Vienna is the heart of South Germany, and plainly Munich or Augsburg, in relation to France alone (Switzerland and Italy being therefore supposed neutral) would be more efficient as a principal fortress than Nuremburg or Wurzburg. But if, at the same time, we look at the roads leading from Italy into Germany by Switzerland and the Tyrol, this will become still more evident, because, in relation to these, Munich and Augsburg will always be places of importance, whereas Wurzburg and Nuremburg are much the same, in this respect, as if they did not exist.
We turn now to the second question Whether the fortresses should be placed on the frontier, or distributed over the country? In the first place, we must observe, that, as regards small states, this question is superfluous, for what are called strategic frontiers coincide, in their case, nearly with the whole country. The larger the state is supposed to be in the consideration of this question, the plainer appears the necessity for its being answered.
The most natural answer is, that fortresses belong to the frontiers, for they are to defend the state, and the state is defended as long as the frontiers are defended. This argument may be valid in the abstract, but the following considerations will show that it is subject to very many modifications.
Every defence which is calculated chiefly on foreign assistance lays great value on gaining time; it is not a vigorous counterstroke, but a slow proceeding, in which the chief gain consists more in delay than in any weakening of the enemy which is effected. But now it lies in the nature of the thing that, supposing all other circumstances alike, fortresses which are spread over the whole country, and include between them a very considerable area of territory, will take longer to capture than those squeezed together in a close line on the frontier. Further, in all cases in which the object is to overcome the enemy through the length of his communications, and the difficulty of his existence therefore in countries