[1]: This chapter reprinted from _Infantry Journal_.
_A screen or mask_ consists of hedges, crops, underbrush, etc., which hide the rifleman without, however, protecting him from fire.
_Cover or shelter_ consists of walls, earthworks, etc., which protect the rifleman from fire.
On the battlefield, natural features that screen and shelter should be utilized as much as possible, as they possess the following advantages over artificial works:
(_a_) Their organization demands less work.
(_c_) From their nature, it is difficult for the enemy to estimate, for a given length, the number of men sheltered.
They possess, however, certain disadvantages:
(_a_) The protection is sometimes so excellent that, morally as well as materially, it becomes difficult to leave the shelter. Example: quarries with obstructed exits. Therefore, good judgment must be exercised in the selection.
(_b_) Some of them are too visible. Example: large hedges. In this case their range can be easily found.
As a general rule, do not occupy them uniformly and do not change the appearance of the organized parts.
To organize the cover which protects troops from fire, construct suitable positions for firing and resting. To utilize the screens which merely hide the troops without protecting them from fire, dig trenches behind these screens in the following manner:
(_a_) Choose the points which give the best field of fire.
The constructions are usually “individual” in the first period of work; afterwards, they are organized “collectively.” The covers are: (1) for riflemen lying down, (2) for riflemen sitting down, and (3) for riflemen standing up.
Examples of hasty individual cover behind trees, bushes, or branches:
(_a_) Fallen tree (logs or branches), the height of which is at a maximum of 1 foot above the ground:
[Illustration: PLATE 27a.—Use of the cover without improvement.]
(_b_) Fallen tree, the top of which is more than 1 foot above the ground.
[Illustration: PLATE 27e.—Second period.]
Wood which does not afford sufficient protection against bullets must be reinforced by earth at the right and against the cover 1 foot behind. Plates 27d, 27e, and 27f show the progressive improvement of the cover.
[Illustration: PLATE 27g.—Sharp ridges, furrows, or top of a crest at the end of a gentle slope.]