The amount of work that some of these communication trenches represent is simply incredible. Going up to some trenches in the Ypres salient, I remember, I came across a short patch of road, 200 yards of it at the outside, which was well in view of the enemy and over which shrapnel burst from time to time, whilst bullets skimmed over it the live-long day. To avoid this dangerous area a communication trench had been dug in the fields bordering the road, and threaded its way in and out of the corn and the poppies for fully a mile before it again rejoined the road, which by this had wound out of view of the Germans. In many parts of the line there is a walk of a mile and a half through communication trenches up to the firing-line. All these trenches have to be as deep as a man’s waist, and many as a man’s height. Most of them must have a timber flooring to make them passable in wet weather, and sometimes little bridges have to be constructed to cross the innumerable irrigation ducts and ditches which seam the fertile fields in the region of our army. There must be hundreds of miles of planks in our trenches in Flanders. If you consider that each plank has to be cut and fashioned to fit in its place, after the trench itself has been dug deep enough to be lined, you can form some kind of estimate of the enormous amount of labour which has gone to the welding of our line. As I have trudged down communication trenches behind the regimental guide taking me up to the firing-line, I have often had a sort of mental vision of a vast mountain of energy, as it were, a great sea of sweat and blood, representing the toil and lives expended in the digging of these deep, secure cuttings which are the straight paths leading to the glory of the fighting-line. I do not think it would be going too far to say that these modern trenches are impregnable to direct assault. Indeed, the experience of the war of positions has been to show that neither side can succeed on the offensive unless the trenches have been destroyed, and not always then. Well protected in their deep earthworks, the men with the magazine-rifle and the machine-gun can beat off even such tremendous attacks _en masse_ as the Japanese essayed with success, though at awful cost, in the siege of Port Arthur. As long as the trenches endure they are impregnable. Their impregnability only vanishes when they cease to exist, when they have been destroyed by shell-fire.