  Electromagnetic properties of a simple polarisable medium may be
parameterised in terms of a constitutive tensor whose properties can in
principle be determined by experiments in non-inertial (accelerating) frames
and in the presence of weak but variable gravitational fields. After
establishing some geometric notation, discussion is given to basic concepts of
stress, energy and momentum in the vacuum where the useful notion of a drive
form is introduced in order to associate the conservation of currents involving
the flux of energy, momentum and angular momentum with spacetime isometries.
The definition of the stress-energy-momentum tensor is discussed with
particular reference to its symmetry based on its role as a source of
relativistic gravitation. General constitutive properties of material continua
are formulated in terms of spacetime tensors including those that describe
magneto-electric phenomena in moving media. This leads to a formulation of a
self-adjoint constitutive tensor describing, in general, inhomogeneous,
anisotropic, magneto-electric bulk matter in arbitrary motion. The question of
an invariant characterisation of intrinsically magneto-electric media is
explored. An action principle is established to generate the phenomenological
Maxwell system and the use of variational derivatives to calculate
stress-energy-momentum tensors is discussed in some detail. The relation of
this result to tensors proposed by Abraham and others is discussed in the
concluding section where the relevance of the whole approach to experiments on
matter in non-inertial environments with variable gravitational and
electromagnetic fields is stressed.
