166 On the Mirage of India. [No. 2. 



verdure, stolen from green corn fields drawn up aloft as by enchant- 

 ment to garnish the fairy structure. Small, white, moving figures, 

 otherwise scarcely noticed by the eye, become stalking ghosts whose 

 heads are lost in ether. Villages far buried beneath the convexity of 

 the earth's surface are seen hanging reversed in the air, and should 

 any small river with its boats be flowing there, all the shifting scenery 

 would be presented in the clouds : the white sails, greatly magnified, and 

 distorted, having a truly spectral appearance, as they hover silently by. 



With respect to the Mirage of the Isle of France, the vapor hanging 

 over the sea is probably more transparent and of higher elevation than 

 that which overhangs the land. In this case the sails of a vessel 

 brightly illuminated by the sun, might be seen at the distance of a 

 hundred or more miles. If at a hundred miles, then the reflecting 

 canopy must be distant fifty miles from the spectator's eye. The 

 canopy is not a perfect plane, but is a mirror slightly concave answer- 

 ing to the convexity of the earth. The image therefore would proba- 

 bly be magnified in the concave mirror which would somewhat balance 

 the loss of size sustained in transit from so great a distance. The 

 vapor is not visible excepting by its effects. Visible vapor does not 

 reflect a perfect image of any object. The same difference seems to 

 exist between visible and invisible vapor as between snow and ice. 

 The first is opaque and unpolished, the latter polished and transpa- 

 rent. And the proper distinction perhaps were to call the first mist, 

 the latter vapor. 



I one morning in November observed the sun rise through a mirage 

 vapour. As the upper limb reached the stratum, it was drawn up 

 from its convexity, was straitened and distorted. When the vapour 

 cut the centre it presented the appearance delineated in Plate VIII. 

 fig. 2nd. Yet the brilliance of the disc was little impaired in the 

 centre. 



Owing to the necessity of a clear substratum of atmosphere, it is 

 seldom that mirage can be exhibited over a large city. But when 

 once acquainted with its laws and phenomena, it were easy to imagine 

 the glorious apparition which such a city as London would present 

 reflected in mirage. If seen from a considerable distance, the whole 

 city would seem inverted and suspended from the clouds. The spires 

 and domes and towers would be drawn downward toward the earth. 



