AGRICULTURE. 



373 



He who possesses on his estate the three earths, 

 clay, sand, and lime of a good quality, with facili- 

 ties for drainage or irrigation, has all the materials 

 for permanent improvement ; the grand desiderata 

 \n agriculture being to render wet lands dry, to sup- 

 ply dry lands with sufficient moisture, to make ad- 

 hesive soils loose, and loose soils sufficiently ad- 

 hesive. The intermixture of soils, where one kind 

 of earth is either redundant or deficient, is practised 

 in some countries with great advantage. Part of 

 Lancashire is situated on the red sandstone. This 

 rock, being principally composed of silicious earth 

 and the oxide of iron, forms of itself very unpro- 

 ductive land ; but, fortunately, in many situations it 

 contains detached beds of calcareous marl near the 

 surface. By an intermixture of this marl with the 

 soil, it is converted into fertile land, and the neces- 

 sity for manure is superseded. The effect of a 

 good marl applied liberally to this land, lasts for 

 more than 20 years. In some lands a mixture of 

 light marl, which contains scarcely a trace of cal- 

 careous earths, is found of great service. The 

 good effect of this appears to depend on its giving 

 to the sandy soil a sufficient degree of tenacity. 

 The steril and gravelly soils in Wiltshire have 

 been recently rendered productive by mixing them 

 with chalk ; the most liberal application of manure 

 having been found ineffective or injurious. In stiff 

 clay soils, where lime is at a great distance, the 

 land might frequently be improved by an intermix- 

 ture with silicious sand. A proper knowledge of 

 the quality of the subsoil, and the position of the 

 sub-strata, is necessary to ascertain the capability 

 of improvement which land may possess. It may 

 frequently happen, that a valuable stratum of marl 

 or stone, which lies at a great depth in one situa- 

 tion, may rise near the surface in an adjoining part 

 of the estate, and might be procured with little ex- 

 pense When earths are properly intermixed, in- 



