nd deposits
them in pointed ridges on either side. The heavier material remains
stationary at night while the lighter particles are rolled downhill,
but the whole mass travels slowly uphill again during the gales of
the following afternoon. The result is the beautiful crescent-shaped
medano.

About five o'clock our mules, a fine-looking lot--far superior to any
that we had been able to secure near Cuzco--trotted briskly into the
dusty little plaza. It took some time to adjust the loads, and it was
nearly seven o'clock before we started off in the moonlight for the
oasis of Vitor. As we left the plateau and struck the dusty trail
winding down into a dark canyon we caught a glimpse of something
white shimmering faintly on the horizon far off to the northwest;
Coropuna! Shortly before nine o'clock we reached a little corral,
where the mules were unloaded. For ourselves we found a shed with
a clean, stone-paved floor, where we set up our cots, only to be
awakened many times during the night by passing caravans anxious to
avoid the terrible heat of the desert by day.

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FIGURE

Mt. Coropuna from the Northwest
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Where the oases are only a few miles apart one often travels by day,
but when crossing the desert is a matter of eight or ten hours'
steady jogging with no places to rest, no water, no shade, the pack
animals suffer greatly. Consequently, most caravans travel, so far
as possible, by night. Our first desert, the pampa of Sihuas, was
reported to be narrow, so we preferred to cross it by day and see
what was to be seen. We got up about half-past four and were off
before seven. Then our troubles began. Either because he lived in
Arequipa or because they thought he looked like a good horseman,
or for reasons best known to themselves, the Tejadas had given
Mr. Hinckley a very spirited saddle-mule. The first thing I knew,
her rider, carrying a heavy camera, a package of plate-holders, and
a large mercurial barometer, borrowed from the Harvard Observatory,
was pitched headlong into the sand. Fortunately no damage was done,
and after a lively chase the runaway mule was brought back by Corporal
Gamarra. After Mr. Hinckley was remounted on his dangerous mule we
rode on for a while in peace, between cornfields and vineyards, over
paths flanked by willows and fig trees. The chief industry of Vitor is
the making of wine from vines which date back to colonial days. The
wine is aged in huge jars, each o