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 cared for in a similar manner.
[1170]. Illumination of the Foreground. Battlefield illumination is a necessity where night attacks may be expected, and also as a protection to the line of obstacles. Portable searchlights have become an accepted part of every army. In addition to these, trenches must be supplied with reflector lights, star bombs, rockets and flares, arranged so that they can be put into action instantaneously when the enemy approaches.
The foreground should be entirely illuminated, leaving the defenders in the shadow. If the light is too close to the defenders parapet, they are illuminated and become a good target. Some flares will burn for 20 minutes and may be thrown to the front as grenades, fired as rockets, shot from small mortars, or placed well to the front to be set off by trip wires close to the ground. The best light devised is one that can be fired well to the front from a small mortar and then hung suspended from an open parachute above the enemy. Bonfires can be laid ready for lighting when no other means is at hand. Whatever form of illumination is adopted, it should withstand bad weather conditions and prolonged bombardment.
[1171]. Telephones. When armies have been forced to trench warfare and time has permitted an elaborate system of trenches to be constructed, telephone communication is established as soon as possible. The central station, with the switch-board is located in a shelter in rear of the cover trenches and lines are run to all trenches, lookout stations and listening points.
[1172]. Siege works. Comprise devices used by besiegers and besieged in attack and defense of strong fortifications and especially those devices enable troops to advance under continuous cover.