THE BEASON WHY. 77 



' It ia a got d thing to give thanks unto the Lord, and to sing praises tmto thy 

 name, O Most High." PSALM xcn. 



Because the paper is more easily ignited than wood, and wood 

 than coals ; therefore the paper assists the ignition of the wood, 

 and the wood assists the ignition of the coals. 



299. Why will not wood ignite by the flame of a match ? 



It will do so, unless there is a great disproportion between the 

 size of the wood and the flame of a match. A thin piece of wood 

 will ignite, but a square block will not, because the heat of the 

 flame is insufficient to raise the temperature of a large surface to 

 the point that will drive out its gases, 



300. Why do we place the paper under the wood, and the 

 wood'under the coals ? 



Because heat and flame, when surrounded by air, have a strong 

 tendency to spread themselves upwards. 



301. Would it be possible to light the coals ly putting the 

 paper and the wood upon the top ? 



It would be possible ; but the loss of heat would be so great, 

 that a much larger quantity of paper and wood would be required. 



302. Why does a poker laid across the top of a dull fire 

 revive it ? 



Because the poker radiates the heat it receives from the fire 

 downward upon the fuel. 



Because, also, it divides the ascending air, and thereby creates 

 currentt. 



The amount of good which the poker does to the fire is very slight indeed. 

 Generally, the housewife stirs the fire first, and blows or brushes away the 

 ashes that prevent the influx of air. She then places the poker upon the top, 

 and the popular mind supposes that the poker " draws " the fire. The custom 

 of placing a poker over the fire is of very remote antiquity. It was once 

 believed that forming a cross, by placing the poker over the bars, protected the 

 fire from the hostility of malignant witches ! 



303. Why should fire-places be fixed as low as possible in 

 rooms ? 



Because heat ascends, and when the fire-places are high the lower 

 parts of the room are inadequately warmed. 



