successfully held the enemy at bay from early morning until 6 p.m., when the eleven survivors withdrew under orders, having accomplished their task. There are many instances of the occupation of an area for an actual or potential tactical purpose. Before the _Battle of Salamanca_ (July 22, 1812) a Spanish force had been detached by Wellington to cover a ford of the River Tormes by occupying the castle of Alba de Tormes, but the force was withdrawn without Wellington's knowledge, and Marmont's defeated army retired unmolested over the ford to the fortress of Valladolid. In the campaign of 1814, Napoleon placed a garrison of 1,200 in the _Fortress of Soissons_, but on March 3,1814, the garrison capitulated without exhausting all the means of defence as the regulations of War ordain, and the bridge at Soissons enabled Bluecher and Buelow to unite their forces across the River Aisne. In the Waterloo campaign, Wellington stationed 17,000 men at _Hal_ and _Tubize_, 8 miles from his right on the field of battle at Waterloo, to repel a possible turning movement and to form a rallying point if his centre was broken, and with 67,000 men took up a position astride the Nivelle-Brussels and Charleroi-Brussels roads which met at Mont St. Jean. He was deprived of the services of this detachment and modern criticism has been directed against this disposition of his forces. It is, however, permissible to suggest that the security of his right flank, and the possession of a rallying point, inspired him with the confidence which enabled him to {79} withstand the sustained attacks of Napoleon until the arrival of Bluecher's corps permitted him to overwhelm his adversary. A further form of defensive action is the occupation of a series of extemporised positions and the orderly withdrawal to a further series before the actual assault of the enemy, resistance being combined with manoeuvre for the purpose of delaying the enemy's advance or of holding up his pursuit. Delaying action of this kind is commonly employed in rearguard fighting, when the object to be gained is time rather than position, and the offensive action of the defender is limited to local counter-attacks at favourable or desperate moments. But the guiding principle in all defensive operations, including delaying action, must be that "when an enemy has liberty of manoeuvre, the passive occupation of a position, however strong, can rarely be justified, and always involves the risk of crushing defeat" ("Field Service Regulations," vol. ii. (1920)).