retreat is very powerful, as
it keeps the enemy constantly _at a distance_.

A fine example of the use of it for this purpose occurred just before
the battle of Pea Ridge, in March, 1862. A rear-guard of six hundred
men, under General Sigel, was retreating before a force of four
regiments of infantry and cavalry, that followed and attacked it on
every side. Sigel disposed his guns in echelons, the one of which
nearest the enemy played on his attacking squadrons with grape and
shell, which suddenly checked them. Instantly profiting by their
temporary hesitation, the echelon limbered up and galloped away to
another position, while the next echelon, again checking the enemy by
its fire, followed its example. By this means, Sigel, cutting his way
through a vastly superior force, succeeded, after a retreat of ten
miles, in rejoining the main body with but trifling loss.

9. If driven to the last extremity, the gunners should try, at least, to
_save the horses_, and to blow up the caissons they have to abandon.

At the battle of La Rothiere, in 1814, where Napoleon, with thirty-two
thousand men, was overwhelmed by one hundred thousand Allies, and was
obliged to leave fifty guns on the field, he succeeded in bringing off
all his gunners and horses.

D. AGAINST INFANTRY.

1. It is an important rule that artillery should play on the enemy's
_troops_, without attending to his batteries, except in urgent cases.

2. Against a _deployed line_, whether marching by the front or by a
flank, case-shot, that is, grape, canister, and spherical case
(sometimes called _shrapnel_), are most suitable; as these all scatter,
right and left, to a considerable distance.

The best effect of canister is within two hundred yards. Beyond three
hundred and fifty yards, it should not be used.

The best effect of grape is within four hundred yards. Over six hundred
yards, it is not very effective.

Spherical case is effective at much greater distances, its range being
nearly equal to that of solid shot.

Against a line of infantry at a greater distance than six hundred yards,
spherical case should be used, chiefly, if not exclusively; as being
more likely to be effective than ball.

3. But case-shot are _unsuitable against a column_, as they consist of a
number of small balls which have not momentum enough to penetrate into
it to any depth. When the enemy advances in columns, solid shot should
plough through them from head to rear, a cro