Some of the officers thought these things--I have read their letters-- but General von Kluck must have had only one dominating and absorbing thought, more important even than an Emperor's anger. "Gott im Himmel, shall I get this army back to a stronger line or shall I risk all on a fight in the open, against those French and British guns and almost equal odds?" The failure of the German centre was the gravest disaster, and threatened von Kluck with the menace of an enveloping movement by the Allied troops which might lead to his destruction, with the flower of the Imperial troops. Away back there on the Aisne were impregnable positions tempting to hard-pressed men. Leaving nothing to chance, the Germans had prepared them already in case of retreat, though it had not been dreamed of then as more than a fantastic possibility. The fortune of war itself as well as cautious judgment pointed back to the Aisne for safety. The allied armies were closing up, increasing in strength of men and guns as the hours passed. In a day or two it might be too late to reach the strongholds of the hills. 5 So the retreat of the German right wing which had cut like a knife through northern France until its edge was blunted by a wall of steel, began on September 5 and increased in momentum as the allied troops followed hard upon the enemy's heels. The great mass of the German left swung backwards in a steady and orderly way, not losing many men and not demoralized by this amazing turn in Fortune's wheel. "It is frightfully disappointing," wrote a German officer whose letter was found afterwards on his dead body. "We believed that we should enter Paris in triumph and to turn away from it is a bitter thing for the men. But I trust our chiefs and I know that it is only a strategical retirement. Paris will still be ours." Truly it was a strategical retirement and not a "rout," as it was called by the English Press Bureau. But all retirements are costly when the enemy follows close, and the rearguard of Von Kluck's army was in a terrible plight and suffered heavy losses. The French light artillery opened fire in a running pursuit, advancing their guns from position to position with very brief halts, during which the famous soixante-quinze flung out shells upon bodies of troops at close range--so that they fell like wheat cut to pieces in a hailstorm. The British gunners were pushing forward, less impetuously but with a steady persistence, to the west of the River Ourcq, and after all their hardships; losses, and fatigues, the men who had been tired of retreating were heartened now that their turn had come to give chase.