DOCS.
478,
479
MARCH
1918 493
met
with
approval.[2]
Since the matter is
pressing
now
and
I
would
like
to initiate
all
the
formalities,
I
request
information
on
the
following
points:
1)
Have
you
discussed
the
matter with Planck
himself,
and does he
agree
with
April
19?
2)
What
are
the titles
of
the talks:
(a)
Einstein,
(b)
Laue,
(c)
Sommerfeld
[I
can clarify
the
matter with
Warburg][3]
and
in what
sequence
are
the
speakers
supposed
to
present
their
talks?[4]
3)
Do
you
have
any
particular
wishes
regarding
the invitation
cards
(I
think the
usual
format
could be
retained)
and
the
persons
and associations
to
be invited
(I am
considering sending 10
invitation
cards with
a
letter
to each of
the
affiliated
organizations:
the
Electrot[echnical]
Assoc.,
Assoc.
of
Eng[ineers],
Chemical
Society, etc.)?
4)
What
time
of
day
(I am
likewise
thinking
of
a
1/4
to
8)?
Please
be
so
kind
as
to
treat
this
matter
as
extremely urgent
now,
otherwise
our
celebration will fall flat.
I
also
especially request
that
you clarify everything
with
Laue
and
Sommerfeld.- I
am
reachable
by telephone
in
the
usual
way
at
the
R[eich]
I[nstitute][5] (Wilhelm
5515).
I
am
also
happy
to
come
and
see you,
if
desired.
But
now
please, hurry, hurry,
hurry!!!
With
cordial
regards,
yours very truly,
Scheel.
479. From Max Planck
Grunewald,
12
March
1918
Dear
Colleague,
It
gives me no
peace:
Before
we
meet
again,
I
must rid
myself
of
something
while also
thanking
you very
much for
the
suggestion
for
improving
the
formula-
tion of
my (current)
views.
I
consider
the
equation: Entropy
=
k
.
log
number
of
complexions
as always
valid for
an “ergodic”
system
of
a
very large,
but
finite number
N
of
degrees
of freedom.
I
call
a
system ergodic
if
in
the 2Nth
dimensional
phase
space
of
the
outwardly completely
closed
system every
path
in
the
phase space
(line connecting
temporally
consecutive
phase-space points)
fills
the
hypersurface