The Washington herald., 1909-03-28

tween you and the ceiling. You viii now
see that the spiral OF the cyclone or
low" Is moving with the hands OF the
watch when you look toward the cirec-
ton Of vertical movement. In other
words. all air swirls Ike all water
swirls IN the basin. revolve with a right
hand motion in the direction OF the YER
tical Increment The cyclone Is simply
your water swirl moving upward instead
OF downward Mathematicians say that
the water swirl is due 10 the fact that
when the water OF the basin first begins
10 move toward the hollow over the
opened waste pipe, some inequality in
the inward currents causes one or more
Of them 70 be showed a little 20 one side
OF the center. This side-tracking starts
the swirl, which grows more and more
energetic. The water swirl always rc-
tates IN the same direction For killing
time. nothing IL more efi>ient than Try
ing 70 get a basin swirl with a left
hand rotation. Why II is always right
hand We 90 not know The rotation OF
cyclones and anti-cyclones Is right
handed in the northern hemisphere but
* is left-handed IN the southern hemis-
phere, supposedly because OF the influ-
ence or the rotation OF the earth The
basin swirl which we have described Is
always right-handed in the northern
hemisphere. II Is our intention 10 learn
from the state Department which one, II
any. Of our southern hernispherss consu-
lates possesses a circular wEsh-basin with
q central outlet. and 20 apply 10 that con-
sulste for the missing testimony ss 20 the
direction Of the water swirl In southern
attitudes. The demonstrated existence Of
a left-handed water swirl rotation there
might profoundly alter the course OF
meteorological hypothesis-making-
The approach OF a high" usually
means clearing and cooler weather. This
result Is due 20 the fact that the outpour-
ing currents from the high center are de-
Iived from the upper regions OF the air
The descending cooler and drier current
disperses clouds. and in this region the
resulting clearing wind IS very apt 20
come from the northwest. hence colder.
also fOr the additional reason that Il
brings IN some relatively cold surface
air from colder regions
Causes OF Bad Weather.
Bad weather in our region IS due. bar
ring 5erhaps thunder storms. to the
moisture and temperature conditions OF
the winds which blow inward over our
surface 20 the center OF low pressure.
These winds have an increasing velocity
as they approach the low center, but az
a considerable distance from that cen
ter, sometimes as much as zoe or 500
miles. they lost their velocity. ard in the
center itself there Is practically q calm
The temperature about q low center Is
lowest on the north and west sides-this
is what we should expect from the fact
that the winds on those sides comes from
relatively colder regions which do nOt
n H-
south OF the low" We md the greatest
warmth and the greatest amount Of
moisture. and hence the greatest proper
lion of rain. This Is because IL the pass
age Of low centeEs across the continent
the easterly and southerly winds which
feed the low center generally come from
the moist and warm ocean 10 the south
and east or from the Gulf region and the
moisture-supplying river valleys Of the
interior Of the country. For the same
reason the westerly side. or the south
westerly siie. OF a high-pressure AREA Is
warmer than It's other sections and car
ries more or less cloudiness, and perhaps
ran. These variations in the weather con-
ditiOns surrounding q high" or a Tow"
you can easily work out for yourself by
drawing two spiT2ls or opposing direc-
tions and here you win ind IL practically
the hands Of a watch and the low spiral
against
Remember that winds from the east and
the south are usually warm and moist,
while those from the north and west are
colder and drier; with these things in
mind you can determine the weather con
dirons in the various portions OF the two
systems with considerable exactness. You
viii see, II you draw q vertical line
through The center OF each Of the weather
spirals. that this line divides the wind di-
rections into two fairly distinct groups,
which mean different sets Of weather con-
dlti0ns. In a cyclone, or low" this near
y north and south Inc marks Of the
easterly and southerly winds on the
front Of the storm from the northerly 20
westerly winds that prevail on the rear
OF the storm The wind directions in the
case OF a high pressure center are just
the reverse Of this The winds In front
of the north and south line are nOrtherIy
20 westerly: behind this line. easterly and
southeriy. II you draw TWO diagrams
for these spirals. with their dividing north
and south lines. and then put one dia-
gram. upside down, upon the other. you