New-York tribune., 1873-01-25

ITe above cut is horizontal section o. the spectre
scope employed by Prof. Young. The light enters
,iuough a oomatOr below the telescope IN the hgufe'
falls the prsms at A. and is thence reracted around
lob this prism it Is refTaced back through the
upper parts prisms in the figure and finally passes
through the telescope 10 an eyepeoe beyond "here
fbe light may be examined.J
For use with the telescope We must have many
yTisms Here is diagram Of The instruments @ Hloh
lies the colliInator. The light goes through
the oomator then passes through the nrse sera nS m
means Of totally rejecting PRISM IT IL transferred 20
the second story OF The pslns when are la tb ~
iow them 20 be called twostory prislns passed @
Them again. and then back into the telescope 1ou VIII
notice thai in so DONG the hglt passes UHgn eo tcI
prisns twice giving II an extension OF c0oi equai 10 yen
pr,sms aud beside that there are two half prsDsi SO
That dispersive power of the whole combination II
represented. We bring any particular part OF TINS spec
fIm which wish 10 examine into the HELD, by turn
lnc h- screw which the series 0 prsrns 10 End
~ as were There tail attached TO each prism,
.reb manner that when this screw is turned in one
way the prsms thrown into larger CIRCLE and when
ycie: ana thus we are abe, without moving the tee-
scspe the oolmatof at s0 to move any part of the
peYt taagram shows the instrument complete repre-
.ntaOn in relief OF the spectroscOpe employed by the
horizontal section was thrown upon the tcreenl. II
,oOks complicated, but not In the next diagram the
attached ready for use When this is turned 10 the sun
we get what call the solar spectrum portion of
0i COOIb-
KIRCHoFF's CHART OF SPECTRUM LINES.
IT, the photograph OF Kirchof7s map shown on the
screen throughout the whole length the spectrum is
marked with lines not bright bands, such as we have
seen before on the SCREEN but dark lines These dark
lines were first noticed by wOlaston, and afterward
Ftaunnofer investigated them very carefully and made
. man OF coo or ZOO them. But he never investigated
1ner cause 10 until KirchOf that their cause
was known KirohOf found-what was known before
fhaf the bright neOf sodium conceded with DARK line
sf the solar spectrum, and he afterward found'
what was not known before, except 10 q
very few that when bright light passed
through the vapOr of sodium, as Prof. TyndaL
beautifully illustrated the bright band OF the sodium
became a dark line This has been found 10 be OF wide
Application instance, tried the yapor OF silver
allowing those beautiful green hnes- could pass be
mind n q stronger hight than the electric night which
xoud be hard 10 find, but you can conceive OF tyOu
ond zee those bright turn into darkness upon
rbe screen These lines indicate iron I'd magnesium
IN the sun and certain other metals, such as nickel
Krchof found by experiment that very large number
of the other metals with which We are faminar are
aleo 10 he found IN the sun--nOt that ne
found the presence OF the metallic bright bands them
ssyes INT he formed the solar spectrum, and night
reside AZ he formed spectrum OF the metals. These
re the lines Of referring TO the diagramJ lie
found that every bright line of the iron there was
the solar spectrum. There are great many
spectrum OF the sun not que 10 the nOp
explained in any way but ne f0und that every
bright line metal represented by its analogue
the solar spectrum Here - taDe OF the met4e ~
present known to exist in the sun: