10 ELECTRICITY. 



Q. Why do we hear the collapsing of the air 

 NEAREST the earth FIRST ? 



A. Because sound takes a whole 

 second of time to travel 380 yards ; but 

 the air is ripped from top to bottom 

 instantaneously : if, therefore, the cloud 

 were 1000 yards off, we should hear the 

 collapsing of the lowest strata nearly 

 three seconds, before we heard that in 

 the immediate vicinity of the cloud. 



Q. Why is the THUNDER sometimes like a 

 deep GROWL ? 



A. When the storm is far distant, 

 the thunder sounds like a deep growl. 



Q. Does not SCENERY affect the sound of 

 thunder ? 



A. Yes ; the flatter the country, the 

 more unbroken the peal : Mountain 

 scenery breaks the peal, and makes it 

 harsh and irregular. 



Q. What is the cause of ROLLING THUNDER ? 



A. The rolling is produced by the 

 reverberation of the thunder along the 

 massive clouds. 



Q. What is meant by the reverberation ? 



A. The echo. 



