The enquirer. [volume] (Richmond, Va.) 1804-1815, 1811-11-01
FOR TIE ENQUIRER.


to call eli him at Mr.. anderson Barrct's
FOR TIE E.hrQUIRER.
In my last, promised to make some re-
marks with respect to the elements of the
orbit OF the Comet. In the first place, how
ever, ! beg leave to correct a small error.
which arose in copying my nanuscr;,t.-in
the first line of the second paragraph in
place Of &C from SIN 10 2Ofh Oct3ber," read
from 5th 10 24tk Oct."
The only attempt which have seen 20
ascertain the elements of the orbit of yais
Come- has been by Mr.. Eowditch of Mass;.-
chusctts, according TO the method OF La
RACE have no doubt Mr.. Dowditch has
faithfully followed the. mode pointed out by
the French Astreusmcr. but the result he
has given only proves the uncertainty OF all
calculation with respect to Comets particn-
larry tie clements CT such, whose periods Ct
revolution arc unknown.
1 shall, therefore, with great d;ffidence Of
fer few observations upon those elements
furnished US by Mr. Bowditcli.
1st. The time OF the Comets passing the
Perihelion is made to DC the 9th of Septcm-
Der. -G
This seems impossible; for it is admitted
by all, that the light of the head of Comet
is greatest when in the Pcrihelion and that
1T decreases as it recedes from the Periheli-
on. Now the light of the head of the pre-
sent Comet has been increasing since first
seen. Within these last eight DAYS it is diff
ficult on account Of the moon light to know
whether the light OF the Comets head be at
present on the increase or decline.-It NAV,
however, be affirmed that the Comet had
not arrived at its Perihelion on the first Of
October.
I'd. MIR. Bowditch says the motion of the
Comet is retrogade.-l do not conceive how
he has fallen into this error; for the Comet
moves according to the order of the signs
with an increasing velocity since It's first APP
pearance.
3D. Mr.. Bowditch makes the inclination
OF lts orbit 74d.-According to my calculate
on it cannot exceed Gid.
4th. Mr.. Bowdith says the Comets least
distance from the earth is about 100 millions
OF miles. This is upon the supposition of the
Perhciion distance, and the time of the Co
NETS passing the Perilclion, which he has
given, being correct; but as it has been
shewn the Comet could not have passed the
Perihe!ion the 9th OF September, the distan-
ces which Mr.. Bowditch assigns must be cI>
roneous. From the great apparent magni-
tude of the Nucleus, which make I'm. SIS.
think it probable the Comets least distance
from the earth cannot exceed twenty MILL
onS of miles.
5th. MIR. Bowditch makes the orbit Of the
Comet to fall without the ilartli's orbit; but
considering the great splcndor of the Tan
and the Nucleus, think it much more pro
bable that it falls within the earth's orbit
by a careful comparison OF all the obsc;".a-
items which can be made during the period
the Comet IS visible, it may be possible TO
approximate to the elements Of It's orbit -
but any calculation at present OF this sort,
mus be extremely erroneous.
9th. With respect to the length of the
Tail, MIR. Bowditch Ibserves-'' The 1aH
0 the Conlct has been o6served to be- 10 or
IL degrees in ieng.h, 7vhich goouid make It's
real equal length 10 half the distance Of the
Earth jr9n the San
The data which MIR. Eowd;tch has assum-
ed will make the tail littc more than enc
fourth of the distance. For according to
Mr.. Dowditch, let the comets least distance
IRON the earth, be 40 millions CT miles, and
the tail 12d.-Ihe Suns mean distance rom
the earth is IS millions OF miles, his mean
apparent diameter 32m. and his mean diam
cter in:Englsh miles 8S3246-Thercfore if
the comet were at the same distance from
The earth as the sun, the apparent length OF
MS tail would be sd. 9m, or %. diane
tcrsequai to 25,084 1856 miles, little more than
IA OF the suns distance from the earth.
in my last number, gave an account of
the various theories which have been framed
to account for the singular phenomenon OF
the tails OF comets.---None of the celestial
phenomena have been less satisfactorily ex-
planned than this. | am still inclined to the
same opinion which expressed some wears
ago, that the tail is produced from an elonga-
ton OF the comets atmosphere OH the side
from the sUn,owing to an increase in the CEN
tirfuga force on tins side of the comet, upon
me hypothesis that comets have rotary
motion on an axis III Ike manner as the pla-
nc!s-Any increase Of the centrifugal force
must therefore have q consider able effect in
expanding an elastic fluid OF the extreme ra-
rity OK tie atmosphere which surrounds CO.
mc,s. This principie, have explained at
large, i'll my essay on the diurnai rotation vi
the Garth.
JOHN WOOD.