Nashville patriot. [volume] (Nashville, Tenn.) 1858-1860, 1858-10-18

COMMUNICATION FROM Mr.. BOND, OF THE Hal
WARD OBSERVATORY

WARD OBSERVATORY.
There are several distinctive features in the
imposing spectacle of the great comet now
attracting universal attention, which can
scarcely have escaped the notice of even the
most casual observer. We have first the ma
jestic sweep of the train; not projected in
straight line from the head or nucleus. but in
curve of stuprndous proportions, reaching
far up towards the polar circle. Another
popularity is the regular contour of its upper
or convex side; the lower side, on the contra
ry. has an ill-defined and uncertain outline
The upper edge is also plainly the brightest
through its whole extent. The star. like con-
centration of light in the head. and its grad
ual elimination. until it is lost in diffused
light on the dark background of the sky, are
other interesting phenomena. These are all
prominent features, scarcely requiring an
effort of attention to recognise them.
There are Others not so strongly marked.
but yet easily detected hya good eye without
telescope aid. There is. for instance. de-
cided but very narrow dark streak near the
middle of the brightest part of the train, lead
ing quite up to the nucleus.
Again, by careful watching. one or more
supplementary tails or faint rays can be seen
diverging near the nucleus from the main
stream of light on its upper or convex side
and extending for fifty or sixty degrees.
These have a considerably less curvature than
the principal tail. and diverge long distance
from it at their extremity.
When it is considered that the field of view
of a powerful telescope is necessarily limited
to an area of less than a thousandth part of
the portion of the heaven occupied by the
comet, it will at once appear why its aspect,
through such an instrument. commonly dis
appoints the expectation of unpractised OBJ
servers. The grand characteristics above emu
mcrated are, for the most part lost. and they
see only star shining through dim envelopes
of haze, and encircled with misty halOs. The
astronomer however will be far from sharing
in the disappointment.
Since the 18th of June the present comet
has been constantly watched with the great
refractor of the Observatory of Harvard Col
lege. The extraordinary phenomena devel-
oped during this period, in the nucleus and
surrounding region, have scarcely been paral-
leled in astronomical history.
For many week ks succeeding its first discovery
the comet exhibited an appearance not un-
common in bodies of its class, excepting the
single fact of its being visible at all from the
immense distance of more than two hundred
millions of miles at which it was placed from
the earth. 1t was a mass of faint ditiused
nebulOsity surrounding starlike centre. far
beyond the reach ofany but superior telescope
vision.
In perfect accordance with its predicted
course ii continued to increase i'll brightness,
and on the 10Th of July it already surpassed
the average of telescope comets, but the first
traces of a tail were not noticed until the goth
of August. On the 29th it was visible to the
naked eye. and train of two degrees in
length could be discerned in the comet seeker.
The intense central light at this time was
about five thousand miles in diameter.
The curvature of the tail was noticed on
the morning of the 9th of September. 1t is
highly probable from this observation that
the plane of curvature does not lie in the
plane of the orbit. as has commonly been
supposed for had this been the case. from the
position of the earth at that date, being close
TO the line of nodes, the tail ought to have
been sent straight.
On the goth the first of a series of extra
ordinary phenomena manifested itself in the
region contiguous to the nucleus. A crescent
shaped outline, obscure and very narrow, was
interpOsed, like screen betweed the nucleus
and the sun; within this, instead of softly
blended nebulous light Indicative OF an
undisturbed condition of equilibrium. the
fiery was in state of apparent cOmmO-
ton. as though upheavcd by the action of
violent internal forces. On the 23d two
dark outlines were traced more than half
way round the nucleus. and on the next even
ing still another. Each of these was evident
ly the outer boundary ola luminous envelope
the brightest being that nearest the nucleus.
On the 25th four envelopes We're seen, and
others have subsequently been formed,
almost under the eye of the observer. their
motion of projection from the nucleus being
evident from night to night The rapidty of
their formation, and the enormous extent to |
which they are ultimately expanded, are
phenomena extremely difficult to explain
The scene of chaotic confusion presented |
within the inmost envelope can only be
for the result of sudden and |
violent disruption from the central body, |
projecting immense volumes of its luminous !
substance towards the sun, which by some |
unknown law, is in turn repealed 10y that |
body and driven off to the distant regions of
space. forming the vast train of light SO
Of these mysterious bodies.
1t is probable that the comet has now passed |
is maximum of brightness, although the
englh Of the tail may be on the increase for
some days to come. Whether we are yet to
witness the inverse operation of the recon
'truction of tbs nucleus by the subsistence of
the envelopes and of the material of the tail.
Ipon it, or whether it is incapable of restora-
ion to its original condition are interesting
subjects of speculation; the latter, however
would seem to be the most likely of the two
alternatives.
HARVARD COLLEGE OBSERVATORY Oct. s, 1858.