Automatic rifles, rifle grenades and hand grenades are used to constitute a barrage to keep back the enemy. The entire front should be defended by a barrage of hand grenades, while the barrage of automatic rifles and rifle grenades is superposed farther to the front, up to 400 yards.
All riflemen and those grenadiers not employed in forming barrages are reserved to make a counterattack.
Companies on the second line operate on similar principles; machine guns, automatic rifles and rifle grenades are arranged so as to cover every portion of the first line that might be invaded. After a short preparation by fire from these, the grenadiers and riflemen make the counterattack.
The captains in charge of the two lines are responsible for the arrangement of the machine guns, automatic rifles and rifle grenades, the distribution of barrages and the distribution of groups for the counterattack. The real strength of the defense consists, not in holding the fire and cover trenches, nor even the support trenches, but in holding the supporting and strong points until the counterattack can be launched.
Liaison.—The question of liaison in battle is of the utmost importance, and complete co-ordination of the different arms is absolutely necessary. Each battalion sends an officer or non-commissioned officer and a cyclist to the colonel, and each colonel sends a soldier to the battalion commander.
The principal means of communication are the telephone, telegraph, wireless, aeroplane, mounted messengers, autos and motorcycles; and at the front runners, visual signals, rockets and carrier pigeons.
Each battalion commander is connected by telephone with each company commander, with the artillery observers, with the artillery commander, with his own colonel and with the adjacent battalions on either side.
The signallers of assaulting companies move with the company commander. All signallers should be given a special training in repeating a message several times to a known back station which may not be able to reply forward.
At the commencement of the assault the pigeons and pigeon carriers must be kept back at battalion headquarters, and sent forward as soon as the position has been gained.
Runners can be relied upon when all other means fail. They must be trained with their companies. Runners should be lightly equipped and wear a distinctive mark. They must be familiar with all the principal routes to all the principal centers within their battalion sector. The quicker they go the safer they are. Company and platoon runners must go forward with their respective commanders. Messages to be carried long distances will be relayed. Never send a verbal message by a runner; ignore any received; all messages must be written.