4. Mountains in their relation to the provisioning of an army.
This is a very simple subject, easy to understand. The opportunity to make the best use of them in this respect is when the assailant is either obliged to remain in the mountains, or at least to leave them close in his rear.
These considerations on the defence of mountains, which, in the main, embrace all mountain warfare, and, by their reflection, throw also the necessary light on offensive war, must not be deemed incorrect or impracticable because we can neither make plains out of mountains, nor hills out of plains, and the choice of a theatre of war is determined by so many other things that it appears as if there was little margin left for considerations of this kind. In affairs of magnitude it will be found that this margin is not so small. If it is a question of the disposition and effective employment of the principal force, and that, even in the moment of a decisive battle, by a few marches more to the front or rear an army can be brought out of mountain ground into the level country, then a resolute concentration of the chief masses in the plain will neutralise the adjoining mountains.
We shall now once more collect the light which has been thrown on the subject, and bring it to a focus in one distinct picture.
We maintain and believe we have shown, that mountains, both tactically and strategically, are in general unfavourable to the defensive, meaning thereby, that kind of defensive which is decisive, on the result of which the question of the possession or loss of the country depends. They limit the view and prevent movements in every direction; they force a state of passivity, and make it necessary to stop every avenue or passage, which always leads more or less to a war of cordons. We should therefore, if possible, avoid mountains with the principal mass of our force, and leave them on one side, or keep them before or behind us.