By directing a force against the enemy’s flank and rear its efficacy may be much intensified; but this is so far from being a necessary result always that the efficacy may, on the other hand, be just as much weakened.  The circumstances under which the combat has taken place decide upon this part of the plan as well as upon every other, without our being able to enter thereupon here.  But, at the same time, there are in it two things of importance for our subject:  first, flank and rear attacks have, as A rule, A more favourable effect on the consequences of the decision than upon the decision itself.  Now as concerns the retrieving a battle, the first thing to be arrived at above all is a favourable decision and not magnitude of success.  In this view one would therefore think that a force which comes to re-establish our combat is of less assistance if it falls upon the enemy in flank and rear, therefore separated from us, than if it joins itself to us directly; certainly, cases are not wanting where it is so, but we must say that the majority are on the other side, and they are so on account of the second point which is here important to us.

This second point is the moral effect of the surprise, which, as A rule, A reinforcement coming up to re-establish A combat has generally in its favour.  Now the effect of a surprise is always heightened if it takes place in the flank or rear, and an enemy completely engaged in the crisis of victory in his extended and scattered order, is less in a state to counteract it.  Who does not feel that an attack in flank or rear, which at the commencement of the battle, when the forces are concentrated and prepared for such an event would be of little importance, gains quite another weight in the last moment of the combat.

We must, therefore, at once admit that in most cases a reinforcement coming up on the flank or rear of the enemy will be more efficacious, will be like the same weight at the end of a longer lever, and therefore that under these circumstances, we may undertake to restore the battle with the same force which employed in a direct attack would be quite insufficient.  Here results almost defy calculation, because the moral forces gain completely the ascendency.  This is therefore the right field for boldness and daring.

The eye must, therefore, be directed on all these objects, all these moments of co-operating forces must be taken into consideration, when we have to decide in doubtful cases whether or not it is still possible to restore a combat which has taken an unfavourable turn.