A. Because bright metal _will not absorb heat_ from the hot air, like an _earthen vessel_; in consequence of which, the water is kept cooler. Q. _Why are DINNER-COVERS made of BRIGHT TIN or SILVER?_ A. Light-coloured and highly-polished metal _is a very bad radiator of heat_; and, therefore, bright tin or silver will not allow the heat of the cooked food _to escape through the cover by radiation_. Q. _Why should a MEAT-COVER be very brightly POLISHED?_ A. If the cover be _dull or scratched_ it will _absorb heat from the hot food beneath it_; and (instead of _keeping it hot_) will _make it cold_. Q. _Why should a SILVER MEAT-COVER be PLAIN, and not CHASED?_ A. If the cover be _chased_, it will _absorb the heat of the food_ covered by it; and instead of _keeping it hot_, will _make it cold by absorption_. Q. _What is DEW?_ A. Dew is the _vapour of the air condensed_, by coming in contact with bodies _colder than itself_. Q. _Why is the GROUND sometimes COVERED with DEW?_ A. The _earth is more heated_ by solar rays _than the air_, during the _day_; but at _night_, the earth _parts with more heat_ than the _air_, and becomes (in consequence) 5 or 10 degrees _colder_. Q. _How does the EARTH being COLDER than the AIR account for the deposition of DEW?_ A. As soon as the air _touches the cold earth_, its warm vapour is _chilled_, and _condensed into dew_. Q. _Why is the surface of the GROUND COLDER in a FINE clear NIGHT, than in a CLOUDY one?_ A. On a fine clear star-light night, _heat radiates from the earth freely_, and is lost in open space: but on a _cloudy_ night, the clouds _arrest the process of radiation_. Q. _Why is DEW deposited only on a FINE clear NIGHT?_ A. Because, when the night is _clear_ and _fine_, the _surface of the ground radiates heat most freely_; and (being cooled down by this loss of heat) _chills the vapour of the air into dew_. Q. _Why is there NO DEW on a dull CLOUDY NIGHT?_ A. The clouds _arrest the radiation of heat from the earth_; and (as the heat cannot freely escape) the surface is not sufficiently cooled down _to chill the vapour of the air into dew_. Q. _Why is a CLOUDY NIGHT WARMER than a FINE one?_ A. Because the clouds _prevent the radiation of heat from the earth_; and, therefore, the surface of the earth remains _warmer_ on a dull cloudy night. Q. _Why is DEW most ABUNDANT in situations most EXPOSED?_ A. Because the radiation of heat _is not arrested_ by houses, trees, hedges, or any other thing. Q. _Why is there scarcely any DEW under a shady TREE?_ A. The shady head of the tree both _arrests the radiation of heat from the earth_, and also radiates some of its own heat _towards the earth_; and, therefore, the ground (underneath a tree) _is not sufficiently cooled_ down to chill the vapour of the air into dew. Q. _Why is there never much DEW at the foot of WALLS and HEDGES?_