The San Francisco call., 1897-12-26


Leuschner, in charge of the OBJ
servatory at the State University
at Berkeley, are of interest, as he is a
man of clear perception, whose name
as careful Investigator has long been
known in scientific circles. He says:
In explaining solar phenomena only
such laws can be applied as are in ex-
istence on the earth. The problem of
the physical constitution of the sun
would be solved as soon as we could
explain all phenomena by these laws.
The conditions of temperature and
pressure on the sun are so different
from those on the earth that the laws.
may apply to the sun only approXi-
mately.
"A great many solar theories have
been advanced. OF the older ones,
none has been entirely satisfactory, as
has been shown by recent observa-
tions.
'The more recent solar theories may
be grouped into three distinct classes:
Mechanical theories, electrical theories,
optical theories.
The most prominent mechanical
theory is that of Professor Schaeberle,
the well-known astronomer of the Lick
Observatory. Professor SchaeberIe con-
siders that the changes on the sun rep
resent not merely optical phenomena
for example, such as accompany cleo
trical discharges-but he produces
direct evidence that the sun is con-
tinually ejecting enormous quantities
of material particles of matter with
very great velocity. By ingeniously
combining with the eruptive motion of
these particles their angular motion,
due to the rotation of the sun, he sue
ceeds in explaining every class of solar
phenomena. I have no doubt that the
more this theory be studied by astron-
omers the more supporters it will gain.
Electrical theories have been ad-
vanced by a large number of astron-
omerS in recent years. According to
them the sun is situated in a magnetic
field extending far beyond the earth.
Solar as we'll as other phenomena, as
for example the Aurora Borealis, are
supposed to be due to electrical and
magnetic forces.
quite startling theory is the opti-
cal theory of Dr. August Schmidt,
Stuttgart, which has recently been fur
ther developed by DR.. KnOpf, Jena.
Schmidt maintains that, excepting per-
haps a central nucleus under great
pressure, the sun is merely a ball of
gases without any definite surface
whatsoever and that the density of the
gases diminishes gradually from the
nucleus to outer space. The disk of the
sun as we see it in the sky is therefore
only an optical illusion, the observed
edge of the sun being produced by re-
fraction. Improbable as this theory
seems in the face of what we actually
see in the telescope and the spectro-
scope. it must be said in justice to its
promoters that their conclusions are
based on logical reasoning and through
mathematical Investigations.
LAS said before, Professor Schae-
berle's mechanical theory seems to
come nearer to the truth than any
other theory thus far advanced. Dur
ing the last few years tremendous
progress has been made in the methods
of studying and interpreting solar phe-
nomena, especially through the intro
duction of the spectre heliograph by
Professor Hale, now director of the
Yerkes Observatory
1.-THE next few years will probably
considerably increase our understand
ing of solar phenomena. The great
Yerkes telescope has already proven it's
usefulness in this direction, as Pro-
| fesor Hale announces that it has re-
vealed so many new lines in the spec
trum of the chromosphere that an i'm
mediate revision of the same will be
| pecaSSarv