When a valley or dip is close to the side of a C. T. a few narrow gullies through the side, of about 18 inches in width, should be made so that liquid mud can be swept along the trench and on through the gulley to a natural fall. These little gullies or ditches should start at a place or places where there are dips in the level of the trench and must be dug straight through the side, as it then becomes easier to keep clear and gives no obstruction to the flow of mud; but if facing the enemy, it should not be in a straight line, as it then allows rifle fire into the trenches. If no other way is possible, then overhead traverse or other means of protection should be taken at that point. Sometimes, when it is not possible to complete these gullies, they should be dug out as far as circumstances will permit and a block of soil or very large sods be put at the junction of the gulley to the trench and the liquid mud dipped out of the trench and dumped into the gulley, where it will be prevented from running into the trench again by these collections of sods. This process is very slow, but conditions frequently make it the easiest and most convenient way of ridding the trenches of some of the mud. This work can be carried on by what is sometimes known as a “trench patrol” or maintenance squad, which is generally detailed from the company in the support line and which patrols the system of trenches held by their battalion during the day. The N. C. O. in charge generally reports serious collapses to his company officer, who in turn reports it to the engineers, who immediately take steps to have it repaired. The width of drainage gullies should not be less than 18 inches, thus allowing easy use of brushes issued. With these brushes and adequate gullies, very long stretches of trench can be kept in excellent condition when the trench is wide enough to allow the drying effect of wind and sun to reach the bottom. The time spent in making these gullies is saved over and over again. If there be no natural valley or dip, a sump-pit is generally dug, the size depending on the energy of the troops digging it, but generally it is about 10 feet below the level of the trench it drains, and anything from 8 feet on in diameter. It is dug some fair distance from the trenches and in a position that will allow the maximum amount of gullies to be led to it from that particular section of the trench. After having this system worked out, the next thing is to ascertain what parts of the rest of the trench system will not be affected by this drainage, and there to dig similar sump-pits just to the side of the trenches drained, small gullies leading to them. These need only be about 6 feet deep below the trench level and 4 feet in diameter. A short gulley, 12 to 15 inches wide and 2 feet long, should lead from the trench to the sump-pit, as shown in sketch of trench system.