Engines of Our Ingenuity


No. 1613:
FARADAY AND MAGNETISM

by John H. Lienhard

Click here for audio of Episode 1613.

Today, we watch genius at work. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

Calling any one person a genius is dangerous. Genius is not some gift to only a few; it resides in all of us. Still, few of us allow ourselves to reach down and fully tap into that mystical capacity. Michael Faraday was one person who did. Laying the foundation for the theory of electricity and magnetism was only one of his vast accomplishments.

Physicist John Tyndall was much younger than Faraday. He was also his friend and biographer. Tyndall had this to say about him:

When an experimental result was obtained by Faraday it was instantly enlarged by his imagination. I am acquainted with no mind whose power and suddenness of expansion at the touch of new physical truth could be ranked with his.

What Tyndall does here is offer a diagnosis of the process we so casually write off as genius. Faraday somehow let his mind be touched by nature in ways that few of us do.

I've often talked about how we gain knowledge in two very different ways: by gathering it in from the external world, or by creating it within our minds. Tyndall recognizes the almost magical way in which Faraday operated in both ways at once.

Tyndall tells how, around 1847, Faraday learned that the Italians had found that a flame responds to a magnetic field. Faraday said, "Flames are made of gas, but they also carry particles. Will a magnet affect a pure gas?" He could separate air into oxygen and nitrogen, but they were invisible. How might one see the effect of a magnet upon them? Faraday filled soap bubbles with oxygen and nitrogen, and floated them in a magnetic field. The oxygen bubbles moved one way in the field, the nitrogen bubbles moved the other.

Where then did lines of magnetic force lie? Did they have a neutral path through space? More experiments -- testing and rejecting more ideas. Finally, he was able to conclude that the true path of magnetic lines did lie in empty space, in a vacuum.

By the time Faraday had chased this interchange of logic and experiment to the end, he knew how magnetic fields behave. He'd determined that nitrogen is magnetically neutral -- that it acts very much like empty space. He'd explained magnetic storms. He'd shown how Earth's magnetic field is distorted by atmospheric oxygen. He'd rejected the ether hypothesis, long before it became such a source of mischief during the quantum revolution.

Tyndall stood in awe of Faraday's astonishing thought process -- a process that you and I might also put to use. So let's finish with his words.

The light, which was intellectual, enabled [Faraday] to see far beyond the boundaries of the fact itself, and the heat, which was emotional, urged him to the conquest of this newly-revealed domain. But though the force of his imagination was enormous, he bridled it like a mighty rider, and never [let] his intellect [be] overthrown.

I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work.

(Theme music)


Tyndall, J., Faraday as a Discoverer. London: Longmans, Green, and Co., 1868. See especially pages 108-119.

For a great deal more on Tyndall or Faraday, go to the Search command on the Engines home page and search on either name.



Michael Faraday (from the frontispiece of Tyndall's book on Faraday, above)


The Engines of Our Ingenuity is Copyright © 1988-2000 by John H. Lienhard.