42 AMERICAN AGRICULTURE. 



the lime, &c., to benefit the soil. This is a wasteful practice, 

 though the effect is more immediate on the crops; but it is 

 also more transient, and they require to be more frequently 

 renewed. Bones ought always to be saved ; and if not prac- 

 ticable to crush them, they may be thrown upon the land, 

 where they will gradually corrode and impart their fertilizing 

 properties. When partially decomposed and buried just 

 JDeneath the surface, the roots of the luxuriant plants above, 

 will twine around them in all directions to suck out the rich 

 food which ministers so freely to their growth. Crushed 

 bones are advantageously used with nearly an equal amount 

 of ashes, or with one third their weight of gypsum ; or, as 

 with nearly all other saline manures, they may be added to 

 the muck heap. 



PHOSPHATE OF LIME. 



This exists in a fossil state, and is known in some of its 

 forms as apatite, phosphorite, &c. An extensive quarry is 

 found in Estramadura, in Spain, and smaller deposites of it 

 have been discovered in different parts of the United States, 

 under a variety of names. It is probable it may yet be found 

 in such localities and in such quantity as to be useful to the 

 farmer. It has been shown that more than half of the whole 

 weight of bones consists of pure phosphate of lime; its value 

 therefore is apparent. 



SALT OR CHLORIDE OF SODIUM 



Is variously obtained, as fossil or rock salt ; from boiling 

 or evaporation of salt springs ; and from the waters of the 

 ocean. In a pure state it consists of 60 of chlorine and 40 

 of sodium, in every 100 parts. Sodium chemically combined 

 with oxygen forms soda ; and it will be seen by referring 

 to the table, page 32, that salt furnishes two of the important 

 constituents in the ash of every vegetable. Its advantage to 

 vegetation are to be inferred from a knowledge of its compo- 

 sition, which is fully sustained by experience. As a manure, 

 salt was extensively used by the ancients, and has ever since 

 been employed by intelligent agriculturists. On some soils 

 it yields no apparent benefit. Such as are near the sea-coast 

 and occasionally receive deposites from the salt spray, which 

 is often carried far inland by the ocean storms ; or such as 

 contain chlorine and soda in any other forms, are not affected 

 by it. But in other situations, when used at the rate of 3 to 

 16 bushels per acre, the crops of grains, roots or grasses have 



