affords fair cover for troops subjected to fire, but not
actually firing. When it is probable that time will permit
elaboration, the simple trench should be planned with a view to
developing it ultimately into a more complete form. (Figs. 2 and 3.)
Devices should be added to increase the security of the trench and the
comfort of the men.

Where the excavated earth is easily removed, a fire trench without
parapet may be the one best suited to the soil and other conditions
affecting the choice of profile. (Fig. 4.) The enemy's infantry, as
well as his artillery, will generally have great difficulty in seeing
this type of trench.

In very difficult soil, if the time is short, it may be necessary to
dig a wider, shallower trench with a higher parapet.

[Illustration: Plate V.]

Head cover, notches, and loop holes are of value to troops when
firing, but many forms weaken and disclose the location of the
parapet. Filled sandbags kept in the trench when the men are not
firing may be thrown on the parapet to form notches or loopholes when
the troops in the trench open fire and concealment of the trench is no
longer necessary or possible.

By the use of observation stations the maximum rest and security is
afforded the troops. Stations are best located in the angles of
traverses or at the end of the trench.

591. Where the nature of the position makes it advisable to construct
traverses at regular intervals it is generally best to construct a
section of trench for each squad, with traverses between squads. (Fig.
5.)

592. _Cover trenches_ are placed as closely as practicable to their
respective fire trenches. Where natural cover is not available, each
fire trench should have artificial cover in rear for its
support--either a cover trench of its own or one in common with an
adjoining fire trench.

The cover trench is simple and rectangular in profile. Concealment is
indispensable. It is generally concealed by the contour of the ground
or by natural features, but to guard against hostile searching fire
overhead cover is frequently advisable.

Cover trenches should be made as comfortable as possible. It will
often be advisable to make them extensive enough to provide cooking
and resting facilities for the garrisons of the corresponding fire
trenches.

593. _Communicating trenches_ are frequently necessary in order to
connect fire trenches with their corresponding cover trenches where
natural, covered communication i