34 LIVING LIGHTS. 



a system of irrigation and ventilation for the upper crust. 

 In other words, rain, instead of running off, enters the holes, 

 and so penetrates the earth, thus being held for a longer 

 time. Air also finds its way below the surface ; so that 

 the homes of the little creatures constitute storehouses for 

 moisture. 



But this is a very small part of the work accomplished. 

 The worms are in league with the farmer ; are, in fact, his 

 unappreciated assistants, upon whose endeavors depends 

 much of the success of his crops. They are continually 

 swallowing the earth, and depositing it at the surface, and 

 working it over and over. If I should ask my young readers 

 to estimate the quantity of earth brought to the surface in 

 a single acre in a year, I fear they would not place the 

 amount as high as Mr. Darwin, who states that the vegetable 

 mould thus transported in some places amounts to ten tons 

 an acre. " Think of it ! If your ten-acre farm is in one of 

 these favored localities, these silent workers, say to the 

 number of a million, have ploughed up about one hundred 

 tons of earth for you, giving you a fine top dressing. 



The worms not only carry all this material to the surface, 

 but they drag vast quantities of leaves and other matter 

 down, that serve to enrich the soil and render it capable of 

 producing larger crops. They cover up seeds and other 

 objects to a remarkable extent ; and a flat rock set upon the 

 ■ground will soon become buried, through their means. Some 

 of the most interesting parts of Roman villas found in Eng- 

 land have been, according to Darwin, preserved in this way ; 

 the worms undermining them, and gradually heaping soil 

 over the walks and slabs, until finally, aided by other causes, 

 they disappeared beneath the ground. 



