Rifles must be kept clean and in good condition while in the trenches. They will be cleaned every morning during an hour appointed by the company commander for the purpose. Platoon commanders will be responsible that section commanders superintend this work. All rifles except those used by sentries are to be kept in racks during the day. Trenches must be kept in sanitary condition. Platoon commanders will be responsible for the latrines in their sections of the trenches. All water for drinking and cooking is to be taken from a water cart or tank provided for this purpose. Stretcher bearers will be stationed at a place designated by the commanding officer. No soldier will be buried nearer than 300 yards from the trenches. In every platoon a non-commissioned officer will be detailed for duty by day; he will do no night duty. He will post the day sentries and see that they are on the alert and carry out their orders correctly. He will be responsible for the cleanliness of his lines and will frequently visit the latrines. He will see that all loose ammunition is collected. The platoon commander will always send a non-commissioned officer to draw rations and he will be responsible for their delivery. The passing along of messages by word of mouth will not be used. All messages should be written. Special instructions will be issued as to precautions against gas. Selection of Site. (a) Fire trench should be selected with due regard to tactical requirements and the economy of men. (b) Every fire trench should have a good field of fire, at least 250 yards. (c) The trenches should have the best possible cover. (d) The forward position on a slope for the first line has the best advantage. The support trench should be on the reverse slope from 100 to 600 yards in rear of the first line to prevent direct observation and to be practically free from artillery fire. The reserve trench is usually from 1/2 to 1 mile in rear of the first line. Remember that the first line, the support line, and the reserve line are all fire trenches. Do not put them on a crest. (e) The communicating trenches (boyaux) should be zigzagged, wide and deep, and should follow the low ground. The longest straight trench should not exceed thirty paces. The angle made by each turn should be less than 140 degrees. (f) The fire trenches should have salients and re-entrants so as to flank the wire entanglements. The bays are usually 27 feet long with 9 feet of traverse. (g) There are two problems in the siting of trenches, one for those to be constructed under fire and another for those that will be constructed without any danger from fire. Trenches built under fire are usually made by connecting up individual shelters made by the front line when forced to halt. Trenches built under quiet conditions can be laid out according to the best possible plan. Trench Construction.