THE REASON WHY. 14 1 



** Lo, these are parts of his ways ; but how little a portion is heard of him ? but 

 the thunder of his power who can understand ?" JOB xxv. 



lightning strike out in different directions, causing the sounds of 

 thunder to reach us from varying distances. 



618. Why has the thunder-peal sometimes a low grumbling 

 noise ? 



Because the electrical discharges, though violent, take place far 

 away, and the vibrations of the air become subdued. 



619. Why does the thunder-peal sometimes follow imme- 

 diately after the flash of lightning ? 



Because the discharge of electricity takes place near the hearer. 



620. Why does the thunder-peal sometimes occur several 

 seconds after the flash ? 



Because the discharge takes place far away, and light travels with 

 a much greater velocity than sound. 



621. Through what distance will the sound of thunder 

 travel ? 



Some twenty or thirty miles, according to the direction of the 

 wind, and the violence of the peal. 



622. Through what distance will the light of lightning 



travel ? 







The light of lightning, and its reflections, will penetrate through 

 a distance of from a hundred andjifty to two hundred miles. 



623. How may we calculate the distance at which the 

 electric discharge takes place? 



Sound travels at the rate of a quarter of a mile in a second. If, 

 therefore, the peal of thunder is he-ird four seconds after the flash 

 of lightning, the discharge took place about a mile off. The pulse 

 of an adult person beats about once in a second; therefore, guided 

 by the pulse, any person may calculate the probable distance of tha 

 storm : 



2 beats, | a mile. 



3 beats, f of a mile. 



4 beats, 1 mile. 



