This rule is an important one, and should never be neglected.
It may also be laid down as a maxim, in the formation of cavalry on the battle-field, that the first line after the charge, even if most successful, may require reforming in rear of the second line, and that this last should be prepared to act in the front line after the first onset.

The success of the battle frequently depends upon the charge of the final reserve of cavalry on the flanks of lines already engaged.
It is on account of this frequent manoeuvring of the cavalry on the battle-field, its reforming for repeated charges, that great bodies deployed in full lines are principally objected to.

They cannot be handled with the facility and rapidity of columns of regiments by divisions.

The attack of Nansouty's cavalry, formed in this way, on the Prussian cavalry, deployed in advance of Chateau-Thierry, in 1814, is a good proof of this.
Cavalry may be brought to a charge--1st, in columns; 2d, in line; and 3d, in route, or at random, _( a la deban-dade.)_ These may also be varied by charging either at a trot or a gallop.

All these modes have been employed with success.