Natural History, 8fc. 201 



a deluge of rain. This appearance was neither preceded nor fol- 

 lowed by any lightning or explosion; the column was vertical 

 and immobile, no rotary movement being observed*. 



29. MIRAGE OF CENTRAL INDIA. 



The following account of the Indian mirage is from Colonel Tod's 

 Ragasthan. It is only in the cold season that the mirage is visible. 

 The sojourners of Maroo call it the see-kote, or 'castles in the air.' 

 In the deep desert, to the westward, the herdsmen and travellers 

 through these regions style it chittrdm, ' the picture ;' while about 

 the plains of the Chumbol and Jumna they term it dessasiir, 4 the 

 omen of the quarter.' This optical deception has been noticed 

 from the remotest times. The prophet Isaiah alludes to it when he 

 says 'and the parched ground shall become a pool;' which the 

 critic has justly rendered ' and the sehrdb shall become real water.' 

 Quintus Curtius, describing the mirage in the Sogdian desert, says 

 that ' for the space of four hundred furlongs not a drop of water is 

 to be found, and the sun's heat being very vehement in summer, 

 kindles such a fire in the sands that everything is burnt up. There 

 also arises such an exhalation that the plains wear the appearance 

 of a vast and deep sea,' which is an exact description of the chit- 

 tram of the Indian desert. But the sehrdb and chittrdm, the true 

 mirage of Isaiah, differ from that illusion called the see-kote, and 

 though the traveller will hasten to it in order to obtain a night's 

 lodging, I do not think he would expect to slake his thirst there. 



When we witnessed this phenomenon, at first the eye was attracted 

 by a lofty opaque wall of lurid smoke, which seemed to be bounded 

 by or to rise from the very verge of the horizon. By slow degrees, 

 the dense mass became more transparent, and assumed a reflecting 

 or refracting power ; shrubs were magnified into trees ; the dwarf 

 khyre appeared ten times larger than the gigantic #m/z of the forest. 

 A ray of light suddenly broke the line of continuity of this yet 

 smoky barrier, and, as if touched by the enchanter's wand, castles, 

 towers, and trees were seen in an aggregated cluster, partly obscured 

 by magnificent foliage. Every accession of light produced a change 

 in the chittram, which, from the dense wall that it first exhibited, 

 had now faded into a thin transparent film broken into a thousand 

 masses, each mass being a huge lens, until at length the too vivid 

 power of the sun dissolved the vision ; castles, towers, and foliage 

 melted like the enchantment of Prospero into ' thin air.' 



But the difference between the sehrab or chittrdm and the see-kote 

 or dessasur is, that the latter is never visible but in the cold season, 

 when the gross vapours cannot rise, and that the rarefaction which 

 gives existence to the other destroys this whenever the sun has 

 attained 20 of elevation. 



* Bib. Univ., June, 1830. 



