The evening telegraph. [volume] (Philadelphia [Pa.]) 1864-1918, 1868-07-27


differently from ray OF direct light
when noth are passed through a doubly refracs-
ing prism. The direct beam is split into two
sec ions, which, in all positions of the prism,
are OF equal intensity; while the reflected beam,
similarly divided, shows two spots OF light
which, in certain positions of the prism, differ
eon,deraDy II Gr9hness: a. AN &naiSSs nods Oh
this principle and it was then determined that
it shOne by reflected hight, and was therefore
not seli-luminous. From the'e ooseIvt,lons, S,,,
ROYAL has arrived At the op Mon that there
must be an atteDuatei atmosphere encom-
passing. the earth to ., such soon an extent eat
that il is the lighting up OF the regions of this
atmos phere in the immediate vicinity Of the
moon that gives rise TO the corona and its vary
The late Mr.. Baily excited curiosity for time
by bis announcement that just before the COM
mencement and just after the end Of tosality OF
a solar eclipse, or in other words when the limbs
of the sun and moon are just touching inter-
nRlly, the narrow line Of solar light breaks up
into luminous points, aud presents the appear
ance of n string of bright beads. This pheno.
meUon, which has since been recognized as
"Baiys beads" IA sometimes. but not al ways,
seen; 1t is very easily account ed for The moons
edge is not perfectly smooth; mountains and
valleys give 10 q 5eTrated outline, and when the
margins OF the moon and sun are just overlap
ping, the suns margin Ia just visible through
the chlnks and crannies of that of the moon,
and gives the appearance of chaplet OF beads.
sheet of paper laid under a saw, so that its
edge just peeps between the teeth, repeats the
appearance which, as it leads to nothing, may
be dismissed forth with,
But by far the most interesting and suggestive
of eclipse phenomena are the red-Colored masses
of light that are seen to exude apparently from
the moons circum iereu Ce. These protuberances
were first Culsorily noticed oy one Captain
Stanyan, during the eclipse OF l706s Flamsteed,
England's first Astronomer Royal, says in a
letter 10 the Royal Society that "tbe CAPTAIN is
the first man | ever heard OF that took notice of
red streak OF light preceding the emersion OF
the SUMS body from total eclipse, and 1
| take notice of IT to you because 1t inters
! that the moon has an atmosphere" Then
at the eclipse of 1878 two other observers saw
| something of the same character. But, curl
ously, these records for a long time escaped the
attention Of Astronomers and when they turned
their eyes and glasses upon the eclipse of 1S42,
they were ignorant of what their predecessors
had seen and noted. They gazed al the slowly
disappearing sun in anxious expectancy, pre-
pared to see something strange, but knowing
not what. Imagine their surprise when, as the
last glimpse of the solar disc was
shut OPT by the advancing moon, they
saw the black edge OF the latter gar
nished in some parts with a blood-red bOr-
der, aud in others with sheaves OF roseate light
and mountains of glowing fame. The observers
were electrified with this apparltiOn; they were
unprepared to measure or to depict; aud before
they had time to collect themselves, and satisfy
their eyes and minds that neither had been
under illusion, the sun reappeared, and the
marvellous phenomena vanished. All anxiety
then came TO be centred upon the next great
eclipse. This happened in 1851. The expert
enCes purchased upon previous occasions were
turned TO account IN preparing instructions
and laying down schemes of observation
for this. The British Association, with the
cooperation of some foreign astronomers Drew
up and circulated pamphlet OF suggestions to
intending observers aud instruments and eyes
were made ready for acrion. All the phenomena
OF an eclipse were provided for as regards ooser-
vat,on and record OF them: bat the 'red promi.
nences' were literally the promlnenl points OF
interest. The shadow oath OF this eclipse passed
over northern Europe and aloug 1t, chiefly in
Sweden, the observers Ike party OF skir-
mishers, disposed themselves. This time they
were forewarued, aud so forearmed; knowing
what to look for and how to see it.
Circumstances proved favorable, and when
the to'ality came on, the anxiousiy eX.
peoted IUsy eXcresCeuces shone tortu In all their
glory. Many observers saw them, estimated
their size, and mapped and drew them. Several
of the questions that had been raised we're
decided Foremost among these was, whether
the pfominences were attached to the moon or
to the sun? Well, some observers asserted that
protuberances On the eastern side became
quickly hidden, while Others spraug up on the
western side: that is, they were respectively
covered aud revealed on the eastern aud western
borders OF the sun by the advancing moon. So
it wa established almost to "A certainty that the
prominences were part and parcel OF the sun.
But other bewildering questions arose.
When the drawings of didercnt obser
vers were compared, discrepancies were
revealed that were scarcely attributable
to errors of observation. Uoon the
forms ana CharacterStlCS OF some OF tne more
remarkable OF the red masses no two observers
were in agreement. Pictures and descriptions
were alike irreconcilable; they left an i'm ores
sion, upon the minds of those who eXa mined
them, that there was some mrage-lIke effect
that manifested itself variously to different
eyes.
Nine years passed away and at their en1
came the famous eclipse OF 1860, which was most
favorably visible in accessible parts OF Spain
| During the nine years q valuable adjunct to
| telescope observation had been pressed into
/ the astronomers service. Photography, in its
/ youth in 1851, had been wrought to pertec-
/ tou by 1860, and has been successfully
applied to the depletion OF celestial objects,
notably the spots on the sun aud the surface
| irregularities OF the moon. The suggestion had
| been made in 1851 of the great advantage that
the eclipse of that year, but little action was
taken, as the art was then so young. But
| when preparations were in progress for the
| Spanish eclipse il occurred TO Mr.. De la Rue,
| the father of celestial photography, TO lit out a
| suitable apparatus for making the eclipse
| phenomena record themselves. and thus avoid
the vagaries and impertections OF eye and
| hand dehnea'ion. This was done. "photo-
Telegraph" and the pertaining apparatus and
chemicals formed prominent feature in the
| expedition which ii. NJ. S. Hlmalaya bore from
! Plymouth TO the northern ports OF SPAN In
July, 1860, This expedition comprised goody y
band of European astronomers and observers
for I'LL who were prepared 10 do aly good were
made welcome on board the transport, which
had been literally placed by the government at
the disposal OF the Astronomer Royal Every
thing turned oHt iaVorably tor the observers,
and Mr.. De la Rue was fortunate enough to
secure two negatives during he tOtallty, on eacl
OF which the led protuterances were vigorously
Impressed. Two more valuable pho o'ographs,