Abstract

The existence of longitudinal forces between elements of electrical current was claimed by the earliest investigator, Ampere, but has been denied by modern relativistic theory. Until recently, experimental difficulties have prevented an empirical resolution of the issue. In the last decade, however, applications of a method, termed ?inertial modulation? of force, have made it possible to circumvent the difficulties, and clear resolution has emerged in favor of Ampere. It thus appears that electrodynamic forces violate the universal covariance of relativity.