Returning to the Third Corps, which we left in front of the Hindenburg system in the second week of September in the Epéhy district. The obstacle in front of the British was very formidable, for it consisted of their own old trench lines of March, with the Hindenburg system behind them. They had now reached the former British reserve line which had Ronssoy, Lempire, Epéhy, and Peizières as _points d'appui_. It was a front so strong that in March it is doubtful if the Germans could have carried it had the line not given way elsewhere. It was particularly necessary that the enemy should hold on to this stretch, because it covered the point where the great Canal du Nord ran under a tunnel for six miles between Bellicourt and Vandhuile--the only place where tanks could be used for an advance. The Germans had therefore massed strong forces here, including their famous Alpine Corps. The first task of the Third Corps was to get possession of the old British line in front of it, whence observation could be got of the Hindenburg position. This attack would form part of a general movement by the two southern Corps of the Third Army, the three Corps of the Fourth Army, and the northern portion of the First French Army. On that great day of battle, September 18, there was a universal advance along the line, which was carried out in the case of the Third Corps by the Seventy-fourth Division (Girdwood) on the right, the Eighteenth (Lee) right centre, the Twelfth (Higginson) left centre, and the Fifty-eighth Division left. Many of the characteristics of old trench warfare had come back into the battle, which was no longer open fighting, but is to be conceived as an attack upon innumerable scattered {67} trenches and posts very strongly held by the Germans, and their ultimate reduction by independent platoons and companies acting under their own regimental officers.