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.

To concentrate the great mass of manoeuvre was a business of some
days, and having ordered its concentration in one district, it would
be impossible to change the plan at a moment's notice. The district
into which a great part of this mass of manoeuvre had been
concentrated--or, rather, was in course of concentration at this
moment, the 28th August--was the district behind and in the
neighbourhood of Paris. It lay far from the scene of operation at
Guise. It was intended to come into play only when the general retreat
should have reached a line stretching from Verdun to the neighbourhood
of Paris itself. To have pursued the success at Guise, therefore,
would have been to waste all this great concentration of the mass of
manoeuvre which lay some days behind the existing line, and in
particular to waste the large body which was being gathered behind and
in the neighbourhood of Paris.

With these three main considerations in mind, and in particular the
third, wh