Los Angeles herald., 1908-03-22

local equipment is an instrument known
as a tele-thermograph, which electric
ally records in the office each varia-
ton in temperature as communicated
from register located on the roof of
The building. A nephoscope, used In
the observation of clouds, while not in
general use, is to be found in some
offices.
On the office walls the visitor will
find numerous charts descriptive of
rainfall, seasonal and annual sunshine,
highest and lowest pressure and tenn
rerature and other phenomena, while
another set of charts graphically de-
ricts the progress of storm area from
the Pacific coast across the country
until it passes to sea off the New
England coast. These charts are very
useful in explaining the movement of
storms and enhance the educational
value of the office exhibit. This is a
prominent feature of the work of the
local office. many classes from the city
educational institutions. and those of
the surrounding cities and towns. Wis
iting the office in the course of the
school year.
Visitors Always Are Welcome
Nor are the instruments and charts
the only things of interest to be found
in the average weather bureau oft1ce.
Beautiful photographs of clouds, kites
and snow crystals are on file, While
the we'll stocked library of meteorologi-
cal and Chronological information is
at all times at the disposal of the stu
dent, tourist, homeseeker and business
man. Visitors are always welcome at
the weather bureau after 10 a. M, and
all callers are given as much time as
the work of the Office will permit.
That portion of weather bureau work
that comes most to the attention OF the
public is the daily forecasts, and it
may be interesting to know how the
reports from all over the country, up
on which these forecasts are based,
are taken and gathered at the different
offices.
All meteorological observations are
taken at the same moment of time,
that is 18th meridian time, or that
in use at Washington, d. G. When
the observer in Washington Is taking
his observation at a. M, the OBJ
server at Chicago is taking his read
ings at a. M, while in Denver the
instruments are being read at a. m.
On the Pacific coast the observers are
less fortunate in the matter of early
rising than their eastern brothers, for
they must take their observations at
8 in the morning. These readings when
made and entered on forms provided
for the purpose are enciphered on a
special telegraph blank, and then filed
in the telegraph office, where, through
a system of telegraphic circuits, the
message is sent all over the country,
and in comparatively short time after
filing the. report the offices in the east
know just what kind of weather we
are having on the Pacific slope, while
we In turn are informed of the actual
state of the weather to the east of US.
AS fast as these reports are received
they are entered on large charts, or
outline maps of the United States,
data of pressure, temperature, wind,
weather, clouds and rainfall being en-
tered, sometimes together on one chart,
and sometimes on separate charts,
How the Work Is Done
Lines are then drawn through places
of equal pressure and for every tenth
of an inch, and these lines are tench-
known as 'isobars." Lines
called "isotherms" are also drawn, con-
Meeting places of equal temperature.
These are drawn for every ten de-
grees and are not as regular as the
isobars, following a more or less tr-
regular course as they pass from coast
to coast. The places, or more properly
speaking the areas, of highest pressure
are marked "high' and the depressions
or areas of low barometric pressure
are designated as lows" These lat
ter are the storm centers or cyclones,
while the high areas are the great
of air, or the anti-cyclones.
These areas, both high and low, obey
well known physical laws, and move
across the country from west to east,
some in regular, we'll beaten tracks,
others in abnormal and irregular
paths. 1t is from a knowledge of the
of these vast areas that the
deductions relative to the coming
weather are made. Well known local
signs are sometimes taken into ac-
count, for the appearance of the sky,
the kinds and movements of clouds,
halos, and other phenomena often give
valuable indications of coming changes
in the weather. The general circula
tion of the atmosphere from west to
east on this continent renders it some
what difficult to determine accurately
the extent and movement of storm
areas on the Pacific slope, as we have
no field of observation over the ocean
to the west, whence comes our supply
of weather, good and bad With the
further development of wireless teleg-
raphy it may be possible at some fu-
ture time to get reports from some
distance at sea, and these doubtless
will prove a great aid in forecasting
the weather in this section Already
some of our army transports and coast
wise vessels are equipped with wire
less outfits, and reports are now being
received from the ocean at some of
the larger stations in California, Ore
gon and Washington.
Distributing information
The daily weather map to be found
posted in public places. is but repro
duction of the forecast chart above re-
ferred to, with the addition Of the fore
casts for the district in which the sta
ton is located, and brief resume of
the weather conditions over the
The field of observation on this con-
tinent is large, and besides the reports
fl ON all sections of the United States,
advices are received rela-
tive to the weather at all Canadian
stations, Alaska, Hawaii, the Azores,
West Indies Mexico and some of the
South American countries, while re-
ports from the British isles, Germany,
France, Portugal and Ireland are re-
ceived once a day at the central office
Of the bureau in Washington. All these
form one vast picture of
the weather covering the greater por-
ton of the globe and go to show the
great development made in the science
x.14., t..