of trench.= The usual minimum allowance of trench space
is one yard per man, although in some tests, two feet was found
sufficient for men to fire satisfactorily. Ordinarily one squad will
occupy the space between two traverses which experience has shown
should be about 15 feet apart.

=1165. Preparation of the foreground.= One of the first principles in
improving the foreground is that an enemy attacking the trenches shall
be continually exposed to fire especially in the last 400 or 500
yards. This requires a clearing of the foreground and a filling in of
depressions or leveling of cover. Dead space may be swept by fire of
trenches specially located for that purpose. Those features of the
ground which obstruct the field of fire, restrict the view, or favor
or the enemy's approach, should be removed as far as possible. On the
other hand, features which favor the concealment of the trenches or
increase the difficulty of the attack would better be left standing,
especially when it is possible to fire through or over them.

=1166. Revetments.= By a revetment we mean a facing placed against the
front or back wall of a trench to keep the earth in place.

When trenches are to be occupied for any length of time, they must be
revetted. There are many forms of revetments. Sod revetments, stakes
with brush behind them, stakes with planks, boards, or poles behind
them and a common form seen in the trenches in Europe chicken wire
with brush or canvas behind it.

=1167. Drainage.= All trenches should be dug so as to drain in case of
rain. In favorable locations the trench may be constructed to drain
automatically, by constructing it with an incline to one end. Under
ordinary circumstances dry standing has to be provided in trenches by
raising the foot level by the use of brush, boards, poles, etc.
Bailing will have to be resorted to in most cases to drain the trench.

=1168. Water Supply.= At least 1/2 a gallon of water per man per day
should be supplied. The supply is almost invariably liable to be
contaminated, therefore, it should be sterilized by boiling or by
treating. These are usually located just off from the communicating
trenches. Some form of receptacle should be used and all deposits
covered with chemicals.

=1169. Latrines.= Numerous latrines must be constructed in the
trenches' earth. These receptacles are removed from time to time and
emptied in pits dug for that purpose. Urinal cans must also be
provided and c