532
DOCS.
511,
512 APRIL
1918
an
equatorially
distributed
fluid.
But
your
calculation[5]
immediately yields
the
following
asymmetrical case,
which
I
show
with
a figure:[6]
void
fluid
of
constant
density
The
relevant
formulas
are:
mass-point
for
I:
1/h2
=
1
- A/6r2
for II:
1/h2
=
1+2M/r-2u0+A/6r2.
The
boundary
condition
M=~r~
is
exactly
the
same as
in
your case,
whereas M
is
the
mass
of
a
real
point mass.[7]
Evidently,
for
this
M,
one can
also
substitute
an
extended
homogeneous
fluid.
It thus
seems
that
no
grounds
are
provided
for
space possessing
the
connec-
tivity properties
of
elliptic
geometry.
With
cordial
regards,
I
am
yours very truly,
A.
Einstein.
I
hope you
have received
my
postcard,[8]
in which
I reported to
you
more
exactly
the
objection bothering
me
with
regard
to
your
new
theory. (Objective meaning
for
ds,
not
just
for
the ratios of different ds’s
originating
from
one
point.)
512. To
Hermann
Weyl
[Berlin,]
19 April 1918
Dear
Colleague,
Another letter from
that
Einstein! This time
I
must
give a
complete
report
on
the
submission of
your
article;[1]
for
a
difficulty
has arisen which
I
have unfor-
tunately
not been able to master
until
now.
A
week
ago
yesterday
I
presented
the
paper
at the
class
meeting.[2]
I
sketched
the
train of
thought,
first from
a purely geometrical
point
of
view,
and
then
its
application
to
the
theory
of
relativity.
At
the
end
I
also described
my
objection
to it,
which
you already
know.
(In
my view,
ds
itself
has
physical
meaning.)[3]