402
DOCUMENT 307 MARCH
1917
and the cellist
Raphael
Lewinowitsch.
Communication from BasBulaneck’s
daughter,
Zurich; see
also Einstein to Conrad
Habicht,
11
August
1910
(Vol. 5,
Doc.
219).
[2]Walter
Dällenbach.
[3]Most
probably,
Ismar
Boas
(see
Doc.
309).
[4]Heinrich
Zangger was
sending monthly
packages
from Switzerland
(see
Doc.
309).
[5]Eduard
had been
suffering
from
a lung
inflammation with
high
fever since the
beginning
of
the
year
and had been
bedridden for
three months
(see
Mileva EinsteinMaric
to
Helene
Savic,
ca.
3
July
1917,
Milan
Popovic,
Belgrade [75 088]).
[6]EinsteinMaric had been
diagnosed
with tuberculosis
in late
August
1916
(see
Doc.
251).
Con
temporary
medical
orthodoxy
suggested
that
children
afflicted with scrofula
were offspring
of
tuber
cular
parents,
lacked
immunity
to disease, particularly tuberculosis,
and suffered from chronic catarrh
and
middleear
infections
(see, e.g., Enzyklopädie
der
praktischen
Medizin,
1909
edition).
[7]Einstein
1917a
(Vol.
6,
Doc.
42).
[8]Einstein 1917b
(Vol.
6, Doc.
43).
[9]The
number
below is the result
of
Einstein’s
calculation
of
the radius
of
his
spherical
universe
(see
Doc.
298,
note
6,
for
further
discussion).
[10]Consider
the triangle formed
by
the
position
of
some
star
S
and two
points A
and B from which
the star is
(imagined
to
be) observed.
A
and B
can
either
be two
points
on
the orbit of the
earth
six
months
apart or
one can
be
a
point on
the
orbit while the
other
gives
the position
of
the
sun.
With
the
help
of
this
triangle SAB,
parallax
is defined
as
Jt

(a
+
ß),
where
a
=
ZSAB
and
ß =
ZSBA
.
In
the
spherical spatial
geometry
of
Einstein’s
cosmological model,
this
quantity
can
become
negative.
This
can
easily
be visualized if
one
of
the
spatial
dimensions
of
the model is
suppressed,
in which
case
space can
be
represented
as
the surface
of
an
ordinary sphere
in 3dimensional Euclidean
space.
Consider
three
great
circles
on
this
sphere,
the
one through
the chosen
points
A
and
B,
an arbitrary
one through A,
and
another
arbitrary
one
through
B.
Suppose
there is
a
star
at
both pointscall them
S and
S' where
the
latter
two circles intersect.
Light
can only
travel from
S
or
S'
to
A or
B
on
these
two
great
circles.
Consider
the
angles
a
=
ZSAB,
ß
=
ZSBA
,
a'
=
ZS’AB and
ß's
ZS'BA
on
the
sphere
(a
+
a'
=
ß +
ß'
=
n
).
Two
points
on
a
circle
divide
that
circle into two
segments.
All sides
of
the
angles
just
mentioned
are
taken to be the
shorter
one
of
a pair
of
such
segments.
If
the
points
A, B,
and
S
are on
the
same
hemisphere (which means
that
S'
will
be
on
the
other),
and
one
considers
light
that takes the
shortest
path
from
S or
S'
to
A or
B,
both
a
and
ß
will be less than
tt/2,
whereas
both
a'
and ß' will be greater than
n/2
.
The
parallax
will therefore be
positive
for
the star
at
S,
but
negative
for
the
one
at
S'.
[11]See
Einstein 1916n
(Vol. 6,
Doc.
38),
in which it
is
shown that radiation
processes
are
directed.
This is
presumably
the
paper
that
was
recently sent to Walter Dällenbach
and Besso
(see
Doc.
299).
See also Einstein’s comments
on
it
to Besso in Doc. 251.
[12]One
recent
example
of
intractibility
was
the decision of
the German
high
command to
resume
unlimited submarine warfare at the end
of
January.
307.
From Friedrich Adler
Wien VIII
Alserstr
1,
den 9. III. 1917
Lieber
Professor Einstein!
Meine Studien
über
die
Grundlagen
der
Physik,
die ich
vor
7 Jahren
abgebro
chen
hatte,
habe ich
nun
in
der mir reichlich
zur Verfügung
stehenden freien
Zeit
wieder
aufgenommen.[1]
Ich
beabsichtigte
in einem Buch meine
bisherigen ge
druckten
und
ungedruckten
Aufsätze
über
Mach zusammenzufassen
und
sie nach
verschiedenen
Richtungen
weiter auszubauen. Die Arbeit
war
schon ziemlich weit
gediehen
als ich
an
das
Kapitel
Relativität
gieng.
Da
passierte
mir
nun
etwas
ganz
Unerwartetes.