SUMMARIES OF
ETH
COURSES 629
Laplacian is
known, and
that
the field
equations
can
be
derived
from the
knowledge
of
this term and the form
of
the
energy-momentum
conservation
law. He
quoted
the
field
equations
and
noted that
the
equivalence
of
inertial and
gravitational
mass
follows
from them
and the
conservation
laws. He also
pointed
out
that
the
equations
are only
covariant
with
respect
to
general
linear transformations
but
that
they
are
not
generally
covariant. Einstein concluded
by
emphasizing
the
drawbacks of
his
results: he had
neither
succeeded
in
writing
these
equations in
a
generally
covariant
form
nor
in
specializing generally
covariant
equations
in
such
a way
that
these
equations
follow.