Divisions have been cut off and made prisoners through the disruption of the plan of the battle;—­if the line of retreat begins to be endangered:  the Commander may tell very well in which direction he is going with his battle.  The longer this direction continues, the more decided it becomes, so much the more difficult will be the turning, so much the nearer the moment when he must give up the battle.  We shall now make some observations on this moment.

We have already said more than once that the final decision is ruled mostly by the relative number of the fresh reserves remaining at the last; that Commander who sees his adversary is decidedly superior to him in this respect makes up his mind to retreat.  It is the characteristic of modern battles that all mischances and losses which take place in the course of the same can be retrieved by fresh forces, because the arrangement of the modern order of battle, and the way in which troops are brought into action, allow of their use almost generally, and in each position.  So long, therefore, as that Commander against whom the issue seems to declare itself still retains a superiority in reserve force, he will not give up the day.  But from the moment that his reserves begin to become weaker than his enemy’s, the decision may be regarded as settled, and what he now does depends partly on special circumstances, partly on the degree of courage and perseverance which he personally possesses, and which may degenerate into foolish obstinacy.  How a Commander can attain to the power of estimating correctly the still remaining reserves on both sides is an affair of skilful practical genius, which does not in any way belong to this place; we keep ourselves to the result as it forms itself in his mind.  But this conclusion is still not the moment of decision properly, for a motive which only arises gradually does not answer to that, but is only a general motive towards resolution, and the resolution itself requires still some special immediate causes.  Of these there are two chief ones which constantly recur, that is, the danger of retreat, and the arrival of night.

If the retreat with every new step which the battle takes in its course becomes constantly in greater danger, and if the reserves are so much diminished that they are no longer adequate to get breathing room, then there is nothing left but to submit to fate, and by a well-conducted retreat to save what, by a longer delay ending in flight and disaster, would be lost.

But night as a rule puts an end to all battles, because a night combat holds out no hope of advantage except under particular circumstances; and as night is better suited for a retreat than the day, so, therefore, the Commander who must look at the retreat as a thing inevitable, or as most probable, will prefer to make use of the night for his purpose.

That there are, besides the above two usual and chief causes, yet many others also, which are less or more individual and not to be overlooked, is a matter of course; for the more a battle tends towards a complete upset of equilibrium the more sensible is the influence of each partial result in hastening the turn.  Thus the loss of a battery, a successful charge of a couple of regiments of cavalry, may call into life the resolution to retreat already ripening.