We have said in the preceding chapter that a position so strong through nature, assisted by art, that it is unassailable, does not come under the meaning of an advantageous field of battle, but belongs to a peculiar class of things. We shall in this chapter take a review of what constitutes the nature of this peculiarity, and on account of the analogy between such positions and fortresses, call them strong positions.
Merely by entrenchments alone they can hardly be formed, except as entrenched camps resting on fortresses; but still less are they to be found ready formed entirely by natural obstacles. Art usually lends a hand to assist nature, and therefore they are frequently designated as entrenched camps or positions. At the same time, that term may really be applied to any position strengthened more or less by field works, which need have nothing in common with the nature of the position we are now considering.
The object of a strong position is to make the force there stationed in point of fact unattackable, and by that means, either really to cover a certain space directly, or only the troops which occupy that space in order then, through them, in another way to effect the covering of the country indirectly. The first was the signification of the lines of former times, for instance, those on the French frontier; the latter, is that of entrenched camps laid out near fortresses, and showing a front in every direction.
If, for instance, the front of a position is so strong by works and hindrances to approach that an attack is impossible, then the enemy is