504
DOC.
24
DISCUSSION OF GDNA LECTURES
Excerpts
from the
printed
versions
of
discussions
following presentations
of
papers
at
the
83d
meeting
of the Gesellschaft Deutscher Naturforscher und Ärzte
in
Karlsruhe
by
Arnold
Sommerfeld
(on
25
September
1911), by
Walther Nernst
(on
27
September),
and
by
Heinrich
Rubens and Hans
von
Wartenberg (on
27
September
1911).
Published in
Physikalische
Zeit-
schrift 12
(1911):
978
(published 15
November
1911), 1069,
1084
(published
1
December
1911).
Shorter versions of the discussion
comments to
the lectures
by
Nernst and
by
Rubens and
von
Wartenberg were published
in GDNA
Verhandlungen
1911,
pp.
94-95.
I
Sommerfeld et
al.
1911:
Discussion
following
Sommerfeld
1911b
[1]
In
his
lecture,
Arnold
Sommerfeld
conjectured
that
because Planck's
constant
has the
dimension of
an
action,
its role
in
radiation
experiments
does
not
indicate the existence of
elementary quantities
of
energy,
but of
a
universal
property
of
the
temporal
characteristics
of
energy exchange.
On the basis of
this
conjecture,
he
developed
an
analysis
of
the
absorption
of
radiation
involving
the notion of "accumulation time"
("Akkumulationszeit"),
and he
gave an
explanation
of
the
photoelectric
effect
different from Einstein's. Einstein's remark elaborates
on
the
objection
made
by
Stark
in
the
beginning
of
this
discussion.
Before
attending
Sommerfeld's
lecture,
Einstein had discussed the role of
the
time factor
in
absorption
with
Besso; see
Einstein
to
Michele
Besso, 11 September
1911.
For further
comments
by
Einstein
on
Sommerfeld's
theory,
see
Doc.
25.
[2]
Measurements of the
delay
time of the
photoelectric
effect
were performed by
Karl
Lichtenecker and Erich Marx in
Leipzig; see
Marx and Lichtenecker
1913.
Their
measurements
indicated that Sommerfeld's
theory
cannot be correct.
For
a
discussion of the
experiment as
well
as
references to
earlier
attempts
to perform
such
measurements,
see
Wheaton
1983,
pp.
187-188.
II
Nernst
et
al. 1911:
Discussion
following
Nernst
1911e
[1]In
Nernst
1911e,
on p. 978,
Walther Nernst
discussed, among
other
things,
the increase of
electrical
conductivity
of
several metals
at
low
temperatures, reporting
on
research
done inde-
pendently by
Kamerlingh
Onnes and
himself.
Nernst
reported
that this behavior
is
found for
aluminum
at
a
considerably higher temperature
than for
platinum.
He
pointed
to
a
possible
connection of
this
phenomenon
with the oscillator
frequency appearing
in
the
quantum theory
of
specific
heats
(see
Nernst 1911e,
p. 978).
[2]Kamerlingh
Onnes
was
performing
a
series
of
experiments
on
conductivity at
low
temper-
atures
(see, e.g.,
his
report to
the
Solvay Congress
on
that
subject
in Kamerlingh Onnes
1912,
1914)
of
which Einstein had learned
during
a
visit to
Leiden earlier the
same
year
(see
Einstein
to H.
A.
Lorentz,
15
February
1911).
As documented
by
his
correspondence
with
Michele
Besso,
in
1911
Einstein
was
also
working
on
the
problem
of
electric
conduction
and,
in
particu-
lar,
on
the
problem
of
alloys.
III
Rubens
and
Wartenberg
et
al. 1911:
Discussion
following
Rubens
and
Wartenberg
1911
[1]Heinrich Rubens and Hans
von
Wartenberg
measured the infrared
absorption
of
twenty–
two
gases
at five
different
wavelengths.
In the
case
of the
light
emitted from
a
quartz mercury
lamp, they
found that
its
absorption by mercury vapor
is
negligibly
small. From this observa-
tion
they
drew
the conclusion that the
light
emitted
by
the
lamp
is not
heat
radiation,
i.e.,
radiation
that
would be emitted
naturally
at
a given
temperature,
but "luminescence" radiation.
[2]In
the
printed
version of their
lecture,
Rubens and
von Wartenberg
made it clear that their
conclusion
concerning
the
nature
of the radiation emitted
by
the
quartz mercury lamp
is
problematic
because of
the
temperature
difference
between the
lamp
and the
mercury vapor; see
Rubens
and
Wartenberg
1911,
p.
1083, fn. 2.