On the southern end of the Picardy battle line General Humbert's army continued to press the advance toward Noyon. The desperate defense maintained by the Germans on the Chaulnes-Roye road for a time delayed French storming operations which were impending. General Rawlinson's army, which held the line to the north of the French positions, was subjected to fierce German attacks on the whole front. The enemy seemed determined to maintain his hold on the Chaulnes heights regardless of the cost. The French advance was made against a line that was thinly held, but which bristled with machine guns so numerous that there was one to every two men, it was reported. Moreover, the battle area traversed by the French troops was deluged with mustard gas, so that there were days in which they were forced to wear their masks even when snatching a few hours of repose. Yet the French continued to win dominating positions and forced the Germans back in spite of all attempts to hinder their progress. On August 15, 1918, Australian troops under Marshal Haig made a drive against the German defenses on the center of the Somme battle front between Chaulnes and Roye and captured the villages of Parvillers and Demery. Progress was also made south of the Somme, southeast of Proyart, and to the northwest of Chaulnes. North of Albert, in the sector where the Germans were forced to evacuate their positions which projected into the British line between Beaumont-Hamel and Bucquoy, Haig's troops continued to push forward. On General Humbert's front east of Montdidier his tireless fighters conquered two strongly fortified farms to the northwest of Ribécourt. Albert was still strongly held by the Germans, and British patrols entering the town were fired upon from the cathedral. The steady advance of the Allies, however, so seriously menaced the German positions in and around the town that it was only a question of time when they would be forced to retire from every point of defense. On August 16, 1918, British and French troops, operating together, made a drive against the strongly held German positions between Chaulnes and Roye. Advancing on an eight-mile front from a point west of Fransart to the neighborhood of Laucourt, they made substantial progress and reduced a number of important German strongholds. Forward movements were also made by the British in the Ancre sector in which the Germans were forced to withdraw their first-line positions, and Haig's men pushed ahead on the three-mile front between Beaucourt on the Ancre and Puisieux-au-Mont.