  In this paper we considered divergence of electric and of magnetic fields for
four cases: classical point charge, classical continuous charge, relativistic
point and relativistic continuous charges. Results for classical and
relativistic point charges are the same as in literature, i.e. Gauss's law is
valid. However results for time-varying classical and relativistic distributed
charges indicate that divergence of electric field is not zero even for volumes
of space where no charges are present. For these cases original Gauss's law
might require modification. Divergence of electric field seems to be far-field
type scalar anisotropic field, which is generated by time-varying electric
charges or currents. Results indicate that for these effects to be sufficiently
large to be experimentally observable the time variation of electric charges
and/or of currents should be very fast. Divergence of magnetic field is zero
for all cases.
