The Battle of the Marne by G.H. Perris — Read

The unescapable dilemma of the Joffrean strategy had developed into a second and peremptory phase. In deciding to withdraw from the Brie plateau and the Marne, rather than risk his rear and communications for the chance of a victory on the Seine, Kluck, or his superiors, had, doubtless, chosen the lesser evil. The marching wing of the invasion was crippled before the offensive of the Allies had begun; but Gallieni's precipitancy had brought a premature arrest upon the 6th Army. Beside this double check, we have now to witness a race between two offensive movements -- Bülow and Hausen pouring south with the impetuosity of desperation, while, along their right, the British Force and the French 5th Army struck north between the two western masses of the enemy with the fresh energy of an immense hope. Which will sooner effect a rupture?

Logically, there should be no doubt of the answer. Kluck was mainly occupied with Maunoury; Bülow, with Foch. Between them, there was no new army to engage the eight corps of Sir John French and Franchet d'Espérey. The cavalry and artillery force of Marwitz and Richthofen, strong as it was, could do no more than postpone the inevitable -- always provided that Maunoury and Foch could hold out. Every day, the pull of Kluck to the north-west and of Bülow to the south-east must become more embarrassing. French writers have applied an expressive phrase to the influence of this pull -- "effet de ventouse," effect of suction -- though hardly appreciating its double direction. The maintenance of a continuous battle-line is axiomatic in modern military science. It follows from the size of the masses in action, the difficulty, even with steam and petrol transport, of moving them rapidly, and their dependence upon long lines of supply.