Page:The Incas of Peru.djvu/241

Rh an immense cloud of sand, rising to a hundred feet and whirling in all directions. When at rest the medanos vary in height from eight to twenty feet, with a sharp crest, the inner side perpendicular and the outer with a steep slope. Scattered over the arid wilderness they form intricate labyrinths, and many a benighted traveller has lost his way among them and perished with his mule, after wandering for days. Such unfortunates form nuclei for new medanos. At early dawn there are musical sounds in the desert. They are caused by the eddying of grains of sand in the heated atmosphere on the sharp crests of the medanos.

Apparently the coast deserts of Peru are destitute of all vegetation. As far as the eye can reach there is a desolate waste. Yet two or three kinds of plants do exist. The smaller medanos are capped with snowy white patches, contrasting with the greyish white which is the colour of the sand. This whiteness is caused by innumerable short cylindrical spikes of an amaranth. Its stems originate in the ground beneath the medano, ramify through it, and go on growing so as to maintain their heads just above the mass of sand. The two other herbs of the desert are species of yuca which form edible roots, but maintain a subterranean existence for years, only producing leafy stems in the rare seasons when moisture penetrates to their roots. Near the foot of the mountains are the tall branched cacti. When the mists set in, the lomas, or chains of