eserve. Each corps or division acts by itself, with its infantry,
cavalry, artillery, and engineer troops. The reserve of cavalry may be
formed in rear of the centre or one of the wings. In small forces of
fifty or sixty thousand men, the cavalry may act with advantage on the
wings, in the manner of the ancients. If the reserve of this arm be
large enough to form three separate bodies, it may _itself_ very
properly be formed into a centre and wings. If it be formed into two
columns only, they may be placed in rear of the openings between the
centre and the wings of the main force. The reserve of artillery is
employed either to reinforce the centre or a wing, and in the defensive
is frequently distributed throughout the whole line of battle. In
offensive operations, it may be well to concentrate as much fire as
possible on the intended point of attack. The mounted artillery either
acts in concert with the cavalry, of is used to reinforce that arm; the
light-foot acts with the infantry, and the batteries of heavy calibre
are distributed along the line, or concentrated on some important point
where their fire may be most effectual. They reach the enemy's forces at
a distance, and arrest the impulsion of his attack. They may also be
employed to draw the fire of his artillery; but their movements are too
slow and difficult for a reserve.

The order of succession in which the different arms are engaged in a
battle, depends upon the nature of the ground and other accidental
circumstances, and cannot be determined by any fixed rules. The
following, however, is most frequently employed, and in ordinary cases
may be deemed good.

The attack is first opened by a cannonade; light troops are sent forward
to annoy the enemy, and, if possible, to pick off his artillerists. The
main body then advances in two lines: the first displays itself in line
as it arrives nearly within the range of grape-shot; the second line
remains in columns of attack formed of battalions by division, at a
distance from the first sufficient to be beyond the reach of the enemy's
musketry, but near enough to support the first line, or to cover it, if
driven back. The artillery, in the mean time, concentrates its fire on
some weak point to open a way for the reserve, which rushes into the
opening and takes the enemy in flank and rear. The cavalry charges at
the opportune moment on the flank of the enemy's columns or penetrates
an opening in his line, and cuttin