Part 43 (1/2)
Q. _What is meant by REFLECTING HEAT?_
A. To reflect heat, is _to throw it back in rays_ from the surface of the reflecting body, towards the place from whence it came.
Q. _What are the BEST REFLECTORS of heat?_
A. All _bright_ surfaces, and _light colours_.
Q. _Are GOOD ABSORBERS of heat GOOD REFLECTORS also?_
A. No; those things _which absorb heat best, reflect_ heat _worst_; and those _which reflect heat worst, absorb_ it _best_.
Q. _Why are those things which ABSORB HEAT unable to REFLECT it?_
A. Because if any thing _sucks in heat_ like a sponge, it cannot _throw it off_ from its surface; and if any thing _throws off heat_ from its surface, it cannot _drink it in_.
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?_
A. The tin reflector _throws the heat of the fire back upon the meat_; and, therefore, a.s.sists the _process of roasting_ and helps _to keep the kitchen cool_.
Q. _How does a tin REFLECTOR tend to keep the KITCHEN COOL?_
A. Because it _confines the heat to the hearth_, and prevents it from being dispersed throughout the kitchen.
Q. _Why does a LAMP GLa.s.s DIMINISH the SMOKE of a LAMP?_