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

about ten minutes before the extinction Vi 'ho SUI 49,,
Gloom increased very perceptby. The distant h'ilS
Looked duh and misty aud the sea assumed DUSK ny
neoraDce like that presents during rain The dayS'
that remained had ycOwish tngc, and the azure 'uo
of the sky docpeued to a purplishNiolet nue. P"it
larry toward the north Bat RotwithStanolnE 'n'a0
Gradual changes, tie Observer could haIuiy 10 IC
oa,ed for the wonderful spectacle that preSenIcu
it.elf when he withdrew his eye Ho" tno
telescope, after the totay had come on 10 Eu1o
,roupd him for a few seconds. The southern heavens
were on of uniform purple gray Color tho Only ihuF
cation OF the SUMS position being the luminous ooon,
the light Of which contrasod strhlnSV Win tna u 'nO
srronndo0 y In the zonith and north OF 1t the heaV
ems were OF purplish violet, and appeared very pea
while in e northwest and northeast broad bands OF yer
light intensely bright produced an euec'
winch no person who witnessed 1t can ever forget Ao
crimson appeared to over largo portions Vi '0 s
in these directions irrespective OF the eIouls'
higher attitudes the predominant color was Pu'po' "
nature seemed TO be overshadowed by an uu, -"
oroom. the distant hills hardly visible; INC sea
lnrid rca and persons standing near the observer
had n male llyd look calculated to produce tho noS'
if,I sensafioDs The darkness il it can be so leneu'
had 10 resemblance TO that OF Night Az N'ioU' i
within the shadow. the planets Venus Pioiou,'' "u
Mars and the brighter stars OF the FIRST "
Mainly seen during the total eclipse. Animals were ire
oueutly much affected. Cocks crowed al heiSinsDoR
borgb tho sun was only hidden there 80 seconds ana the
birds sought their restngpaces as II night hau como OH
II ould not be surprising If many Of the phenomena
which are usually peculiar TO the tota phSe shouu DO
oonerav observed even in the partial phase OF the
ccI,nso next month For though partial, the eclipse IS
very large throughout the United States and the enects
OF the SUMS observation will be very much aided by tho
Iatcpess in the day at which the greatest observation VIII
take placeabout o'clock in the afternoon at ana near
this CITY, Possibly something Of the corona may be seeh
especially if we take pains to off the remaining
bright crescent Of the SUM-
THE INSTRUMENTS REQUIRED FOR OBSERVATION.
Where nothing better can be had, bit Of plain glass;
smoked over a candle lamp in some parts moro deeply
shaded than in Others to suit the varying intensity OF Tue
SIMS ravs during the progress Of the eclipse VIII choe
the observer to most Of the phenomena In lhe cy
1t will be easy procure pieces OF the red or ruDyhVou
glass Of different shades depths, from most OF the
GLACIERS which may be used with advantage instead OF
the smoked glass Those who can command good
operagass or small telescope OF any kind provided with
shade glass to screen the eye will Of course have bet
ter view But the regular astronomical telescopes prop
erly mounted and largo as can conveniently ne trans
ported TO the place Of observation VIII ahord the
best means Of detecting all the nice points OF the po
nomena The Government parties, sent out to dherent
stations along the line Of the total eclipse,
will also be provided with the means Of taking In such
largo telescopes Photographic impressions OF the phe'
noena at their various stages These photographs can
be studied at leisure and in connection with the impress
sons left memory OF tho Observers VIII serve 10
ton of the SUM- Besides these usual means OF observa
ton comparatively now instruments for detecting polar
lied light and for determining the chemical constitution
of the sum- and Of the and red protuDerahceS
will DO employed. The spectroscopo is the I'M
portant instrument for making this curious chemical
analysis Of distant object Will 1t be possible 10 con-
vey to the general reader clear idea OF the principle OF
this instrument so that no can realize its arreachng
pOweri Let us try.
Sir Isaac Newton placed triangular prism OF glass In
the pa OF solar beam, and obtained the elongated
spectrum Of the sun, consisting Of the rainbow colors
from the red 10 the violet. Dr. WOastOn subsequently
discovered number Of Cark lines crossing this spectrum
at light angles to the direction in which the different
colors were dispersed Fraunhoer, eminent German
opcian looked at these dark lines In the spectrum
through small telescope properly mounted for the pur-
pose He found their number vastly increased but her
in the several parts Of the prismac spec
rum perfectly uniform and constant for each particular
line lie designated the particular lines and their POSI-
lions in the solar spectrum by the letters Of the alphabet
A. B. c. D. sc. Thus, the position OF the line d. Tor ex
ample definitely known to scientific men as the line
at the end Of three inches foot rule These dark
lines in the solar spectrum called the Fraunhofer
lines The Of these dark lines has been discovered
and thence has arisen the construction Of that wonderful
instrument the spectrOscOpe
It consists Of an arrangement for passing fiat beam Of
light through Of several prsms in succession and
then viewing the resulting spectrum through a small
telescope attached to the apparatus divided scale IS
seen at the time by which the position and dis
tances Of the FraunhOfer lines measured. Now II
light match before the prism and observe It's spec
trum, we shall find it continuous that is from red TO
violet there is gap there dark lines. But we
burn something which does not give perfectly white
light something containing some OF the metals, wo shall
very bright coored lines exactly in tho POSI-
ton on the scale occupied by OF the dark lines Of
the solar spectrum. This observation is the germ OF
Kirchofs discovery which has led TO the application OF
the specrocOpe to the most refined chemical analysis
It's found that the yapOrs Of metals and gases generally
absorb those rays Of the spectrum which the same Vapors
! and gases themselves emit.
BY numerous, precise, and oftrePeatcd experiments
| the following laws have been established:
| l. When solid or liquid bodies are incandescent, they
| give out continuous specra
H. When a solid liquid body reduced to state Of
gas or any gas ITSELF burns the spectrum consists OF
bright coored lines only and these bright lines are differ
ent both IN color and position for different substances.
Ill When light from solid or liquid passes through
gas the gas absOrbs neutrazes those particular
of light Of which its own spectrum consists
We arc prepared to understand by OF these
laws what the OF those dark lines in the solar
spectrum The intensely heated solid or liquid body Of
the sun would send a continuous spectrum, with no
dark lines in 1t; but these rays Of the spectrum
have TO pass through the flaming gas OF his pho
tosphero, which contains the yapOrs OF various
metals other elements suspended in It, These vapors
enforce their usual tribute from the rays OF the connu
Gus spectrum which, therefore, arrives in the instrument
despoed Of certain lines OF light in the different colors
On the other hand il could receive the spectrum from
the gas itself land the spectroscope is arranged
do this also) we should have those dark lines lit up
with brilliant lines corresponding both in color and posi-
ton the elements from which they 1t is in this
way that the rosecolored projections have been ascer
tanned TO send precisely the bright lines Of hydrogen
In the regular spaces belonging the spectrum Of this
element.
Among the instruments to be used and observed are
the barometer thermometer and hygrOmetcr to deter