The watchman and southron. [volume] (Sumter, S.C.) 1881-1930, 1903-09-09
OUR AUGUST TEMPERATURE.
The Difference in Location of the Their
mometers in Cities and the Country
Explained.

During the past month of August
the thermometer daily reading in
Sumter was invariably from 2 to 4
degrees higher than was reported from
Columbia, and in the minds of some
persons arose the idea that either the
instruments at this point were at fault
or that the reports were misrep.esent-
ed at Columbia in the interests of that
place, while others recognized the
faclt that the Columbia instruments
were placed on the top of very high
building, which should give a cooler
temperature than near the ground.
The voluntary observer in Sumter ad-
dressed letter to Section Director j.
". Bauer at Columbia upon this sub
ject and the following is a portion of
his reply which explains itself:
Columbia, Sept. 8, 1908. 1.
Mr.. F. Prescott-Bullock, Sumter, S. G.
Dear sir: Your recent letter asking
why thermometers are exposed on high
buildings in cities and near the ground
by voluntary observers, has the atten-
tion of this Office, and would have
been answered sooner, but for a rush
of work incident TO the first few days
of the month. The question Of a
proper exposure for thermometers is
not simple affair, especially in cities,
for the ideal exposure is near the
ground, over sod, and free from all
radiated or reflected neat, and also
in close proximity to the Office, and
other outdoor instruments. A little
thought will show you that in cities,
where most of the regular Weather
Bureau stations are located, these con-
ditions are impossible, so the best ex-
posure for all instruments is selected,
which for the. rain-gauge is as near
the center as possible Of large fat
roof higher than surrounding build
ings, if possible, and for the wind
vane and thermometer site free from
artificial wind reflections, or wind
currents, which also means the roof of
tall building, and for the thermome-
ter location as near to the others as
possible. Ordinarily the difference in
temperature is one degree for each 800
feet in elevation. Now as few stations
are more than fifty feet above ground,
it means only fraction Of a degree
cooler, scarcely enough to be notice
able in many years record.
Now, the object at regular Weather
Bureau stations is to get tempera-
ture at each station that is comparable
with every other, i. e. that is obtained
under the same conditions. This is
more for the purpose of weather fore
casting than for Genealogical pur-
poses, although it answers for the latter
also, while the reading from voluntary
stations are entirely for Chronological
purpoes and for studying the influence
of the weather on crops, for both Of
which it is best to have the tempera
ture near the ground. Following out
the ideas suggested in the last para
graph you will see that there is no in
tention to misrepresent the tempera-
ture in either the cities where regular
stations are located or at voluntary
stations, but that each serves its par
ticular purpose best under the present
system of exposures.
I trust that this somewhat lengthy,
but not exhaustive letter will serve to
answer the leading question of your
communication, or at least will set
the trend of your thoughts in the right
direction for an answer, | am,
Very kindly yours,
j. ". Bauer, Section Director.