. Agricultural engineering; a text book for students of secondary schools of agriculture, colleges offering a general course in the subject and the general reader. Agricultural engineering. DRAINAGE 89 treads which provide a large area of supporting surface. These machines can be used to the best advantage on long lines of tile and where the soil is reasonably dry and free from boulders. In no case should a machine be used which does not permit of an inspection of the grade and of the tile as it is laid. The Guess System of Laying Tile. At the present time there is very little tile placed in t
. Agricultural engineering; a text book for students of secondary schools of agriculture, colleges offering a general course in the subject and the general reader. Agricultural engineering. DRAINAGE 89 treads which provide a large area of supporting surface. These machines can be used to the best advantage on long lines of tile and where the soil is reasonably dry and free from boulders. In no case should a machine be used which does not permit of an inspection of the grade and of the tile as it is laid. The Guess System of Laying Tile. At the present time there is very little tile placed in the ground on grade lines made simply by guess. The majority of such systems are failures, and mistakes have been so evident where this method was practiced that it is uncommon now to see a system installed without a survey. The Water-Level Method. But little better than the guess method of installing drainage systems, is the water- level method, which is used to some extent today and is responsible for a large number of failures. This method of laying tile is used where there is some water in the ditch. Where the fall is slight, water can not be depended upon to give a proper grade. The ditch is sure to be dug below the grade at certain places, giving a back fall. After the ditch has been dug too deep, there is little chance of correcting the mistake by filling in. The water-level method is so inaccu- rate that, even where the fall is great and there is little danger of creating back fall, the grade line will be so irregular that the efficiency of the tile will be much reduced. Method of Grad- ing Ditches. Two general methods of Fig' 5G" The ^^ch^ °f grading ttli. 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 Davidson, Jay Brownlee, 1880-1957. St. Paul, Minn. , Webb Pub. Co.
Size: 1910px × 1308px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectagricul, bookyear1919
