New-York tribune., 1901-05-18
THE COMING SOLAR ECLIPSE.

Perceptible headway is made in mans
knowledge of the constitution of the sun and
the forces at work in it every time that n total
eclipse of that body is satisfactorily observed;
but there Is still so much to be learned that
the interference of cloudness in solar eclipses
is always the subject of keen regret. More
than the usual anxiety is justified in the case
of to-days eclipse. The period of totality is of
exceptional duration, and the opportunity for
investigation unparalleled for many years.
Moreover, the weather records for May during
the last few years do not encourage lively
hopes of clear skies at those points in the East
Indies where the phenomenon can be most ad-
vantageously observed.
Several facts have been fairly we'll eStab-
lished by the last three total eclipses of the
sum- There is no longer much use in hunting
for an intra- Mercuplal planet. The precise
position of the most characteristic line in the
spectrum of the corona, about which there has
been some uncertainty, has been determined
by Campbell. although no one can yet tell what
chemical element il represents. 1t is now toler-
ably certain that the corona assumes a differ
ent form at the minimum stage of the eleven
year sunSpOt period than 1t presents at the
maximum. To-day practically no one, unless it
be Sir Norman LOckyer, questions Professor
YOung'S belief that the layer of metallic vapOrS
which turns the lines of the solar spectrum
black is distinct thing from the other solar
envelopes, and lies down close TO the light
giving cloud shell of the sun. The sudden
Frightening of these lines for single instant,
both at the beginning and end of totality, has
been seen and photographed by too many per
sons 10 leave any doubt TO the genuncness
of the reversing layer" or its position An
other gratifying advance in eclipse work dur
ing the last few years Is Professor Todds
demonstration OF the value of automatic
mechanism to control cameras. instead of rely
ing on fallible human attention and skill at a
critical moment.
Among the questions with which experts in
solar physics are still wrestling are these:
Does that vast. silvery envelope of the sun.
the corona, rotate Mt exactly the same rate as
the orb which it surrounds? OF what mate
rials is the corona composed? Do the well
defined streamers which extend from the solar
surface to the outer regions OF that appendaGe
originate in places where spots and prominences
give signs of eruptve action. are they en-
tirely Independent thereof? What tempera-
lures prevail at various elevations in the CO.
roma? And is its light direct emission, or Is
It sunlight reflected from small. cool particles
in that attenuated cloud? Concerning these
and other problems the evidence is yet made
quate or conflicting, both
Again, though It needs verifcation before 1t
can be fully accepted, there is growing
suspicion that the sun generates electricity as
we'll as heat and light. The repellent influence
of that body upon the tails Of passing comets
is highly suggestive phenomenon. Professor
Bigelow has noticed n resemblance between
the curves of coronal strcamers and those of
the lines of force surrounding n spherical
magnet. And Pupin has produced an artificial
corona in Il laboratory by electrical means. \
good deal of other testimony might be cited
were space available. One OF the freshest bits
IS this: Mr.. Abbot. of the Smithsonian Institu-
tion. tried last May to measure the heat
radiated by the corona. This he found to be
smaller than was anticipated. Hence he
cluded that the corona "ls giving light In n
manner not associated with n high temper
'ature." 4 repetition of this observation is de-
srable but as II stands 1t offers n new hint
that the solar appendage in question is largely
an electrical phenomenon.