POLISHED METAL. 193 



A. Because light coloured and highly 

 polished metal makes the best of all 

 reflectors. 



Q. Why do not PLATE-WARMERS BLISTER 

 and scorch the WOOD behind ? 



A. Because the bright tin front 

 throws the heat of the fire back again, 

 and will not allow it to penetrate to the 

 wood behind. 



Q. If metal be such an excellent CONDUCTOR 

 of heat, how can it REFLECT heat, or throw it off? 



A. Polished metal is a conductor of 

 heat, only when that heat is communicated 

 by actual contact; but whenever heat 

 falls upon bright metal in rays, it is 

 reflected back again, and the metal 

 remains quite cool. 



Q. What is meant by " heat falling upon 

 metal IN RAYS," and not "by contact" ? 



A. If a piece of tin were thrust into 

 a fire, it would be in actual contact with 

 the fire ; but if it be held before a fire, 

 the heat of the fire falls upon it in rays. 



Q. WJiat is the use of the TIN SCREEN or 



REFLECTOR USed in ROASTING ? 



A. The tin reflector throws the heat 



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