The Burlington weekly hawk-eye., 1862-11-15
The Nebul9.

OAAuEOnI, D. " OcL. Il, lCOA.
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The NebuIe:
From the Boston Courier.
The science of astronomy is everywhere
marked in its progress by we'll defined epochs.
Discoveries of new physical phenomena in the
celestial spaces or new laws regulating
the movements and changes there going for-
ward, are often Of such magnitude and impor-
tance as to add new and interesting branch
to the science Old phenomena when submit.
ted anew to the refnements of modern obser>
vation-to the increased power of the teles-
cope, the more delicate means of measurement,
and the more persistent scrutiny of astrono-
mers-yield new phenomena, which are either
incidental to the old or principal and depend
for their apparent connection upon mere jux-
Imposition.
That class of heavenly bodies known under
the appellation of nebula, has been for more
than century past one of very general inter-
est. These objects gave rise to the sublime
speculaticns of La Place and the elder Hershel,
on the cosmogony of the universe. The "neb-
lar hypothesis" Of La Place has been discussed
by more learning and ability than perhaps
any cosmogony theory of modern times. 1t
had the great merit of being comprehensive,
embracing every variety Of planetary phenom.
ena, so far as relates to motion. But the pow
ers of the telescope have almost dissipated all
the nebule of the heavens. In most instances
these masses of apparently chaotic matter
have been discovered to be nothing but swarms
of stars, so crowded together as not to be dis.
tinguishable except with very large telescopes.
Although there still exist objects which ap-
pear as nebul@ in the most powerful telescopes
hitherto constructed, yet it may we'll be con-
sidered as certain that with still more power
full telescopes they too may be resolved into in
dividual stars.
The nebul@ for ages have been regarded as
having at least three characteristics in cons
mon with fixed stars-a permanency Of form
and position and position in space, and uni-
formity Of brilliancy. Nothing was, therefore
more unlocked for ard startling than the an
nouncement last year, by D'Arrest of Copen-
hagen, that nebula discovery by Hind of
London, in 1852, had disappeared altogether.
Subsequently he announced that q nebula, dis
covered by Tempel had shared the same fate
and few weeks ago he declared that nebula
discovered by Tuttle in 1859, at Cambridge,
had become SO reduced that it was but Just
visible il his telescope. These three instances
Of change of brilliancy are thus we'll estab>
lished. That they are periodical changes,
would seem to be the fact from the reappear-
ance of the Hind nsbula, not long since $500
A few Of the stars have been ascertained to
be variable in lustre' but that whole stellar
swarm should at once become visible, is
truly astonishing Further observation will
be necessary before any propable explanation
of this phenomenon can be hazarded. Such
new and striking feature in this class of bodies
forms an important epoch in their history, and
it will be watched by astronomers with a zeal
hardly ever before devoted to any new pine
nomenon, and by the public with that curious
interest which attaches itself to the nebnlar
hypothesis.