The Indianapolis journal. [volume] (Indianapolis [Ind.]) 1867-1904, 1883-05-24
SIX HUNDRED ToRNApoEs.

fessional papers of the Signal Service, has re-
ported on the character of six hundred tor
nadoes occurring in the United States within
| the present century. Three-fourths of those
reported occurred within ten years. The
report gives the hour, date, direction, length
in miles, width in feet, velocity of progress
| sive motion form of cloud, direction of
whirl-always from right to left in the
Northern NEUTRALITY-SUSPICIOUS. before
and after storm. character of the central
| cloud giving birth to the tornado, as well as
l,the electrical condition of the cloud, and
whether 1t bore rain or hail. The essential
deductions of this very interesting report as
regards time are: that no season or month is
Ql2) in June, and fewest () in January.
TornadoeS are most frequent from noon TO 6
o'clock, the greatest number (52) between 5
an p. M, and but two between and A. NJ.
AS to distribution, that part of the great
basin west of the Mississippi and including
Iowa. Missouri, Kansas and Nebraska, pro-
duces most The great number in this re-
gon has relation to its general physical
| features. We have here a north and south
thermal belt of high contrasts, an immense
range of country without mountains or
bodies of water to oppose the free sweep of
air currents north and south. These lorna
does almost invariably develop in the south
west quadrant of an area of low barometric
pressure In most all cases previous to the
inception OF any given tornado the wind
has been found blowing from southerly
quarter south of the central area Of lowest
| aerial pressure, and also from northerly
quarter north of the same central area of low
pressure, for period of from five days to
two weeks. These conditions may prevail
| in this vast territory until the thermometrc
range on opposite sides-north and south of
tho central area-frequen reaches fifty
degrees This great disturbance of atmos-
pheric equilibrium due to the contact of
| the southeastern return trade winds from the
| equatorial regions with the northwestern
winds from polar regions, results in an enor-
| nous tornado center in the States mention
ed. III this center arise the May and
June cyclones which have become
| source of constant terror to the
| people Of this region. There are two
| other 'areas of frequency in the United
STATESMEN York and Georgia. The first is
due to similar contact of the warm wi:,d-
LAT tba lab
cold northerly winds of the Canadas To
this center are due the New York and New
England tornadoes, as /, the Wallingford,
Conn.,, tornado OF Aug. 0, 1873. in
which the contrasts of temperature ranged
from thirty to sixty degrees The Allan
| tic or Georgian, center is due, of
| course, to the formation OF similar thermal
belt OF high contrasts, occasioned by the
warm moist Gulf winds sweeping over the
heated plains of Georgia and Alabama, and
then coming in contact with the cool winds
OF the Appalachian mountain system. Here
are born the great wind-storms and cyclones
that sweep northwestward along the ALLIE
ghenies and wreak destruction on the cities
and shipping OF the Atlantic coast of the
United States.
In brief we have in the United States three
well-defined cyclone centers; that is, three
areas of low barometric pressure, where, in
the recovery of atmospheric balance the
great opposing air currents. northerly and
southerly, sweep against each other aud pro-
duce the whirling eddies of air known as
cyclones, tornadoes or hurricanes. They are
all cyclic; all revolve opposite to the hands
of watch. All move eastward, and at a rate
Of twelve to sixty miles an hour, the average
being twenty-eght. The cyclic velocity
within the storm cloud is varously
estimated at from one to eight hun
bred miles an hour. Torradoes have
four motions; progressive; whirlng;
lateral, darting from one side of their paths
to the other, north and south; lastly, rising
and falling. tits these bounding tornadocs"
that sometimes as once in Iowa. suck up the
waters of pond or prairie Slough" and
deluge farm yard. sweeping away stock and
fences. They also explain the rain of river
fish and frogs, known to haye occurred on
dry lands. In width they vary from forty
to 10000 feet with an average of 1000; in
length from two to 200 miles, with an aver
age of twenty eight. Four hundred are re-
ported as violent thunder storms; fifty with
out electrical phenomena; in others the
cloud is described as of the color of red-hot
IRON or as II filled with balls of fire. They
occupy from ten seconds to fifteen minutes
in passing given point with
mean in fifty cases of six