From what you have read in the former volumes you know that the German theory was right, and that the French theory was wrong. Liége, Namur, Maubeuge, and Antwerp all fell before the high explosive shells of the huge howitzers in an astonishingly brief time. Verdun did not fall, it is true, but this was because the French turned it into a new type of fortress altogether. They made field works at a considerable distance from the old forts, and moved out the heavy guns to advanced trenches. Rails were laid down so that as soon as the guns were "spotted" they could be moved to new positions at short notice. Thus, as I told you on page 280 of Volume II., instead of fixed forts, each, say, mounted with ten heavy guns, these same ten guns were "dotted here and there in trenches rapidly established in one place and another, along perhaps half a mile of wooded vale, and free to operate, when they moved, over perhaps double that front." This is the German theory of fortification, and Verdun was saved because the French adopted it. Another theory of the German Staff was that high explosive shells could be used with great effect not only against fortresses but against troops in the field. In former wars shrapnel[4] was largely used, but in the present war the Germans believed that high explosive shells would be more effective.[5] Modern armies, as you know, "dig themselves in" whenever they can, and fight from trenches. Against troops in deep trenches with good head-cover shrapnel is not very deadly. When trenches have been occupied for some time they become little fortresses, with strong parapets and entanglements of barbed wire in front of them. Before sending infantry to attack such trenches, the Germans determined to fire high explosive shells at them, so that the barbed wire would be torn away, the parapets of the trenches would be blown in, and the defensive works destroyed. In this respect, too, the German theory proved correct, and when the trench warfare began in real earnest the Allies had to follow the German example. Months passed, however, before their supply of howitzers and high explosive shells was sufficient to enable them to cope with the Germans on equal terms. [Illustration: The Effect of Shrapnel on Trenches. Some four hundred to five hundred balls and splinters spread forwards, downwards, and fan-wise when the shell bursts. (_By permission of The Sphere._)]