quarter of an inch open, to give free entrance to the water. The stone and tile drain, _H, I_, is simply dug out to the surface of the rock, if this is not more than two feet below the grade of the upper ends of the laterals with which it connects, and then filled up with loose stones to the line of grade. If the stones are small, so as to form a good bottom for the tiles, they may be laid directly upon it; if not, a bottom for them may be made of narrow strips of cheap boards. Before filling, the tiles and stone work should be covered with shavings, and the filling above these should consist of a strong clay, which will remain in place after the shavings rot away. *Amending the Map.*—When the tiles are laid, and before they are covered, all deviations of the lines, as in passing around large stones and other obstructions, which may have prevented the exact execution of the original plan, and the location and kind of each underground silt-basin should also be carefully noted, so that they may be transferred to the map, for future reference, in the event of repairs becoming necessary. In a short time after the work is finished, the surface of the field will show no trace of the lines of drain, and it should be possible, in case of need, to find any point of the drains with precision, so that no labor will be lost in digging for it. It is much cheaper to measure over the surface than to dig four feet trenches through the ground. CHAPTER V. - HOW TO TAKE CARE OF DRAINS AND DRAINED LAND. So far as tile drains are concerned, if they are once well laid, and if the silt-basins have been emptied of silt until the water has ceased to deposit it, they need no care nor attention, beyond an occasional cleaning of the outlet brook. Now and then, from the proximity of willows, or thrifty, young, water-loving trees, a drain will be obstructed by roots; or, during the first few years after the work is finished, some weak point,—a badly laid tile, a loosely fitted connection between the lateral and a main, or an accumulation of silt coming from an undetected and persistent vein of quicksand,—will be developed, and repairs will have to be made. Except for the slight danger from roots, which must always be guarded against to the extent of allowing no young trees of the dangerous class to grow near a drain through which a _constant_ stream of water flows, it may be fairly assumed that drains which have been kept in order for four or five years have passed the danger of interruption from any cause, and they may be considered entirely safe.