Year: 1874

INC SpcctrOscOpy OF tho NeW SOmots


The spectroscopic analysis of the new
comet seems to have so far been very imper-
feet, and it is by no means certain our
astronomers will determine the constitution
of the brilliant meteor. When spectrum
analysis was first applied We were promised
disclosures IN the domain of stellar and solar
physics as great as if the chemist could move
his laboratory to the most distant star and
analyze its texture. We have, however, reaped
but little of the promised harvest And. as
for cometary analysis, we may safely conclude,
with one Of the most eminent German spec
troscopists, we shall have no decisive evidences
regarding the physical nature of comets until
one appears of such extraordinary brilliance
that it can be examined in all its phases. Such
is not Coggia's comet If the physical texture
of comets were known spectroscopically, or
otherwise, doubtless the interplanetary in
huence of these bodies would be understood.
We know that olefant gas is present in the
new meteor, as it was in Encke's comet in
1871, and in the second comet of 1868,
examined by Higgins. We know, too, the
character of olefant gas as the absorber of
the calorifc waves of radiant heat; and it is
easy to see that a vapor screen of olefant gas,
stretching like Coggias comet (and of the
same size) across the heavens, would exert a
powerful thermal influence. Experiment
shows that where such vapor of carbon is
interposed it cuts offand quite arrests the radi-
alton which seeks to penetrate it. 1t acts as a
dam to divert or stop the obscure rays and
thus becomes an agency for accumulating
heat. This agency is so powerful that about
seven-ninths of the heat waves are absorbed.
Such an agency, if it was brought within our
atmosphere would be attended with the most
marked results, electric, thermometric and
otherwise. But the gaseous, cometary mat
ter, while opaque to the heat waves or obscure
radiation of the earth sunwards, does not
arrest or sensibly retard the suns radiation
earthwards and in the present case the dis
tanGe of the comet from the earth, even when
at perigee on the 22d inst, is so great (be-
tween twenty-five and thirty millions of miles)
that its agency in producing high temperature
on the earth is impossible.


1t may be, however, that the cometary
spectra, when reliably observed will show
the presence of other substances besides ole
fant gas. 1t may be that among the elements
of the celestial wanderer will be found
hydrogen, nitrogen, the vapor Of sodium, OF
gaseous substances, which, while allowing the
passage Of the earths heat when radiated
sunward, refuse the suns rays passage through
their interstices. In that case (and it is far
from insupposable, since hydrogen. nitrogen
and other elements have been found in the
spectra of nebul@) We might anticipate the
intercepting of the suns heat supply to US,
and reduction Of terrestrial temperature for
the time Of the comets perigec We say time
of periges because that is two days later than
the period when the comet will be directly
between us and the sun, and hence in the
best position to arrest solar radiation.


| We shall look with great interest for the
spectroscope to reveal the full texture of the,
comet