The daily telegram. [volume] (Clarksburg, W. Va.) 1901-1926, 1907-05-16
WHY THE WIND BLOWS
4 Study Of the Circulation Of the
Worlds Atmosphere.
that MOVE THE AIR.
Contrasts In Temperature, High and
Low Pressure and . Law Of Nature
Called The psssetins Force Of the
Earth's Rotation.

Earth's Rotation.
It Is q ratter Of common observa-
tion that V zen the window Of warm
room Is opened on a stiIl winter night
the cold NJ. from without PUSHES into
the room. Nearer the ceiling the
warmer air Is forced out Of the vim
dow, thus completing a general atnos-
pherie circulation on a miniature scale.
These currents Of air, which might
properly be called wind. would not
occur IL 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 degrees F., and in summer the
contrast is also great. Moreover. in
GUNNER the continents are warmer
than the oceans, but in winter the re-
verse Is true. Three examples viii
serve to illustrate how such contrasts
AFFECT the Winds of the world.
at the equator the temperature aver
ages about so degrees throughout The.
year. Consequently the lower air flows
In from regions Of high pressure on
each side, forming what are known as
the trades. These winds cover nearly
one-half Of the earth's surface and
blow with much stcadiness the year
round
The monsoons, or season.. 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 consld-
cradle height and then flows out 10
sea, forming systematic circulation
between ocean and continent III win
ter the ocean is warmer than the con-
tinent, and the winds reverse their
direction. .-...s-@r.4
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 warmef at night. caus-
ing on a small scale a. daily Inter
change OF air similar to that. caused
by the monsoons.
A clear knowledge Of the term ''alr
pressure" is very helpful in studying
the causes OF wind. Air. like q stone,
presses against the ground-in other
words. 1t has weight, amounting 10 no
less than 2.117 pounds upon every
square foot OF the earth's surface at
sea leyel-but, unlike a stone, the at.
mosphere is elastic TO a high degree
and also presses IN ailsother disenfionss,
On account of this elasticity OF the
air, certain forces which arise from
differences In temperature aud tho
eartlfs rotation cause 1t to become
dense or heavy In some regions and
rare or light In other regions.
II Is the e1tort OF the atmosphere 10
overcome these pressure differences
and resume state Of equal density
that causes the winds to blow.
The column Of mercury in barome-
ter tube is always just balancing
column of afr of the same Diameter.
reaching from the barometer TO iiie
top of the atmosphere. If the air Is
dense the mercury viii Of course stand
high in the tube, and to express this,
condition we use the tern, high
pressure" but il the air is rare The
mercury viii stand low in the Tube.
and we then use the term slow pres
sure."
Over the United States. Canada and
other parts of the world the pressure
Is ascertained each day at numerous
stations The barometer readings, O.
pressed in inches Of mercury. are tele-.
graphed to central point and there
charted on a map. The exact Feslons:
where the pressure is high or flow
may then be seen at a glance. ct has
been learned from such observations
that these areas are constantly showing
eastward at an average rate OF about
600 miles per day.
Technically the low pressure arens.
are called cyclones and the high
pressure areas -'anticyclones." They
are frequently 1000 or more miles In
diameter. The little storms OF great
destructive force so often called c..
clones are really tornadoes.
The higher the pressure in any par.
ticuIar 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 tempera-
ture 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 are acted upon by 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 IL a wind in our hemisphere
starts north It IS soon turned slowly
toward the northeast, or IL It starts
west It win soon turn toward the
northwest When it Is remembered
that at the equator the earth IS rotat-
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