2.—Fortresses.
The assistance afforded by fortresses to the offensive does not extend beyond what is given by those close upon the frontiers, and is only feeble in influence; the assistance which the defensive can derive from this reaches further into the heart of the country, and therefore more of them can be brought into use, and their utility itself differs in the degree of its intensity. A fortress which is made the object of a regular siege, and holds out, is naturally of more considerable weight in the scales of war, than one which by the strength of its works merely forbids the idea of its capture, and therefore neither occupies nor consumes any of the enemy’s forces.