On the other hand, from the nature of the topography in this section of the Franco-Belgian border, the units of the French command had to fall back farther and more rapidly in proportion as they stretched eastward. The attack of the enemy in forces of rather more than two to one had come, as we have seen, not only from across the line of the Sambre, but, once Namur had fallen, from across the line of the Meuse at right angles to the line of the Sambre. Therefore the 5th and the 4th Armies, contained within the triangle bounded by the Sambre and Meuse, retiring from blows struck from the direction of the arrows 1-5 over all that hilly and wooded country known as the Thiérache, were, as to the extreme salient of them at A, compelled to a very rapid retirement indeed; and on this Sunday night the French line was deflected southward, not without heavy losses, until either on that night or on the Monday morning it joined up with the forces which stretched northward through and from Mézières. An attempt to counter-attack through the precipitous ravines and deep woods on to the valley of the Semois had failed, and the line as a whole ran, upon this night between the Sunday and the Monday, much as is indicated upon the accompanying sketch. [Illustration: Sketch 53.] From this it will be seen that the British contingent away upon the extreme left was in very grave peril, not only because the turning movement was wholly directed round their exposed flank, but also because, their retirement having come late, they stood too far forward in the general scheme at this moment, and therefore more exposed to the enemy's blow than the rest of the line. With this it must be remembered Tournai had already fallen. It was very imperfectly held by a French Territorial brigade, accompanied by one battery of English guns; and the entering German force, in a superiority of anything you like--two, three, or four to one--easily swept away the resistance proffered in this quarter. These German forces from Tournai had not yet, by the nightfall of Monday, come up eastward against the British, but they were on the way, and they might appear at any moment. The corps next to them, the 4th of von Kluck's five, was already operating upon that flank, and the next day, Wednesday, 26th of August, was to be the chief day of trial for this exposed British wing of the army. So far the operations of the British Army had not differed greatly from the expected or at least one of the expected developments of the campaign. The operative corner, if it should not have the luck, through losses or blunders on the part of the enemy, to take the counter-offensive after receiving the third shock, is intended to retire, and to draw upon itself a maximum of the enemy's efforts.