Hannibal journal. (Hannibal, Mo.) 1853-1853, 1853-09-08
COMETS

New that one Of these magnificent NlsiterS
has so lately been seen in our western evening
sky, our interest is naturally excited 10 know
something more in relation TO them.
Comets are flaming metecr>, Of peculiar
appearance, having brighter or denser head,
or nucleus, aud either a surrounding hazy
brightness, or long, bright, hairy train, or
tail.
What is their composition is unknown, and
various are tie conieotures concerning it. II is
certain that they contain but very little matter,
for they exert but little influence upon bodies
near which they pass. The nucleus Of some
appears opaque, like planet. That Of others
is transparent; and others, again, have no nu-
cleus, but are transparent throughout their
whole extent. The envelop, OF train, or TAIL
is more or less thin and transparent, and the
stars and other heavenly bodies are seen
through it.
When comet is seen at distance from the
sun, through a good telescope, it resembles a
dense vapor, surrounding the nucleus, and
flowing far out into the regions of space. As
it approaches the sun, its light gradually be-
comes more brilli,r', i'll 1t comes nearest 10 the
sun, when it piares w!th light inferior only TO
the sun ii>'G.
When comet, as is usually the case, has a
TAIL this tail, train, is always turned from the
sun; so that, while the comet is approaching
the sun, its train foliors it, but when it is de-
parting from the sun its train goes before it,
often our,ing forward in TIE direction toward
which the body is going.
The substance Of which the train is composed,
as we'll as tina; Of the body itself, is hid in mys-
terry. "Tycho Brahe and Appian supposed their
tails to be produced by the rays OF the sun,
transmitted through the nucleus, which they
supposed 10 be transparent, and 10 operate as
lens. Kepler thought they were OccasiOned by
the atmosphere Of the comet, driven of by the
impulse of the suns rays. Sir Isaac NewtOr
conjecsured that they were a thin vapor, arising
from the heated nucleus, as smoke ascends from
the earthi while Dr.. Hamilton supposed then
TO be streams OF electricity"
The shape and number OF these tails is otter
remarkable. The tail of a comet in l74I formed
nearly quarter Of circle; and one in 1855
was curved like Turkish sabre. The come
of l744 had at one time sir tails, which ap
peared and disappeared in few days. Tn,
comet of 1923 had tlrO tails, one extending to
rad the sun, and the other from it. And one
comet appeared with lis tail at right angles, o.
quaHering, 10 the sun. Sometimes the train
are Of vast length; that Of the extraordinary
comet of 1850 extended from the zenith TO IL,
horizon, and was 5000, 900 of miles in length
and that of 1871 was oO,O00,O 900.
Comets are peculiar for the form Of thei
orbits. The orbit of planet resembles Toun'
soh'si; that OF a comet resembles wheel fiat
tened, or much longer in one direction than il
the other.
They are also remarkable for the rate of ihei
motion. As they 90 farther from the sun, thei
motion becomes slower, and continually slower
as they travel away into the mighty depth o
space; while, after they have turned and sgail
approach the sun, their motion becomes CONT
nually quicker, until at length, when the!
wheel arcuai The sun. rt ,ho1t distance frou