114
DOC.
153 MAY 1909
quantity
related
to
electrons
to
occur
in
equations
for the
free ether. It
seems
to
me
more
plausible
that
h
is
a
constant of the
ether that
is independent
of
s.
Please
forgive
me
for
having
made
such
great
demands
on
your
time
and
patience.
I
intend
to
publish
a
more
detailed formulation of
the
ideas
developed
in
my
Rome
lecture,
together
with
some
additional considerations
along
the
lines
indicated
above,
in
the
Annalen
der
Physik,[16]
and
I
would
very
much like
to
hear
your
opinion
about
the
views I have
expounded.
In
conclusion, permit
me
to
say
how
glad
I
am
that these
problems
of radiation
theory
have
given me
a
chance
to
enter
into
a
personal
relationship
with
you,
after
having
admired
your
papers
for such
a long
time.
Respectfully
yours,
H. A.
Lorentz
I
would like
to
touch
briefly
upon two
additional
points.
1.
If
one
drops
the
hypothesis
of
light
quanta,
then the
way
in which
one
probably
must
conceive
of
photoelectric phenomena is
that the ultraviolet
rays
exert
a
releasing effect,
as a
result of
which
the electrons
leave
the metal
with velocities
they
already possessed
in
the interior of the
body.[17]
The
kinetic
energy
of
the
electrons
escaping
the metal
is
of the
order of
magnitude
of
the
kinetic
energy
that
they possess
on
account
of thermal
motion
(of course,
it
is
several times
larger).
As
regards
the
correspondence
between
this kinetic
energy
and the
energy
element
hv, it
can
be
explained
to
some
extent
by
the
circumstance that the
value
of hv for
a given category
of radiation
(cf.
Planck,
"Wärmestrahlung,"[18]
p.
161)
equals
about
3.3
x
3/2
kT,
if T
denotes
the
temperature at
which
the
radiation
curve
has its maximum
at
the
wavelength
corresponding to
v.
2. Earlier,
when
I
still
hoped
to
be able
to
derive the law
of radiation
from
the
unmodified electron
theory,
I thought
that
Xm
(see
the abovementioned
page
in
Planck)
must
be
determined
by
the
properties
of
the
electrons.[19]
Since
Xm
must
be
inversely
proportional to
the
temperature, I
came
to
expect a
relation
such
as
u
where
s
is
a
numerical
coefficient,
R
the radius of the
electron,
u2
the
mean
square
of
the
velocity
of
an
electron
at
the
temperature chosen,
and
c
the
velocity
of
light.[20]
But
because
s
would have had
to have
the
value
800,[21]
I
attached
little
importance
to this.
It
is noteworthy
that the
above
equation is
identical
with
your
proposition
that
h
agrees
Ģ2
with

in
order of
magnitude.
c
For
it follows from
my
equation,
if
m
is
the
mass
of the
electron,
and since
1
mu2
=
3
kT,
that
2 2