, 1874-07-06

Al1lt tHnllDIu-11nhll IN ohao ~ IL "ohN1lHa
one seyen- -hundrodtE Of Tbs earths L-.e which
would be about ono-ninth part Of tho "elsht OF
tho moon.
F1ArrEn1sa coMrARtaoy.
Hoportor-Thnt would compare favorable with
tho larBeHt aBtoroids2
Prof, 8aGortl-Ycs.
Reportor--You think theyo is no danger. Of
accitont arislnR from TIN noareat approach OF
the comets tail to tic csrth2
Prof. sanord-Certainy not.
neportor--That thors will DO no approciablo
ecoratlon to our, ,atmospnoEc7
Prof. HaffcrdANo.
naporter--Ant TINT no nnei bo In no fnnr Of
having to roViHo our methods OF calculating
ec1paes Of tho sun III consequence OF phangoB
In tho rofraction Of light coming atound tho
body Of tho moon
Prof. sat1ord-Not in tho 1caBt; 1t will not
evon 1aiae the ratio Of insurance.
PROF. DELAFoNTAINE.
Nonorter-Havo you n>ado an observation Of
the spectrum OF the comet?
Prof. Da1afontaino-YeB.
Roporter-Did you obtain 3 satisfactory spec
trum7
THE SPECTRUM.
Prof. Dolafonsafno-Ncll,t could not make It
Us complete AZ wanted to still, lavo arrived
Ut some conclusions. There Is no doubt that sle
nucloua OF tho oomot ia composed Of inoandon-
CSuk Baa WU8HQF0 1853 LuAu kEat u
air st the oarth'a surface. The spectrum is not
continuous QUO, mado Of tho sovon primary
colozs, as It would bo II tho comet wero solid,
liquid, OF highly eomprossoa gas In m incar-
descent state. In other words. Tho fact that tho
spectrum ia discontinuous Quo, made OF Bov-
cral bright bands separated by dark spacos,
proves that the nucleus OF tho comet Ia an in
can;(eaont, raretiod gas.
napo1ter-Doas tho spectroacopo give any ilea
as to
TIE NATURE OF TIE oAa7
Prof. Delafontaipe-Tho observers or the
NstronomerB wlao haTo studied tho spectrum nf
comets pretty noarv asroe In finding tleso
bright lines In tho s,octra Of most Of tho OBJ
Berval comets. Truly, thsre aye aome exceptions.
but they may DO accounted for in two ullrerout
Ways. Some comets may havo b composition
two obAorvorB like HuggnB and socohi dluugroo
Ebout tho number OF bands found in tho H,uu-
trum Of Temples comet OF 1866, it IL very likely
that 1t ia owing to tho conditions Of our nt1nos-
phera and tho nature OF the instrument. For
instance, secchi found three bands, Huggins
only one, in the spectrum OF tie same comet.
Noporsev--What doca the position Of thoss
three bands indicator
WHERE THE BAyDs ARE.
Prot. Delafontaine-0no Of then Is in tht
yollowish Eieon, another nearly III the middle Of
thegreon, end the third, Hhioh seomsto be fanter,
IL 10 tho b!uish 2seen.
Reportor-very near tho middle Of the Visible
spectrum
I,of. Delafontaine-Yes It ia highly proba~
bio, II not certain, TINT these three bands iud-
cato tho rreAencs Of carbon, OF ono Of lts opm-
pounds. Generally, besides these bright bands,
the comets give faint continuous spectrum. !
saw no trace OF continuous spectrum the other
night. eecchi. who has recently observed the
sano star or body, dues not mention that There
arc II that respect great differences among tho
diGescnt comets. III some Of them tho contin-
uous spectrum u such as TO make tho bright
bands hardly y.sib!e, whiIo IN others it Ia very
faint. 1saw three bands at least, tho brightest
brightest h tas greoSish bluo. Ehess aso m pross.
bly, ono or Two other bauda, although thev
are stsr aS Sn0Dsa tSaa aea BY SsSsa Sa1 nHos u T.
oniy two bnnds in cogeia's comet, without,
however, statlng expressly that there wero no
others,
Noportor-At the time OF sccchis obaorra-
tlons tho comet waa much loss brilliant than
nov?
STARTLING COINCIDENCE.
Prof. Dsafontaino--Yes, OH tho 18th OF May
whom the Comet WAS scarcely visible ~ star of
tho sixth magnitude. lie gnyg the two principal
bright bands were found to coincide with tha
balida Of carbonic oxide and carho.,ic acid.
Rcposter-Mhat would the continuous Bpee~
tr1lm you spoke Of rs having boeu Hoeu IL somo
comets intllcatof
prof. Delatontaine-It would probably indi-
cato tho presence OF eome solid matter floating
in the nucleus, or surrounding 1t, and reteaslng
the light Of the SUI.
Acporter--1a uot carbon generally solid i?
pruf. Dolafontaine--Carbon IL always observed
IN solid state, aad it Is ona Of the most rafrao-
tory substnnceg known to tie chemists.
Roportor-la thore any reason to suppose,
then. tint tho head ot tue cpmst consists Of oar
bon In highly co,nminuteu atate-sollu carbon
In very small partlclea2
Prof. Delafontaine-If It were 40, then tbs
spectrum would be continuous QUO. The cur
bon muat bs there Ia combination IN gasoouB
atato.
FnoM A COMET TO 4 CANDLE.
Rnporter-4ou have mnie Bome obBeryntions
between tho spectrum of the comht and thoso Of
tho flame Of q candle. have yon not?
Prof. DGinfoutatne-Yes. It you roint tho
tilt of tue spactruscopa upon tho base Of q ea,s-
t'lo 1ame-tIat is, tue dark part which surrounds
Tho wek-you will SEQ three bright bands,
the eoDy, appearnnce, and location ct which
Et.ree worry we'll with thoso Of tho cotuctarY
HEoctrum; and Furthermore, you will observe
faint continuous spectrum which Ia sometimes
bright enough to obl1toiate the bright banda Of
carbon Of tue spectrum proper. Therefore,
should not wonder at all II tho nt-
cloua Of coInnts should bo made
Ut Houle KaHeous oarhon compound,
undergoing at the aalna time process OF partial
decomposition, not to sar combustion, that would
Get free como PARTICLES Of solid CARBON, tho samo
rs ws SEQ them aoating In caudle lame, the
presence Of Which solid PARTICLES would account
1;or the faint continuous apocstum observed by
different Astronomers.