EINSTEIN'S
LECTURE NOTES
7
cut
choice between
1910
and
1912 cannot be
made
on
the basis of the available
material,
the notebook
is assigned
the earlier
date,
that
is,
the
summer
semester
of
1910.[24]
It
seems
that
Einstein found lectures
on
the
theory
of
heat to be
the
most
interesting
ones
to
prepare. A
course on
the molecular
theory
of heat
given
in 1908
was
his first
course
and
was
subsequently repeated
three
times.
His interest
in
kinetic
theory
and
statistical
physics
reveals
itself also
in the
character
of his
notes,
which
clearly
show
the
course
to be
the
most
original
of
his
lecture
courses.
The material
presented
in
the
notebook
can
be divided into
two
parts.
The
first
part
gives a simplified
but
compre-
hensive
account
of
the
kinetic
theory
of
gases.[25]
Einstein
here
follows
Boltzmann's
Vorlesungen
über Gastheorie
(Boltzmann 1896, 1898),
which
at
the time
was a
standard
reference
on
this
topic
and which Einstein had studied
during
his
student
years.[26]
He
also includes detailed discussions of
contemporary
and
ongoing research,
such
as
the
investigations by
Knudsen mentioned above. Einstein then
leaves
the
general
theme
of the kinetic
theory
of
gases
and
starts
an
altogether
new
section
under the
title
"Molecular Processes and
Probability" ("Molekulare Vorgänge
und Wahrscheinlich-
keit").
Similar
to
the
approach adopted
in
the mechanics
notebooks,
this section
starts
with
an
elaborate and careful discussion of
the
fundamental
concepts-in this
case,
of
the
concept
of
probability
and the
principles
of statistical mechanics. Einstein's
treat-
ment
is
based
on
his
early
work
on
statistical
physics,
but
also
clearly
shows
that
by
this time he had read Gibbs's book
on
statistical mechanics.
After
having
laid
the
foundations, he turns to
applications
and
more specific
issues
such
as
the
problem
of
specific
heats,
Brownian
motion,
and also
to
Langevin's
and
Weiss's
theories of
paramagnetism
and
ferromagnetism.
After
his
move
to
Berlin
in 1914
Einstein continued
to
give
lectures
on
statistical
mechanics.[27]
Student
notes
of
courses given
in
1917-1918 and
1918,
respectively,[28]
show
that
Einstein used
his notes
on
kinetic
theory
of heat for these lectures
as
well.
[24]This
particular course
was
taken
by
fourteen students and
eight
auditors
(Kontrollbücher
über die
Honorargebühren, S.S.
1910,
SzZU, Kassa-Archiv).
[25]A
similar, though less
technical
exposition
of much of the material
in
the
first
part
of the
notebook is
given
in
Einstein
1915a.
For Einstein's
general views
on
kinetic
theory, see
also
his
obituaries of Smoluchowski
(Einstein 1917)
and
Warburg
(Einstein 1922).
[26]See,
e.g.,
Einstein
to
Mileva
Maric, 13 September
1900
(Vol.
1,
Doc.
75),
for Einstein's
earlier
use
of Boltzmann's lectures and
his
enthusiasm about them. Both volumes
are
in
Einstein's
personal library.
Evidence for Einstein's
use
of Boltzmann
in
preparing
his
lectures
is
found
in
two
letters
to
Conrad Habicht
in
which
he
asks Habicht
to
bring
him "the Boltzmann"
because
he
needs it
for
his
lectures
(Einstein
to
Conrad
Habicht,
14
December
1909
and
4
March
1910).
He
is
also
likely
to
have consulted such textbooks
as Meyer, O.
E.
1899, a
copy
of which he had ordered
in 1908
(see
Einstein
to
Mileva
Einstein-Maric, 17 April
1908),
Kirchhoff 1894,
and
Clausius
1879-1891. For
a
further discussion of Einstein's
acquaintance
with relevant
sources,
see
Vol.
2,
the editorial
note,
"Einstein
on
the Foundations of Statistical
Physics," pp.
41-55.
[27]See Appendix B,
"Einstein's Academic
Courses," pp.
598-600.
[28]Notes
by
Walter Zabel and Werner
Bloch
of the
1917/18 course
have been
preserved,
as
have
notes by
Hans Reichenbach of
the 1918
course.