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.

Most of the works already referred to were carried out either entirely or chiefly by the infantry, who, after hours of guard duty in the trenches, laid aside the rifle only to pick up a tool and indefatigably continue their rough and dangerous labour among the same scenes of ruin and devastation.

We have remarked in passing that much detail work of widely different kinds has had to go forward simultaneously with the organisation proper of the defensive positions. Its execution was entrusted to special troops; engineers (sappers), bridge-builders, telegraphists, railway corps, etc., as well as to many labour companies consisting of men of the older classes attached to the engineers. Men of the heavy and field artillery have had to make the many emplacements for batteries of all calibres, which have increased steadily in number as the Belgian Army has been able to get and assemble in its workshops an abundance of the requisite material. It is impossible to describe the innumerable works of this kind in detail without straying too far, so we will content ourselves here with reviewing them briefly and giving some figures which will enable the reader to appreciate the great responsibilities assumed by the various branches.

1. Concrete Shelters, Redoubts and Fighting-Posts.—The weakness of earthworks constructed with sand-bags, which are scattered in all directions by bursting shells, has compelled us to build numerous concrete shelters, though the work is beset by many difficulties and sometimes has to be executed right under the enemy's nose—bombproofs, machine-gun posts and fighting-posts for the battalion, regimental and battery staffs. All construction of this kind must be preceded by a thorough consolidation of the ground, which in its natural condition is too soft to support such heavy weights. At several points in the front lines themselves we have also had to make particularly strong points d'appui, usually concrete redoubts, in which a large garrison may hold out to the last man.

The importance of these works will be inferred from the statement that their construction has involved the use of at least 300,000 to 400,000 cubic yards of concrete.

2. Communications.—It will be remembered that the district occupied by the Belgian Army was poorly supplied with railways, roads and usable tracks. After the battle of Flanders (October to November, 1914) the continuous movement of troops over the existing roads, added to the effects of bombardment and bad weather, had done great damage to almost all the few available means of communication. This state of things had to be promptly remedied, both to accelerate putting the sector into a state of defence and, what was still more urgent, to enable all kinds of supplies required by the troops and the materials for the defence works to be brought up.

Special units, therefore, laid in the advanced army zone some 180 kilometres of new railways of standard gauge, and several hundred kilometres of Decauville railway. The light tracks were gradually pushed through the communication and main trenches, and even along the foot-bridges leading to the main pickets.

So that our men might cross the countless canals, streams and ditches met with everywhere, and move over flooded and marshy areas, the Belgian engineers built hundreds of bridges and thousands of culverts, besides some tens of kilometres of the foot-bridges already described. As an example, we may mention that one of these foot-bridges, crossing a marsh in the southern part of the front, is quite 800 metres long.

As for the road-system, existing roads had to be remade and improved, while new ones were built and narrow ones widened and strengthened sufficiently to carry all kinds of traffic. This road-building and mending was applied to 400 kilometres of roads and usable tracks in all; and absorbed some 500,000 tons of road metal and as many tons of sand—which involved the moving and handling of, say, 1,000,000,000 tons of various materials.

The upkeep of the roads, which carry a dense and continuous traffic, demands unceasing labour, especially in the winter.

In conclusion, we should mention that there are, in addition to the road-system properly so-called, many infantry routes and approaches for artillery which have had to be made