36 



THE AIE. 



horizontal layers of clouds low down in the horizon, so 

 often seen at sunset ; and the " nimbus " is the rain-cloud, 

 of a dark grey or leaden hue, with sharp well-marked 

 edges (fig. 6). 



Clouds are amongst the most beautiful as well as useful 

 things in nature, and it is one of the greatest proofs of the 

 active benevolence of Grod, that all those things which serve 

 man the most, are the most beautiful to contemplate. 

 Without clouds there would be no rain, and without this 

 no vegetation. In many parts of the tropical regions there is 

 little or no rain, and in such parts desert places abound. 

 Clouds are often of different states of electricity, and when 

 they come near enough to each other, a transfer of the fluid 

 takes place, accompanied with a flash of lightning (fig. 7) and 

 a report, although this is not always heard at the same time 

 that the lightning is seen, as sound does not travel nearly so 



FIG. 7. 



fast as light ; there is no danger from this kind of lightning. 

 But it sometimes happens that a cloud in an opposite 

 state of electricity to the surface of the earth is near enough 

 to produce a flash of lightning between them, in this case 



