The Nevada Democrat., 1861-08-10
From the Scientific AmerIcan.l
The Mystery of Comets Tails.


There is nothing III nature more mysteri-
ous than the growth and motion OF the
trains OF comets. When comet is first dis
covered by a telescope il generally has no
tail, appearing like faint star thrOuah
haze. AS it approaches the sun the tail IL
developed, starting out at the side next to
the sun, but being Immediately turned back
rs if it were u flame acted Oh by powerful
blast coming from the sun. Tue nucleus or
head of the comet is matter, though lighter
than the thinnest fog, but the tail is ether
not matter at all, or is acted on by forces
which do not manifest themselves on THIS
earth. II The train were simply matter, ac.
ted on 10y gravitatiOn, it would follow the
head in its track around the snn, cOnse
dnently bending, as the head sweeps around
the part of its orbit nearest the SUI, into
nearly q semicircular curve. Instead Of this
the train always points from tue sun, swing
ing around as the stream Of light from lau-
tern in the fog does when the lantern is
turned. As the trains are sometimes OF
such length that they would reach fl ON the
eun to the earth, aud as the comet when
nearest the sun moves through many de-
grees of its orbit in few hours, the end OF
The train is swept around with velocity
which fOrbids the belief of its being matter
possessed with The property of inertia.
The velocity, too, with which the tail is
shot forth is irrecOnclable with the idea Of
its being subject to the law of inertia. The
tail of the great comet of 1850, immedi-
ately after its perhelion passage, was found
by Newton TO have been no less than sixty
millio8s of miles in length, aud to have oc-
Cupied oUly two days in its emission from
the comets body.
One of the most singular phenomena of
comets tails is the violent commotOn OBJ.
served in them. Flames stream fOI Ith from
the nucleus in fan.shaped aud variOno other
and swiftly changing forms, toward the sun
at first, but bending quickly back as il en-
countered by furious blast, and then
streaming away millions of miles into the
Ky. This may be owing TO the intense
heat to which they are exposed from their
proximity to the sun. The great comet Of
1843 approached the sun within about
seventh part of the suns radius. Sir John
Herschel calcniates that at this distance the
heat of the sun would be AZ 042 times
greater than it is al this earth. aud at least
24h times greater than the heat in the fOcns
of Parker's great lens which melted COR
nelian, agate and rock crystal.
Usually, as the comet moves away from
the sun, the train, which it is now pushing
partly before il, adually diminishes till it
disappears altogether. Sometimes. however,
the train is ObIileTated in the vicinity of the
sun, the comet emerging from the SUMS
light without any tail whatever. At other
times the tail is the longest just after the
perhelion passage; at others there are two
or three or more tails branching out like a
fan. They are frequently curved like Do
MATHS in 1858, aud exhibit great variety
of singular phenomena; which are an in
comprehensive mystery to the students of
astron Omy.
At about the same time, Bsse and Prof.
Pierce, each independently of the other, Of
fered the suggestion that the trains of COM
cts may be electricity. Perhaps they are
simply light; the suns rays in their passage
through the unknown substance of the
nucleus, may acquire the pOwer-analogous
to polarizaliOn-of producing the vibra.
tiOns which constitute light.
The heads of comets are unquestonaby
formed of material substance, as they are
acted on by gravitation, and reflect the
SUMS light, but this substance is generally
of extreme tenuity. Stars of the smallest
magnitude have been seen through the
densest portion of the head, and, in the Ian
guage of Sir John Herschel. "The most un-
substantial clouds which float in the highest
regions of our atmosphere must be looked
upon as dense and massive bodies compal ed
with the 6lmy and all but spiritual texture
of a comet" In some, however, very
minute stellar point has been seen, Indica-
ting the existence of solid body.
Among the mysterious phenomena pre-.
sented by the head, is its diminntion in size
as it appr caches the sun. and its rexpansion
during its retreat. 1t also throws of neb-
ulOus envelopes one after another, during
the formation of the train. in very curious
manner.
Many of the comets move in eliptical or
bits, and continue to revolve arOnnd the
Sun. But the orbits Of few have been as
certained to be hyperbolas, aud these con.
sequently will never return. Light, ethe-
real volumes of vapOr, they come from un
measured distances above, below, or on