The native Virginian. [volume] (Orange Court House, Va.) 1867-187?, 1869-08-20
THE sPECTR0sC0PE.

Our readers, have seen great many
illusions to the spectroscope and its
marvellous revelations, but what it is
precisely and how its revelations are
made. few have been able even remote
ly to conjecture. The mystery is made
quite plain in the article below, which
those who have been puzzled will no
doubt thank us for publishing.
Spectrum Analysis. BY Henry E.
Roscoe. P. ii. D.. f. X. s. With col
ored Plates and Illustrations. D.
Appleton & Co.
The recent advance that has been
male in scientific progress is something
altogether astonishing.
70 70 department. of science does this
remark apply more pertinentiy than to
that NOW known Ms Spectrum Analysis. =
This research belongs entirely to the
present century, aid mainly to the
present decade. OF course we must go
hack to Newton for the spectrum itself,
bit the first step in this line OF its de-
velopment, was taken by DR.. Wollaston
III 1862. He discovered that If the field
,f the solar spectrum be closely OBJ
served with spy-glass, dark lilies iiiay
be seen crossing it; but he did not fol-
low up the subject. In 1914 Il German
obtit,sii. named Fraunhofe- gave atten-
ton to these spectral lines, and weiit so
far as to make a map OF them. The
next investigator " ho took up the sub
ject was DR.. John w. Draper of this
city. More than twenty-five years ago
he introduced into this country the
spectroscope of Fraunhofeg aud so
modified its construction as 10 impress
the fixed lines upoa "A sensitive chemical
surface and get Photographic Map OF
their distrlbltiol. He showed four
great groups OF these lines heyoId the
limit OF the violet ray, aud doubled the
number of them up to hat time known.
A bout the same time DR.. Draper pub
lished several papers on spectrum an
alysis. anticipating various things which
have been lately brought forward as
new.
But It was in 1859. just ten years ago:
that two German chemists. Bunsen and
Kirchoif, working together, took the
next important step that has become so
fruitful of recent results. They dis
covered that each chemical element.
when bufnlhg III a flame. emts n light
whic' when passed through prism
and forming spectrum, has lines or
marks peculiar to itself. These lines
iiiight be taken; therefore, as new pro-
perties of :he elements. aud could he
used To distinguish and detect them. 1t
is only in the condition OF uapor that the
elements produce the peculiar lines. If
platinum wire. a solid, he heated to
wliitensea, and its light passed through
Il prism; it gives continuous spectrum;
but II platlnttiii he vaporizel by the ell
ectic Current. ITS spectrum becomes
broken. and there is series ot bright
lines separated by varying insprvals of
darkness. II zinc he vaporizel. it gives
beautiful bands of red and blue. while
vapor Of sodium gives two fine yellow
lines situated close to each other. A
new and most delicate mode oi chemical
analysis was thus found. and the very
first result obtained bv it was the dis
covery of several hitherto unknown
chemical clements. Prof. Bunsen, in
examining the ash left after the evap-
oration of some mineral water. DIS
covered lines which did not appear to
belong to any known element. He then
boiled down Al tons o! this water. aud
from the mineral residue he extracted
two new metals resembling potash. one
of which he named Rubidiunl, because it |
gave dark red line, and the other
C'csimn, from its producing BLUSH
gray line.
The lines produced by the burning
vapors of the elements are varionsly
colorrd, but always bright, with dark
ut in the spectrum of the
sun and stars this is exactly reversed.
the lines being dark and the spices
bright. Kirchotf explained tliis beau-
tifu'y on the printiple Of absorption,
which we will try to illustrate. If we
20 iLto glass store with violin and
produce Il tone Ivy drawing the bow
ncross one of the strings, certain of :le
glass vessels will be set singing; they
will catch mp and give ont the same |
niusieal note which pre- eeeds from the
yioliu. But only thnse vessels sill do
this wlIitl are tiipable Or Vibrating In
unison With tie. striDg, or of giving out
the SAME note I HAT they receive. Ia this |
rase the souifd Of the strlhg il Said to bG |
absorbed hy the vessels which are capa- |
hle OF emitting only vibrations of the
same rate. Supposng now we have a
containing sodium yapor,
which gives the bright yellow lines in
its spectrum. If then we take an cleo
rrlc light. which il OF course very much
brighter. and containing also sodium
vapor, and let it shine through the can
die flame, the bright yellow lines do