2. The marksman holds his rifle in a line connecting the right shoulder, the eye and the object, hence most of the body lies to the left of the rifle. The loophole should be made to the right, with a niche in the wall of the parapet from the hip to the armpit, to bring the left shoulder well forward. It will be found that this permits the right elbow to be placed on the edge of the parapet. [Illustration: PLATE 22.—Methods of constructing loopholes with sandbags.] 3. Box loopholes with screens or blindage may be used, but should be placed by a skilled marksman. The great disadvantage is that the enemy notes these parapet alterations. Steel loophole plates are now provided for this type of loophole, As the Germans sometimes use a steel bullet with great penetrating power, it is advisable to place two plates together to insure protection. 4. With every precaution that may be taken it is difficult to conceal a loophole. A good plan is to deceive the enemy by using painted sandbags and preparing plenty of dummy loopholes. 5. The minimum width of loopholes should be 2-1/2 inches. If narrower than this, it is impossible to use both eyes to judge distances correctly. 6. The parapet should be so sloped that there is a maximum grazing fire when the rifle is fired as it lies on the parapet. To insure that the bullet will not graze the parapet, although the sights are clear, look through the barrel with the bolt removed. [Sidenote: Communication Trench] [Illustration: PLATE 23.—Type of communication trench.] In the first line fire trenches there are so many crooks and turns and the trench itself is so narrow that passage along the same is very difficult. To provide for this lateral communication a trench known as the communication or supervision trench is dug. It runs generally parallel to and a short distance in rear of the fire trench and is connected therewith by zigzag approaches. The factor that determines the distance between the fire trench and the communication trench is that it should be at such a distance that a shell bursting in one of the bays would not destroy the communication trench. The location of the communication trench with respect to the fire trench and the arrangements of the approaches is shown in detail in Plate 1. The profile of the ordinary communication trench is shown in Plate 23. [Sidenote: Dugouts] During the artillery bombardment few men are left in the fire trenches. The remainder of the garrison is held under cover a short distance to the rear. This cover is provided by a system of dugouts connected with the fire trench through underground passageways that lead to the communication trench. This arrangement is shown in Plate 1. A profile of the latest type of dugout is shown in Plate 24. The solid earth cover is from 12 to 18 feet thick, which gives protection from all but the very largest caliber shells. Effective resistance is supplied by roofing materials as follows: