152
DOCS.
203,
204 APRIL
1910
/
In
order
to
be able
to
set[2]
i2
=
N.
w
N
\
l
·p,
the
square
of
the
first
term
in
the bracket
/
must be small
compared
with the
square
of
the
second term.
(This
condition
must also
be
satisfied in
order
for
the
tone not
to
be
altered.)
For
the
frequency
in
question
we
must
thus have
A?Ŧ
wCl
10;
otherwise
one
cannot set
i2
=
w
'N2N1
N1I
/
At the
beginning
of
May
I
may pay you a
short
visit in
Bern,
because there
will be
a
Naturforscher
meeting
in
Neuenburg,
and
I must
give
a
talk
there.[3]
With kindest
regards
to
you
and
your
wife,
yours,
A.
Einstein
My
wife also
sends her
regards.
[...][4]
D. Mr. Ch.!
I must also ask
you
something concerning
a
kind
of
new or
not
new
contact
spring.[5]
soldered
pin
spring
point
of
contact
(without a
jack)
You
told
me
that
this kind
of
contact
is not
new.
Please let
me
know
where these
contacts
are
being
ap-
plied,
and,
in
what
way,
if
any,
the
contact
springs
known
to
you
differ from
the
one
sketched here.
204. To
Pauline
Einstein
Zurich.
Thursday
[28
April 1910]
Dear
Mother,
This
time
I have
a
guilty
conscience
because of
my
long
silence,
the
more so
because
I
don't
know
when
you'll
receive this
letter,
since
you
are
now
in
Berlin.[1]
Healthwise
I
am
all
right
again.
I
hope
that
you
have also
recovered
completely.
The bad mood
that
you
noticed
in
me
had
nothing
to do with
you.
This must not
concern
you;
to
hammer
away
with
others
on
the
things
that
depress
or
anger
us
does not
help
in
overcoming
them. One
must
knock
them
down
alone.