1854.] On the Mirage of India. 165 



The ordinary Mirage of India occurs at distances of from three to 

 eight miles. But from the foregoing observations, it must be manifest 

 that the effect may be produced at distances so remote, as that the 

 substance is completely hidden in the convexity of the earth, and only 

 the reflected image is seen suspended in the air. Of such an effect 

 the Fata Morgana are an instance. And the pictures of coming 

 vessels hanging in the clouds, as seen from the Isle of France, are 

 another. See PI. VII. and PI. VIII. fig. 1st. 



In order to witness the Mirage, it is necessary, I believe, that the 

 back of the spectator be turned upon the sun, otherwise the light 

 reflected from objects in the landscape, will not be sufficiently strong 

 to reach the eye after a second reflection from the canopy of vapor. 



It is impossible to give any adequate idea of the appearances exhi- 

 bited by the Mirage, without the aid of colours. In India the most 

 general appearance is that of a long range of cliffs standing to west- 

 ward of the spectator. These cliffs are of so substantial an appearance 

 so marked with rents and fissures, so tufted with bushes, shrubs and 

 lichens ; so clear and distinct of outline, that it is scarcely possible for 

 an unpractised eye to doubt their reality. 



The effect seems to be produced thus. The mass of the vapor being 

 transparent, reflects objects not only from its lower surface, but 

 throughout its substance. Where the reflections terminate, near the 

 upper surface of the stratum, a succession of terminations in a hori- 

 zontal line give the appearance of a horizontal ledge or table from 

 which hang reversed the reflections of all the images in the landscape, 

 most strongly delineated above (i. e. near this ledge) and decreasing 

 in distinctness downward. Just before their termination, they are 

 met by the summits of the objects themselves, and together they form 

 a faithful representation of the shadows and stains exhibited by cliffs. 

 Trees are the objects most commonly pictured by the Mirage ; the 

 darkness of their hue enabling them to be seen at long distances. 

 These when large, form gigantic columns of dark shadow, melting 

 wavily into the substances of which they are the reflections. But 

 sometimes the monotonous aspect of the cliff is diversified and enlivened 

 by the presence of a white town or of moving objects. Every stump 

 of a tree becomes a palm or a column. Every little bush becomes a 

 tall mass of foliage. The imaginary cliffs are clothed with the richest 



