v.] EARLY AND LATE SOILS 137 



temperatures and preventing severe frosts ; in the 

 British Islands, for example, the earliest potatoes are 

 grown in Jersey, near Penzance, and on other light land 

 along the southern coast of Cornwall, and again a little 

 later near the sea in Ayrshire. Light land round the 

 coasts of Kent and Essex, which borders, and in some 

 cases is almost surrounded by the sea, is also specially 

 valued for the growth of early vegetables. 



The soils naturally retentive of water are late, 

 both because they dry slowly and are rarely fit to work 

 early in the year, and because the high water content 

 keeps their temperature down. Except in long-con- 

 tinued droughts they maintain a supply of water to the 

 plant, their high specific heat keeps them at a com- 

 paratively equable temperature and prevents them from 

 cooling down so soon when the summer heats are 

 past. In consequence, the crop is neither forced early 

 to maturity nor is growth checked so soon in the 

 autumn, the period of development is prolonged until 

 in some cases the season becomes unsuitable for 

 ripening. Many subtle differences may be noticed 

 between the quality of produce grown upon early and 

 late soils ; for example, a comparison made by the 

 author of the same variety of apple grown upon 

 adjoining clay and sandy soils showed that the apples 

 from the clay land were smaller and greener, but 

 contained a greater proportion of sugar and acid, 

 and possessed a higher aroma than the apples grown 

 upon the lighter and earlier soil. Wheat grown on 

 the clays is generally of better quality and " stronger " 

 than that yielded by the lighter soils ; whereas the 

 lighter soils yield the finer barley, in which carbo- 

 hydrates and not nitrogenous materials are characteristic 

 of high quality. On a light soil, becoming both warm 

 and dry early in the season, the plant ceases the sooner 



