DOC.

7

RELATIVITY

LECTURE NOTES

67

[1]This

document

is

dated

on

the

assumption

that

Einstein

prepared

these

notes

for

his

course

in

winter

semester

1914/1915

at

the

University

of

Berlin,

16

October 1914-15 March

1915 (see

Berlin

Verzeichnis

1914,

title

page).

[2]The

exposition

of

special

relativity

and

covariant

electrodynamics

in

these lecture

notes

shows

many

similarities with the

treatment

in

an

unpublished manuscript

on

special relativity

from

1912 to 1914 (see Vol.

4,

Doc.

1).

In

the

following,

this

manuscript

will

simply

be

re-

ferred

to

as

"Vol.

4,

Doc. 1."

These lecture

notes

also

follow rather

closely

the section

on

spe-

cial

relativity

and

covariant

electrodynamics

of the

course on

electricity

and

magnetism

that

Einstein

gave

at

the

ETH in

winter

semester

1913/1914

(see

the lecture

notes by

Eduard

Sidler

in

SzZE

Bibliothek, Hs. 1067:15,

and their

summary in Vol.

4, Appendix A;

see

also Einstein's

notes

for

part

of this

course

in Vol.

4,

Doc.

19).

[3]The

idea of

geometry

as

part

of

physical

science is also

expounded

in Vol.

4,

Doc.

1,

[pp.

21-22],

and

in

the first section of Einstein's

popular

book

on

relativity

from

1917,

Einstein

1917a

(Doc. 42).

[4]See, e.g.,

Laue

1913, §2,

or

Vol.

4,

Doc.

1, [pp.

15, 20],

for discussions of Fizeau's

ex-

periment.

[5]See, e.g.,

Lorentz

1909, §§156-164,

for Lorentz's derivation of the

dragging

coefficient.

[6]See,

e.g.,

Laue

1913,

§2,

for

a

discussion of aberration. Stellar aberration

is

also

a

topic

in

Einstein's

first

paper

on

special relativity,

Einstein 1905r

(Vol. 2,

Doc.

23).

[7]See

Vol.

4,

Doc.

1,

Section

One,

for

a more

detailed

exposition

of Lorentz's

electrody-

namics.

[8]In

the

following

calculation of the determinant

above,

second-order

quantities

are ne-

glected.

The

speed

of

propagation

of

light

in

the

running water V

is

written

as

V

=

V0

+ A,

where

A

is

a

small

quantity. Subscripts

x are

suppressed.

See

also Einstein's calculation

in Vol.

4,

Doc.

1, [p.

15].

[9]"V"

should

be

"V0."

[10]"e2"

should be

"Je."

[11]See,

e.g.,

Laue

1913,

§2,

Pauli

1921,

sec.

36,

and

Vol.

4,

Doc.

1, [p. 7],

for discussions

of the

experiments

of

Röntgen,

Eichenwald,

and Wilson. The

experiments

by

Röntgen

and

Eichenwald showed that

a

dielectric

moving

in

an

electric

field

produces

a

magnetic

field

due

to

the motion of induced surface

charges (see Röntgen 1888

and

Eichenwald

1903, 1904); in

Wilson's

experiment

the motion of

a

dielectric

in

a

magnetic

field

was

shown

to

induce

a po-

larization

in

the dielectric

(see

Wilson

1904).

[12]See

Lorentz

1895.

[13]Without the

Lorentz-Fitzgerald

contraction

hypothesis,

Lorentz's

theory

of

1895

could

not account

for the

negative outcome

of the

Michelson-Morley experiment

nor

of other

sec-

ond-order

experiments to

determine the motion of the earth

through

the ether.

[14]A

factor -1/2

is

missing

in

the last

term.

[15]Einstein

had

on

earlier occasions characterized the Lorentz-FitzGerald contraction

as an

ad

hoc

hypothesis

(see,

e.g.,

Einstein

1915b

[Vol. 4,

Doc.

21],

p.

707;

see

also Lorentz's de-

fense in H.

A.

Lorentz

to

Einstein,

between

1

and

23

January 1915).

[16]See Ritz

1908a,

1908b for Walter Ritz's emission

theory

of

light.

Einstein

discusses

its

consequences

in Vol.

4,

Doc.

1, [pp.

21

and

20a].

[17]The

Dutch

astronomer

Willem

de

Sitter had shown that

an

emission

theory

of

light

was

incompatible

with observational data

on

the

motion of double

stars.

See De

Sitter

1913a,

1913b;

see

also Einstein's discussion

in Vol.

4,

Doc.

1, [p.

20a],

and

his

praise

of

De

Sitter's

work

in

Einstein

to

Paul

Ehrenfest, 28

May

1913

(Vol. 5,

Doc.

441).

[18]Possibly a

reference

to

work

by

Edouard

Guillaume,

in

which

it

was

shown that

a

speed

of

light exclusively

dependent on

the

speed

of

the

source

could

give

rise

to

local accumulations

of

energy uncompensated

by any

work.

In

a

comment

on

Guillaume's

presentation

of this

re-

sult

at

a

meeting

of

the

Societe suisse

de

physique

in

Basel

(see

Guillaume

1914),

Einstein had

pointed out

that

through

the

same

mechanism

one

could

give

a

body

a

higher temperature

than

its

surroundings,

without

any

compensation

elsewhere.