. Bulletin. Agriculture -- New Hampshire. TILE DRAINAGE 29 surveyor to do the job. Where the fall is ample and less accurate work is required, a home-made water level or an ordinary carpenter's level, set on a straight-edge, may be made to answer the purpose. These instruments are illustrated in the cut following. When the total fall, either of the main or laterals, is not quite as great Fig. 3. Different kinds of levels for determining grades. A, sur\-%yor's level; B, carpenter's level; C, home-made water level. The water level is made of half-inch gas pipe, with an upright five feet lon
. Bulletin. Agriculture -- New Hampshire. TILE DRAINAGE 29 surveyor to do the job. Where the fall is ample and less accurate work is required, a home-made water level or an ordinary carpenter's level, set on a straight-edge, may be made to answer the purpose. These instruments are illustrated in the cut following. When the total fall, either of the main or laterals, is not quite as great Fig. 3. Different kinds of levels for determining grades. A, sur\-%yor's level; B, carpenter's level; C, home-made water level. The water level is made of half-inch gas pipe, with an upright five feet long and a cross piece two feet long with elbows on the ends. Corks are put in the elbows and pieces of glass tube inserted in the corks. The top of the upright is then stopped and the cross piece filled with water so that it comes up in the glass tubes. The instrument is used by standing it in the ground and sighting along the water level in the two tubes to the rod. When being carried from one place to another the ends of the tubes must be stopped to keep the water in. is desired, it may be increased by making the drains a little shallower at the upper ends. After the total avail- able fall has been determined, divide it by the number of fifty-foot spaces which the line contains; this, then, will give the fall from one stake to the next. For example,. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original New Hampshire Agricultural Experiment Station. [Hanover, N. H. ] : New Hampshire Agricultural Experiment Station
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