588 



INDEX. 



PACK 



Volatile part of plants xxxii 



Volcanic ash, form soils rapidly ; soils from 20, 54 



Volcanic glass 53 



Volume of soils, changes on wetting and drying 122 



Volume-weight of soils 107 



W. 



Walnut, black, a lime-loving tree 490 to 497 



tolerant of white alkali 479 



Washing-away and gullying of land 217 



Water, capillary 201 



ascent in soil columns, figure 202, 205 



uniform sediments, figure 204, 207 



held at different heights in soil column, table 208 



expansion and contraction in absorbing 208, 209 



maximum and minimum of waterholding power, ter- 

 mination of ; figure 202, 207 



movements in moist soils 210 



carbonated, solvent power 17 



carrying power 14 



controlling factor of soil temperature 301 



density of 190 



effects of flowing 5 



Water-extraction of soils, practical conclusions from 332 



Water, hard 41 



hygroscopic 1 96 



of land-locked lakes 27 



loss of, by irrigation in shallow furrows 240 



physical factors of 188 



regulation of temperature by 191 



relations to heat 189 



requirements of growing plants 192 



plants in arid regions 195 



sidewise penetration of, in soils 24 1 



of soils (chapters on) 188, 215, 234 



solvent action upon soils 327 



solvent power 17, 191 



Water-soluble plant-food 321 



specific heat of 190, 191 



table 227 



vaporization of 191 



Watery soil extracts, from European soils ; tables 327, 329 



American soils, King 329, 330 



Wave action on shores, figure 7 



Weathering, by oxygen, carbonic acid, water 16, 17 



" in humid and arid regions 2, 86 



Weight of soils, per acre-foot 107 



