of a field army which happened to be operating in the neigh-
bourhood, and the town was in practice defended sometimes
with spirit, sometimes feebly whatever course operations took
outside. Up to the very eve of the World War a French fortress
governor was responsible to the Government only, and took no



orders from the commander-in-chief of the field armies. The
era of " cabinet wars " made little difference to this state of
things; the population might be indifferent to the war in the
towns as in the country, but to the governor and his troops the
fortress was still a charge to be defended. Moreover, it was a
real base for the armies in the field, in that the stores and supplies
for those armies were accumulated in the fortress, and a real
strategic aid in that it commanded routes that were obligatory
for both sides. But when, in our own times, the governor had
become simply the commander of a certain group of forces
destined like other forces to take their part in a general scheme
of battle; when the area within his defences had to a great extent
ceased to be the source of stores and supplies for the field army,
and when railways, needing protection at all points and not
merely at a focus, became the principal lines of communication,
the choice between evacuation and defence came to be governed
by larger considerations of strategy. The governor's decisions
therefore were assimilated in principle to those of any tactical
executant of the strategist's instructions. He might defend or
evacuate as a field commander might hold his ground or retire.
But the peculiar character of his responsibility was gone. Even
in France, the country which has been most tenacious of the
fortress tradition, the old regulation, already quoted, was modi-
fied in the 1913 " Regulations for the conduct of Higher Forma-
tions," which empowered the commandcr-in-chief to assume con-
trol of any fortress and its forces if he thought fit. 1

On the German side, units made up from fortress garrisons
formed quite one- third of the Eastern armies during the first cam-
paignsof 1914 operating sometimes a hundred miles away from
their fortress of origin and in the sequel, never returning to it.

In sum, therefore, causes of a general character operating
before 1914 produced these tendencies: (a) to divorce fortifica-
tions from their nucleus or central town, (b) to make them rather
linear than circular in trace, (c) to bring them into conformity
with the battle-scheme of the field armies (with dtdassemtnt as
the alternative), and (d) to construct them as far as possible
according to the principles of field fortification.

The theory of fortification, on the other hand, was still bound
by the notion of a nucleus, and unable, therefore, for the mo-
ment to employ its stock of ideas and methods to the best ad-
vantage. The practical technique of fortification and siegecraft
was, meantime, progressing in details; reinforced concrete had
come into normal use, armour was improving in quality, the
defence had it in its power no less than the attack to profit by
developments in the design of quick-firing guns and howitzers of
medium calibres. Observation balloons and kites were available,
superior to the old spherical types; wireless telegraphy removed
some of the dangers of investment and made it possible to co-
ordinate the activity of a besieged garrison with that of a relieving
army. The technique of bored mines developed, and trench-
mortars and grenades reappeared. The lessons of Port Arthur
in matters of detail-tactics and design were assimilated in the
various armies. The enormous defensive power of the machine-
gun was realized and to some extent exploited. It remained to
synthesize the application of these elements, old and new, in an
art of fortification that responded to the new demands and con-
ditions of warfare.

This art began to take shape with the introduction of the
" group " principle. Advocated by several theoretical writers in
the period of controversy, it was applied practically, and on a
large scale, by the Germans in the celebrated Feste constructed
on the Moselle and the Rhine in the last ten years before the

1 It was in virtue of this new regulation that Gallieni's Paris
forces were brought under Joffre's command in the battle of the
Marne; and in accordance with the spirit of it that Sarrail acted in
the same crisis, when, although only an army commander, he sent
imperative orders to the governor of Verdun to despatch his mobile
reserves to the battle-field of Revigny. The fact that the governor,
General Coutanceau, though himself under attack, complied with
this requisition instead of standing on his undoubted legal rights,
is itself evidence of the changed outlook of the fortress governor in
modern warfare. In a somewhat different way, the confused story
of the declassement of Lille in Aug. 1914 points the same moral.



SIEGECRAFT AND SIEGE WARFARE



473



.World War. They may be considered from two points of view:
locally, as examples of a type of fortification, and collectively as
a defensive ensemble.

The F este, as its name indicates, is rather a self-contained
fortress on a smaller scale than a fort in the old sense. Although
it forms with other such works, and with forts or batteries, part
of a defensive system which as a whole may be either linear or
circular, it contains within its own wire entanglements each of
the elements of defence artillery for counter-battery, artillery
for flanking the intervals, and infantry works for the protection
of this artillery against a close attack. But it combines them in
a way which differentiates it in principle from the types of fortifi-
cation characteristic of the 1873-1903 epoch.

In that period there were, broadly, two opposed schools of
thought, and a school of compromise. One school, fairly perhaps
designated as the French, favoured an arrangement in which the
" forts " form the close-defence element and intermediate bat-
tery-positions the distant-defence element. The opposite, or
Brialmont school, exemplified in the Liege and Namur works
(see 10.698-9 for plans), relied on a simple ring of powerful self-
contained forts, each including both these elements. Variations
within the respective schools turned chiefly on the use or non-use
of armour, some relying upon it for the protection of all defensive
weapons, others confining it to the close-defence weapons and
yet others excluding it altogether. The compromise school,
favoured by Austrian opinion, sought to modify the characters of
each type so as to combine them. In all cases, it should be added,
the intervals were intended to be garnished in war with an
improvised trench system, with its wire, its dugouts, and its
machine-gun emplacements.

The Feste, on the contrary, attempts to combine the two ele-
ments of defence without modifying either. Full security for
the long-range elements is given in principle by dispersing them,
equally full security for the close-defence armament by concen-
tration within an obstacle. To add positive or negative pro-
tection, armour is introduced wherever necessary, and loose and
" provisional " as the forms may seem to the student of earlier
fortification, it must not be forgotten that, structurally, every
detail of the Feste is a piece of permanent work.

This very warning, however, suggests that it is necessary
more necessary than ever for the student of fortification,
whether practical or theoretical, to find a satisfactory answer
to the question: What is it exactly that we require of " perma-
nent " fortification in the tactical sphere?

The role of permanent fortification, it is suggested, is to give
to the garrison or defence force a greater degree of security, and
to its armament better conditions of employment, than " pro-
visional," i.e. heavy field, fortification can give.

To prevent the enemy's guns from obliterating the defences of
the front attacked, and thus enabling his infantry to make its
way into the defended area, these guns must be counter-battered
and (if possible) destroyed, but in any case neutralized as far as
practicable. This implies a counter-battery armament on the
side of the defence. According as the guns of this armament are
exposed to enemy observation or not, they require, or they can
dispense with, fighting protection. But in both cases, and es-
pecially in the second, they require to be screened against hostile
raids or brusque infantry assaults that may develop during this
counter-battery phase, emerging perhaps from dead ground
close in front.

This protection can be given in the form of an obstacle to the
enemy's passage, so serious that a great and organized effort is
necessary to reduce it. Such an obstacle may be a deep ditch, or
a system of wire entanglements or grilles, or both. Normally,
the former is the better obstacle, but except in country already
intersected with canals, wet ditches, river-channels, the use of a
ditch requires that the armament to be protected shall be grouped
very closely. Unless, therefore, the engineer and his Government
are prepared to face the expense and provide cover of the solidest
kind 1 the ditch as obstacle is usually excluded, so far as concerns

1 As Col. J. C. Matheson has pointed out, the closer the grouping
the denser the material required to protect it.



the protection of what may be called the main armament. The
wire or grille, as compared with the ditch, is greatly inferior as
an obstacle, but much more readily created, more easily destroyed,
but more easily repaired also. Obstacles can be traversed, either
after being broken down by bombardment in advance of the
assault or by means of scaling ladders and bridges accompanying
it. As against destruction by bombardment in advance, the only
remedy of the defence is the counter-battery which entirely or
partially stops the bombarding guns. But even without such
destruction, the obstacle may be overcome by ladders and bridges,
wire cutters, petards and other appropriate means, in the course
of the assault itself, unless the work of placing these devices is
made impossible by the defenders' fire. Hence the obstacle,
whether it be ditch or wire, must be protected by a close-defence
armament, and nowadays it is generally admitted that this
armament must be a specialized organ. But how is this in its
turn to be protected against destruction or neutralization at the
critical moment? Practically by its own defensive arrangements
alone. And thus, in the element designed to guard the obstacle,
we reach the alternate unit of fortification upon which the whole
system depends, that which in the last analysis ensures for the
main armament the power of undisturbed counter-battery (in
the case of a fort d'arret of keeping the forbidden area under
steady fire).

The close-defence organ, then, has two functions to protect
other elements and to protect itself. The former presents no
particular difficulty, and is merely a question of providing the
necessary fire-power. But the latter is the critical problem of
modern fortification.

If the counter-battery guns are concentrated, as in a fort, and
the obstacle is a ditch, then quite apart from the material cover
required for these guns to enable them to fight material cover
is also needed for the close-defence organ, since its position is
practically obligatory. But the cover is obtained relatively
easily since the weapons covered are sunk to the level of the ditch-
floor, and any necessary thickness of protection can be provided
over it both on first construction and later.

But such a concentration of counter-battery methods creates
large intervals between work and work, and access to the defended
area (which with a dispersed main armament is automatically
barred by the obstacles defending this and the fire of the organ
which protects them) must be prevented by organs in the works
so placed as to control the open zone. In some systems reliance
has been placed on the counter-battery guns themselves to do
this, but modern engineer opinion generally may be said to be
opposed to this, since guns which have been engaged in the artil-
lery duel may have been put out of action by the time that they
are wanted for close-defence, and even if intact should be
wholly absorbed in their proper task. The organ providing
ditch defence, by reason of its situation is not as a rule able to
undertake control of the open intervals; and in short the only
alternatives are small cupolas or traditore batteries. The former
are open to many objections. If built into the same work as the
main armament they are almost as much exposed to premature
destruction as the latter is 2 and must be provided with fighting
protection on the same scale. If mobile, they are exceedingly
costly in proportion to the fire-power they develop. For these
reasons modern practice generally favours the traditore battery,
which is a casemated emplacement (sometimes a cupola) at or
near ground level, giving fire only to the flanks and rear of the
work, situated in the rear portion of it and protected against
bombardment to a great extent by the mass of the work itself.

But, from the nature of its duty, the site of the traditore battery
is frequently obligatory, and when it is combined inside the same
obstacle with a concentrated counter-battery armament, the
needs of the latter as to site may conflict with those of the tradi-
tore. In the avoidance of this, perhaps more than in any other

2 The cupolas of this class in the Antwerp forts suffered nearly as
severely as those of the main armament, although they were hardly
called upon to exercise their special functions, since the infantry
attack of the Germans was not pressed into the intervals before the
fire of the forts had been beaten down.



474



SIEGECRAFT AND SIEGE WARFARE



single factor, lies the central idea of group-fortification of the
Feste type. Two dissimilar elements have to be both protected
by the same obstacle and yet spaced some distance apart. But
the obstacle (in such conditions mainly wire or grille) itself re-
quires local close-defence. This " ultimate unit " has thus not
yet been arrived at. Nevertheless, this ultimate unit, in group-
fortification, has only to give short-range protection to the
obstacle, and in practice it is an infantry-manned stronghold,
designed to give fighting protection to its garrison, 1 sometimes
provided for, its own local safety with a deep ditch and sunken
flanking defences, sometimes organized with a fighting parapet
frontally commanding an artificial foreground which is wired,
but always having as its real function the protection of an ob-
stacle external to itself.

In the case of concentrated main armament, therefore, it would
seem that fighting protection for the counter-battery guns, for
the traditore batteries, and for sunk ditch defences is required to
be designed on such a scale as will enable these elements to defy,
actively or passively, the attack guns of the day and the morrow.
The same applies to the shelters in which in the case of group
fortification the garrison of the infantry work is placed in readi-
ness to man the parapets, but not necessarily to these parapets
themselves. Further, in proportion as wire replaces the deep
ditch, as an obstacle, heavy and expensive work in peace-time is
dispensed with.

In the system of deployed main armament, on the other hand,
the proportion of permanent work, it would seem, can safely be
much less. With modern artillery means, the sites for counter-
battery armament are rarely obligatory; observation must be
provided for; but the actual position of the guns, and therefore the
line of liaison between observation post and guns, are to a great
extent at least free from limitations of ground. This being so,
the close-defence element of the fortifications may be disposed
to the best advantage for carrying out its task that of protecting
a system of obstacles suitably placed between the battery zone
and the enemy.

In point of permanent work, then, although parts of the bat-
tery positions themselves may occasionally require concrete or
even armour, concealment of virgin earth, and alternative posi-
tions in the great majority of cases afford all necessary protection.
For the close-defence guns, on the other hand the element which
must be able to endure at all costs the chosen positions are
often (if not in most cases) obligatory, and full-scale fighting
protection must be given. Even so, there being by hypothesis
no necessity to develop frontal fire, and the volume of the re-
quired lateral protective fire being relatively little, a permanent
work which is essentially a traditore battery and nothing else can
be both small and well-covered against frontal fire at an expense
much less than that of a great self-contained fort. Its own local
protection may be either a ditch with sunk defences or an in-
fantry system surrounded by wire, but these auxiliaries, too,
would be withdrawn from the crest facing the enemy to positions
on the reverse slope. The only case in which it would be necessary
for any part of the system to go forward to the crest and front
slope would be that in which the artillery observation and com-
mand post is combined with the traditore in one work or one
enclosed group. In such a case the post in question would un-
doubtedly require special treatment as regards its own close-
defence. But all that in principle is necessary is that the post
and its liaisons should be immune.

On the other hand, the security of the main armament against
a rush of hostile infantry was far greater when an obstacle defended
by fire completely surrounded it, and military engineers were very
loth to impair this security. No doubt, when the obstacle cover-
ing the front of the batteries in the deployed order was fully
organized, the latter might be considered safe enough for practical
purposes so long as the interval-defence remained effectively in
action to protect it. But a danger period was foreseen in which
the obstacle was not yet fit to perform its function with cer-
tainty. The " brusque " or (more accurately) the " abbreviated

1 The term " storm-proof," frequently applied to such infantry
works, hardly seems to connote their real function.



attack," proposed by the Bavarian General von Sauer, had
many supporters; and as the tendency already mentioned, of
modern warfare between " armed nations " is to push the line
of resistance as nearly up to the frontier as possible, the fortifica-
tions of that line were in fact exposed to instant attack. 2 Those
of Verdun and Toul were little more than 20 m., the easternmost
fort of Liege only 13 m., from the German frontier, while the
western Metz forts could be bombarded from French soil. In
former days, this would have mattered less, but the growing
mobility of heavy artillery from about 1890 for the first time
made it possible to employ true siege artillery within a few hours
of the opening of hostilities. The attacker, on the other hand,
naturally had to forego some of the powerof hisattacking means
in attempting a coup. His truly mobile siege artillery was limited,
or supposed to be limited, to the calibre of 21 cm. Heavier pieces
though they no longer took weeks or months to arrive in their
emplacements, at any rate took days to do so, and by a sort of
general agreement (to which however there were exceptions)
the situation was met by placing a part of the main armament of
the defence called the safety armament inside a closed ob-
stacle. Usually it was an existing fort that was adapted to house
the safety armament, but sometimes it was included in the design
of a new work. The fort thus in practice reverted partially to its
old duty of serving as a battery position, while in theory its func-
tion had become entirely that of locally protecting a tradilore or
other interval defence. The distinction between property and
accident was no doubt clear to specialists, but the result was
that the generality of armies and peoples continued to look upon
a fort as their fathers had looked upon it, till the astonishing
events of Aug., Sept. and Oct. 1914 so thoroughly undeceived
them too thoroughly, indeed, for in the revulsion, not merely
safety-armament guns but even interval-flanking guns were
removed from closed works.

In the system of group-fortification, it was naturally much
easier to house a safety armament. No element within the ring
of wire need cramp any other, or be drawn into the fighting
activity of another, or suffer from the shells intended for another. 3
Full fighting protection will be necessary, as is always the case
with safety armaments, but, as has been noted above, with more
room the same safety can be given with less expense.

In sum, therefore, the necessity of compromise on this question
of safety armament has caused the dispersed-elements and the
concentrated-elements schools to agree upon: (a) the group or
Feste principle for interval-flanking elements, obstacles and de-
fence of the same, and safety portion of main armament; (b) the
order principle of deployed artillery, with an obstacle covered
by flanking fire, for the remainder of the main armament. This,
it will be noted, leaves a real liberty for the treatment of particu-
lar cases. The proportion of total armament installed as "safety "
is whatever the designer chooses to make it in each instance,
the Feste being adaptable to any proportioning within reasonable
limits fixed by the contour of the ground. A practical check on
enclosing an unnecessarily high proportion will always be the
expense of giving full fighting protection.

Examples of Croup- Fortification. Types of forts, both main
armament forts and others, being described and illustrated in 10.696,

2 To wire a perimeter or frontage of 30 km. to a depth of eight yd.
only requires three eight-hour shifts of (in round numbers) 6,000
workers each, as well as mechanical, animal or human transport
for about 4,000,000 yd. of barbed wire, weighing 300 tons or so,
and 100,000-130,000 stout posts. Other work to be done includes
the clearance of the field of fire, the digging of trenches, the con-
struction of shelters (if not in existence already), opening of com-
munications and liaisons, etc. Land which is occupied by a fort-
ress garrison in war rarely belongs to the Government in peace.

'This can be demonstrated by the "theory of probabilities."
Assume a main-armament cupola 16 ft. in diameter, under accurate
attack by a gun having a probable error of 60 ft. in range and 3 ft.
in line. Calculation shows that this will probably be hit by 7 % of
the shots fired. Now assume a traditore element having a vulnerable
surface on top of 20 ft. from front to rear and 25 ft. laterally. Placed
with its front edge 120 ft. behind the centre of the cupola, this will
receive 3-62% of the shots aimed at the latter. Placed with the
front edge 240 ft. behind, it will be hit by 0-2 % of the shots. In
other words, at twice the distance it is eighteen times as safe.



SIEGECRAFT AND SIEGE WARFARE



475



it is only necessary here to consider examples of the newer group-
fortification. Three forms may be taken, one of which, the Metz
form, has been applied on a large scale, while the others, though
academic examples, are fully representative of principle.

Common to all, it will be seen, are: (a) a wire obstacle round the
whole group, and behind it an infantry trench-position; (b) very
large area, equalling that of town and fortifications together in
some of the old Vauban fortresses, and six to eight times that of
the typical 1873-1903 fort; (c) batteries, closed and under armour,
for the guns of the main armament (or safety armament) irregu-
larly disposed within the wired area.

So far, all are in agreement. But beyond, there are some impor-
tant differences. Thus, the Metz group, and those proposed by
de Mondesir, both possess powerful infantry works with ditches,
whereas the Austrian type lacks this element. Again, de Mondesir
and the Austrian text-books agree in attaching the greatest impor-
tance to the traditore element, remarkably neglected in the Metz
works at least as originally built. Lastly, the Austrian and Ger-
man engineers tend to place the centre of gravity of the artillery,
and even that of the infantry, defence well forward, while the
French author puts them as far back as possible, with only observa-
tories and frontal trenches in the forepart of the area.

The Austrian design (fig. i) as the simplest, is taken first. On the
height 130 is an armoured battery P B, containing four 6-in. howitz-