ON THE FORMATION OF CLOUDS. 393 



was recruited on its eastern edge, by a condensa- 

 tion of vapour from the clear part of the atmo- 

 sphere. I watched this process for some hours, 

 which was really beautiful. Nothing could be 

 better calculated to give an idea of creation out 

 of an apparent nonentity, than the continual for- 

 mation of a dense cloud from the invisible vapour 

 of a clear sky. 



During the afternoon another phenomenon, of 

 the same class, made its appearance. The western 

 cloud, previously observed over this side of the 

 river, had entirely disappeared ; and one solitary 

 insulated cloud hovered over head. The breeze 

 still kept up, and this cloud kept its position. Its 

 length might perhaps be a mile and a half, and its 

 breadth three or four hundred yards. Having a 

 pocket compass with me, I ascertained that its 

 length was as nearly as possible in the magnetic 

 meridian, almost at right angles to the direction of 

 the wind. The phenomena displayed by this cloud 

 were really interesting. It was dense in the middle, 

 but ragged and thin at the edges. It was fed by 

 the condensation of vapour on its eastern edge, 

 and as continually wasted on its western edge by 

 the re-dissolution or rc-attcn nation of that vapour. 

 The axis of the cloud remained in nearly the same 

 3 E 



