^g THE NATUBAl. BISTOaY QF CfcOUBS. 



Kiilxd. to t*lte the opportunity of examiiving a shower in profile at 



it approaches from the horizon. He will see the dense' 

 gloom, which exoerience teaches him to regard as a mass of 

 descending rain, losing itself above in a clood, which com- 

 monly spreads in one continuous sheet to a j^reat distance all 

 around the shower; insomuch that while the latter is on the 

 horizon at several rtiiles distance, the edge of the cloud has 

 frequently arrived in the zenith. He will perceive, that thi» 

 spreading crown of the shower advances regularly before it, 

 and that, whether viewed from a distance or over-head, it 

 exhibits in a greater or less degree the fibrous structure of 

 the cirrus. After the shower has passed over, he will cora- 

 monly observe the same appearances in the part of the cloud 

 which follows it; anci in squally weather he will sometimes 

 be able t*o repeat these observations on many different 

 showers appearing successively ; or at the same lime, in dif- 

 ferent quarters. The term nimbus is intended strictly to de- 

 note no more than this verted cone of cioud, from xvhich a 

 sudden or dense local . jwer, whether of rain, snow, or hail, 

 for the difference is not essential in either case, is seen td 

 descend. As it rises to a great height in the atmosphere, it 

 maybe seen from a distance of many miles ; and ^o constant 

 is the result of a shower arriving with it, that though, in 4, 

 few instances, perhaps from the small quantity of the rain, 

 we have not been able to discover the usual obscurity b^ 

 feeath it, while at a distance, we believe it may be laid down 

 as a general rule, on as good grounds as in most other cases, 

 that rain, snow, or hail, is falling on the tract over which it 

 i& sptead. 



" Qualis ubi ad terras abrupto sidere nimbus 

 It mare per medium, miseris heu prescia lotigc 

 Horrescunt corda agricolls." "Virgil. 



So while far off at sea the storm-cloud lowers. 

 And on the darken'd wave its fury pours. 

 Mid crops unreap'd the hapless peasants stand, 

 And shuddering view its rapid course to land. 



There is a great difl'erence, at different times, in the pro* 

 |)Ortion which the inverted cone ofcloud bears to the column 

 ©f rain, &c., in which it terminates ; and in a very turbid and 



moiat 



