13.1. A Tiny Bit More of Faraday

One can wonder how the study of electricity and magnetism might have evolved had Michael Faraday become the bookbinder that he was apprenticed to be. He might have led a fine life, surely a better one than his parents’, had a family, and maybe introduced some innovative techniques to the printer trade. Then Ampere, Biot, Volta, Green, Weber, Henry, Kirchhoff, Thomson, Davy, and the others would have continued their researches which would have required them to eventually break from their firmly entrenched training and biases. The field idea would have eventually emerged somehow and James Maxwell, whom we’ll meet in the next lesson, would surely have played a role. But the world would not have had Faraday’s extensive laboratory notebooks which he periodically published and so all of the experimentation he’d done by himself would have to come from probably many other scientists.

And maybe, had Charles Wheatstone stood his ground and not fled in the face of a particular critic in the audience on an otherwise regular Friday Evening Discourse, Faraday’s path to the field idea might have been different. Wheatstone was a scientist and engineer who was notoriously shy and allergic to controversy. He had been invited to give a talk at the Royal Institution Friday series on the evening of April 3rd in 1846. These public talks generally drew hundreds of everyday people drawn to learn the scientific wonders of the day. On that particular evening Wheatstone saw a fellow in the audience who had a reputation for heckling presenters and he turned on his heel and fled into the dark, springtime city streets leaving Faraday alone on the stage with nothing to say. What he did changed everything.

For a bit, he tried to summarize Wheatstone’s work, probably unsatisfactorily. And then he started to chat off the cuff, presenting a “vague impression of his mind.” Let’s remember what the known-knowns were at the time. His demonstrations had shown that “lines of force” were present around permanent magnets, wires carrying currents, and distributions of electrically charged objects. These lines of force were real enough to twist bits of iron and line them up and twist bits of pollen and likewise cause them – unassisted from any visible source – to reveal a smooth pattern. That was known. Faraday had ideas about atoms being the cause of the lines of force, as he had become the world’s expert on electrochemistry and electrolysis for which an atomic picture can be useful. But he wasn’t prepared to totally commit to that idea.

Furthermore, everyone shared Newton’s disdain of Action at a Distance in gravitation – but nobody could offer an alternative explanation and so it lingered like a relative who is a general family embarrassment.

However, Action at a Distance was threatening to raise its head in the electrostatics and magnetism game and Faraday was having none of it. Nobody was. Another known-known was that light had turned out to be a wave phenomenon after Thomas Young (at the Royal Academy also) demonstrated it. That led to a collective nervous breakdown in scientific Britain, driving Young from science altogether but eventually ginning up the idea of a “luminiferous ether” as the all-pervasive substance that supported the vibrations of light waves. What did light wave? Why the ether is what physically waved. That became the model of light and Faraday was having none of it.

“The velocity of light through space is about 190,000 miles in a second; the velocity of electricity is, by the experiments of Wheatstone, shown to be as great as this, if not greater: the light is supposed to be transmitted by vibrations through an ether which is,… infinite in elasticity; the electricity is transmitted through a small metallic wire, and is often viewed as transmitted by vibrations also. That the electric transference depends on the forces or powers of the matter of the wire can hardly be doubted…”

But the matter in a copper wire has weight, but the ether doesn’t. If both are made of particles, they are very, very different. But the same.

The bottom line for Faraday, which he then had to defend multiple times afterwards was that the lines of force were the reality. Not an ether. He subsequently dubbed the reality a “field” and that name has stuck, of course to this day.

“For suppose two bodies, A B, distant from each other and under mutual action, and therefore connected by lines of force, and let us fix our attention upon one resultant of force having an invariable direction as regards space; if one of the bodies move in the least degree right or left, or if its power be shifted fora moment within the mass (neither of these cases being difficult to realize if A and B be either electric or magnetic bodies), then an effect equivalent to a lateral disturbance will take place in the resultant upon which we are fixing our attention; for, either it will increase in force whilst the neighbouring resultants are diminishing, or it will fall in force as they are increasing.”

He’s basically saying that A creates a field between it and B…wiggle A and B, a finite time later, will wiggle. What’s between them, that propagates the wiggle is his field. And it’s real. And furthermore, the field is a property of space itself – it, not atoms (“centers of force”) – was the field’s home. No ether, just space suffused with interweaving waves of electricity, magnetism, and yes, gravity. His was a theory of everything, or more correctly, a picture of everything.

Two days later he wrote

I think it likely that I have made many mistakes in the preceding pages, for even to myself, my ideas on this point appear only as the shadow of a speculation, or as one of those impressions on the mind which are allowable for a time as guides to thought and research. He who labours in experimental inquiries knows how numerous these are, and how often their apparent fitness and beauty vanish before the progress and development of real natural truth.

Reaction was swift:

“Faraday’s achievements are due to his immense earnestness and great love for his subject and this very mistiness which serves to obscure the verity of matters may have its compensations by rendering the subject attractive and thus wooing a man to work at it with more fervour.” Tyndall

“…he could not understand Faraday, and if you look for exact knowledge in his theories you will be disappointed—flashes of wonderful insight you meet here and there, but he has no exact knowledge himself, and in conversation with him he readily confesses this.” Biot

Friends and colleagues condescendingly suggested that he should leave the mathematics to the professionals. Everyone respected his experimental skill, and like his successor, Tyndall above, his imagination. But this time he’d gone too far. Let’s see.