Mower County transcript. [volume] (Lansing, Minn.) 1868-1915, 1882-08-09
CONCERNING CYCLONES.

and tornadoes resemble cyclones in many
of their characteristics, but in sew
eral particulars they differ widely and
radically. The range of the largest tor
nado is only fraction of that of the
smallest cyclone; and while cyclones ap-
pear at all hours, tornadoes and whirl-
winds are generally confined to the hours
violent manifestations of the whirlwind,
are known in nearly all climates, but cy-
clones have their origin in the tropics.
Whirlwinds and tornadoes occur where
the air is unusually moist or warm for
the time, and where temperature and
humidity consequently diminish with
height at an abnormally rapid rate; but
cyclones appear under conditions imply
ing unequal densities of the air at equal
heights, due to inequalities in the geo.
graphical distribution of temperature or
humidity. In other words, whirlwinds
and tornadoes owe their origin to verti-
cal disturbance of the atmospheric equil
ibrium, while cyclones are due to hori-
zontal disturbance; the former are short.
lived, but the latter rage for days and
travel far.
WATERsPOUTs, WHIRLwINDs AND TOR
NADOEs
are essentially the same, differing only in
dimensions, intensity or the degree in
which the moisture is condensed into visi-
BILE vapor. The main features of whirl-
winds are best observed in waterspouts,
because of the more or less complete con-
densation of moisture into visible cloud
Waterspouts are generally formed during
period of great heat, and are most fire.
quent in the calm regions between the
tropics. The observer first notices dark
cloud from which there is projection in
the shape of an inverted cone. As this
projection becomes larger and extends
downward, the water Immediately under
meath is heaped up agitated violently.
BY this time the whirling motion which
began in the clouds has reached the
water, and is probably continuous
throughout, although part of the whirl-
ing column has not yet been made visible
by the condensation of moisture into cloud:
The extension of the projection from the
clouds is not due, according, to Professor
Ferrel. to the descent of vapor, but to the
visible condensation of the vapor of the
spirally ascending air currents arising
accelerated rate of the gyrations, the con-
densation being similar to that of the
cloud seen in exhausting an air-pump.
As the whirling of the upper part of
the waterspout become more intense the
rarefaction of the air within is increased
and the condensation into clouds con-
tinues downward until the entire column
is visible. Then there is roaring noise
like thai of great waterfall, but within
moderate distance around the water
spout, calm usually prevails. As soon
as the rapidity of the rotary motion is
lessened the condensation of vapor is
diminished and the column gradually
breaks up and disappears, the cloud
sometimes discharging itself in rain.
THE WATER UNDER THE WATERFRONT
is agitated because the atmospheric pres
sure beneath the column is less than the
pressure around it. This fact is illustrated
in another way when q tornado on
land passes over closed building. In
many such cases the walls and roof of the
house have been thrown out violently,
showing that the pressure outside was
suddenly and largely diminished and the
air within as suddenly expanded. In
this way the tornado. works great part
of its destruction to life and property.
The progressive motion Of tornadoes and |
whirlwinds varies greatly, the rate being.
probably, that of the general movement |
of the atmosphere OF which they are a
part. Tomatoes sometimes occur at
Comparatively low elevations without |
reaching down to the surface of the earth,
and in such cases they rage with violence |
on the hill-tops. leaving intervening
valleys unframed. During the onward
movement tornadoes sometimes rise above |
the surface for short time and then
descend again. It is not improbable that |
the wind sometimes reaches q force in |
tornadoes exceeding what is ever reached !
in cyclones, but it does not blow for so |
long time or travel so far as in the eye
lone. Some meteorologists. assuming
that tornadoes were formerly confined
almost exclusively to the Immediate |
neighborhood of the tropics, point to
every tornado that occurs in the West
and Northwest as an evidence that the |
climate of the United States lis under |
going important notifications, the char
acter and extent of which can only be
dimly guessed at" It is more probable,
tornadoes is due to the fact that as the |
country becomes more thickly settled
fewer storms pass by unnoticed. In these
days of telegraphs and railroads all dis
astrous storms are promptly reported,
but when the country was thinly |
settled, storms were seldom heard Of far |
from the places where they occurred.
THE Waseca Radical says the Rey. Mr.:
Tibbetts, presiding elder Of the United |
nh, rn0 $<avs a fyeA1 n,