206
DOCUMENT 153 NOVEMBER 1915
ALS
(SzZZa).
[81
178].
[1]This
letter is
dated
on
the
assumption
that it
was
written the
Friday
between
Einstein’s
anticipa-
tion
of
a
rendezvous
with his
son (Doc. 150)
and
his decision
not to visit Switzerland
(Doc. 155).
[2]Zangger
had
been
suffering
from “heart
disease”
(“Herzerkrankung”)
since 1913
(see
Heinrich
Zangger to Heinrich
Mousson, Regierungsrat,
Canton of
Zurich, 31
October
1918, SzZSa,
U 106
c
.3 (62)).
[3]Presumably
a
reference
to
Robert Heller’s
inability to
retain his
position
as Zangger’s
Assistent
(see
Doc.
84).
[4]Romain
Rolland,
whom he had visited with
Zangger
in
mid-September
(see
Doc.
118, note 2).
[5]Perhaps
Klein, Fr. 1915,
which discusses the United States and its
relationship to
the hostilities
in
Europe.
[6]See
Einstein
1915f-1915i
(Vol.
6,
Docs.
21, 22, 24,
25),
submitted to the Prussian
Academy on
4,
11, 18,
and 25
November,
respectively.
[7]See
Einstein 1915h
(Vol.
6,
Doc.
24).
[8]It is
not
clear
how Einstein arrived
at
the observational value he
gives
here
(see
Earman
and
Janssen
1993, pp.
131-132,
for
a discussion).
[9]See
Freundlich
1915a
and Doc.
59, note
2.
[10]The earlier
value
was
first derived
directly
from
the
equivalence
principle
in Einstein 1911h
(Vol.
3,
Doc.
23).
[11]A
reference to David
Hilbert,
who had
incorporated
Einstein’s
gravitational theory
into
a
unified field
theory
of
gravitation
and
electromagnetism.
See Doc.
140, notes 3
and
5,
for
a
discussion
of
this
theory.
Einstein attributes
the
expression
to Max
Abraham,
who
was given
to
“cheeky
sarcasm”
(“über-
mütige
Sarkasmen.” See Einstein to Alfred
Kleiner, 3
April
1912
[Vol.
5,
Doc.
382]).
[12]The
suggested
site
of
a
rendezvous
(see
Doc.
150).
[13]The
first
news
that
he
was being
considered for
election to the council
reached
him in the
second
half of October
(see
Doc.
131).
The
council
was an organ
of
the
Central
Organization
for
a
Durable
Peace,
which
was
in
turn
an
offshoot
of
the Dutch Anti-War Council.
[14]Elsa
Einstein.
[15]Ilse
Einstein.
[16]Rudolf
and
Fanny
Einstein.
153. To
Arnold Sommerfeld
Berlin. 28. XI.
[1915][1]
Lieber
Sommerfeld!
Sie dürfen
mir nicht
böse
sein,
dass ich
erst
heute
auf
Ihren
freundlichen und
in-
teressanten
Brief
antworte. Aber ich hatte im letzten Monat eine
der
[a]ufregend-
sten,
anstrengendsten
Zeiten meines
Lebens,
allerdings
auch
der
erfolgreichsten.
Ans Schreiben
konnte
ich nicht denken.
Ich erkannte
nämlich
dass meine
bisherigen Feldgleichungen
der Gravitation
gänzlich
haltlos waren! Dafür
ergaben
sich
folgende Anhaltspunkte[2]
1)
Ich
bewies,
dass das Gravitationsfeld
auf
einem
gleichförmig
rotierenden
Sy-
stem den
Feldgleichungen
nicht
genügt.[3]
2)
Die
Bewegung
des Merkur-Perihels
ergab
sich
zu
18" statt
45"
pro
Jahrhun-
dert[4]