Geological and Miscellaneous Notice of Tarapaca. 9 



There being neither water nor fuel in the part of the country 

 where these mines are situated, the ores are transported on the 

 backs of mules to Tirana, for the extraction of the silver which 

 they contain. The process here made use of for that purpose is 

 simple, and, compared with that adopted in many parts of the 

 country, economical. The ore, after having been assorted and 

 broken into coarse fragments, is ground to fine powder by means 

 of a semicircular stone, resting on a flat horizontal bed, which is 

 rocked back and forth on the ore by men stationed on each side. 

 It is then mixed with calcined shells, salt, and mercury, and 

 boiled with water in a copper pan for six or eight hours. When 

 the amalgam formed is sufficiently rich in silver, it is pressed in 

 skins, through the pores of which a part of the quicksilver passes, 

 leaving a ball sufficiently solid to be removed to a stone bench, 

 where it is laid on a grating and covered by an iron cone. This 

 cone is then made secure, by luting at the base, and a fire kin- 

 dled around it to expel the remainder of the quicksilver, which 

 is collected in a dish of water placed beneath. The silver is left 

 light and porous, and in this state is known as plata penia. Pur- 

 chasers before buying generally melt it and run it into bars, or 

 expose it for a long time to a red heat in a furnace, in order to 

 ensure the removal of all the quicksilver. 



In the vicinity of Tarapaca, and in the quebrada called Cauisa, 

 to the southward of Matilla, and in the mountains of Chalacollo 

 and Chalacolito, are small veins of sulphuret of antimony, which 

 afford traces of silver. Near Cocina is a small vein of galena, 

 and in Cauisa there are extensive veins of iron ore. 



In the towns of Tarapaca, Camina, Pica, Matilla and Tirana, 

 the soil is cultivated ; but in the remaining towns of Iquique, Pi- 

 sagua, Mexellones, on the sea-board, and the mining settlements of 

 Guantajay and Santa Rosa, the soil is barren, and the inhabitants 

 are dependent upon distant places for their supplies of provisions 

 and fresh water. The latter is frequently brought from Chili, 

 and commands in Iquique the high price of six cents per gallon. 



In those places where there are means for irrigating the soil, 

 though nearly destitute of organic matter, it is extremely fertile 

 and yields the various fruits common to tropical climes. In the 

 town of Pica grape vines are cultivated, and the fruit affords a 

 peculiar wine of excellent quality. The coast furnishes an abun- 

 dant supply of guano, which is the only manure made use of. 



Vol. xliv, No. 1.— Oct.-Dec. 1842. 2 



