DOCS.
351,
352
JUNE
1917 341
P. S. I
shall be
away
on a
trip
to Switzerland in
July
and
August
and
September.
My
health
is
still
shaky
too.[9]
352. From Paul
Ehrenfest
[Leyden,]
14
June
1917
Dear
Einstein,
Thank
you very
much indeed for
your
detail[ed]
letter. In connection with
your
comm[ent] on
quantum
formulations,
the
enclosed
summary
of
a
calculation
made
by Burgers a
few weeks
ago
may
be of interest to
you.
I shall send
you
his
calculations
on
band
spectra
very
soon.[1]
-o-
Yesterday
during
an
intermission between two talks at
our
physics colloquium,
I
made
public
the
engagement
of
Nordstrom with
the
younger
of
the
two
van
Leeuwen
physics
students.
(Her name
is
Nelly
van Leeuwen;[2]
her older
sister,
H.
van
Leeuwen,
is
assistant
to Lorentz and
me
and
will
soon
take her
doctorate
under
Lorentz.)[3]
The
day
before
yesterday
it
was
also
a
great
surprise
to
my
wife
and
me
when
the
two
came
to
see us.
We
know them
both about
equally well,
had noticed–
even
though they
were
in
front
of
our
eyes
almost daily-nothing
in the
least,
were
extremely astonished,
but
also
absolutely pleased
without restraint.
This
woman
is
a
very capable, warmhearted,
vivacious
person
and
is
an
excellent
match
for
Nordstrom.
The
entire
big family
of
Leyden physicists
and
mathematicians
(you
know-we
all
hang
together
here
very
congenially)
is
celebrating
the
couple’s joy
merrily
and
boisterously, except perhaps
for
one
or
the other of
the
younger
ones
who
was
in
love
with
Nelly
(n
0).
It
was incidentally
very
evident
on
this
occasion in
particular
that
we
are
largely
united
here,
not
only professionally
but
also
personally. (N.B.,
in the last
few
months,
an
engagement
epidemic
has been
surging
through
our
building,
and the first
stop
is
always
to
my
wife
and
me-but
never were we
as unreservedly pleased as
this
time!)
-o-
Nordstrom
is preparing
to
write you-but
don’t wait
for
it!
Fond
greetings, yours,
Ehrenfest
Onnes and
de
Sitter
are now
much
better.[4]