The Republican. [volume] (Oakland, Md.) 1877-current, 1891-01-30
CYCLONES AND ToRNAooes.
rhe Time and Conditions sIost Favorabls
to Them.

rhe Time and Conditions sIost Favorabls
to Them.
Lieutenant John p. Finley, of the
United States Signal Service, has writ
zen a very interesting article on the
origin and development of cyclones and
ornadoes-the former being the typical
general storm and the latter the typical
ocal storm. He shows that while cy-
,lones may develop within the United
states, they usually enter this country
rom adjacent regions. The places of
sntry are the North Pacific coast (Ore-
ron and Washington, North Dakota
Ind the Gulf coast. From each'of these
quarters the cyclones approach with pc
;uliar characteristics Those entering
;he country over North Dakota are most
frequently accompanied by tornadoes.
TO understand the relation of the
tornado to the cyclone we must con-
slider the cyclonic disturbances as di-
gided into quadrants by two lines at
right angles, one running north and
south and the other east and west. The
northwest quadrant is distinguished by
| y
cloud formations, especially in the
southern portion, together with pre-
cipitation. The southeast quadrant con-
tains the maximum of heat and moist
ure; it is the region of all classes OF
local storms, especially of the tornado
The southwest quadrant is marked by
clearing weather and diminished hui
| 4hn ~
minimum of heat and moisture, with
brisk, cold winds. The southeast quad
rant being the recipient of heat al
and moisture, generates the cyclon
and the most violent disturbance of I'll
equilibrium being in this quadrant, and
within a limited area, the centripetal
force becomes much greater, and the
formation of the tornado ensucs.
The questions which naturally occur
are: What places are best adapted to
the development of tornadoes, and what
is the time when conditions are most
favorable to them? Lieutenant Finley
points out that tornadoes are found in
regions where warm, moist air begins
to flow underneath "a colder and dryer
upper stratum that comes from another
direction. This condition is followed
shortly by an Inversion of the air in the
upper and lower strata, the first visible
effect of the coming storm being the
appearance in the west and northwest
of "a heavy, portentous bank of clouds
followed suddenly by n violent com
motion on the face OF the dense BLACK
mass, ard by the rushing of adjacent
clouds toward the center of the dis
turbance, especially from the southeast
east and northeast; as TO time the sum
mer season is most favorable for lorna
does, when the interior of the cOntinen
is warming and the air of the lowe,
strata is drawn from lower latitudes fa
up in the northern portions of the coun
try on the eastern side of the Rocky
Mountains, the isothemal curve bein;
detected very decidedly toward thu
north.
, Lieutenant Finlcy's summary of tn
, results of his Investigations seem t.
cover every thing that can be learned OF
the subject. Briefly, the most import
ant of them are as follows: Tornado
generally accompany q low prcssur
area; the progressive motion of the tor
nado is to the northeast and the lorna
, do, with scarcely an exception, occur
in the afternoon, just after the hotties
part of the day. The tornado season il
cludes March, April, May, June, July
August and September, the months G
greatest frequence being April, May
June and July. From careful invet
tigation there is every reason to believ
that these storms were us frequent an
! violent 200 years ago rs they are now
; and there appears to be no cause fo
any unusual change in their annuf
: frequency for a like period to come.
As regards protection in case of
9 tornado, Lieutenant Finley can, info
y tunately, say little, except that tn
. south side of the tornado's path is tn
dangerous portion and the north side
the safe one. If the clouds be movin
& to the northeast, then the line of escaI
. is to the northwest; if to the east, the
9 to the north. TO one who stands facin
the advancing cloud in the direct line {
4 its approach, the safe side is always
the right. No structure that rises aboy
, the earth, however built, can who'll
, resist the violence of the tornado, ant
therefore, no building is safe, either {
t property or as refuge to protect lif
From a business point of view, Their
fore, as affecting the questions of lii
Z and property, the tornado must be COZ
4 sidered as natural agency for destru
: ton, to be carefully watched and col
tinually provided against.-Philade lphi
Record.
I CARRIAGE PEOPLE.