FOUNDATIONS

OF

STATISTICAL

PHYSICS 43

Just

as

he studied

Maxwell's

electrodynamics on

his

own,

Einstein

pursued

his

interest

in

thermodynamics

and kinetic

theory

through

independent

reading.

Among

the first books

that he studied

was

Mach's

Wärmelehre,

which he

probably

read

in

1897

or shortly

there-

after.[18]

But

as

Einstein's

papers

on

statistical

physics

themselves make

clear,

Boltz-

mann's Gastheorie

was

the most immediate influence

on

his work in this

field.[19]

He

began an

intensive

study

of

Boltzmann,

perhaps

in the

summer

of

1899,[20]

and late the

following summer

he wrote:

I

am firmly

convinced

of

the correctness

of

the

principles

of

the

theory, that

is,

I

am

convinced that

in

the

case

of

gases

it is

really a

matter

of

the movement

of

discrete

mass

points

of

definite,

finite

magnitude

that

move

in accordance

with

certain

conditions.

. . .

It

is

a

step

forward in the

dynamical explanation

of

physical phenomena.

Ich bin

fest

von

der

Richtigkeit

der

Prinzipien

der

Theorie

überzeugt,

das

heißt

ich

bin

überzeugt,

daß

es

sich

wirklich

um

Bewegung

diskreter

Massen-

punkte

von

bestimmter endlicher Größe bei den Gasen

handelt,

die sich

gemäß

gewissen Bedingungen bewegen.

. . .

Es ist ein Schritt weiter in

der

dyna-

mischen

Erklärung

der

physikalischen Erscheinungen.[21]

Einstein continued to

study

the

Gastheorie

at least

through

the

summer

of

1901

.[22]

In the

spring

of

that

year,

he mentioned O. E.

Meyer's

widely

read text, Die kinetische Theorie

der

Gase,

as a possible source

of

empirical

data for

an investigation

of intermolecular

forces that he

was

then

carrying

out with

Maric's

assistance,[23]

and also asked Maric to

send him

a copy

of Kirchhoff's

Vorlesungen

über

die Theorie

der

Wärme.[24]

He

seems

to

[18]

See Mach 1896. Besso recalled

recom-

mending

Mach's

writings to

Einstein in 1897

or

1898

(Michele

Besso

to Einstein, 12

October-8

December

1947);

Einstein recalled that Besso

had

recommended

both the

Mechanik

(Mach

1897)

and the Wärmelehre

"during

my

first

years

of

[university]

studies"

("während meiner

ersten Studienjahre") (Einstein to Besso, 6

Jan-

uary

1948),

and

"about

the

year

1897"

("etwa

im Jahre 1897")

(Einstein to

Carl

Seelig, 8

April

1952).

A

copy

of

the second edition

of

the

Wärmelehre,

Mach

1900b, is

in

Einstein's

per-

sonal

library

and contains

a

few short

marginalia

in

Einstein's

hand. The earliest

extant

mention

of

Mach in

Einstein's

correspondence

is

in Ein-

stein to Mileva

Maric, 10

September

1899

(Vol.

1,

Doc.

54).

[19]

See Boltzmann

1896, 1898a.

A

copy,

with

the label

of

a

Milan book

store, is

in

Einstein's

personal library

and contains

a

few,

mostly

in-

significant marginalia

and inclusions in Ein-

stein's

hand.

[20]

See Einstein

to

Mileva Maric,

10

Septem-

ber 1899

(Vol.

1,

Doc.

54).

[21]

Einstein to Mileva

Maric, 13

September

1900

(Vol.

1,

Doc.

75).

Shortly

thereafter,

Ein-

stein sent Boltzmann

a manuscript copy

of

Ein-

stein 1901

(Doc.

1)

(see

Mileva Maric to Helene

Savic, 20 December

1900,

Vol.

1,

Doc.

85);

for

a

discussion

of

the

possible

influence

of

Boltz-

mann

1898a

on

this

paper, see

the editorial

note,

"Einstein

on

the Nature

of

Molecular

Forces,"

p.

4. Einstein's

sister

Maja

claimed

that Einstein

continued

to

correspond

with Boltzmann until

the

latter's

death;

but she stated that their

corre-

spondence

concerned the

theory

of

relativity

(Winteler-Einstein

1924, p. 18).

[22]

See

Einstein to Marcel

Grossmann,

6

Sep-

tember

1901

(Vol. 1,

Doc.

122).

[23] Meyer,

O. E.

1877, 1895, 1899

(see

Ein-

stein

to

Mileva

Maric,

30

April 1901,

Vol.

1,

Doc.

102).

For

a

discussion

of

Einstein's

work

on

molecular

forces,

see

the editorial

note,

"Einstein

on

the Nature

of

Molecular Forces,"

pp.

3-8.

[24]

See Kirchhoff

1894.

For the

request,

see

Einstein

to

Mileva

Maric, 15

April

1901 (Vol.

1,

Doc.

101).