THE FARMER AT HOME. 337 



chemical and mechanical action of the air, water, and different de- 

 grees of temperature, from the primitive rocks of the earth, incorpor- 

 ated with each other in an endless variety of proportions, and mixed 

 with decayed and other vegetable matter in every stage of decompo- 

 sition. The soil thus formed affords a place for vegetable life, by 

 enabling the seed and plant there to fix itself mechanically to one 

 spot, and by its peculiar properties of affording moisture and the other 

 ingredients necessary for the development of plants in all their stages, 

 to arrive at maturity, and thus furnish a supply of food to man and 

 animals. 



The various ingredients necessary for vegetable life, all exist in 

 the primitive rocks of earth, and by .their destruction these ingredients 

 are rendered available for plants, and as farther, this integration is 

 constantly going on, it must as .a matter of necessity occur, that a 

 greater power daily exists for the support of the vegetable creation. 

 The substances produced by the decomposition of the various strata 

 of the original rock, are potash, soda, phosphoric acid, magnesia, lime, 

 and silex. That such disintegration is constantly going on, is evident 

 from many causes ; and one is, that the lavas in Sicily, which have 

 been thrown out from Mount Etna within a comparatively recent 

 period, are now found covered with a fertile soil, which could only 

 have arisen from this source ; and which is proved to be derived from 

 this cause by the chemical analysis of the rock itself, which yields 

 the substances found under other modifications in the soil itself. 



This fertility is owing to the alkalies which are contained in the 

 lava, and which, by exposure to the combined action of the air and 

 moisture, are reduced to a state capable of being absorbed by plants. 

 A soil which has been subjected to this influence for ages, and from which 

 no crops have beeu removed, will be enabled to support- a luxuriant 

 vegetation for many seasons successively, without any supply of ma- 

 nure, simply because the soil is full of the alkaline matter, phosphates, 

 and other ingredients necessary for the growth of plants ; but when 

 under cultivation, and when the crops are removed from it, it must 

 become gradually exhausted, and unless the alkaline property removed 

 with the crop is restored in the shape of manure to the land, the soil 

 will become eventually quite unable to support a crop and bring it to 

 perfection. To ascertain annually how much of the fertilizing agents 

 of the soil are removed from it in the removal of the crops, and then 

 to restore to it in the form of manure what is equivalent to them, is 

 the province of scientific agriculture. 



SOILING. Cutting green food daily during the summer, and 

 giving it to cattle in yards or stables, is called soiling ; and in some 

 countries is the common method of feeding stock. In our own coun- 

 try, owing probably to the cheapness of land and the dearness of labor, 

 this is as yet but little practiced. The advantages of soiling are, 

 that one acre cultivated for this purpose will afford as much susten- 



