"Whenever I teach a course on electromagnetism, one of the first ... exam questions I will ask students is, "Why is the magnetic field called H in the textbook?" ... The reason it is called H is, of course, Maxwell did not use the vector notation. He writes out all the components. So the electric field he starts with E ... And so, the electric field is E, F, G, and the magnetic field is, obviously, H, I, J. ... So all six components are written out. And so, it's very misleading for a textbook nowadays to say there are four Maxwell's equations. There were actually, if you look at Maxwell's papers, something like twenty-four equations. And the whole thing looks incredibly complicated."