Scientific Intelligence — Mineralogy^ 4S1 



M INERALOGY. 



8. Nitrate of Soda Quarries in Peru ; — and Anhydrous Sulphate 



of Soda In the moming after breakfast, says a correspondent 



of the Literary Gazette, in No. 1279, we set out to examine the 

 nitre-quarries and clarifying works. The nitre is found upon a 

 small portion of the plain, extending along whore the latter and high 

 grounds between it and the sea blend together for a distance, in a 

 north and south bearing, of about 160 miles ; but nitre-works are 

 only as yet established upon a small portion of this line. It is com- 

 bined with the soil to the depth of three feet, the two forming so hard 

 a mass as to require boring and blasting, after which it is pounded, 

 dissolved, clarified, and crystallized, and packed off on donkeys to 

 Iipique, where it sells for three and a half dollars per 100 lb., duty 

 included. The residuum, after the extraction of the nitre, both from 

 taste and appearance, could not be mistaken ; while the further in- 

 formation that it was a deadly poison, and the clothes once wet with 

 it never dried, still more clearly pointed out the muriate of lime. This 

 nitre, as it is called, is not the proper nitre, which is the nitrate of 

 potassa, but simply the nitrate of soda. The proper nitre is an efflo- 

 rescent salt, which dries up into a light powder when exposed even to 

 a moist atmosphere, while the nitrate of soda of Tarapaca is a deli- 

 quescent salt that runs to solution under similar circumstances ; but 

 the climate of Western Peru being totally destitute of moisture, hence 

 this nitrate is found to answer well there in the manufacture of gun- 

 powder as a substitute for the real nitre, and in which way it has 

 long been applied. In Europe it is used in manufacturing rockets 

 and other fireworks for saint-day displays in Catholic countries, 

 and as manure for particular soils. Western Peru furnishing al- 

 most nothing but the precious metals to make a return to England in 

 payment of manufactures, hence this nitre was immediately hailed as a 

 great boon to the return ships by furnishing them a profitable ballast. 

 Many other mineral substances exist on this coast, from which an 

 equally good trade might be derived; among which I may mention the 

 anhydrous Glauber salt, or Glauber salt, having no water of crystalli- 

 zation, of which a nephew of the celebrated Bolivar at Cobija, who gave' 

 me a specimen, told me there was an inexhaustible supply in the 

 valley of Atacama and other contiguous places. The sulphate of 

 soda, or Glauber salt, is now extensively used in England in the ma- 

 nufacture of British soda ; hence it may be advisable for mercantile 

 men to turn their attention to these Peruvian mines, where it is <rot 

 for the digging ; and the water of crystallization amounting to about 



