178 DOC.
38 ETHER AND RELATIVITY
20
SIDELIGHTS
ON
RELATIVITY
former,
disregarding
the
causes
which
con-
dition
its
state.
Thus
we
may
also
say,
I
think,
that the ether
of
the
general
theory
of
relativity
is
the
outcome
of
the
Lorent-
zian ether,
through
relativation.
As
to
the
part
which the
new
ether
is
to
play
in
the
physics
of
the future
we are
not
yet
clear.
We know
that it
determines
the
metrical relations in
the
space-time
[24]
continuum,
e.g.
the
configurative possi-
bilities
of
solid bodies
as
well
as
the
gravita-
tional
fields;
but
we
do
not
know whether
it
has
an
essential share in
the
structure of
[25]
the
electrical
elementary
particles
consti-
tuting
matter. Nor do
we
know whether
it is
only
in
the
proximity
of
ponderable
masses
that its
structure differs
essentially
from
that
of
the Lorentzian
ether;
whether
[26]
the
geometry
of
spaces
of
cosmic extent
is
approximately
Euclidean.
But
we can
assert
by
reason
of
the relativistic
equations
of
gravitation
that there
must be
a
depart-
ure
from Euclidean
relations,
with
spaces
of
cosmic order
of
magnitude,
if
there
exists
a positive mean density, no
matter
[27]
how
small, of
the
matter in
the
universe.