New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1878-08-17
THE SOLAR ECLIPSE
WORK AT THE RAWLINS STATION.
~. HENRY DRAPER TELLS WHAT WAS ACCOM-

WORK AT THE RAWLINS STATION.
M. HENRY DRAPER TELLS WHAT WAS ACCOM-
PLIsHED BY HIMSELF AND HIS ASSOCIATES.
IRON AdUaHce SHEETS q ne american Journal Of 9e,enee
AS | have recently been giving attention TO
fhe subject OF solar specscOpy In consequence oil my
discovery OF oxygen in the SUD- u seemed 70 DC desirable
gain as precse an idea possible OF the nature OF the
Corona because the study OF that envelope has been re-
erded "a Impossible at other tunes. The main point TO
ascertain was whether the corona was an ncandescent
gas shining by its own light OF whether IL shohe ny re-
For this purpose organized an expedition. and was
fortunate enough TO secure the cooperation OF my friends
ProtessoTs Barker aud Morton and Mr.. Edison. The
scheme OF operations as follows; lst the phOtO-
graphic aud WIZ 40 TT re GA
myself; ID, the anayZing st spectfOseOe Ws chdTge
o. Professor bsfne " gt mes or else Of DARK Fraan
hOier lines In the corona 30, the poascoPe examine
tOus were eOndded to Professor Morton, VINO was asc
10 spend few moments in looking for bright OF dark
lines with hand speetrOscOpe; 4th Mr. Edison carried
batieTies resisanee coils Thonsons galYanometer oTe
required to determine whether the heat Of the corona
TINS entre programme was successfully carried out
and good fortune attended as IN every particular.
The results obtained were First the spectrum OF the
corona photographed and shown TO be OF the same
character that Of the sun and not due % speca IN
eandeseent gas; second fac photograph OF the corona
obtained, extending In some parts 10 heignL OF
more Than twenty minutes OF are-tnat -, WOse In
100000 mles third, the kraunnOier DARK INES were
observed by both Professors Bankers ana morton
the corona fourth, inc gOs sle5 ss womd
to reflected solar light fifth, MT EDISON iOuhu
dex beam hight entirely of the scale OF the gayano-
meter Some negative results were also Ieaeneu, Ino
principal one being the AJAX or so-caed corona
hue was etber very else not present at all III inc
upper part of the because II could not be observed
with sitess spectrOseOpe, and tae SIT specuOscOpe
The general conclusion that follows from these results
Is that on this occasion have ascertained the true
nature OF the corona VIZ 1t shines by light reflected
nom the sun by cloud OF meteOfs sutIVuhuns '9sV
pmnaIy, aud that former occasions IL mas peeu ln
n.tfdted With materials thrown ny IIOAn Jug
sphere notably with the l474 matter snu nSSTogSn,
has taken place 70 scarcely pereeptible degree
Gently. Tins explanation OF the nature Of the corona
ecOneies itself 30 well with many facts that have beeh
mmcGlt 10 explain such as the low pressure ~ ne SUE
lace OF the sun that It gains thereby
aehromao objective Of SIX Inches aperture ah9 t@ehy
one inches focal length loaned ny Messi.. y, q a. % an
thony oil Rew-YOk; this lens wac Attached RUN
efiurd dhractiOn grating nearly Two luehes hquaie
ruled on spectrum metal We had aso Iuli ssg ol
winch In my experience is fully three times QUICKER
than any other process: The arrangemeht' Win tIs
plate holders, ETC., will be designated as photo
ieiespecroscope Ths requires farther DESCRIPTION
ior success in the Work 1t was INTENDED 20
Of the corona, was difficult and In the opinion OF
many Of my friends impossible. In order 70 nave
every chance OF success II II necessary 70 procure
lens OF large aperture and the shortest atalnabe FOCAL
length and 70 have grating Oi tue largest SIG au
insted Ia such way to utilize the beam OF hRht 70
me best advantage, Moreover tue apparatus must ~
mounted eqatOnay and driven oy eockwoIk 80 t nd
we Photographic work must DC done ~ the mOst sS-
eitive process After some experiments during the
summer OF 1877 and the Spring Oh 1876 tho following
form adopted:
The lens being OF inches aperture ands 81 inches
local length gave an image OF the sun less tha a OF
~ men IA diameter ana OF extreme brlancY before
me beam OF light tue ens reached FOCUS IL was
Intercepted by the Rutherford grating set at an angle OF
sixty degrees This threw the beam on one sue ana
produced there three mages-a central one OF the sun
end either side Of II spectfumj these were received
pa three separate sensitive plates; one OF THESE
lpeetra was dispersed twice as much as the Otier,
vat L. gave photograph twice as long IAls last
photograph actually about Two inches long ~ tne
scnie region H. now, the light Of the corona was from
Heandescent gas giving bright lines which lay ia the
octEie region OF the spectrum should have procured
ung-shapod images one ring for each bright me- On
ne other hand the light Of the corona arose from M
eondesoent solid liquid bodies rejected hgt
ron the san certain 70 obtain long band IN my
Photograph answering 70 the actnic region OF the spec
trgm II the light " as partly from gas and partly from
neeted sunlight. result partly Of rDgs aud partly
baud would have appeared. fr
tfeasdla,ely after the totauty was over aud on