New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1878-08-02
FURTHER POINTS AB0UT THE ECLIPSE.

FURTHER POINTS ABOUT THE ECLIPoE.
The details of the observations OF the late solar
eclipse reach us slowly and in very frasmentary and
confused form. The great point to De decided was
as to the nature of the corona or halo OF slivery
light which bursts ont all around the sun the mo-
ment the suns disk is wholly covered by the MOON
Ia this corona self-luminous, or does it shine
by reflected Light If self-luminous, is it
composed of one OF several constituents, and
are these solid or gaseousi Now, in de-
Gliding these questions everything depends
upon the revelations of the spectroscope. In that
instrument a self-Iuminous solid or liquid body
0iyes n streak of rainbow -colored light, running
from red to violet unbroken by lines OF any KIND
This is known as q simple continuous spectrum. A
sef-lumnous metallic vapor or gas gives spectrum
composed of only few bright lines. IL the light
from solid or liquid substance passes through
LAYER of gaseous matter before reaching us, some
of il ia absorbed and the spectrum is crossed by
number of dark lines. The ordinary spectrum OF
sunlight belongs to this last class. 1t is continuous
spectrum crossed by dark or Fraunhofer lines as
they are called after the name OF their dlseoVerer
and this compound spectrum shows that the light OF
the sun comes from an incandescent solid OF liquid
shining through a layer OF envelOp of metallic
vapor or gas. The spectrum OF reflected sunlight Is
of precisely the same nature-a continuous spec
trum crossed by dark lines.
These elementary principles furnish simple key
10 explain the meaning Of the recent eclipse obser
vations Was the spectrum continuous Then the
light was caused by glowing solid or liquid body
Were there bright lines in this continuous spec
'trnm7 Then some portions of the light were due
aIso TO incandeseent gases. Were dark FTaun-
hofer lines PRESENT. Then the light had passed
through gaseous enveop. Everything, it Will be
seem depends on the facts OF observation and 1t is
here that the evidence is unsatisfactory No OBJ
seryer-with a single excepti0n-saw any dark
lines in the coronal spectrum, and the bulk
of the testimony therefore is altogether
against the theory that the corona shines
by reflected sunlight. But DR.. Draper would
seem 10 have discovered these lines. HIS photo
graphs of the corona, IL is claimed, give not
merely simple continuous spectrum. rs
telegraphed at frst but continuous spec
trum crossed by the usual Fraunhofer lines. IL
IS further claimed that Professor Draper saw no
bright lines in the spectrum. These facts If fully
established, are important, since they would show
that the corona's light is simply reflected sunlight.
II Is little strange that no other observer noticed
these lines bnt II the evidence Of the photographs
is clear and decided, so much greater is the credit
due to DIR. Draper. Another point favoring DIR.
Diapers conclusions is found in the fact that the
RAYS of the corona furnish proofs Of polarization,
thus showing that they shine by reflected and not
by direct light But, az we have said the evidence
is vet imperfect and even contradictory. DIR. ORA
per for instance reports that Professor Barker dis
covered these dark lines. whereas Mr. Lockyer
distinctly states that Barker failed TO find them.
On this point further details clearly necessary.
On the question Of the appearance of the bright
lines in the coronal spectrum there is less con-
nict of opinion. The few lines seen appear
10 have been observed only in the chrome
sphere near the suns surface. In the cOrona
proper there were apparently none, and Their
absence is really the most surprising result o.
the eclipse. On all previous occasions they have
been detected in the upper parts OF the corona aud
their presence has proved the existence Of mean
descent gases surrounding the sun at immense dis
tances aud evidently projected and sustained
there by intense solar forces. The absence
Of these gases now points to much less active con
diton of the sun than has been observed in former
eclipses-a change IN fact marked that Mr.
Lockyer describes it as something wonderful The
sun has thus been shown to be subject 10 greater
variations than had been suspected from previous
indications, though in the opinion of most Of the
observers these fluctuations are still too small TO
have any noticeable effect on the eartRs climate.
Assuming 1t as probable, then. that the corona
shines by reflection, what interesting field of
speculation opens before US. What is there IN the
corona to reflect the suns lighti Is it cosmic
dust, single particle of which in cubic mile OF
space would. according 60 Professor Newcomb,
shine intensely when exposed to such flood Of
light as the sun ponn ont on every body in his
neghborhood Or Is the sun surrounded by clouds
of minute meteors, ever revolving about it Or
are streams Of meteors similar TO those we see Oc
casonally in our own atmosphere, constantly rush
ing into the sun from all parts Of the solar system
Is the suns heat kept up by such meteorc showers
These are some Of the interesting questions which
naturally spring from DIR. Diapers photographs.
Perhaps before another total eclipse comes round
science may be able to give definite to these
speculatiOns.
An announcement extraordinary" which reaches
ma from the Grand Union Hotel at Saratoga, begins