DOC.
17
JULY
1914 29
17. From Walther Nernst
Berlin,
26a Am
Karlsbad, 2 July 1914
Dear
Colleague,
According
to
Clausius-Clapeyron
for the steam
pressure,[1]
lnp
=
+
2.5lnT4 Io^iT
+ C' *
=
W+5/£T
applies.
U
=
energy
content
of
the
rigid body,
C
the
“chemical constant” accord-
ing
to
my
heat
principle,
only dependent
on
the
nature of
the
gas, according
to
Sackur[2]
C/2.3026
=
1.45
+
1.5
logM.
We set
according
to
Stern[3] U
=
3R
Bv/Bv/T-1;
thus
resulting
in
fr=-3ñm(^-i)
+
^.
Otherwise,
lnp
=
+
2.5
lnT
+
3
ln
(er
-
l)
-
3^
+
C.
or
(T
large!)
lnp
=
-iA°-+
^^
-
0.5
ln T
+ 3
ln
ßv
+
C
Stern
commits
the
error
of confusing
C
with
3
ln
ßv
+
C;[4]
his kinetic
result
(following
the
completely
unnatural
model)
is
simply
nonsensical
when
you proceed
from Sackur
or
from
my
theorem.[5]
When in
the
thermodynamic
derivation Stern talks of
“zero point
energy,”
that
is
a
second
very gross blunder;[6]
the above
simple
derivation shows that,
as
is
obvious from
the
outset,
of
course,
such
hypotheses
are
not
used in
thermody-
namic
derivations.
“This
was
the
first trick
And
the
second
follows
forthwith.”[7]
Namely,
the
diagram
Best
regards, yours,
W.
Nernst
N.B.
It
is not
worth
considering
further the
confusion, corresponding
to
the
above,
reigning
in Stern’s
L0
and
A0
=
model.[8]