p 



The soil and the pla/iU 



75 



high up in wet hill districts, are covered with grass. In 

 a clay country there is also a great deal of grass land 

 and not much ploughed land ; if you live where there 

 is much clay you can easily discover the reason. Clay 

 becomes very wet and sticky when rain falls, and very 

 hard in dry weather : it is, therefore, difficult to culti- 

 vate. Farmers cannot afford to spend too much money 



Fig. 36. 

 Stephen Hales's Experiment (from Vegetable Staticks, Vol. i. 1727) 



on cultivation, and so they prefer grass, because once 

 it is established it goes on indefinitely and does not 

 want ploughing up and re-sowing. And besides, farmers 

 have learned by experience that grass can tolerate more 

 water and less warmth than most other English crops. 

 There is much more grass land in those parts of England 

 where the rainfall is high and the temperature rather 



