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