Q. _Why is a TUMBLER of cold WATER made quite DULL with mist, when brought into a room FULL of PEOPLE?_ A. Because the _hot vapour of the room_ (coming in contact with the cold tumbler) _is condensed upon it_; and changes its invisible and gaseous form for that of a _thick mist_. Q. _Why is a GLASS made quite DULL, by laying a HOT HAND upon it?_ A. The _insensible perspiration_ of the hot hand is _condensed_ upon the cold glass, and thus made perceptible. Q. _Why are WINE-GLASSES made quite DULL when they are brought into a room FULL of COMPANY?_ A. The _hot vapour of the room_ (coming in contact with the cold wine-glasses) _is condensed_ upon them, and covers them with vapour like dew. Q. _Why does this misty appearance GO OFF after a little time?_ A. Because the glass becomes of the _same temperature_ as the _air of the room_, and will no longer _chill the vapour_ which touches it, and _condense it into mist_. Q. _Why is a WINE-GLASS (brought out of a CELLAR into the AIR) covered with a thick MIST in summer-time?_ A. The vapour of the hot air is _condensed_ by the cold glass, and covers it as a thick mist. Q. _Why does BREATHING on a GLASS make it quite DULL?_ A. Because the hot breath is _condensed_ by the cold glass; and, therefore, covers it with a thick mist. Q. _Why do WALLS stand thick with WET in a sudden THAW?_ A. The walls (being thick) cannot _change their temperature so fast_ as the thin air can; and, therefore, they _retain their cold_ after the thaw has set in. Q. _How does RETAINING their COLD account for their being so WET?_ A. As the vapour of the warm air _touches the cold wall_, it is _chilled_ and _condensed into water_, which _sticks to the wall_, and sometimes trickles down in little streams. Q. _Why does a thick WELL-BUILT HOUSE contract more DAMP of this kind, than an ORDINARY one?_ A. Because the walls are much _thicker_; and (if the frost has penetrated _far into the bricks_) it takes a long time to reduce them to the _same temperature as the air_. Q. _Why are BANISTERS, &c. DAMP after a THAW?_ A. The wooden banister (being made of some very close-grained, varnished wood) cannot _change its temperature so fast_ as the air; and, therefore, _remains cold_ some time after the thaw has set in. Q. _How does THIS account for the BANISTERS being DAMP?_ A. The vapour of the warm air (_coming in contact with the cold banister_) is _chilled_, and condensed into _water upon it_. Q. _Why is our BREATH VISIBLE in WINTER and NOT in SUMMER?_ A. In _winter_ the coldness of the air condenses our breath into _visible vapour_; but in _summer_ the air is _not cold enough_ to condense it into visible vapour. Q. _Why are our HAIR and the BRIM of our HAT often covered with little drops of pearly DEW in winter-time?_ A. The breath (issuing from our mouth and nose) _is condensed into drops_, as it comes in contact with our cold hair or hat; and (being condensed) hangs there in little dew-drops.