Year: 1872

OF the storm, and rise of the barometer


the front and rear.


Inls central line Of minimum pressure is


generally OF great length from North to


south, and moves side-ioremost toward the
sea.


Ihls line is sometimes nearly straight,
out generally curved, and most frequently


with It's convex side toward the East.


The velocity Of this line is such that it
travels from the Mississippi to the Con
nectlcut river in about twenty-four hours,
aud from the Connecticut to St. Johns,
NewloundlInd, 10 nearly the same time, or
| about thlrty-six miles an hour
When the barometer falls suddenly in the
western part OF New England, it rises a.
the same time in the valley OF the Missis
sippi, and also at s. Johns, Newfound
Iaud


In great storms the wind for several
hundred miles on both sides of the line OF
minimum pressure blows toward that line
directly or obiquely.


The force of the wind is in proportion
to the suddenness and greatness of the de-
preston of the barometer.


In all great and sudden depressions Of
the barometer there is much RAIN or snow !;
and in all sudden great rains or snow there
IS great depression Of the barometer near
the center OF the storm, and rise beyond
its borders.


Many storms are Of great and unknown
length from North to S uth, reaching
beyond our observers on the Gulf Of Mexico
and on the Northern lakes, while their
East and West diameter is comparatively
small. The storms therefore more side-
foremost


Most storms commence in the "far
West" beyond our most Western observ-
ers, but some commence in the United
States.


When a storm commences in the United
States the line OF minimum pressure does
not come from the far Vest but com
mence' with the storm, and travels with 1t
tow ard the Eastward.


There IS generally lull Of wind at the
line Of minimum pressure. and sometimes
u calm.


When this line Of minimum pressure
passes an observer toward the East the
wind generally soon changes to the West,
aud the barometer begins to rise.


There Is generally but little wind near
the line OF maximum pressure; and on
each side Of that line the winds are Irregu-
lar, but tend outward from that line.


Tne fluctuations Of the barometer are
generally greater IN the Northern and the
Western parts Of the United States.


la the Northern parts Of the United
States the wind genera II, IN great storms
sets IN from the North OF EIst aud tcrmln-
4tes from the North OF West: and m the
Southern parts the wind generally sets in
from the South OF East and terminates from
the South OF West


Daring the passage Of storms the wind
generally charges from the Eastward to
the Westward by the S,uth, especially in
the Southern parts OF the UIted States.


Tne Northern part Of the storm general. |
y travels more rapidly toward the East
han the Southern part


During the high barometer Of the day
preceding the storm 1t Is generally clear .
4, mild IL temperature, especially Il very I.
old


The temperature generally falls sudden
Y On the passage Of the center Of great
Storms and sometimes, when storm Is
n the middle Of the United States, the
owest temperature Of the month wlI be
u the West on the same day that the
highest temperature Is in the East.


The first OF the principles upon which
he Signal Corps proceeds Is, toat the in
ariab.e course Of ar currents is such as
will equalIz5 the atmospheric pressure up
~ the earth surface, and that whenever
inequalities exist the winds are set in mo-
ion, the air thus finding its leyel-just as
water or any other visible fluid does