The Express.
London, England, 1858-09-28 00:00:00

(Stamped Id. Additional.)

orbits is that their calculation is far easier
than an elliptic one. Also, because the comet
can only be observed in that portion of
its orbit which is near the ran, it so happens that
if its elliptic orbit have any great degree of eccen-
tricity there is always a parabola, which will
ecaroely at all differ from that portion of its orbit.
Bucks observed that the calculated parabolic orbit of
the comet of 1818 was very similar in its elements
to those obtained for the comets observed in 1788,
1796, and 1805. It struck him that these comets
were identical ; he found more often that the calm-
laced parabolic orbit would not agree accurately with
the observed positions of the comet of 1819. He calcu-
lated the elliptic elements of the comet, and found that
its period of revolution was about three years and a
quarter. Mince then Enoke's comet has oome round
as regularly as any planet. It affords the astronomer
a means, by its slight deviations from its path, to
obtain a more exact knowledge of the mimes of Ju-
piter and Mercury.
known etaMakineaftanllowanoes for the re-
tarding effects of all ry influences, its
small variation from its related path has glean
rise to the suspicion of a resisting medium in the
interplanetary spaces, too minute in its retarding I
effects to be measured by any body less light and
coppery
In 1828 Biel* dissented the elliptic orbit of a
mast whoop period of tenrelatisn is six years and
Wes-quarters ; this is the coma which peened
througn our orbit in 1831. It is moat remarkable is

pointed out by theory sad oakulation. On the 79th
of December it seemed to shoot out a tail towards
the sun, instead of from it, according to the general
disposition of oometary tails. In this anomalous
tail a knot seemed to form of a brighter and more
oondensed kind of light. After a few days this
knot seemed to grow more distinct, and the comet
war converted into two comets, a larger and a
smaller, both nearly round, travelling through space
together. This double comet has still retained its
compound character in its visitations when observed'
both at Rome and Cambridge in 1832. On this
occasion it was so faint that it was only observed
nine times.

This extraordinary behaviour of Biela's comet
renders the gee-light jet thrown out by Donati's
comet, u described by Mr. Hied on the 13th of this
month, a subject of intense interest to astronomers.
On the whole, reviewing all that is certainly
known of these beautiful and interesting visitants of
our portion of the universe, we see in them no cause
of dread. We fear no collision ;we dread no deluge.
With Sir Isaac Newton, we would regard them
rather as beneficent than injurious visitors. Re
speculates that their use may be to replenish the
atmospheres of both the sun and planets with
useful elements. The aerates which oteasionally
fall from the heavens to the earth supply the chemist
with no new elements. These solid muses of matter
revolving round our central sun, and crossing our
path so as to come within the range of our atmo-
sphere, are composed of the same elements
es terrestrial bodies. This would lead us
to infer that the matter of the solar system is
the same throughout its various members.
We may therefore anticipate that the elementary
vapours of comets are similar to our own, and might
therefore mix with our own atmosphere, if not with
advantage at least without inconvenience. Fruit-
ful harvests and vintages accompanying remarkable
manifestations of comets have caused them to be
looked on with favour by the vulgar. These may
not be simple coincidences. The forces which cause
=meta to split in two and to alter the shape of their
tails, imply the existence of each forces as those of
electricity and magnets= in great power and action.
For aught we know they may influence the sun, if not
by an addition to his atmosphere, at all events by some
change in the active powers of his heat-and-light
evolving capacities. If the sun spots have some
mysterious oonnexion with magnetic earth storms,
and if these be in some way related with our seam=
and their fruitfulness, science may yet discover that
comets have a beneficent influence on the earth.