A. No; _air is a very bad conductor_, and is heated (like water) _by convection_. Q. _How is a ROOM WARMED by a STOVE?_ A. The air _nearest the fire_ is made hot _first_; _the cold air descends_, is heated also, and rises in turn; and this goes on, _till all the air of the room is warmed_. Q. _Why are FIRES placed on the FLOOR of a room, and not towards the CEILING?_ A. As heated air always _ascends_, if the fire were not _near the floor_, the lower part of the air (which we want to be the warmest) would never be benefited by the fire at all. Q. _If you take a POKER out of the fire, and hold the HOT END DOWNWARDS, why is the HANDLE so intensely HOT?_ A. Because the hot end of the poker _heats the air around it_, and this hot air (in its ascent) _scorches the poker_, and the _hand which holds it_. Q. _How should a RED-HOT POKER be carried so as not to BURN our fingers?_ A. With the hot end _upwards_; because then the air (heated by the poker) _would not pass over our hand_ to scorch it. Q. _Why is a POKER (resting on the FENDER) COLD; but if it leans against the STOVE, intensely warm?_ A. The poker is an _excellent conductor_; while, therefore, it rests against the hot stove, the heat of the stove is _conducted into the poker_; but when it _rests on the fender_, it does not come in _contact with the hot stove_. Q. _Why does it feel so COLD, when it rests on the FENDER?_ A. Not being so warm as our hand, it _imbibes the heat from it_ with such _rapidity_, that our loss of heat is _palpable_, and produces the sensation of coldness. Q. _Why are FLUES (which are carried through a church or room) always BLACKENED with BLACK LEAD?_ A. In order that the heat of the flue _may be more readily diffused_ throughout the room. Black lead radiates heat more freely than any other known substance. Q. _Why do country people touch the thick end of an EGG with their TONGUE, to know if it be STALE or not?_ A. The thick end of an egg always contains _a little air_ (between the shell and the white); but, when the egg is stale, _the white shrinks_, and the air expands. Q. _How can the TONGUE tell from this, whether the egg be STALE or FRESH laid?_ A. As air is a _very bad conductor_, if the egg be _stale_, it will feel much _warmer to the tongue_, than if it be new-laid. Q. _Why will the big end of an egg feel WARMER to the tongue, because it contains more AIR?_ A. As air is a _bad conductor_, it will draw off the heat of the tongue _very slowly_, and, therefore, _appear warm_; but when there is only a _very little air in the egg_ (as the _white_ is a pretty good conductor), the heat of the tongue will be _more rapidly_ drawn off, and the egg _appear colder_. Q. _Why is the large END of an EGG CRACKED, when put into a saucepan to boil?_ A. _To let the air out_; if the large end were _not cracked_, the air (expanded by the heat) _would enter the white of the egg_, and give it an _offensive taste_. PART II. AIR.