Feuquière says that “we should never wait for the enemy in the lines of circumvallation, but we should go out and attack him.” He is in error. There is no authority in war without exception; and it would be dangerous to proscribe the principle of awaiting the enemy within the lines of circumvallation.
NOTE.
During the siege of Mons, in 1691, the Prince of Orange assembled his army, and advanced as far as Notre Dame de Halle, making a demonstration to succor the place. Louis XIV, who commanded the siege in person, called a council of war to deliberate on what was to be done in case the Prince of Orange approached. The opinion of Marshal Luxembourg was to remain within the lines of circumvallation, and that opinion prevailed.
The marshal laid it down as a principle that, when the besieging army is not strong enough to defend the whole extent of circumvallation, it should quit the lines and advance to meet the enemy; but when it is strong enough to encamp in two lines around a place, that it is better to profit by a good entrenchment—more especially as by this means the siege is not interrupted.
In 1658, Marshal Turenne was besieging Dunkirk. He had already opened the trenches, when the Spanish army, under the orders of the Prince Don Juan, Condé, and D’Hocquincourt, appeared in sight, and took post upon the Downs, at a distance of a league from his lines. Turenne had the superiority in numbers, and he determined to quit his entrenchments. He had other advantages also. The enemy was without