PHASES OF THE BATTLE.--There are three principal phases of every battle. Information must be obtained by observation and by fighting; advantage must be taken of information so obtained to strike where the blow or blows will be most effective; success obtained by fighting must be developed until the enemy is annihilated.
_Information and the Initiative_.--Much work requires to be done in the air and on the land before the rival armies come face to face. Aircraft and the independent cavalry (advanced mounted troops and fast tanks detached from divisions for the purpose), endeavour to ascertain whether, and if so in what locality and in what strength, troops are being concentrated by the enemy. From information so obtained the Headquarters Staff are able to conjecture the intentions and aims of the enemy, and the extent to which their own intentions and aims have been perceived by the enemy. After the enemy is encountered this information is at the service of the Commander of the troops, but it will generally require to be supplemented by fighting. On each side the commander will be striving to obtain the _initiative_, to impose his will upon his opponent, for the commander who loses the initiative is compelled to conform to the plans and movements of his adversary, instead of bringing into operation plans and movements better suited to his own purposes. Each is scheming to obtain or retain the liberty of manoeuvre, in the same way as, in the days of sailing ships, a naval commander strove to get the "weather gauge" in every encounter.
The initiative won by the Strategy of one commander { 27} is sometimes wrested from him by the Tactics of his adversary. This was exemplified at the _Battle of Salamanca_ (July 22, 1812). Wellington, the generalissimo of the Anglo-Portuguese forces, had decided to withdraw behind the River Tormes to the stronghold Ciudad Rodrigo, and had dispatched his train to that centre. The French Commander (Marmont), in his eagerness to intercept Wellington's line of retreat, moved part of his force to the Heights of Miranda, thus threatening Wellington's right and rear, but leaving a gap of two miles between the detached force and his main army. Wellington noted the fresh disposition of Marmont's army through his telescope, and exclaiming, "That will do!" he abandoned all idea of the withdrawal which had been forced upon him by Marmont's previous manoeuvres, and hurled part of his force against the detached body (which was defeated before Marmont could send assistance) and at the same time barred the progress of the main army, which was forced to leave the field. Wellington afterwards declared, "I never saw an army receive such a beating." If the Spanish General in alliance with Wellington had not, contrary to the most explicit instructions, evacuated the Castle of Alba de Tormes (which commanded the fords over which the French retreated), "not one-third of Marmont's army would have escaped" (Napier).