, 1870-12-13

'EhC Sa1af NofUaAy ana FAAuet0Aoss
The great problem which is proposed to bo
soived by observations Of the eclipse Of next
week, Is the nsturc Of tho SUMS c1rona. The
phenomenon IL ya,iou.Iy nsc1ibed to The
prcse1ce Of non-luminous atmosphere ox-
lending 10 4 great 1itt&nce from the suns
body, ind to immensa numbers at aero1itic
particles which circle around him
The latter hypothesis aeems to be the ono
which In nest ID fAynr little mathematical
seaecuing u sufficient to expose us absurd
beginning with thu planet Neptune, the
most distant known, we calculate that bis Pc
nod Of revolution ls e1aet1y tho ssoe which
would have been occupied IN one sotation On
the s1is. by globe bounded By his orbit, aud
haTirg the sun as i centre the mean lxiA
velocity OF ali the PARTICLES Of such globe
being equal to the average axik velocity OF
aslthe particles nov COMPOSING sss asss q
the ease Of ali the other planetary bodies.
We find that the saiue actu4l velocity which
carries tie su1 round once in COZ 3 earth hours
would carry globe Of tho same diameter IS
the orbit Of Mercury rouud on it, axis once
in s. ds5e. From this fact it ia legitimate to
argue that no macs revolving around the Gun
can hare greater mean angular velocity In
the orbit than the A1i1l velocity OF the sun
to-day; it Inust be much less than thAt guam
tity.
1ha pfeaant ANA yaloc1kS OF tne e1u "uula
give to body, situated fifteen millions Of
miIea fsun his surface, Just enough velocity
in the orbit to countefhaIAnce the fosce Of
attExction tow1rd the aun's centre. This,
then ia the limit Of planetary revolution IN
eide Of that limit a body would be drawn 70
the suns surface, unless kept Away by the
mechanical contact Of his xtmosphere- Bnt
the same velocity ~ the atmosphere; In re-
ality, form payt Of il, md be Of the aauh
tpecifc deotity as the atmosphere 1t tho aame
distance
The above.nmed LIMIT OF minimum ia that
| Of mean distance. Some Of :he comefs pass
| miles Of the sun At the time Of pefihe1ion !;
1 but 1t is followed by = cotnreneahng E1eAta1
! apheltou distance.
| 1t ia nonsense to talk about separate bodies
| giving rise to the coruual dispias during ~
telipte. a particle OF matter one miI!l?u
uilsa removed from the SUMS centre would
| need to ttase1 round him tHo and hslf times
| each twenty-forr hours, or Gxt5 times rs rap
ialy ~ the a1ial velocity OF the sun, to fees
from falling to his surface.
! The corona must be m aerial envelope o1
she sun His atmosphere csn extend t1fteet
md oue-ha1f millions Of miles from bis cen
,se, that being tbs diatAEce which have cal
culated - the limit Of equilibrium betweer
tie taueenti1 and the ceuuiPetAt forree the
former being determined By the a1ia1 velocit,
rnoerheEe should be denso eno1gh for tn.
whole Of that distance to reflect Light
In the eau.e way we may calculate =. he16h
Of about - $50 miles ~ The limit Of the earth
atmosphere. No n'oon eoua sttele roand be
tarth's atmosphere loses its rettaeuye powe
xt = height Of SEQ m,lee-or 80 OF that distance
| Aecertirg the same ratio to e1ist in the cA
OF the sun, 1t would GlFe oepth Of I llttl
more th1n 5000, COO uai]es for the corona
snd an Ia about the extent which agrees Wit
the best obse1 yatioua OF past eclipeea
Mercury il. thus, undoubtedly the neares
J ntsre 10 tbs sun, though thege are ceftai
thauccs in the direction of his orbit whic
haye led at,rone 1ncrs to lock for intra-Merc1
nh planets. 70 saeh thS1oss m s,s;t e3ss nut tt
. arc sill facts. May they not be accouuse
~ know that the eA1th's sasss ia anspen
! I'd to IN extent ~tieh has been estimated
Iso tons annually. bv The fall Of naillioaa
d strohtes, which h4veresolvea (eouaet. t. shlo,
4 ID ortats, until they meet tho earth Il her Al
4 | nn.t rnufd ard are dawn to her surface !
: her aupeYipr attraction We have good re-
n rnn to believe that these belts Of plsnstoi
!. 4 cou1re in every direction from the sun, - Il
Comets do, and they Hnst, therefore, be N
Sith u,uch more nuncrpusly In the vicinity
r NeTcnr,'s o1h;t than naAt ths eAsth'n nit
Even KSth the leeteE attractive po3ns Of VI
T. cuty. ths annual augmentation Of his M
.. must be greater than in tho CASE Of the ear,
). 1h;le IT'S e0ect viii b. couespondingly {
{ hsnses, ~ besng IN much h5gef proportion
ID he whcie. Mercury Is little uoFs than l.
aombss. ~ bs,.y i s., ,ooe @ 90 oooo t tos
N Ard. though hare not undertaken thosou
10 mafhemsiicsl analysis Of the problem, I C
T. eirdes from ! gensrll dsscusEson Of The gu
dou. tbat IA annual adtitiun uf about 600 K
Il lfon falling aerphtes to tho nass OF MeFcs
Tould b. more than sufficient u produce
nhsnumena which h7vs hittstto pfoven
ID perplsxng 10 astzouomsss- &. ooaoxxz