TRANSACTIONS OF THE SECTIONS. 103 
all over this plain, as well as those in the Desert of Atacama. A curious point 
about the greater portion of the water obtained from the wells in this plain is, that 
although there is so much saline material on the sutface, there is little or none of it in 
the water. It is in this plain, where there is so great an abundance of salt, nitrate of 
soda, sulphate of soda (Glauberite), carbonate of soda (Trona), sulphate and mutiate 
of lime, and a newly-discovered salt of borax (Hayesine or Hydro-boro-calcite), this 
valuable salt is found with and under the beds of nitrate of soda, and often in company 
with Glauberite*. With the nitrate of soda, in particular, there are iodic salts}, and 
probably bromic. In the hills, on either side of this plain, are large quantities of 
native alum or Pickeringite. 
The formation of nitrate of potash in India, and nitrate of soda in South America, 
is difficult to explain. It was formerly supposed that the nitrogen required to pro- 
duce the nitrate of potash in India came from the decomposition of organic matters ; 
but as the greater portion of nitrate of potash was found in situations affording none, 
this opinion was abandoned, and the nitrogen of the atmosphere was resorted to. 
With regard to the formation of nitrate of soda in South America, at least in South 
Peru, there are no organic matters whatever in the soil from the Andes to the sea- 
shore; for the whole country is, and has been for ages, arid, rocky, sandy, and marly 
saliferous deserts. The nitrogen and oxygen of the air may possibly yield, in some way 
or other, nitric acid, when assisted by tropical heat, the chemical rays of the sun and 
Moisture ; still, if we have to look to volcanic sources for the formation of Salt and 
other chlorides, why not recur there also for the origin of the nitrates, sulphates, 
borates, iodates, &c.? 
A short remark on the probable cause of the South Peruvian deserts may not be 
out of place here. The S.S.E. wind, having been deprived of much of its humidity 
in traversing the continent of America, arrives in the frozen regions of the Andes, so 
dry as not to be in a position to deposit any moisture of consequence; and this dry 
or S.S.E. wind blowing across the lands of the west coast, appears to be the main 
cause of its present desert character. 
The nitrate of soda has as yet only been met with on the western side of the Pampa 
de Tamarugal, and the deposits of it have interruptions or spaces covered with salt, 
The nitrate grounds vary in breadth, but are of great length, and in places 7 to § feet 
thick, sometimes quite pure. 
The Caliche, or rough nitrate of soda, is boiled in water, the nitrate is held in solu- 
tion, whilst the salt and earthy parts fall to the bottom of the boiler: the saturated 
solution is run into troughs to erystallize, and is then ready for sale. 
The principal occupation of the Province of Tarapaca is in the nitrate of soda trade, 
the article being shipped from Iquique to Europe, where it is used as a fertilizer in 
the manufacture of nitric and sulphuric acids, &c. 
There is sufficient nitrate for the consumption of Europe for ages to come. The 
supply, however, at-present for export cannot be much augmented over 30,000 tons 
annually, in consequence of the scarcity of beasts of burden in this desert country to 
convey it from the oficinas or works to the port of Iquique. Since 1830 to 1851, the 
exports have been about 240,000 tons, one of the principal exporters being Mr. 
G. Smith, to whom the Province is greatly indebted for his pérseverance in esta- 
blishing this new branch of trade. 
Having traversed the Pampa de Tamarugal, ranges of sandstone mountains present 
. *® The boracie acid of Tuscany and borax from India is almost monopolized by one party 
in England; the price for British refined being in November, 1852, £4 to £4 4s. per 
cwt. Now it would be important if supplies of the boro-calcite from Tarapaca could be ob- 
tained. Mr. Smith fears it only exists in small quantities there, but in which opinion I do 
not quite concur. According to his views as to the origin of salt and many other saline 
bodies being volcanic, the author would recommend a search for nitrates, borates, iodates, 
&c., in those dry and desert saline districts, the more particularly where there are evidences 
of volcanic influences. 
+ Hayes found in a sample of nitrate of soda, 0°63 iodic salts, composed of iodaté of soda 
and chloro-iodate of magnesia. 
In November, 1851, dry iodine sold for 64d. to 7d. per oz., but at the same period, 1852, 
it tod risen from 1s. 3d. to ls. 6d. Thus in these salts from Tarapaca we have another source 
of iodine. 
