are thawed. The existence of this crust of a soluble substance over
the whole face of the country, shows how extraordinarily dry the
climate must have been for a long period.
At night I slept at the house of the owner of one of the saltpetre
mines. The country is here as unproductive as near the coast; but
water, having rather a bitter and brackish taste, can be procured by
digging wells. The well at this house was thirty-six yards deep: as
scarcely any rain falls, it is evident the water is not thus derived;
indeed if it were, it could not fail to be as salt as brine, for the
whole surrounding country is incrusted with various saline substances.
We must therefore conclude that it percolates under ground from the
Cordillera, though distant many leagues. In that direction there are a
few small villages, where the inhabitants, having more water, are
enabled to irrigate a little land, and raise hay, on which the mules
and asses, employed in carrying the saltpetre, are fed. The nitrate of
soda was now selling at the ship's side at fourteen shillings per
hundred pounds: the chief expense is its transport to the sea-coast.
The mine consists of a hard stratum, between two and three feet thick,
of the nitrate mingled with a little of the sulphate of soda and a good
deal of common salt. It lies close beneath the surface, and follows
for a length of one hundred and fifty miles the margin of a grand basin
or plain; this, from its outline, manifestly must once have been a
lake, or more probably an inland arm of the sea, as may be inferred
from the presence of iodic salts in the saline stratum. The surface of
the plain is 3300 feet above the Pacific.
19th.--We anchored in the Bay of Callao, the seaport of Lima, the
capital of Peru. We stayed here six weeks but from the troubled state
of public affairs, I saw very little of the country. During our whole
visit the climate was far from being so delightful, as it is generally
represented. A dull heavy bank of clouds constantly hung over the
land, so that during the first sixteen days I had only one view of the
Cordillera behind Lima. These mountains, seen in stages, one above the
other, through openings in the clouds, had a very grand appearance. It
is almost become a proverb, that rain never falls in the lower part of
Peru. Yet this can hardly be considered correct; for during almost
every day of our visit there was a thick drizzling mist, which was
sufficient to make the streets muddy and one's clothes damp: this the
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