The evening telegraph. [volume] (Philadelphia [Pa.]) 1864-1918, 1869-12-21
THE SUNS CROWN.
From the London Spectator.

From the London Spectator.
A circumstance has just been brought to light
through the careful study of the photographs of
the recent total solar eclipse which Is full of in-
terest and significance. When the sun is totally
eclpsed there springs suddenly into view a
glory of white light, resembling the ntrlbus with
which painters surround the head of saint.
Astronomers have agreed to call this appearance
the Corona; but hitherto they have been per-
picked by doubts whether this crown of glory
belongs to the sun or the moon, or whether, in
Ane, il is formed by our own atmosphere
If we briefly consider what is commonly seen,
we shall be the better able to appreciate the in
terest and importance of the discovery which
has Just been made respecting the corona
AS the moon is about to hide the last narrow
streak of the suns disc, the first signs of the
corona make their appearance. But only when
totalty has commenced does the phenomenon
present itself in full splendor. 1t is no faint
CLEAN, like the light of a twilight sky. II had
imagined" says Mr.. Baily, speaking of the
nous appearance, would not be brighter than
the faint crepuscular light which sometimes
takes place on summer evening. was, how
ever, astonished at the splendid scene which sud-
denly burst upon my view. All round the eclipsed
sun, to distance equal to about a tenth
of his apparent diameter, there is a brilliant ring
of light, which appears, under favorable cir
cumstances of vision, to have well-de6ned
edge. But this is not the complete corona.
Beyond the edge of this ring of light eXteu1s
q fainter ring, sometimes spreading out into
rays or streamers, which extend some eight or
nine times farther from the eclipsed sun than
the bright inner circle of light. The color of
the corona is commonly described as white;
but there can be no doubt that when seen through
pure atmosphere it presents tints of red, yell
low, and blue.
Such is the corona as seen by astronomers
But the question will at once arise, what is the
real position and what are the true dimensions
of this beautiful object? Of course, if we regard
it as a mere optical phenomenon produced by
n1Ir nNUn ot m uyn N God nnt try f0 find
answer to these questions. The appearance of
the corona, its apparent figure and its variations
of figure would then have merely meteOrOlogi-
cal interest, apart, of course. from the optical
questions they involve If, on the other hand,
we regard the corona as real solar
appendage, we are forced to consider it as
one of the mostj important and striking fea-
lures of the solar system. The ring of
brighter light around the sun is then seen
to represent globular shell about 10000 miles
in depth, and surrounding the whole mass of
the central lumnary OF the planetary system.
The fainter part of the corona become an even
more astounding phenomenon, since looked on
as a solar appendage it represents shell of
matter fully 100000 miles deep in every part,
and forming with the sun, which it enCloses,
sphere some two and halt millions of miles in
diameter-the largest sphere of matter which
the science OF astronomy presents with any GER
tainty to our consideration. But if the corona
belongs to the moon, its dimensions shrink into
relative insignifcance; in fact, our own earth
is larger globe than the coronal sphere so
understood.
The question of the corona has long been
seen to rest between the two former solutions
bailey rather favored the notion that the corona
is lunar phonomenon but he admitted that
one whose judgments he ''must always revere"
Che REFERRED doubtless, to his illustrious friend
Newton) held contrary opinion. We now
| know very certainly that the moon has no
| atmosphere whose extent we can measure-cer-
tainly no atmosphere approaching in extent
| the dimensions of the coronal rings.
| During the great solar eclipse of 1868 very
| little attention was given to the corona because
astronomers were very anxious to determine the
| nature of the rose-colored promiaences. But
| from the few observations which were then
| made, the question whether the corona belongs
| to the sun or is phenomenon of our own at
| mosphere was left an open one. 1t was hoped
| that the problem of the corona might be solved
during the total eclipse which occurred last
| August in North America. At first, however,
| the results of the observations seemed more per-
| picking than any which had yet been presented
to the notice of astronomers. As Mr.. Lockyer
remarked they were bizarre and puzzling in the
| extreme" They seemed to point to the corona
| as permanent solar aurora, since some OF the
observers found in the spectrum of the aurora
the same bright lines which belong to the spec
trum of the aurora borealis.
| so perplexing did this result appear, that Mr..
Lockyer was disposed to doubt whether some
| mistake had not been made. The results of his
own observations had led him to the conclusion
that the solar atmosphere in which the red
(
as the enormous dimensions of the corona would
imply, If the corona really were solar
atmosphere. 1t will be known to many OF
our readers that Dr. Frankland and Mr.. Lock
yer have worked together in this matter, and
they have found that the appearance of the bright
lines belonging to the prominences can be taken
as means of estimating the pressure of the
atmosphere in which those prominences appear;
and the result of their observations pointed, as
we have said, to relatively rare atmosphere
But now would seem that little further doubt can
eentertaned respecting the fact that the brighter
coronal ri1g. at least, belongs to the sun. For
| on careful comparison of the photographs
taken during the recent total eclipse, it has beer
found that the disc OF the moon rGUeLted oUeT
the corona; and further that the corona
presented the same appearance as seer
from widely separated places. 1t will be re-
membered that photography gave in the same
way the first evidence of the true nature of the
colored promlnences. 1t was discovered during
the eclipse of 1860 that the moon travelled over
the prominences, and so astronomers pronounced
deeisiyely that that these objects belong to the
sun. 1t would appear quite certain, now
that the corona is also a solar appendage.
But how are we to get over the ditficutie
suggested by Mr.. Lockyers observations L
seems perpleXing in the extreme to regard thu
corona as solar atmosphere, because, were i
really of this nature the pressure at the surface
of the sun would be inconceivably great Ant
again, there are mechanical reasons forAdoubt
ing whether an atmosphere of such nature
could exist around body rotating so rapidly q
the sun. Is 1t not conceivable that the coroni
may consist, as Mr.. BaXendall recently sug
gested, of cosmical bodies travelling around the
! sun? We know that such an explanation ha
| long been given of the zodiacal light and tina
, light has been found to be similar in characte
, to the aurora borealis. May not the corona b
simply the denser part of the zodiacal light
[ ! Only then there is this difficulty. number o
cosInical bodies, if shining by their own light