288
DOC.
384
APRIL
1912
Let
S1
and
S2
be
two
coherent
rays coming
from
a mov.
star,
one
of
which
passes through
a
foil
B.
The
phase
difference of the
two
rays
at
E then
depends
on
the distance
B
-
E
to
the
first
order of
magnitude
since
the
wavelength
before
and
after
B
is not
the
same.
In
case (1)
the
following
is
to be
expected:
in all
directions,
the
light
emitted
by a
moving
canal-ray particle
has
the
same
wavelength
as
the
light
emitted
by
identically
constituted
particles at rest.
Thus,
the
light
should not show
a
Doppler
effect when
investigated by
means
of
a
lattice,
but
it should do
so
when
investigated by
means
of
resonance
(dispersion). (The Doppler
effect exists
then
with
regard
to
frequency.
The "starkest
man"[5]
would
probably not
believe in
either of the
two
eventualities.
Now to
your
letter,
but
you
must
excuse my brevity
because
I
am
groaning
under
a
pile
of unanswered letters.
1.
Just
go
ahead
and
translate that
paper.[6]
I'm
not
claiming any "relativity monopoly"!
All
that
is
good
is
also welcome.
You
do not have
to
send the
proofs.
2.
The
thing
about the
photochem.
effect
becomes
doubtful if the
radiation
in
question
is
not
very
weak,
because
in
that
case
the "false"
thermodynamic equilibrium
between
the
gas
and the radiation of
a
different
temperature
will,
in
principle,
not
exist;
the
absorption during decomposition
will
not
be
equal to
the
emission
during
re-formation.[7]
At least
this
is
what
I
believe.
3.
The
graphic representation
of the
kinematics
of
the
gravitational
field
seems
very
pretty.
By
the
way,
I
can now
send
you (in
a
few
days)
the
proofs
of both
papers.[8]
45)
Thank
you
for
returning
the
rel.
paper.
4.
Kleiner didn't
want to
hear of
an
appointment
for
you
at
the
University
of
Zurich,
which I
had
suggested
to
him.[9]
Weiss wrote
that
it
won't
be
possible
to
do
anything
about
your
Habilitation
until I'm
in
Zurich.[10]
Your stubborn refusal
to
acknowledge any
religious
affiliation
really bugs
me;[11]
drop
it for
your
children's
sake.[12]
After
all,
after
becoming a
professor
here,
you
could revert to this
strange
hobby
horse of
yours-the
whole
thing
would
take
only a
short
time.[13]
Let
your
wife work
you
over.[14]
Correction
of
an error
in
your
letter:
not
"My
wife and
I
have
decided,"
but
"I have
decided."
Finally,
the
Nernst
story.[15]
He
is
not
amenable
to
reason
(too
little
of
a
logician).
But it
is interesting
that
in
Planck's
mind
the
impossibility,
in
principle,
of
reaching
absolute
zero
is
an
axiom
to which
everything
else
must
yield.
Nernst himself
admits
that
his
proof is
not valid
even
from the
thermodynamic
standpoint.[16]
Thus,
a
conflict
that
can
be
fought out theoretically
does
not
exist
anymore.
Experience
will have
the last
word.
I
am
enclosing
a
letter
from
Smoluchowski.[17]
With
best
regards
from
me
and
my
family
to
you,
your wife,
and
your
little
children,
I
remain
your
comrade
A.
Einstein
Excuse
the
dirt.
It's
brown coal.