New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1869-07-30

be closely observed with spy-gass uarh l'o' may
be seen crossing it; but he dld not follow up inc
subject In 1914 German optlclan hameu frlu"no
fer gave attention to these spectral lines and went
90 Co. &c a. mako n map of them. The next inyesti-
o+or ,bo tool, ND the subject was DIR. John w. ORA
ner If tbis ctv More than twenty-five years ago he
introduced into this country the spectroscope OF
Fraupbofer and so modified its construction as to
| iurroes the fixed lines upon sensitive chemical
surface and get Photographic map OF their dlstri-
bution lie showed four great groups oil these lines
bevond tbe limit Of the violet ray, aud doubled inc
number of them up to that time known. About the
Same time DIR. Draper published several papers on
spectrun ANALYSIS, anticipating various things which
| have been lately brought forward az new
But it was in 1859, just ten years ago, that t"o
| German chemists, Bunsen and Klrchoh, worklhg
| together took the next important step tha1 HIS
become so fruitful of recent results. They diseoy-
cred that each chemical element when burning IN
aame omits light which, when passed through
prism and forming spectrum, has lines or marks
peculiar to itself These lines might be TAKEN there
fore as new properties of the elements, and could be
used Ia distinguish and detect them. 1t is only IN
| the condition of rdpor that the elements produce
| their peculiar lines. If platinum wire, q SOLO, DC
heated TO whiteness and its light passed through
PRISM it gives q continuous spectrum; but IL pla-
tinum DO vaporzed by the electric current, Its spec
trum becomes broken, and there is series OF bright
lines separated by varying intervals Of darkness III
zinc be vaporized it gives beautiful bands OF red ana
| blue, while vapor of sodium gives two fine yeiioW
| lines situated close to each Othor new ana most
delicate mode of chemical analysis was thus found,
and the very first result obtained by was the DIS
coyery of several hitherto unknown chemical ele-
meuts Prof Bunsen, in examining the ash lett aiter
the evaporation of some mineral water, discovered
| NJ n belong 70 known
element lie then boiled down Al tuns OF this water
and from the mineral residue he extracted two new
metals resembling potash one Of which no named
| Pubidiam, because it gave dark red line ana tho
other CGsiun, from its producing buish-gray line
The lines produced by the burning vapOrs OF the
clements are variously cOlOred, but always bright
with dark interspaces; but in the spectrum OF the
sun and stars this is exactly reversed the lines being
| dark and the spaces bright. KrchOH explained tins
beautifully on the principle Of absorption which we
will try TO illustrate. five go into glass store with
n violin and produce tone by drawing the bow
across one of the strings certain of the glass vessels
will be set singing they will catch mp and give out
| the same musical note which proceeds from the vio-
lin But only those vessels will do this which are
capable of vibrating in unison with the string OF OF
irving out the same note that they receive. In this
case the sound of the string is said to be absorbed by
tho vessels which are capable of emitting only ybra-
| tions of the same rate Surprising now we have
candle-hame containing sodium vapor, which gives
| the bright yellow lines in its spectrum. III then we
take an electric light which is of course very much
| brighter, and containing also sodium Yapor, ana
LET il shine through the candle flame, the bright yell
low lines do not change their position, but they In
stantly turn dark The explanation is that the can
do flame absorbed the same rays that 1t gave out
| that is, it stopped the bright sodium rays OF the
electric light and letting all the others pass, the
contrast becomes so great in the spectrum that the
lines Of absorption appear dark lines Now in the
sun IL is supposed that there two sources Of light
an external photosphcre and an inner nucleus of in
tenser brightness so that the intcnser light from the
inner source undergoes absorption as it passes
through the outer sphere aud hence the solar lines
appear dark. A beautiful yerifcatOn of this princ
pie is furnished by discovery Of Lockyer and JAMS
sen that from the very outer edge Of tho sun, and
consequently where we do not get the rays from the
nucleus, tho solar spectrum gives bright lines this
outer sphere is therefore termed the chromosphere.
The constitution of the sun is now held to be
proved by spectrum anayss-that Is We know to a
moral certainty that certain elements existing on
the earth exist also here The spectrum OF iron va
por for example. gives sixty seventy bright
lines. II now we place this beside tho solar spec
tum the brightlncs are found exactly to correspond
TO a system Of dark lines in number. breadth, posi-
ton, and interspaccs-a coincidence that. Sixteen
Of the elements we know upon earth are thus found
to exist in the The spcctra Of tho stars have
been studied with great assiduity and success by
Father Sech OF Rome, Mr.. higgins OF London, and
Mr.. Rutherford Of this city About eighty lines in
tho spectrum Of the star Aldcbaran have been
mapped, and It has been shown TO contain sodium
magnesium, hydrogen, bsmuth. tellurium. anti
mony, and mercury, while Sirius gives indications Of
| la n snlium irou and nv
drogen.
But the uscs Of spectrum analysis not confined
TO original chemical research it has practical app
| cations which should not pass unnoticed. In the
BcsScer process Of converting casron into steel it
is Of great value. Castron differs from steel in con-
tanning more carbon and is made into steel by burn
ing out the carbon by means Of blast Of atmospheric
air sent through tho whitc-hot molten mass. Five
tuns Of cast-iron by this process, converted in
twenty minutes into caststeel. The success Of the
operation depends upon the blast being stopped at
the right moment for if discontinued too soon tho
mass becomes too viscid to be poured ont or if con
tnued too long it crumbcs under the hammer. By
and Of the spectroscope the appearance and disap-
pearance of the lines in the flame afford exact in
dex to the progress Of the combustion. This nstru-
ment also proving valuable ally TO justice in its
evidence in criminal cases 1t detects with unerring
certainty even the onethousandth part Of grain of
tho red coloring matter of blood-stain.
1t is difficult to convey clear ideas of tho subject
treated by Prof Roscoe without the aid of diagrams
no has accordingly illustrated his work profusey
and beautifully 1t is in the form Of lectures clear
and popular IN statement and in the absence of n
course Of experimental demonstrations il is the next
best thing. The publishers have performed their
part with skill and produced work which it is not
too much to say is worthy of its theme.
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