CHAP. H. VAHIETIES OF WEATHER. 237 



such clear weather happened during Sept. 1811, 

 and afforded a good opportunity of making 

 observations on the brilliant comet which was 

 conspicuous that autumn. 



A fine line of cirrus, of great altitude and 

 length, is often the first sign that the clear 

 weather above described is about to be changed 

 for an atmosphere more variable ; and in pro- 

 portion as such kinds of cirri increase, and 

 others, or clouds of other modifications, suc- 

 ceed, we may judge of the nearer or more 

 distant approach of the alteration ; and the 

 weather about to follow may, in general, be 

 determined by the general face of the Sky, and 

 of the kind of modifications apparent during 

 the progress of the change. But the great 

 clearness above depicted often gives place to, 

 and alternates with a state of the atmosphere 

 marked by peculiar circumstances, which seem 

 to indicate a great disturbance, and perpetual 

 change in its electric state. 



In such weather, the Curlcloud generally ap- 

 pears soon after, and sometimes before, Sunrise, 

 and prevails through the day, under every con- 

 ceivable variety of whimsical figures. Comoid 

 tufts, like bushes of hair, or sometimes like 

 erected feathers ; angular flexures ; streaks ; 



