vi t PREFACE. 



visitor than an inhabitant : lugubrious regions, on whose threshold 

 one might write the legend written, according to Dante, on the gates 



of hell 



" Lasciato ogni speranza, voi ch'entrate." 

 (All hope abandon, ye who enter here.) 



But, on the whole, these true Deserts offer ample material for the 

 admiration of the artist, the meditations of the thinker, the researches 

 of the natui-alist and the physician. Theirs is that kind of beauty 

 which borders on the sublime, and which impresses us so powerfully 

 in the Ocean. And, like the Ocean, they awake in the soul the 

 feeling of infinity. They render it forgetful of the tumultuous 

 regions which are perturbed by petty passions, and vexed by the 

 contentions of ephemeral interests, and transport it to the boundless 

 space and the eternal spheres, or allow it to draw back within itself 

 and muse upon its future destiny. 



Finally, what grave problems does the Desert place before the 

 man of science ! And first, why do life and fertility prevail else- 

 where, here, sterility and death ? Why does an irrevocable curse 

 seem to weigh upon certain parts of the world, while others rejoice 

 in Nature's fairest gifts ? It is by examining the constitution of the 

 soil and the character of the climate that we discover the key to this 

 enigma, and recognize in this apparent anomaly a necessary effect of 

 the harmonious laws of the universe. Then the Desert has a 

 geology and a meteorology of its own ; is the theatre of special 

 phenomena, which we do not observe in more favoured regions. 

 Life itself is not completely absent from it ; specimens of the organic- 

 kingdoms are rare, no doubt, but for this very reason are the more 

 interesting. 



And if, from the Desert properly so called, we pass to those 

 countries where the genial air and the abundant waters favour the 

 action of the productive forces, the interest increases with the 



