to explain in articles of this character the mysteries
of intrenchment and fortification, so that they will be comprehensible.
A few notes, however, on some of the principal terms constantly
employed, may be found useful and interesting.

_Rifle pits_--as the term is now generally used--are small embankments,
made by throwing up dirt from an excavation _inside_. They can be
erected quickly, for it will be seen that those behind them have the
advantage, not only of the height of the embankment, but also of the
depth of the ditch. Thus an excavation of two feet would give a
protection of _four_ feet. This is the ordinary rifle pit, but when time
permits it receives many improvements.

_Breastworks_ are any erections of logs, dirt, etc., raised breast high,
to shelter the men behind them.

An _abatis_ consists of obstructions placed in front of a work to form
obstacles to a storming party. The most convenient method of forming it
is to cut down trees and allow them to lie helterskelter. When there is
time, the trees are laid with the butts toward the work, and the
branches outward--the small limbs being removed, and the ends of the
remainder sharpened.

[Illustration]

A _redan_ is a letter V, with the point toward the enemy, and is used
generally to cover the heads of bridges, etc.

[Illustration]

A _lunette_ is the redan with flanking wings.

[Illustration]

A _redoubt_ is an enclosed parallelogram.

[Illustration]

These works are very imperfect, because they have exposed points. The
angles are not protected by the fire from the sides. To remedy this
difficulty, the next most usual work is the _star fort_, made in the
form of a regular or irregular star. It will be perceived that the fire
from the sides covers the angles.

The next and still more improved form of work is the bastioned fort,
which consists of projecting bastions at the corners, the fire from
which enfilades the ditches.

The following is a diagram of a vertical section of the parapet and
ditch used in all fully constructed field works:

[Illustration:

A B is the slope of the banquette.

B C head of the banquette, or place where the men stand to deliver
their fire.

C D the interior slope of the parapet.

D E superior slope of the same.

F G the berme, or place left to prevent the parapet from washing
down into the ditch.

G H the scarp or interior wall of the ditch.

H I the bo