to 50 yards in rear of the fire
trenches. These trenches furnish shelter for at least 2/3 of the
firing line and supports.

[Illustration: Fig. 36]

[Illustration: Fig. 37]

[Illustration: Fig. 38]

The reserves are furnished yet more elaborate shelter, with plenty of
room for the men to lie down and rest and when practicable, bathing
facilities are provided.

=1156. Dugouts.= An elaborate system of dugouts has developed along
the lines occupied by the troops in the European war. These dugouts
are located from 14 to 40 feet below the ground and are reached by
stairs in timbered passage ways. At the foot of the stairs a tunnel or
corridor runs forward and on either side or at the end, rooms have
been dug out varying in size. Most of these rooms have been timbered
and lined. Many are electrically lighted. In some of these underground
shelters, accommodations for several hundred men have been prepared
with all of the necessary facilities for making them comfortable. It
must be understood that such elaborate preparations can only be made
when troops face each other in trenches where operations have
developed into practically a siege.

=1157. Communicating trenches.= These trenches as the name implies are
for the purpose of providing safe communication between the cover and
fire trenches. They may be also constructed just in rear of a series
of fire trenches to provide a means of communication from one to the
other. Communicating trenches also extend to the rear of the cover
trenches and provide safe passage to fresh troops or supplies. These
trenches are usually laid out in zig zag or curved lines (Fig. 39), to
prevent enfilade fire from sweeping them. As a general rule excavated
earth is placed on both sides of the trench to afford protection, the
depth is usually from 6 to 7 feet. (Fig. 15) shows a typical
communicating trench.

[Illustration: Fig. 39

_Typical Passage Trench from Supports to Firing Line._

(From _Field Entrenchments_--Solano)]

=1158. Lookouts.= To enable the garrison of a trench to get the
greatest amount of comfort and rest, a _lookout_ should be constructed
and a sentinel stationed therein.

The simplest form would consist of two sandbags placed on the parapet
and splayed so as to give the required view, and carefully concealed.

Better forms may be constructed, with one side resting on the berm by
using short uprights with overhead cover, a slit on all sides being
provided for obser