New-York tribune., 1873-01-25
CELESTIAL SPECTROSCOPY.
LECTURE Ry PROF c. A. YOUNG.

LECTURE BY PROF. c. A. YOUNG.
zuE ASTRONOMICAL CoNQUEsrs OF THE sPEcrRo-
sCOPE-THE COMPOSITION AND MOTIONS oF
TIE HEAVENLY BODIES APPROXIMATELY DE-
TERMINED.
Prof. C. A. Young of Dartmouth College de-
Hyered the third Of the Of scientific lectures be-
fore the American Institute at the Cooper Union. last
evening His subject The Astronomical Conquests
Of tue spectroscope lie introduced TO the audi
snce by Proi. Barnard OF Columbia College The asdi
snee was large and contained many ladies' The lee
turer spoke with great rapidty largely illustrating he
statements by diagrams projected the screen p'
pasg,c lantern Only part OF the lecture h givcs below"
evsng 70 the pressure ON our columns
THE LECTURE.
Isis with some reluctance and with ies"s i''','
sNn 20 trepdation. thai appear for the nis' u.r =.
fofa a metropolitan audience, in n room ~ -
sonant with the voice OF cur ohiei aloss' ,,, 90
science But l console myself with the ~, -
shIs proximity some respects S ,no.s q,
eesting COMPARISONS, vet, on the o'l'ei ,,'"' -,
vho had the Measure Of hearing Prof. 1yhuai' mus
r.. ,arnoa so 10 love science for Its own sake '""
Won xVn h. clad and ready u listen 10 "h"'e''
"a ott,r of interest Importance Inc supeo'' -.
90 ono Of Cgeat interest, ana am W "s
,et IT before you in as PLAN anu si"pl0 s
- as can. consistently with distinctness ana "'-
- "s sbsu have 20 call your attention 10 the images
n me screeu hut shall aim 10 be az simple aS PoSoo
a, citing hetore Won what has been accomplished III
de field Of Astronomy by this great sun OF ihouern
.epeefhe instrument which has done more 10 eA'enu
a.. ,e of astronomical observation than any other
,, Invented II is hardly necessary TO show you the
.strm vet shall be glad if yen again see with your
, ewes the indications which different substances give
a, tner presenee in the light issuing from the prism
IMAGES THE SCREEN
on TIC screen will appear succession OF images py
Of narrow Slit through which the light is allowed
70 PASS prism is placed that the light is ophged
O. rss through IT, You have then beautiful succession
uf ooors-rod yellow, green, and oue. suosutuVe a d
material which gives one several lights, and you Will
~. these results for yourself have the spectrum
Of .od,nm and you will find once in place of simple
ooutluuous spectrum, one OF several bright Dands'
each a perfect image OF the slit If IT is narrow
they arc narrow II it widens, they wlden' eaeh
true picture of the slit formed by some one KIND OF
hight The white composed OF as many different hgnts
ss there are lines in the solar spectrum.
OF course, / could through the chapter WIN
metals each giving its own spectrum, some OF theln ot
greater brilianCy and others OF less OUT Win Sre
shaercnce between them. Whenever we are able To
metal into the state OF Vapor u ewes us ls slgn
y which II may distinguished far as It's gnt can
he seen: and can judge, there If no ll 10
that for light appears to come from almost lnnnlte uls
faures You will notice that now the red line Is almost
cone and the purple lines almost gone; ana the
zine having been nearly consumed the copper nasnes
clearly than at first But TINS arrangenent o
fhe apparatus. although good indeed fOr shOMns
INC lines 10 an audience, would not answer at an il
Astronomy. OF course we cannot bring the stAI h'V
the place Of the lantern TO throw ts gh On the sui AM
could II would be too FAINT 70 Oe seen, We mus
therefore employ different apparatus, which ls Know
ss the epectrOscOpe. IL consists OF prism ana twe
tubes, one known as the eOihmatoI WhIcn Lac ZEN
near end and throws the light Of the star upon ht
st and the other acts precisely ike telescope 10 view
the image OF the SHIT which is narrowed down py
The light passes from the slit through the prism
then through the telescope, and is seen by the eye
TIE MsTRUHENI BY WHICH STARS ARE Examined.