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, which was far the most important, General Joffre determined to give up the advantage obtained at Guise, to order the two successful army corps under Maunoury, who had knocked the Prussian Guard at that point, to retire, and to continue the general retreat until the Allied line should be evenly stretched from Paris to Verdun.  The whole situation may be put in a diagram as follows:  You have the Allied line in an angle, ABC.  You have opposed to it the much larger German forces in a corresponding angle, DEF.  Farther east you have a continuation of the French line, more or less immovable, on the fortified frontier of Alsace-Lorraine at M, opposed by a greater immovable German force at N. At P you have coming up as far as Amiens large German bodies operating in the west, and at Q a small newly-formed French body, the 6th French Army, supporting the exposed flank of the British contingent at A, near Noyon.  Meanwhile you have directed towards S, behind Paris, and coming up at sundry other points, a concentration of the mass of manoeuvre.

[Illustration:  Sketch 64.]

It is evident that if the French offensive at B which has successfully pushed in the German elbow at E round Guise is still sent forward, and even succeeds in breaking the German line at E, “the elbow,” the two limbs into which the Germans will be divided, DE and EF, are each superior in number to the forces opposed to them, and that DE in particular, with the help of P, may very probably turn AB and its new small supporter at Q, roll it up, and begin a decisive victory, while the other large German force, EF, may press back or pierce the smaller opposed French force, BC.

Meanwhile you would not only be risking this peril, but you would also be wasting your great mass of manoeuvre, SS, which is still in process of concentration, most of it behind Paris, and which could not possibly come into play in useful time at E.

It is far better to pursue the original plan to continue the retreat as far as the dotted line from Paris to Verdun, where you will have the whole German force at its farthest limit of effort and corresponding exhaustion, and where you will have, after the salutary delay of the few intervening days, your large mass of manoeuvre, SS, close by to Paris and ready to strike.