The evening telegraph. [volume] (Philadelphia [Pa.]) 1864-1918, 1868-11-19

hal0 OF 1alnJ nBnt calleu the cOrOna' Wnloh Is
generally supposed to be the SUMS atmosphere,
and is OF course invisible at ordinary times,
on account Of the dazzling brightness OF the
sun itself. In the portion Of this corona
which lies nearest to the SUMS surface, and
close round the body Of the moon, are seen at
various portions Of the circle jagged peaks aud
ridges-generally Of rosy light, red flames and
prominenees, as they are variously called
much brighter than the dim corona and much
less elevated, though some Of them have been
measured, and found to attain the height of
10000 miles. Like the corona, the promi-
nenoes are invisible except when the sun is
darkeDed, and every total eclipse in recent
times has been watched with the utmost keeu-
ness in the hope Of finding some clue 10 the
problem what these prominences were. They
might, ii was thought be solar clouds filed
with incandeseent particles less hot and less
brilliant than the photosphere, but still
bright enough to produce the beautiful phe
nomena seen during an eclipse; or, on the
other hand, they might be enormous masses
of flaming gas driven off from the sun in the
course of the violent action to which Gas the
sun-spots testifed) the superficial portion of
the suns mass was subject. In the same
paper in which Mr.. Lockyer announced his
solution Of the sun-spot difficulty, he sug-
gested the pertinent question whether the
spectrosco pc might not afford us evidence Of
the red flames which total eclipses had re-
vealed. The question was not mere barren
conjecture, for Mr.. Lockyer employed the
spectroscope, which he had mounted for
the examination OF sun-spot5, in dill
gently sweeping round the edge Of
the sun in search OF such spe-
cial spectrum as the prominences might
give. From the year 1866 these observations
were continued without result, and another
observer, MIR. Stone, who afterwards COM
menced similar search, was equally unsuc-
cessful; but at length, in the early part of the
present month"; spectrOscope of much greater
power was mounted, and Mr.. Lockyer was
soon rewarded by sight of the prominence
| spectrum, which, so far as the observations
! have yet gone, appears to consist of three
! bright lines-one corresponding exactly to the
| dark line c in the red portion of the solar
| spectrum, which is commonly considered to
| be due to hydrogen; another nearly coinciding
with the line + at the confines of the blue aud
green, which is also ascribed to hydrogen; and
| third at little distance from the conspicuous
sodium lines d, but clearly distinct from them,
and, curiously enough, without any CORES
ponding line which has yet been noted in the
! solar spectrum.
Before this result was achieved and COM
municated to the Royal Society, the eclipse
had taken place, and several observers had
! gone to India and other places within the
region of totality, armed with apparatus for
the examination Of the neutrality-suspicious.
| All of these observers had reported that they
| ROL u spectrum COLnpOSeu OF uueS hlOuo
the evidence of burning gas; but, either
from the necessary hurry attendant upon
observations during the few minutes allowed
| by the period of total observation, or from
| some other cause, the most remarkable dis
erepanees appeared in the positions assigned
to the lines. Captain Herschel who repre-
seRted the Royal Society, reported three lines
one absolutely identical with D. another not
quite agreeing with +, and the third some-
| where b c. Major Tenant who
went to Guntoor, in India, on behalf of the
Royal Astronomical Society, reported three
lines, G, d, and b--ths last being in region
where no other observer except III. Rayet saw
any line at all. M. Rayet, who was at Wha-
Tonne, considered that he detected as many as
nine lines-B, D, L, b, another unknown line,
two of the lines about +, and the line G.. 1t
will be observed that nearly ell the lines
named by these observers are given as actu-
ally corresponding with known solar lines. NJ.
Jansen, who represented the Academic des
Sciences and the Bureau des Longitudes, re-
ports the hydrogen lines as the principal lines.
AS yet the detailed accounts from these OBJ
servers have not been received; but it seems
probable, from the uncertainty with which the
position of some of the lines is spoken OF, and
the wide discrepancy between the results of
different observations, that the lines were de-
termined, for the most part, rather
by estimate than by measurement.
Although, therefore, the eclipse observa-
tions had removed all doubt as to the
gaseous nature of the prominences, and thus
anticipated the result obtained by Mr.. Lock-
yer, the discovery that the spectrum of the
prominences might be observed at any time
rendered 1t possible to ascertain the exact po-
sition of the lines with precision which was
far from being attained in the observations
made during the eclipse. Scarcely, however,
had it become known that the search for the
promiIenoes had at last proved successful,
when letter arrived in Paris from NJ. Jansen,
stating that, while making his eclipse observa-
tiops, it occurred to him that he ought to be
able to see the pTominence-spectr without
calling the moon in aid to relieve him from the
brightness of the sun. Accordingly, before
returning from Guntoor, he had made the
attempt, and succeeded in getting several
views OF the prominence-spectrum some
weeks before Mr.. Lockyer had achieved the
same result in England. 1t has often been
remarked how frequently scientific dis
eoveries are made by independent observers
at the same time, and perhaps the coincidence
was seldom closer than in this instance. The
French observer was the first who actually
caught sight of the coveted object but the
Englishman had been the first by q year or
two to suggest and commence the search, and
was the first to publish his discovery. His
results were announced to the Royal Society,
and by Mr.. De la Rue to the Academic des
Sciences, before the arrival of NJ. Janssen's
letter, which, singularly enough, was delivered
to the President OF the French Academy a
few minutes after more detailed announce
ment of the English discovery had been re-
ceived by him.
NJ. Janssen's letter, which appeared in the
Honiteur of the 18th instant, states that the