are similar for the two types.

Dugouts are chambers tunnelled into the ground with twenty feet or
more of undisturbed earth above them. They are used in the cover
trenches and sometimes in the first line. Enough of them must be built
to shelter the garrison of each sector, allowing one man per yard of
front. They must also be built for machine gun and trench mortar
detachments.

Sentries must be stationed in observation posts which command the
ground in front of each dugout. They must be connected with the
dugouts by telephone or speaking tube.

Position.--Dugouts must always be on the side of the trench toward
the enemy. This prevents flying shells from falling into the
entrances. They should connect with lateral trenches, not with boyaux,
as men at the entrance obstruct traffic through the boyaux.

Entrances and exits must be well concealed, with not less than five
feet of head cover. This should be provided with a bursting layer. All
dugouts must have at least two openings, one on the opposite side of
the traverse or angle from the other. It is well to have an exit
behind the parados leading to a surprise position for a machine gun
and bombers. All openings must have a sill 6 inches to 8 inches high,
to prevent water from entering the dugout.

Galleries leading to dugouts should be built at an incline of 45
degrees. Their dimensions should be 2 feet 6 inches by 6 feet. Frames
are of squared timber. The sill and two side posts should be not less
than 6 inches square, and the frames in the passageways 2 feet 6
inches by 4 feet 6 inches. They must be placed at right angles to the
slope of the gallery, with distance pieces between uprights. In
treacherous soil the frames rest on sills. Steps in the passageway are
1 foot broad and 1 foot high.

Bomb-traps, extensions of the gallery about 3 feet long, should be
dug beyond the point where the entrance to the dugout chamber leads
off from the gallery. These will catch bombs thrown in from the
surface and protect the chamber from the effects of their explosion.

Interior. The standard section is 6 feet by 8 feet, to allow for
bunks on each side. Frames of 6 by 6 timber spaced 2 feet 6 inches
apart support the sides and roof. Roof planking should be 2 inches
thick, and the sides should be covered with 1-1/2 inch plank or
corrugated iron. Two shovels and two picks for emergencies should
always be kept in each dugout. The construction of the chamber shoul