As the days go by, every effort must be made to improve the trenches. This can be done in many ways, some of which will be obvious. The front line is, of course, the most important one, and the greatest amount of work has to be done there. But support and reserve lines as well must be constructed and many communicating trenches. Support lines were usually dug at a distance of thirty to eighty yards from the firing line. In them we kept a few men to be used in case of emergency. This line was an exact duplicate of the front line and was intended to be used in case we were pushed back. The reserve line was about five to eight hundred yards back from the front line and was not brought to any very great degree of completion. Interspersed between these three lines were many redoubts, or especially strong points containing machine guns, etc., whose defenders were expected to hold on to the very last and take advantage of their more secure position to make the attacker pay dearly for his advance. All these lines had to be linked up by communicating trenches, which started about a mile in the rear of the front line and went up in zigzag lines to the latter position, crossing the other trenches on their way. These communicating trenches are used for the purpose of bringing up troops and supplies, etc., and for taking to the rear the men that have been wounded. It is usually arranged to have some of these trenches "Up" and some of them "Down" roads. Each line of trenches (except of course the "communicating") contain dugouts for the use of the troops that hold them. The distance between the communicating trenches varies from twenty-five yards to three or four hundred according to the state of perfection of the trench system. For special weapons such as machine guns and bomb guns, special shelters have to be made. Extra strong parapets are provided as well as head cover of railroad ties, and every effort is made to keep the exact position of the machine guns secret from the enemy. We soon learnt that he was very anxious to find our machine guns and would shell us liberally in the hope of being able to locate them. Care must be given to the question of drainage. Small ditches should be dug at intervals of a few yards to lead the water to pits in the rear. In Flanders, where we were very near river level, we installed hand and power pumps to keep the water from taking possession of the trenches. Even then, on rainy days we sometimes were in water up to our waists.