on the
other side of the Andes to the north-east. Those boundless deserts,
full of organic life, are, like the Puna, among the most interesting
characteristics of the New World.

The climate of these regions is not less rigorous than that of the high
mountain ridges. Cold winds from the west and south-west, blow nearly
all the year round from the ice-topped Cordillera; and for the space of
four months these winds are daily accompanied by thunder, lightning, and
snow-storms. The average state of the thermometer during the cold season
(which is called summer, because it then seldom snows) is, during the
night, -5 deg. R.; and at midday, +9 deg. 7' R. In winter the mercury seldom
falls during the night below freezing point, and it continues between
+1 deg. and 0 deg. R.; but at noon it ascends only to 7 deg. R. It is, however,
quite impossible to determine with precision the medium temperature of
these regions. For the space of a few hours the heat will frequently
vary between 18 deg. and 20 deg. R. The transition is the more sensibly felt on
the fall of the temperature, as it is usually accompanied by
sharp-biting winds, so keen, that they cut the skin on the face and
hands. A remarkable effect of the Puna wind is its power of speedily
drying animal bodies, and thereby preventing putridity. A dead mule is,
in the course of a few days, converted into a mummy; not even the
entrails presenting the least trace of decomposition.

It frequently happens that, after being long exposed to these cold
winds, the traveller enters warm atmospheric currents. These warm
streams are sometimes only two or three paces, and at other times,
several hundred feet broad. They run in a parallel direction with each
other, and one may pass through five or six of them in the course of a
few hours. On the level heights between Chacapalpa and Huancavelica, I
remarked that they were especially frequent during the months of August
and September. According to my repeated observations, I found that these
warm streams chiefly follow the direction of the Cordillera; namely,
from S.S.W. to N.N.E. I once travelled the distance of several leagues
through a succession of these currents of warm air, none of which
exceeded seven-and-twenty paces in breadth. Their temperature was 11 deg. R.
higher than that of the adjacent atmosphere. It would appear they are
not merely temporary, for the mule-drivers can often foretel with
tolerable accuracy where they will be