xviii LIST OF ILLUSTRATIONS 



FIGUKB PAGE 



72. Detailed drawing of the zero section of leveling rods . . 171 



73. Hose-level in use . .174 



74. Nearer view of the hose-level in use . . . . , . 175 



75. Profile of field to be drained 181 



76. Profile of field with long stakes and datum plane shown . 182 



77. Soil underlaid by clay or hard-pan . . . . . 188 



78. Soil on slope underlaid by hard-pan 189 



79. Heavy clay soil 189 



80. Depression in heavy clay on hill slope 190 



81. Depression of soil underlaid by heavy clay on hill slope . 190 



82. Limited flat area of heavy clay on hill top .... 191 



83. Limited area of soil underlaid by heavy clay on hill top . 191 



84. Springy low flat area due to underlying heavy clay or hard- 



pan 192 



86. Springy low flat area due to water rising through clay or 



hard-pan 192 



86. Showing a method for draining single spring . . . 193 



87. Springy area on slope ........ 194 



88. Springy area on slope supplied with water from rock forma- 



tion 194 



89. Small muck area without natural outlet .... 195 



90. Shallow pond resting on muck area 197 



91. Threaded section of brass tubing for studying distribution 



of water in soil columns ....... 226 



92. Apparatus for studying shrinkage of soils .... 235 



93. Apparatus for studying movement of water through tile 



walls, position of water-table in tiled soils, the influence 

 of an inch of rainfall upon the height of ground water- 

 table, and the percentage of pore-space in soil . . 238 



94. Detail of part of Fig. 93 . . . ... .239 



95. Detail of part of Fig. 93 . . . ... . 241 



