Apr. 2-June 25, 1917 
Illustrations 
IX 
Page 
Fig. 8. Diagram showing the distribution of nitrates in plot H before and after 
irrigations. 222 
9. Diagram showing the distribution of nitrates in plot L before and after 
irrigations. 223 
10. Diagram showing the distribution of nitrates in plot M before and after 
irrigations. 224 
11. Diagram showing the distribution of nitrates in plot O before and after 
irrigations. 224 
12. Diagram showing the distribution of nitrates in plot Q before and after 
irrigations. 225 
13. Diagram showing the distribution of nitrates in plot R before and after 
irrigations. *226 
14. Diagram showing the distribution of nitrates in plot S before and after 
irrigations.. 227 
15. Diagram showing the distribution of nitrates in plot U before and after 
irrigations. 228 
16. Diagram showing the nitrate content of the niter spots in furrow-irri¬ 
gated soils. 236 
17. Diagram showing the nitrate content of the niter spots in furrow-irri¬ 
gated soils. 237 
18. Diagram showing the effect of rainfall November 12,1914, to July 15, 
1915, on the distribution of nitrates in soils at Riverside, Cal. 244 
19. Diagram showing effect of rainfall January 7 to January 26, 1916, on 
the distribution of nitrates in soils at Lordsburg, Cal. 246 
Xylaria Rootrot of Apple 
Fig. 1. Longitudinal section of a diseased apple root. 272 
2. Xylaria sp.: a, Hyphae, showing the fusion occasionally noted, b, The 
conidia are hyalin, elongated oval in outline, with a blunt truncate 
pedicel, and measure about 10 by 3 to 3.5^. They are borne singly 
as lateral buds from the sporogenous hypha. 273 
3. Xylaria sp.: Mycelium, showing (a) considerable variation in the fila¬ 
ments; b , d, the young filaments are hyalin, branched, granular, and 
highly refractive* with an average diameter of 2 to 3 n; c,f, the hyphae 
later lose their granular contents, become brown to olivaceous in 
color, and numerous blunt spinulose terminals are developed; e, 
fusion of hyphae. 274 
Comparison of the Hourly Evaporation Rate of Atmometers and Free 
Water Surfaces with the Transpiration Rate of Medicago sativa 
Fig. 1. Graphs showing the hourly transpiration rate of alfalfa, the hourly evap¬ 
oration rate from different surfaces, and the weather conditions during 
a three-day period at Akron, Colo. 280 
2. Ratio of the transpiration rate to the evaporation rate for each of the 
various types of porous-cup atmometers, plotted hour by hour. 282 
3. Graphs showing the transpiration-evaporation ratio: A, The ratio of 
hourly transpiration to the hourly mean evaporation from the atmom¬ 
eters. B, Graph A with ordinates plotted logarithmically. C, 
The ratio of the hourly transpiration to the hourly evaporation from 
the shallow tank, with ordinates plotted logarithmically. D t Graphs 
B (heavy line) and C (light line) superimposed. 287 
4. A comparison of the hourly radiation with the hourly differences in the 
evaporation rate from a brown cylindrical radio-atmometer and a 
white atmometer of the same form. 289 
