LIST OF ILLUSTRATIONS 



FIGURES PAGE 



Photograph showing transition from Rock into Subsoil 

 and Soil by Weathering (Hythe Beds, Great Chart, 

 Kent) ...... Frontispiece 



i. Photograph showing Glacial Drift overlying Magnesian 



Limestone ...... 16 



2. Photograph of Soil-sampling Tools . 54 



3. Diagram illustrating Pore Space . . . .67 



4. Diagram illustrating Capillary Rise and Depression of 



Liquids ....... 78 



5. Photograph illustrating Liquid Film round Soil Particles 78 



6. Diagram illustrating Liquid Film round Soil Particles . 80 



7. Water Content of Columns of wetted but thoroughly 



drained Sand and Soil . . . . .83 



8. Diagram showing Rainfall and Percolation at Rotham- 



sted, 1870-1905 ...... 86 



9. Soil Temperatures at 9 a.m., Monthly Means, 1896 . 137 



10. Soil Temperatures at 9 A.M., Daily Readings . . 139 



11. Effect of Nature of Surface upon Soil Temperatures . 145 



12. Temperatures of Drained and Undrained Bog . .150 



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



Northerly Slopes . . . . .152 



14. Temperatures (Max. and Min.) at Various Altitudes . 155 



15. Nitrates in Cultivated and Uncultivated Soil . . 224 



16. Losses of Nitrogen in Drainage from Rothamsted 



Wheat Plots ...... 264 



17. Nature and Distribution of Alkali Salts . . . 286 



