The evening times. [volume] (Washington, D.C.) 1895-1902, 1901-01-09
THE NEXT SOLAR ECLIPSE
Naval Observatory to Send an Ex-
petition TO SEmatra.

Extensive Preparations BEING Made
in May-TnuSuaIHy Interesting to
Astronomers Because the Duration
of Totally VIII Be Six Minutes.
Preparations are being made for the ex-
petition which will be sent by the Naval
Observatory 10 Sumatra for the purpose
of observing the eclipse of the sun on the
18th of May Eext. The party viii be IN
der the direction of Prof Skinner, and
will include Prof. Eichelberger. Assistant
Astronomer Littell, Prof Peters, Doctor
Jewell. and Mr.. Dinwiddie- These will
leave San Francisco on a Government
transport for Manila some time next
March.
The eclipse will be 4 total one and its
extreme duration of six minutes will rem
der il of especial value for the purpose of
observation II will be remembered that
the duration of the last total eclipse May
2S 1900, was but one minute and thirty
seconds its hrevity proving a great han
dicap to Observers.
L is designed 10 make the present eX-
petition very complete in all its appoint
ments. SO 0nh icing appropriated by Con
gress for expenses. The instruments nee
essary are being made in this city. These
include a set Of magnificent cameras of
gigantic dimensions by means of which
a series of photographs of the eclipse
viii be taken These photographs. it is
expected. win show the structural details
of the corona. or halo surrounding the
sun in a manner that it has never before
been possible 10 obtain. The data derived
from the observations made at the last
eclipse. re!ati : to the mysterious ap-
PendaEe of n aun. has proved extremely
unsatisfactory, and the real nature Of the
so-caIled gaseous envelope surrounding
the luminary remain. as great mystery
as ever
The structure OF the corona offers a
most magnificent field for scientific iuves-
tiga ton observed one Of the authorities
al the Observatory, as upon an intimate
knowledge Of its real nature may depend
the solution of the secret of the suns
energy and the law governing its interior
phenomena as observed through the tele-
scope II Is only during a total eclipse
that the corona may be seen and studied,
and the tine allowed for this purpose by
the forthcoming event is unusually am
pie.
1T Is now known tnat tie extent. form.
and general appearance OF the corona are
apparently determined by the same cause.
whatever that may be. which is active
in producing sun spots. IN years when
sun spots are most abundant, the corona
seems to be the most Guiescent; It is
then distributed nearly uniformly around
the sun, and us structural details are less
observable than at other times When
the sun spot activit". IS at a minimum, as
viii probably be the case next May, the
corona appears 70 be violently disturbed;
il throws out long streamers in, or nearly
in, the plane Of the suns equator, while
about the poles a brush-like appearance
of numerous curving jets and spray be
comes an equally marked feature More
over, the corona appears to shine partly
by reflected sunlight, as do the tails of
comets, and the opinion is now growing
among astronomers that the phenomenon
is, TO great extent at least, electrical
That sun spots may be attributed 20 the
same force has been shown by recent OBJ
seFyations made at the various magnetic
oJservatories throughout the world which
have established the fact that the ap-
pedrance Of the sun spots is always con
tempoTaleOUs with electric storms upon
the earth Of greater or less violence IN
proportion 70 the size Of the spots
Besides the corona. the so-caIIed red
prominences are, perhaps, the most i'm
pOrtant features OF the photographs Of an
eclipse They are plainly 20 be noted on
the pictures IS small prominenees CT
light behind the blaze edge Of the moons
disc In reality they are huge jets Of
blCCd-red VapOr- extending 10 height, in
some instances of 50, 900 miles or more.
They are fan-shaped at their highest por-
tons thus resembling ornamental TOunt-
aims SpectrOsccpic analysis has been
successfully applied 10 this phenomena
and the spectrum is found to consist Of
bright lines indicating that the promi-
nences are masses OF glowing yapor- All
observers are agreed that among the
bright lines these Of hydrogen are per
ceptihIe while one yellow line has been
mistakenly ascTi6ed to sodium.
1t had been observed. even before the
prGEuiuences were noticed, that there eX-
lists = border Of ed color around the
solar us which can be recognized on
the eastern side just after LOJaIity has
commenced. and on the western side JUS
before totality ceases. Late observations
abundantly confirm the discovery. and Il
has come 10 he definitely admitted by all,
that a continuous red envelope surrounds
ire sun TO depth of 1000 to 1 0CG miles.
This envelope is termed the chrome
sphere. or chrUmatOsphere. and the prom
inences are regarded as extensions of this
red garment of the sun Past eclipses
have proved conciusiveIy that the hydro
gen flames belong 10 the san, and not 10
the moon. as was contended- i method
mas been lately discovered Of observing,
with the spectroscope those bright hydro
gen prominenCCs every day The spectre
scope has also revealed the presence in
the sun of the so-called c5ronal gas Up
TO the present time this gas has not been
discovered upon the earth