Part 39 (1/2)
Q. _Why is the TIN FOOT-WARMER covered with FLANNEL?_
A. 1st--To prevent the perspiration of the foot from taking off the _polish_ of the tin:
2ndly--Flannel is a _very bad conductor_; and, therefore, helps to keep the tin hot _longer_: and
3rdly--If the feet were _not protected_, the conducting surface of the tin _would feel painfully hot_.
Q. _What harm would it be if the POLISH of the tin were injured by the perspiration of our feet?_
A. _Polished_ tin throws off its heat _very slowly_; but dull, scratched, painted, or dirty tin, _throws off its heat very quickly_: if, therefore, the tin foot-warmer were to _lose its polish_, it would _get cold in a much shorter time_.
Q. _Why are FURNACES and stoves (where much HEAT is required) built of porous BRICK?_
A. As bricks are bad conductors, they _prevent the escape of heat_: and are, therefore, employed where great heat is required.
Q. _Why are FURNACE DOORS, &c. frequently COVERED with a paste of CLAY and SAND?_
A. Because this paste is a _very bad conductor of heat_; and, therefore, prevents the _escape of heat from the furnace_.
Q. _If a stove be placed in the MIDDLE of a room, should it be made of bricks or IRON?_
A. A stove in the _middle of a room_ should be made of _iron_; because iron is an _excellent conductor_, and rapidly communicates its heat to the air around.
Q. _Why does the Bible say, that G.o.d ”giveth SNOW like WOOL?”_
A. As _snow is a very bad conductor of heat_, it protects vegetables and seeds from the frost and cold.
Q. _How does the non-conducting power of SNOW PROTECT VEGETABLES from the FROST and cold?_
A. As snow is a bad conductor, it prevents the _heat_ of the earth _from being drawn off_ by the cold air which rests upon it.
Q. _Why are WOOLLENS and FURS used in COLD weather for CLOTHING?_
A. Because they are _very bad conductors_ of heat; and, therefore, _prevent the warmth of the body from being drawn off_ by the cold air.
Q. _Do not woollens and furs actually IMPART heat to the body?_
A. No; they merely _prevent the heat of the body from escaping_.
Q. _Where would the heat ESCAPE to, if the body were NOT wrapped in wool or fur?_