arise, particularly in making
counter-attacks after unsuccessful assaults.
=109.= =Defence during the Third Period.=--The defence of
the detached works of an intrenched camp during the Third Period will
be conducted, so far as the general reserve is concerned, in very much
the same manner as during the Second Period; but in the immediate
defence of the detached work itself, owing to the close approach of the
besieger, its character will change. The artillery except the field
and machine guns will be silenced, and the latter will usually be
only available for defending the ditches and for repelling assaults.
Light guns will, however, be held in readiness for temporary use when
practicable.
The outposts will of necessity be drawn in and replaced by a chain of
sentinels along the parapets of the covered way or the main parapet,
who will pick off the besiegers at every possible chance, and will be
reinforced by the rest of the garrison when an assault is imminent.
All flanking defences will be kept in as good condition as possible,
and in readiness to prevent the crossing of the ditch, or to repulse
an assault. Grenades and shells will be kept in readiness to roll into
the ditch, the breaches will be obstructed and mined if practicable,
counter-mines will be brought into play, and all other possible
measures taken to retard the approach of the besieger to the breach
and to repel his assaults. When, however, the work is reduced to such
a state as to make its defence hopeless, it should not be held at the
expense of great losses to the defence, unless the besieger’s works can
be considerably delayed by doing so. When the position consists of an
enceinte with ordinary outworks, the investment during the Third Period
of the siege will be closer, the opportunities for using the general
reserve will usually disappear, and its troops will be merged with
those of the general defence.
When, in this case, the place is to be defended to the last, all
measures will be taken for the defence of the breach; and after this is
carried, for the final defence of the inner retrenchments or keeps.
The tactical handling of the garrison for this purpose is in accordance
with the principles already laid down (par. 6, and Art of War, pars.
282-84.)
The sorties recommended during a siege are, when made by the general
reserve and in large bodies, usually carried out by moving the troops
from the collateral works upon the flanks of the besieger’s works. In
the close attack, however, they may be made by small parties moving
to the front from the nearest outpost or salient. The object in all
cases is the same--to destroy the enemy’s works, delay his advance, and
inflict upon him all possible loss.
THE CAPITULATION.
=110.= Should the defensive policy of the state not require a
place to be held to extremity, the governor must be fully informed
of the fact, and the extent of the defence and the conditions of
capitulation must be fully understood by him before the investment.
As a rule, however, no excuse will be received for the surrender of a
place until every means of defence is exhausted, and further resistance
is not only hopeless, but impossible, the only rule which can guide
the governor being that “one additional day of defence may be of
incalculable benefit to his country.” The old rule, copied from the
French, but no longer observed by them, requires the defence to sustain
at least one assault on a practicable breach in the body of the place.
Within recent years, in civilized warfare, no cases have occurred in
which such assaults have been made, the places having been reduced by
the more distant attack; but assuming such an assault to be repulsed,
it will not justify the surrender of the place so long as a possibility
of repulsing similar assaults exists. The garrison must withstand all
attacks of whatever nature to the last extremity, and continue the
defence up to the full requirements of duty and honor--surrendering
only when nothing else is possible.
JOURNAL OF THE DEFENCE.
=111.= =A Journal of the Defence=, entirely similar to
that of the attack, will be kept by the besieged for use by the War
Department in case of a successful defence. Nothing should be entered
in the journal which might be of special value to the besieger in case
the place is taken, but a separate journal of such matter should be
kept in cipher, or should be destroyed before the surrender of the
place.