356 DOC.
42 SPECIAL AND GENERAL RELATIVITY
TWENTY-NINE
The
Solution
of
the
Problem
of
Gravitation
on
the
Basis
of the
General
Principle
of
Relativity
If
the reader
has
followed
all
our
previous considerations,
he
will
have
no
further
difficulty
in
understanding
the
methods
leading to
the
solution of the
problem
of
gravi-
tation.
We
start
off
from
a
consideration
of
a
Galileian
domain,
i.e.
a
domain in which there
is
no
gravitational
field relative
to
the
Galileian
reference-body K.
The
behaviour of
measuring-rods
and clocks with reference
to
K is
known
from the
special
theory
of
relativity,
likewise the behaviour
of "isolated"
ma-
terial
points;
the latter
move
uniformly
and in
straight
lines.
Now let
us
refer this domain
to
a
random Gauss co-ordinate
system
or
to
a
"mollusc"
as
reference-body
K'.
Then
with
respect to
K' there
is
a
gravitational
field
G
(of
a
particular
kind).
We learn
the
behaviour of
measuring-rods
and clocks
and
also
of
freely-moving
material
points
with reference
to
K'
simply by
mathematical transformation. We
interpret
this be-
haviour
as
the
behaviour
of
measuring-rods,
clocks and
mate-
rial
points
under
the influence
of
the
gravitational
field
G.
Hereupon we
introduce
a hypothesis:
that
the influence
of
the
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