The Portland daily press., 1871-09-22

In the fourth meteorological report by Prot.
j. F. Epsy, OF Washington, d. c., we ind the
loiioWlnS Instructive gene. alizations:
1.-The ram and snow stOrps, and even the
moderate rams and SHOWS, travel from the
west towards the east in the UDied States
during the months of November, December.
January, February and March, which are the
only moLths to which these generallzatfons ap-
ply.
2-The storms are accompanied with a de-
preston OF the barometer near the central 'ipe
Of the storm, and rise of the barometer in the
front and rear.
3-This central line OF minimum pressure is
generally OF great length from north to south,
and moves side foremost towards the east.
4-Ihis line is sometimes nearly straight but
generally curved, and most frequently with its
convex side toward the east.
5-The velocity of thts line is such that it
travels nom the Mississippi to the Connecticut
rive In twenty-four hours, and from the Con-
necticut to ST. JObn's, Newfoundland in near
y the same, or about thirty six miles an hour,
6-When the barometer falls suddenly in the
western part OF New England, it rises at the
same time in the valley OF the Mississippi, and
also at st. Johns, Newfoundland.
TN great storms the wind for several hun
dred mics on both sides of the line OF mini
mum pressure blows toward that line directly
or obhquely.
8 Tue force of this wind is in proportion to
the snddenness and greatness Of the depres-
SION ot the barometer.
Gin all great and sudden depressions of the
barometer there is much rain or snow; and in
all sudden great rains or SHOWS there is great
depre SCION Of the barometer next the centre of
the storm, and rise beyond its borders
III Many storms are of great and unknown
length from north to south, reaching beyond
our observation on the Gull of Mexico and on
the Northern lakes, while their east and west
diameter is comparatively small These storms
therefore move side foremost
n-Most storms commence in the "far west"
beyond our western observers, but some COM
mence in the Uuited States.
12-Wher storm commences in the United
States the line of minimum pressure does not
come from the star west," but commences
with the storm, and travels with it toward the
eastward.
13- There is generally lull of wind at the
line of minimum pressure, and sometimes
calm.
| 14-When this line of minimum pressure
passes an observer toward the east, the wind
generally soon changes to the west and the
| barometer begins to rise.
15-Tnere is generally but little wind Bear
| the line OF the maximum pressure, and on
| each side of that line the winds are irregular,
but tend outward from that line.
| 16-The fluctuations of the barometer are
| generally greater in the eastern than in the
| morally greater in the northern than in the
| southern part OF the United States.
| 10-ln the northern part of the United States
the WHO generally sets in from the north Of
east, aud terminates f, ON the porth OF west.
19-ln the southern parts of the United
| States the wind generally sets in from the
| south of east and terminates from the south of
west.
| 20-During the passage of storms the wind
| generally changes from the eastward to the
| westward by south, especially id the southern
| parts OF the United States
N-The northern part of the storm general
| ly travels more rapidly toward the east than
| the southern part.
| 22-During the high barometer on the day
| preceding the storm it is generally clear and
| mild in temperature, especially if very cold
| weather preceded.
23-The temperature generally falls sudden
| y on the passage of the centre of great storms,
| so that sometimes, " hen storm is in the mid
| ture of the month will be in the west on the
same day that the highest temperature is in
| the east.
Some of the storms, it is true, are contained
for time within the bounds of my observers,
| not exhibit itself in line of great length, ex-
to region near the centre Of the storm, and
| travels with that centre toward the eastward.
From these experiments it may be safely in
ferred, contrary to the general belief of scien-
tific men, that vapor permeats the air from a
| high to a low dew point with extreme slow
ness it, ineeed, it permeates it at all: and in
meteorology, it will hereafter be known that
| vapOr rises into the Iegions where clouds are
forced only by being carried up bv ascending
currents of air containing It, Scientific Amer
| icun,