10 FOOD FOR PLANTS 



cent, of Nitrogen, equivalent to 18.25 per cent, of 

 ammonia, or 300 pounds of Nitrogen to the ton. 



Nitrate of Soda is found in vast quantities in Chile. 

 The beds of Nitrate, or "Caliche," as it is called in 

 Chile before it is refined, are several thousand feet 



above the sea, on a desert plain extending for seventy- 

 five miles north and south, and about twenty miles 

 wide, in a rainless region. The surface of the desert 

 is covered with earth or rock, called "costra," which 

 varies from three to ten or more feet in thickness. 

 Under this is found the "Caliche," or crude Nitrate. 



