The San Francisco call. [volume] (San Francisco [Calif.]) 1895-1913, 1904-08-30
WEIGHS SUNS
HALO OF LIGHT
Professor August S. Ar
rheniuS Finds COrOna's
Heft Is 25,OOO,OOO Tons
SETTLES THE QUESTION
Distinguished Swedish Sci
enlist HarmOnizeS Conflict
ing Reports of Observers
Berkeley ONCE San Francisco Call.

Berkeley Office San Francisco Call,
214S Center Street. Aug. 20.
The corona Of the sun-nOt the sun
itself-weighs something like 25,OOOOOO
tons, so Professor August Svante Ar
rhenius of the University of Stockholm
has discovered after making a visit to
the great Lick Observatory at Mount
Hamilton.
OF course, Professor Arrhenius has
not computed the weight Of this enOr-
nous mass by any such insignificant
scales as there are on this earth The
scales he did use are of the intellectual
kind, utilized in handling big problems
and big figures In other words, the
scales were his brains and the tools
were the atmosphere, the temperature
and the telescope.
To Professor Arrhenius and the rest
of the astronomers 25,000,000 tons, 1t
seems isn't much for the corona OF the
sun TO weigh. In fact, they are sur
prised that it is thus shown to be so
exceedingly light, considering that IT
occupies a space whose dimensions in
every direction amount to several mil
lions of miles.
Besides computing the weight Of the
corona Professor Arrhenius settled one
other great problem that has puzzled
the astronomers for a long time This
problem concerns the sources of the
corOnal light, over which two schools OF
astronomers disagreed. For instance,
Professor w. w. Campbell, director of
the Lick Observatory. and Astronomer
Perrine, his assistant, held the view
that the light of the inner portions Of
the corona is due to the radiation from
minute dust particles maintained at
temperature of incandescence by the
enormous heat of the adjacent solar
Us~rl-M 2 he
outer corona is composed mainly of
sunlight reflected and diffracted by the
colder dust particles composing this
part of the corona. These conclusions
were based upon the character Of the
spectrum Of the corona.
On the other hand the observers Of the
Smithsonian Institution measured the
quantity of heat from the corona and
were surprised TO find that. even in the
immediate proximity of solar surface
the effective temperature was sub
stantially that of the room in which
they were observing. They therefore
held the view that the main source of
light from the corona is not the in
candescence of its particles, but that
the radiatiOns are in the nature of an
electrical discharge.
Professor Arrhenius, however, has
succeeded in haTmOnizing all the re-
suits Of observations by showing that
the particles in the region observed
must be at a temperature of about 5000
degrees Fahrenheit and therefore must
be radiating light by virtue of their in
candescence; but that the particles are
so few and far between that the eff
fective temperature observed is not the
temperature of the particles them
selves, but is the average temperature
for the incandescent particles and the
cold background Of space upon which
these particles are seen, here and there,
in projection. The total area OF the
background covered by the particles in
projection is but minute fraction of
the whole area. The spectroscopic
and thermOmetric observations are
completely harmonized by assuming
that, in the part of the corona OBJ
served, there is but one minute dust
particle for each fifteen cubic yards of
space.