STUDIES IN NATURE 



all require moisture, but at the same time will 

 not grow properly if the ground about them 

 becomes soaked with stagnant water. Hence 

 in England, where there is plenty of rain, we 

 generally have to make plans to carry off the 

 excess of water, or to drain the land, as this sort 

 of work is called ; while in hot dry countries the 

 people try to find ways to bring water from the 

 rivers back on to the land, in order to irrigate 

 the crops, as they say. In autumn or winter, 

 when the fields are bare, we may often see men 

 busily digging channels in which pipes are laid 

 and covered over. These are brought to the 

 nearest stream or ditch, and will carry away the 

 heavy rains of the spring and winter, thus leav- 

 ing the surface of the ground in a good condition 

 for the harvest. When the young plants grow up 

 in springtime, they send their roots deeper and 

 deeper into the ground, and follow the water 

 level in the soil, as it gradually sinks lower 

 during the dry summer weather. In this man- 

 ner the roots find their way into fresh soil and 

 get new supplies of food. Certain plants, such 

 as carrots, for instance, have roots that go a 

 long way into the ground ; these keep the 

 plants supplied with moisture in the dry wea- 

 ther, when plants, like lettuce and spinach, 

 which have only surface roots, will dwindle 

 away and die of thirst. 



It is clear that everything which grows on the 

 earth takes a certain amount of substance out 



(98) 



