Nature and Art, June 1, 1867. J 
THE DESERTS OF PERU, AND THEIR WEALTH. 
1G7 
sea-water may percolate, or get into hollows, 
chemical changes go on rapidly, and much sulphate 
and carbonate of lime and other salts are found. 
When the sea-water is left in hollows and splits 
amongst the rocks, solar evaporation causes the 
deposit of sea-salt. At Huacho, 11° 8' S., large 
quantities are formed and exported. 
When we pass these mountains of the coast, par- 
ticularly in South Peru, we come upon extensive 
table-lands, from 3,000 to 4,000 feet above the level 
of the sea. Such a one is the extensive Pampa de 
Tamarugal, in the Province of T arapaca, where we 
find so much common salt, nitrate of soda, and borate 
of lime. However, here the saline bodies, I suppose, 
have found their way by percolation with water, 
from the volcanic Andean regions, where there 
are immense plains covered with salt (the salt most 
probably of volcanic origin), one of which I saw 
stretching from 19° 30' S., for about two degrees 
of longitude, and to near the mines of Potosi. 
In the desert, from the port of Islay in 17° S., 
to the city of Arequipa, a distance of 90 miles, the 
sand is mixed with a white dust, in all probability 
thrown out of the volcanoes in that district. The 
decomposition of the trachyte of the valley of 
Yura and A requipa, yields sub-carbonate of soda, 
used in the manufacture of soap. Each 5,000 
square yards of soil is valued at £200, and every 
six weeks a harvest of sub-carbonate of soda is 
reaped. Between the port of Arica in 18° 28' S., 
and Tacna, there is a desert of 50 miles across. 
On examining the sand here, I found it to be 
made up of small but perfect crystals of quartz, 
which shine brilliantly in the sun. What is curious 
is, that there are apparently no quartzose rocks in 
the vicinity of this desert. Can these crystals be 
volcanic 1 
On the route from Tacna to Arequipa, between 
Locumba and Moquegua, it is reported that numer- 
ous recent marine shells are seen in the sand, and 
this track is some considerable distance from the 
sea and much above it. At Paita, in 5° 5' S., 
I noticed cliffs which are from 300 to 400 feet 
above sea-level, composed of horizontal layers of 
sand containing shells, and was informed that as 
far as twenty-four miles inland similar arrangements 
of sand with shells were to be met with. 
I have been describing localities along the desert 
coast of Peru, and a few leagues inland. Nearer 
or farther we come to the real bases of the Andes, 
and having arrived at a certain elevation, we 
find vegetation between mountain ranges, which 
diminishes as further altitude is obtained. We 
traverse the passes of the Cordilleras, and descend 
slightly into the high table-lands, or the Thibet of 
the New World, where we find many lakes, in- 
cluding the large one of Titicaca, surrounded by 
rough pastures. During the summer months, nearly 
every day after meridian, there is lightning and 
thunder, with, at times, rain, hail, or snow ; which 
cause the ravines to convey water to the lower 
country. Hereabouts spring up the mighty mountain 
masses of the Ilimani and others. Continuing in 
an easterly direction, we descend to the wondrously 
wooded and pasture lands that stretch off towards 
La Plata and Brazil. 
We come now to the other great element, namely, 
the atmosphere : we may say, that the lav/s of the 
winds are the bases of the distribution of sterility 
and fertility. 
The warm tropical winds or trades from the east 
are moist, and, blowing against cooler land, they 
deposit their moisture in rain ; consequently, the 
eastern side of South America is the moist side, 
and the western the dry ; a very great extent of its 
coast being completely desert. However, in the 
winter season in Peru, the gentle north-west winds 
from the Pacific bring some little moisture to the 
land. America generally is said to be the forest 
continent, and where there is some lack of moisture, 
there are the great pampas, llanos, and prairies ; 
where the winds are still dryer, there are the 
deserts, as those of California, coming south to 
Peru ; the whole of its coast is in this state ; in the 
north is the extensive desert of Sechura, in the 
south that of Atacama. 
Dana well observes that the great truth is taught 
us by this air and these waters, as well as by the 
lands, that the diversity about us is an exhibition 
of perfect system. If the earth has its barren ice- 
fields about the poles, and its deserts no less barren 
towards the equator, they are not accidents in the 
making, but results involved in Nature’s scheme 
from its very foundation. 
Sand, then, is comminuted rock of any kind ; but 
common sand is mainly of quartz ; thus, according 
to its locality, it forms sand-bars, sand-drifts, sand- 
hills or dunes on sea-shores, and moving sands of 
deserts ; it is of this last form that an illustration 
is offered. 
The rainless coast of Peru * consists of a line of 
deserts from near Tumbez in the north, to the river 
Loa in the south, a distance of some 1,500 miles. 
The same characteristics belong to the coast of 
Bolivia, comprising the coast of the great desert of 
Atacama, which extends into the north of Chile. 
The width of these deserts are from a few miles to 
sixty or eighty, as the branches of the Cordilleras 
approach or recede from the shores of the Pacific. 
Were it not for the stupendous background which 
gives to every other object a comparatively diminu- 
tive outline, the sand-hills might often be called 
mountains. One such example may be seen in 
the rear of the town of Iquique, in 20° 12' S., 
which, when surveying the district with Mr. George 
Smith, we called “ The Elephant,” its outline 
having something the appearance of that animal. 
This long line of sterile country is intersected 
by small streams, the distance between which 
is seldom less than twenty, and in one case is a 
hundred and twenty geographical miles. The 
narrow slips on the banks of a stream are peopled 
in proportion to the supply of water, resulting from 
the little rain and the melting of spare quantities 
of snow and ice in the Andes. Under the Incas 
the system of irrigation by lengthy aqueducts, and 
* See General Miller’s Memoirs. 
