DOC.

5

LOCALIZATION

OF ELECTROMAGNETIC ENERGY

253

Published in

Archives des sciences

physiques

et

naturelles

29

(1910):

525-528. Lecture delivered

to

the Societe

Suisse

de

Physique,

Neuchätel, 7 May

1910. Published

15

May

1910.

[1]In

these

equations, p

is

(

- J

pv,

where

pv

is

the radiation

energy

density per

unit

frequency

at

v,

and

c

is

the

speed

of

light.

The

exponent

of

e

is

-hv/kT

in

the

first equation

and

hv/kT

in

the

second

equation,

where k

is

Boltzmann's

constant.

[2]For Einstein's earlier

analysis

of

these

phenomena, see

Einstein

1905i

(Vol. 2,

Doc.

14).

[3]Einstein characterizes

light

by

its

dispersion

in

a

medium rather than

by

its

frequency so

that

his

formulation

becomes

a

statement

exclusively

about

experimental

facts.

The

subsequent

discussion is

largely

based

upon

Einstein's earlier

work;

for

comments

on

this earlier work and

for references

to

secondary

literature,

see

Vol.

2,

the editorial

note,

"Einstein's

Early

Work

on

the

Quantum Hypothesis,"

pp.

134-148.

[4]For the contributions of Jeans and Lorentz

to

the derivation of the

Rayleigh-Jeans

for-

mula,

see

Jeans

1905,

Lorentz

1903,

1908.

For Einstein's earlier derivation of the

same law, see

Einstein

1905i

(Vol. 2,

Doc.

14).

For

his comments

on

the influential derivation

in

Lorentz

1908,

see

Einstein

to H. A.

Lorentz, 13 April

1909.

[5]Einstein

had earlier formulated

his

position

that

the

understanding

of radiation

requires

the combination of two

structures in

Einstein

1909c

(Vol.

2,

Doc.

60), p.

499. His view

was

not

commonly accepted

at

that

time; see,

e.g.,

Max Planck

to Einstein, 6

July 1907,

H. A.

Lorentz

to Einstein,

6 May 1909, as

well

as

Einstein

et al. 1914

(Doc.

27),

and the discussion of

Einstein

1914

(Doc.

26),

Einstein's

report

to

the

Solvay

Congress.

[6]Einstein

1905i

(Vol. 2,

Doc.

14).

[7]Einstein had earlier mentioned this

argument

in

Einstein

to H. A. Lorentz, 23

May

1909.

He

explained

it

in

a

discussion remark

following

his

report

to

the

Solvay

Congress;

see

Einstein

et

al. 1914

(Doc.

27), pp.

358-359.

[8]Einstein had earlier referred

to

the

example

of action-at-a-distance theories

in

Einstein

1909c

(Vol. 2,

Doc.

60), p.

499. See

also Einstein's

response

to

Planck

(Doc.

3),

note

8.