1. Allocation of front. (The front of an American battalion will average about 1,000 yards.) Diagrams: A. The Regiment. B. The Battalion. C. The Company. D. The Platoon. 2. Distribution of effectives. Determined chiefly by the terrain and by 3. 3. Employment of the several arms: (a) Machine guns. Crew of 8 men per gun. (Furnished by detachments of a machine gun company.) Located by the infantry commander, in concealed emplacements behind the first line, to deliver successive barrages from flanking positions. Effective range: up to 700 yards. (b) Automatic rifles. Crew of 3 men per rifle. Usually posted to enfilade the entanglements of the first line. They concentrate the fire effect of from 7 to 10 riflemen. Effective range: up to 300 yards. (c) Rifle Grenadiers. Located near enough to first line to hold the enemy trenches under fire and deliver effective barrages near the mouths of our own communicating trenches. Should be located near observation posts so that their fire can be promptly corrected. (d) Trench mortars. Located similarly to (c). Manned by riflemen. (e) Bombers. One supply man to each 2 grenadiers. Used for protection of auto-rifles, in counter attacks, for protection of communicating trenches and fighting in close quarters. (f) Riflemen. Posted to deliver frontal fire. Grouped according to the plan of counter attacks. (g) As many men as possible should be instructed in the use of the enemy's weapons. D. LIAISON: (a) By telephone. Quickest and most accurate. Maintained between each platoon and its company headquarters, and between adjoining companies. Especially subject to destruction in bombardment. Wireless and ground telegraphy are used only between brigade and division headquarters. (b) By runners ("liaison agents"). Five detailed from each company to battalion headquarters; one sent to each adjoining company headquarters; one from each platoon to company headquarters; four or five on duty at each platoon headquarters; five from each machine gun company to battalion headquarters. Messages sent by them should, if practicable, be written and signed, and should be receipted for by the addressee. (c) By rockets and flares. Quickest means of liaison with the artillery in rear. (d) Domestic (message carrying) grenades. (e) Dogs and carrier pigeons. Sent out to the rear from battalion headquarters. (f) One searchlight--with a radius of 3 miles--is furnished to each company. (g) Noise. Klaxon signals, etc., give warning of gas attacks. E. OBSERVATION: