40 MARKET GARDENING. 



go through a course of preparation which, according to 

 the nature of the deposit and the process, develops sul- 

 phate of potash and muriate of potash. 



Nitrogen, as an article of commerce, has been 

 obtained in large quantities from Peru and Chili, in the 

 form of Chili saltpeter, found in the interior of those 

 countries in vast quantities, sometimes many feet in 

 thickness. As much as four million tons have been 

 exported annually, but the Peruvian government has 

 now reserved these deposits for domestic use. Of course, 

 there are other sources of nitrogen, especially in the by- 

 products of manufactures, for example, sulphate of 

 ammonia, from gas works. Animal nitrogen is largely 

 obtained from fish scrap, of which sixty thousand tons 

 are annually produced on the Atlantic coast. Of course, 

 the raw or fresh fish will furnish this same ammonia. 

 The writer has plowed under, on his firm's farms in 

 Lancaster county, Virginia, from seven to nine millions 

 of fish annually; the fish being menhaden, a species 

 slightly smaller than herring. Cracklings from the tal- 

 low works, dried blood and tankage from slaughter 

 houses, are valuable sources of supply for agricultural 

 nitrogen. 



By the introduction of commercial fertilizers farm 

 operations have been freed from the restrictions and 

 limitations imposed by the deficient sources of home- 

 made manures, and the intelligent farmer may vastly 

 extend his operations, while the scientific one turns his 

 farm into a factory, where he endeavors, sometimes, with 

 the aid of climatic influences, and sometimes defeated 

 by such influences, to manufacture his products. 



The world-wide use of commercial fertilizers has 

 served to establish a standard of agricultural value of all 

 the ingredients, and their high price has stimulated the 

 inquiring gardener to a closer scrutiny into the entire 

 subject, not only of plant nutrition, but as respects 



