THE REASON WHY. 69 



' How oft is the candle of the wicked put out ? and how oft cometh their 

 destruction upon them ?" JOB xxi. 



the flaine of the candle, so as to shut off the light of the more luminous part* 

 the pale fringe around the flame will be found distinctly perceptible. 

 Incandesence means heated to whiteness. 



250. Why does the flame terminate in a point ? 

 Because cold air rushes towards the flame in every direction, and 



is carried upward. At the point where, the flame terminates the 

 cold currents have so reduced the temperature that combustion can 

 no longer be sustained. 



251. WJiy, if you hold anything immediately over the 

 flame, will the flame lengthen ? 



Because, by preventing the rapid escape of the heated air, you 

 maintain a temperature which increases the combustion at the 

 point of the flame. 



252. Why should persons whose clothes talcejire, throw 

 themselves down ? 



Because flame spreads most rapidly in an upward, direction. 



253. WJiy should persons whose clothes are on fire roll 

 slowly about when they are down ? 



Because they thereby press out the fire. 



254. Why does pressing aflame or a spark put it out ? 

 Because it prevents the contact of the flame or spark with the 



oxygen of the air. 



Extinguishers put out tha flame of candles in the same manner. A person 

 dies from " suffocation" through the absence of oxygen ; and it is literally 

 practicable to " suffocate " afire. 



255. Why does the wick turn black as it turns ? 

 Because it consists principally of carlon. 



256. Wliy, when the point of the wick turns out and 

 meets the air, does it exhibit a bright spark f 



Because the carbon of the wick comes into immediate contact 

 with the oxygen of the air. 



257. Why does holding a candle "upside down'" p*t it 

 out? 



