Uncanny work it was awaiting, in the silence of quietest of quiet lines, a mighty attack of which for very long there was scarce an indication. In the earlier days, save for reports from higher formations of aerodromes, hospitals, and railways far behind the German lines, the sole warning sign was in the large numbers of officers, maps in hand, observing day by day the British trenches and the country behind them. There was no great increase of movement on forward roads till about the 12th of March. Aeroplane photographs taken about this date showed that a large number of shell-holes a few hundred yards from the outpost line had been worked upon. It was surmised that these were being prepared for trench mortars, for the destruction of the British front-line system, as that of the Russians had been destroyed before the last great German advance at Riga. Significant also, in this connection, was the fact that Oskar von Hutier, who had carried out that attack, was now in line opposite, in command of Eighteenth Army. His known character and antecedents were food for reflection. New military roads were also discovered behind Itancourt. But it was a few clear mornings and evenings, from the 15th of March onwards, that brought most conclusive evidence of what was impending. From the dovecote in Essigny, the best observation post on the XVIII. Corps front, which was manned by the 36th Division's excellent observers, an enormous amount of traffic could now be observed. Along the main road from Guise-Mont d'Origny to St. Quentin, in particular, huge convoys of lorries and horse transport were seen, as dusk drew in, moving towards the last-named city. Small place for doubt now remained. On March the 4th occurred a curious incident. The Germans had apparently come to the conclusion that the British front line had been abandoned; and, indeed, it was held lightly enough by isolated sections. Strong patrols, amounting in general to a platoon, suddenly issued from the German trenches all along the 36th Division's front, in broad daylight. The outposts might be weak, but they could resist an attempt of this sort. Under the fire of Lewis guns all the patrols were stopped and dispersed with heavy loss. Patrols sent out in turn from the outpost companies captured in all one officer and ten other ranks. It was a sharp lesson, and thereafter, till the opening of the attack, was no move by the German infantry.