102 AMERICAN MANURES. 



Bonedust 552 Ibs. 



Epsom Salts 326 " 



Dry Pearl Ash 465 " 



Quicklime 70 " 



Common Salt 116 " 



Total 1529 Ibs. 



The constant removal of such large quantities 

 of the inorganic food of plants must, in time, ex- 

 haust a soil and render it barren, unless restored 

 by a judicious system of manuring. The soluble 

 salts, such as potash and soda, are also liable to 

 leach through to the subsoil, and also to be 

 washed away by rains. In general, however, all 

 fertile soils contain a good store of the inorganic 

 food of plants, so that the deterioration is often 

 a slow process. In rare instances, a century 

 may elapse before the change prove such as to 

 make a sensible diminution in the rental value. 

 Such slow changes are seldom recorded. Hence 

 the practical man is occasionally led to despise 

 the clearest theoretical principles, because he 

 has not happened to see them verified in his own 

 limited experience; as well as to neglect the 

 suggestions and wise precautions which these 

 principles lay before him. Illustrations of this 

 sure, though slow decay, may be met with in 

 the agricultural history of almost every country ; 

 but in none more strikingly than in the old slave 

 States, Maryland, Virginia, North and South 



