New-York daily tribune., 1858-10-15

emerge from tue dcpths of space, are nothing but
mere specs Of nebulosiy which is gradually prolonged
INTO train as they approach the sun il was Inferred
that comets are, in their normal condition spherical
masSes, Ike planets, aad that their tails are due, in
some unknown way, TO the sun. Some early
ob-ervers supposed the tail owing TO the passage
OF the suns rays through the nebulo-ty Of the head
producing an effect similar 10 what Is when a
beam Of the sun pours through an aperture into a
dsrkened room. Tie Carte-an school referred the
effect to tie reiracon OF light, IN Is passage !om the
comet to the eye Of the Observer, through the cees-
tal ether disseminated through space. II this theory
D. true il has been significantly asked, why have The
planets and fl Ked star, tails Marian thought the
effect proceeded from the cause 81 shs. which
produces the aurora boreaiis.
Tie lustrious astronomer, Kspler, who fonr-hed
early in the sever teenth century the first TO oer
a rational explanation of this phcnomenon He sup-
posed that the constituent matter Of the comet ~
broken by the action Of the solar rays and tie lighter
particles impelled to immense distances. Newton
jectured thst, Tie nebnous PARTICLES oil the comet
become heated by the sun, they communicate pur-
ton of their heat TO the contiguous particles Of ee
rial aGid composing The suos atmosphere These
particles go heated by reflection as il were suffer
corresponding dmnution Of density, and are repelled
from the SIM, carrying with them the more volatile
particles OF the cometai, body just upward cur
rent Of air smoke to ascend. But all hypothc-
ses must be vague where there so few wcasoer-
tanned data. The great discoveries made Of late in
electrical iorccs promise to throw light upon this
profoundly interesting subject.
The Close approach Of some comets to the sun in
their pcrhelion passage, as, for example, in the case
si the gre.. comet of 1913 before mentioned and the
immense distances 10 which they sometimes recedc
from him in their ophelis, inmessurably beyond the
utmost known limits Of our solar system, have led
astronomers TO infer that comets subjected in the
course Of their orbtsl revolution to an amazing de-
gree Of best and cold
Newton calculated that the comet OF 1850 was sub
jscted, at s perhcon dstancc Of $50 GD0 miles, TO
degree Of heat ., 600 times that of relhot iron
While according to Iierschel, the comet of 1913,
which passed within 9G A0 miles of the sun received
at its periheion amount of heat equivalent TO that
of IL, 900 suns blazing in our sky II scarcely be
supposed that matter can be subjected to such de-
gree OF heat without having its STRUCTURE destroyed.
Laplace avaed himself of Blacks beautiful discovery
of latent heat to avoid this difficulty aud taught that
when u body is pessng from liquid to gaseous
state s particles, they become succeSsivoly vola
tilted, abstract from the body large quantities of
calorc and serve to moderate the temperature of
the condensed portion and, conversely, that this
latent caOrc is given back by the voatlized matter
in the of It's return TO liquid state SO that
comet, whether swinging in its orbit few thousands
OF miles from its local source of heat and attraction
many thousands of millions OF miles distant may pre-
approximate constancy Of temperature under
the operation Of this beautiful law Of compensation.
Astronomers often differ widely in their calculations
of comet npon its first appearance; and as, accord
ing to Prof Norton not than one.haf Of all the
comets which recorded TO have appeared during the
last two thousand years have returned twice to their
peihelia il must be admitted tlat the amount of we'll
digested knowledge of their motions and physical
stulon be but small. This much, however, seems
TO be conceded-that they have atmosphere, in
which the nebulous matter of them floats clouds do
in ours; that the aggregate amount Of matter they
contain, compared with the least Of the heavenly
bodies known to u.s. is exceedingly small; that the
tail is constituted Of the subtes portions Of the cometc
matter difused by solar agency that their orbits
parabolic elpses of great eccentrcity; that they
are liable to great changes in their periods of revolu
tion, being sometimes made to revolve in orbits
with quickened retarded notion Wy the attraction
OF foreign bodies into whose neighborhood they may
pass in the of their eccentric career and thus
that of the thousands of comets which supposed to
have for focus all, except the half dozen of
shor, periods must eude the grasp of human cal
cuations; and, finally, that some have appeared
which will not probably ever revisit our earth Well
may we say, with the sweet Psamist of Israeli
Whittier shall go from Thy spirit whittier shall flee
from Thy presence If ascend into heaven Thou art
there; if make my bed iu hell behold Thou srt there. If
the wings Of the morning ard dwell in the
the there shall Thy hand lead and Thy right
hand shall hold me"