Q. Why are reflectors always made of light-coloured and highly polished metal?
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. What is the use of the tin screen or reflector used in roasting?