A. Because the air in the upper regions is _more rare_ than the _air in their bodies_; and (till the _equilibrium is restored_) great pain is felt in all the more sensitive parts of the body. Q. _Why do PERSONS who DESCEND in DIVING-BELLS FEEL PAIN in their eyes, ears and chest?_ A. Because the air in the sea is _more dense_ than the air in their bodies; and (till the _equilibrium is restored_) great pain is felt in all the more sensitive parts of the body. Q. _Why does the SEA HEAVE and SIGH just PREVIOUS to a STORM?_ A. The density of the air (just previous to a storm) is _very suddenly diminished_, but the air in the sea is _not so quickly affected_; therefore the sea heaves and sighs _in its effort to restore an equilibrium_. Q. _Why is the AIR so universally STILL just PREVIOUS to a TEMPEST?_ A. Because the air is _suddenly and very greatly rarefied_; and (as the _density of the air is diminished_) its power _to transmit sound is diminished also_. Q. _How do you_ KNOW _that_ RAREFIED _air_ CANNOT TRANSMIT SOUND _so well as dense air?_ A. Because the _sound of a bell_ (in the receiver of an air-pump) _cannot be heard at all_, after the air has been partially exhausted; and a pistol _fired on a high mountain_ would not sound louder than a _common cracker_. Q. _Why do we FEEL BRACED and LIGHT-HEARTED on a FINE spring or FROSTY morning?_ A. 1st--Because there is _more oxygen_ in the air on a fine frosty morning, than there is on a wet day: and 2ndly--A brisk and frosty air has a tendency to _brace_ the nervous system. Q. _Why do DOGS and CATS (confined to a room) feel LAZY and DROWSY at the approach of rain?_ A. 1st--Because the air does not contain _its full proportion of oxygen_: and 2ndly--Because the damp _relaxes their nervous system_, and makes them drowsy. Q. _Why do HORSES neigh, CATTLE low, SHEEP bleat, and ASSES bray, at the approach of rain?_ A. 1st--As the air does not contain its full proportion of _oxygen_, they feel a _difficulty in breathing_: and 2ndly--As damp _relaxes their nerves_, they feel languid and uneasy. Q. _Why do CANDLES and FIRES burn with a BLUER FLAME in WET weather?_ A. As the air contains _less oxygen_ in wet weather, the _heat of fire is less intense_: and the flame is blue, _because the fuel is not thoroughly consumed_. Q. _Why do HILLS, &c. appear LARGER in WET weather?_ A. Because (when the air is _laden with vapour_) the rays of light are _more dispersed_, and produce a larger reflection; objects, therefore, seen at a distance, _appear larger_. Q. _Why do TREES, &c. in WET weather appear FURTHER OFF than they really are?_ A. Because the fog or mist _diminishes the light_ reflected from the object; and as the object becomes _more dim_, it seems to be _further off_. Q. _Why does the SUN seem LARGER when he SETS and RISES, than he does at noon?_