DOCS.
438,
439
JANUARY
1918 445
The
nonsense
C
=
0
already
haunts
an
earlier
paper
of
de Donder’s.
The
factor
1/4
in
(1),
incidentally,
is
closely
connected
with
it.[6] Actually,
1/2
should
appear
there. In
short,
we
have here
a genuine
counsel of
confusion.
To whom should
I
write
about the
instrument?
I
shall do
so
as
soon
as
I
have
the
address. I
am
returning
to
you,
with best
regards, your
report
as
well
as
the
famous notice
by
de Donder.
Yours,
A.
Einstein.
I
shall
see
that
we
put
forward
your
contract for resolution
on Thursday.[7]
I
think
you
should
say
in
your
report
that the
author’s
equations
are
not
only
not
equivalent
with
mine
but
not
even
possible
on
their
own.
For it
ought
to
be known
that
you
discovered de Donder’s
error.
I
was
very pleased
that
you
spotted
the
crux
of
the
problem.
I
have left to Lorentz
the
exact
manner
of
correction in
the
Amsterd.
Academy
Reports.
It
is
best that the author
submit
a
correction
himself.[8]
439. To
Rudolf Förster
[Berlin,]
17 January 1918
Esteemed
Colleague,
First
of
all,
I
sincerely apologize
for
my long
silence.
But
I
have been
lying
in bed for almost
4 weeks
already, owing
to
a
refractory
stomach ulcer
and
am
very
much
hampered
in
everything.
Your
letter[1]
was
extraordinarily interesting
to
me
and confirmed
my
opinion
that,
with
you,
we
are
dealing
with
a
born
theoretician.
You must not
take
your
industrial
slavery
too much
to
heart.
I
also
was one
of those
during
my
best
years,
as
an
employee
of
the
Swiss
Patent
Office.
My genuinely original
ideas all
stem
from
that
time,
for
all too
soon
does
one
become
an
avuncular old
boy,
and
the little
fount of
imagination
dries
up.[2]
Permission
to publish
purely
scientific ideas
will
surely
be
granted
you
despite your employment
contract,
that
I
guarantee you, especially considering
that
Krupp is
very positively disposed
toward all scientific
endeavors.[3]
Now
to
your
various affairs.
First
to
what
I
did not
grasp.
I
do not
understand
why
the
condition
B12,34
= B13,24 =
B14,23
=
0
suffices
for
the
feasibility
of
the
line element
Egiidx12,