2. To properly prosecute attrition of the enemy’s works. =Attrition.= By the word attrition in fighting is meant the gradual destruction of the enemy’s morale and strength, and demolition, little by little, of the enemy’s position. Trench warfare is not a rest or simply a time for guard duty. It is a phase of the battle in which you must do as much damage to the enemy as possible. This work will also keep up the offensive spirit. For this purpose different means are used: (_a_) Sniping: Each company in the first line uses its best shots as snipers. A sniper must be a good observer and he must depend upon his keen eye for evidences of the enemy, such as smoke of cigarette or the glint of a bayonet, giving proof of the presence of an enemy. Especially during hostile shelling will a too curious enemy come to his loopholes to observe the effect of the same. This is the sniper’s chance. In each center of resistance the snipers are placed under the command of a sniping officer. He makes the rounds of the snipers’ posts once or twice a day, and submits a daily report containing known casualties of the enemy, location of the number of snipers’ posts, telescope rifles, fixed rifles, and rifle batteries. (_b_) Infantry Weapons: Besides sniping, all the other infantry weapons are used to assist attrition of the enemy. Hand and rifle grenades are thrown on special points of the hostile line. A battery of hand or rifle grenadiers properly disposed can very often carry out a concentrated surprise fire on an enemy’s salient or advanced post. Automatic and machine guns are always used for this purpose and especially at night. They are trained on supply routes, road junctions, etc., and by use of sudden bursts of fire at irregular intervals they will compel the enemy’s supply parties to continue their transportation in the boyaux instead of on the open ground. The use of indirect machine gun fire is very depressing to the enemy. Such judicious employment of machine guns is sometimes more effective than severe artillery shelling. The 37 mm. gun, which is also an infantry weapon, is used principally against hostile machine gun emplacements. The location of this gun must be constantly changed. (_c_) Use of Artillery Weapons: Besides furnishing barrage fire against hostile attacks, the artillery can be called upon for surprise fire on working parties, harassing fire during the night against supply parties and their routes, and also for reply fire against hostile shelling. Trench mortars and other engines keep the enemy as uncomfortable as possible at all times. (_d_) Fighting Patrols and Raids: Fighting patrols and raids are used with the express purpose of causing loss and damage to the enemy. This is accomplished by engaging the enemy’s patrol and working parties or by raiding his saps, listening posts, or trenches. Such operations must not, however, degenerate into frivolous local fighting, causing loss of men and waste of artillery ammunition.