By midsummer the lines on both sides of the western front were an elaborate series of field fortifications. The shallow trenches of the preceding fall were practically things of the past. And these fortifications extended from the Vosges to the North Sea. They naturally varied with the nature of the region in which they were built. The marshy character of the soil along the Yser and about the Ypres salient made it impossible to go down very deep. Hence it was necessary to build up parapets which were easy marks for the artillery. The Germans had the better places on the higher levels from Ypres to Armentieres; but the British line opposing them showed remarkable engineering skill. The advances of the Allies had resulted in making the first line of trenches somewhat temporary in character in the sections about Festubert, La Bassee, and the Artois; but in these regions there were strong fortifications in the rear of both lines. The condition of the ground from Arras to Compiegne was excellent for fortification purposes. The Teutons had the better position in the chalky region along the Aisne, though the chalk formation did not add to the comfort of the men. In the northern part of Champagne trench life was more bearable. The forests in the Argonne, the Woevre, and the Vosges made the trenches the best of all on the western front. The greater part of these so-called trenches, the like of which had never before been constructed, could not be taken without a bombardment by heavy artillery. And, in the rear of each line there was a series of other fortifications quite as impregnable. This condition was a gradual growth which had developed as a result of the increasingly new methods of attack. As new means of taking life were invented, new means of protection came into existence, until, for the present, the inventive genius of man seemed to be at a standstill. But all this activity and preparation at the front meant a greater activity in the rear of the opposing lines. Fighting men were a necessity; but, under existing conditions of warfare, they were useless unless they were kept supplied by an army of artisans and another army of men to transport munitions to the soldiers on the firing line. In fact it was being forced on the minds of the commanding officers that the war could be won in the workshop and laboratory rather than on the battle field. CHAPTER XXVI BELGO-GERMAN OPERATIONS