Editing Metric system (section)

=== Rationalisation ===
Maxwell's equations of electromagnetism contained a factor of <math>1/(4\pi)</math> relating to [[steradian]]s, representative of the fact that electric charges and magnetic fields may be considered to emanate from a point and propagate equally in all directions, i.e. spherically. This factor made equations more awkward than necessary, and so [[Oliver Heaviside]] suggested adjusting the system of units to remove it.<ref name=":1" />