CHAP. 1. 2. OF CLOUDS. 



SECTION II. 



Of the Cirrus or Curkloud. PI. I. Fig. 1. 

 CIRRVS. Def. NVBES CIRRATA TENVISSIMA QVAE 



VNDIQVE CRESCAT. 



THE cirrus is a cloud which appears to have 

 the least density, and generally the most eleva- 

 tion, and which has the greatest variety of extent 

 and direction. It may truly be called the Pro- 

 teus of the skies; for, in some kinds of weather, 

 its figure is so rapidly and so continually 

 changed, that after turning the eye away from 

 it for a few minutes, it will frequently be found 

 so completely altered, as scarcely to be identified 

 as the same cloud. This, however, is not always 

 the case; it is sometimes visible for many hours 

 and even days together, without much changing 

 its appearance. I shall briefly mention some of 

 its most common varieties, together with the 

 circumstances under which they generally ap- 

 pear. 



After a continuance of clear weather, the 

 cirrus is frequently the first cloud which is seen. 

 In this case it often looks like a fine whitish 

 thread pencilled, as M. Howard expresses it, 



