Torrents of gas shells and high explosives were poured out upon our forward and battle lines, upon our Headquarters, upon our artillery positions, and upon all our lines of communication. The batteries of the 3rd and 5th Armies replied as best they could, but owing to the mist our artillery observers were helpless. It was impossible to see fifty yards ahead, and the German fire seemed to crash upon us out of some alien planet. By 8 or 9 o’clock the first parties of Germans had begun to advance, to cut our wire here and there along the front of attack, and to filter unobtrusively through our outpost line. We began to perceive that the enemy was behaving in a most unaccountable way. Even by 10 o’clock--as far as we could learn in the confusion--he seemed in some places to have made no attempt at an infantry attack at all. In others compact but apparently isolated little parties of Guards or Cockchafers, or men from some other picked regiment, had pushed right through our forward zone and were away beyond the places where the cross-fire from our machine-guns was to have checked them, before the men in the redoubts, half-blind amid the clouds of gas, had realised that any Germans had crossed No Man’s Land. Again and again the garrisons were overwhelmed from the rear before they could send back any warning to the men behind in the battle zone. When they did endeavour to signal, the S.O.S. would be blanketed in the mist. Only too often the first news of the attack to reach our batteries was the appearance of German infantry on their flank and rear. There would be nothing left but to mow down the enemy at point-blank range, till finally the gun crews were overwhelmed by the in-flooding tide. As at Ypres, we had begun amazedly to feel that we were up against a type of tactics against which we had never fought before. Our conjecture was perfectly right. It was a system of surprise, and of the theory of _Sturmtruppen_ carried to its extreme conclusion. Mr. Buchan has likened the new method to the advance of a hand whose finger-tips are shod with steel pushing its way into a soft substance. In practice the assault was conducted as follows: The infantry attack was preceded by a short but extremely intense bombardment in which a large proportion of gas was used. This was followed by the advance at irregular intervals of clusters of highly trained assault troops, carrying light trench mortars or machine-guns (each cluster really constituting a kind of human Tank. It was well, indeed, for us that they were no more than mere flesh and blood, and neither armoured nor engined.) These clusters, which were closely followed and supported by the field batteries, made gaps through which the line troops poured, guided by an elaborate system of flares and rockets. Each section of the defence might thus find itself caught between the “fingers”--outflanked and encircled.