Mississippi Democrat. (Carrollton, Miss.) 1844-18??, 1845-01-22
atsreIIamp.
DR.. LARDNER's LECTURES.
TIE COMETS.

DIR. Lardner introduced his subject with
a few remarks on the character of the
planets, with the view of subsequent com
parison with the motion of comets. He
adverted to the circular orbit of the plans
els, and the fact that that orbit was upon
an inyariable plane, from which there was
no deviation, and thus they maintained
uniform position with regard to the sun.
The comets also revolve round the sun,
attributable entirely to the power of the
suns attraction. In this respect, they
agree with The planets, and thus establish
the fact that they belong to The solar sys-
tenn. But in every other respect they diff
fer. In the first place, they do not revolve
in circles; their path is oblong, or what is
familiarly called an oval, and the position
of the sun, instead of being in the centre,
It's relative position to the orbit of the
planets, is at one end of the oval path of
the comets. Thus we have the evidence
that the comet is at various times at very
different distances from the sun, being
sometimes more remote than any planet
in our system, and at others in the imme
date vicinity of the sun; indeed there
have been instances in which the comet
has come into actual contact with the sun
-grazed the surface of the sun, so to
speak, as was in fact the case with the
comet of March, 18I3-last year. The
planets we have seen move in the same
undertaking plane, which may be indica.
ted by the motion of the hands of watch.
Such is not the case with the comets.-
They move in every conceivable angle
with the plane of the ecIiptic some NOV
ing directly perpendicular with il, others
at an angle OK 45o, and indeed at every
possible angle of the scale; it has also
been demonstrated that there are exactly
an equal number moving at one angle that
there are at another; thus the same num-
Der move at an angle of 400 that have an
angle of 45o, and so on. Their motion
is also irregular in another important par
ticular: they have by no means the uni
form direct or forward motion of the plan.
cts; some move forward and some. have a
backward-or as it is scientifically. called
"a retrogade motion, and Arrago has de.
termined that the number of those which
move backwards is precisely equal to those
which move forwards. In short, these DO,
dies exhibit the most sovereign contempt
for all the known laws Of motion, or ra-
Their in their motion obscure the letter 81
the law, but holdin utter contempt the
spirit Of it. With another allusion to Ar,
rrago, DR.. Lafdner paid a high tribute to
MS talents, assiduity, and the eminently
successful and gratifying result Of his Ia.
Dors. Arrago, said the lecturer, has inst.
lulea an ingenious investigation with re-
gard 10 the number Of comets He asks
the question, how many are probably at.
tached 70 our systemg If we imagine 4
space described by the orbit Of Mercury,
which Is the planet nearest 10 the sur. and
another distinct thercfrom living between
the orbit Of Mercury and the orbit 81
Herscheb the remotest planet of onr svs.
tenn, we shall find upon the measurement
of each space, that the proportion &c Ina
included within the orbit Of Mercnrv
bears a proportion 10 the space witbo,1
that orbitand within the orbit of IIerscbet
including of course the whole intcrne,3ii f.
ate space occupied BIZ All The Other 81 anets
as | 70 $4,000. Nov he comets raa j
throughout The system pretty uniformly
being distributed apparently equally Il
every part; and for every single come
therefore which has It's perlheli0n ia nIcr