circumvallation only in reality covers that portion of the theatre of war which it actually encloses; all the rest is more or less given up to the enemy if special detachments are not made use of to cover it, in which way the very partition of force which it was intended to obviate takes place. Thus the besieging army will be always in anxiety and embarrassment on account of the convoys which it requires, and the covering the same by lines of circumvallation, is not to be thought of if the army and the siege supplies required are considerable, and the enemy is in the field in strong force, unless under such conditions as are found in the Netherlands, where there is a whole system of fortresses lying close to each other, and intermediate lines connecting them, which cover the rest of the theatre of war, and considerably shorten the lines by which transport can be affected. In the time of Louis the Fourteenth the conception of a theatre of war had not yet bound itself up with the position of an army. In the Thirty Years’ War particularly, the armies moved here and there sporadically before this or that fortress, in the neighbourhood of which there was no enemy’s corps at all, and besieged it as long as the siege equipment they had brought with them lasted, and until an enemy’s army approached to relieve the place. Then lines of circumvallation had their foundation in the nature of circumstances.
In future it is not likely they will be often used again, unless where the enemy in the field is very weak, or the conception of the theatre of war vanishes before that of the siege. Then it will be natural to keep all the forces united in the siege, as a siege by that means unquestionably gains in energy in a high degree.
The lines of circumvallation in the reign of Louis XIV., at Cambray and Valenciennes, were of little use, as the former were stormed by Turenne, opposed to Condé, the latter by Condé opposed to Turenne; but we