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 3½ _million cubic metres_ (4-2/3 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!