Disregarding for the time being the claims of protection and only considering rapid transit, there are these things to be considered: First, that a C. T. be as short as possible, making use of contours, sunken roads and other natural features to avoid digging as much as possible. Second, that a C. T. be as straight as possible, which not only shortens the distance but avoids turns and corners which interfere with speed and which require renewed effort at every turn. These sharp corners and turns must always be avoided. This can be done without weakening a trench or increasing the risk, and every effort should be made to save troops carrying full equipment, stores, ammunition, or rations from unnecessary tiring, hindrances, and difficulties, such as sharp corners and turns. Third, the C. T. J.’s must be as level as possible, as they are generally slippery, and inclines or declines should be avoided as they very often cause accidents. A longer C. T. following around natural contours is frequently more advantageous for this reason than a straight one over a hill, which it is only possible to make level by an amount of digging out of proportion to the result gained. The C. T. must be wide enough for requirements. These differ according (a) to the proximity of C. T. to the fire-trenches, (b) to the number of C. T.’s available, and (c) to the use for which a C. T. is required, i. e., whether a double C. T. (for both up and down traffic) or a single C. T. (for traffic in one direction only). When a C. T. is close to the fire-trench, troops moving into it are practically themselves in the fire-trench and as each group has probably to get to a different part of that fire-trench, all necessary traffic up and down the fire-trench and disturbance of the men occupying it must be avoided. Rapid transit can advantageously be obtained by other means than the width of the C. T.; by dividing the single C. T. at some point from 30 to 60 yards in rear of the actual fire-trench into a number of small narrow C. T.’s, each leading to a group of 3 to 6 fire-bays, and these may again be divided into those for up and those for down traffic. This system requires a fair amount of thinking out and all the trenches should be plainly marked and named. These names are placed on notice boards at the different junctions having the proper indications and rules directing the use of up and down traffic. This is and should be rigidly enforced during both quiet and active periods, but takes on a much greater importance during active periods.