At night, one sentinel is posted, say, for example, every 10 yards in the fire trench of the first line. During the day, only enough sentinels are posted so that all parts of “No Man’s Land” can be observed. This will allow a maximum number of men to rest. In the firing line, the sentinels work in three reliefs. When not on guard duty, they sleep. The remainder of the garrison in the cover trench, however, are available for work, for patrols, and to furnish supply parties. Sentinels should have their rifles resting on the parapet close at hand, ready to fire at a moment’s notice. By day, the sentinels use a periscope or observe through a loophole. This practice is, however, strictly prohibited at night, when a, sentinel must observe over the parapet. As little challenging as possible is done, and then only in a very low tone. =Reconnoitering Patrols= are the best means for security against attack. Every night the commanders of the support points or the centers of resistance send out patrols in front of the firing line. The strength of a patrol must be sufficient to carry back a wounded man, _i. e._, the number should be five, six, or more. The success of a patrol depends entirely upon the leader. He must be clever, daring, and observant, and the rest of the patrol is simply his bodyguard. He himself must observe the objective of the mission of the patrol. Patrols should never be sent out without definite orders as to their mission. Such may be, for example, a reconnaissance of the enemy’s lines, to discover if the enemy has cut passages in his wire belt preparatory to an attack, to examine their own wire entanglements, etc. The route of the patrol must be exactly determined; also the hour of departure and return designated. Word is passed along the line of sentinels that a patrol is out in front with the necessary information about the same. The preparation for a night patrol must be made during daylight. =Officer of the Watch.= In the firing line the company commander arranges a roster of his officers for duty as officer of the watch. Also in each platoon the platoon commander will detail a N. C. O. of the watch. The officer of the watch is responsible for the duties of observation and security, and is especially responsible for the giving of the alarm in case of an attack and consequently for the calling of the artillery barrage by use of rockets, signals, etc. =Standing to Arms.= It is of the greatest importance that the troops in the first line are thoroughly trained in taking their positions when the alarm is given as quickly as possible, without confusion. The alarm is often given for practice in order to ascertain the amount of time it will take the men to reach their places in the firing line. The command “Stand to” is usually given one hour before daylight and one hour before dark. At this time the company commanders arrange for inspection of arms, ammunition, and equipment by the platoon commanders.