336 DOCS.
347,
348
JUNE
1917
347. From
Wilhelm
Wien
Würzburg, 8 Pleicher
Ring-road,
1
June
1917
To
Prof.
Einstein, Berlin, 13
Wittelsbacher
St.
Esteemed
Colleague,
While
reading
your interesting
paper
on
quantum theory
(P.
Z.
1917, p.
121)[1]
a
thought
occurred
to
me
of which
I
would
like to inform
you.
You consider
the
equilibrium
between molecules and radiation
and
come
to
the
result
that
the
balance
can
only
subsist
if
the radiation
is
emitted
from
a
particular
direction and
conveys a
kinetic moment
to
the
transmitting
molecule.[2]
This
system can never
be
complete, however,
because
the
impinging
radiation
releases
photoelectric
electrons and
these,
in
their
turn, excite
radiation.
Upon
emission
of
an
electron,
a
momentum of
the
quantity
2hv/v
is
conveyed
when
the
relation
m/2v2
=
hv
holds. On
the other
hand, upon collision,
the emitted
electron
will
transmit
momenta whose
quantities will
remain
unknown,
since
the
electron
does
not
necessarily
have to be
brought
to
rest
by only
a
single
inelastic
impact
but
can experience changes
in
direction
in
the
vicinity
of
the
molecules,
which
likewise
convey
momentum.
It
ought
to be
entirely possible
to
satisfy
the
thermal
equilibrium
condition
through
suitable
assumptions
about the
behavior of these
electrons,
without
having
to make
the
assumption
of
singly
directed
emission,
which conflicts
with
the
wave
theory of
light.
Our
last
meeting
was
very
brief.
I
hope
next
year
we can
discuss science
under
more
peaceful
stars.
With best
regards, yours,
W. Wien.
348.
To
Gustav Mie
[Berlin,] 2
June
1917
Highly
esteemed
Colleague,
If
my
state
of
health
were
better, I
could
not
have been dissuaded from
trav-
eling
to
Göttingen
for
your lectures,
particularly
since
our
colleague
Hilbert had
invited
me
to
it
very
heartily
more
than
once.[1]
It
would have been
a
great
plea-
sure
for
me
to hear
your talks,
from which
I
would have learned
more,
no
doubt,
than
from
a
mute
article. On
this
occasion,
I
have
the
urge
to
say something
to
you
for which
I
had
always
lacked
the
opportunity.
I
deeply
regretted
that
Lecher