, 1877-08-31
The Dumb. Bell Nebula.


In Vulpecula there is remarkable OBJ
jsct called the Dumb-bel nebula, or star
cloud. 1t cannot be seen well without
a very powerful telescope. 1t was for
merly thought to consist entirely of small
stars, so remote that they could not be
separately discerned; but it has lately
been discovered that the greater part of
this nebulas light comes from glowing
gas. The vastness of the space occu-
pied by this cloud of luminous gas will
be understood--though no mind can pos
| sibly conceive it-when | mention that
at the distance of the nearest of the fixed
stars the whole Of our solar system would
appear but as q mere point, even in Il
powerful telescope. The Dumb-bell
nebula covers quite large space, as seen
in such an instrument. 1t is also, prob
ably, much farther away than the near
est fixed stars. 1t must, therefore, occu-
py region Of space exceeding many
times that through which the planets Of
our solar system pursue their paths. Yet
the span of our earth's path around the
sun is fully one hundred and eighty-four
millions Of miles, while Neptune-the
remotest planet of the solar SYSTEM
travels thirty times farther from the sun,
having thus an orbit spanning more than
five thousand millions of miles. A globe
just fitting the path of Neptune would
contain many quadrillions of cubic miles
and probably the Dumb-bell nebula ex-
ceeds such aglobe in volume Cor, to speak
more exactly, occupies a space exceeding
such a globe in volume) many millions
of times.
Very strange is the thought that as
tronomers should have been able to find
out what this mighty mass of glowing
gas consists Of, Placed yonder amid
the glories of the Milky Way, lost to hu
man vision through its vast remoteness,
only brought within our view at all by
means of powerful telescopes, and only
revealing its true shape when seen with
the most powerful telescopes men have
yet constructed, what at first sight can
seem more amazing than that men should
be able to tell what kind of substance it
is which gives out the mighty lustre of
that cloudlet in spacel The very light
which comes to US from the Dumb bell
nebula has probably taken hundreds of
years in crossing the tremendous space
separating us from that object. Yet that
light has conveyed its message truly.
Examined with that instrument the spec
troscope-whose office lately described
in paper on the planet Venus--the
| light Of the Dumb-bell nebula presents,
not the rainbow-tinted streak which
comes from glowing solid and liquid
bodies, but three bright lights only. At
least three lines are seen if the nebula is
examined through fine slit; if the field
of view is opened, there are seen three
faint images of the coudlet. The cor
rect way of describing what the spectre
scope tells US about this object is to say
that, instead Of its light presenting all
the coors of the rainbow, it is found,
when sifted by the spectroscope, to con-
tain three colors only, all of them green
ish, but slightly different in tint. One of
the colors is precisely sucha tint of green
as comes with four other colOrs) from
glowing hydrogen gas, and shows us that
there are enormous masses of hydrogen
in that remote cloud; another tint shows,
in like manner, that there are immense
masses of nitrogen; but the third tint has
not yet been found to correspond with a
tint emitted by any known substance
The skein of light from that double fluff
ball has thus been unraveled by the spec
trOscope, after journeyiug millions OF
millions of miles, and has been sorted
into three tints, two Of which have been
matched against the known tints of earth.
ly gases, but the third remains as yet
unmatched.-Pr0f r. A. Proctor, in So
Nicholas.