Evening star. [volume] (Washington, D.C.) 1854-1972, 1930-11-02
STUDY OF ECLIPSE
GIVES VALUED DATA
Spectrographs Record New
Facts on Inner Corona
of Sun.

BY the Associated Press.
PAGO PAGO, American Samoa,
November IA study Of details found
in spectrographs obtained by the United
States Naval Observatory Eclipse Ex-
petition at Niuafou Island will give
! important information on the motions
in the suns inner corona, OF which the
scientific world now knows nothing DR..
s. A. Mitchell, head of the expedition,
said here yesterday.
The expedition arrived here 18 hours
late aboard the U. s. S. Tanager from
Niuafou, where eclipse observations were
made on October %. A strong gale
between Eiuafou and 'Pago Pago de-
layed the vessel.
Dr.. Mitchell, pleased that the ex-
pedition had been successful beyond all
hopes, made the statement after de-
failing the history and accomplishments
of eclipse observations since the spectre
scope was first used in 1868.
New Line Is Found.
"This latest eclipse brings the dis
covery of a new line in the far red of
the spectrum, a wave length which
showed itself at 6,770 angstrom units"
he said. An angstrom unit Is one
one hundred miIlionth Of centimeter.
two separate photographs fairly strong
and appears as complete ring in no
manner resembling the lines of high
level chromosphere, he continued. The
chromosphere Is the term generally ap-
piled to the suns atmosphere.
THE emission of bright lines in the
corona are visible in q shallow layer
of the inner corona, never exceeding
minutes of arc from the suns sur
face" he said. These lines are said to
be due to a hypothetical element called
| coronium, but what coronium is we
| do not know. Presumably 1t is one OF
the lighter and well known bases which
, has lost one or more external electrons
Such an element is forbidden to radi-
| ate under the conditions in the ter.
restrial laboratories. but can give forth
| light in the celestial laboratory, the
sun. where in the inner corona are
found high temperatures and minute
pressures that cannot be reproduced by
mechanical means.
First Used in 1858.
:, 'The 1880 coronal spectra show
1 splendid details in the spectral lines al
wave lengths of 5000 and STA angstrom
units, study of which will give i'm
portant information on the motions in
the inner corona Of which as yet we
| Know nOL01ng.
| DR.. Mitchell said the first triumph OF
the spectroscope, which tells the con-
stitution Of light, was first used at the
eclipse Of 1858 and its first triumph was
the discovery of helium from a strong
line in the yellow" near the ID" lines
Of sodium. This new element was not
discovered in the laboratory, he said
until 1895 by Sir William Ramsay.
In 1859 the spectroscope scored its
second triumph" he said, 1.-THE discov-
cry Of line in the green, seen at mid.
totality. The yellow line of helium Is
caused by the suns atmosphere, calIeC
the chromosphere, while the green line
Is due to the corona. Since the first
discovery other spectral lines have beer
found during totality, the number beine
about so.
The vast majority Of these lines
however, are not coronal in origin, bu
are high level chromosphere lines
There are only about a dozen line.
that are caused by the light on tn,
corona, the strongest is the green a