170 CONDUCTION. 



really of the same temperature ; but 

 some feel colder than others because they 

 are better conductors. 



Q. How LONG will the hearth-stone feel cold 

 to the feet resting on it ? 



A. Till the feet and the hearth-stone 

 are both of the same temperature ; and 

 then the sensation of cold in the hearth- 

 stone will go off. 



Q. Why would not the HEARTH-STONE feel 

 COLD, when it is of the SAME temperature as our 



FEET? 



A. Because the heat would no longer 

 rush out of our feet into the hearth-stone, 

 in order to produce an equilibrium. 



Q. Why does the HEARTH-STONE (when the 

 fire is lighted} feel so much HOTTER than the 



HEARTH-RUG ? 



A. The hearth-stone is an excellent 

 conductor; and, therefore, parts with its 

 heat more readily than the woollen 

 hearth-rug; which (being a very bad 

 conductor^ parts with its heat reluctantly. 



Q. Why does PARTING with HEAT RAPIDLY 

 make the HEARTH-STONE/^ WARM? 



A. As the heat of the stone rushes 



