Nevertheless the clouds were beginning to lighten. The violence of the German attack was exhausting to the attackers; their communications now lay across the devastated area, and rain soon came to clog their movements. Their front of attack was, moreover, being steadily narrowed from fifty to twenty miles. The French had forced the Germans to leave the Oise after Noyon, and while their advance continued it did so with a lengthening flank no longer protected by the river. Unless Von Hutier to the south or Von Buelow to the north could break these containing and solidifying barriers, the front of the German attack would be reduced to a hopeless point before it got to Amiens. The attempt was naturally made against Arras by Von Buelow's comparatively unwearied army, and on the 28th he resumed his frustrated attack of the 23rd. This time the Germans had no fog to help them, and their troops assembling for the attack were decimated by our artillery. Nowhere did they succeed in piercing the battle zone, and a second attack in the afternoon fared no better. This was the decisive failure of the German offensive, and north of the Somme our front was now secure. South of it the Germans made some further progress on that day. The Rosières salient had to be abandoned to the Germans pushing south of it across the Somme, and a retreat made to the angle of the Luce and Avre rivers. Fayolle also was driven back to the Avre, but by counter-attacks north and south of Montdidier he prevented the enemy from debouching from that city.