Centre Democrat. [volume] (Bellefonte, Pa.) 1848-1989, 1882-06-15
The Suns Corona.
Philadelphia Record.

Egypt u observe the total cclips ut the
sun on the l7lh of May will not be
made public for some little time: but
the reasons tor making the observations
are worth knowing In advance. An
eclipse of the eun Is not uncommon
event. but an ordinary cclip-e rcycul-
little OF value to the astronomer. In
the course OF the revolution Of the earth
aud moon about the sun the moon
reaches a point where part Of It's cir
conference intercepts some of the suns
rays that would otherwise fail upon the
earth this is partial eclipse. But
when the position OF the moon with
reference to the sun is such that line
drawn from the centre OF one through
the centre OF the other would strike
any point on the earth's surface there is
n total eclipse at that point, because
the moons disk Is apparently imposed
upon the suns. The solar rays are
wholly cut or from view. But the moon
apparently covers the sun by 20 little
excess OF size that at the exact instant
when one disk covers the other there il
visible around the moon edges bright
ring of apparently turbulent, shooting
flames, extending from the sun far be.
yond the limits OF its body. These
flames, or the corona as they are called,
are not visible owing 10 the excessive
bfilliAucy OF the sun itself except when
the interposition of the moon cuts oil
the binding rays direct from the suns
globe. 1t r. this corona which is the
cause Of curiosity and scientific interest
The London Pail Mail Ga-l,fe gives
ant,, A i, .rn.t,,r ,r rfnrp,ati,,, ,l1t,t 4 q.
phenomenon. showing how difficult It
Is 10 form theory to account for II
that will satisfy all It's known variable
conditions. The reason for knowing
80 little about 1t ~ the difficulty OF ob.
serving it. 4 total cclirsc occurs oulN
every second year, and the time during
which II lasts Is not above three mln.
utes. Frequently the place on lhe
cBrth's surface where the eclipse is to-
tai Is inaccessible, and even when it
has been reached cloud. have intcricr.
eel. 1t ~ only within the lA.t century
that serious efforts have been made Co
learn what the corona l., and the study
has been materially hId.d by uhs eryrtp
It's spectrum and by the use Of photp.
grarhy. It's an important matter to
determine whether the corona slonr-
to the sun or to the moon. or whether
u IA mere optical illusion, du" 10 the
eye or 10 the medium through which
We see II.
ln the frat place, the corona is ye-y
variable ~ us appearance. IL never
look. twice alike TO The sane observer
It even gives different impressions TO
observers at the same time and place.
IL consists in general of vast sheets or
s,reamcrs Of light. somc'hirr like those
OF the aurora borcbills ca clos. c1ami.
nation, however, It seems IN be- com
posed oi small lun't riuR oliirc, lrok
On here and ther" rs -iiil more daz
King Jet, ,oi irreruls flame. and of large
outer ring o. lr.s intense light, broken
up st lls edges into hclts sui streamcr-.
Sometime u looks very wide. uud
again very narrow IN spnls. ani % has
even seemed to take almost the shaJe
Of a cross. The strcRmsrs appear TO Lc
brightest between tLcsuu's equator aud
It's polcs. Owing to the variable iufm,
IN which It appraTtd to- .i.r"nt otssr
yers IL was at fr,i thought that the cor
ona was non existent Iu fact, lut that
the effect WAS produced hy something
ia the human eve or IN tho sarth's at
mnsphcre A'roisssors Young and ilatk.
uc-s shosel, however, that the cRuec-
trum oi the corona light contained a
bright line such as could have been
produced only by an iucandcscent gas.
This experiment proved that the corona
was reality, Hnd moreover that if'was q
part oi the solar action. since there il
no incandescent gas in our atmosphere
or IN the moons This bright line was
80 situated In tho spectrum ~ to lead
its discoverers to believe that il vas
Characteristic of the presence Of iron
but afteTward IL was found not 10 he
due 10 iron, but 10 some other substance
with whose qualities We are as yet unac.
quainted, it IL known only that il is
lighter even than hydrogen, and this
would accord with its presence outside
Of and apparently floating upon the by.
drogen OF the chromosphere. Besides
this unknown substance, the corona IL
found to contain little hydrogen, and
lines in the spectrum indicating other
constituents have been doubilully oh.
served. Besides the incandescent gases,
there appears to be large quantity Of
non.luminous matter in the form OF fine
duit or cloud.
1t is reasonably certain that the coro.
ma is directly connected with the sun.
and is not merely a meteoric mass
sklmming around II. Ii bears a sym.
metTical relation to the suns axis, and
the streRmers are most abundant in the
zones where sun spots are largest.
During the total eclipse Of 1878, at
which time there was a minimum sup.
ply Of sun spots, the corona was less
bright than usual. The main mess of
the corona would seem to be made Of
iBcandescent gaseous matter. and there
have been as many speculations about
the strssmers as there have been about
the luminous tails Of comets or the
constituent parts Of the aurora beams
IL is probable that every observation Of
the corona will increase our knowledge
Of its characteristics. and for this reason
the results of the English expedition
will be awaited with great interest.
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