3io 



INDEX 



Shrinkage of clay on drying, 34, 

 284. 



Silica, 17. 



Silt, 53. 



Soil, alkali, 245, 272 ; analyses of 

 typical, Appendix I.; description 

 of, 7, 29 ; drift, 8 ; gases, 13 ; 

 inoculation, 183 ; mulch, 107; of 

 transport, 8 ; relation to subsoil, 

 7, 26, 194 ; sedentary, 7; surveys, 

 289 ; temperatures, 122 ; typical, 

 55, 149, 271; worn-out, 28, 257. 



Soot, effect on temperature of soil, 

 128 ; effect on texture of soil, 253. 



Specific heat of soils, 128, 275. 



Spring on impermeability of clay, 



71. 

 Spring cultivation, gain of water by } 



97 ; frosts, 135. 

 Stahl on mycorhiza, 205. 

 Sterility of soils, 241. 

 Stoklasa on alinit, 173. 

 Stones, reputed growth on arable 



land, 12 ; retention of moisture 



by, 105 ; warming effect of, 131. 

 Subsoil, description of, 7, 26, 194 ; 



as regulator of water supply, 100 ; 



packing, 107. 

 Surface of soil particles, area of, 65 ; 



rise of salts to the, 245. 

 Surface tension, 71; cohesion due 



to, 82 ; variations in, 81 ; water 



lifted by, 97, 106. 

 Surveys, soil, 289. 

 Symbiosis, 169. 



Talc, 22. 



Temperature, effect of colour on, 



127; effect of exposure on, 133 ; 



required for growth, 120, 123 ; 



weathering due to alternations 



of, 9. 

 Texture of soil, 32, 60, 251. 

 Thanet sand, soils on, 236. 



Tillage and soil water, 89. 

 Tilth, 97, 253. 

 Transpiration water, 89. 

 Typical soils, chemical analysis of, 

 149 ; mechanical analysis of, 55. 



UREA, conversion into ammonia, 

 172. 



Valley frosts, 134. 



Velocity of currents carrying sand 

 grains, 33. 



Ville on fixation of nitrogen, 179. 



Vineyards, stones on surface of, 105. 



Virgin soils, nitrogen in, 189. 



Voelcker on absorption of manures 

 by soil, 212 ; on analysis of drain- 

 age waters, 222 ; on fixation of 

 nitrogen, 179; on "finger-and- 

 toe " in turnips, 209. 



Wagner on denitrification, 199. 



Warington on determinations of 

 nitrates in soils, 147; on denitri- 

 fication, 198 ; on nitrification, 191 ; 

 on wetness of land in February, 

 88. 



Warp soils, 255 ; growth of potatoes 

 on, 2. 



Water capacity of soil, 67. 



Water table, 77. 



Way on absorption of salts by soil, 

 212. 



Weathering, 7, 8 ; due to alterna- 

 tions of temperature, 9 ; due to 

 frost, 11; due to water and car- 

 bonic acid, 13 ; due to roots, 14 ; 

 of granite, 19 ; of basalt, 21. 



Weight of a cubic foot of soil, 64. 



Wheat as an exhausting crop, 237. 



Wilfarth on fixation of nitrogen, 1 80. 



Wilting of plants in soils containing 

 water, 84. 



