The Archduke Charles, in speaking of cavalry, recommends that it should
be brought in mass upon a decisive point, when the moment for employing
it arrives; that is to say, when it can attack with a certainty of
success. As the rapidity of its movement enables cavalry to act along
the whole line in the same day, the general who commands it should
keep it together as much as possible, and avoid dividing it into many
detachments. When the nature of the ground admits of cavalry being
employed on all points of the line, it is desirable to form it in
column behind the infantry, and in a position whence it may be easily
directed wherever it is required. If cavalry is intended to cover a
position, it should be placed sufficiently in the rear to meet at full
speed any advance of troops coming to attack that position. If it is
destined to cover the flank of the infantry, it should, for the same
reason, be placed directly behind it. As the object of cavalry is
purely offensive, it should be a rule to form it at such a distance
only from the point of collision as to enable it to acquire its utmost
impulse, and arrive at the top of its speed into action. With respect
to the cavalry reserve, this should only be employed at the end of a
battle, either to render the success more decisive, or to cover the
retreat. Napoleon remarks that, at the battle of Waterloo, the cavalry
of the guard which composed the reserve, was engaged against his
orders. He complains of having been deprived from five o’clock of the
use of this reserve, which, when well employed, had so often insured
him the victory.