Do not place too many machine guns in the first line; in case of a violent bombardment they are sure to be destroyed. The object to be attained is to install the machine guns in conditions such that if the enemy penetrates our first line, by aid of his bombardment or asphyxiating gas, his infantry, as it advances, comes under the fire of machine guns echeloned previously in depth, under whose fire it must stop. It is not a matter of sweeping a wide sector, but of giving over certain strips of ground flanking fire which will cut down surely the enemy's waves when they push forward. The commander should, therefore, divide between the first line and the terrain in rear, the machine guns which he controls, organizing for each particular case a firing emplacement in accord with the surrounding ground and the purpose in view. GENERAL RULES FOR INSTALLATION. Machine gunners must under no circumstances abandon their positions. They must, when necessary, allow themselves to be surrounded and defend themselves in their place to the end. In many cases the heroism and tenacity of a few machine gunners have permitted the rapid retaking of a lost position. To provide for this resistance to a finish, the machine gun emplacements must fulfil the following conditions: 1. Be surrounded by a wire entanglement of irregular trace and as invisible as possible. 2. In the enclosure thus created having several firing emplacements, in case one or more becomes useless. 3. The personnel must have all the means for protection against gas and have in addition rations, water and abundant ammunition. EMPLOYMENT OF FIRE AND INSTRUCTION. The more grazing the fire of a machine gun the more effective it is. This causes the principal employment of the machine gun to be at distances where the trajectory is flattest, that is under 800 or 1,000 yards. However, the effort to obtain a grazing fire must not exclude long distance fire. This latter will always be justified when directed upon important objectives, or necessary points of passage. For this fire to have some efficacy, it is necessary to calculate the range with the greatest precision. On the defensive indirect fire will be employed sometimes to annoy the supply, reliefs, etc. To give results, great quantities of ammunition will have to be expended. All of the officers and non-commissioned officers and as many men as possible must be capable of firing the machine gun, so that at the time of an attack no gun will remain idle for want of personnel. It is, moreover, essential to keep up the training of the personnel by having them fire at least twice a month, and, if possible, once a week. RESUME. Machine guns must be utilized in the greatest measure in order to _economize the infantry._ Seek to employ them always in a, _flank fire_. Conceal them so as to get _surprise fire_. _Echelon_ them and _shelter_ them so as to avoid their premature destruction. POINTS BEFORE FIRING.