LIST OF ILLUSTRATIONS xvii 



FIGURE PAGE 



46. Profile of a portion of field with stakes in place . . .119 



47. Profile of a portion of field with levels in place . . .121 



48. Diagram to determine fall and depth of ditch . . . 125 



49. Diagram drawn on common note paper to determine fall and 



depth of ditch . 127 



60. Same as Fig. 46 with grade bars and ditch shown . . 132 



51. Ditching tools .135 



52. Tile hook 135 



53. Nailing a grade bar in place 137 



54. Showing line of grade bars in place ready for digging to begin 138 



55. Showing steps in digging and finishing ditch . . . 139 



56. End section of ditch, showing in diagram the bottom of 



ditch formed to receive the tile 141 



57. Showing the way in which bolts may be imbedded in the 



concrete or other outlet protection by which strips of 

 wood may be bolted in place to carry screen to protect 



mouth of outlet from vermin, etc. ..... 144 



58. Showing a galvanized iron trap suspended by hinge to pro- 



tect the mouth of the outlet from entrance of vermin . 146 



59. Five-inch tile with small opening, and hammer used in 



making the opening . . . . . . . 147 



60. Five-inch tile shown in Fig. 59, with the opening enlarged 



to receive 3-inch tile , 148 



61. Shows the connection when the 3-inch tile is fitted in place . 149 



62. A top connection in cross section . . . . . .150 



63. Sections of tile, showing also T and angle .... 160 



64. The way of constructing well for drainage downward into 



underlying gravel 150 



65. Plan for removing drainage water by means of a stone filled 



well and tile 154 



66. Steel shield used to hold back quicksand .... 165 



67. Plan for permitting excess of surface water to reach tile 



drain by filling a section of ditch with crushed stone 



or cobble stone ........ 158 



68. Plan for removing water by way of silt-basin and tile system 159 



69. Hose-level 165 



70. Ends of hose-level showing the way in which the height of 



the column should, be read 166 



71. Leveling rods used with the hose-level . . ',"".* ' 17 



