70 THE EEASON WHY. 



" Lord, what is man that thou takest knowledge of him ! or the son of man, 

 that thou makest account of him." PSALMS CXLIV. 



Because the melted grease runs down too rapidly, and at too low 

 a temperature to undergo combustion. It therefore reduces the 

 heat, and extinguishes the flame. 



258. Why is it more difficult to How out the flame of a 

 candle with a cotton wick than one with a rush wick ? 



Because the cotton wick imbibes more of the combustible 

 materials, and holds in its loose texture the inflammable gases in a 

 state ready for combustion. 



259. Why does blowing sharply at a candle flame put it 

 out? 



Because the breath drives away the vapour of the grease which, 

 becoming gaseous, supports the flame. 



And because too rapid a flow of cold air reduces the temperature 

 below the point at which combustion can be maintained. 



260. Wliy will a gentle puff of breath, if given speedily 

 after the flame is extinguished, re-kindle it ? 



Because the oxygen of the air combines with the carbon and hydro- 

 gen that are still escaping from the heated wick, and re-lights it. 



261. Why will not a similar puff re-kindle the flame of 

 a rushlight? 



Because its wick retains but little heat, and holds a comparatively 

 small amount of combustible matter in a volatile state. 



262. Why is a flre, when it is very low, sometimes put 

 out by blowing it ? 



Because the too rapid flow of cold air reduces the temperature of 

 the burning mass. 



263. Why will a piece of paper twisted like an 

 extinguisher put out a candle? 



Because, before the flame of the candle can ignite the paper, the 

 oxygen contained within it is consumed, and the flame iy 

 suffocated. 



