Those who saw the position as a whole on this Friday, the 28th of August, wondered whether or not the French Commander-in-chief would order the continuation of the successful local attack at Guise, and so attempt to break the whole German line.  He did not give this order, and his reasons for retiring in the face of such an opportunity may be briefly stated thus:—­

1.  The French forces in line from Verdun to La Fere, and continued by the British contingent to the neighbourhood of Noyon, were still gravely inferior to the German forces opposed to them.  Even, therefore, if the French success at Guise had been pushed farther, and had actually broken the German line, either half of the French line upon either side of the forward angle would have been heavily outnumbered by the two limbs of the enemy opposed to each, and that enemy might perfectly well have defeated, though separated, each portion of the force opposed to it.

2.  To the west, at the position FF on Sketch 62, were acting large bodies of the enemy, which had swept, almost without meeting resistance, through Arras to Amiens.  Against that advance there was nothing but small garrisons of French Territorials, which were brushed aside without difficulty.

Now these bodies, though they were mainly of cavalry which were operating thus to the west, had already cut the main line of communications from Boulogne, upon which the British had hitherto depended, and were close enough to the Allied left flank to threaten it with envelopment, or, rather, to come up in aid of von Kluck at A, and make certain what he already could regard as probable—­his power to get round the British, and turn the whole left of the Allied line.

3.  More important even than these two first conclusive considerations was the fact that the French Commander-in-chief, had he proposed to follow up this success of his subordinate at Guise, would have had to change the whole of his general plan, and to waste, or at best to delay, the action of his chief factor in that plan.  This chief factor was the great manoeuvring mass behind the French line which had not yet come into play, and the advent of which, at a chosen moment, was the very soul of the French strategy.

It is so essential to the comprehension of the campaign to seize this last point that, at the risk of repetition, I will restate for the reader the main elements of that strategy.

[Illustration:  Sketch 63.]

I have called it in the earlier pages of this book “the open strategic square,” and I have shown how this theoretical arrangement was in practice complicated and modified so that it came to mean, under the existing circumstances of the campaign, the deliberate thrusting forth of the fraction called “the operative corner,” behind which larger masses, “the mass of manoeuvre,” were to come up in aid and assume the general counter-offensive when the operative corner should have drawn the enemy down to that position in which such a general counter-offensive would be most efficacious.