The Lake County star. [volume] (Chase, Mich.) 1873-current, 1874-08-06
What Is Known OF Comets COntradic.
lions OF Scientists.

In a paper published last year in
Poggendorffs Anndten, Herr Vogel, the
best of authorities on celestial spectre
scOpy, gives summary Of all the obser-
vations of cometary spectra known to
him, and comes to the startling conclusion
that the. spectroscope does not show
comets to be composed of hydrocarbons,
and does not reveal their nature. The
following is the nature of VogePs sum-
mary:
The first comet examined with the
spectroscope was Comet l., 1864, by
Donati. Result three bright bands not
cOinciding with those Of the hydrOcar-
bon spectrum.
2. Higgins and Seechi observed Tenn
pies Comet l., 1866. Weak continuous
spectrum in which Higgins saw one
bright line and Secchi three no coinci-
dence with hydrocarbon spectrum.
3. Higgins examined Comet 2, 1867.
Continuous spectrum bright lines sus-
pected. Probably no hydrocarbon.
4. Higgins and Secchi observed Bror-
sens Comet l., 1868. Spectrum similar
neither to that of nitrogen nor hydro
carbOns.
8. Higgins and Secchi observed Win
neck's Comet 2, 1868. The measurements
and comparisons of Higgins showed
agreement of the comets spectrum with
that of defiant gas. Secchi's measur-
ment showed the sharply defined side of
the middle band Coward the red end)
nearly conceded with the line group b
of the solar spectrum, at which part also
the beginning of the middle band in the
hydrocarbOn spectrum is situated.
6. Comet L., 1870. Wolf and Rayet,
observers. Three bright bands not ac-
curately determined.
7. Comet l., 1871. Higgins and Vogel.
Higgins found three bands; Vogel only
two. Spectrum apparently identical
with that of Brorsen's comet.
8. Comet 3, 1871 (Encke). Higgins,
Young, and Vogel, observers AS usual,
spectrum of three bands. Higgins
thought this agreed with the hydrocar-
bon spectrum, but Vogel and Young
found no such coincidence.
8. Comet 4, 1871 (Tuttle). Examined
only by VOgel. Three bands, whose
position, accurately measured, showed no
coincidence with the hydrocarbon spec
trum.
OF eight of these nine comets, five
q, 2, 4, 81 show no agreement with
the hydrocarbon spectrum. In No. 3,
the presence of the bright lines was only
suspected. In No. 8, Higgins observa-
tons were at variance with Young's and
VogePs. There remains only Comet 2,
1868, for which Higgins and Secchi's OBJ
servations assert merely Il probability of
coincidence of the lines in the spectrum
with those in the spectra of volatile
! hydrocarbons.
From all these facts Vogel draws the
conclusion that it is very questionable
that comets consist of such matter (hy-
drocarbon) as they are commonly
thought to consist. We should be con-
tent with the deduction that a portion
of comets light is its own, and very
probably from glowing gas. A brighter
comet may throw more light on the sub
ject, yet it is extremely difficult to deter
mine the nature of the glowing gas
through comparison of spectra from
the electric spark in Geisslcr tubes;
since in the comet there must be circum-
stances of pressure and temperature
which it is impossible for us to initiate,
and through which it is known the spec
trum is greatly modified.
In an analogous manner Vogel shows
the mistake of DR.. Zenker in his asser.
ton that {" in the spectrum of Brorsen's
comet Higgins has recognized the bright
line of nitrOgen"---since the bright band
in the green of the spectrum had nearly
the same position as the brightest line OF
the nebula which comedies with the
double line of nitrogen. Neither is there
reason to suspect water-vapor in comets
In fine Vogel thinks that too much
credit for accuracy has been given to the
spectroscope itself, and the deductions
from the spectra are far from conclusive.
---New York Graphic.