If the enemy is close, sentries should be supplied with a small periscope to fix on sticks or bayonets. Magazines must be kept as full as possible. Sentries are not allowed to look over the parapet by day, but by night they must keep a continuous lookout. Shots should be fired even when no lights are showing, on the chance of catching hostile patrols or working parties. The best time to watch across No Man’s Land is exactly the minute that the enemy send up a Very light, as there is little danger of one being seen, the real danger coming when the Very light is coming down behind you. Sentries should not reply to bursts of rapid fire on the right or left, unless they have a definite object to fire at.

Arrangements are usually made for commanders of two or three neighboring platoons to divide the night between 10 P.M. and the time for “Standing to” between them. The platoon commander on duty in each watch should patrol the line constantly and satisfy himself that the proper number of sentries are on duty and keeping a sufficient lookout; also that they have good firing positions. In each platoon the sergeant and section commanders keep watch similarly in turns during the night, and are responsible for the relief of sentries. They also visit sentries every hour.

It is a rule which must be strongly enforced, that every sentry must challenge each person passing him, as it has often happened that enemy officers with more daring than common sense and speaking fluent English, have come into the trenches and walked up and down without being molested, which was only made possible by sentries not challenging every one passing his post.