Chapter XIII: Part 13

The command and obstacle were as necessary in the days of smooth-bore muskets and guns as in those of javelins and arrows. When the enemy could get close up to a work without serious loss, and attack in close order, the defenders needed a really good obstacle in front of them. Moreover, since they could not rely on their fire alone to repulse the attack, they needed a two-deep line, with reserves close at hand, to meet it with the "arme blanche." For this purpose a parapet 7 or 8 ft. high, with a steep slope, perhaps palisaded, up which the attackers must climb after passing the obstacle, was excellent. The defenders after firing their last volley could use their bayonets from the top of the parapet with the advantage of position. The high parapet had also the advantage that the attackers could not tell what was going on inside the redoubt, and the defenders were sheltered from their fire as well from view until the last moment.

The strength of a fortified line in the 18th century depended principally on its redoubts. Lines of shelter trenches had little power of defence at the time, unless they held practically as many men as would have sufficed to fight in the open. Obstacles on the other hand had a greater value, against the inelastic tactics of the time, than they have now. A good position therefore was one which offered good fire-positions for redoubts and plenty of facilities for creating obstacles. Strong redoubts which could resist determined assaults; good obstacles in the intervals, guns in the redoubts to sweep the intervals, and troops in formed bodies kept in reserve for counter-strokes--these were the essentials in the days of the smooth-bore.

The redoubts were liable to a heavy cannonade by field-guns before the attack. To withstand this, the parapets had to be made of a suitable thickness--from 4 or 5 ft. upwards--according to the time available, the resisting nature of the soil, and the severity of the bombardment expected.

The whole of the earth for the parapet was as a rule obtained from the ditch, in order to make as much as possible of this obstacle. The garrison in all parts of the interior of the redoubt were to be sheltered, if possible, from the enemy's fire, and with this object great pains were bestowed on the principle of "defilade." The object of defilade, which was a great fetish in theoretical works, was so to arrange the height of the parapet with reference to the terreplein of a work that a straight line (not, be it observed, the trajectory of the projectiles) passing from the muzzle of a musket or gun on the most commanding point of the enemy's position, over the crest of the parapet, should just clear the head of a defender standing in any part of the work. This problem of defilade became quite out of date after the development of time shrapnel, but was nevertheless taught with great rigour till within the last twenty years.

The sectional area of the ditch was calculated so that with an addition of about 10% for expansion it would equal that of the parapet. If a wider and deeper ditch was considered necessary, the surplus earth could be used to form a glacis.

The interior of the redoubt had to afford sufficient space to allow the garrison to sleep in it, which was sometimes a matter of some difficulty if a small irregularly shaped work had to contain a strong garrison. Consideration of the plan and sections of these works will show that the banquette for infantry with its slopes, and the gun platforms, took off a good deal from the interior space within the crest-line. Guns were usually placed at the salients, where they could get the widest field of fire. They were sometimes placed on the ground level, firing through embrasures in the parapet, and sometimes on platforms so as to fire over the parapet (_en barbette_).

As in permanent fortification, immense pains were taken to elaborate theoretically the traces of works. A distinction was made between forts and redoubts, the former being those which were arranged to flank their own ditches, while the redoubts did not. Redoubts again were classed as "closed," those which had an equally strong defence all round; and "half-closed," those which had only a slight parapet or timber stockade for the gorge or rear faces. Open works (those which had no gorge defence) were named according to their trace, as _redans_ and _lunettes_. A redan is a work with two faces making a salient angle. It was frequently used in connexion with straight lines of trench or breastwork. A lunette is a work with two faces, usually forming an obtuse angle, and two flanks.

The forts described in the text-books, as might be expected, were designed with great ingenuity, with bastioned or demi-bastioned fronts, star traces, and so forth, and in the same books intricate calculations were entered into to balance the _remblai_ and _deblai_, that is, the amount of earth in the parapets with that excavated from the ditches. In practice such niceties of course disappeared, though occasionally when the ground allowed of it star forts and bastioned fronts were employed.

On irregular ground the first necessity was to fit the redoubt to the ground on which it stood, so as to sweep the whole of the foreground, and this was generally a sufficiently difficult matter without adding the complications of flanking defences. Sir John Jones, speaking of the traces of the several works in the Torres Vedras lines, says:--

Torres Vedras.

"The redoubts were made of every capacity, from that of fig. 74 a,
limited by want of space on the ground it occupied to 50 men and two
pieces of artillery, to that of fig. 74 b, for 500 men and six pieces
of artillery, the importance of the object to be attained being the
only guide in forming the dimensions. Many of the redoubts first
thrown up, even some of the smallest, were shaped like stars, under
the idea of procuring a flank defence for the ditches; but this
construction was latterly rejected, it being found to cut up the
interior space, and to be almost fallacious with respect to flank
defence, the breadth of the exterior slopes being in some cases equal
to the whole length of the flanks so obtained. Even when, from the
greater size of the work, some flanking fire was thus gained, the
angle formed by the faces was generally so obtuse that it demanded
more coolness in the defenders than ought reasonably to be expected to
aim along the ditch of the opposite face: and further, this
construction prevented the fire of the work being more powerful in
front than in rear.

In order to decide on the proper trace of a work, it is necessary to
consider whether its object be to prevent an enemy establishing
himself on the ground on which it is to be placed, or whether it be to
insure a heavy fire of artillery on some other point in its vicinity.
In the first case every consideration should be sacrificed to that of
adding to its powers of self-defence by flanks or other expedients. In
the second, its powers of resistance are secondary to the
establishment of a powerful offensive fire and its trace cannot be too
simple. Latterly, the shape of the redoubts was invariably that most
fitted to the ground, or such as best parried the enfilade fire or
musketry plunge of neighbouring heights, care being taken to present
the front of fire deemed necessary towards the pass, or other object
to be guarded; and such will generally be found the best rule of
proceeding.

This recommendation, however, is not intended to apply to isolated
works of large dimensions, and more particularly to those considered
the key of any position. No labour or expense should be spared to
render such works capable of resisting the most furious assaults,
either by breaking the parapet into flanks, or forming a flank defence
in the ditch; for the experience gained in the Peninsula shows that an
unflanked work of even more than an ordinary field profile, if
skilfully and determinedly assaulted, will generally be carried....
Nor does the serious evil of curtailing the interior space, which
renders breaks in the outline so objectionable in small works, apply
to works of large dimensions.... Under this view the great work on
Monte Agraca (fig. 75) must be considered as very defective, the flank
defence being confined to an occasional break of a few feet in the
trace, caused by a change of direction in the contour of the height,
whilst the interior space is more than doubly sufficient for the
number of its allotted garrison to encamp.

_Interior and other Defences._--This work, however, had some of its
salient points ... cut off by earthen lines of parapet, steeply
revetted externally, and so traced as to serve for traverses to the
interior. It had also three or four small enclosed posts formed within
it; and the work at Torres Vedras (fig. 76) had each of its salient
points formed into an independent post. These interior defences and
retrenchments were intended to guard against a general panic amongst
the garrison, which would necessarily be composed in part of
indifferent troops, and also to prevent the loss of the work by the
entry of the assailants at any weak or ill-defended point. Such
interior lines to rally on are absolutely essential to the security of
a large field-work. They serve as substitutes for a blockhouse or
tower, placed in the interior of all well-constructed permanent
earthen works, and merit far more attention than they generally
receive.

The small circular windmills of stone, which were frequently found
occupying salient knolls ... readily converted into admirable interior
posts of that nature. The profile of the several works varied on every
face and flank, according to its liability to be attacked or
cannonaded; the only general rule enforced being that all ditches
should be at least 15 ft. wide at top and 10 ft. in depth, and the
crest of the parapet have at least 5 ft. command over the crest of the
counterscarp. No parapet exceeded 10 ft. in thickness, unless exposed
to be severely cannonaded, and few more than 6 or 8 ft.; and some, on
high knolls, where artillery could not by any possibility be brought
against them, were made of stone or rubble less than 2 ft. in
thickness, to gain more interior space, and allow full liberty for the
use of the defenders' bayonets."

Fig. 77 gives two typical sections of these works.

The works of Torres Vedras have been chosen for illustration because they offer very good historical examples, and also because of the value of the critical remarks of Sir John Jones, who as a captain was the engineer in charge of their construction. At the same time it must be remembered that they differ from ordinary field-works in having an unusual degree of strength, plenty of time and civilian labour having been available for their construction. In this respect they approximate more to semi-permanent works, the main reason why they did not receive under the circumstances a greater development of ditch and parapet being that in addition to the large number of works required, much labour was expended in abatis, inundations, scarping hill-sides and constructing roads.

Some further remarks of Sir John on the _situations of the works_ are very instructive:--

"Many of the redoubts were placed on very elevated situations on the
summit of steep hills, which gave them a most imposing appearance;
but it was in reality a defect ... for the fire of their artillery on
the object to be guarded became so plunging as to lose half its
powers; the musketry could not be made to scour the face of the hill
sufficiently; and during the night both arms became of most uncertain
effect.

"The domineering situation of the redoubts, however, gave confidence
to the young troops which composed their garrisons, protected them
from a cannonade, and screened their interior from musketry, unless
fired at a high angle, and consequently at random. These
considerations perhaps justify the unusually elevated sites selected
for most of the redoubts on the lines, though they cannot induce an
approval of them as a general measure."

The chief principle of the period was thus that the redoubts were the most important features of lines of defence, and that they combined physical obstacle and protection with good musketry and artillery positions. The value of concealment was not ignored, but it was as a rule subordinated to other considerations.

19th century.

The principles of this time remained unaltered until after the Crimean War. In the American Civil War the power of the rifle began to assert itself, and it was found that a simple breastwork defended by a double rank of men could protect itself by its fire against an ordinary assault. This power of the rifle gave greatly enhanced importance to any defences that could be hastily extemporized behind walls, hedges or any natural cover. About the period of the Franco-German War other considerations came in. The increased velocity of artillery projectiles reduced in some ways their destructive effects against earth parapets, because the shell had an increasing tendency to deflect upwards on striking a bank of loose earth. Also the use of shrapnel made it impossible for troops to find cover on the terreplein of a work some distance behind the parapet.

These considerations, however, were not fully realized at that time. The reason was partly a want of touch between the engineers and the non-technical branches of most armies, and partly that original writers from the Napoleonic wars to the present day have been more occupied with the primary question of the value of field defences as a matter of tactics than with their details considered from the standpoint of fortification.

There was always an influential school of writers who declaimed against all defences, as being injurious to the offensive spirit so essential to success. Those writers who treated of the arrangements of defences devoted themselves to theoretical details of trace quite after the old style; discussing the size and shape of typical redoubts, their distance apart and relation to lines of trenches, &c. The profiles--the thick parapet with command of 7 ft. or more, the deep ditch, and the inadequate cover behind the parapet--remained as they had been for a century.

The American Civil War showed the power of rifles behind slight defences. Plevna in 1877 taught a further lesson. It proved the great resisting power of extemporized lines; but more than that, we begin to find new arrangements for protection against shell fire (see plans and sections in Greene's _The Russian Army and its Campaign in Turkey_). The trace of the works and the sections of parapet and ditch suggest Torres Vedras; but a multiplication of interior traverses and splinter-proof shelters show the necessity for a different class of protection. The parapet was designed according to the old type, for want of a better; the traverses and shelters were added later, to meet the necessities of the case. The Turks also used two or three tiers of musketry fire, as for instance one from the crest of the glacis, one from the parapet, and one from a traverse in rear of it. This, however, is a development which will not be necessary in future, thanks to magazine rifles.

Principles of modern field defences.

From 1877 to 1899 the efficiency of rifles and guns rapidly increased, and certain new principles, causing the field defences of the present day to differ radically from those of the 18th century, remained to be developed. These may be considered under the following heads: the nature of protection required, the diminished need of obstacle, and the adaptation of works to ground.

The principle that _thickness_ of parapet is no longer required, to resist artillery fire, was first laid down at Chatham in 1896. The distance at which guns now engage makes direct hits on parapets comparatively rare. Further, a shell striking near the crest of a parapet may perhaps kill one man if he is in the way, and displace a bushel of earth. That is nothing. It is the contents of the shell, whether shrapnel or explosive, that is the source of danger and not the shell itself. Thus the enemy's object is to burst his common shell immediately behind the parapet, or his shrapnel a short distance in front of it, in order to get searching effect. It follows that a parapet is thick enough if it suffices to stop rifle bullets, since the same thickness will _a fortiori_ keep out shrapnel bullets or splinters of shell. For this purpose 3 ft. is enough.

Real protection is gained by a trench close in rear of the parapet, deep enough to give shelter from high angle shrapnel, and narrow enough to minimize the chance of a common shell dropping into it. This protection is increased by frequent traverses across the trench.

The most essential point of all is _concealment_. In gaining this we say good-bye finally to the old type of work. Protection is now given by the trench rather than the parapet; command and the ditch-obstacle (which furnished the earth for the high parapet) are alike unnecessary. Concealment can therefore be studied by keeping the parapet down to the lowest level above the surface from which the foreground can be seen. This may be 18 in. or less.

The need of obstacle, in daylight and when the defenders are not abnormally few, has practically disappeared. For night work, or when the assailant is so strong as to be able to force home his attack in face of protected rifle fire, what is needed is not a deep ditch immediately in front of the parapet, difficult to climb, but also difficult to flank, but an obstacle that will detain him under fire at short range. It may be an entanglement, an abatis, an inundation: anything that will check the rush and make him move slowly.

In the _adaptation of works to ground_, the governing factor is the power of the rifle in frontal defence. We have seen that in Peninsular times great reliance was placed on the flanking defence of lines by guns in redoubts. Infantry extended behind a simple line of trench could not resist a strong attack without such support. Now, however, infantry behind a slight trench, with a good field of fire should be able to defend themselves against any infantry attack.

This being so, the enemy's artillery seeks to locate the trenches and to cover them with a steady hail of shells, so as to force the defenders to keep down under cover. If they can succeed in doing this, it is possible for the attacking infantry to advance, and the artillery fire is kept up until the last moment, so that the attack may have the narrowest possible space to cover after the defenders have manned their parapets and opened fire. Fig. 78 shows the action of various natures of projectiles.

FIG. 78.--Effect of Projectiles.]

We need not here discuss the role of the defenders' artillery in replying to that of the enemy and playing on the attack; nor for the moment consider how far the defence of the trenches while under artillery fire can be made easier by overhead cover. The main question is--what is, in view of the nature of the attack, the best disposition of lines of trench; and do they require the addition of redoubts?

The most important point, with the object of protection, is that the trenches must not be conspicuous; this is the best defence against artillery. With the object of resistance by their own fire they must have a good view, or, as it is generally described, no _dead ground_ in front of them. For this purpose 300 or 400 yds. may be enough if the ground is even and affords no cover.

This necessity for invisibility, together with the shallowness of the zone that suffices for producing a decisive fire effect, has of late years very much affected the choice of ground for a line of trenches.

Siting of trenches.

For a defensive position on high ground, it was usually laid down
until the South African War that a line of trenches should be on the
"military crest" (Fr. _crete militaire_), _i.e._ the highest point on
the hill from which the whole of the slopes in front can be seen. Thus
in the three sections of ground shown in fig. 79 it would be at a, b
and c respectively. The simplicity of this prescription made it
attractive and it came to be rather abused in the text-books. There
were, even before the improvements in artillery, objections to it,
because on most slopes the military crest would be found at very
different elevations on different parts of the line, so that by a
strict adherence to the rule some of the trenches would be placed near
the top of the hill, and some in dangerous isolation near the bottom.
Moreover a rounded hill has no military crest.

Further, we have to consider nowadays not only the position of the
fire-trenches, but those of supports, reserves and artillery, and the
whole question is extremely difficult.

For instance, considering the sections alone, as if they did not vary
along the line, the positions at _a_ and _b_, fig. 79, are bad because
they are on the sky-line and therefore a good mark for artillery. That
at _b_ is especially bad because the slope in front is so steep that
the defenders would have to expose themselves very much to fire down
it, and the artillery fire against them can be kept up until the very
last moment. The position _c_ has the advantage of not being on the
sky-line, but the position of the supports in rear is exposed.

Such a position as that at _d_, fig. 80, is good, but protected or
concealed communications must be made for the supports coming from _e_
over the brow of the hill.

Another possible position for the infantry line is at _f_, fig. 81,
with the guns on the high ground behind. They might easily be quite
concealed from the enemy's artillery. The drawback is that no
retirement up the exposed slope would be possible for them, except at
night. The fire from _f_ will be _grazing_, which will be a great
advantage as compared with the _plunging_ fire that would be obtained
from a position up the hill.

It is idle, however, to give more than the most cursory consideration
to sections of imaginary positions. It is only by actual practice on
the ground that skill can be attained in laying out positions, and
only a trained soldier with a good eye can succeed in it. Briefly, the
advantages of view and position given by high ground must be paid for
in some degree by exposure to the enemy's artillery; and at least as
much consideration--possibly as much labour--must be given to
communications with the fire-trenches as to the trenches themselves.
Irregular ground simplifies the question of concealment but also gives
cover to the enemy's approach. The lie of the ground will itself
dictate the position of the trenches, subject to the predispositions
of the responsible officer. On flat featureless ground the general
trace of the trenches should be irregular. This makes a more difficult
target for artillery, and affords a certain amount of cross and
flanking fire, which is a very great advantage. Great care should,
however, be taken not to expose the trenches to oblique or enfilade
fire; or at least to protect them, if so exposed, by traversing.

Trenches.

Concealment of trenches is generally attempted by covering the freshly
turned earth of the small parapet with sods, leafy branches or grass.
In this connexion it should be remembered that after a day or two cut
leaves and grass wither and may become conspicuous against a green
surface. Where the ground is so even that a good view of the
foreground is possible from the surface level, the trench may be made
without a parapet; but this entails great labour in removing and
disposing of the excavated earth. A common device is to conceal the
parapet as well as possible and to make a dummy trench some distance
away to draw fire.

Besides the direct concealment of trenches, care must be taken that
the site is not conspicuous. Thus a trench should not be placed along
the meeting line of two different kinds of cultivation, or along the
edge of a belt of heather on a hill-side, or where a difference of
gradient is sharply defined; or where any conspicuous landmark would
help the enemy's artillery to get the range.

Trenches are broadly distinguished as "fire trenches" and "cover
trenches," according as they are for the firing line or supporting
troops. The following simple types are taken from the 1908 edition of
_Military Engineering_ (part 1): "Field Defences."

Fig. 82 is the most common form of fire trench, in which labour is
saved by equalizing trench and parapet. This would take 1-1/2 to 2
hours in ordinary soil. Fig. 83 shows the same trench improved by 2 or
3 hours' more work. Fig. 84 shows a fire trench without parapet, with
cover trench and communication.

FIG. 84.]

The addition of a loophole of sandbags on the top for concealment
(called _head-cover_), gives increased protection, but at the cost of
greater prominence for the parapet (fig. 85). Overhead cover can only
be provided in fire trenches by giving the parapet still greater
height and it is not usually done. Portions of the trench not used for
firing can, however, be given splinter-proof protection by putting
over them branches or bundles, covered with a few inches of earth: or
by boards, or sheets of corrugated iron if they can be had. A better
plan when time permits is to provide cover trenches immediately behind
and communicating with the fire trench.

FIG. 85.]

Redoubts.

The question of redoubts has been a vexed one for years; partly they
were thought to be unnecessary in view of the resisting power of a
line of trenches, but chiefly because the redoubt was always imagined
as one of the older type, with a high conspicuous parapet. Of course a
redoubt of such a nature would be readily identified and made
untenable. But the idea of a redoubt does not necessarily imply
command. Its object is that it shall be capable of all-round defence.
There can be no doubt that as there is always a possibility of lines
being pierced somewhere, it is desirable, unless the whole line is to
be thrown into confusion and forced back, to have some point at which
the defenders can maintain themselves. This is not possible unless at
such points there is provision for defence towards both flanks and
rear, that is to say, when there are redoubts, which can hold on after
certain portions of the line have been lost and thereby can localize
the enemy's success and simplify the action of supporting troops. In
order that redoubts may exercise this function, all that is necessary
is that their defenders should be able to see the ground for a furlong
in front of them in every direction. Their parapets, therefore, need
be in no way more conspicuous than those of the neighbouring fire
trenches, and in that case there is no fear of their drawing special
attention from the enemy's artillery. Whatever theories may have been
put forward en the subject, in practice they are constantly used, and
in the Russo-Japanese War, where the experience of South Africa was
already available, we find them in the fighting lines on both sides.

The modern type of field redoubt is a fire trench, no more conspicuous
than the others, in any simple form adapted to the ground that will
give effective all-round fire, such as a square with blunted angles.
Enhanced strength may be given by deepening the trenches and improving
the overhead cover; and special use may here be made of obstacles.

Within the redoubt cover may be provided for men in excess of those
required to man the parapet, by means of cover trenches and field
casemates. Fig. 86 gives the general idea of such a redoubt, and figs.
87, 88 the plan and section of the interior shelters. Such a work can
easily be made quite invisible from a distance. It gives excellent
cover against shrapnel, but would not be tenable against howitzer
common shell, if the enemy did manage to bring an accurate fire to
bear on it.

Fig. 89 shows the section of a parapet with two shelters behind it for
a work with a high command of 5 or 6 ft. This work would require a
concealed position, which can often be found a little in rear of the
firing line.

FIG. 89.]

Boer, Russian and Japanese types.

In the South African War a good deal of interest was excited by a type
of trench used by the Boers. It was very narrow at the surface, giving
only just room for a man to stand; but undercut or hollowed out below,
so that he could sit down with very good cover. Such a section is
only possible in very firm soil. Apart from this, the type is really
only suited to rifle pits, as a trench proper should have room for
officers and N.C.O's to move along within it. The Boers showed great
skill in concealing their trenches. One good point was that there was
generally something making a background immediately behind the men's
heads, so that they did not stand out in relief when raised above the
parapet.

FIGS. 90 and 91.]

In the Russo-Japanese War the Russian trenches at the outset were of
old-fashioned type and very conspicuous. Later on better types were
evolved. Figs. 90 and 91 are a couple of sections from Port Arthur;
the first borrowed from the Boers but wider at the top. The Japanese
appear to have taken their type mainly from the latest British
official books, but applied them with great skill to the ground
studying especially invisibility. In their prepared positions they
used large redoubts manned by several companies.

FIG. 92.--Gun-pit.]

_Cover for Guns._--Some degree of cover for guns, in addition to the
shield, is always desirable. If the gun stands on the natural surface
of the ground, the cover is called an epaulment. In that case a bank
is thrown up in front of the gun, about 1 ft. high in the centre, and
3 ft. 6 in. high at the ends. On either side of the gun and close up
to the bank is a small pit for the gunners. The rest of the earth for
the epaulment is got from a trench in front. If the gun is sunk, the
shelter is called a gun-pit.

In this case there is no bank immediately in front of the gun. Shelter
can be got more quickly with a pit than an epaulment, but it is
generally undesirable to break the surface of the ground.

Obstacles.

The commonest forms of _obstacle_ now used are _abatis_ and _wire
entanglements_. Fig. 93 shows a well-finished type of abatis. The
branches are stripped and pointed, and the butts are buried and pegged
firmly down. Wire entanglement may be added to this with advantage. An
abatis should be protected from artillery fire, which is sometimes
done by placing it in a shallow excavation with the earth thrown up in
front of it.

FIG. 93.--Abatis.]

Wire may be used as a _high_ or _low entanglement_ or as a fence or
trip wire or concealed obstacle. The usual form of high wire
entanglement consists of several rows of stout stakes 4 or 5 ft. long,
driven firmly into the ground about 6 ft. apart, and connected
horizontally and diagonally with barbed wire.

_Palisades_ are still used, and need no description. They were
formerly often made bullet-proof, but this is no longer possible.
_Fraises_ are seldom heard of now, though they may appear occasionally
in a modified form. They were much used in connexion with deep
ditches, and are palisades placed so as to project horizontally from
the escarp, or sloping forward in the bottom of the ditch. _Military
pits_ both _deep_ and _shallow_ (the latter, shown in fig. 95, called
_trous de loup_) are not so much used as formerly, because the
obstacle is hardly worth the labour expended on it. Both, however,
were employed in the Russo-Japanese War. _Crows' feet_, formerly much
used as a defence against cavalry, are practically obsolete. They
consisted of four iron spikes joined together at their bases in such a
manner that however they were thrown down one point would always be
pointing upwards (fig. 94). _Chevaux-de-frise_ (q.v.) were formerly a
much-used type of obstacle.

The best obstacle is that which can be made to fulfil a given object
with the least expenditure of time and labour. From this point of view
barbed wire is far the best. One of its greatest advantages is that it
gives no cover whatever to the enemy.

_Fougasses_ have always for convenience been classed as obstacles. A
fougasse is a charge of powder buried at the bottom of a sloping pit.
Over the powder is a wooden shield, 3 or 4 in. thick, and over the
shield a quantity of stones are piled. The illustration, fig. 96,
gives a clear idea of the arrangement. A fougasse of this form,
charged with 80 lb. of powder, will throw 5 tons of stones over a
surface 160 yds. long by 120 wide. They may be fired by powder hose,
fuze or electricity. Their actual effect is very often a matter of
chance, but the moral effect is usually considerable.

_Dams_ are most effective obstacles, when circumstances allow of their
use. They are constructed by military engineers as small temporary
dams would be in civil works.

Illumination.

A most important question, especially in connexion with obstacles, is
that of lighting up the foreground at night. Portable electric
searchlights are most valuable, especially for detecting the enemy's
movements at some distance; but their use will naturally always be
restricted. Star shells and parachute lights fired from guns are not
of much use for the immediate foreground, and do not burn very long.
They were formerly chiefly of use in siege works, to light up an
enemy's working parties. Germany has introduced lightballs fired from
pistols, which will probably have a considerable future.

Various civilian forms of _flare-light_ would be very useful to
illuminate obstacles, but cannot well be carried in the field.
_Bonfires_ are very useful when material is available. They require
careful treatment, _e.g._ they must be so arranged that they can be
lighted instantaneously (they may be lighted automatically, by means
of a trip wire and a fuze); they must give a bright light at once
(this can be ensured with shavings or straw sprinkled with petroleum);
they must be firmly built so that the enemy cannot destroy them
easily; and if possible there should be a screen arranged behind them
so that they may not light up the defence as well as the attack.

Blockhouses.

Blockhouses are familiar to the public from the part they played in
the South African War of 1899-1902. In the old-fashioned permanent
fortification they were used as keeps in such positions as re-entering
places of arms and built of masonry. Stone blockhouses have long been
used in the Balkans for frontier outposts; they are sometimes built
cruciform, so as to get some flanking defence. In the form of
bullet-proof log-cabins they have played a great part in warfare
between pioneer settlers and savages.

FIG. 96.--Fougasse.]

In the 19th century blockhouses were usually designed to give partial
protection against field artillery; the walls being built of two
thicknesses of logs with earth between them, the roof flat and covered
with 2 or 3 ft. of earth, and earth being piled against the walls up
to the loopholes. Nowadays they are employed only in positions where
it is not likely that artillery will be brought against them: but they
may be made tenable for a while even under artillery fire if they are
surrounded by a trench and parapet.

Blockhouses are especially useful for small posts protecting such
points as railway bridges, which the enemy may attempt to destroy by
cavalry raids. The essential feature is a bullet-proof loopholed wall,
arranged for all-round fire, with enough interior space for the
garrison to sleep in. The roof may be simply weatherproof. Some
arrangement for storing water must be provided. Circular blockhouses
were very popular in South Africa. They were made of sheets of
corrugated iron fastened 6 in. apart on a wooden framework, the space
between the sheets being filled with small stones. The loopholes were
made of sheet-iron frames inserted in the walls. Fig. 97 shows a
section of one of these blockhouses.

FIG. 97.--Blockhouse, South Africa, 1900-1902.]

Woods.

The defence of woods was formerly an important branch of field
defences. Abatis and entanglements could readily be extemporized,
trunks of trees made strong breastworks, and the wood concealed the
numbers of the defenders. A wood was therefore generally considered a
useful addition to a line of defence. It was customary to hold the
front edge of the wood, the irregularities of the outline being
utilized for frontal and flanking fire, while obstacles were disposed
some 50 yds. in front. In a carefully prepared position, clearings
would be made parallel to the front and some distance back from it,
for support positions, and great attention was paid (in theory at
least) to clearing communications, erections, signposts, &c., so that
the defending troops might move freely in any desired direction.

Woods, however, had their inherent drawbacks. The ground is hard to
dig, clearing involves great labour; and communication, at the best,
is cramped. Nowadays a wood can hardly be considered a strong
defensive element in a line. The front of it is an excellent ranging
mark for artillery, and positions within the wood are not easily made,
because of the difficulty of trenching, and the fact that no
reasonable amount of timber will make a breastwork proof against the
modern bullet. Once an enemy gets a footing within a wood, the
position is more favourable to offensive than to defensive action. If
a wood has to be occupied in a line of defence, it is probable that in
most cases the rear edge or a line slightly behind it would be the
best to fortify, though the front edge would no doubt be held by the
fighting line at the outset.

Villages.

The defence of villages is another question which has been much
affected by recent improvements in artillery. Formerly villages were
very important adjuncts to a line of defence, and strong points for a
detached force to hold. There were indeed always drawbacks. The
preparations for defence entailed a good deal of labour, and the
defending force was scattered in houses and enclosures, so that
control and united action were difficult. But the value of the
ready-made protection afforded by walls was so great--and sometimes
even decisive--that villages were occupied as a matter of course. This
is certainly now changed, but precisely to what extent it will be
impossible to say, until after the next European war. A village under
fire is not now an ideal defensive position. A single shrapnel
penetrating the outer wall may kill all the occupants of a room; a
single field-howitzer shell may practically ruin a house. At the same
time, a house or line of houses may (without any preliminary labour at
all) give very good protection against shell fire to troops _behind_
them. Further, the value to the defence of the slightest cover, once
the infantry attack has developed, is so great that the ruins of walls
and houses occupied at the right moment may prove an impregnable
stronghold. This class of fighting, however, does not properly come
under the present heading. For the details of the defence of walls,
houses, &c., see the official _Mil. Engineering_ (1908).

_Entrenching under Fire._--Progress in this direction has been delayed
by the reluctance of military authorities to add a portable
entrenching tool to the heavy burden already carried by the infantry
soldier. Further delay has resulted from the attempts of enthusiastic
inventors to produce a tool that shall weigh nothing, go easily in the
pocket, and be available as a pick, shovel, saw, hand-axe or
corkscrew. A tool that will serve more than one use is seldom
satisfactory for any.

Extemporized cover.

The object of entrenching under fire is to enable attacking infantry,
when their advance is checked by the enemy's fire, to maintain the
ground they have won by extemporizing cover where none exists. The
need of this was first felt in the American Civil War, and towards the
close of it a small entrenching spade 22 in. long and weighing only
1-1/2 lb. was introduced by Brigadier-General H.W. Benham into the
Army of the Potomac. Since that time a great number of patterns have
been tried, including shovel, trowel and adze types. The most popular
of these has been the Linnemann spade, which is used by most
continental armies and by the Japanese. The Austrian form of this tool
is a rectangular spade with straight handle. The length over all is a
little less than 20 in. The blade is 8 in. long by 6 wide. One side of
it has a saw edge, and the other a cutting edge. For carriage, the
blade is enclosed in a leather case, which is strapped to the pack or
the waist-belt. In the British army the Wallace combined pick and
shovel was used for some time, but was eventually dropped. There was
always great doubt whether the utility of a portable entrenching tool
was such as to justify the inconvenience caused to the soldier in
carrying it. But the experience of the Russo-Japanese War seems to
have finally established the necessity of it, and also the fact that
it must generally be used lying down. For this purpose and for
convenience in carrying it on the person, a very light short-handled
tool is required.

The soldier lying down cannot attempt to dig a trench, but can make a
little hole by his side as he lies, and put the earth in front of his
head. A method introduced by the Japanese is that at each check in the
advance the front line should do this, and, as they go forward, the
supporting lines in succession should improve the cover thus
commenced.

General remarks.

There are few things that soldiers dislike more, in the way of
training, than trenchwork. For men unused to it, it is tiring and
tedious work, and it is difficult for them to realize its importance.
At the same time it is a commonplace of recent history that men who
have been in action a few times develop a great affection for the
shovel. The need of trenches grows with the growth of firearms, and
the latest feature of modern tactics is the use of them in attack as
well as in defence. The observation has often been made--with what
truth as a general proposition we cannot here discuss--that modern
battles tend more and more to resemble a siege. The weaker side, it is
said, entrenches itself; the other bombards and attacks. After gaining
as much ground as they can, the attacking troops wait for nightfall
and entrench; perhaps making a further advance and entrenchment before
dawn. In the last stage the attack might even be reduced to gaining
ground by sapping. In open and featureless ground, where the rifle and
gun have full play, the trench is to the modern soldier very much what
the breast-plate was to the man-at-arms, an absolute essential.

The most important point in connexion with modern field fortification
is the effect on both strategy and tactics of the increased resisting
power of the defence. A small force well entrenched can check the
frontal attack of a very much larger force, and while holding its
position can make itself felt over a wider radius than ever before.
This must needs have a marked effect on strategy, and it is quite
possible to foresee such an ultimate triumph of field fortification as
that one force should succeed in surrounding another stronger than
itself, and by entrenching prevent the latter from breaking out and
compel its surrender.

VI. CONCLUSION

In tracing the history of the science of fortification and in outlining the practice of our own time it has been necessary to dwell chiefly on the material means of defence and attack. The human element has had to be almost ignored. But here comes in the paradox, that the material means are after all the least important element of defence. Certainly it is inconceivable that the designer of a fortress should not try to make it as strong as is consistent with the object in view and the means at his disposal. And yet while engineers in all ages have sought eagerly for strength and refinements of strength, the fact remains that the best defences recorded in history owed little to the builder's art. The splendid defence in 1667 of Candia, whose enceinte, of early Italian design, was already obsolete but whose capture cost the Turks 100,000 men; the three years defence of Ostend in 1601; the holding of Arcot by Clive, are instances that present themselves to the memory at once. The very weight of the odds against them sometimes calls out the best qualities of the defenders; and the _man_ when at his best is worth many times more than the _rampart_ behind which he fights. But it would be a poor dependence deliberately to make a place weak in order to evoke these qualities. One cannot be sure that the garrison will rise to the occasion, and the weakness of the place has very often been found an excuse for giving it up with little or no resistance.

Very much depends on the governor. Hence the French saying, "tant vaut l'homme, tant vaut la place." Among modern men we think of Todleben (not governor, but the soul of the defence) at Sevastopol, Fenwick Williams at Kars, Denfert-Rochereau at Belfort, and Osman Pasha at Plevna. The sieges of the 16th and 17th centuries offer many instances in which the event turned absolutely on the personal qualities of the governor; in some cases distinguished by courage, skill and foresight, in others by incapacity, cowardice or treachery. The reader is referred to Carnot's _Defense des places fortes_ for a most interesting summary of such cases, one or two of which are quoted below.

The spirit of the defence.

Naarden was besieged by the prince of Orange in September 1673 and defended by Philippe de Proce, sieur Dupas. The duke of Luxemburg visited the place some hours before it was invested, and arranged with Dupas to relieve him as soon as he had collected his cavalry. But the governor lost his head when he saw the enemy encamped round the place, and surrendered it before he had even lost the covered way. He was subsequently tried by a council of war and sentenced to be degraded before the troops and imprisoned for life. The reason the court gave for not condemning him to death was that they could find no regulation which condemned a man to loss of life for being a coward. (At that period the decapitation of a governor who was considered to have failed in his duty was not uncommon.) This man, however, was not wanting in physical courage. He was in prison at Grave when it was besieged a year later, obtained leave to serve as a volunteer in the defence, fought well and was killed.

A similar case occurred in the English Civil War. In 1645 the young governor of the royal post at Bletchingdon House was entertaining a party of ladies from Oxford, when Cromwell appeared and summoned him to surrender. The attacking force had no firearm more powerful than a carbine, but the governor, overawed by Cromwell's personality, yielded. Charles I., who was usually merciful to his officers, caused this governor to be shot.

A defence of another kind was that of Quilleboeuf in 1592. Henry IV. had occupied it and ordered it to be fortified. Before the works had been well begun, Mayenne sent 5000 men to retake it. Bellegarde undertook its defence, with 115 soldiers, 45 gentlemen and a few inhabitants. He had ammunition but not much provisions. With these forces and a line of defence a league in length, he sustained a siege, beat off an assault on the 17th day, and was relieved immediately afterwards. The relieving forces were astonished to find that he had been defending not a fortified town but a village, with a ditch which, in the places where it had been begun, measured no more than 4 ft. wide and deep.

At that period the business aspect of siege warfare already alluded to had been recognized, but many commanders retained the old spirit of chivalry in their reluctance to say the "loth word." The gallant Marshal d'Esse, who feared nothing but the idea of dying in his bed, was lying ill at his country house when he was sent for by the king. He was ordered to take command at Therouanne, then threatened by Charles V., and made his farewell with these words, which remind us somewhat of Grenville: "Sire, je m'y en vais donc de bon et loyal coeur; mais j'ai oui dire que la place est mal envitaillee, non pas seulement pourvue de palles, de tranches, ni de hottes pour remparer et remuer la terre; mais lors, quand entendrez que Therouanne est prise, dites hardiment que d'Esse est gueri de sa jaunisse et mort." And he made good his word, for he was killed at the breach by a shot from the arquebus of a Spanish soldier.

Sometimes the ardour of defence inspired the whole body of the inhabitants. Fine examples of this are the defences of Rochelle (1627) and Saint-Jean de Lone (1636), but these are too long to quote. We may, however, mention Livron, which is curious. In 1574 Henry III. sent one of his favourites, Saint Lary Bellegarde, against the Huguenots in the Dauphine. Being entrusted with a good army, this gentleman hoped to achieve some distinction. He began by attacking the little town of Livron, which had no garrison and was defended only by the inhabitants. But he was repulsed in three assaults, and the women of the town conceived such a contempt for him that they came in crowds to empty their slops at the breach by way of insult. This annoyed him very much, and he ordered a fresh assault. The women alone sustained this one, repulsed it lightheartedly, and the siege was raised.

Arcot.

The history of siege warfare has more in it of human interest than any other branch of military history. It is full of the personal element, of the nobility of human endurance and of dramatic surprises. And more than any battles in the open field, it shows the great results of the courage of men fighting at bay. Think of Clive at Arcot. With 4 officers, 120 Europeans and 200 sepoys, with two 18-pounders and 8 lighter guns, he held the fort against 150 Europeans and some 10,000 native troops. "The fort" (says Orme) "seemed little capable of sustaining the impending siege. Its extent was more than a mile in circumference. The walls were in many places ruinous; the rampart too narrow to admit the firing of artillery; the parapet low and slightly built; several of the towers were decayed, and none of them capable of receiving more than one piece of cannon; the ditch was in most places fordable, in others dry and in some choked up," &c. These feeble ramparts were commanded almost everywhere by the enemy's musketry from the houses of the city outside the fort, so that the defenders were hardly able to show themselves without being hit, and much loss was suffered in this way. Yet with his tiny garrison, which timbered about one man for every 7 yds. of the enclosure, Clive sustained a siege of 50 days, ending with a really severe assault on two large open breaches, which was repulsed, and after which the enemy hastily decamped.

Such feats as this make arguments about _successive lines of defence_ and the _necessity of keeps_ seem very barren. History, as far as the writer knows, shows no instances where successive lines have been held with such brilliant results.