T ^ 



1882.] COMMERCIAL FERTILIZERS. i I 



wliat he has always been taught to consider lying — is a "usage of 

 the trade." 



In closing, I must briefly consider the sources of supply of our 

 most expensive fertilizing material — nitrogen. 



Already I have spoken of two nitrogenous materials, Peruvian 

 guano, and ground bone. 



We are also indebted to Peru and Cbili for another fertilizer 

 solely valued for its nitrogen, the cubic niter, or Chili saltpeter. 

 It has long been known that saltpeter or nitrate of potash had a 

 wonderful effect on vegetation, but it has been much too expensive 

 for use in fertilizers, though I am informed by a New York 

 manufacturer that he has lately used it to some extent in special 

 fertilizers. The soda salt however is less valuable in the arts, as 

 the base soda is cheaper than potash, and the fact that soda salt- 

 peter attracts moisture, makes it unsuitable for the manufacture 

 of gunpowder, an industry which consumes large quantities of 

 niter yearly. 



In northern Chili, formerly southern Peru, in the province of 

 Tarapacd there is a vast arid region, a tableland, three thousand 

 feet above sea level, stretching north and south for eighty miles. 

 The trades blow all the year from the Andes, so that the climate is 

 absolutely dry. There is no wood, no water, no vegetation there. 

 Drinking water has to be brought forty-five miles. The only live 

 things to be met with are the mules which carry freight to the 

 port of Iquique and the vultures, who are prompt to call on a mule 

 in distress. Lot's wife in her present state would find the climate 

 by no means unfavorable, and would shine in Tarapaca society. On 

 this plain occur vast deposits of nitrate of soda. It lies in strata 

 five hundred yards wide and seven or eight feet thick in places, 

 interrupted by deposits of common salt. It also occurs in hollows 

 which look like dried up lakes, coating their sides and covering the 

 bottom under a layer of salt. This crude nitrate of soda is 

 purified at the coast by solution, separation from sand, and' crys- 

 tallization, and is then shipped to Europe and the United States. 



With regard to the origin of these deposits we know little. It 

 is conjectured that the nitrogen came in the first case from guano 

 deposits on the shores of an inland salt lake or sea, that through 

 atmospheric agency it was oxidized to nitric acid and then replaced 

 muriatic acid in the salt of the lake and on evaporation was left in 

 its present shape. 



