CHAP. 2. 3. OF CLOUDS. a3 



distinct modifications; so each modification lias 

 certain particular varieties into which it forms 

 itself on different occasions, and the meteorolo- 

 gical speculator may be assisted, by having some 

 of the principal of these pointed out to him. 



The varieties of the cirrostratus are nume- 

 rous; but throughout all of them this cloud 

 preserves its distinguishing characteristics; 

 namely, shallowness, and extent in proportion 

 to the quantity of its substance; generally a 

 horizontal position, and a tendency to alter its 

 form and to subside. It is often lower down 

 than a cirrus in the same sky, and a change from 

 that cloud to cirrostratus is usually attended 

 with a diminution of its altitude, a greater 

 degree of density in its fibres, and in a more 

 regularly horizontal position. The plane sheets 

 of Wanecloud are the most simple of its forms ; 

 when these are not extensive, and are seen 

 in the distance, they often look like a dense 

 streak drawn along near to the horizon ; but 

 distinguishable from streaks of cirrus. There are 

 some peculiar appearances of this kind, which, 

 swelling somewhat in the middle, and seen 

 below a more thin and extensive sheet of cloud, 

 give the idea of the back of a great Dolphin 

 rising out of the Ocean, It is in the thin and 



