FERTILITY OF SOIL. 115 



have consumed the remaininof two-thirds of all American ter- 

 ritory ! By a calculation that appears in a late report of the 

 Patent Office at Washington, it is estimated that one thousand 

 million of dollars would not more than restore to their origi- 

 nal richness and strength the hundred million of acres of lands 

 in the United States which have been partially exhausted of 

 their fertility. This was the estimate in 1841. 



The older settled portions of our own State can furnish 

 examples of the exhaustive system of farming ; and notwith- 

 standing all the warnings of the wise, and the lessons of his- 

 tory, the occupants of new farms are inclined to pursue the 

 same ruinous policy. 



Scientific farming has, in the crowded populations of the 

 old world, arrested the process of deterioration, and has re- 

 stored the tields to more than their primal fertility. But pre- 

 vention is far better than cure. It is much easier to keep u}) 

 the good condition of a farm than to reclaim worn-out fields. 



The important question now returns, How shall the fertility 

 of virgin soils be retained? 



The first expedient to prevent the loss of fertility, em- 

 ployed b}^ early cultivators, was to let the land have res:; 

 before its strength was too far exhausted. The slow, but 

 constant processes of nature in her marvellous laboratory, 

 supply from the subsoil and the rocky strata around materials 

 that have been removed in the crops. Gradually the coarser 

 rocks are disintegrated, and the finer particles turned to dust 

 yield up their soluble elements. Cold and heat, moisture 

 and dryness, loosen the power of cohesion. The perpetual 

 action of acids and alkalies on the earths, and the new chem- 

 ical combinations ever forming, release plant food from 

 masses formerly inert. The self-repellent property of the 

 molecules of any substance and their attraction for other 

 matter diifuse them through gasses and liquids, and supply 

 the substance that had been removed from any locality. 

 Slowly thus the soil regains its lost elements, and can support 

 constant vegetation. The supply is varied in different locali- 

 ties, according to the nature of the subsoil and the outcrop- 



