48 OF CLOUDS. CHAP. 2. 1. 



markably conspicuous in some cirri, which I 

 saw from Farningham, in Kent, about 6 o'clock 

 Tuesday evening, the 1 6th of July, 1811. They 

 pointed nearly to the East. The weather which 

 preceded them was variable, with some showers, 

 and they were succeeded by several days of fair 

 dry weather with various clouds, at the end 

 of which time happened a hard thunderstorm 

 about three in the morning. Can this motion 

 possibly be the effect of an effort on the part of 

 the electrified particles of the cloud, to equalize 

 their own electricity with that of the air ? or 

 may there be some disturbance in the elec- 

 tricity within the cloud, from other causes? 

 Sometimes portions of the cloud seem lightly 

 agitated, as if by partial but gentle draughts of 

 wind. Can the motion alluded to be caused by 

 the evolution of any air generated in the cloud? 

 When the cirrus ceases to conduct, it changes 

 its form, and becomes some other cloud, as has 

 been said : thus, sometimes a sky full of cirrous 

 streaks, after a while becomes overspread with 

 a milky whiteness. This is a sort of change 

 to cirrostratus, which often ends in Rain.* 



* The Abbe Bertholon probably alludes to the cirrus, as 

 well as to scudlike cumulus, and other transitory features of 

 the modifications, which appear in the intervals of showers, 



