CHAPTER III

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.

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.

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.

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.

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.

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).

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.

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_).

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.