d
be that of a very strong box, so that it will stand strain, if
necessary, from within as well as from without.

Depots for Supplies must be near the headquarters of the platoon,
company, battalion and regiment. Shelters may be made with ammunition
boxes set into the side of the trench. Places should be provided for
the following: Food, ammunition for rifles and auto-rifles, grenades,
rockets, tools and other supplies. Places must also be arranged in
the front line for ammunition, rockets and hand and rifle grenades.

Telephones. Communication is established as speedily as possible
with the various units. In the forward trenches wires do not last long
under bombardment and fire left open along the side of the trench,
where quick repairs can be made. All soldiers must be taught to
respect these wires and to care for them when they are found under
foot or hanging. Conduits are dug for wires to battalion and
regimental headquarters, and these are fairly safe from shell fire.

Departure Parallel. In preparing for an advance upon the enemy, a
straight line trench without traverses, and with steps at the end for
exit to the surface, is built in front of the first line trench. This
line of departure is generally brought within about 200 yards of the
hostile line by means of _saps_, short trenches run out from the front
line to the new parallel. Since this line of departure can be seen by
the enemy, it is sometimes better to construct steps in the front line
trench itself, or when possible to build a _Russian sap_. This is a
tunnel very near the ground, which can be broken through at a moment's
notice when troops are ready to advance.

Machine Gun Emplacements.--Shell-holes with a good field of fire and
emplacements along boyaux are the best location for machine guns. Few
guns are placed in the front line, and these only at strong points in
the line, which command a maximum field of effectiveness. Shell-holes
may be imitated for machine gun emplacements, but in any case they
should be connected by underground passage with the trenches. Thus
when trenches are destroyed by bombardment the machine guns remain
intact. The field of fire for each machine gun should be carefully
determined and marked by three stakes, one for the position of the
gun, the other two for the limits of the field of fire. Using these as
guides, the gun can be fired correctly at night. During the day it
is never left in place nor fired from its