2. Revettment work not well anchored. In some cases too many wires from supports fastened to one dead man. Another fault is that dead men were not buried deeply enough in the ground, nor far enough back from the trench. In one case a dead man (a stake) supported all four sides of an island in a communication trench. The destruction of this post would have completely blocked every passage around the island. Furthermore, dead men rot quickly and tend to break off. It is necessary, therefore, to have a number of them, each holding only a portion of the weight. All projecting branches and irregularities along a trench should be removed by occupying troops. 3. Too many loop-holes. Except for snipers, riflemen and automatic riflemen fire over the parapet. 4. Machine gun loop-holes not wide enough. They should not be less than 36 inches wide. There must be vegetation planted in front and a curtain hung over the loop-holes to prevent detection. The growing plants in front will be easily swept away at the first discharge. 5. Remember never to imitate shell-holes until after a real bombardment by the enemy. 6. The dugouts made were never deep enough and afforded no protection. In fact it would be far better to have none than to be caught inside when a shell exploded in a shallow one, because the confinement of the explosion would intensify the effect. 7. Shelters were all too wide. Six feet is the maximum. The platoon headquarters dugout should be of the same width as the trench, not over three feet, but as long as necessary. Company headquarters is six feet wide and of whatever depth required. 8. In digging, not enough care was used to conceal the fresh earth from the enemy. Make false emplacements to utilize this dirt; also dig dummy trenches about one foot deep, leaving the sides sharp so that they will show clearly on aerial photographs. 9. In using plants as camouflage, distinct care must be exercised not to put growing plants too freely nor to place them where they never existed. The actual ground conditions must be copied. 10. Some latrines were not arranged with the stools close beneath the wall nearest the enemy. This caused the loss of protection, which it is imperative to consider, as many casualties occur here. 11. Too many listening posts. They are easily captured by hostile fighting patrols. There should never be more than two listening posts to a battalion. 12. The observation stations in many instances had no good field of fire or were outlined against the sky on the crest of some rise. The site for an observation post should always be placed over the crest and have a good field of fire for use in case of attack. Occupation. I. Relief in the Trenches.