X List of Illustrations 



FIOUBB PAOB 



33. Wheat growing in moist and in dry soils . . . 71 



34 a and b. Plants found on a dry soil had narrow leaves, 



those on a moist soil had wider leaves. Fhot 8. T. 



Parkinson 72, 73 



35. Plants give out water through their leaves ... 74 



36. Stephen Hales's experiment in 1727 .... 75 



37. Hill slope near Harpenden showing woodland at top and 



arable land lower down. Phot. Lionel Armstrong . 77 



38. View further along the valley; woodland and arable 



above, rough grassland near the river. Phot. Lionel 

 Armstrong 79 



39. Rough grass pasture near the river. Higher up is arable 



land. Phot. Lionel Armstrong . . 81 



40. After harvest the farmer breaks up his land with a 



plough and then leaves it alone until seed time. 



Phot. Lionel Armstrong ...... 83 



41. Rolling in mangold seed on the farm. Phot H. B. 



Hutchinson 85 



42. Soil sampler 88 



43. Cidtivation and mulching reduce the loss of water from 



soils 90 



44 a and b. Maize cannot compete successfully with weeds 94, 95 



45. A plot of wheat left untouched since 1882 at Rotham- 



sted has now become a dense thicket. Phot. Lionel 



Armstrong 97 



46. A badly drained wheat field 99 



47. Highly cultivated sandy soil in Kent .... 103 



48. A Surrey heath 105 



49. Woodland and heather on high sandy land, Wimbledon 



Common. Phot. R. H. Carter . . . . . 107 



50. Poor sandy soil in Surrey, partly cultivated but mainly 



wood and waste ....... 109 



51. Open chalk cultivated country, Thanet. . . . 113 



52. Clifis at the seaside, Manorbier. Phot. Geological 



Survey 117 



53. Cliffs in inland district, Arthur's Seat, Edinburgh. 



Phot. Geological Survey 119 



54. Model of a stream 120 



55. The bend of a river 121 



56. The winding river— the Stour at Wye. Phot. R. H. 



Carter 123 



57. Sketch map showing why Godmersham and Wye arose 



where they did on the Stour 126 



58. Ford at Coldharbour near Harpenden. Phot. Lionel 



Armstrong 127 



The photographs of the pot experiments are by Mr Lionel 

 Armstrong. 



