LIST OF ILLUSTRATIONS 



FIGURES PAGE 



Photograph showing transition from Rock into Subsoil 

 and Soil by Weathering (Hythe Beds, Great Chart, 

 Kent) • • . . . • • Frontispiece 



1. Photograph of Soil-sampling Tools • • .49 



2. Diagram illustrating Pore Space . • . 62 



3. Diagram illustrating Capillary Rise and Depression of 



Liquids ....... 72 



4. Photograph illustrating Liquid Film round Soil Particles 73 



5. Diagram illustrating Liquid Film round Soil Particles . 75 



6. Water Content of Columns of wetted but thoroughly 



drained Sand and Soil ..... 76 



7. Diagram showing Rainfall and Percolation at Rotham- 



sted, 1870-1905 ...... 78 



8. Soil Temperatures at 9 a.m., Monthly Means • . 122 



9. Soil Temperatures at 9 A.M., Daily Readings . . 123 



10. Effect of Nature of Surface upon Soil Temperatures . 128 



11. Temperatures of Drained and Undrained Bog . . 132 



12. Distribution of the Sun's Rays on Southerly and 



Northerly Slopes . . . . 133 



13. Temperatures (Max. and Min.) at Various Altitudes . 135 



14. Nitrates in Cultivated and Uncultivated Soil . . 195 



15. Losses of Nitrogen in Drainage fiom Rothamsted 



Wheat Plots ...... 226 



16. Nature and Distribution of Alkali Salts . • • 246 



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