LOCATIpK AND SOILS. 19 



the heavier being at the bottom and the lighter at the 

 top. An alluvial soil may be divided into four distinct 

 classes : 



1st. Gravelly — So styled from the abundance of 

 small stones or pebbles of granite^, slate, feldspar and 

 limestone. 



2d. Sandy — So styled from its composition of 

 small grains of rock. Coarse sands are generally unprof- 

 itable, while finer sands are more fertile. 



3d. Loamy — So styled as being between the poros- 

 ity of sand, and the tenacity of clay. 



4th. Clayey — So styled from its fineness of texture 

 and retentive power of water. A soil drying and crack- 

 ing under the effects of hot sun. 



A soil, to be fertile, must contain a sufficient quan- 

 tity of the ash ingredients of the plants to be cultivated, 

 and these must be in such soluble condition as to be 

 taken up by the growing plants. Soils once fertile are 

 said to be exhausted when deprived of such food as is 

 required for plant nutrition, but rest and meliorating 

 treatment will, in time, restore such soils to a fertile 

 condition. 



DRAINAaE. 



A soil has good drainage when it is of such compo- 

 sition that the rain filters away without flooding the sur- 

 face, and when, in time of drouth, the evil effects are 

 lessened by the ability of the soil particles to absorb 

 moisture from the air and raise it from the subsoil. 



A soil, to be adapted to gardening purposes, must 

 have fair drainage, either natural or artificial, and it is 

 the wisest course to select land naturally possessing these 

 desirable conditions, as the construction of artificial 

 drains is an expensive operation, often doubling the 

 original cost of the land. 



Good drainage, like tillage, has a vitalizing effect, 

 admitting of the entry of air and the deposition of its 



