The Bossier banner. [volume] (Bellevue, Bossier Parish, La.) 1859-1952, 1882-11-30
COMETS.
FFoi' Proct0r's Views About Comets
s'n2 and Their Peculiarities.

WILL
FreI. PrOctOr's Views About Comet,
sra and Their Peculiarities.
10 fhe Editor Of the Nep York Herald.
During the last two years MANY comets
some of them bright ones. have beer
seen, and from all sides the question
reaches me, Do we know more abou,
comets than we did two years ago?
wish that L could honestly answer. We
know great deal more; but cannot.
sun, something has been added to our
knowledge, and, unless / mistake. al
though that something NAV in itself he
siaght, the manner in which it has been
learned is such that the small modicum
eofnew truth is full of promise.
suppose every one who reads these
lines knows pretty well what are now
the chief difficulties in cometic science
we want to know why, as the comet ap-
proaches the sun, it throws out all around
shout chiefly toward the sun, the lum-
nous appendage we call the coma or
halr-really, SO far as we can Judge, a
nepulous or gaseous envelope We
want next to know why the matter thus
thrown out seems to become subject to a
repulsive force by which it is strongly
arven from the sun to form what is
called the comets tail. We want to
Know how much of the light of the COM
et nucleus (or brightest part coma or
neptdeus surrounding, and tail is due to
The mere reflection of sunlight and how
much is inherent. Also, having ascer-
tanned beyond all possibility of doubt or
caVil that part of the light in all three
cases is inherent, we want to know how
sufficient heat is acquired to raise
nucleus, coma and tail to actual inher-
ent luminosity.
Now, in former years, and especially
during the appearance of the comets of
Wnneeke and Brorsen, in 1868, astrono-
aners recognized that a part of the light
OF some comets, at any rate, is due to
the inherent luminosity of certain COM
pounds of carbon and hydrogen. DIR.
William Huggins, of London, is not a
very daring scientific, speculator; he
usually errs on the side of excessive eau
ton Qndeed l have myself been stating
respecting his sresults for the last fourteen
years, what he now only begins to state
TOT hlmselfO therefore, when he does
speak positively we may believe that he
mas found the evidence overwhelmingly
strong. Well. he says in lecture very
recently delivered before the Royal In
stitution: ''The general close agreement
IN the case of some twenty comets of the
bright bands in the cometary light with
those seen in the spectra of hydrocarbons
Justifies us fully in ascribing the light of
these comets to matter which contains
carbon in combination with hydrogen"
Until quite recently this has been the
only matter which has been clearly rec
oognized by the spectroscopic method as
forming part of the substance of comets.
And the wonder has been that substance
so refractory as carbon-a substance |
which cannot be vaporized in our labor
ata1es under any ordinary conditions
should thus appear in the form of lumin-
otls vapor in the case of comets further |
from the sun than our own earth. 1t is
sulf1cult to see where the heat can come
from by which the carbon present in
these bodies can thus give light-evidence
(which means also heat-evidence) of it's
presence. 1t is not carbon only which
Is thus shown to be present, nor even
carbon and hydrogen only; nitrogen
seems also to be indicated. Professors
Llvelng and Dewar have found that GER
tam bright lines are only present in the
spectra OF certain compounds of carbon
when nitrogen is also present, and that
In factthey indicate the presence of cyan
ogen, well-known nitrogen compound
ofearbon. Now these bright lines have
not only been seen, they have been pho
'ographed in the spectrum of the bright
est comet of 1881 (by DIR. William Hug
gins London, and by DR.. Henry Draper
IN IN New York;. A part, then, of the
ngnt OF every comet is inherent and
comes from luminous mixture of car
Don, hydrogen, nitrogen and probably !
oxygen also. A part of the light, is,
.however, reflected sunlight, nearly the
whole of the tails light being thus re-
nected, and great portion of the light ,
q the coma, with a smaller portion of
,ne light of the nucleus. Even $
here, however, we cannot be as !
sured that all the light which might be |
renected sunlight is really so. The only i
way In which we can distinguish such G
.Aght from inherent light coming from \
glowing solid or liquid matter, is by !
noung that when we analyze reflected t
sunlight certain tints thousands of them) {
are missing, SO that across the rainbow h
united streak, into which the spectre +
scope resolves such light, there are seen t
numbers ~ OF dark lines corresponding to v
.nose missing tints. In the case of light a
nom self-luminous solid or liquid mass ]
no such dark lines are seen. But the n
ialnt light of comet is not very easily n
ahaiyzed as closely as is necessary to c
snow whether these dark lines exist in it a
or not Until quite recently astronomers D
nave been content to regard the presence s
ol continuous rainbow-tinted spectrum, a
with or without lines. as evidence that $,
N me comet shone by reflected sunlight. q
Sew, however, a closer scrutiny has {