11(3 THE NITRATE OF SODA AND 



Camarones on the north, nor south of the river Loa; however, some say it 

 is found in Bolivia, south of the river Loa, far in the interior, and distant 

 from water. Mr. Smith gives all the positions whence the nitrate is ex- 

 tracted, and also where very large quantities are pretty well known to exist. 

 He likewise notes the spots where the borate of lime is met with. He 

 calculates that the nitrate ground covers fifty square leagues. There have 

 been single square yards of ground that have produced nearly a ton weight 

 of nitrate, the layer being three yards thick. 



If we allow only 100 lbs. weight of nitrate for each square yard, we shall 

 have the enormous quantity of 63,000,000 tons ; so that at the present rate of 

 consumption there is sufficient for 1,393 years. The opinion in the country 

 is that the nitrate is formed from the waters that come from the Cordilleras. 

 There are about forty nitrate works and nine shipping ports, including 

 Iquique. At the Soronal (its lowest position), the nitrate is found at 2,593 

 feet above the sea, and thirteen miles inland ; its most elevated is 3,724 

 feet, and at twenty-three miles. The borate is found as high as about 

 3,600 feet, and as low as 3,211 at the Noria — a town built of salt, and 

 where is found the largest nitrate of soda quarry and refining works. 



Some years since a chalky-looking substance was met with, which was 

 called " Tisa." On examination it was found to be a mineral of borax. 

 Subsequently a box of minerals was sent me by Mr. Smith, in which was 

 enclosed some small specimens of the tisa. This was examined and proved 

 to be a new boracic acid mineral. Mr. Smith came to England, and on his 

 return I begged of him to examine the locality for borate. This he did, 

 and found the district to be very rich in the mineral, as well as various 

 other parts of the Pampa de Tamarugal. It has also been found in the 

 northern part of the desert of Atacama. Preparations were made to work 

 the borate grounds, but the Peruvian Government having been led to 

 believe that it was too valuable an article to be exported, except under 

 similar conditions as the guano — viz., a government monopoly — the working- 

 has been interdicted. Some portion has been extracted, and the greater 

 part smuggled out of the country. Permission has occasionally been given 

 to a favoured few to export small parcels, which bring about £30 per ton 

 in the English market. If allowed to be exported under favourable circum- 

 stances, there would be a good demand, and it would be applied to number- 

 less uses in the arts. I have deposited in the Museum of Practical Geology 

 in London a large nodule of this new boracic acid mineral ; also specimens 

 in the British Museum. Pickeringite and Glauberite occur with the borate. 

 Iodic and chromic salts are found with the native nitrate of soda. 



Formation of Caliche or Nitrate of Soda, and its Manufacture 

 into Befined. — Section of nitrate ground at La Norma, descending — 



I. Costra, or crust, composed of earthy matters, angular pieces of rock- 

 salt, and other saline matters, about two feet thick. 



II. Caliche, granular layers of nitrate of soda, containing salt, other saline 

 and earthy substances, and angular pieces of stone, to five feet thick, often 

 accompanied with much Glauberite (sulphate of soda), some Pickeringite 



