A Guide To The Scientific Knowledge Of Things Familiar Part 32

Q. _The proverb says, "A RAINBOW in the MORNING is the shepherd's WARNING:" why is it so?_

A. A rainbow can only be formed _when the clouds_ (containing or dropping rain) _are opposite the sun_: a _morning_ rainbow, therefore, is _always in the west_, and indicates that bad weather is _on the road to us_.

Q. _Why does a RAINBOW in the WEST indicate that BAD WEATHER is on the road to us?_

A. Because our heavy rains are usually _brought by west or south-west winds_; and, therefore, clouds which reflect the colour of the rainbow _in the west_, are coming up _with the wind_, bringing rain with them.

Q. _The proverb says, "A RAINBOW at NIGHT, is the shepherd's DELIGHT;"

why is it so?_

A. As a rainbow is always _opposite to the sun_, therefore a rainbow at _night_ is in the _east_, and indicates that bad weather is _leaving us_.

Q. _Why does a RAINBOW in the EAST indicate that bad weather is LEAVING us?_

A. As _west_ and _south-west_ winds bring _rain_, if the clouds have been driven _from the west to the east_, they have pa.s.sed _over us_, and are going _away from us_.

Q. _What is meant by an AURORA BOREA'LIS, or northern light?_

A. A _luminous white cloud_ in the _north of the sky_ at night-time.

Sometimes streaks of blue, purple, and red,--and sometimes flashes of light, are seen also.

In our island this phenomenon generally rises from a dark cloud (running from the north to the east and west) elevated about 10 or 20 degrees above the horizon: above this dark bed of clouds the luminous white light appears.

Q. _What is the CAUSE of the AURORA BOREALIS, or northern light?_

A. _Electricity_ in the clouds.

Q. _Why is the AURORA BOREALIS generally a WHITE light?_

A. Because the electric fluid pa.s.ses through air _extremely rarefied_: and whenever electric fluid pa.s.ses through _air much rarefied_, it always produces a _white light_.

Q. _Why are there sometimes DIFFERENT COLOURS in the aurora borealis, such as yellow, red, and purple?_

A. Because the electric fluid pa.s.ses through _air of different densities_. The most _rarefied air_ produces a _white light_; the most _dry air, red_; and the most _damp_ produces _yellow_ streaks.

Q. _Does the AURORA BOREALIS forbode fine weather or WET?_

A. When its _corruscations are very bright_, it is generally followed by stormy moist unsettled weather.

Q. _Why does a HAZE round the SUN indicate RAIN?_

A. Because the _haze_ is caused by _very fine rain falling in the upper regions of the air_; when this is the case, a _rain_ of 5 _or_ 6 _hours continuance_, may be expected.

Q. _Why is a HALO round the MOON a sure indication of RAIN?_

A. Because the halo is caused by _fine rain falling in the upper regions of the air_. The _larger_ the halo the _nearer the rain-clouds_, and the sooner may rain be expected.

Q. _Why does a BLACK MIST bring WET weather?_

A. The mist is _black_, because it is _overshadowed by dense clouds_ or ma.s.ses of vapour; and, therefore, it forebodes wet.

Q. _Why does a WHITE MIST indicate FINE weather?_

A. The mist is _white_, because _no clouds blacken it with their shadow_; and (as the sky is cloudless) _fine weather_ may be expected.

Q. _Why do we FEEL almost SUFFOCATED in a hot cloudy night?_

A. Because the heat of the earth (being unable to escape into the upper region of the air, in consequence of the clouds) _floats_, like a sea of heat, _on the surface of the earth_.

Q. _Why do we feel more SPRIGHTLY in a clear bright night?_

A. Because the heat of the earth can readily escape into the upper regions of the air, and is not confined and _pent-in by thick clouds_.

Q. _Why do we FEEL DEPRESSED in SPIRITS on a WET murky DAY?_

A. 1st--Because when the air is laden with vapour, _it has less oxygen_.

2ndly--The air being lighter than usual, _does not balance the air in our body_: and

3rdly--Moist air has a tendency to relax the nervous system.

Q. _What is meant by the "air balancing the air" in our body?_

A. The human body is filled with air of the same density as that around: if, therefore, we ascend into _purer air_, or descend into _denser air_, the balance is destroyed, and _we feel oppressed and suffocated_.

Q. _Why do we feel OPPRESSED and SUFFOCATED if the air around is not of the SAME DENSITY as that in our body?_

A. If the air around be more dense, it will _squeeze our body in_ by its weight: if it be _less_ dense, the air in our body will _blow us out_.