The San Francisco call., 1896-08-02

Before the present week has passed as
tronomers will have cleaned some further
knowledge about the mysterious surround
ings of the sun, which for centuries have
been cause of wonder and investigation
when revealed to view for few minutes
by total solar eclipse.
The intensity of sunlight is such that it
is only on the rare occasions when the
moon acts as a screen, by passing between
the earth and sun, that the solar append
ages, the chromosphere, the prominences
and the corona can be most advantage
ously STUDIED. The latter, indeed, has
rarely if ever been discerned at other
times This is the incentive that has led
astronomers from all parts of the globe to
travel to those favored spots that lie in
the track of the moons shadow, with in
struments devised years in advance and
plans prearranged so as to forestall any
obstacles that might interfere with their
aims.
California has not forgotten the view of
the suns corona obtained January 1, 1889,
and her astronomers are foremost in the
expeditions that have been prepared to
observe the eclipse occurring on the 9Th
of this month in far distant lands, for the
sun has set on the Pacific Coast before it
commences.
They are fully equipped with the best
portable Instruments, and all expenses
including that of journey to Japan, have
been betrayed by the generosity OF Colonel
G. F. Crocker, Mrs. Phoebe Hearst and the
Hon. William NJ. Pierson.
As may be seen from the diagram rep
he rs &afo onla
tapering shadow projects from the moon
to the earth, and though correct relative
sizes and distances are necessarily ignored
it may be seen that the dark shadow
meets the surface before the cone is ter
minated, which occurs when the earth 8
satellite is at or near perigee and also at
or very near its node. 1t will then be
some thousands OF miles less than its
mean distance of 238, 800 miles from the
earth, and its disk, being nearer than
usual, will seem slightly larger than that
of the sun, and will cover that luminary
completely for few minutes.
The lighter shading in the diagram is
the penum bra, which extends around the
darker shadows or umbra, and falls on a
much larger area, in which the sun is seen
more or less partially eclipsed; but these
views nave not the scientific Importance of
the few minutes of total eclipse with
which limited area is favored.
These valuable minutes will be well
utilized by the dozen or more parties who
have travelled afar to waylay the small
shadow as it fits over the path marked on
the accom- panying map. commencing in the
Arctic seas near Norway and terminating
in the North Pacific Ocean. This path of
totality on the present occasion, as may be
seen, lies far from the centers of civiliza-
ton and the radiance of the corona will
glimmer unseen over the wilds of Siberia
and be mirrored only in the needless waves
| for many thousands of miles.
1t is to be hoped, however, that many Of
its choicest rays may fall on the object
| glasses that have been sent 80 far to re-
| feet its marvellous structure. While the
| features of the solar disk may be observed
at all times with magnifying power, all
| the strange surroundings beyond it are
| invisible to observers in general. Close to
| the limb or circumference of the sun lies
| the chromosphere "like a prairie on fire, :"
though luminous heat there, even when
red and fire like, is far beyond the mere
| burning stage, all parts being fused and
vaporous to an intense degree unknown
on this earth. At intervals much higher
appendages appear of the same glowing
hue, which is due to hydrogen, the chief
constituent of these two phenomena.
These high prominences, often treelike or
cloudlike in form, varying in height from
thousands to hundreds of thousands OF
miles, are probably jets of the lighter solar
substances thrown out by the violent
activity within the intensely heated sun.
The chromosphere and prominences can
be s en- fairly we'll at almost any time by
means OF spectroscope, though the alb
sence Of sunlight considerably facilitates
observation of details, but the corona
which extends far beyond them is the
main object of attention during totality.
1t is then clearly visible to the naked eve
and has been observed since the earliest
| ages with wonder and admiration, As the
body of the moon, in passing between the
earth and sun, first encroaches on the
west side, the orb of day assumes strange
gibbous shape and gradually iminishes in