Food for Plants. 11 



Nitrate of Soda is found in vast quan- 

 Where it is tities in Cliile. Tlie beds of Nitrate, or 



Found. " Caliclie," as it is called in Cliile be- 



fore it is refined, are several thousand 

 feet above the sea, on a desert plain extending for 

 seventy-live 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. 

 The layer of " Caliche " is sometimes eight or ten feet 

 thick, but averages about tliree feet. This " Caliche " 

 contains on an average from 15 to 50 per cent, of pure 

 Nitrate of Soda. 



It is calculated there is ample Nitrate now in sight to 

 last upwards of three hundred years. 



The " Caliche " is refined by boiling in water to dis- 

 solve the Nitrate. This hot water is then run off and 



allowed to cool in tanks, when the Ni- 

 Method of trate forms in crystals like common salt. 



Refilling. The Nitrate is then placed in bags of a 



little over two hundred pounds each and 

 shipped to all parts of the world. 



The process of refining is an expensive one. How 

 these beds of Nitrate were formed has been the subject 

 of much speculation. The generally accepted theory is, 

 that they were formed by the gradual decomposition and 

 natural manurial fermentation of marine animal and 

 vegetable matter, which contains a considerable amount 

 of Nitrogen. 



The same wise Providence that stored up the coal in 

 the mountains of Pennsylvania to furnish fuel for people 

 when their supply of wood had become exhausted, pre- 

 served this vast quantity of Nitrate of Soda in the rain- 

 less region of Chile, to be used to furnish crops with the 

 necessary Nitrate when the natural supply in the soil had 

 become deficient. 



