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 flame 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. 

 IncUndesence 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. Why, if you hold any thing immediately over the 

 flame, will the Jlame lengthen ? 



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

 maintain a temperature which increases the combustion at the 

 point of the flcime. 



252. Wliy should persons whose clothes takejire, throw 

 themselves down ? 



Because flame spreads most rapidly in an upward direction. 



253. WTiy should persons whose clothes are on jire roll 

 slowly about when they are down ? 



Because they thereby p ress out the fire. 



254. Why does pressing a Jlame 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 ivick turn Hack as it turns ? 

 Because it consists principally of carbon. 



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

 meets the air, does it exhibit a bright spark ? 



Because the carbon of the wick comes into immediate contact 

 with the oxygen of the air. 



257. Why does holding a candle " upside down' 1 put it 

 out? 



