July 2-sept. 24, 191 7 Illustrations xiii 



Page 

 Fig. 24. Diagram showing the effect of type of soil on the distribution of capil- 

 lary moiature at different distances from the source of supply, after 

 standing for 139 days 144 



25. Diagram showing the effect of type of soil on the distribution of capil- 



lary moisture at different distances from the source of supply 145 



26. Diagram showing the distribution of moisture in air-dried Greenville 



loam in contact with sand having 7.77 per cent, Greenville loam 

 having 31.09 per cent, and clay having 24.62 per cent of moisture . . 146 



27. Diagram showing the effect of type of air-dried soil on the rate of capil- 



lary movement from various soils used as a source of supply 147 



28. Diagram showing the rate of capillary movement through soil columns 



composed of layers of different types of soils 148 



29. Diagram showing the horizontal distribution of capillary moisture at 



various distances from the source of supply in Greenville loam with 

 different initial percentages of moisture 149 



30. Diagram shomng the horizontal distribution of capillary moisture at 



various distances from the source of supply in soils of different types . 150 



31. Diagram showing the distribution of capillary moisture at various 



distances from the soiu'ce of supply as affected by gravity 151 



Black Rootrot of the Apple 



Fig. I. Root system of a 7-year-old apple tree affected with rootrot 166 



Evaporation from the Surfaces op Water and River-bed Materials 



Fig. I. Map showing the general exposxure and topography of the section of 

 South Denver, Colo., adjacent to the Irrigation Field Laboratory of 

 the Office of Public Roads and Rural Engineering 211 



2. Map showing layout of Irrigation Field Laboratory for season of 1916. . 212 



3. Sketch showing types of evaporation tanks in use at the Irrigation 



Field Laboratory 214 



4. Relative evaporation depths from roimd tanks of varying diameters, 



equal depths, and similar exposure 219 



5. Relation of evaporation and temperatiu-e, all other factors being similar. 229 



6. Relation of water and air temperatures 236 



7. Hydrograph and thermograph sheets at the Denver Irrigation Field 



Station for the week of September 11 to 18, 1916 240 



8. Analysis curves foi: river-bed materials from the Cache la Poudre, 



Colorado, North Platte, Sacramento, San Joaquin, Santa Ana, South 

 Platte, Umatilla, and Yakima Rivers 246 



9. Analysis cTirves for river-bed materials from the Cache la Poudre, 



Columbia, Feather, Sacramento, Salt, Santa Ana, Sevier, and South 



Platte Rivers 247 



10. Analysis curves for materials used in evaporation experiment 248 



1 1 . Relative evaporation losses from different types of river-bed materials . 256 



12. Evaporation losses from stream-bed materials 258 



13. Moisture percentage in top 4 inches of Laboratory soil with water table 



at different depths 259 



Influence op Grading on the Value of Fine Aggregate Used in Port- 

 land Cement Concrete Road Construction 



Fig. I. Graph of hardness tests of artificially graded sand mortar 268 



2. Curve of hardness tests of artificially graded sand mortar 269 



3. Curve of hardness tests of natural concrete sand mortars 269 



