There lie before me a Memorandum, by an officer of the General Staff, on the Hindenburg line, drawn up about a month after the capture of the main section of it, and also a German report, made by a German officer in the spring of 1917. The great fortified system, as it subsequently became, was then incomplete. It was begun late in 1916, when, after the battle of the Somme, the German High Command had determined on the retreat which was carried out in February and March of the following year. It was dug by Russian prisoners, and the forced labour of French and Belgian peasants. The best engineering and tactical brains of the German Army went to its planning; and both officers and men believed it to be impregnable. The whole vast system was from four miles to seven miles deep, one interlocked and inter-communicating system of trenches, gun emplacements, machine-gun positions, fortified villages, and the rest, running from north-west to south-east across France, behind the German lines. In front of the British forces, writes an officer of the First Army, before the capture of the Drocourt-Quéant portion of the line, ran "line upon line, mile upon mile, of defences such as had never before been imagined; system after complicated system of trenches, protected with machine-gun positions, with trench mortars, manned by a highly-trained infantry, and by machine-gunners unsurpassed for skill and courage. The whole was supported by artillery of all calibres. The defences were the result of long-trained thought and of huge work. They had been there unbroken for years; and they had been constantly improved and further organised." And the great canals--the Canal du Nord and the Scheldt Canal, but especially the latter, were worked into the system with great skill, and strongly fortified. It is evident indeed that the mere existence of this fortified line gave a certain high confidence to the German Army, and that when it was captured, that confidence, already severely shaken, finally crumbled and broke. Indeed, by the time the British Armies had captured the covering portions of the line, and stood in front of the line itself, the _morale_ of the German Army as a whole was no longer equal to holding it. For our casualties in taking it, though severe, were far less than we had suffered in the battle of the Scarpe; and one detects in some of our reports, when the victory was won, a certain amazement that we had been let off--comparatively--so lightly. Nevertheless, if there had been any failure in attack, or preparation, or leadership, we should have paid dearly for it; and a rally on the Hindenburg line, had we allowed the enemy any chance of it, might have prolonged the war for months. But there was no failure, and there was no rally. Never had our tried Army leaders, General Horne, General Byng, and General Rawlinson carried out more brilliantly the general scheme of the two supreme Commanders; never was the Staff work better; never