The Caledonian. [volume] (St. Johnsbury, Vt.) 1837-1867, 1858-10-16
Tho Comet.

Professor O, VI. Mitchell Of the Cincinnati
Observatory communicates 20 the Cincinnati
UIZ5uc-H vrry interesting account 0f thr
comet which is now the object Of 30 much in
tcrcst. lie says;
This remarkable object now presents a
most striking appearance among the celestial
host la misty grandeur IL even holds high
rank among that class pf heavenly bodies TO
which u belongs IL was discovered by Pro-
fcssur Donati Of Florence. Italy. nearly four
months since, and for a large part of the time
since j, was detected, has been steadily up.
preaching the earth, and IN - direction 80
nearly coiucidcnt with lllr visual ray that
but for the reliable computations Of nstrono-
mrrs, might wcil excite uutiCipations OF some
fearful collision with our own planet. In.
decd, throughout the present month IL seems
10 have been pluuging downward 80 exactly
toward the earth that il has scarcely chang
cd It's apparent place among the liked stnrs
10y quantity larger than two or three times
the apparent diameter of the moon.
On the 18th Of September the appearances
OF the comet, IN the great rclractor of the
Cincinnati Observatory, was especially inter
cstiug. The ccutral portion, or nucleus. Was
examined with powers varying from one hun.
drcd 10 five hundred, without presenting any
evidence OF a.wcll defined planetary disc. 1t
was brilliant glow of light, dartng and
flashing forward IN the direction of the mo.
ton toward the sun, and leaving the region
Lrhllll li4 h..ita.ttfiisr HAT tire
most wonderful physical feature presented
was portion of nearly circular, nchulous
ring, with its vortex directed toward the sun,
the bright nucleus being in the centre, while
the imperfect ring swept more than half way
round The luminous centre. This ncbuluus
ing rcscmblcd those which SOME times escape
from steam pipe, and did not exhibit the
appearance which ought TO be presented by a
hollow hcmNphcriclI enycop of ncbulous
matter. There was an evident concentration
of light IN the central portions OF the ring,
while IN the case of hollow enveop the
brightest portion should be at the outer
edge. by micrometical mcasurment the
distance from the central point TO the cir.
cumicrencc of the ring was found to be
about 5000 miles. This would give diam
ctcr of eighteen thousand miles, in case the
ring was entire. Simiiar measurements
made on the evening of the 2jth of Septcn,-
Der indicated decided increase in the radius
ct the ring which was now not less than
twelve thousand miles in length
On the same evening noticed the fact that
the luminous cnyelop did not blend itself in
to the head portion of the tail, but appeared
somewhat 10 penetrate into this ncbulous
mass, especially on the upper part, presenting
the appearance of about 200 degrees of n
spiral. The tail on the 25th, was decidedly
brighter and 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 Throdgh the telescope
aud near the head, iho tail presented the aIi-
pearancc of hollow ncbulous envelop, under
the form of a parabaloid of revolution, the
edges being brightest and well defined, while
there was a,manifest fading away of light to-
ward the central region, Through the vast
depth of nchulous matter composing this
wonderful appendagc the faintcsi telescopic /
stars shown with undiminished brightness.
The only comet which has presented an
appearance resembling the one now visible,
is the one known as Haley's comet, Ms seen
by Sir William Herschel and others, in it's
return in 1886. There is this marked differ
cnee between the two that while the cnycl-
op of Halley's comet is described as hcmis-
pherica hollow envclop, this shows more the
shape of n ncbulous ring; there is 4 faint,
misty light of irregular ont line, but. not to be
mistaken by even "A casual observer.