A two-mile trench system, believed to be impregnable, was stormed by the Allied forces near Thiepval September 17, while south of the Somme the French took the German trenches along a front of three miles.  Next day more ground was taken in the advance toward Bapaume and German prisoners continued to fall into the Allies’ hands.  The number of Teuton captives taken during the Somme fighting from July 1 to September 22 was placed at 55,800 men and officers.

The month of September was remarkable for the great number of aerial combats on the western front and the efficiency developed in this mode of fighting.  Many airplanes were shot down on both sides, but the Allies seemed to be gaining the mastery of the air.  On a single day, September 24, over a hundred air combats were reported, during which fifty-seven airplanes were destroyed.  On the same day two French airmen, in flights of 500 miles, dropped bombs on the Krupp works at Essen in Germany.

In a forward sweep near the end of the month the British took a number of German positions northeast of Combles, while the French advanced south of that point, so that the two armies almost surrounding it were scarcely a mile apart.  A day later British and French troops entered Comibles from opposite sides and drove the Germans out.  Continuing the drive from Thiepval, which had also been occupied, the British consolidated their positions and straightened their line a short distance from Bapaume, their objective point at this time.  More than 5,000 German prisoners were taken September 26 and 27.

More Allied gains in the Somme sector were reported in the first week of October.  German counter-attacks were frequent, but lacked the vigor and success of former efforts on this front.  In a joint attack on October the village of Le Sars was taken and the Allies found themselves within two miles of Bapaume.  General Foch with his French infantry took a number of German positions near Ablaincourt, south of the Somme, October 14, and held his gains against repeated German attacks.  The fighting was extremely desperate and of a hand-to-hand character.  Gas and liquid fire were used by the Germans, but the new Allied lines were firmly held.  Liquid fire was also used against the British at Thiepval, but without success.

The Allied attacks on the Somme from October 9 to October 13 were reckoned in Berlin dispatches as amongst the greatest actions of the entire Somme battle, the enemy believing that the Allies themselves then attempted to reach a decision by breaking through the German lines on the largest possible scale.  The losses on both sides during this period were admittedly very heavy.

On October 18 the town of Sailly-Saillisel fell to the French after hard fighting and commanding ridges on either side of it were also captured.  Fresh progress brought the French troops to the outskirts of Peronne next day, and on the 21st the British advanced their lines along a front of three miles, capturing the Stuff and Regina redoubts and trenches and taking more than 1,000 prisoners, besides bringing down seventeen enemy airplanes.