422
DOCS.
413,
414 DECEMBER
1917
In
consequence
of
this
manner
of
deduction,
one
could
just
as
well
conclude
as
follows: No
curve
exists
according
to the
equation
x2
+
y2
=
R2;
because since
the
right-hand
side of the
equation
is
independent
of
x,
the left-hand
side also must
be!
De Donder
unfortunately
already erroneously
asserted
the
vanishing
of
C
in
an
earlier
paper,
which assertion
can
only
be
the
case
with
vanishing energy
scalar
T.[6] The
energy
scalar
does not vanish
for actual
matter,
however.-
I
am
constantly
very depressed
about the
endless
tragedy
we
must
witness.[7]
Even
the habitual
flight
into
physics
does not
always help. Surely
it
is
the
same
for
you
as
well.
My
health
is
not
the
best either.
Cordial
regards
to
you
and
your
wife
as
well
as
to Mr. and Mrs. de
Haas,
yours,
A. Einstein.
414. From
Max
von
Laue
Würzburg, 19
December 1917
Dear
Einstein,
The
event,
which Planck had announced to
me
in October
as
forthcoming
and which
you
now
report to
me as
having
come
to
pass
is,
of
course, extremely
welcome.[1] I just
don’t
know
what
use
I
can
draw from it before
my
transfer
to
Berlin
has been
secured.[2]
And for
that
reason
I
am
also unclear
about what
more
I
should
write
you except
that
I would
very
much
enjoy conducting ex-
perimental
investigations
with
X
rays
on
crystalline
structures and would
like to
apply
the
support
of
this
new
foundation toward this
end.[3]
All
specific
details
would
probably
have to be
delayed
until
my
future
has otherwise become clear.
Otherwise,
I
am,
with most cordial
regards,
yours,
M.
von
Laue.