EINSTEIN ON BROWNIAN
MOTION
I
Einstein's
study
of
Brownian motion constitutes
one
of
the
high points
in
the
long
tradition
of
research
on
the kinetic
theory
of
heat and
of
his
own
contributions to this
field.[1]
Some
of
the
consequences
of
his
work
were
of
great
significance
for
the
development
of
physics
in the twentieth
century.
Einstein's
derivation
of
the laws
governing
Brownian
motion,
and
their
subsequent experimental
verification
by
Perrin and others,
contributed
signifi-
cantly
to the
acknowledgment
of
the
physical reality
of
atoms
by
the
then
still
numerous
skeptics.
His
papers on
Brownian motion
helped
to establish the
study
of
fluctuation
phe-
nomena as a new
branch
of
physics.
The methods he created in the
course
of
his
research
prepared
the
way
for statistical
thermodynamics,
later
developed
by
Szilard and
others,
and
for
a general theory
of
stochastic
processes.
Einstein
published
four
major
articles
on
Brownian motion in
liquids
between
1905
and 1908: Einstein 1905k
(Doc. 16),
Einstein 1906b
(Doc. 32),
Einstein
1907c
(Doc. 40),
and
Einstein
1908c
(Doc. 50).
His
own summary
of
a
lecture to the
Naturforschende
Gesellschaft
Bern,
Einstein
1907f,
is
presented
as
Doc. 43. He also
published
three
papers
on
related
topics during
this
period:
the
first, originally
published
as
Einstein's
disserta-
tion,
Einstein
1905j (Doc. 15),
deals with
the determination
of
molecular
dimensions;[2]
the two others
concern
Brownian motion in condensers and its measurement,
Einstein
1907b
(Doc. 39),
and Einstein
1908a
(Doc. 48).
Finally,
a
remark
by
Einstein
on
the
measurement
of
Brownian motion made after
a
talk
that
was
given
at the 1909
Salzburg
meeting
of
the Gesellschaft Deutscher Naturforscher und Arzte
is reproduced, together
with
other
discussion
contributions,
as
Einstein
et
al.
1909a
(Doc. 58).
In
1920, Wolfgang Ostwald,
editor
of
Ostwald's Klassiker der
exakten
Wissenschaften,
proposed
to
Einstein
an
edition
of
his
papers on
Brownian motion and diffusion.[3]
The
resulting
volume,
Einstein
1922,
reprints
most
of
these
papers.[4]
An
English
translation
appeared as
Einstein 1926.
[1]
For studies
of Einstein's
work
on
Brownian
motion,
see,
e.g.,
Brush
1968,
and
Pais
1982,
chap.
2,
§
5.
[2]
For
a
discussion
of
this
paper, see
the edi-
torial note,
"Einstein's
Dissertation
on
the
De-
termination
of
Molecular Dimensions,"
pp.
170-182.
[3]
Wolfgang
Ostwald to
Einstein,
22
Novem-
ber
1920. Einstein
immediately agreed, leaving
to
Ostwald the decision about which
of
his arti-
cles should be
reprinted
(Einstein
to
Wolfgang
Ostwald,
22
November-20
December
1920).
In
his
reply,
Ostwald
informed Einstein that he in-
tended
to
appoint
Reinhold Fürth
as
co-editor
(Wolfgang
Ostwald
to
Einstein, 20 December
1920).
See
Fürth
1980,
for evidence that Fürth
wrote Einstein,
asking
for his consent to the
preparation
of
the edition.
[4]
The
reprinted papers are
Einstein 1905k
(Doc. 16);
Einstein 1906b
(Doc. 32);
Einstein
1906a,
incorporating
the correction
of
a
calcu-
lational
error
and 1906c
(Doc. 33);
Einstein
1907c
(Doc. 40);
and Einstein
1908c
(Doc. 50).
Some
of Fürth's
annotations
for the 1922 edition
(Fürth
1922)
have been utilized in these editorial
notes.