AmpereÕs Law: Flux of mahnetic field through a closed surface is zero; therefore, there are no magnetic monopoles.

GaussÕ Law (early 1800s): Flux of electric field through a closed surface is proportionally equal to the charge inside.

FaradayÕs Law (1831): Electrioc field is induced by a changing magnetic field (magnet in a coil experiment).

MaxwellÕs equations (mid-1800s): Unified light and electricity/magnetism.

OhmÕs Law: A discontinuous E-field at a boundary in conductivity.  Charges build at the boundaries.