M ANUSES. 151 



That this removal of one of the most valuable con- 

 stituents of the soil has been the cause of more ex- 

 haustion of farms, and more emigration, in search 

 of fertile districts, than any other single effect of 

 injudicious farming, is a fact which multiplied in- 

 stances most clearly prove. 



It is stated that the Geuesee and Mohawk valleys, 

 which once produced an average of thirty-jive or, 

 forty "bushels of wheat per acre, have since been 

 reduced, in their average production, less than twen- 

 ty bushels. Hundreds of similar cases might be 

 stated ; and in a large majority of these, could the 

 cause of the impoverishment be ascertained, it would 

 be found to be the removal of the phosphoric acid 

 from the soil. 



The evident tendency of cultivation being to con- 

 tinue this ruinous system, and to prey upon the vital 

 strength of the country, it is necessary to take such 

 measures as will arrest the outflow of this valuable 

 material. This can never be fully accomplished 

 until the laws which regulate the nutrition of plants 

 are generally understood and appreciated by the 

 people at large. The enormous waste of the most 

 valuable manures, taking place not only in every 

 city, but about every residence in the land, can only 

 be arrested when the importance of restoring to the 

 soil a full equivalent for what is taken from it is 

 universally realized. China and Japan, the most 

 densely peopled countries in the world, have been 

 cultivated for thousands of years with no diminution 

 of their fertility. Japan is about as large and about 



