TRENCH ORGANIZATION
1. General remarks.
2. General plan of an intrenchment system. Trenches. First and
second lines. Trenches of attack. Artillery. Wires.
3. Mines and counter-mines.
4. Special railway troops. Transportation by roads.
5. General remarks on transportation.
6. Camouflage.
=1. General Remarks.= When her dream of a short war which was to
realize all her aims of conquest was dissipated, Germany resorted to a
policy of occupation in the hope of either maintaining her hold upon
the territory she had seized, or else of eventually using it as an
asset in negotiations for peace. At the end of 1914 she occupied nearly
the whole area of seven French Departments, three or four of which are
among the richest agricultural and industrial districts of France.
To attain her ends, Germany intrenched her armies on the nearest front
that she had time to occupy, one of several defensive lines which she
had selected long before. Her spies, in time of peace, had furnished
her with accurate knowledge of all the important positions.
Thus, when the German armies of the first line were beaten on the
Marne, and fell back in disorder, they found, at a distance of three
or four days’ march, beyond Soissons, on the frontier of Lorraine, an
unbroken line of intrenchments already organized by the second-line
troops while they were operating their enforced retreat.
The French pursuing armies had not, in September, 1914, the material
means of assaulting the enemy’s intrenchments. They had just fought
a series of battles which had considerably lessened their effective
forces. Their regiments had to be officered anew. They had no
alternative but to intrench themselves, on positions as little
disadvantageous as possible, in front of the enemy. Thus all along a
line extending from the North Sea, at Nieuport, to the frontier of
Switzerland, began the formidable conflict which is still raging.
The distance between the two hostile fronts varies from 30 or 40 metres
to 1200 or 1500 metres at most.
After big attacks, prepared by long bombardments, the first lines cease
to exist, and very often both of the hostile fronts are merged into one
another. The most advanced small outposts have no other shelter than
that of shell-craters, and it is by means of grenades thrown from one
crater to another, and with whatever earthworks can be improvised with
the tools on hand, that attempts to rectify the fronts are made.
Both parties, most of the time, have three successive lines of
organized defence, and sometimes more.
It is to be noted, however, that while the Germans have adhered to
the three-line principle in the sectors where they believe themselves
but slightly threatened, on the fronts where they are heavily pressed
by the Allied Armies, they have organized, as their advanced lines
weakened or were forced, a series of very strong positions, one behind
the other. It is impossible to be precise as to the number of these
lines. According to the reports of the aviators, several complete
systems of defences exist between the positions they are now defending
and the Meuse.
It is interesting to remark that the multiplication of large-calibre
artillery has caused changes to be made by both belligerents in the
construction of shelters and intrenchments.
During the winter of 1914–1915, no serious bombardments took place
before April. Both sides organized themselves on their positions,
excavating shallow shelters which were braced with wooden beams and
roofed with two or three layers of logs, over which earth was more or
less thickly packed. Such shelters resisted well enough 150 mm. shells.
But, in 1917, during the operations in Artois and Champagne, the
adoption of larger calibres, and the use of torpedoes fired by trench
machines, compelled the belligerents to bury themselves more deeply
in the ground, wherever the soil permitted, and to build more solid
shelters. When water interfered with deep excavations, the shelters
were covered in with very strong T-shaped iron railway ties, or with
several layers of steel rails; but these proved insufficient, and the
Germans were the first to construct those bombproofs of reinforced
concrete which the British for the first time encountered on the Somme.
The concrete blocks are very large and the steel reinforcing bars
extremely strong. Such works certainly impede and delay the operations
of the enemy, especially when they are extensively employed, but
events have proved that, given time, they can always be destroyed by
gun-fire. The French have constructed similar works only at points
of capital importance. They prefer the old wooden shelters, well
reinforced with earth.
[Illustration: Ailles and its western approach
February 10, 1917--2.30 P.M.]
At all the inhabited places in their lines, and at points of natural
strength, the Germans have organized independent centres of resistance.
They have transformed whole villages into fortresses. Mention need
only be made of the labyrinth of Carency-Thiepval, Beaumont-Hamel, the
tunnels of Cornillet, of Hill 304, of Mort-Homme, etc.
In every one of those places a surprising number of concrete
constructions and superimposed subterranean galleries were discovered.
In them the enemy had collected reserve troops, food, and munitions.
Such shelters, no doubt, afforded the Germans great protection, and in
order to destroy them, it was necessary to have recourse to more and
more powerful methods.
An officer of the 81st Regiment of Infantry which captured Mort-Homme
writes as follows: “ ... and on the hill where the 81st Regiment is
encamped, what an accumulation of defensive agencies! Wire, tunnels,
trenches, observatories, shelters of every description, machine-gun
posts, light cannon, nothing is lacking. To these ordinary means of
defence, other extraordinary ones had been added, consisting of three
immense and very deep subterranean systems (82 steps led down to
one and the length of another exceeded one kilometre) provided with
ventilators, Decauville narrow-gauge railways, electricity, posts of
command and relief, rooms for the men, and stores for food, arms,
munitions, and material. All these extraordinary fortifications could
not resist the impetuous assault of our troops, which had been preceded
by a six-day bombardment so intense that the entire first line was
enveloped in a thick cloud of smoke about two hundred metres high, and
the ground shook all the time.”
In fact, no absolutely impregnable shelter has yet been devised,
and the story of fortification is but a repetition of the story of
defensive naval armament. The thicker the plates of the dreadnoughts,
the more powerful the guns are made, and the guns have the last word.
Moreover, it has been by no means demonstrated that the German
intrenchments, which have cost enormous sums, and an amount of human
labour that the Allies would have been unable to furnish, have to any
extent reduced the enemy’s losses. On the contrary, it appears that the
temporary protection afforded by such works is more than offset by the
great losses in men and material which is the result of their final
destruction.
The official reports which reach us, just before going to press, of
the French victory of the 23d-25th of October, 1917, on the Aisne,
prove that, in the captured salient (which the Germans had considered
of capital importance), they had accumulated means of defence more
considerable and powerful than at any point hitherto conquered.
At the inhabited points, they had converted all the cellars of the
houses into bombproofs. They had bored tunnels of communication,
some of which were a mile long. Everywhere they had built formidable
concrete dugouts connected by covered passages loopholed for
machine-guns, and had even mounted heavy pieces of artillery in their
first lines. The whole position was considered so impregnable that they
had stored in its subterranean spaces a very large quantity of winter
supplies. The topography of the region was unusually favourable to the
construction of defensive works, and a number of natural grottoes had
been turned to good account.
In a few days a powerful artillery had enabled a heroic infantry
(fighting under the eye of the American General Pershing) to overcome
the resistance of an enemy defending his ground with a force of about
nine divisions. This operation justifies once more our assertion that
it is impossible to construct works that are absolutely impregnable to
gun-fire.
To give an idea of the morale of the French, we can do no better than
to cite a passage from a letter, written at the Front on October 6th,
which we have just received from a young artillery officer. “Watch the
communiqués that will be issued on or about the 20th day of October.
We are preparing for the Boches a song and dance that they will not
forget.”
=2. General plan of an intrenchment system.= The description we give
hereafter of the organization of the lines is, of course, like the
following diagram, purely explanatory and illustrative.
[Illustration: South-east of Ailles
February 10, 1917--2.30 P.M.]
It is intended to set forth the principles governing
trench-construction and to give a general idea of a system of field
fortifications. Such a system is subject to the exigencies of local
topography, and it is therefore impossible to state exact measurements
and distances for the broad outlines of the plan.
Thus one could formulate no law to fix the distance which should
separate the different lines of an intrenched position; and even with
regard to the breadth of the interval between two trenches of the same
line, one can scarcely be more precise; since, however essential it may
be in theory to make it broad enough to prevent a single shell from
doing damage to both trenches, in practice the configuration of the
ground does not always permit of such a precaution.
The plotting-out of the trenches is of very great importance. They must
be made in such a manner that they will not be exposed to an enfilading
fire of the enemy’s guns, and will be strong enough to oppose the
greatest resistance to attack.
Too long and too straight lines are generally avoided. The usual custom
is to reproduce the ground plan of a bastion, with alternating salients
and re-entrants, a disposition which permits flank firing across the
front of the trench (Fig. 1).
The re-entrants are frequently additionally fortified so as to render
them insurmountable to assault, so that the defenders need occupy the
salients only. Advanced trenches exposed to intense bombardment can
thus be defended with a smaller number of men.
[Illustration: _FIG. 1_]
The inside of the trenches is provided at short intervals with
_pare-éclats_, or shell-screens, consisting of buttresses of earth
supported by _clayonnages_, or wattle-work, which are intended to limit
as much as possible the radius of action of a bursting shell to a
single section of trench (Fig. 2).
The trenches are of different dimensions; nevertheless, when time
is not limited for their construction, Fig. 3 can be considered as
representing the most generally adopted type. The earth thrown up in
front, either loose or filled into sandbags, forms the parapet.
As the action of the weather, especially rain, tends to cave in the
sides of the trenches, they have to be upheld with wooden props, or
with wire nets, supported at three or four metre intervals by wooden
or iron posts.
[Illustration: _FIG. 2_]
[Illustration: _FIG. 3_]
In the very damp regions small drains (_rigoles_) and cesspools have
to be dug to carry off the water, and the trenches themselves must be
provided with open “boardwalk” flooring. When not pressed by time
and scarcity of material, especially in winter, all possible means
should be adopted to prevent the men from standing too long in water.
Dampness, more than cold, is responsible for frostbitten limbs.
[Illustration: _FIG. 4_]
In the parapets of trenches that are expected to last some time,
loopholes are made by inserting pieces of sheet-steel with openings to
allow the passage of a gun barrel. Each opening closes with a small
door which remains shut except when the loophole is in use (Fig. 4).
[Illustration: South-east of La Bovelle Farm
February 10, 1917--2.30 P.M.]
When neither time nor material is lacking, the machine-gun shelters
(Fig. 5) in the trenches are installed within steel cupolas, which are
either stationary or revolving. The mechanism of the latter is,
however, complicated, and too delicate for use in the first lines.
These cupolas are also much used for observation posts, and, as we
shall see later, they are kept as much as possible concealed from the
sight of the enemy by camouflage.
[Illustration: _FIG. 5_]
The first line comprises three positions or trenches. That nearest to
the enemy is the advanced trench, and at a short distance behind it are
the support trenches. Only a few men are now posted as sentries in the
advanced trenches. In front of these trenches, “listening” or “watch”
posts are hidden in the ground. Between these posts and the advanced
trenches barbed wire entanglements are stretched, in number and width
proportionate to the dangers threatening the position.
In the support trenches are the dugouts sheltering the men against the
fire of the artillery. Many communication trenches or _boyaux_ connect
them with the advanced trenches, facilitating the rapid occupation
of the latter in case of need. In the advanced trenches are built
shelters for the machine-guns. Rifle-fire is directed through loopholes
protected by the steel plates above mentioned (Fig. 4) which are
bullet-proof at fifty yards.
At some distance to the rear of the support trenches and overlooking
them, the first-line system is reinforced by a line of “centres of
resistance,” which is punctuated with blockhouses protected by thick
wire entanglements. Well sheltered machine-guns, a certain number
of which sweep the communication-ways leading to the front, compose
their main armament. This blockhouse line is connected by many
communication-ways with the trenches in front of it.
These centres of resistance are intended to check the advance of the
enemy, when they succeed in breaking into the three anterior lines, and
to give the reserves time for counter-attacking.
Between the blockhouses and the second-line system a fortified line
is frequently organized which is called the “protecting line of
the artillery.” This is intended to repel the advance of the enemy
infantry, if they gain possession of the first-line system, before they
reach the field batteries, or to retard it long enough to allow the
batteries to fall back. This line is held by the troops of the sector
which do not belong to the fighting contingent.
The distance from the first-line system of trenches to the second-line
system varies according to the configuration of the ground. These
second lines should, when possible, overlook the first lines, so as to
hold them under their fire. The same rules prevail in the location of
the third lines. In the sectors which seem to particularly interest the
enemy, very strong “check positions” are prepared in the rear.
The troops occupying the second and third lines should be protected
against bombardment as much as possible. It is therefore in these
trenches or very near them that shelters capable of withstanding heavy
gun-fire should be constructed.
We say “in or near” advisedly, for it is important to hide the shelters
as much as possible from the enemy, and, to effect this, it is no
inconvenience to build them a little in the rear of the trench-lines,
if the desired result can thus be obtained. Often it will be necessary
to do this merely for the purpose of getting more favourable ground on
which to erect the shelter.
The main point to emphasize is that these shelters should be connected
by means of communication-ways permitting quick passage from the
shelters to the trench-lines.
In all three lines, when the ground is suitable, observation posts are
located, but however well they may be concealed, the enemy is not long
in discovering them, and in the first line it is generally with the aid
of different kinds of periscopes that the observations are made.
COMMUNICATION LINES. All the trenches are connected by communication
trenches or _boyaux_, which conceal from the enemy the movements
of troops. These are mere ditches about two yards deep, the earth
from which is thrown out to the left and right, or on one side only.
They follow a zigzag line so as not to be exposed to enfilading
fire, or, when straight, are protected at intervals by earth screens
(_pare-éclats_).
[Illustration: Diagram of Campaign Intrenchments.]
The depth or breadth of these “ditches” depends on the use to be made
of them. For instance, those intended for carrying out the wounded
must be deep and wide.
To preclude obstruction during attack, and to provide free and quick
passage for reserves rushing up from the rear, communication trenches
should be very numerous. Some should be designated for forward and
some for rearward movement. Each one should bear a name or a number
and at its extremities arrows should indicate the direction of the
circulation. Thus confusion will be avoided.
TRENCHES OF ATTACK. When the opposing lines are sufficiently far from
one another, it is impossible to launch an attack without having
brought the infantry within striking distance.
For this purpose a sufficient number of _boyaux_ are dug in the
direction of the enemy, starting from the advanced trenches, passing
under the wire entanglements, and connecting together with a
cross-trench when at the required distance. This is the “trench of
attack” and at the proper time, steps are made in it to facilitate the
egress of the troops at the moment of assault.
This work is done at night, and preferably, when possible, by troops
which are not to take part in the attack. The men proceed to this work
under cover and patrol guard.
ARTILLERY. The artillery, according to its size, is placed between the
lines or behind them. Field batteries are pushed forward up to the
“artillery protecting line” and placed in position to shell, at any
time, certain designated portions of the enemy’s front. They are either
buried in the ground or sheltered under casemates, when the latter can
be concealed from the enemy.
The trench-guns are, generally, on account of their small range, placed
in the first-line support trenches.
The heavy artillery, farthest back of all, is drawn up in echelons
according to its size and the part assigned to each part of it.
WIRE ENTANGLEMENTS. The width of the wire entanglements varies
considerably. Well-strung wire prevents any attack, and none can be
attempted until the entanglements are destroyed. In front of their new
lines on the Aisne, where the Germans are simply holding the ground,
and have given up all notion of advance, they have stretched eight or
nine successive rows of wire, each row being fifty metres wide.
Wherever defence only is contemplated, the protection of wire
is essential, but it will be well to bear in mind that too many
entanglements may prove inconvenient at the time of an attack. We
have seen that in such cases, the difficulty is solved by digging
communication trenches under the wires.
=3. Mines and counter-mines.= Since both parties dug themselves in,
much use has been made of mines and counter-mines, especially in 1915
and a part of 1916.
The aim of the mine is to throw the enemy into sudden consternation
and disorder, while destroying an advanced trench, or work. The French
considered the mine as a weapon with which it would be possible to
remedy at certain points the defects of their line.
They caused heavy losses to both parties, but are not so much used
now for the very good reason that, where the fronts have undergone
no change since 1914, the soil has been so greatly disturbed that it
would be absolutely impossible to make the necessary excavations. We
shall simply recall that in June, 1917, the British, prior to their
attack on Messines, set off twenty mines, each containing twenty-three
thousand kilograms of explosive, and as the Germans were not aware
of their construction, the effect of the explosions was terrible,
producing huge craters, seventy metres deep and several hundred metres
in circumference.
Mines are dug by hand or electric drills. The latter have the
disadvantage of making too much noise. Greatly improved systems
of “listening posts” permit the enemy’s operations to be detected
and opposed, and in all cases, excepting at Messines, where the
British bored their galleries at more than fifty metres underground,
mine-digging was carried on under great difficulties.
The best means to neutralize the danger of a mine whose construction
is discovered, is to reach it as quickly as possible by excavating a
“counter-mine,” and blow it up before the enemy has a chance to set
it off. The success of such a counter-mine is termed a _camouflet_
inflicted on the enemy.
In our opinion, mines and counter-mines will play a less and less
important part in the present war, but it will nevertheless be
necessary for our armies to be provided with the means of operating
them whenever the Command may deem them advisable.
=4. Special railway troops.--Transportation by roads.= Since the
beginning of the war, France has been lacking in special technical
corps, especially for the railways. Her ante-bellum system was
insufficient to cope with the rapid development of the military
operations, and the reorganization rendered necessary by trench warfare
along an extensive front.
A large proportion of the railroad employees was at first mobilized to
assist and reinforce the railway troops. Then, after a few months, a
large number of these men had to be sent back to their former civilian
duties, in order to assure the economical life of the country.
While the transport of troops alone requires a daily extension of our
road and railway systems, and constant attention to repair-work in
the fighting zones, the industrial efforts of the nation to equip and
arm the millions of combatants also necessitates an enormous railroad
activity. As the lack of workmen prevents locomotives and carriages
from being repaired, and the supply of rolling-stock shipped from
America is not sufficient, it is as much as the French can do to keep
their railroad tracks in good condition.
It should be noted that owing to the intense and forced use of her
interior lines to which we have already referred, the railways of
Germany are in still worse condition than those of France. For want of
oil and grease a large portion of their rolling-stock cannot be used.
To make up the deficiency in technical troops, France has had to have
recourse to her “territorial units,” composed of men unfit for the
Front and generally more than forty-five years old, who, exhausted by
three years of war, are unable to do much work.
This short résumé of the conditions prevailing on the rear of the
French Front will enable the Americans to comprehend the necessity for
organizing on a very extensive scale a special railroad transportation
corps. Without interfering with traffic on the principal roads
of the United States, it should be possible to create railway
regiments officered by civil engineers, with separate units for
track-construction, operation of trains, and repair of rolling-stock.
The engineer regiments should likewise be enabled to build rapidly
field-barracks of all kinds in the zones devastated and abandoned by
the Germans.
They should, moreover, be entrusted with the erection of hospital and
ambulance buildings, and their removal and reconstruction whenever new
ground is wrested from the enemy.
TRANSPORTATION BY ROAD. Except in the immediate vicinity of the lines,
where horses are still used by the regiments for transportation between
the camps and cantonments and the bases of supply, all the conveyance
of men and material, which is not made by rail, is done by motor-cars,
in daily increasing numbers.
Not only have the railways from the rear to the front been increased
in number, but also the communication lines running parallel with the
front. Their capacity, however, being inadequate for moving large units
quickly from one part of the Front to another, motor-cars should be on
hand in number sufficient for the rapid transportation of an entire
army corps.
There should be a permanent service of motor-cars between the front
lines and the rear, to assume the task of taking fresh troops to the
line and exhausted troops to the camping-grounds. They can be used
also, and with great efficiency, when circumstances at the Front
require the prompt advance of reserves from the various bases.
We shall see later how motor-cars are used for the supply of food or
ammunition. Many more cars are needed for the hospitals, ambulances,
and the carrying of the wounded.
The consumption of gasoline, notwithstanding the suppression of the
abuses which were for a long time prevalent on the Anglo-French Front,
remains considerable. France is supplied with it exclusively by the
United States and Mexico.
=5. General remarks on transportation.= The question of supplies of all
sorts will be one of the difficulties connected with the organization
of the American Armies on French soil. The United States will not
merely have to convey troops from one continent to the other, but also
to ship all that is necessary for the subsistence of her armies, their
upkeep, their armament, their artillery, etc., just as if they were
expected to land in a desert country where the barest necessaries of
life would be lacking.
The American Government and the General-in-Chief have from the start
been aware of the difficulties awaiting them, and, immediately after
the landing of the first troops, very important works were begun for
the improvement of the French ports of landing and for the duplication
of French railroads, wherever needed. This work is being actively
carried out under the direction of American engineers.
=6. Camouflage.= Everything pertaining to the equipment and employment
of troops must be hidden, so far as possible, from the sight of enemy
aviators, and the various devices resorted to for this purpose are
termed “Camouflage” (disguise).
Artillery, transportation parks, ammunition dumps, camps, roads of
communication, etc., are masked in many ways, on the general principle
of causing the object to be concealed to blend with the tint of the
soil or the foliage, or to melt into the landscape and avoid the eye.
Coverings of brushwood or straw represent the simpler, and framework
supporting artificial greenery or painted canvas, the more ambitious
forms of camouflage. Objects irregularly blotched with paint of
different colours are practically invisible at a certain distance--a
device borrowed from the “protective colouring” of the animal kingdom.
Batteries of dummy guns are often used in this, as in former wars, to
deceive the enemy.
It is highly important to have good points of observation within the
first lines, whence the enemy’s defences may be searched with powerful
field-glasses. To meet this need, artificial trees, rocks, etc., have
been provided when nature failed to supply them.
The camouflage of the French army has been entrusted to a special corps
of professional artists, which has proved a most useful unit, since it
is necessary that the work done should deceive not only the human eye,
but the sensitive plate of the camera.