494
DOCS.
479,
480 MARCH
1918
energy
=
const.
densely throughout,
that
is,
it
traverses
any
chosen
area
of
this
hypersurface
however small
it
happens
to be.
I
obviously
cannot
prove
at all
whether
ergodic systems
in
this
sense exist,[1]
but
I
assume
it
for the
moment
pending proof
to the
contrary,
and
I
believe
that the
statement in
the
above
equation is
not at variance with the
wave
theory
of
equation
cannot be
applied
to
black-body
black-body
is
not
ergodic.
But
now
I
must
give
you
a
sharp
rebuke, namely,
that
you
did not
impart to
me
that
your
doctor
prescribed you
not to
go
out for
longer
than
a
1/2
hour!
How
much
it
pains
me
to think that
you
to
commit
a
breach of
the
holiest of
your
laws. So
from
now
on,
I
shall
think
of
it
a
bit
more.
I
shall
keep
the
surviving beneficiary question
in mind
and
report
to
you
it
later.[2]
Cordial
regards, yours,
Planck.
480.
To
Felix Klein
[Berlin,]
13 March
1918
Highly
esteemed
Colleague,
It
was
with
great pleasure
that
I
clear and
elegant
ex-
planations
on
Hilbert’s first
note.[1]
However,
I
do not find
your
my
formulation of the conservation
laws appropriate.
For
equation
(22)
is
by
no
means an
identity,
no more so
than
(23); only
(24)
is
an identity.
The
conditions
(23) are
the mixed form of
the
field
equations
of
gravitation.
(22)
follows
from
(23)
on
the
basis of
the
identity
(24).[2]
The relations here
are
exactly analogous
to those for nonrelativistic theories.
In
my view,
the formal
importance
of
the
tvo’s
consists
precisely
in
that
they
occur
next
to
the
Evo’s
in
equations (22),
which
are
valid
independently
of
the
choice of
coordinate
system.
Their
physical importance[3]
is not
only
that
they
give,
together
with
the
Tvo’s,
the
conservation
laws,
but
also
that
(23)
permits
an
interpretation
that
is
entirely analogous
to Gauss’s law
div(S
=
p or
ƒ
BndS
=
ƒ
pdr
in
electrostatics. In
the static
case, you
see,
the
number of
“lines
of
force” running
from
a
physical
system
into
infinity
is,
according
to
(23), only
dependent
on
the
3-dimensional
spatial
integrals
fCK
+
Odv,
Previous Page Next Page