DOCS.
286, 287
SEPTEMBER
1911 207
bundles
of
hay
like
Heine's
ass;[7]
it
is
better
to be forced
by
fate
one way or
the other.
But
that
I
shall leave
semi-barbaric
Prague
with
a
light
heart,
that's
for
sure.
The
objections against gravitation
are
of
little
consequence.
We will
talk about that
in
ease
and
comfort
in
Karlsruhe
and
Zurich.[8]
By
the
way,
an
astronomer
from the
Berlin
observatory
has
taken
up
the
experimental
side
of the
thing
with
passion.[9]
He
even
hopes to
be able
to
measure
the
apparent positions
of
fixed stars in
the sun's
proximity
in
bright
daylight using
a
shrewd
method. But
I do not
yet
believe it.
With
best
wishes
to
you
and
your
wife,[10]
your
bird of
passage,
A.
Einstein
My
wife also
sends her best
wishes.
Kind
regards
to Mr.
Heller.[11]
287.
To
Erwin Freundlich
[Prague,
21 September
1911]
Esteemed
Colleague:
By
k
I
understand the
constant
that
enters
Newton's
law in the
following way:
force
=
kmm'
r2
The
system
of
units in
the
formula[1]
2kM
a
=
c2
A
is
of
course
irrelevant
if
c
is
measured
in
the
same system.
Is it
really possible
to
observe
stars
near
the
sun
in full
daylight,
i.e.,
in
the
absence
of
a
solar
eclipse, by
means
of
currently
available instruments?[2]
If
this
can
be
achieved,
then
you
shall
surely
be
successful in
determining
whether the
theory is
valid.
I do not
see
how
spectral decomposition
can
be
of
any use
here, since
the
sun
emits
all the
types
of
light
that the
stars
in
question
emit.
Or
are
there
enough
stars
that
have
bright
lines,
or even
no
lines,
where
the
sun
has
absorption
lines? I
am
curious
how
you
conceive
the method.
You
can
keep
the
reprint,[3]
of
course.
With
collegial greetings, your very
devoted,
A.
Einstein