Note 36 — STEPPES AND DESERTS.

p. 18.—“The illusive image of a cool rippling watery mirror.”

The well-known phenomenon of the mirage is called in Sanscrit the “thirst of the gazelle.” (See my Relation historique, T. i. pp. 296 and 625; T. ii. p. 161.) All objects appear to hover in the air, and are at the same time seen reflected in the lower stratum of air. At such times the entire desert assumes the aspect of the wave-covered surface of a wide spread lake. Palm trees, cattle, and camels, sometimes appear inverted on the horizon. In the French expedition to Egypt, the soldiers, parched with thirst, were often brought by this optical illusion into a state of desperation. This phenomenon has been remarked in all quarters of the globe. The ancients were acquainted with the remarkable refraction of the rays of light in the Lybian Desert. I find mention made in Diod. Sic. lib. iii. p. 184, Rhod. (p. 219, Wessel), of extraordinary illusive images, an African Fata Morgana, with most extravagant explanations of the supposed conglomeration of the particles of air.