Evening star. [volume] (Washington, D.C.) 1854-1972, 1911-05-14

whether it has q bearing on the growth
of crops" says Mr.. Abbott in discussing
astrophysical observatory. 1T is found
that it is not necessary to have the
whole output Of the sun as received Gus
tomarily, but that fractional part would
be sufficient for the proper growth OF
crops. The question. then. is what part
is best for certain vegetation? Is it the
green rays. or the blue, or the invisible?
Or are some parts even harmful? FOR
such experiments as this our measure
ments of the amount of radiation Of the
different colors are very desirable. ana
even highly necessary. DR.. Lyman j.
Briggs Of that department Is experiment.
ing on certain apparatus to be put IN
the hands Of farmers for the purpose OF
measuring the amount OF radiation ac-
tually received at the earth's surface
This, taken in conjunction with our meas
urements Of the suns radiation. should
be Of great value for agricultural pur-
poses"
conceived the idea that perhaps 1t was
a mistake to assume, as astronomers al
ways had done, that the amount or the
suns radiation was invariably the same:
This suspicion was created In his nina
when he noted that a decrease OF about
10 per cent in the suns radiation. which
occurred at that time. was followed py
a general fall of several degrees IN the
normal temperature of the United states
and Europe. He concluded it would be
we'll to make tests which would prove
or disprove the idea.
To do this ii would be necessary to
measure the amount of radiation received
at the earth's surface, figure the amount
of radiation lost In the atmosphere and
by adding the results thus obtained de-
termine the amount of the radiation be-
fore II entered the earth's- atmosphere.
II these tests were made simultaneously
in Washington and at Mount Wilson. and
the estimates of the loss In the
air proved the same at both points, 1t
would be known there was no error in
making the computation Then IL the
measurements Of the suns radiation be-
fore 1t entered the atmosphere showed a
similar variation at both points on sue
cessive days, 1t would tend to bear out
Mr.. Abbot's theory that the fluctuations
were in the sun itself.
Accordingly Mr.. Abbot went to Mount
Wilson. where the Smithsonian built a
permanent station, In 1906. 1905 and 1908
while one Of his assistants remained in
Washington to make simultaneous meas
urements. The results at the two sta
lions checked and substantiated, but
tncy were not accepted as COHCiuSiVo.
Instead it was decided to establish q third
station on Mount Whitney, where the
elevation is three miles. as compared with
one mile at Mount Wilson and sea level
at Washington.
In 1909. therefore, Mr.. Abbot went to
Mount Whitney, but unfavorable weather
interfered with the observations and 1t
was necessary to go again in 1910.
my expedition" says Mr. Abbot In de-
scribing the difficulties encountered In
getting his instruments up the mountain.
which is three miles high. lacked the
picturesqueness and eclat that dis
tinguished Langley's many years previ-
Gus, with its private car. it's guard OF
cavalry, and a budding astronomer OF the
first rank, the renowned Keller. as as
sistant. However. I rode from Mojave
to Lone Pine, about $50 miles. In an auto
mobile, trying all the while desperately
to keep my pryhelfometer from being
broken, and was consequently bounced
myself once to the roof of the automo-
bile and barely escaped q broken nose.
My treasured pryheliometer afterward
rolled down tho Mount Whitney trial
twice with the pack mule. and the second