11. Platoon commanders may divide the tour of supervision of the platoon sector with the squad leaders. 12. The whole company stands to arms during the hour before dawn. [Sidenote: Observation] Observation of the enemy’s line should be continuous. The observation and firing system will be arranged so that all parts of the enemy’s line will be under observation and fire at all times. Plate 42 shows the arrangement in general. The appliances for carrying it out are shown in Plates 43, 44 and 45. [Illustration: PLATE 43.] The observation is conducted through a small loophole made by a stick through the parapet or an iron tube run through and directed toward the point to be observed. To conceal the exit a few tufts of earth and grass are placed there in an irregular manner. Steel loopholes may also be employed for observation and firing purposes. They may be arranged a yard or two apart, so that one man observing through one can direct his mate using the rifle at the other so that he may bring fire to bear upon any member of the enemy’s force that exposes himself at the point under observation. The loopholes, both observation and firing, are arranged slantwise in the parapet so that the observer does not look straight to his front nor does the firer fire in that direction. [Illustration: PLATE 44.—Observation loophole and rifle firing rack.] An aiming rack constructed so as to resist the recoil of the rifle and not derange its aim on firing may be arranged near the observation loophole. When the enemy exposes himself all that is necessary is a press on the trigger and the bullet goes straight to its mark. Such an aiming rack may be easily constructed, as shown in Plate 44. Observation of the enemy trenches may also be effected by use of the periscope or, in the absence of one of these, by a looking-glass in a slanted position fastened to a stick planted at the rear wall of the trench and protruding over the parapet, to reflect his trenches. (See Plate 45.) [Sidenote: Field Glasses] The enemy’s trench usually appears completely deserted, but on observing it through field glasses you are astonished by the details revealed. You will see, from time to time, the eye of the enemy observer who shows himself at the loophole, or any other activity that is capable of being observed from the outside. The observer watching through the field glasses will soon become so familiar with the appearance of the opposing trenches that he will be able to detect immediately any alteration in the obstacles, or changes that may be made, such as the establishment of new listening or observation posts, new sap heads, machine-gun emplacements, etc. Observers are charged especially with detecting the location of machine-gun emplacements. The examination should be so complete and detailed as to prevent their existence without their location being accurately known. [Illustration: PLATE 45.—Looking-glass periscope.]