But, if the defence was overwhelmed by superior numbers, it seems clear that it broke down earlier than it need have done, and that the fault lay in its organization. The Forward Zone was little more than a screen, and was so regarded. Yet it was held by three whole battalions on the front of each Division. The orders were that the enclosed keeps, even in the front system, were to resist to the last. The whole position in front of the Battle Zone may be regarded as the outpost line. This outpost line, manned by a third of the infantry force of each Division, was not to retire and was not to be reinforced. The first shock of the attack swept this third away. It was defence in detail, not defence in depth, and in detail it was defeated. Defence in depth may be defined as successive lines of organized defence, upon which the defenders can fall back in succession, always finding some fresh troops on the new position, so that the line becomes gradually stronger as it falls back, until at last is reached the line upon which the real defence is to be made. Gallantly as they strove, much as they accomplished, the three battalions in the Forward Zone of the 36th Division were wasted under the Fifth Army scheme. As for the lines of the St. Quentin and Somme Canals, which might have been very formidable, there had been no preliminary organization of their defence, nor even reconnaissance with that end in view. When the moment came the defence had to be improvised. [Illustration: Map VI. The Retreat of March, 1918.] This does not detract from, but rather increases, the magnificence of the defence of the 36th Division, and indeed of the whole of the XVIII. Corps, which had sixteen German Divisions, in front and second line, against its four. There is at least every reason to suppose that, had all gone elsewhere as on the front of the XVIII. Corps, the full weight of reinforcements would have arrived before the enemy had forced the lines of the St. Quentin and Somme Canals. In that case the war would undoubtedly have had a speedier ending. FOOTNOTES: [52] These men were evidently advancing from Saulchoy-sur-Davenescourt, into which a number of the enemy had filtered in the darkness. [53] Returned prisoners of war informed Captain Miller, whose diary has been drawn upon in this chapter, that the streets of Erches, through which they were marched, were littered with German dead. So, as he remarks in a letter to the writer, the affair "was not so one-sided as it looked." CHAPTER XII FLANDERS: THE 108TH BRIGADE IN THE MESSINES-KEMMEL BATTLE:[54] APRIL TO JUNE 1918