Establishing a Grade.--If the grades are light, they should be established by use of a telescope level. Most of the cheap levels are a delusion. A stake driven flush with the surface of the ground at the outlet becomes the starting point, and by its side should be driven a witness stake. Every 100 feet along the line of the proposed drain and laterals similar stakes should be driven. Their levels should then be taken, and when the fall from the head of the system to the outlet is known, the required cut at each 100-feet station is easily determined. It may be necessary to reduce or increase the grade at some point to get proper depth in a depression or to save cutting when passing through a ridge. Cutting the Trenches.--There are ditching-machines that do efficient work. The best are costly. Most of the work on farms will continue to be done with ditching-spades. The ground should be moved when wet, so that labor can be saved. A line should be used to secure a straight side to the trench. The grade should be obtained by means of a system of strings. If two light poles be pushed into the ground at each 100-feet station, one on either side of the proposed trench, and a string be drawn across at a point 5-1/2 feet above the bottom of the proposed trench, these strings will be in line on a grade 5-1/2 feet above the grade the drain will have. As the cut at the station is known, the height of the string above the top of the stake is easily determined. These strings will reveal any inaccuracy in the survey. The workman can test every part of the bottom of the trench by use of a rod 5-1/2 feet high, the top end being exactly in line with the strings when the lower end is placed on the correct grade of the trench. This device is better than running water where grades are slight. A drain scoop should be used in bottom of the trench to make a resting place for the tile that will prevent any displacement by the soil when the trench is filled. Depth of Trenches.--Underdrains may be placed too deep in close soils for best results. In an early day it was advised that the drains be put down 4 feet deep. We now know that a tight clay soil may give best results from a drain only 28 inches deep, or even a little less. In a looser soil 3 feet is a better depth, and in porous swamp lands the drain may well go 4 feet deep, thus permitting increase in distance between drains. Connections.--The laterals should enter the branches and mains near the top, so that the water will be drawn out rapidly. The tile should be laid with close joints at the top, so that the water may enter more freely from the sides than the top. No covering other than moist soil is needed unless there is very fine sand, when paper over the joints will serve a good purpose. After some moist soil from the sides of the trench has been tramped upon the tile, the trench may be filled by use of a breaking-plow or winged scraper.