DOC.
38
221
per
gram-equivalent. Thus,
summation
over
all
species
of oscillating
elementary structures occurring
in
the solid substance
in
question yields the
following
expression
for the
specific
heat
per
gram-equivalent1:
ßv
(8a)
c
=
5.94
J
T
I1
2
e
T
-
1
The
above
figure2 shows
the value
of expression
(8)
as a
function of
x
=
(T/ßv).
If
(T/ßv)
0.9,
the contribution
of
the
structure to
the
specific
molecular heat
does not
differ significantly
from
the value
5.94, which
also
follows from the heretofore
accepted
molecular-kinetic
theory;
the smaller the
v,
the
lower
the
temperature
at
which
this will
already
be
the
case.
In
con-
trast,
if
(T/ßv)
0.1,
the
elementary
structure
in
question does not
contri-
bute significantly to
the
specific
heat. In
between,
the
expression
(8)
initially
grows
faster
and then
more
slowly.
From what
has been
said it follows first
of
all that the electrons
capable
of
oscillation,
which have
to
be postulated to
explain
the ultraviolet
proper
frequencies,
cannot
significantly contribute
to
the
specific heat
at
normal temperatures
(T
=
300),
because
the inequality
(T/ßv)
0.1 becomes
[23]
the
inequality
A
4.8 u
at
T
=
300.
On
the other
hand,
if the
elementary
structure
satisfies the condition
A
48u,
then
according to
what
has been
said
above,
its contribution
to
the
specific heat
must
be
close
to
5.94
at
usual
temperatures.
Since
generally
for
infrared
proper
frequencies
A
4.8u, according
to
[24]
our
conceptions
these
proper
oscillations
must
contribute
to
the
specific
heat,
and
the
greater
the
A,
the
greater
this contribution.
According
to
Drude's
investigations,
these
proper
frequencies
are
to be
attributed
to
the
[25]
ponderable atoms
(atom
ions)
themselves.
The most
obvious conclusion
seems
therefore
to
be to
consider
exclusively
the
positive
atom
ions
as
the carriers
of
heat
in solids
(insulators).
1This
consideration
can
easily
be
extended
to anisotropic bodies.
2Cf.
dashed
curve.