Yorkville enquirer. [volume] (Yorkville, S.C.) 1855-2006, 1907-03-29
WORK OF THE WINDS.
Like Summer Thunderstorms They
All Serve q Purpose.


Like Summer Thunderstorms They
All Serve q Purpose.
1t is a matter Of common observa-
tion that when the window Of warm
room is opened on a still winter night
the cold air from without rushes into
the room. Nearer the ceiling the
warmer air is forced out Of the
window, thus completing general at
scale. These currents Of air. which
might properly be called wind" would
not occur II the air within doors was
not warmer and consequently lighter
than the air without.
The range in temperature between
the Equator and the North Pole
amounts in winter to considerably
more than 100 deg. Fahrenheit, and in
summer the contrast is also great.
Moreover. in summer the continents are
warmer than the oceans, but in winter
the reverse is true. Three examples
will serve to illustrate how such con-
trasts affect the winds Of the world.
At the Equator the temperature av-
erages about 80 degrees throughout the
year. Consequently the lower air flows
in from regions of high pressure on
each side, forming what is known as
the trades. These winds cover nearly
one-half Of the earth's surface and
blow with much steadiness the year
round.
The monsoons, or seasonal Winds"
Of India and the Indian ocean are the
most interesting Of their class. In
summer the cooler ocean air pushes In
toward the land, while the warmer air
over the continents rises to consid-
erable height and then flows out to
sea, forming systematic circulation
between ocean and continent. In win
ter the ocean is warmer than the con-
tinent and the winds reverse their d.
rection.
The "land and sea breezes" occur
with much regularity near large bodies
Of water in some parts of the world.
The ocean is cooler than the land dur
ing the day and warmer at night.
causing on small scale daily inter-
change Of air similar to that caused
by the monsoons.
A clear knowledge Of the term "air
pressure" Is very helpful in studying
the causes Of wind. Air, like a stone,
presses against the ground; in other
words, 1t has weight, amounting to no
less than 2,117 pounds upon every
square foot Of the earth's surface at
sea level, but unlike stone, the at
mosphere Is elastic to high degree
and also presses in all other directions.
On account of this elasticity Of the
air, certain forces which arise from
differences in temperature and the
earth's rotation cause 1t to become
dense or heavy in some regions and
rare or light in other regions.
1t is the effort Of the atmosphere to
overcome these pressure differences
and resume state Of equal density
that causes the winds to blow.
The column OF mercury in barom-
eter tube is always just balancing
column Of air of the same diameter
reaching from the barometer to the top
of the atmosphere. II the air Is dense
the mercury win Of course stand high
In the tube, and to express this condi-
ton we use the term high pressure"
But IL the air is rare the mercury VIII
stand low in the tube. and we then
use the term low pressure"
Technically the low-pressure areas
are called cyclones" and the high
pressure areas "anti-cyclones." They
are frequently 1000 or more miles In
diameter. The little storms Of great
destructive force so often called ICY
clones" are really ''tornadoes."
The higher the pressure in any par
ticular region relative to some other
region the greater will be the velocity
of the wind. The winds blow much
faster In winter than in summer be-
cause the greater contrasts Of temper
ature cause more decided differences
in pressure.
Observations demonstrate, however,
that the wind never blows in straight
lines, because all bodies Of air when
in motion ore acted upon by a law OF
nature called the DETECTING force Of
the earth's rotation" This force turns
all wind to the right of its course In
the northern hemisphere and to the
left in the southern.
Thus, II a wind in our hemisphere
starts north 1t is soon turned slowly
toward the northeast, or II 1t starts
west II will soon turn toward the
northwest. When 1t is remembered
that at the Equator the earth is rotat-
ing at the enormous velocity Of LoS6
miles an hour one will not wonder that
such DETECTING force could exist. All
areas Of high and low pressure, from
whatever cause, therefore, become
whirling masses Of air, and a little
thought will show that they must turn
In opposite directions. In the north
ern hemisphere the low areas, or
Lows" as they are designated on the
weather map always rotate In q direc-
ton contrary to the movement Of the
hands of watch.
The winds are among the greatest
blessings provided by an all-Wise
Providence. Just as the squall OF
thunderstorm brings relief from the
sitting heat of summer day, so all
winds serve some special purpose In
making the eartn a desirable habita-
ton for mankind.-Youth's Compan-
ion.
Worn Away BY Handling.