362 DOCS.
366,
367
JULYAUGUST
1917
366. To Willem de
Sitter
Lucerne.
[31
July
1917]
Dear
de Sitter,
No
matter how
I
piece
it
together,
I
cannot
grant your
solution
any physical
possibility.[1]
The trouble
is
simply
linked to
the
fact
that
in
the
finite realm
(in
natural
measure)
the
guv's
assume singular
values. Let
us
base
ourselves,
for
ex.,
on
the
clearest form
ds2
=
dr2

R2 sin2
¿¡(dtp2
+
sin2
ipdp)2)
+
cos2
ßdt2.
The
energy
of
a
masspoint is
generally
mZg4v
dxv
ds’
where
m
stands
for
the
mass
constant
(mass
in natural
measure).
The
energy
of
a
point at
rest
is
thus
my/g44.
This
vanishes for
r/R
=
n/2.
For
r
=
n/2R,
the
masspoint
has
no
energy;
it does
not exist
there
at
all
anymore
but
evaporates entirely along
the
way
there. To
me
the
admission
of
such
cases
appears
to be nonsensical. This
will
always
be
true,
of
course, regardless
of how
we
may
choose
the
variables.
You
see
from
my
more physical
approach,
though,
that
I
am
incapable
of
formulating exactly (in
an
invariant
way)
the
condition
that the
fourdimensional
world has to
satisfy
in
order
to
avoid such
singularities.[2]
Would
you
consider
trying
something
in
this
direction?
Cordial
regards, yours,
A.
Einstein.
367. To
Michele and Anna BessoWinteler
[Lucerne, 1
August
1917]
Dear Michele
and
Anna,
You
looked
after
me
with such
loving
care
that
I
don’t know how to
recount
it
all.
The
operating
instructions
for
my
stomach
are
being
followed
and honored
conscientiously,
and
my
entire
lifestyle
is
medically correctly arranged.[1]
Maja
and Paul
create
a
sanatorium
as
comfortable
as
it
is
rigorous,
so
that
nothing