Richmond dispatch. [volume] (Richmond, Va.) 1884-1903, 1885-10-11
HOW ToRNADoES FORM.
MYSTERIES OF THE CLOUD.

Miles nm Hour.
A Washington special says: Lieu
tenant John p. Finley, OF the signal
corps, has been studying the phenomena
of tornadoes for the past eight years:
Tornadoes are now so well understood
that it is believed that trustworthy |
warning can soon be sent out to the
localities threatened. In fact, expert
mental predictions have been made Tor
year, with good result.
According to Lieutenant Finley, tor
nadoes have distinctly marked charac-
teristics and are by no means to be
COMPOUNDED with hurricanes, "blIz-
cards." cyclones, or northeasters.
Their tracks are never more than few
hundred yards wide. Their rotary
motion, which is greatest towards the
centre, sometimes reaches the enor-
nous rate Of 1000 miles an hour,
while their forward movement, always
from southwest to northwest, ordinarily
does not exceed forty or fifty miles.
They are usually unsccompanied yelec-
trical disturbances and are believed to
be uninauenced by electrical conditions,
though violent thUnder-storms some
times follow them a few miles away.
THE HOME OF THE TORNADO.
There is a distinct and curious rela-
tionship between the tornado and the
general storm-centre, which is always
apparent in their uniform relative posi-
tons, the tornado always occurring
enthusiastically from the centre of low
barometic pressure and at distance OF
from one to six hundred miles. The
shape of the general storm-centre, tho
direction in which its lowest barometer
lies, and the appearance ofthe upperand
lower clouds enteras minor elements into
the problem out Of which the weather
experts hope to work complete sys-
tenn of tornado warnings. The visits Of
the tornado are commonly between the
hours Of and & o'clock in the after
noon. Its home is an area VIII ch in
cludes the whole Of Iowa, all Of Mis-
souri, except the southeastern corner.
the northwestern corner Of Arkansas,
the northeastern part of the Indian Ter
ritOry. Eastern Kansas, Eastern Ne
braska, Southern Minnesota, Southern
Wisconsin, and Western Illinois.
Here its season extends from April to
August inclusive. 1t is also frequent
visitor to two other regions. These
are, first, a strip along the Gulf and
South Atlantic coasts. which takes in
the central portions of Alabama, G,or-
gia. and South Carolina. with termni
in Mississippi and North Carolina, over
which its deyaStations are confined to
the months Of January, February, and
March. The second includes portion
Of Southern and Central Ohio. urge
portion u Pennsylvania, small area
in Mary land, a strip across New York,
and n corner Of each of Massachusetts,
and Connecticut. where it is in season
only during August and September.
HOW THE TORNADO FORMS.
hecondtions which are favorable to
the creation OF Tomatoes are present
when a cool. dry current Of air mee.s
a warm, moist current, bringing wide
extremes both Of temperature and hu-
midity into close proximity. The cool,
dry currents come from the north,
but such as flow over the great lakes
pick up in their course both
moisture and heat, and their de-
structive forces are thus neutralized.
Those blowing from the far north
west, down over the dry plains of Mani
toba and Dakota, carry something Of
their Arctic characteristics far South,
and if in their course they meet one Of
the heat and yapor-aden breezes
coming up from the Gulf the war of
the elements begins at The point of
contact. The storm always has its
birth in the upper air, its first visible
manifestation being the ominous fun
nel-shaped cloud, whose pendant trunk
is in form not unlike that of an ele-
plant. Within it the furies are con-
fined. and when and where its point
touches the earth the path Of destruc-
ton begins. When the isotherm Of the
morning signal-map shows the adyanc-
ing columns of air, with their wide con-
trasts Of temperature, in proximity;
when the general storm-centre is in that
relative position which seems necessary
to the exercise of its mysterious inhu-
ence when the pressure is low toward
the east. disclosing vacuum into which
the detected currents may advance
without obstructiOn-whe all these
conditions combine it should become
but simple problem for the experts to
determine with reasonable probability
from the wind yelOcitics whether the
threatening line Of contact will have adj
yanced to or beyond the tornado's ac-
customed haunts by the time of day
when the powers of mischief shall be
loosed.
TIE UNKNOWN QUANTITIES.
The chief remaining unknown quaint
ties in the problem consist Of data Of
time and place, a great store Of which
is already in hand and only awaits dl-
gestion and tabulation, while 800 spc-
cial tornado observers are gathering adj
ditional facts respecting current storms
and from all available sources the
stories Of long past Tomatoes,
known to the earlier settlers as wind
falls. Thus. while host of interesting
scientific questions respecting the origin
of tornadoes. the laws which, govern
them, and their relationship to other
meteorological phenomena remain to be
answered. the more practical questions
as to when and where they are likely to
appear seem to be advancing rapidly
toward solution.
The interests which are subject to
disaster from tornadocs are alive to the
importance OF the work in progress.
Intending purchasers of farms apply to
the Signal Office for information re-
specting the liability of their selected
locality to disaster. To such are sent
the records Of the past as far as
they are known. Whenever Lieu
tenant Finley travels in pursuit
of his studies farmers and villagers
press for information. To these he
says that nothing raised by the hand of
man above the surface Of the earth can
withstand the shock of the tornado.