2. When cavalry is posted on the flanks, it should _not usually be on the first line of infantry_. If it is to be used for attack, it is better to keep it retired from view till the last moment, in order to strengthen its attack by the powerful moral effect of a surprise. And, used defensively, it will be best posted on the flanks of the second line; since, in advancing to charge, it must have a clear space in its front of at least two hundred or three hundred yards, to enable it to act with freedom and vigor. 3. But if a position can be found for cavalry in front, where it would not be too much exposed, this may sometimes enable it to exercise an important moral effect, by _threatening the flank_ of such of the enemy's troops as may be sent forward to attack. At the battle of Leipsic, in 1813, the Wurtemburg cavalry was launched against Blucher's Prussian cavalry. But, seeing the Prussians drawn up not only in front, but opposite their flank, they lost confidence, charged feebly, and too late. They were consequently repulsed and driven back on the Marine Battalion, which they threw into confusion. So, at the battle of Prairie Grove, in December, 1862, the First Iowa Cavalry, which was held in reserve, by its mere presence, caused every attempt of the rebels' flanking regiments to be abandoned. 4. In order not to impede the manoeuvres of the infantry, cavalry should not _fill intervals_ in the lines, or be placed between the lines. It is dangerous when the ground is such as to require the cavalry in the centre of the first line; for, if it is beaten, a gap is left through which the enemy may penetrate. At the battle of Blenheim, in 1704, Marlborough owed his victory, in great measure, to the Allies' forcing back the cavalry forming the centre of the French army; thus turning the whole of its right wing, and compelling the infantry posted at Blenheim to surrender. 5. Yet cavalry should always be near enough to the infantry to take immediate part in the combat; and although it should not be posted in the intervals between infantry corps, it may _debouch through them_, in order to attack more promptly. At the battle of Friedland, the Russian cavalry charged a French infantry division. Latour Maubourg's dragoons and the Dutch cuirassiers, riding through the battalion intervals, charged the Russians in turn, and drove them back on their infantry, throwing many of them into the river. 6. When _both wings are uncovered_, the best place for the cavalry will usually be in rear of the centre of the second line; whence it can be sent in the shortest time to either wing. 7. Cavalry should not be _scattered over the field_ in small detachments, but be kept massed at one or more suitable points; as behind the centre, or behind one wing, or both wings. A small cavalry force should be kept entire; or it will have very little chance of effecting any thing whatever.