We do not assert that Spain would be stronger without the Pyrenees than with them, but we say that a Spanish army, feeling itself strong enough to engage in a decisive battle, would do better by concentrating itself in a position behind the Ebro, than by fractioning itself amongst the fifteen passes of the Pyrenees. But the influence of the Pyrenees on war is very far from being set aside on that account. We say the same respecting an Italian army. If it divided itself in the High Alps it would be vanquished by each resolute commander it encountered, without even the alternative of victory or defeat; whilst in the plains of Turin it would have the same chance as every other army. But still no one can on that account suppose that it is desirable for an aggressor to have to march over masses of mountains such as the Alps, and to leave them behind. Besides, a determination to accept a great battle in the plains, by no means excludes a preliminary defence of the mountains by subordinate forces, an arrangement very advisable in respect to such masses as the Alps and Pyrenees. Lastly, it is far from our intention to argue that the conquest of a mountainous country is easier than that of a level(*) one, unless a single victory sufficed to prostrate the enemy completely. After this victory ensues a state of defence for the conqueror, during which the mountainous ground must be as disadvantageous to the assailant as it was to the defensive, and even more so. If the war continues, if foreign assistance arrives, if the people take up arms, this reaction will gain strength from a mountainous country.
It is here as in dioptrics, the image represented becomes more luminous when moved in a certain direction, not, however, as far as one pleases, but only until the focus is reached, beyond that the effect is reversed.
If the defensive is weaker in the mountains, that would seem to be a reason for the assailant to prefer a line of operations in the mountains. But this will seldom occur, because the difficulties of supporting an army, and those arising from the roads, the uncertainty as to whether the enemy will accept battle in the mountains, and even whether he will take