344
DOCS.
353-355 JUNE
1917
spherically
shaped
star
clusters,
the
Milky
Way,
etc.,
where
astronomy
also
is
called
upon
to
provide
important
assistance in
testing
new
physical
theories.
Yours
truly,
E.
Finlay
Freundlich.
354. From
Max
von
Laue
Würzburg, 18
June
1917
Dear
Einstein,
With
great regret I
heard
yesterday
in
Frankfurt that
your
doctor
only
wants
to grant
you
such
a
short
stay
in Frankfurt.[1] Wachsmuth and
I
have decided
to
monopolize you
at
least for
the
evening following
the
talk, and Wachsmuth
will
probably
give
you
the details
soon.[2]
But
I
would
like
to have
you
for
a
bit
longer
and
for
once
not in
a
big
throng
of
people.
That
is
why
I
would
like to
know
the
following:
On
which train
are
you arriving,
and when do
you
have
to
leave?
Additionally,
I
have
a request:
Do
commend
our
colleague
Born
as
much
as
possible
in
Frankfurt.
This
can
be done with
a
good conscience,
of
course.
For
if all
else
fails,
I
should
like
to
try
to
swap positions
with
him;[3]
and the
only
problem
that
could
possibly
arise in
this,
as
far
as
I
can see,
lies
in
Frankfurt.
With
cordial
regards
and
hoping
that
you
will
soon
be
feeling
better,
yours,
M.
Laue.
355. From Willem de Sitter
Doorn, 20
June
1917
Dear
Einstein,
From
the
smallness of
the
relative stellar
velocities,
one can
also
actually just
draw conclusions
about
g44
and
not
about the
spatial
gij's.[1]
Actually,
nothing
can
be inferred from
the
velocities,
rather,
the
line
of
reasoning
is:
If
the
accelerations
were
not
small,
the
velocities
could
not
remain
small,
and if
the
accelerations
are
small,
g44
-
1
must be small. Let
us
imagine
that the
velocities
are
of
the
order
a;
then
if
g44
-
1
is
of
the
order
r
and
gij
+
dij
of
the
order
ß,
the
accelerations
thus
contain terms of the orders
r, r2,
Br,
a2B,
ra2,
etc.-but
not
ß
alone.
Thus
only
the
smallness of
r,
not
ß,
can
be inferred from
the
smallness
of
a
and the
accelerations.[2]