The daily exchange. [volume] (Baltimore, Md.) 1858-1861, 1858-10-04
TIE COMET, AS SEEN BY PROF. MITCHELL,
THE ASTpONOMEp

Professor Mitchell, of the Cincinnati Observa-
tory, has been observing the comet, and he gives
the following description of it. He says it has
been steadily approaching the earth, and in a di-
reCtiOn so nearly cOincident with the visual raw
that but for the reliable computations of astrono-
mciS, might well excite anticipation of some fear
full collision with our planet. Indeed through
out the present month, it seems to have been pung-
ing downward so exactly toward the earth that it
scarcely changed its apparent place among the
fixed stars by quantity larger than two or
three times the apparent diameter of the moon.
twill reach its nearest approach to the sun in
a few days. Its brilliancy will increase rapidly up
to the close of the first week in October when it
will put on its most splendid appearance, and will
then rival in grandeur the famous comet of HALEY
at its last return in 1886. The comet will soon
commence to change direction, at first slowly after
ward more rapidly, from the earth, when
sweeping swiftly round the sun it will regain those
distant regions OF space wherein a vast proportion
of its orbit lies far beyond the reach of telescope
vision.
On the evening of the 25th of September the
appearance of the comet in the great retractor of
the Cincinnati Observatory, was especially inter
esting. The central portion, or nucleus, was ex-
amned with powers varying from one hundred
to five hundred without presenting any evidence
of well-deiined planetary disc. 1t brilliant
glow of light, dartng and flashing forward in the
direction of the motion toward the sun, and leaving
the region behind in comparative obscurity. But
the most wonderful physical feature presented was
a portion Of Il ncoriy crcaiar RebH0Hs ring with
its vortex directed toward the sun, the bright
nucleus DclnG IN the centre, Wnlle the imperfect
ring swept than half way round the
luminous cetre. This nebulous ring reSembled
those which sometimes escape from a steam pipe
and did not exhibit the appearance which ought to
be presented by hollow hcmisphcrical envelope
Of nebuous matter There an evident concen-
traton Of light in the central portions of the ring
while, in the case of hollow envelope, the bright
est portion should be at the outer edge. By micro
metrcal measurement the distance from the central
point to the circumference of the ring was about
5000 miles. This would give diameter of 5000
miles in case the ring entire. Similar meas
urements, made on the evening of the 26th of Sep
tember, indicated decided increase in the radius
of the ring, which now not less than twelve
thousand miles in length.
On the same evening | noticed the fact that the
luminous envelope did not blend itself into the
head portion of the tall but appeared somewhat to
penetrate into this nebuOus mass especially on the
upper part, presenting the appearance of about 200
degrees of a spiral. The tail on the 25th was de
cidedly brighter ard better defined ON the upper
than on the lower portion, while on the evening OF
the 10Th there was much nearer approach to
equality in brightness especially near the head Of
the comet Through the telescope, and near the
head, the tail presented the appearance of hollow
nebulous envelope, under the form of paraboloid
OF revolution, the edges been brightest and well de
hned, while there was manifest fading away oi
light toward the central region. Through the vast
depth OF nebulous matter composing this wonderful
appendage, the fantest telescope stars shone with
undiminished brightness.