DEPOSITS OF NITRATES 293 



abundant around caves which serve as the refuge of birds and bats, 

 as described by Humboldt. The nitrogenous matters, which come 

 from the decay of the remains of these animals, form true de- 

 posits of guano which is gradually spread around, and which, in 

 contact with the limestone and with access of air, suffers com- 

 plete nitrification with the fixation of the nitric acid by the lime. 

 Large quantities of this guano are also due to the debris of 

 insects, fragments of elytra, scales of the wings of butterflies, 

 etc., which are brought together in those places by the millions 

 of cubic meters. The nitrification, which takes place in these 

 deposits, has been found to extend its products to a distance of 

 several kilometers through the soil. In some places the quan- 

 tity of the nitrate of lime is so great in the soils that they are 

 converted into a plastic paste by this deliquescent salt. 



258. Deposits of Nitrates. The theory of Muntz and Marcano 

 in regard to the nitrates of soils, especially in the neighborhood 

 of caves, is probably a correct one, but there are many objections 

 to accepting it to explain the great deposits of nitrate of soda 

 which occur in many parts of Chile and other parts of the world. 

 Another point which must be considered also, is this : That the 

 process of nitrification can not now be considered as going on with 

 the same vigor as formerly. Some moisture is necessary to nitri- 

 fication, inasmuch as the nitrifying ferment does not act in perfect- 

 ly dry soil, and in many localities in Chile, where the nitrates are 

 found, it is too dry to suppose that any active nitrification could 

 now take place. 



The existence of these nitrate deposits has long been known. 53 

 The old Indian laws originally prohibited the collection of the 

 salt, but, nevertheless, it was secretly collected and sold. Up to 

 the year 1821, soda saltpeter was not known in Europe except 

 as a laboratory product. About this time the naturalist, Mari- 

 ano de Rivero, found on the Pacific coast, in the Province of 

 Tarapaca, immense new deposits of the salt. Later the salt was 

 found in equal abundance in the Territory of Antofogasta, and, 

 further to the south, in the desert of Atacama, which forms the 

 Department of Taltal. 



M Journal of the Royal Agricultural Society, 1852, 13 : 349. 



