Without fear of being accused of exaggeration, we may, therefore, reckon the total length of the trenches which the Belgian Army had to make, as 10 to 15 times that of the front itself. To this we must add the many kilometres of communication trenches which allow the men to move from one line to another without being seen and to a certain extent without being hit by the enemy.
At a low estimate the total work amounts to at least 400 kilometres of earthworks[B]—the distance, as the crow flies, from Paris to Cologne or from Paris to Strassburg, or half as much again as that from Ostend to Arlon, the longest stretch which can be measured in Belgium.
The accompanying photographs show several views of the trenches of the Belgian front on the Yser, and give a better idea than any words of the real convict work accomplished during three years of incessant labour in horribly difficult ground. Just think what it involved! Every yard of fire-trench—traverses and parados included—required the moving of 7 to 8 cubic metres of earth; every yard of communication trench, the transport and placing of at least 4 cubic metres. You will not be far out if you reckon at 39½ million cubic metres (49-2/3; million cubic yards) the volume of the earthworks raised on the Belgian front in the construction of the main and communication trenches alone.
Trenches of both classes are either formed entirely of sand-bags or very solidly revetted with sand-bags, wattles or bricks. All these materials have had to be laboriously brought up from the rear. We mention this fact again, as it cannot be over-emphasised. The total number of bags used runs into tens of millions, while the superficial area of the hurdles placed in position must be reckoned in thousands of square yards.
But the mere making of the trenches is not the whole business. They must be protected from attack by means of a dense and deep system of auxiliary defences—networks of barbed wire, chevaux de frise, land mines, etc. What statistician could calculate the number of the hundreds of thousands of stakes that have been driven and the thousands of miles of wire arranged in front of the parapets by our heroic workers?
Wherever our lines are near those of the enemy—who as a rule possesses the great advantage of commanding them—special works are needed to prevent bullets enfilading the trenches and doing havoc. All these trenches are, therefore, covered with a series of arches, which may be seen in some of our photographs. The soft bottoms of the whole system of defences must also be carefully consolidated to render their occupation possible and to enable the men to move about with ease. Duckboards, assembled just behind the front and then brought into the lines, have had to be laid everywhere with infinite labour in the muddy bottom of the trenches—dozens of miles of them—and relaid heaven only knows how often!
It would be a good thing if one could regard the works when once carried through as definitely finished; but that would be too much to hope for, since the most solid revetments crumble in sorry fashion under bombardment, and the elements also seem to be bent on destroying them. Anything heavy settles little by little, owing to the lack of consistency in the subsoil. In bad weather especially, when the rain never ceases and the floods spread, our men daily report parapets giving way and duckboards disappearing under the water or mud. Then everything has to be done over again. One must set to work, with a patience ever sorely tried, to reconstruct laboriously what was originally put together only by the most strenuous efforts. Thus it has come about that many of the trenches have had to be reformed five or six times.
So far we have dealt only with the main positions. We turn now to the prodigious effort demanded by the construction of advanced fortifications right in the middle of the floods. The first step is to make foot-bridges, several kilometres long in some places. (One of our photographs gives a striking view of such a bridge.) Over these, which the enemy can sweep with his fire, all the materials needed for making the advanced works must be carried, usually on men's backs and in any case by very precarious means of transport. A mere "water-post" requires thousands of sand-bags, so you can form some idea of the labour implied in the building of one of the many important posts situated in the inundated area to protect our main positions. All the earthworks, reckoned in hundreds of cubic yards; all the concrete emplacements which alone are able to withstand the continual bombardment; all the close networks of barbed wire have had to materialise but a few yards away from the enemy's lines. You may well ask yourself whence the men have drawn the reserves of perseverance, energy and pluck that were needed in such conditions for raising fortifications like these above the waters.
(c) Various Engineering Works.