252 SOLAR PHENOMENON, 



seemed to be perfectly aware of its demulcent effect 

 in allaying thirst, and insisted that in the absence 

 of water, it was a sufficient substitute. When I 

 thought upon the numerous instances of benevolent 

 adaptations for our happiness and convenience in 

 other more favoured spots, I could not help reflect- 

 ing, experienced as I was in the scanty resources of 

 a desert, how much more striking, in such situa- 

 tions, were these extraordinary provisions against 

 human suffering in cases of extremity. 



On returning to the camp my attention was di- 

 rected to a singular phenomenon. Exactly over head 

 was a large circular cloud, like a huge shield, in 

 the centre of which the sun shone with a subdued 

 light, a brilliant boss. The outer circle or edge of 

 the cloud was of a bright silver colour, then a 

 narrow band of dull yellow, and the remainder, 

 until it reached the bright centre, was as black as a 

 heavy thunder-cloud. Its diameter was about one- 

 fourth of the sky. In about an hour it gradually 

 disappeared, leaving for a short time afterwards a 

 perfectly circular rainbow around the sun, at the 

 distance of its original circumference. I observed, 

 that although the sun seemed to shine very brightly, 

 as if through an aperture in the centre of this 

 singular appearance, it cast no shadow, and also 

 that the air was much cooler during its continuance. 

 It frequently occurs in Adal, and appears to depend, 

 like the halo around the moon, upon the moisture 

 in the atmosphere. 



