AGUA PRIETA. 
247 
that grew on its banks was reflected from its imaginary 
surface.* Some of our party could not be convinced 
of the illusion, and rode off at full speed to quench 
the thirst of their panting animals. We hardly knew 
what course to take here ; but seeing some bright 
green patches amid the vast plain of gray and parched 
grass, we made directly for it; and great was our joy 
at finding several large holes, dug by parties who had 
preceded us, which were filled to the brim with the 
most delicious water. Near these we encamped. 
The country passed over in the last three days is 
barren and uninteresting in the extreme. As we 
toiled across these sterile plains, where no tree offered 
its friendly shade, the sun glowing fiercely, and the 
wind hot from the parched earth, cracking the lips 
and burning the eyes, the thought would keep sug- 
gesting itself. Is this the land which we have pur- 
chased, and are to survey and keep at such a cost? 
As far as the eye can reach stretches one unbroken 
waste, barren, wild, and worthless. For fifty-two long 
* The well-known phenomenon of the mirage is called in Sanscrit 
“ the thirst of the gazelle.” All objects appear to float in the air, while 
their forms are reflected in the lower stratum of the atmosphere. At 
such times the whole desert resembles a vast lake, whose surface undu- 
lates like waves. Palm-trees, cattle, and camels sometimes appear invert- 
ed in the horizon. In the French expedition to Egypt, this optical 
illusion often nearly drove the faint and parched soldiers to distraction. 
This phenomenon has been observed in all quarters of the world. The 
ancients were also acquainted with the remarkable refraction of the 
rays of light in the Libyan Desert. We find mention made in Diodorus 
Siculus of strange illusive appearances, an African Fata Morgana^ toge- 
ther with still more extravagant explanations of the conglomeration of 
the particles of air. Humboldt. Views of Nature., p. 137. 
