144 EARLY WORK ON
QUANTUM
HYPOTHESIS
V
Einstein maintained that his
analysis
of Planck's
law showed the need to
modify
the foun-
dations
of
both
electrodynamics
and mechanics. In
early
1908 he wrote:
"I
believe
more-
over
that
we are
still far from
having satisfactory elementary
foundations for electrical and
mechanical
processes"
("Ich
glaube übrigens,
dass wir noch weit davon
entfernt
sind,
befriedigende
elementare
Grundlagen
für die elektrischen und mechanischen
Vorgänge
zu
besitzen").[66]
Most
leading
theoreticians, however, were
still
not
even
convinced
of
the
need
to intro-
duce
energy
quanta.[67]
Doubts about the
validity
of
the
equipartition
theorem
were
still
expressed.[68]
In
1906 Planck
attempted
to invalidate
the
ergodic assumption underlying
the
equipartition
theorem
by introducing
a
lower
limit to
the size
of
phase space
cells
of
equal
probability,
their size
being
fixed
by
the
quantum
of action
h.[69]
Another obstacle
to
acceptance
of
the
quantum hypothesis was
the
attempt
to
defend the
validity
of
the
Rayleigh-Jeans
law.[70]
H. A.
Lorentz,
universally recognized as an authority on
theoreti-
cal issues,
originally hoped
to
prove
that the
equipartition
theorem
simply
does not
apply
to matter-free
radiation.[71]
He demonstrated
just
the
opposite,
however, in
Lorentz 1908a,
arriving
at the
Rayleigh-Jeans
law and
calling
for
new experiments
to decide
between
it
and
Planck's
law. His
paper prompted a vigorous
discussion
of
the radiation
problem
in
the
pages
of
the
Physikalische Zeitschrift.
Lummer and
Pringsheim emphatically
reiterated
that
experiment
had
already
decided in
Planck's
favor,[72]
Jeans defended his
position on
equipartition,[73]
and Walter Ritz asserted that the exclusive
use
of
retarded
potentials
would
restrict
the
equipartition
of
energy.[74]
Lorentz 1908b
accepts
the
criticism of
the
experimentalists,
admitting
"that
a
derivation
of
the radiation laws from the electron the-
ory
will
hardly
be
possible
without
a profound
modification
in
the foundations
of
the lat-
ter"
("daß
eine
Ableitung
der
Strahlungsgesetze aus
der
Elektronentheorie
schwerlich
ohne
tiefgehende Änderung
ihrer
Grundlagen möglich
sein
wird").[75]
Lorentz's
statement
sion
of Einstein's
work
on specific
heats and its
reception,
see
Klein
1965;
Kuhn
1978,
pp.
210-
220;
Pais
1982, chap.
20; and
Mehra and
Re-
chenberg
1982,
pp.
113-136.
[66]
Einstein
to
Arnold
Sommerfeld, 14
Janu-
ary
1908. See the
Introduction,
pp.
xxi-xxix,
for
further
discussion
of Einstein's
search for
"satisfactory
elementary
foundations."
[67]
Ehrenfest
is
a noteworthy exception.
See,
e.g., Ehrenfest
1906.
[68] See,
e.g.,
Rayleigh
1905a,
1905b. For
a
discussion
of
earlier doubts,
see
Brush 1976,
vol.
2,
pp.
356-363.
[69]
See
Planck
1906c,
pp.
154-156, 178.
Planck's
attempt
is discussed in the editorial
note,
"Einstein
on
the Foundations
of
Statistical
Physics,"
p.
49. Planck 1906c
is
further
discussed
in Kuhn 1978,
pp.
114-134, and
Jungnickel
and
McCormmach
1986b,
pp.
265-
268.
[70]
For
example,
Jeans
argued
that the law
does
not
hold
for
laboratory black-body
radia-
tion because such radiation has
not
yet
reached
thermal
equilibrium
(see
Jeans
1905c, p. 293).
Rayleigh
had stated
in
1900 that "although
for
some
reason
not
yet explained
the doctrine
[of
equipartition]
fails in
general,
it
seems
possible
that it
may
apply to
the
graver
modes
[long
wavelengths]" (Rayleigh 1900, p. 540).
For
a
discussion
of
attempts
to account
for the failure
to obtain
Planck's
law from the
equipartition
theorem, see
Garber
1976.
[71]
Lorentz stated this
hope
in Lorentz
1908a,
p.
19,
and Lorentz
1908b,
p.
562.
[72]
See Lummer
and
Pringsheim
1908.
[73]
See
Jeans
1908.
[74]
See Ritz 1908b.
[75]
Lorentz
1908b, p.
562. See also Hendrik