Vlll LIST OF ILLUSTRATIONS 







Figures Page 



82 Blank form used in recording measurements of levels 



taken down grade 190 



83 Profile showing surface and grade line of ditch 192 



84 System of mapping drains and sizes of tiles in a low 



place 195 



85 Cross section of field showing elevation of soil above the 



datum plane 197 



86 Cross section of field showing the depth of the ditch as 



finally calculated 197 



87 How water seeks the drains 198 



88 Showing disposition of earth handled with road machine 



and spade 199 



89 Different dimensions of ditch for receiving drain tiles of 



different sizes 200 



90 Tile or ditching spade 201 



91 Small tile spade 201 



92 Tile hoe for grading bottom of tile ditch 20Z 



92a Tile hoe, adjustable to push or pull 202 



93 Method of spading out successive courses in opening a 



ditch for tiles 203 



94 Showing the successive operations necessary in construct- 



ing tile drain 204 



95 Triangular tile drain grader 205 



96 Grading frame used in leveling bottom of tile ditch .... 206 



97 Mason's level 207 



98 Detail of construction of grading frame 207 



99 Students preparing ditch for laying tile 208 



100 Students constructing tile drain 209 



101 Manner of accurately determining the proper depth to 



grade bottom of the ditch 210 



102 Effects of faulty grading of bottom of ditch 210 



103 Laying tile drains 211 



104 Tile hook 212 



105 Masses of maple roots taken from drain tiles 213 



106 Filling tile ditch with drag or slush scraper 214 



107 Filling tile ditch with especially constructed scraper. ... 214 



108 Filling tile ditch with a reversible road machine 215 



109 Tile-ditching machine opening four-foot ditch 216 



110 Mole ditcher 217 



111 Outlet to tile drain or to earthen pipe culvert 218 



112 Outlet to drain protected by masonry 218 



113 Improperly protected outlet for drain 219 



114 General plan of silt well 220 



1 1 5 Drag or slush scraper 220 



1 1 5a Fresno scraper 221 



116 Wheel scraper lowered for filling 221 



117 Reversible road machine making lateral ditches 222 



118 Form of ditch beside fence line 222 



119 Elevating grader opening large ditch 223 



