The end of September and the beginning of October found both the Germans and the Allied Armies extending their flanks westward. As growing familiarity with the trench system of warfare began to make it clear to both sides that no further progress was possible by means of direct pressure, the German and Allied leaders began to scent a more favourable outlet for their energies on the western flank of operations, where--and where only--a roadway still lay open. The gradual shifting of German troops westward, or, to be more accurate, north-westward, could have no meaning but that of an attempt to force their way into France along the flat plains of Western Flanders; and no sooner was such an intention made plain than a corresponding movement was made by the Allies in an endeavour to forestall the enemy and envelop his flank before he could extend it. It was clear that the German move postulated the speedy capture of Antwerp, as the fall of that fortress was a necessary preliminary to any extended movement along the Belgian seaboard. A considerable British force was in process of being sent to Antwerp, and in addition to this force, the 7th Division and 3rd Cavalry Division were landed at Zeebrugge on October 7th, with a view to co-operating either with the Antwerp troops or with the main Allied Army as circumstances dictated. A consideration of these several important factors in the situation suggested to the C. in C. the desirability of entrusting the western extension movement, in the first instance, to the British Army at the moment occupying the Aisne trenches. Not only would such an exchange of positions greatly increase the facilities for bringing up supplies and for communications generally with England, but, in the event of the co-operation of the 7th and 3rd Cavalry Divisions, it would have the advantage of putting that detached body of troops in touch with the left of the main British Army and so of consolidating the command. General Joffre at first demurred, on account of the obvious objections attending the transfer from one set of troops to another of trenches situated so very close to those of the enemy as were ours on the Aisne, such transfer only being possible at night and under the strictest precautions. The C. in C, however, was insistent, and in the end the French General was persuaded that the advantages of the plan outweighed the drawbacks. There can be no question now but that the judgment of the C. in C. was fully endorsed by the event.