I must here beg the reader's leave for a short digression in connection with those two phrases--"in favour of," and "vigour." History in general treats a retirement, particularly a rapid retirement accompanied by heavy losses, as a disaster; and the conception that such a movement may seem to the military historian a success, and that the energy of its conduct is just as important as the energy of an assault, is unfamiliar to most students of civilian record. But I am writing here, though an elementary, yet a military history; and to the military historian a retreat may be just as much a factor in victory as an advance; while the energy and tenacity required for its carriage are, if anything, more important than the corresponding qualities required for an advance. And in the case of this critical day and a half, the Wednesday, August 26th, and the Wednesday and Thursday night, August 26th-27th, the preservation of the British forces, and to some extent of all that lay east of them, was made possible by the very fact that the retirement was prosecuted with the utmost rapidity and without a halt. Had the retreat been interrupted in the hope of making a stand, or in the hope of repose, the whole army would have gone. Throughout the night, then, with heavy losses from stragglers, and in one case with the surrounding and annihilation by wounds and capture of nearly a whole battalion (the Gordons), the retreat of the 2nd Corps proceeded, and, in line with it, the retreat of the 1st Corps to the east. But this 1st Corps, though set an easier task than the 2nd (which, at the extreme of the line, was under the perpetual menace of development), did not retire without losses of a serious character. It was marching on Guise, just as the 2nd Corps to the west of it was marching across the watershed to St. Quentin. The Munster Fusiliers, who were on its extreme right, had halted for the night on that same evening of the 26th; for the 1st Corps, being less hard pressed, had more leisure for such repose. During the night a messenger was sent to this body with orders for the resumption of the march next morning. He was taken prisoner, and never reached his goal. The Munsters were attacked at dawn by the German pursuit in greatly superior numbers, surrounded and destroyed, as the Gordons of the 2nd Corps had been; the unwounded remnant was compelled to surrender. [Illustration: Sketch 58.] The whole of Thursday, the 27th, and Friday, the 28th of August, the British retreat continued, the 1st Corps following on at the valley of the Oise towards La Fère, while the 2nd Corps to the west passed St. Quentin, and made for Noyon, in the neighbourhood of the same river farther down; and on the night of that Friday the Expeditionary Force was at last in line, and in some kind of order, organized for the first breathing space possible after so terrible an ordeal. [Illustration: Sketch 59.]