Rock Island Argus. (Rock Island, Ill.) 1893-1920, 1911-05-06
RADIATION VARIES
DR.. Abbot, Astronomer, Hopes
to Prove Assertion Re-
garding Sun.
FORESEES BIG DISCOVERY
Research Is Expected to Render Big
Service to Long Distance
Weather Forecasts.


at the last session in making q special
pose, Dr.. O. G. Abbot, director OF the
astrophysical observatory OF the
Smithsonian institution, win be able
TO complete within the next year an
investigation begun In 1905 which Is
expected to prove that the radiation
Of the sun varies and that this varia-
ton produces a corresponding varia-
ton In the temperature OF the earth.
While this discovery, IL made, will
have It's highest value for pure sci
ence, It viii also be Of great benefit in
fits application to agriculture, to long
distance weather forecasts ana other
practical purposes.
To complete the tests which have
been and still are being made at the
observatory In Washington, sea level;
at Mount Whitney, three miles eleva-
ton, and at Mount Wilson, one mile
elevation, DR.. Abbot finds it necessary
to establish a station In the cloudless
region Of southern Mexico. Observa-
tons then will be taken at the new
station and at Mount Wilson simulta-
neously, and If the two sets of meas
urements should agree the conclusion
will be proved.
EXPEDITION STARTS IN July.
Congress has provided for this trip
to Mexico by adding 5000 to the ap-
. preparation regularly made for the
work of the astrophysical Observable
ry. While the expedition will not set
out for Mexico until next July. the
work of preparation already is under
way. In speaking of the work DR..
Abbot says:
when we began to make these
measurements there was nowhere in
the-world any exact scale of measure
ment of radiation, although physicists
had been working devising instru-
ments for that purpose for about sixty
years. Still there remained an uncer-
tainty of to 10 per cent In the scale
of pyrheliometry, as it is called. We
have devised several instruments to
be used as standards for that purpose,
and in the last year we have made a
careful comparison of two of our in
struments of the most improved type,
and these agreed perfectly in fixing
the scale of measurements.
This apparatus is used now as a
standard by which to standardiZe 9th
er apparatus. which has been sent
around the world. We have sent in
struments to France and Italy and
have requests for them from Argen-
tina, Peru and other countries.
"Our measurements at Mount WI
son have been carried on for several
years. The first expedition was in
1905, and we have observed almost
daily for six months OF each year from
1905 to 1910, excepting in 1907. In
1910 I was fortunate In having two
weeks of good weather on the sum.
NIT OF Mount Whitney, which IL the
highest mountain in the United States
carried on there complete measure
ments which were simultaneous with
those carried on at Mount Wilson. We
have found that the results obtained
at Mount Whitney check and substan-
tate completely the work we were
doing at Mount Wilson. Therefore,
having established standard scale OF
measurement and having shown that
we get the same results at Washing
ton, Mount Wilson and Mount Whit
ney, we are now able to state the
value Of the solar constant of radia-
ton. This value is of an Importance
equal to that Of the distance Of the
sun in astronomical work. Our meas
urements show a range OF the value
of the solar radiation outside OF our
atmosphere OF about per cent.
THE METHOD OF PROOF.
"Now, by taking stations so far