The progressive farmer. [volume] (Winston, N.C.) 1886-1904, 1896-11-24

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instruments, noting all the elementary
conditions of the air at the bottom Of
the great aerial ocean in which we live
and have III being, and which, by its
variations of heat, cold, sunshine,
clouds and tempest, considerably af
fects, not only the health and happi
ness.of man, but his commercial and
industrial welfare. At 1926 o'clock the
necessary mathematical corrections
had been made the observation reduced
to cipher form, and each had been
fled at the local Office of the telegraph
company. During next thirty Or forty
minutes the observations, with right
Of way over all lines, are speeding to
their destinations, each station contri
| butiDg it's own observations and receiv-
ing in return, by an ingenious system
of telegraph circuits, observations
from ell stations are received at such
centers as Washington, Chicago, New
York and other large cities, and nearly
all cities having a Weather Bureau
station receiving enough reports from
other cities to justify the issuing Of a
daily map. As fast as the reports reach
Washington, they are passed to the
Forecast Division, where a reader
stands in the middle of the room and
tabulates the ciphers into figures and
words of Ineligible sequence.
HIGH AND LOW PRESSURE.
"a force of clerks is engaged in max
ing graphic representations Of the geo
graphical distribution of the diff erent
meteorological elements"
After describing the marking Of the
charts, the lecturer said:
THE f~orecaster knows that high or
low pressure areas drift across the
country from west towards the east at
the rate of about 900 miles daily, or
about 81 miles an hour in winter and
90 miles an hour in summer; that high
pressures are attended by dry, clear,
and cooler weather, and that they are
drawing down by q vertical action of
their centres the cold air from great
dAb4gJA4CS CspONO uLAC SAOuA5 IA OGOE4DE
it to flow away laterally along the sur
face of the earth in all directions from
the centre, and sometimes become so
intense in their vertical motion as to
draw down such vast volumes Of cold
air that We call them cold waves
The fOrecaster knows that cold waves
are not simply immense rivers Of air
that have been chilled bg fowing over
the great snow and ice fields OF the
artic regions, as was once thought.
Low pressures are the reverse of high
pressures. We know that while cur
atmosphere expands upwards to al
altitude probably of fifteen miles, it is
SO elastic and its expansion is go rapid
as it recedes from the earth that half
OF it's masses lie b 9low the three-miles
level. and that our storms and cold
waves are simply great s wirls or eddies
| n the thin lower stratum or probably
not more than five meters in thickness;
that the air above the six. miles level
probably flows serenely eastward in
these attitudes without being disturbed
by our most severe storms.
STORMS R GREAT EDDIES
"O0r storms are great eddies in the
air, carried along by the general cas-
terly movement of the atmosphere in
the middle latitUdes o.. the northern
hemisphere. A storm condition that
extends from Washington 10 Denver,
Is in a horizontal direction, extends but
from four TO five miles upward. The
whole disk Of whirling air, four or five
miles thick and 1 500 miles in diane
ter, is called a cyclone. The tornado
is a revolving mass Of air of only 500
to 1000 yards in diameter, and is
simply an incident of the cyclone.
The cyclone may cause moderate or
high winds through a vast expanse of
territory, while the tornado, with a
rotary motion almost Unreasonable,
always leaves a trail Of death and de
struction in an area infinitesimal in
comparison to the area covered by the
cyclone. The tornado is the most vic
lent of all storms, and is more fire.
quently in the central valleys of the
United States than elsewhere.
81 am satisfied that the number of
these storms is not increasing. The
planting or cutting away of trees, the
drainage Of land surfaces by tiles, the
stringing of thousands of miles of
wire, or the laying Of iron or steel rails
has not materially altered climatic
conditions. As well might one, by the
casting Of a pebble, attempt TO damn