DOC.

1

MANUSCRIPT ON SPECIAL RELATIVITY

3

Doc.

1

Manuscript

On the

Special

Theory

of

Relativity

[1912-1914][1]

[p.

1]

Section

One.

An

Outline

of

Lorentz's Electrodynamics

§1.

The

Fundamental Maxwell-Lorentz

Equations for

the Vacuum in

the Absence

of

Electrically

and

Magnetically

Polarizable

Bodies

A

complete

understanding

of

the

justification

of the

theory

that

we

today

designate

as

the

theory

of

relativity

is

possible only

if

we

call

to

mind the outlines of the

development

of

electrodynamics

since Maxwell. We will therefore

briefly

review the

basic ideas of this

development.

Quantity

of

electricity.

If

electrically charged corpuscles

are

(continually) present,

then,

as we

know,

their electrical

charges

e1 e2

...

can

be defined

as

follows:

Let the

ratio

e1:e1

etc.

be

equal

to

the ratio of the forces

experienced by

the

corpuscles

in the

same

electrostatic

field.[2]

This definition is

possible

because the above ratio is known

from

experience

to

be

independent

of the choice

of

the field.

Further,

one can

determine the absolute

magnitude

of the

charges

e

by postulating

that the

repulsive

force exerted

by

two

corpuscles (say,

those with indices

1

and

2) on

each other

in

vacuum

is

equal

to

e1e2/4nr2.

This

expression

contains,

on

the

one

hand,

Coulomb's

empirical

law

and,

on

the other

hand,

the definition of the electrostatic unit

as

introduced

by

Heaviside[3]

and

H. A.

Lorentz.

Thus,

e/V4n

is

the

quantity

of

electricity

measured in the

customary

electrostatic units.

Electrical

field

strength.

By

the electrical field

strength[4]

e

in

vacuum one

understands the

vector

that-when

multiplied

by

e-is

equal

to

the

vector

of

the

force

that the field

exerts

on a

stationary corpuscle

endowed with

charge

e.

The

magnetic pole strength p

and the

magnetic

field

strength

in

vacuum

h

shall

be defined in

an analogous way.

The first

system

of

Maxwell's

equations

in the

absence

of

electrically

and

magnetically polarizable

media.

A

temporally

constant,

closed electrical circuit

produces

a magnetic

field that

is

determined

by

the

following

rule: The line

integral

of the

magnetic

field

strength over

an

arbitrary

closed

curve

(line

element

d§) is

equal

to

the

surface

integral

of the vector i of the electrical

current

density

divided

by

a

certain

constant

c.

The

components

of this

vector

are thereby

defined

as

those