Imperial Valley press., 1923-08-30

SCIENTIST TELLS BIG AUDIENCE
-HOWTO WATCH ECLIPSE OF SUN

KS Il" N5 49+A tIs -
SAN. DIEGO, Aug. 3o-A crowd
that taxed the capacity OF tie Lin
coin school auditorium and stage
here listened to a lecture on eclipses
in general and the September 10
eclipse in particular Prof. L. G..
Hoxten, of the University of Vir-
ginia, who has come to San Diego
to observe the eclipse, explained
the phenomenon, showing pictures
of previous eclipses and the apara-
tus used in observing them, and
gave instructions as to the best
way to watch the forthcoming
eclipse and what to look for. The
lecture was given under the aus
pices of the Atheneum club.
A scientist who studies eclipses,
explained Prof. Hoxten, must be
willing to go anywhere at any time.
There are, he said, several eclipses
every year but only Il very few of
them are visible in parts of the
earth where conditions are such
that observers can both live and
work.
eff we had searched the world
over" he said, seeking place
where the conditions for the eclipse
would be ideal we could not have
chosen any place better suited to
our observations than San Diego.
1t is almost too good to be true.
We enjoyed coming here. 1t is a
pleasure TO live here. And it is
easy to work here. We have been
delighted with the interest the
people have manifested in us and
the cooperation of all concerned. -
Difficult Work
The astronomer, he explained,
must be an engineer to lay out the
positions for his instruments, a
mathematician, a photographer, a
carpenter, cement worker and Il
pick and shovel man. He then pro-
ceeded to show the results of the
hard work that he and his
colleague, Prof. S. A. Mitchell, have
put in on previous eclipses, at
Sumatra in 1901, in Spain in 1905,
and in Oregon in 1918.
The two main phases of eclipse
observation, as also of all 'astron-
omical observation, are telescope
and spectroscOpic, he said. The
telescope observations tell the po-
sitions of the stars, where we are
going, and how fast we are going
there. This branch of the science
is what enables the accurate pre-
dietion of eclipses. The spectre
scopic phase of the observation
tells the scientist what the celes-
tial bodies are made of and what
is going on there.
Prof. IloXten explained the
eclipse by showing that 10-cent
piece held at arms length from the
eye will shut out the sun, while a
dinner plate 10 feet away will do
the same thing, rs will balloon
30 feet in diameter mile away.
Thus the moon, 1000 miles in di-
ameter, produces the eclipse 240,,
coo miles away.
cit is fortunate,' he said, "that
the moon is just this distance
away. If it were further we might
never see the wonderful solal
corona or even know of its exist
cnce. AS it is there are several
eclipses, the foci of which never
reach the earth. The result is an
annular eclipse in which the outer
ring of the sun is not covered. Such
an eclipse, while interesting and
beautiful, is worthless scientifi-
cally.'
Smoked Glass Needed -.
The absolute necessity of view
ing the partial phases of the eclipse
through heavily smoked glass was
emphasized by the speaker, who
explained that if the smoked glass
is not used the eye may be in
iured and at best it will be 50
fatigued that the corona will not
be visible when totality comes. The
proper way to smoke glass is to
use Il candle, kerosene lamp, or a
burning piece of camphor gum.
The proper amount of smoke can