The Red Cloud chief., 1881-08-18

rs IL Tcctueu IN Snc SUD. lntEc "trc
thus two tails, nearly side b. side
stretching from opposite sides of the
sun in nearly the same direction. The
new tail began at the head OF the
comet; whereas the old deserted tail
began without any head 1T some dis
lance from the nucleus, and extended
further from the sun than the new tail.
The nucleus of the comet is surround
ed by a mist, which is called the conn,
or hair: the name comet s~ignifying a
hairy star. The height of the coma
above the nucleus depends on the mass
OF the nucleus, and gives the measure
OF its weight; or, more exactly, the
least limit OF weight which will suffice
to maintain such a heigh. of atmos-
! pherc. The nucleus is usually so close
" surrounded by the dense mist that
It's diameter cannot be measured; but
at times the mist rises, uncovcrs the
nucleus, and leaves it with a sharp
stellar aspect. The least diameter de-
termined at such times may be larger
than the actual one, but cannot be
smaller. From the combination OF mass
and diameter, the density of the nu-
| cleus can be computed. In the case of
DonatIs comet, the diameter OF the nu-
cleus was perhaps not more than a HUN
drcl miles, while the height of the at
mosphcre extended TO eighteen thou
sand miles. You may be surprised 10
learn that the corresponding density
of the nucleus was at least equal 10
that of iron. What an unexpected
/ contrast is here presented To the prev
alent notions concerning the sun and
the comets, The solid sun Is reduced
by science TO the state of gas, while the
substance Of the ethereal comet is asOl-
III and heavy metal.
In itS approach to the SIN, the sur
face OF the nucleus is rapidly heated; it
is melted and vaporizcd and subjected
to frequent explosions; the yapor rises
in its atmosphere with n wei defined
upper surface, which is known TO OBJ
4 servers a. an envelope. Various cnvel-
opes, including each other, are often
observed.
The electriiication of the cometary
mist is analogous to that of M own
thundercioud. ANY portion OF the
coma which has received the opposite
kind of electricity TO the sun and 10
the repealed tail viii be attracted. This
gives a simple explanation of the mega
tive tails which have been sometimes
seen, directed toward the sun. In cases
OF violent explosion, The whole nu-
cleus might be broken 10 pieces, and
the coma dashed around So rs Il give
varieties of tail, and even multiple
tails.
The relations OF the comets to the
solar system present an interesting and
instructive study. With very few ex,
ccptions, their visible paths are 50 III
" parabolic, and the positions of their
nuclei and centers Of gravity 20 uncer
tain in the midst of their come, that il
is quite out oI The question TO Obtain
nice enough data 10 measure exactly
the extent of their orbits, and ascertain
how great may be their d~eviatiOns from
exact parabolas. and whether the devi,
atoms are such rs 10 make them e!lipse.
or bvpcrbolas. If an orbit is actually
paraboiic or hyperbOlic, and if there i,
no decrease in the central attractive
force as the comet approaches the sun
il must have entered the solar s. stem
from outer space, and cannot be one @.
our permanent partners. 1t Will leave
the system again, and we may never
expect its return: unless, indeed, hay
inc passed through the circuit of otheI
suns, after myriIds of years, it reap
pears ia an orbit entirely different from
its former one, so as To afford no evi
dence through which it may be recog
nized. But fit moves liz an ellipse, anC
does not leave our system, ii will return
in 4 sensibly unchanged orbit, through
which ii may be detected
The astronomer is often asked, upOi
the announcement OF a comet, us it
new one?n and the tom of the inquirl
usually implies n feeling of Satisfaction
in witnessing the discovery of a new
star. But it is Just the reverse Within
astronomer himself. He raDsacks tn,
records. hoping against hope that h,
may eniov the good fortune of ascer
tanning that the new comet is an old on
old, at least. in the sense hat il ha
|, been observed once before, but no
: twice. On its first reappearauce
comet is certain TO be loaded with Thu
) name of the geometric G~iscoverer of il
!, path. Its theory is computed; lis futur,
returns are rigidly predicted; lis socia
IDSlllou Is uCtiillttiN tSldDllSutu, anu ]
: takes It's place among the regiStere.
) members of our constellation. But
: comet nav belong TO IL system. an,
vet 60 so far from the sun that the in
| tervals between its periods of visibilit
may be a long as three hundred thou
sand centuries.
/ There are a few comets of which tn,
nonparabolic character is evident a
once. Their orbits are decidedly elliptic
I al: their periods do noteXceed a baker
dozen of years; and they are intimatel
/; related to the plants in their position
and direction of motion. Prof. Newton
I of Yale College, has given a diStinc
/ and Satisfactory explanation o fthe mod
: in which these comets were probabl
t diverted from their original paraboli
paths by the action of the plane
; Jupiter. 1t was n royal sport. and tn
: final character of the cometary orb
/ was the natural termination of tn
: game. These comets must be exclude,
/ from u general discussion.
: Omitting them, we find nothing i
: the position of the other orbits whic
I indicates relation to the solar axis @
/ rotation or to the planetary planes Q
revolution. They are As uniformly dis
tributed as if they had entered on
system indifferently from every direc
, ton, and without reference to the pre-
vailing motion of the planets or TO thei
mutual organization. They are Simpl
' the largest of an immense swarm Q
4! meteors which are floating all aroun,
us--a swarm of which by far the greate
, portion consists of bodies too small TO b
seen BY the light thrown upon then
2 from the sun; and this invisible porto,
1 greatly surpasses, in number and eve
in combined mass. al the visible com
: ponents of our constellation.
Returning II the original round neb
: ula, from which the solar system wa
! formed, We must suppose that it ha
gone through changes which are repre-
scented in many OF the nebula. A cen
: trial spherical portion seems TO hav
concentrated into the sun and planets
: leaving an outer spherical envelope
which was much slower in the process
of condensation. and finally became a
3 envelope of bolides. The natural orbit
. of the bolides were nearly circu,a
: paths, of which the sun was al the cen
: ter. The variety of directions of tn
4 planes of the orbits was so great tha
j they constituted a nearly uniform sys