DOCS.
446,
447
JUNE
1913 339
446.
To
Arthur Schidlof
[Zurich,]
17
June
1913
Dear
Sir:[1]
Naturally,
I
too
have
occupied
myself intensely
with
the
question
addressed
by you,
whether the
general
radiation formula
can
be
obtained
by
the
route
currently pursued.
But it
seemed
to
me
that the
improper
therm.
equilibrium
loses its
meaning
in
the
case
of
finite
radiation
densities.[2]
Unfortunately,
serious
objections
must be
raised
against your
way
of
handling
the
problem,
only
two
of
which I shall
point
out.
1.
It
is not
permissible
to set
the radiation
density
in
the
gas
space equal
to
zero,
even
if
the
gas can
be
considered
"black,"
which
is
always possible
to achieve with
sufficiently
great
expansion.
2. The
assumption
that the
amount
of
heat
released in
the heat reservoir with
RT
2.
You
set
Pg =
a (universal
constant).
This
cannot
be
done
even
for
regular
thermodynamic
equilibrium.
Because
at
a
given
T,
I
can
still
freely
choose the
pressure
pg
of the reaction
mixture.
The
route
chosen
by you
does
not
seem
feasible to
me,
but
your
confidence
is
contagious.
Perhaps
it will
nonetheless
prove
possible
to work out
the
case
of
improper
thermodynamic equilibrium
even
for finite
radiation
density.
With
collegial greetings,
I
remain
yours,
A.
Einstein
447.
To
Jost Winteler
[Zurich,
23
June
1913]
Dear
Prof.
Winteler,
Michele left
a
few
days
ago
for
Trieste,[1]
because
he
had
to
attend
a
business
meeting.
It
is
not
certain that
he will
come back,
because he suffered here
from
a
stubborn intestinal catarrh. But
now
he
seems
to be well
again.
I
doubt
that
Michele
knows
Uncle
Paul's[2] whereabouts;
at
least
he
never
talked about
it.
But
Rosa[3]
will
certainly
be able to
give you
this
information.
Please
do
drop
in
to
see
me
if
your path
should
lead
you
to
Zurich.
I remain,
cordially,
your
Albert