DOC.
23
MAX
PLANCK AS SCIENTIST
271
Doc.
23
Max Planck
as
Scientist
by
A.
Einstein
[Naturwissenschaften
1
(1913):
1077-79]
For the
academic
year
1913-14, the
rectorship
of the
University
of
Berlin has been
bestowed
upon
the theoretical
physicist
Max Planck.
We,
his close and his distant
[2]
colleagues,
wish
joyfully
to
take this
opportunity
to
celebrate with
gratitude
the
achievements that
science
owes
to
his creative
activity.
Max Planck's first
independent
work
was
his
inaugural
dissertation,
"Über den
zweiten
Hauptsatz
der mechanischen Wärmetheorie"
["About
the Second Law
of
the
Mechanical
Theory
of
Heat]"
which he
presented
at
the
age
of
21 to
the
University [3]
of Munich in
1879.
It
is characteristic
that
Planck
started his
publishing
activity
with
the
treatment
of
a
topic
of
such
generality, only
to
turn,
in
subsequent years,
to
the
treatment
of
more specific problems
that
were
naturally
connected with those first
investigations.
This is characteristic of his
way
of
working,
perhaps
of the method of
the
pure
theoretician in
general.
He
always
starts out
from
a
proposition
of
the
greatest possible generality
and deduces
from
it individual
special results,
which he
then
compares
with
experience.
Planck's first
great
scientific
accomplishment
is
the third
of
his
papers,
entitled
"Uber das
Prinzip
von
der
Vermehrung
der
Entropie"
["About
the
Principle
of
Entropy
Increase"]
(Wied.
Ann. 32
(1887): 462),
which deals with the
general theory
[4]
of chemical
equilibrium,
with
special
attention
given
to
dilute solutions. To be
sure,
the
general
results of this
paper
had
already
been derived
more
than
10
years
earlier
by
Gibbs,
and those
concerning
dilute solutions
partly by
van't Hoff. But Gibbs's
[5]
papers
were
little
known and
not
easily
accessible;
even
just
to
recognize
their value
[6]
was
already
an
accomplishment, and,
in
fact,
I
believe that Planck would have
passed
over
Gibbs's
papers uncomprehendingly,
like almost
everyone else,
had he
not
independently
embarked
upon
a
similar road. The
great
value
of
Planck's aforemen-
tioned work lies in the fact that
he established
a
few formulas
regarding
the
equilibrium
of dilute solutions of
a generality so great
that all of the
thermodynami-
cally
derivable laws
on
dilute solutions
are
contained
in
them.
On
the basis
of
his
general formulas,
Planck
was
the
first,
and thus ahead of
Arrhenius, to
conclude that
[8]
in
aqueous
solutions with
"abnormally high" vapor pressure
reduction
(resp.
lowered
freezing point
or
raised
boiling point)
the dissolved substance
must
be dissociated.
Planck's
general
formulas include the so-called Ostwald law of dilution for
binary
electrolytes as a completely special
case.
[9]
[7]
We
are
not
going
to
speak
here about Planck's
papers
that
deal with
more
[1]