603 



Tile drains, Influence soil ventilation, 

 211 ; fluctuations In rate of flow from, 

 I'TU : leveling for, 3i_; lor road 

 drainage, 448. 



Tillage, checks concentration ^f alkal!, 

 influence of on development of 

 nitrates, 105 : to conserve soil mois- 

 ture, 182 ; effectiveness of increased 

 by frequency, 1ST ; too great frequency 

 undesirable, 189 ; disadvantages of 

 late. 189 : should be most frequent in 

 spring, 19 ; following rains, 190, 

 should varv with season, 11H : best 

 time for, 192; subsoil ing, 195: in- 

 fluence of on soil ventilation, 209 ; in- 

 fluence of on soil temperature, 219, 

 222 ; objects of, 223. tools for earliest, 

 225, 234 ; for later cultivation. 1126 ; 

 to cover weed in row, 228 ; garden 

 cultivators for, 230; to modify soil 

 texture. 231 ; plow as a tool for, 238. 



Tilth, importance of good, 233 ; how de- 

 veloped, 233 ; modified by plowing, 239. 



Timber, strength of, 330 to 334 ; safe 

 center loads, 338 : selection of, 338 ; 

 construction of from 2-inch lumber. 

 339. 



Tires, effect of width on draft, 436 ; con- 

 trol of width, 481. 



Topography, influence of on soil tenriera- 

 ture, 218. 



Tornadoes, 586 ; relation to storms, 

 586 : oriein, 589. 



Towers, night for windmills, 534. 



Traces, influence of slope on draft, -140, 

 441, 492. 496. 



Traction, see draft. 



Trautwine, 332, 381. 



Tread power, 499. 



Tresaguet, type of road. 462. 



Triceps muscle, measuring strength of, 

 489. 



Traube, precipitation membranes, 44. 



Tubes, capillary rise of water in, 37, 

 cause of variation of bight of water in, 

 161 ; flow of water through. 300. 



Turnip, temperature for germination of, 

 213. 



U 



Dnder drainage, influence of on soil ven 

 tilation, 210; practice of. 311; tools 

 for, 312 ; determining levels for, 312 : 

 for roads. 445 to 448. 



Units, of energy, 27 ; of heat 28 ; of 

 work, 18, 27. 



Valentin, respiration, 353. 



Valve, slide, of steam engine, 518; of 

 gasoline, engine, 528. 



Vegetation. Influence of on soil ventila- 

 tion. 211 



Vtutilation of soil, lessened by rolling 

 192 ; needs for, 204 ; Imperfect In 

 water logged soil, 205 ; may be exces- 

 sive, 200 ; processes of, 207 ; due to 

 changes in temperature, 207 ; influ- 

 enced by changes in barometric 

 pressure, 208; influenced by wind suc- 

 tion, 208; influenced by percolation, 

 209 ; modified by tillage, 209 ; by 

 underdraining, 210, 287, 200; influ- 

 enced by vegetation, 211. 



Ventilation of farm buildings, 350 ; ma- 

 terials to be removed by, 350 to 353 ; 

 lack of predisposes to disease, 352 ; 

 amount of air required lor. :;r>3 t-> 

 355 ; forces producing, 358 ; types of, 

 355 to 3G5 ; of silos, 417 ; of box 

 stalls, 387. 



Ventilating flues, capacity of, 355 ; es- 

 sential features of, 358 ; location of, 

 359 ; for basement stables, 355, 356, 

 364 ; openings into, 360 ; for fresh 

 air, 362 ; construction of, 363. 



Vierordt, respiration, 353. 



Viscosity, modified by dissolved salts, 

 106 ; table of coefficients of, 264. 



Voelcker, nitrogen in soil, 82. 



W 



Wagner, illustration of symbiosis, 87, ef- 

 fect of Chile saltpeter, 88. 



Wagon, draft of, 434 to 443, 490. 



Walls, solid masonry, 346 ; hollow ma- 

 sonry, 347 ; brick veneered, 347 ; wood, 

 348; relation of to floor space, 366; 

 rigidity of for silos, 394. 



Waring, denitrification, 90. 



arinfrton, distribution of nitrogen In 

 soil, 84 ; amount of nitric acid in soil, 

 84 ; formation of nitric aciJ in the at- 

 mosphere, 86 ; denitrification 90. 



Water, specific heat of, 29 ; influence of 

 on climate, 29 ; use in cooling mi.K. 34 ; 

 amount stored in rock, 51, 257 ; work 

 of in soil formation, 54, 78 ; flow of 

 through sand, 123 ; conditions of In 

 soil, 129, 130; amount of required by 

 crops, 139, 140 ; least amount re- 

 quired by different yields, 141 ; trans- 

 piration of, 145; absorption of by 

 roots, 147: capillary rise of in tubes, 

 161, in soils, 163 ; amount and move- 

 ment of influenced by subsoil ing, 197 ; 

 innuence of movements of on soil ven- 

 tilation, 209; amount of stored In soil 

 and rock, 255; seepage of 258. 251) : 

 laws of flow through porous media, 

 262, 264 ; measurements of flow of 

 through sands and sandstone. 204, 266, 

 268; fluctuations in rat<> of tlmv of 

 from springs, 270, 271 ; rise and fall 

 of in wells, 272; temperature of In 

 wells, 284 ; how It enters tile drains, 

 292 : movement of toward tile drains, 



