CLASSIFICATION OF FERTILIZERS. 99 



and other elements which come down dissolved in the 

 rain. These, acting on each other, and quickened in their 

 action by the air, by the sun s light and heat, and by the 

 electric and vital influences of the plants, continually 

 prepare for the use of plants, the food which they need, 

 in the form best suited to their nourishment. 



830. To the question, Which are more important, the 

 atmospheric elements thus furnished, or the earthy or 

 mineral ? we answer, Both are equally important. Both 

 are indispensable. They are necessary to each other. A 

 soil rich in organic substances, attracts and retains the 

 atmospheric elements in abundance proportioned to its 

 richness. Such a soil puts the earthy elements into a 

 condition suited to the wants of vegetation ; and, the more 

 readily and abundantly, in proportion to the fulness of the 

 supply of these earthy elements. 



331. Fertilizers may accordingly be divided into two 

 great classes, viz. : Inorganic or Mineral Fertilizers, and 

 Organic, or Vegetable and Animal Manures, 



OF INORGANIC OR MINERAL FERTILIZERS. 



332. In their general character, inorganic fertilizers 

 are both manures and amendments. They furnish nour 

 ishment to plants, at the same time that they exert a 

 mechanical action upon the texture of the soil, upon its 

 lightness, stiffness, compactness, &c. 



333. The principal mineral fertilizers are lime, marl, 

 plaster, wood ashes, ley, soot, sulphates and other salts 

 of ammonia, phosphates and super-phosphates of lime, 

 common salt, carbonates, nitrates, silicates of potash and 

 soda, sulphates of soda, of lime, and of magnesia, &c. 

 But all of these are not in common use. 



