Several emplacements should be provided so that mortars, etc., may be removed as soon as they have obtained desired results or been located by the enemy. The trench mortar commander should make it his business to study carefully all possibilities for effective emplacements and should inspire his men to be alert and quick to improve opportunities. 80.--Use of machine guns. The machine guns should likewise be handled as a mobile weapon and not be used merely from elaborate carefully concealed emplacements commanding otherwise uncovered ground or enfilading communication trenches, etc.[C] 81.--Use of hand grenades. Hand grenades may be listed as trench artillery. The temptation is to use them too freely. Like other ammunition they should never be wasted and always used with a definite aim. FOOTNOTE: [C] Captain Hanguillart treats this important subject very summarily. Cf. Cole & Schoonmaker's Military Instructor's Manual p. 319. He also barely mentions Gas attacks. Cf. very complete treatment in same work, p. 356 to 370. FIELD ARTILLERY COOPERATION. 82.--Communications with the artillery. Should be permanent so that it may cooperate whether to repulse an enemy's attack, to silence his artillery, to damage his defences or to prepare and protect an attack or a counter attack. 83.--Observations posts. To avoid a waste of ammunition, and attain the desired result as well as to prevent the artillery fire from falling short upon one's own trenches, artillery observation posts should be provided in the fire trench or at one of the outposts. 84.--Artillery fire falling short. In case artillery fire does fall short upon one's own trenches, communicate at once with artillery commander and proceed as when bombarded by enemy. (Cf. 69 ff.) 85.--Artillery preparation of infantry attack. Special caution should be exercised in the case of a raid against the enemy's trench. Make sure that the artillery preparation has secured the desired result. Synchronize carefully the infantry advance and the lengthening of the artillery fire. DAILY SCHEDULE. 86.--Rosters and schedules. Throughout the stay in the trenches, the various fatigues should be assigned by roster and carried out according to schedule. The following schedule has been found practical: 7 A.M. (6 A.M. in summer). 87.--Cleaning of trenches. Have trenches cleaned of all rubbish, latrines disinfected, drinking water supplied. 88.--Collecting of broken equipment. All cartridge shells, broken tools, etc. should be collected. 89.--Requisition Report. A list of the supplies and ammunition needed should be drawn up. 90.--Report on night activities. Full report should be brought to the company commander, covering the work of the patrols and of the fatigue parties, and giving full details of all that has happened during the night. 91.--Report on casualties. Also the list of casualties in the last twelve hours with full names and nature of wound if possible.