Meanwhile heavy forces of the Allies had been massed against the German right flank. The next effort of the Germans consequently was to push back those forces. They met the outflanking movement in the way such movements can best be met—by trying to outflank the outflankers.
At this time the Allied forces on the flank extended from near Noyon on the Oise northward to the Somme. The Germans promptly pushed westward in force north of the Somme and across the outside edge of the Allied line to the town of Albert and the heights commanding it.
With notable promptitude, however, the Allied line was extended across the Somme to the north, and by the west of Arras, and the German movement was held. Gradually, after days of obstinate fighting, the enemy were battled out of Albert and then out of Arras; and the Allied outflanking line was stretched up to Bethune and La Bassée.
Night and day, day and night, by railway, by motor-omnibus, on motor-cars,[33] French troops during three whole weeks were rushed up from the south and west of France. This movement towards the fighting line had begun with the pursuit after the Battle of the Marne. It never ceased. First the army of General de Castlenau appeared on the front. Next came the army of General de Maudhuy. Territorials and marines from the fleet were hurried into the service; divisions of cavalry spaced out the line, and defended communications. In Germany as in France no effort was spared. The issue was momentous. During these first weeks of October the German Government put forth its supreme effort to stem and to turn the adverse tide of war. Hitherto they had found their measures baffled. Two new and powerful French armies had fastened on to the flank of their position. Their own forces had come up just too late. The peril was menacing and it was growing. They redoubled their energies.
Their decision was another supreme effort to outflank the outflankers. With fresh masses of Reservists, sent westward at all possible speed, they pushed behind a heavy screen of cavalry across the Aa and across the Lys at Estaires and threatened the rear of the French troops holding Bethune.
It is probably not realised that this was strategically the most important offensive movement the Germans had made in the western theatre of war since their advance upon Paris.
Yet that undoubtedly was the fact. Had the movement succeeded it must not only have given them control of the north-east coast of France as far probably as Havre, but it must have rolled up the Allied line as far as Noyon. The whole original scheme of turning the Allies' left flank would have been within realisation.
The movement did not succeed. It was met by a counter-move probably as unexpected by the Germans as it was bold. The counter-move was the transfer of the British army from the Aisne.
Recognising the decisive character of these operations, General Joffre had entrusted the control of affairs on this part of the front to General Foch, not only one of the ablest among the able soldiers whom this war has shown the French Army to possess, but one of the most brilliant authorities on the science of modern military tactics. As he had met the situation magnificently at Sezanne, so now he met it with equal resource under circumstances hardly less critical.
There were now three French armies on the German flank, and they fought as they were led with a skill equal to their valour. Yet the necessity remained for a great counter-stroke. In view of that necessity the idea occurred to Sir John French to transfer the British army, a proposal to which General Joffre at once agreed.