Text: Maxwell's original theory used quaternions. The resultant scalar component of the interacting quaternions infolds functions of the interacting vectors, even when the vector resultant is zero. What today are called "Maxwell's Equations" are not so: not a one of those vector equations appears in any paper or book by James Clerk Maxwell. Instead, they are due to Oliver Heaviside (and to Hertz and Gibbs). Heaviside simply cut off the scalar component of the quaternion, reducing it to a vector. He wrote a subset of Maxwell's theory ­ specifically, the subset where EM and G are mutually exclusive. He threw away the part of Maxwell's theory where G and EM are entangled, and where EM can be turned into G and vice versa.

See Also:

Source: 132