In the dim light of the very early morning of May 16, after a heavy shell-fall, a new division of the enemy was thrust forward just north of the Scarpe. In a long day's fighting it was practically destroyed, for though in its first ardent advance it flowed over the shot-shattered advance posts, it was finally held, and then after a long tussle was shot out of its new positions by the rifles and Lewis guns, until before evening it was back whence it started. In this brisk action thousands of the assailants were killed or wounded with nothing to show for it save the substantial losses which they inflicted. This very severe attack fell mainly upon the Fifty-first Division, who showed once more that British formations, even if penetrated, are very far from being defeated. On May 18 there was a spirited local operation by the 8th Middlesex of the 167th Brigade, in which they made a very gallant bombing attack upon that portion of Tool Trench which was not yet in British hands. The opposition, however, was so strong that no permanent good could be effected. On the next day there was a further attempt to get forward, both by the 167th and by its neighbour, the 87th Brigade. The fire was too deadly, however, and the advance {87} was not successful. This failure seems to have been due to a knowledge on the part of the enemy as to the coming assault, for the machine-gun fire and the barrage opened in full force at the very moment when the leading line of infantry sprang over the lips of their assembly trenches. [Sidenote: May 20] May 20 marked a successful advance of the Thirty-third Division on the right of the Seventh Corps, against the Hindenburg Line in the Sensée Valley and southwards towards Bullecourt. On this occasion there was no preliminary bombardment and no creeping barrage. A mist helped the 98th Brigade to deploy unobserved under the bulge of the chalk hills that rise to the south of the Sensée Valley. When this mist rose the Germans had a fine, though transitory, view of British tactics, for the battalions were advancing as upon an Aldershot field day. The 100th Brigade worked down the Hindenburg Line north of the river, crossed it, and joined hands with their comrades on the south. It was a complete surprise, and counter-attack was checked by the volume of the British gun-fire which tore up the whole rear of the German defences. The result was the capture of more than a mile of the front line on either side of the Sensée River, with half a mile of the support line, and 170 prisoners, with many machine-guns. The losses in this well-managed affair were well under a thousand. [Sidenote: May 30]