All aircraft belonging to the enemy will be heavily fired on by machine guns and rifles as long as they are within range, but no firing will take place without the order of an officer, who will first satisfy himself that the aircraft is hostile. Directions should be given to the men as to how many lengths in front of the aeroplane aim should be taken. If a "Zeppelin" is sighted, a "priority" message will be sent to brigade H. Q. reporting the fact and stating approximately where the "Zeppelin" was seen and in what direction it was proceeding.
22. MAPS.—Maps with our own trenches marked on them will not be taken into the front-line trenches.
23. TELEPHONE MESSAGES.—No messages regarding the action of our own Artillery or other matters of an important nature will be sent by telephone to the fire trenches. Such messages will be sent by orderly. This is necessary because it has been found that the enemy has, at times, read our messages by induction.
24. SIGNALERS.—The brigade signaling section is responsible for the maintenance of communication between brigade H. Q. and battalions.
Battalion signalers are responsible for communications within the battalion.
All wires must be pinned in to the sides of trenches. Infantry wires on the S. and E. sides and Artillery wires on the N. and W. sides.
Pins for this purpose can be obtained from brigade headquarters.
All wires will be labeled with the name of the battalion at least every 50 yards.
Officers in charge of battalion signalers are responsible that all disused or unlabeled wires within their areas are reeled up.
All wires will be patroled at least once every 24 hours.