Virginia free press. (Charlestown, Va. [W. Va.]) 1832-1916, 1835-10-22
HALLEY,S COMET

HALLEY'S COMET.
We feel ourselves indebted TO the
Principal Of the Alexandria Boarding
School for the following interesting
notice Of the Comet, which is now WIS.,
iblc and attracting so much attention.
.7ier. Ga-.
The interesting body is now dis
tinctly visible to the naked eve in the
evening. in the northwest part of the
heavens, and being within the circle
OF perpetual apparition, it does not set,
but remains visible during the whole
night. Its apparent motion amongst
the fixed stars, is at this time unusually
great, owing to the direction of its mo-
tion and ITS great proximity to the earth.
being only little over p millions of
miles from the earth, or less than one
fourth Of the distance that the earth is
from the sun. II will approach but
very little, If any, nearer TO the earth
than It is now, and will be the brightest
within about a week from this time
IL Is in the constellation Ursa Major
and about 7 o'clock on the evening of
the 10th IT was few degrees north
west Of DuJhi, the Northern Pointer,
as 1t is commonly called, and last even
ing little northeast of .7Iiofh in the
tail OF the Great Bear, having gone
through about degrees of the hea-
vens in % hours. Before the moon ri
ses. the comet exhibits faint appear
ance Of tail Of several degrees in
length. The favorable position of this
comet Tor observation, will afford as
tronomers an unusual opportunity for
establishing or refuting some points in
relation to these bodies, not only inte-
resting in regard TO cometary bodies,
but also in connexion with phenomena
observed in the planets.
II has been stated by M. Valz and
others from observations made upon
Encke's comet, "that the real diameter
oil the nebulous part or body of the
comet, undergoes very sensible dimi-
mutton as II approaches the sun, and
an expansion as it recedes from that
body" and Nj. Valz has accounted for
this change in the size Of the diameter.
by supPosing real compression or
condensation Of volume, owing to the
pressure Of an ETHEREAL medium grow
ing more dense in the Suns neigh
borhood," while the present astronomer
Herchell suggests the possibility 'tha,
the change may consist in no real ex-
pansion or condensation Of volume
but rather that an increased portion OF
the matter Of the comet is rendered
perfectly transparent, and consequently
invisible by the increased heat arising
from its nearer approach TO the Sun,
and that this matter is rendered visible
again by condensation from cold, as
the comet recedes from that BODY
That the fact OF diminution in the
real diameter OF a comet on its increas.
ed proximity to the Sun will be veri-
fled by observation upon the present
comet, ! am fully satisfied, but it an.
pears TO me entirely evident that we
must look for the cause of this conden.
sation Of the matter in the comet, no,
to the causes here stated, but to the
combined influence Of the increased
centrifugal force Of the comet.
In confirmation Of the truth Of thi.
itmay be observed, that the planet.
with the exception of Uranus, the
great distance Of which from us ha.
prevented those accurate observation.
from being made that are necessary tc
determine its density with entire pre-.
cision) are known to be denser as they
are nearer to the Sun-Mercury is as
dense as Iron, while Saturn is MOI
halt as dense as water.-There can be
no doubt but that their dcnsities are
those that naturally result from their
situation. and that If Saturn be com.
posed of matter at all compressible
and could. like the comet, vary mate.
rally IN its distances from the Sun. II
would necessarily undergo changes in
its bulk, such as the comet of Encke
has been observed to do, and if com.
posed OF matter like the other planet.
it would acquire their dcnsitics as il
crossed their orbits, be n dense as the
Earth at the distance ofthe Earth from
the Sun, and as dense as Mercury al
the distance OF Mercury.
The present comet will afford an
unusually favorable opportunity fol
observation upon the subject, and
would respectfully call the attention OF
scientific observers 10 II.
BENJAMIN HALLOWELL.
.9Isrsaaria Boarding School.
l0th Ne. l2iA, 1895.