DOC. 24 RESPONSE TO
QUESTION
BY REIßNER
281
everywhere
at
infinity,
the
guv
assume
the
values
-1
0
0 0
0-1
0 0
0
0-1 0
0 0 0
c2
where
c
is
a
constant. Furthermore,
we
chose the reference
system
in such
a
way
that
both the
system
E
as a
whole,
as
well
as
the material
point equivalent
to
it,
will be
at rest
relative
to
the reference
system,
i.e.,
that
I1,
I2,
I3,
as
well
as
I1*, I2*, I3*
vanish. Then
we
get
I4 =
/($44
+
t44)dV
I*4
=
mc.
These
two
quantites
are
to
be
set
equal
to
each
other,
where
I4
has the
meaning
of
the "rest
energy"
U0.
Hence,
m
=
U0/c.
Thus,
the inertia of
a
closed
system
E
is
completely
determined
by
its
rest
energy.
It has been shown here that the
energetic components
of the
gravitational
field
contribute
to
the
gravity
and inertia of
a
system
in
exactly
the
same
way
as
do the
energetic components
of material
structures.
(Received
on 11
December
1913)