  For a monopole, the analogue of the Lorentz equation in matter is shown to be
f = g (H - v cross D). Dual-symmetric Maxwell equations, for matter containing
hidden magnetic charges in addition to electric ones, are given. They apply as
well to ordinary matter if the particles possess T-violating electric dipole
moments. Two schemes of experiments for the detection of such moments in
macroscopic pieces of matter are proposed.
