Evening star. [volume] (Washington, D.C.) 1854-1972, 1885-08-15

CYCLONES AND TORNADOES.
What They Are and How They Differ.
c. Morris. in the Philadelphia Ledger.
In view Of the remarkable tornado with
which our city has just been visited and the
somewhat misty ideas generally entertained
concerning storms Of this character, 1t may be
OF interest to present to the readers OF the
Ledger some of the latest conclusions OF science
concerning such storms. The words cyclone
and tornado, for instance, are frequently USED
INTERCHANGEABLE, though they refer TO quite
gists are coming to the conclusion that all
powerful wind storms belong to either the cy,
clone or the tornado class and IL may De wei
to point out their distinctions.
Every wind indicates that in some place the
atmosphere has become thin or rare. The
heavier air surrounding at once flows from oil
sides toward this place, so as to restore the
equilibrium of density. Why the air becomes
rare at special points Is question too large to
be here considered. 1t is mainly due to the
effects of solar heat and radiation. Such rari-
fed spaces may occur in long lines, as along q
of heating and cooling between land and water.
These produce land and sea breezes which have
none Of the eyciOns conditions hut 81 such ,
all. powerful storms are cyclonic.
In a cyclone the rarefaction of air occurs in a
limited space not in a long line, and the move
ment of the surrounding air Is inward from
every side toward this center. We're the earth
standing still. there would be straight lines Of
wind blowing in from every direction to each
rarefed center, and their length and vigOr
would depend on the degree OF rarefaction of
earth on its axis affects the movement of the
winds and defects them from their straight
lines of motion. They stu approach the center,
but in long curves instead OF In q direct line.
The final result is a great circling whirl in the
air, Il huge atmospheric spiral, each line of
which gradually curves in toward The partial
vacuum in the center o. the whirl, and as the
winds approach the center their spec i increases
until. where the rarefaciion is extreme, they
dn0 fIfsfi Drvf fhn
OF the whirl q calm prevails. The opposing air
currents check each others movements or force
each other into an upward flow. This up draught
of air from the center of the wf.irl has its
effect in a violent rain storm. The warm and
moist air. drawn upward rs through great
chimney into the upper atmOSph ere, and its
moisture there rapidly coud nSed by a sudden
chilling, gives rise to rainfall Of unusual viO-
lence.
1t may further be remarked thatthe center
of cyclone is never nxcd. and sometimes
travels with considerat,e capidi'y. The causes
travelling causes. In cCnSeG ueuce, n all places
over which the central lire of .cy clone passes
there is first wind in one dire ction, which
steadily increases in sOlcnce. b.. the CEN
ter Of the cyclone approaches the vino luls and
calm succeeds, attended by violent down.
pour OF rain. Then therc springs Up wind in
the opposite direction. r,pidlv increasing in
violence, while the rain ceases. Finally the
wind slowly lulls as the cyclone moves onward
to new localities.
This change in the direction of the wind Is
necessary from the iact that he wi ndS all curve
inward toward the raIaf1cU &C Ter, and must
therefore move in opposite dirsc lions on oppo-
site sides OF this center. These discoveries In
cyclopic phenomena have Ueeh Of the utmost
Importance to navigation. See an experienced
captain knows from tine Injection OF the wind
in . severe storm just Low 70 steer his ship to
escape its EXTREMIST violence, he makes all
speed from the locality Of the center OF the
cyclone.
A tornado is also n cycionic or spiral wind,
but differs in cause and character from the reg
ular cyclone The latter covers hu DIS or per
haps thousands of miles between IS extreme
limits. The limits OF the tornado q few hun
dred yards. 1t is, in fact, local eay in the air,
and has marked points If similarly to eddies
in the water. Water cudies are due to two
causes. One of these is a meeting Of Two oppo-
site currents The oppcsin. cure ats check each
others onward flow, and cause q spiral, down.
setting Whirl, with water Eacuu;n or empty
space in its center, into which the air must be
strongly sucked. The other cause Of water ed
dies is an under water vacuum. The writer OBJ
after the great storm at one Of the water gates
leading To the turbines at Paramount. The
water was being rapidly sucked from beneath
Into the turbine shoot, producing partial vac
uum, which eXerted pov erfi1 down draught
on the surface waters. In cOI.seQuc nee, eddies
formed e, on the outer edge OF toe disturbance,
yielding roaring sound resembling that Of The
tornado in miniature, and finally disappearing
at the gate, to be succeeded by ever new ones.
The aerial edGics known as tor ADDE'S seem
to be cOunterparts of these water eddies, or
rather of the more extcnsivr eddies known as
whirlpOOlS n tornado IS d maclstrom in the
air, an atmospheric whirlpool directed upward
as water whirlpool is directed downward 1t
has, perhaps, two separate causes. similar to
those just described.-the meeting of opposing
currents and the up draught caused by a par
tial vacuum in the upper air.
This. however. is by no means certain since
the real causes of tOrnadOes are by no means
known. Yet we frequently see minute repre-
in the streets, which travel onward with more
or less rapid1ty, sucking up lust and sticks in
tner course e preciely a. the tornado sucks up
seems some reason to believe that the recent
tornado was due TO the same cause which pro-
of two opposing winds Three tornadoes are
reported from this storm, one in Bucks county
and one in Delaware and Maryland, in addition
to the Philadelphia one. II wind opposition
was their cause, there must have been an ex-
tended lire OF powerful opposed currents.
Another explanation offered for tornadoes IS
that OF a partial vacuum in the upper air caus-
ing vigorous vertical wind. which moves up
ward with a spiral whiri. Whether either Of
these theories is trustworthy remains to be
proved. The analogy with water e6dies would
lead to the idea that the causns Of these ed
dies might be similarly operative in aerial
whirls. But an analogy Is not proof, and
much further observation is needed ere the
question can be settled.
due to tine rapid condensation OF atmospheric
vapor in the line Of the whirlwind. In this con-
neetlon II may be said that photograph of a
differs radically in form from our recent tor
nado, as described by several observers. The
photograph represents a huge bank OF cunulus
clouds. with u snake-like column extending
FROM its lower surface to the earth the
column gradually decreasing in size down ward.
In this II resembles in form the waterspout,
which Is phenomenon of the same character
The philadelphia tornado, on the contrary, is
described as an isolated cloud, at first lying in
horizon tai direction, and finally assuming the
appearance of a vertical cone, with its base
resting OH the earth, its apex upward. In this
respect It's form was opposite to that Of the tor
nado. whirlwind. or wate:spout usually de-
scribed, though it resembled our ordinary dust
whiris. There seems some reason to believe
Tomatoes from yv(
-one, Il revolving, upward push OF the air. due
10 the pressure OF opposing Winds the other, an
upward drag. due 10 u r:.reiactiOn In the upper
atmosphere. However that he. the local and
vertical movement of the tornado distinguishes
IT from the cyclone, with its widely extended
horizontal whirl.
Cooking Peaches.
VARIETY OF WAYS IN WHICH THE PENN.
SCLAR FRUIT MAY BE PREPARED
On the approach of the peach season some
recipes Tor cooking the fruit in various ways
may be of value to housckeepers. The Caterer
August gives the fOliO,viu op,opu otbo.v.