DOC.
141
NOVEMBER
1915 145
141. To Wander and Geertruida de Haas
[Berlin,
before
15
November
1915][1]
My
dear de
Haases,
I
was
very pleased
with
your exquisite
little
letter,
from which
one can
im-
mediately
feel
how
happily
and
contentedly you
are
living
in
your
little
nest.
I
definitely
believe
that
you
have done
the
right
thing
with
your
decision.
23
hours
are
a
lot,
though.
But
teaching
is
very
amusing,
especially
when
facing
sturdy, unspoiled
country
children with
healthy
nerves.[2] I
believe
that
I
also
could accustom
myself
with relish to such
a
position
even
now.[3]
As far
as
I
can see,
not
much
can
be done
in the
laboratory
with
gravita-
tion. The
negative
result
on
the
independence
of
gravitational
acceleration from
matter is probably
adequately
secure.
It
would
suffice for
me,
even
without
any
experiments
with
radioactive substances whatsoever.[4]
In the
end,
because
we
can
observe
their
transformations,
these substances will
not exhibit
any
unusual
inertial
behavior.
I
am very
eager
to
see
your paper
on
the
effect.[5] I
have also conducted
ex-
periments
in which
I
reversed the remanent
magnetism by
means
of
a
condenser’s
discharge
current.[6]
But the
thing
has
not worked
until
now
because, despite
the
short duration
of
the
field
(10-3"), an
intense
vibration
of
the
rod
ensued,
oblit-
erating
the
effect.[7]
This
will naturally
be avoided with
your
method.
I hardly
believe
that
your 10% discrepancy
with
the
theory
is
real. If
it
were so,
however,
it would be
very
important. As
a
matter
of
fact,
I
still do not know
what
Maxwell
has done
on
this
subject.[8]
At
any
rate
it
is evident
here
as
well
what
a
good
nose
this
man
had!
Barnett’s comment
actually
gave
me
little
confidence.[9]
Working
analogously
with metal electrons
is
very
difficult.
But
you
are
at
the
best
location for this
enterprise,
of
course.
I
congratulate
you
particularly
on
your
lathe
and
on
its
attached
mechanic;[10]
the
thing
has
style.
Cordial
greetings
to
you, your
wife,
and
the
children and
a
happy
New
Year,
yours,
A.
Einstein.
[10]Recipient’s
note: “who
could work
only
with
the bad lathe and
not
with the
good
one.”