DOC.
37
AUTHOR'S SUMMARY
219
Doc.
37
Author's
Summary
of
The
Foundation
of
the
General
Theory
of
Relativity
Not translated for this volume.
218
DOC. 36 REVIEW OF LORENTZ
Doc. 36
Review
of H. A.
Lorentz,
Statistical
Theories
in
Thermodynamics:
Five Lectures
...
[p. 375]
[1]
Whoever has
studied mathematical theories has had the
following, embarrassing
experience:
he verifies
every step
in
a
deduction with
diligence
and
eagerness,
and
at the
end
of his efforts he understands
nothing.
He did not
get
the
guiding
idea of
the whole
concept
because the author
himself
suppressed it,
either from
an
incapacity
to
phrase
it
concisely, or worse,
from
an
almost comical
coquettishness-as
the
insightful
would say-which
was especially popular
in the
past.
This evil
can only
be
overcome by
unrestrained
openness
of the
author,
who should not
shy away
from
familiarizing
the reader
even
with his
incomplete guiding
ideas
if
they
have furthered
[p. 376]
his
own
work. There is
hardly
a
field in theoretical
physics
where this commandment
is
more
difficult to fulfill than
in
statistical mechanics.
Every knowledgeable
reader
[2]
will
agree
with
me
that
Gibbs,
in his
pioneering
book about this
very topic,
has
sinned
quite a
lot
against
this commandment.
Many
have read
it,
many
have verified
it-and
did not understand
it.
Lorentz tackled this evil in his first three lectures
by
displaying
the foundations
of
the
theory
in
a
stunningly simple
mathematical
form,
such that the
guiding
ideas
are
sharply
focused
upon.
In
doing
so,
he
puts
Boltzmann's
principle
at
the
forefront,
and
thoroughly
discusses the
question
of
how the
probability
W in
Boltzmann's
equation
S
=
Klg
W
is to be defined.
Thereby
he
uses
the definition "W
=
phase integral"
and demon-
strates that the definition which has been
suggested by
this
referee,
"W
=
frequency
of
occurrence as a
function
of
time,"
is
essentially
the
same.
The author
explains
on
this occasion what made him refrain from the
second, more descriptive definition;
and
[3]
I
specifically
want to direct the reader's attention
to
this
point.
The last
two
lectures deal
mainly
with the
theory
of Brownian
movement and
with fluctuations. The
last lecture is
a masterly application
of
this latter
theory
to
Planck's radiation
formula. As is well
known,
there
emerge
statistical
properties
of
radiation that cannot be
represented by
the undulation
theory.
The fact that these
relations found
H.
A. Lorentz's interest is
a special pleasure
to this reviewer.
Every
physicist can
learn from this
illuminating
booklet.
A.
Einstein,
Berlin-Charlottenburg