The Iola register. [volume] (Iola, Allen County, Kansas) 1875-1902, 1896-02-21
U. S. WEATHER BUREAU.
Some Interesting aud Instructive Obsel
vatiOns About the Objects it Seeks
and the Work it Does
BY CLARENCE J. NORTON.
PART TX.

fairly reliable forecasts of general
weather conditions, from day to day.
He ought, at least, to be able to per-
cieve the indications of an approach
ing storm, or "low," though he may
not locate the area of precipitation.
Coming events cast their shadows
before" is an old saying that is espec-
tally applicable to the weather. At
any rate it is true that nearly all not
able or marked changes are fore
Swallowed in various ways. A good
barometer, or polymeter, will give
an infsllible indication of an approach
ing cyclone or "low," though the
barometer does not tell you whether
or not it will bring precipitation in
your locality. To determine the ques-
ton as to probability of rain, some
other points are to be considered;
particularly, the amount of vapor or
humidity in the air and the direction
of the wind.
But even without a barometer an
intelligent observer can quite readily
note the coming of "low," and other
indications of storm movement. All
nature is full of barometers and near
ly every animate creature is sensitive
to marked changes in air pressure.
The air is lighter when a low pre-
walls, and this removal of pressure
sometimes causes rise of water in
streams, springs and wells. Smoke,
vapor, and other gases, which are
lighter than air in its normal condit-
ion, show a tendehy to fall when the
barometer pressure is low, At such
times birds are more sluggish In their
movements and have less power to
make lofty flights.
The total air pressure, at its normal
stage, upon the body of an average
sized man IL about fourteen tons, or
nearly fifteen pounds to each square
inch. We are not conscious of this
external pressure because there is air
of equal density In the tissues and
other portions of the body. The out
side pressure is counterbalanced by
inside braces. But sudden change
in the outer pressure causes an expan-
sion of the air within the tissues, CIV
ing rise to a peculiar or unpleasant
sensations, such as are experienced
by rhuematic subjects or extremely
nervous people. \ fall of two inches
in the murcery of a barometer is equiv
alent to the removal of one ton of
pressure from the cutter surface Of the
body. So every one feels the effect
and notes the difference between low
and high pressure. Some of the lower
animals, possessed of acute sense, are
warned by instinct of impending
changes of weather. They are especi-
ally sensitive to change in the pres
sure and humidity.
Nearly all cyclones are preceded
by warm waves and followed by
collier ones. In fact, low barometer
and high temperature are usually
quite closely associated. So period
OF extreme heat may be regarded,
generally, as precursor of a storm,
especially if the wind comes from a
quarter where moisture is generated.
/ The wind is also a good indication.
When the wind blows freshly and
persistently from a southerly point,
the storm center is at the west or
northwest. Place your back to the
wind, then the lowest pressure will
be at your left hand and the highest
at your right. By this simple rule
you may at any time locate the storm
center and determine whether it is
coming or receding. Remember the
general course is always from west to
east and when the wind veers from
south to southwest and then west,
the bulk of the storm is passed north
ward; when the wind backs round to
east and then TO northeast the storm
center is passing across the valley
south of your point of observation.
Humidity is essential TO the produc-
ton of rain, and when the air is near
the point of saturation its effects can
be felt and noted. We are much more
sensitive to heat when the air Is
heavily laden with vapOr, because of
lessened evaporation of Precipitation.
And at such times, preceding a sum-
mer rain, the animals show the effect
Of the change in humidity, pressure
and temperature, and by CAREFUL OBJ
servatiou we may quite redily deter
mine when these conditions exist.
When the air is filed with vapOr the
corn feder can be handled without
breaking, and corn stalks should not
be cut: the walls Of cellars, or of stone
houses. are more than usually damp,
pitchers of cold water "sweat" pro-
fusely. ropes and other kinds Of cor
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