Meteors. 1 1 1 



when the horizon is suddenly overcast, 

 and a copious torrent of rain ensues, which 

 cannot be from the rising of any aqueous 

 vapours at the time, but must be from a 

 precipitation of water that existed in an 

 invisible state in the atmosphere. 



Water may therefore exist in air ; 1st, 

 in an invisible state, which is the case when 

 the dissolving power of air is considera- 

 ble ; 2dly, in a state of incipient separa- 

 tion, in which case it forms clouds, mists ^ 

 or fogs ; 3dly, and lastly, in a state of ac- 

 tual separation, in which case it forms ei- 

 ther rain, properly so called, or snow, or 

 hail. 



Clouds are those well known assembla- 

 ges of vapours that float in the atmosphere, 

 have different degrees of opacity, which 

 arise from their extent and density, and 

 generally have pretty well defined boun- 

 daries. Their height above the surface 

 of the earth (we mean not above the moun- 

 tains) is various, but hardly ever exceeds 

 a mile or a mile and a half. In hot wea- 

 ther, or hot climates, the clouds, being 

 more rarefied, are lighter, and ascend 

 much higher than they do in colder cli- 

 mates, or colder weather : and indeed, in 



