RUM. PARASITIC CLOUDS. 475 



of the hill, which gave it the power of retaining a covering 

 of vapour within the sphere of its influence. On the 

 occasion to which I allude the true nature of this very 

 common phenomenon was apparent; while a beautiful 

 example of the formation of clouds in a transparent 

 atmosphere was at the same time presented; attended 

 with other circumstances less easy of explanation. 



The wind was north-east, and the breeze, which had 

 blown moderately all the day, began to freshen con- 

 siderably as the sun went down. Not a cloud was to be 

 seen in the whole hemisphere while the sun was above 

 the horizon. The island of Rum was about three miles 

 to the westward, and its two most remarkable summits 

 Halival and Haiskeval were visible, the vessel being in 

 such a position beating to windward as to preserve a 

 parallel with the current of wind and the land. Shortly, 

 a cloud appeared hovering over one of the mountains, 

 and maintaining a constant distance at an elevation of 200 

 or 300 feet above it ; never approaching or receding from 

 it materially, while a similar cloud involved the other, 

 resting on and surrounding its sides at a considerable 

 distance below the summit. The freshness of the breeze 

 seeming to be at variance with this appearance, I was 

 induced to watch it more narrowly. The detached cloud 

 was perpetually undergoing various and rapid changes ; 

 altering its form, magnitude, and density, in a most capri- 

 cious manner, but still maintaining its distance from the 

 top of the hill. After observing it for an hour, it was 

 perceptible that it was receiving a constant increase at 

 one end, and undergoing a constant corresponding dimi- 

 nution at the other ; its average size remaining the same. 

 On the side from which the wind came, a thin faint 

 vapour began to form at a certain distance from the 

 mountain. This gradually increased in size and density 

 as it drew nearer, and having arrived at a point over the 

 top of the mountain it appeared to have acquired its 

 maximum, forming a thick black cloud. In a minute or 



