304 CULTURE OF FARM CROPS. 



drilling system, as described in last paragraph, although 

 well adapted to the different climates and soils met with in 

 the North of England, most "signally fails" in South 

 Britain, the writer proceeds thus : " The frequent ex- 

 posure of the soil by the many ploughings, and more 

 especially the twice drilling of it, dissipates every moisture, 

 and leaves the soil in a condition of parched aridity. The 

 chalky and sandy soils are weak in the cohesion, give off 

 moisture very freely, and radiate caloric very quickly ; and 

 without these two agents no vegetable life can be generated 

 or promoted. On the modified soils of a clayey mixture 

 the frequent workings of the soil convert the tilth into 

 small clods, which resist any mechanical reduction, admit 

 drought between the interstices, by which all moisture is 

 evaporated. If this land be twice drilled, the covering 

 over the dung is wholly composed of dried clods, among 

 which the turnip seed .never vegetates, or so feebly as to 

 fail in future growth. Sowing the seed in rows on the 

 flat grounds by means of machinery with lengthened coul- 

 ters, which make ruts to receive the artificial manures and 

 seed in mixture, has been used with success. It is an im- 

 provement on double ridging, but liable to the objection 

 of depositing the seed among the dry parched dirt that lies 

 on the top of the ground, from which all moisture has been 

 evaporated by the workings of the land and exposure to the 

 atmosphere. The intervals between the rows of turnips 

 being on the level with the roots, do not afford such a 

 convenient room for scuffling as in the hollows of the 

 ridglets ; when the weeds are numerous the destruction is 

 less easily performed. The climate of South Britain is 

 much less humid than of Scotland, the rains are few and 

 distant, and the dews are none. Not a very large degree 

 of heat prevails, but a dry aridity of temperature, that is 

 very parching, and evaporating of moisture. The quantity 

 of moisture is deficient, which being abundantly supplied 

 to dry bodies/ produces the damp and sultry exhalations 

 that are known to constitute one chief cause of fertility. 

 The rains of the summer and spring are planetary in their 



