CONCERNING LAWNS 349 



to penetrate beneath the stone and cement floor 

 after it had been buried so deep in the ground, 

 and when they had, and had enjoyed for over a 

 thousand years at the least, a soil formed of 

 vegetable mould as deep as earthworms require to 

 live and flourish in ? A depth of three or four feet 

 of mould is as much as they require, but they will, 

 Darwin says, occasionally go deeper to five or six 

 feet, and he gives nine feet as the greatest depth 

 at which they have been found. Now at Silchester 

 I saw some taken from a depth of twenty-five feet, 

 and very many at eighteen to twenty feet. This 

 was when the old Roman wells and other deep 

 pits were cleaned out. 



It struck me that these Silchester observations 

 made a valuable contribution to a history of the 

 earthworm's life habits. For it should be borne 

 in mind that the soil covering the buried city is a 

 rich mould, which has been under cultivation for 

 the last nine or ten centuries, and is the kind of 

 soil in which the earthworm finds his best con- 

 ditions and attains his greatest size and vigour. 

 Consider next that the soil in the deep pits and 

 everywhere beneath the Roman pavements is a 

 cold, heavy, hardly-pressed earth undisturbed for 

 many centuries, unpierced by root of plant or ray 

 of sun, and probably to a great extent devoid of 

 the microbic life which makes the upper soil alive. 

 When you turn over this long-buried soil with the 

 spade it has a heavy damp smell, but not the 

 familiar earth-smell of Clodothrix odorifera. Yet 



