, 1886-06-15
CAUSES OF CYCLONES.
CONTRASTS OF TEMPERATURE AND
BAROMETRICAL PRESSURE.

The Chance n Tornado Would Have Mt a
City Like Chicago-The Danger Too Re
mote to Worry About-A Favorite Field
-Neccssary Conditions.
The recent destructive cyclone vista
tons have renewed interest in these
mysterious and terrible phenomena Every
inhabitant of the section within range has
probably pondered over the possibilities of
personal experience. The nearest point
to Chicago recently reached by the wild
winds has been Racine, and the surmise is
not ~infrequenlly INDUCED as to what
would have been the effect II the cratic
visitor had taken a more southerly point
on the lake shore for n landing and
tackled Chicago. No instance is yet on
record of the whirling wind-wave meeting
with an obstacle sufficient to break it up
and dissipate it's deadly intensity into
harmless zephyrs; yet meteorologists
declare that 1t Is only n question OF the
degree of resistance opposed to Its appar-
emily all destroying course. The absence
Of record evidence OF this kind is &C
counted for by the fact that negative re-
suits are not reported, while the destruc-
ton caused is always a matter of world
wide notoriety.
The atmospheric conditions preceding
cyclones or tornadoes are similar. They
consist, in the main, Of strong contrasts of
temperature and barometrical pressure.
Warm and cold currents meet on the con-
fines of a "high' and slow" area I pres
sure and the result is a cyclone or tor
nado, the character being largely deter
mined 10y the degree of contrast in the OPP
posing conditions. The velocity with
which the storm travels Is an important
element in distinguishing between the
two classes, cyclones sweeping their
tracks with swift destruction, while the
force Of a tornado is expended to a great
degree in its rotary movement.
CYCLONE IN A CITY.
Sergt. Buell., the observer in charge of
the signal office in this city, was asked
what chance a cyclone would have at a
city like Chicago.
"No cyclone or tornado could get into
Chicago, except by the lake front, and
then 1t would Don be demoralized by its
contact with solid structures" he said.
"The reason we never hear of a cyclone
devastating a big city is that it gets de-
moralized after doing n little damage in
the suburbs. There is protecting iniu-
ence about all large communities; that is,
the volume of heated and rareled air that
il ascending all the time, which acts as a
cushion. The high winds that prevail oc-
casionally in this vicinity never get inside
the city without losing two-thirds OF their
velocity.
Toledo was visited by n tornado a few
years ago, but beyond tearing up some
wooden sidewalks and carrying off u
frame building in the suburbs it did no
damage. No substantial brick or stone
buildings were damaged, except by having
tin roofs or spires destroyed.
Anything that breaks the continuity Of
the revolutions will demoralize either a
cyclone or tornado just like a w~ater-spout,"
added Sergt. Buell.. Hence, contact
with a solid structure would be fatal to
the continuance of a cyclone, or would at
least break the force of the pendant portion
which sweeps the ground and does all the
damage"
SCARCELY n DANGER
Surprising a cyclone should strike this
city from the lake front at a point where
a wide thoroughfare opens on the waterS"
well, II it did, and II 1t happened to be
travelling upon the line followed by the
street in question, it would damage the
fronts of the buildings, carry away signs
and all movables lying about until it
should meet a solid block OF building, and
then 1t would be broken up, Its violence
Wouhh NC uihiihisucu uisO ny tHt iIlCblOu
of its outer edges against the sides OF the
building. But the nance of such a thing
happening are SO remote that 1t Is scarcely
worth %'supposing' anything about it,"
There Is IA record in Sergt. Finley's Re
port on the Character of Six Hundred Tor
nadoes," OF a visitation to Cook and Jeffer-
son counties of u very violent tornado on
May %, 1855, when four persons were
killed. In this list Illinois takes second
place as n favorite field for %tornadoes, hay
ing a record Of ffty-four, Kansas heading
the list with sixty-two. There is reason to
believe that the large number of storms
reported from certain localities has some
relation to the general physical features of
the region. One Of the necessary coEdi-
tions precedent to the formation of a belt
OF high contrasts is the existence of a wide
range of country offering no obstacle, like
mountain ranges or large bodies of water,
TO the free sweep OF air currents either
north or south. This condition is most
completely consummated in the vast ex-
tent Of country, largely unbroken prairie.
reaching from the gulf, east Of the Missis-
sippi, n%orthward to the British posses
sions.-Chicago Mail.
Testimony of IA Professional Mesmerist.
1t is a well known fact among physicians
that people are occasionally born with
l.. So IA nj