Quite irrespective of their influence as regards the means of subsistence of an army, country and ground bear another most intimate and never-failing relation to the business of war, which is their decisive influence on the battle, both upon what concerns its course, as well as upon the preparation for it, and the use to be made of it. We now proceed to consider country and ground in this phase, that is, in the full meaning of the French expression “Terrain.”
The way to make use of them is a subject which lies mostly within the province of tactics, but the effects resulting from them appear in strategy; a battle in the mountains is, in its consequences as well as in itself, quite a different thing from a battle on a level plain.
But until we have studied the distinction between offensive and defensive, and examined the nature of each separately and fully, we cannot enter upon the consideration of the principal features of the ground in their effects; we must therefore for the present confine ourselves to an investigation of its general properties. There are three properties through which the ground has an influence on action in war; that is, as presenting an obstacle to approach, as an obstacle to an extensive view, and as protection against the effect of fire-arms; all other effects may be traced back to these three.
Unquestionably this threefold influence of ground has a tendency to make warfare more diversified, more complicated, and more scientific, for they are plainly three more quantities which enter into military combinations.