Juniata sentinel and Republican. [volume] (Mifflintown, Juniata County, Pa.) 1873-1955, 1877-09-26
The spectroscope in Astronomy.

The clusters of matter which are
called nebuls, snd which the most
powerful telescopes have resolved into
stars, are shown by the prism to be
nothing but patches of luminous gas,
possibly the first beginnings of un-
created worlds. Comet-tails are of the
same nature, doubt existing as TO
whether their nuclei borrow their light
from the sun or emit light of them
selves. We may close a necessarily
brief outline on this part of our subject
by stating that it is possible that the
spectroscope may some day snpplant
the barometer, more than one observer
having stated that he has discovered by
its aid signs of coming rain, when the
latter instrument told a hattering tale
of continued fine weather.
We have merely shown hitherto how
the spectroscope is capable of identify
ing a metal; but its powers are not
limited to this; for by careful mea-
surement of the length of the absorp-
ton lines, a very exact estimate of the
quantity presented can be arrived at.
This method of analysis is so delicate,
that in experiments carried on at the
Royel Mint, a difference of one ten
thousandth part in an alloy has been
recognized. Neither must it be sup
posed thas the services of the spectre
scope are confined to metals, for nearly
all colored matter can also be subjected
TO its scrutiny. Even the most minute
substances when examined by the mi
eroscope in conjunction with the prism
show particular spectrum by which
they can always be identified. Nor
does the form of the substance present
any difficulty in its examination, for a
solution will show the necessary absorp-
ton bands. Blood, for instance, can be
discovered when in a most diluted
form. To the physician the detection
of the vital fluid in any of the secre-
tiOns Is obviously great help to the
diagnosis of an obscure case. But in
forensic medicine (where il might be
assumed that this test might be of
value in the detection of crime) the mi
croscope can identify blood stains in
more ready manner.
The simple glass prism, as used by
Newton, although it is the parent of
the modern spectroscope bears very lit
tie resemblance to its gifted successor.
The complicated and costly instrument
now used consists of train of several
prisms, through which the ray of light
under examination can be passed By re-
feetion more than once. By these
means greater dispersion is gained; that
is to say, the resulting spectrum is
longer, and consequently far easier of
examination. A detailed description
of the instrument would be impossible
without diagrams, but enough has been
said to enable the reader to understand
theoretically its construction and appli-
cation
1t will be understood that we have
but lightly touched upon a phase of
science which is at present quite in its
infancy. 1t is probable that many
more remarkable discoveries will in |
course of time be due TO the prism. |
Already within the past twenty years, T.
four new metals have by its aid been |
separated from the substances with Z
which they were before confounded; /
and although they have not at present /
any commercial value, we may feel sure |
that they have been created for some |
good purpose not yet revealed 10 us. /
There are signs that the spectroscope |
will some day become a recognized ad- 1
junct 10 our educational appliances. 1t 1
is even now included under the head of /
chemistry in the examination of candi- ,
dates for university honCrs, and there .
is no doubt that it will gradually have
q more extended use. Many years
hence, when generations of school
boards have banished ignorance from
the land, the speclroscope may become
a common toy in the hands of children,
them TO lisp:
Twinkle. twinkle little star,
We know exactly where you are.
Chambers Journal