The New Orleans daily Democrat., 1878-06-07
THE LAWS OF STORMS,
ORIGIN OF HURRICANES, CYCLONES
AND TORNADOEs CLEARLY
ELUCTDATED.

HOW STORMS ORIGINATE.


formation of the storm centre and of the
storm. 1t Is well known that black objects
become hotter, when exposed to the sun, thar
white ones The consequence Is that The
former have more heat to communicate to the
air, or to anything else, than have the latter
SO. In like manner, sandy deserts and barrer
spots absorb. and therefore radiate or give
out, more heat than grassy or wooded plains
The air over desert is, consequently, more
likely to become superheated than that over
the surrounding territory. In some desert
or barren spot, or tract more favorable fOI
the production Of heat than its surroundings
the air frequently becomes Overheated. The
natural consequence is that it expands
and, being then lighter than the
surrounding air. it rises. Whereupon
the heavier surrounding air presses
inwards from all sides to supply its place.
as the water in bucket does when you
take q cupful up out of it. The air thus flow
ing In becomes heated in turn and rises too
and then more air from all around but fur
ther off, is partly drawn and partly forced in
wards, and thus the disturbance increases in
extent. While thus expanding it also in
creases in violence and thus an extensive
storm is formed. The air moving inwards
from the north Is of course a north wind, but
gradually the rotation of the earth affects it
and dn. these latttudesl it becomes, a
northeast wind. The direction of the
flow OF air in other parts of the
storm is similarly changed by the same
cause, and the result Is that strong wind is
produced over q vast tract of country, in
which the movement of the air is spirally in
ward in great circular sweeps towards a com
mon centre, where the barometer is lowest
and where the heated air rises until it reaches
an elevation above the earth where the cold
cbills 1t and thereby turns the vapOr it has
brought up into clouds AS the mighty Oper-
alton goes forward more air continues to
ascend with more vapOr, forming more clouds,
which are driven OutwardS in all directions
from the storm centre. Very soon the clouds
become oyerweighted and then rain falls, and
the Tain-area extends and moves with the
storm. / omitted to say, as I ran along, that
the currents Of air flowing inwards from all
directions become more and more Tari-
lied and more and more electrified as
they move, for friction always produces eleC-
tTicity. 1t also becomes more and more
heated, and the consequence Is that its vapOr
is preeipitated in the form. of clouds, which
either in vast, woolIy, piled up masses or in
the form OF g. lying, ragged "scud, as the
storm intensities, drives inward with the
rushing wind. Thus the upper clouds will be
observed moving outward from the storm
centre and the lower clouds inward, as a
general rule, with or nearly with the wind
The clouds, as they form or drive along In the
tempest, become more and more charged with
electricity, and soon the red flashes and
nimble coruscatiOns of the lightning and the
crashing and rolling thunder startle the in
ferior creation and awaken the attention of
men:
See where 1t smokes along the sounding
Blown all aslant. driving. dashing rain:
Peal upon PEP, rCdoubling all around,
shakes Y again and faster 10 the ground
Rryv PVyfH nnyu CFIapp q d., ,,In
Swift beyond thought the lightnings dash
away"
Such storms are called cyclones In the At
lantic and often in the United States; hurr-
canes In the West Indies and typhOOns else
where. They are, as we have said, whr-
winds on large scale; but the "wbirl'' does
not continue on to the centre, very fortunately,
because the ascending column of heated air at
the centre Is 50 very large-Often couple of
hundred Of miles in diameter But the fol-
lowing, from leading meteorological will
give q better idea OF the whole storm with
reference to its size:
"Storms are sometimes nearly circular, but
generally very much elongated, their length
being two or three times their breadth; and
in the United States the longest axis of the
oval is uniformly turned in north and south
direction. Sometimes the barometer sinks |
below its mean height over an area extending
three thousand miles in north and south |
direction and one thousand miles east and |
west. At the centre the barometer is lowest |
Beyond the area of low barometer, the ba- |
rometer rises above its mean height"
Consequently the storm is great atmOs- |
pheric depression lit might be said), sur |
rounded by an atmospheric elevation. These |
depressiOns are attended, as a rule, by rain or
snow, and perhaps, thunder and lightning, |
and sometimes hail, and move over the earth
lin these latitudes) from southwest to north |
east, in q manner exactly similar to the move |
mentS Of the waves and depressiOns in the |
ocean. Sometimes the regularity of q storm !
lie interfered with by another which, In ex- |
panding, approaches it. Frequently high
hill divides storm in two causing tOrnadOes, |
as we shall see hereafter; sometimes, also. |
other causes, which, cannot be treated here
for want of space, will separate storm as, |
for instance, the cascade of descending air |
from the upper regions of the atmosphere |
which comes down to the earth along the |
parallel Of 80 deg. north latitude. To this Is !
due many OF the tOrnadOes Qf not all of them)
that occur in Georgia.
Turning from the consideration of such |
facts, which at present can only arouse curl |
osity without satisfying it, we come to the
velocity of storms. Storms, as | have already !
indicated, have two VelOCitieS, like the little |
whirlwinds Of which we have spoken, one ro-
tary and spirally inward, and the other a |
of translation which carries the !
storm as a whole from one locality to another |
AS far as is known these two motions have no |
with one another. The movement
OF translation Is variable. Sometimes the |
storm makes no progress for several days, |
but continues to pour and blow at the same
places from the same direction for several
days. The Alps of Switzerland have been |
known K! hold storm in one place for
two weeks. In the United States a !
storm has been known, within the last /
three years, to rage in Texas and in the gulf |
for five or six days, for an unknown reason, |
and then to advance nOrtheastward as usual. |
They move thus from place to place at the |
rate of ten to fifty miles an hour usually. |
West Indian cyclones have about the SAME |
of translation. But the whirling
motion, spirally inward, is independent Of |
that and averages from twenty to seventy !
five miles per hour. In West Indian cyclones |
1t often runs up to 12O and last January at |
Mount Washington, n. H., it blew at the rate |
Of $50 miles per hour for probably an hour or
two. This is the highest recorded velocity
Sometimes on account of the operation |
Of a number of causes an extensive |
storm contracts, and, as it contracts, |
It Judgments fearful1y in Violence" as |
Professor Loomis says: Judging by the
reports already in land it must be admitted |
that they are meagre) it seems to me that the
cyclone at Richmond, Mo, is contract |
Dcr IGnn nTNTnCR nf Q