If the possession of ground was the object of the combat, then the decision generally lies in its loss.

Still not always, only if this ground is of peculiar strength, ground which is easy to pass over, however important it may be in other respects, can be re-taken without much danger.
3.

But in all other cases, when these two circumstances have not already decided the combat, therefore, particularly in case the destruction of the enemy's force is the principal object, the decision is reached at that moment when the conqueror ceases to feel himself in a state of disintegration, that is, of unserviceableness to a certain extent, when therefore, there is no further advantage in using the successive efforts spoken of in the twelfth chapter of the third book.

On this ground we have given the strategic unity of the battle its place here.
A battle, therefore, in which the assailant has not lost his condition of order and perfect efficiency at all, or, at least, only in a small part of his force, whilst the opposing forces are, more or less, disorganised throughout, is also not to be retrieved; and just as little if the enemy has recovered his efficiency.
The smaller, therefore, that part of a force is which has really been engaged, the greater that portion which as reserve has contributed to the result only by its presence.

So much the less will any new force of the enemy wrest again the victory from our hands, and that Commander who carries out to the furthest with his Army the principle of conducting the combat with the greatest economy of forces, and making the most of the moral effect of strong reserves, goes the surest way to victory.
We must allow that the French, in modern times, especially when led by Buonaparte, have shown a thorough mastery in this.
Further, the moment when the crisis-stage of the combat ceases with the conqueror, and his original state of order is restored, takes place sooner the smaller the unit he controls.