EARLY WORK ON QUANTUM HYPOTHESIS 147
VI
The
precise
circumstances
of Einstein's invitation
to
address the
eighty-first
meeting
of
the
Gesellschaft Deutscher
Naturforscher und
Arzte
in
Salzburg are
unknown. The
Ge-
sellschaft, founded in 1822 to
promote
the
unity
of
all natural sciences
(including
medi-
cine)
and all
German-speaking
scientists,
had
over
three thousand members.[92] Einstein
attended the
Salzburg meeting,
the first international conference at which he
spoke,
as an
"honored
guest" ("Ehrengast")
of
the Deutsche
Physikalische
Gesellschaft.[93]
While
in
Salzburg,
he met
many
of
the
leading figures
of
physics
for the first
time.[94]
His talk
was
given
to the
Gesellschaft's "Section
for
Physics, including
instruments and scientific
pho-
tography" ("Abteilung
für
Physik,
einschl. Instrumentenkunde und
wissenschaftliche
Photographie")
on
the afternoon
of
21
September.[95]
According
to
one
report,
Einstein's
"broadly
conceived
lecture"
("grossangelegten
Vortrag")
at
Salzburg was
"the
main event
of
the
physics
section
of
this
conference of
scientists"
("das
Hauptereignis
der
physikalischen
Sektion dieses Naturforscher-
tages").[96]
Einstein
opened
the session with
an
address
"On
the
Development
of Our
Views
Concerning
the Nature and Constitution
of
Radiation."[97]
Einstein
1909c
(Doc.
60),
received
shortly
after the
meeting,
is
the written version
of
his talk. It
is
ostensibly
merely a
review
of
his work
on light over
the
preceding
years.[98]
Yet it
is
much
more:
it
is the first
synthetic
account
of
the
profound
transformation
in
the
concept
of
light
brought
about
by
the
theory
of
relativity
and the
quantum hypothesis,
and
of
the
profound
impli-
cations
of
this tranformation for the
development
of
physics.
Einstein maintained
that
the
long-held
ether
hypothesis
had,
by
1909,
been reduced to
"a
superseded
position"
("ei-
nen
überwundenen
Standpunkt");
and that
light, long regarded as completely
described
by a wave
theory,
possessed properties
that
were
understandable
only
from the
standpoint
of
an
emission
theory.[99]
He elaborated
on
both claims for
an
audience that
was favorably
disposed
toward the first
assertion,
but still
skeptical
of
the second.
Einstein focused first
upon
the
problems
of
the
electrodynamics
of
moving
bodies, and
the resolution
by
the
relativity principle
of
the
previously "extremely unsatisfactory"
("höchst
unbefriedigende")[l00]
situation
in
this field. The elimination
of
the
ether
implies
[92]
See
Verhandlungen
1910,
part
2,
p.
12.
[93]
Recruitment
Commission for the Chair
of
Mathematical
Physics
to
Members
of
the Philo-
sophical Faculty, University
of
Prague, 21
April
1910
(Cz-Ar,
Einstein
dossier).
[94]
Einstein
reported
that he met
for
the first
time
Planck, Wien, Rubens,
and
Sommerfeld,
of
whom he
was particularly
fond
(Einstein
to
Jakob Laub,
31
December
1909;
see
also Ein-
stein
to
Arnold
Sommerfeld,
29
September
1909).
[95]
See
Versammlung
1909a,
part
2,
pp.
26,
41.
[96]
Recruitment Commission to
Philosophical
Faculty, University
of
Prague
(see note 93).
[97]
According
to
Verhandlungen
1910,
part 2,
p.
41, the title
of Einstein's
lecture
was
"On
the
More Recent Transformations Which Our
Con-
ceptions
of the Nature
of
Light
have Under-
gone"
("Über die
neueren
Umwandlungen,
welche
unsere Anschauungen
über die Natur des
Lichtes erfahren haben"). The
text
of
Einstein
1909c
(Doc. 60)
was
also
printed
in the
Physi-
kalische
Zeitschrift.
[98]
Einstein failed
to
send
a copy
to Laub
"be-
cause
it contains
nothing
new"
("weil
sie nichts
Neue[s]
enthält")
(Einstein
to
Jakob
Laub,
31
December
1909).
[99]
See
Einstein
1909c
(Doc. 60), p.
482.
[100]
Ibid.,
p.
486.