236
DOCS. 325-327
DECEMBER
1911
important
for
the
theory
of
specific
heats.
We will
talk about
this
and
many
other
things
when
we are
together
again.
(I
no
longer
doubt
it!)
Happy
holidays
to
you
and
your family
(our
university
is already "celebrating")
from
your
Einstein
My
wife
sends her best
regards
326.
From Robert Gnehm
[Zurich]
16
December
1911
Please
come
if
possible.[1]
Gnehm
327. To Willem Julius
Prague,
18
December
1911
Dear
Colleague:
It
is not
without
some
dread that
I
fulfill the
obligation
with which
you
saddled
me.
It
is hard,
I
would almost
say
presumptuous (of me), to compare
such fine scientific
workers
with
one
another
as
regards
their
importance.[1] Only
the fact
that
such
a
comparison is necessary at
this
moment
gives
me
the
courage
to
take
part
in it. I
studied
the authors
in
question
as thorougly
as
possible
and will
now
summarize
my impressions.
Ornstein
is certainly
an
astute theoretician,
but
his
achievements
do not
bear
comparison
with
those
of
van
Laar,
Keesom,
and
Debye.[2]
Van Laar
has
an
excellent
command of
the Gibbs-Planck
thermodynamic
theories
and
is
unquestionably
rich in ideas. But
the
physical
results of
all his
many
mental
efforts
are
really
rather
meager.
In
my
opinion,
he lacks
an eye
for
the
immediately real;
he
sees exclusively
through
the
lenses
of
classical
thermodynamics.
And the
manner
in
which he
develops
his
arguments
is not
always
unobjectionable.
Let
me
give an example
from
one
of
the
relatively
few
papers
of
his
that
I checked
carefully.
In
his
paper,
"Uber
die
genauen
Formeln
für
den
osmot.
Druck
..."
(Zeitsch.
für
phys.
Chemie
15,
p.
464,[3]
he derives the
following
equation
for
the
osmotic
pressure
ir
TT =
~(f
-
logC1
(1)
R
gas
const.
r
abs.
temperature