ARBORICULTURE. 365 



The birch and the beech, are found to succeed better on a soil 

 of the above description than any other kind of tree. For the 

 latter, however, it is necessary that the subsoil should be a deep 

 sand. The larch and spruce, under the like circumstances as to 

 subsoil, will also attain to a good perfection on heath soil ; but 

 where the subsoil is rocky, or impervious to a free circulation 

 of moisture by indurated sand, which is sometimes the case, 

 these last-mentioned trees never succeed. 



2d. 400 parts of poor sandy soil, incumbent on shale, or very 

 coarse gravel. 



Fine sand, principally siliceous, . . . 360 

 Impalpable earthy matter, 40 consisting of carbonate 



of lime, ....... 



Decomposing vegetable matter, destructible by fire, 4 



Silex, or pure earth of flints, .... 22 



Alumina, or pure matter of clay, ... 7 



Oxide of iron, ...... 5 



Soluble saline matters, chiefly muriate of-soda, . 2 



400 

 The pine, larch, spruce, birch and sycamore are the most 

 proper for this kind of soil. 



3d. Sandy loam, incumbent on siliceous sand, containing a 

 large proportion of oxide of iron. 400 parts. 



Fine sand, partly calcareous, and partly siliceous, 200 



Coarse sand, .... 



Carbonate of lime, ...... 6 



Decomposing vegetable matter, . . . 15 



Silex, or the earth of flints, .... 56 



Alumina, ....... 12 



Oxide of iron, ....;. 5 



Soluble vegetable matter, containing sulphate of potash, 



vegetable extract, and common salt, . . 4 



Loss, 24 



400 



