Some kind of floor should be provided for the trenches. The simplest and best are made in the following way: Take two seven-inch boards about ten feet in length, nail them together to make a fourteen-inch plank, and then cover the whole with fairly fine chicken wire. Place these boards on the ground with the side on which the wires are joined downwards. They keep the feet from slipping, are easily cleaned by being upended when they are dry, and allow the space under them to be reached easily to pick up scraps of food, etc. There is nothing more heart breaking than having to pursue your weary course for miles, sometimes, up trenches with slippery sides and sloping, wet, treacherous bottoms.
In each trench there must be dugouts for the men to sleep in. The first ones that are made will be very primitive, and will be very much like a fireplace in a room—simply excavations in the back wall of the trench almost on a level with the bottom of it. At first they used to be dug in the front of the trench, but this practice was discontinued as it was found to weaken the power of resistance of the very important parapet. In the course of time more labour can be expended upon the dugouts, and it will be found advisable to construct them of uniform size, six feet long by four feet wide by four feet high. By having them uniform we give the engineers a chance to make frames that can be used to support the roof and the sides and bring them well from the rear to construct the dugouts. These dimensions do not make a very commodious home for four men, but never more than three of a section (of four) are off duty at the same time, and besides there is considerable danger in having large dugouts, as they present a correspondingly larger target for the guns. A direct hit on a large dugout will often bring the whole thing crashing about the ears of the inhabitants. My own adjutant and one of my brother officers were killed by falling beams in large dugouts. The entrance to the dugouts must be kept as small as possible so as to protect the occupants from shells that fall just outside.
The Germans used to follow the custom of digging many of their "funk holes," as they were called, many feet underground. Sometimes they went down twenty and even thirty feet. The idea of this was that they could retreat into these secure places during a bombardment and then emerge with their machine guns as soon as the attacking infantry had started to approach over "No Man's Land." We never followed that custom, for while it will work at times, yet the attacking infantry may be upon you before you are aware of it and have you at their mercy with bayonets and bombs from the parapet. This the Germans have learnt to their cost many times on the Somme.
Many efforts have been made to construct dugouts, reasonably near the surface, that would be shell proof. This is a most difficult matter. It is easy enough to make them shrapnel-proof. A layer of galvanised iron on the roof covered with a foot of loose earth will accomplish this for the velocity of shrapnel is not great. But with high explosive shells it is different. It was seen at Liége and Namur what terrific effects high explosive shells fired from howitzers could have even on re-enforced concrete. I am told that at Port Arthur, a Russian General was killed in a shelter that was covered with over twelve feet of concrete. The closest we can approach to a shell-proof dugout on the field is as follows: Dig an approach trench about ten feet deep, leading into a hole of this depth, by any dimensions you may choose—say six feet square. Put in supports for the roof that shall be four feet from the floor. Roof in with steel rails, such as are used on railroads, then cover them with two or three layers of bricks that have been broken into small pieces. Leave a five-foot air space and then place an exactly similar roof above and cover the whole with earth. Small shells will be stopped at the first set of rails, while large ones may possibly pierce them. But the effect of the explosion will mostly be taken up in the airchamber and the dugout itself protected. The reader will readily perceive the difficulty of constructing such dugout on the field and they can certainly not be provided for the accommodation of the common soldier however precious his life may be.
As the days go by, every effort must be made to improve the trenches. This can be done in many ways, some of which will be obvious. The front line is, of course, the most important one, and the greatest amount of work has to be done there. But support and reserve lines as well must be constructed and many communicating trenches. Support lines were usually dug at a distance of thirty to eighty yards from the firing line. In them we kept a few men to be used in case of emergency. This line was an exact duplicate of the front line and was intended to be used in case we were pushed back. The reserve line was about five to eight hundred yards back from the front line and was not brought to any very great degree of completion. Interspersed between these three lines were many redoubts, or especially strong points containing machine guns, etc., whose defenders were expected to hold on to the very last and take advantage of their more secure position to make the attacker pay dearly for his advance. All these lines had to be linked up by communicating trenches, which started about a mile in the rear of the front line and went up in zigzag lines to the latter position, crossing the other trenches on their way. These communicating trenches are used for the purpose of bringing up troops and supplies, etc., and for taking to the rear the men that have been wounded. It is usually arranged to have some of these trenches "Up" and some of them "Down" roads. Each line of trenches (except of course the "communicating") contain dugouts for the use of the troops that hold them. The distance between the communicating trenches varies from twenty-five yards to three or four hundred according to the state of perfection of the trench system.
For special weapons such as machine guns and bomb guns, special shelters have to be made. Extra strong parapets are provided as well as head cover of railroad ties, and every effort is made to keep the exact position of the machine guns secret from the enemy. We soon learnt that he was very anxious to find our machine guns and would shell us liberally in the hope of being able to locate them.
Care must be given to the question of drainage. Small ditches should be dug at intervals of a few yards to lead the water to pits in the rear. In Flanders, where we were very near river level, we installed hand and power pumps to keep the water from taking possession of the trenches. Even then, on rainy days we sometimes were in water up to our waists.
Great care must also be taken in the construction of latrines. The method that was followed was to dig a short "blind alley" trench at right angles to one of the communicating trenches, and at a distance of twelve or fifteen yards from the front line. Starting from the end of this blind alley, the trench was gradually filled in with earth as it was used. In other cases biscuit tins were used as receptacles and the ordinary sanitary squads emptied them at specified times into a fairly deep pit. These latrines should be well protected with sandbags to keep the enemy from finding them and training a machine gun on them, in the knowledge that they were very likely to get some of the men who used them during the day.
This, I believe, gives the principal points in the construction of the trenches. Men should be taught to dig them in broad daylight at first and then when they have learnt the knack, they should be set to dig them at night. From time to time during their training they should be made to return—preferably to the same sections of the trenches—to improve them and maintain them. An excellent scheme is to arrange competitions among the men to spur them on to invent ingenious devices for protecting themselves and their fellows during their occupation of them. At certain times they should also be made to spend a night and then several nights there, going through the regular routine of sentry duty, stand to arms, etc., just as they will have to do in real warfare. Another scheme is to choose opposing sides with trenches within easy reach, say, twenty-five yards apart. Arrange a three-day tour of the trenches, and let each side attempt to surprise the other. Umpires can be stationed in No Man's Land to decide as to the relative merits of the two sides. At certain times, additional interest can be given to the conflict by some harmless missiles such as sand bags (without the sand!) rolled up and made into a ball the size of a base ball with string. These will also give excellent practice in bomb throwing.
The rules of the trenches can be summed up in a few words: "Keep your spirits up and your head down."