Electromagnetism and semantics

The terminology still in common use by many writers on electromagnetic topics is unconsciously related to the original Maxwell ether model, which gives the E, D, B and H vectors equal status as a set of four fundamental field quantities. Maxwell´s equations are usually presented in terms of all four quantities, together with the `constitutive relationships of the medium´. This is an unnecessarily complicated and physically unrealistic approach, which is a source of much confusion both in students and in practising engineers. Observation demonstrates that only three axioms underlie classical electromagnetism: the invariance of electric charge, Coulomb´s law, and the constancy of the velocity of light. These axioms lead to Maxwell´s equations via special relativity and the Lorentz transformation; i.e. without any necessity for an ether concept. Further consideration of the physical implications leads to a strong recommendation that the continued use of semantically misleading terminology, such as `magnetic field strength H´ or `the permittivity of free space´, should be discouraged. A tentative glossary of acceptable terminology is put forward for consideration by teachers and by authors