DOCUMENT
187 FEBRUARY
1916
257
[3]Work
at the
Royal
Prussian
Observatory
in
Neubabelsberg,
from which Einstein had
tried
to
rescue
Freundlich twice the
previous year (see
Docs. 53,54,
123,
and
160).
[4]Perhaps
Michele
Besso,
who
was
familiar with the
proofs
for
general relativity,
but
was
not
involved in
organizing
their
verification.
[5]Sommerfeld’s Munich
colleague,
the
astronomer
Hugo von Seeliger.
[6]In
Freundlich
1915a,
average
values
for
the observed
redshifts of
a large
number
of
stars
of
var-
ious
spectral types are
determined from
observations. These
averages
were not zero, as
should be
the
case
if
the redshifts
were
Doppler
shifts
(and
on
the tacit
assumption
of
a
static
universe).
Freundlich
postulated
that the residual shift
was
in fact
a gravitational
redshift
and
presented
calculations to make
this
plausible.
In his
calculations, however,
Freundlich used
an
incorrect formula
for
the relation
be-
tween the
relative
gravitational
redshift of
stars
and
their
mass
and
density.
After
having
this
pointed
out to
him
by
Hermann
Struve,
who,
in
turn,
had been
informed
by
Hugo von
Seeliger-known
for
his
categorical skepticism
about the
theory
of
general relativity; see
Hentschel
1997,
p.
30)-,
Freundlich
corrected his
error
in Freundlich 1916a. In order to maintain his earlier conclusion, how-
ever,
he had
to
use an average
star
density
that
was
five times
as large
as
the
one
used in
Freundlich
1915a. This
procedure,
and Freundlich’s weak
arguments
for
it,
were harshly
criticized
by
Seeliger
(Seeliger 1916),
who also
indicated
annoyance
at
not
receiving
credit
for
unmasking
the
error (see
Hugo von Seeliger
to Hermann
Struve, 12
January
1916,
in Kirsten
and
Treder
1979a,
pp.
171-172).
See
Hentschel
1994
for
more
historical
background.
[7]See
Doc.
2,
note
9,
for
more on
Freundlich’s
early
interest
in
general relativity.
[8]A
phrase
in the
poem
“Der Edelacker”
by
Wilhelm
Gerhard
(1780-1858),
which
retells
the
story
of
a
count,
Iron
Ludwig
(Landgraf
Ludwig
der
Eiserne)
of
Thuringia,
whose mildness in
political
affairs
was
corrected
by
the admonitions
of
a
blacksmith.
Losing
his
way
after the
hunt, Ludwig
found
shelter
in the hut
of
a
smith,
who
kept
him awake all
night
with
incessant
blows
on
iron,
accompanied
by
repeated
advice
to
stiffen his resolve; “Steel
yourself’
(“Nun
werde
hart”).
[9]See
Freundlich 1915b. See also Doc.
161,
note
7,
for
this
earlier
controversy
with
Seeliger.
[10]See
Docs. 160
and 181.
[11]Einstein
had
already
considered
light
deflection
by
Jupiter
in
Einstein
1911h
(Vol. 3,
Doc.
23),
in
which
the existence
of
gravitational light
deflection is
predicted from the
equivalence principle.
187. To
Mileva Einstein-Maric
Berlin,
Wittelsbacherstr.
13.
6. II.
16.
L[iebe] M[ileva]
Ich stelle Dir hiemit den
Antrag,
unsere
nunmehr
erprobte Trennung zu
einer
Scheidung auszugestalten,[1]
wobei wir
uns
im
Wesentlichen
an
den
Entwurf
unse-
res
Freundes Haber halten
können[2]
Ich
glaube,
dass
es
im Interesse
von uns
bei-
den
liegt,
dass
auf
diese Weise die Pflichten
und
Rechte eines
jeden
von uns
klar
festgelegt werden,
sodass
jedes
den Rest seines
Lebens
soweit
unabhängig vom an-
dern einrichten
kann,
als dies die
Sachlage gestattet.
Wenn Du mir
mitgeteilt
hast,
dass Du
prinzipiell
einverstanden
bist,
werden
sich
die Einzelheiten
gewiss zu
Deiner
Zufriedenheit
regeln
lassen. Es ändert sich durch
diese
Klärung
der Verhältnisse nichts
daran,
dass ich
es
als meine erste
und
wich-
tigste
Pflicht
betrachte,
für
meine Buben
Ersparnisse zu
machen;
in diesen
11/2
Jahren[3]
habe ich bereits
über
8000 M für sie
erübrigt.