134
DOCS.
178,
179
SEPTEMBER
1909
If the
current
is
large
compared
with
the usual saturation
current
(i0
=
n0e),
then
eßl is
negligible
in
comparison
with
eal
= e2ßl,
so
that
the second term
of
(4)
drops
out.
One
then
finds from
(4) by
substituting
the
values
/ \
a
i =
i
si
\
1
-
e ·o
/
0
or
for
the fluctuation of the
strength
of
current
/
A*
=
i2s
\
i
\ 1
-
e
0
/
0
If
one
does
not
neglect
the
term indicated,
then
one gets
/
A*
2
_ l0E
·k\
l-e
V
·2
1
a
i0
s
j
io
So
you
see
that the result
differs
substantially
from
that
of
your
argument.
I
am
curious
how it
compares
with
the
experimental
results.
It
is interesting
that here
too the
geometrical
relationships drop
out
of the
results.
Cordially,
A.
Einstein
Give
my
best
regards
to Mr.
Stark
and
your
family.[6]
179.
To
Arnold
Sommerfeld
Bern,
29 September
1909
Highly
esteemed Professor
Sommerfeld:
I
cannot
refrain
from
conveying
to
you my special
thanks for
your
great
kindness.
I
will, especially,
never
forget
how
you
looked after
me
Thursday
evening.[1]
By
the
way,
it
turned
out
that
I had
merely
a
slightly
upset stomach,
which
I
have
pampered
somewhat
by living a
regular
life.-[2]
Now I
understand
why your
students
like
you
so
much! Such
a
beautiful
relationship
between teacher
and
students
is
surely
unique.[3]
I
will strive to
emulate
your
example.[4]