38 ASPECTS OF TROPICAL NATURE 



day from their previous exhaustion. In general, a healthy 

 man can withstand hunger and thirst during four or five days, 

 but only in a temperate climate and when the body is at rest ; 

 while in the burning deserts of Peru, the want of water during 

 forty-eight hours, combined with the fatigue of wading through 

 the deep sands, can only end in death. Thirst can, undoubtedly, 

 be supported ten times longer in the moist sea-air than in the 

 thoroughly desiccated atmosphere of a tropical waste. The 

 dangers of these solitudes are increased by the great mobility 

 of the soil. When a strong wind blows, huge sand-columns, 

 rising like water-spouts to a height of eighty or a hundred feet, 

 advance whirling through the desert, and suddenly encompass 

 the traveller, who can only save himself by a rapid flight. Such 

 is the instability of the soil, that in a few hours a plain will be 

 covered with hillocks or Medanos, and recover after a few days 

 its former level. The most experienced muleteers are thus con- 

 stantly deceived in their knowledge of the road, and are the first 

 to give way to despair, while seeking to extricate themselves from 

 a labyrinth of newly-formed medanos. These constant transfor- 

 mations and shiftings in the desert, which Tschudi graphically 

 calls " a life in death," take place more particularly in the hot 

 season, when the least pressure of the atmosphere suffices to 

 disturb the dried-up sands, whose weight increases during the 

 winter by the absorption of moisture. The single grains then 

 unite to larger masses, and more easily withstand the pressure 

 of the wind. 



The summer, or dry season, begins in November. The rays 

 of the vertical sun strike upon the light-coloured sands, and are 

 reflected with suffocating power. No plant, except the cactuses 

 and tillandsias, which manage to thrive where nothing else 

 exists, takes root in the glowing soil : no animal finds food on 

 the lifeless plain ; no bird, no insect, hovers or buzzes in the 

 stifling atmosphere. Only in the highest regions the condor, 

 the monarch of the air, is seen sailing along in lonely majesty. 



In May, which in these southern latitudes corresponds to our 

 October, the scene changes. A thin, misty veil extends over 

 the sea and the coast, and, increasing in density during the 

 following months, only begins to diminish in October. At the 

 beginning and the end of this damp season the mist generally 

 ascends between nine and ten in the morning, and falls again 



