THE BROWN EARTH 27 



getting it on the surface, for they never scrape. 

 I examine the face of the soil, and can see nothing 

 but soil. Evidently the birds have better micro- 

 scopic vision, for they see something every- 

 where, and are doing the gardener a service 

 which he is not too willing to remember when the 

 fruit comes on. That the little eyes of the seed- 

 eating birds are extraordinarily competent in the 

 detection of minute objects disguised in neutral 

 tints is a fact of easy observation. I once lay and 

 watched a wood-lark on a sandy slope near the 

 sea, scantily covered with bent, and noted that it 

 lifted something as quickly and incessantly as if 

 grain had been spread on the place. Examining 

 the surface of the sand I could find nothing bu,t 

 sand, crossed here and there by the wandering 

 roots of the bent. The lark apparently went over 

 the surface with a microscopic lens. But all this 

 careful surface clearance the weeds can stand. 

 They have provided for it, and have plenty of 

 seeds underneath. Those that are buried less 

 than an inch in depth will germinate as the soil 

 warms under the spring sun ; those that are 

 deeper down will wait till some incident in agri- 

 culture brings them up. And if one in ten 

 thousand reaches maturity, and casts seed in its 

 turn, the purpose of the plant will have been served, 

 for the position of the species will have been 

 maintained. 



