226 
NITRATE OF SODA DEPOSITS OF SOUTHERN PERU. 
part of it taken to Liverpool, but was returned as unsaleable in 
England. A cargo was then sent to France, and in 1831 another 
to England, where it became better known, and sold as high as 
80s. to 40s. the cwt. Its price has varied very much ; present 
quotations (1851) about 15s. Since 1830 to 1850, the ex- 
ports of nitrate from Iquique, have been 5,293,478 quintals, 
equal to 239,860 tons; some of it being used as a fertilizer of land, 
some in the manufacture of nitric acid. 
The principal deposits of nitrate of soda yet known, are found 
on the western side of the Pampa de Tamarugal, commencing 
immediately where the level plain ceases, and on the sides of 
some of the ravines running from the Pampa towards the coast, 
and in some of the hollows of the mountains. The nitrate has 
not been found nearer to the coast than eighteen miles, and looks 
as if it gradually transferred itself into salt as it approached the 
coast. The officinas, or refining works are divided into northern 
and southern salitres ; the old salitres being about the centre of 
the former, and La Nueva Norvia that of the latter ; there are 
in all about one hundred. 
The nitrate deposits commence about Tiliviche, and extend 
S. near to Quilliagua, with interruptions of deposits of common 
salt. The nitrate caliche grounds vary in breadth ; the average 
may be five hundred yards, and in places seven or eight feet 
thick, and sometimes quite pure. In the ravines and hollows, 
before mentioned, the nitrate is found on the shelving sides ; the 
hollows look like dried up lakes, and are covered with salt two or 
three feet thick, and on the margin there is nitrate of soda, oft- 
times going down to some depth ; in others ther3 is a hard crust 
upon it, occasionally four feet thick. The nitrate caliche found 
under this crust is in thin layers, and so solid and pure as to be 
sought for, although the expense of blasting is very great. 
There are several varieties of the nitrate of soda caliche ; the 
following being the principal : 
1. White compact, containing sixty-four per cent. 
2. Yellow, occasioned by salts of iodine, seventy per cent. 
3. Grey compact, containing a little iron and a trace of io- 
dine, forty-six per cent. 
4. Grey crystalline, the most abundant variety, contains from 
twenty to eighty-five per cent., affording traces of iodine, with 
one to eight per cent, of earthy matters. 
