ARTICLE VI. Of the Coup D'Oeil
The coup d'oeil may be reduced, properly speaking, to two points; the first of which is the having abilities to judge how many troops a certain extent of country can contain. This talent can only be acquired by practice, for after having laid out several camps, the eye will gain so exact an idea of space, that you will seldom make any material mistake in your calculations.
The other, and by far the most material point, is to be most material point, is to be able to distinguish at first sight all the advantages of which any given space of ground is capable. This art is to be acquired and even brought to perfection, though a man be not absolutely born with a military genius.
Fortification, as it possesses rules that are applicable to all situations of an army, is undoubtedly the basis and foundation of this coup d'oeil. Every defile, marsh, hollow way, and even the smallest eminence, will be converted by a skilful general, to some advantage.
Two hundred different positions may sometimes be taken up in the space of two square leagues, of which an intelligent general knows how to select that which is the most advantageous. In the first place, he will ascend even the smallest eminences to discover and reconnoitre the ground; and assisted by the same rules of fortification, he will be enabled to find out the weak part of the enemy's order of battle. If time permit, the general would do well to pace over the ground, when he has determined on his general position.
Many other advantages may also be derived from the same rules of fortification, such as, the manner of occupying heights, and how to choose them, that they may not be commanded by others; in what manner the wings are to be supported, that the flanks may be well covered; how to take up positions that may be defended, and avoid those which a man of reputation cannot, without great risk, maintain. These rules will also enable him to discover where the enemy is weakest, either by having taken an unfavorable position, distributed his force without judgment, or from the slender means of defence which he derives from his situation. I am led by these reflections to explain in what manner troops ought to be distributed so as to make the most of their ground.