THE REASON WHY. 14] 



'Lo, these we 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 lias 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 tliejlash ? 



Because the discharge takes place far away, and llglit 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 

 tvind^ 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 andffty 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 heird 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 tht 

 eCorm : 



2 beats, | a mile. 



3 beats, f of a mile. 



4 beats, 1 mile. 



