  We consider a mechanism by which dyons (electrically charged magnetic
monopoles) can produce both a T- and P-odd (i.e. time reversal invariance and
parity violating) mixed polarizability beta [defined by Delta E = -beta E.B,
where Delta E is the energy change when electric (E) and magnetic (B) fields
are applied to a system] and a T- and P-odd interaction between two particles:
psi_1-bar gamma_5 psi_1 psi_2-bar psi_2, where the psi_i are electron and quark
spinors. The latter can create atomic and neutron electric dipole moments
(EDMs). From experimental bounds on these we find limits on the properties of
dyons. Our best limit, using the experimental limit for the EDM of the Tl atom,
is M |Q g (Q^2 - g^2)|^(-1/4) > 6 GeV, where M is the dyon mass and Q is the
electric and g the magnetic charge of the dyons. The contribution of dyons to
CP violation in K-meson decays is also estimated.
