And an Introduction to Fields. Normally, new Fields & Energy posts appear on Wednesday mornings. And yet, here we are, a day early, on Tuesday March 12, 2024. Why? Because today is the 192nd anniversary of what is arguably the single most important day in electromagnetic history. What happened on March 12, 1832? And why don’t more people know about it? Read on!
So were Michael Faraday's lines of forces defining a force field, as understood in the eighteenth century, or a new form of matter, as became understood after the work of James Clerk Maxwell?
It would take some work to pin down their exact opinions. I recall Faraday spoke of lines of force as a "truthful representation." I don't believe Maxwell or any of his contemporaries regarded them as physically real entities in and of themselves, except in so far as they represented physically real stresses or strains or tensions in the aether. Maxwell disavowed the reality of his aether models except to the extent he affirmed that energy is stored in free space. That he meant to be taken literaly. I found a good essay by FitzGerald I'm going to reprint in a few weeks on this subject:
Ye Olde sailors (Phoenician merchants) used the lodestone to find their way esp. at night using Polaris. Originally amber exhibited electric properties when rubbed (from whence the term 'electron'), but it has been proposed the ancients used a rudimentary but perfectly viable form of compass; a (magnetite) lodestone with iron filings.
Which walks straight in to Don Scott's modelling of a Birkeland current (https://www.youtube.com/watch?v=yIFR67sckK0) whereby one can imagine our planet aligned with Polaris across those vast distances and the sailors tapping in to that natural power. This is how metaphysics functions in our deepest reality too. But as Aristotle's publisher supposedly said, we ought to know the physics before the metaphysics. Great post.
The earliest firm dates we have on using compasses for navigation date to the thirteenth century, and there's some dispute whether ir originated in Europe or in China. I was not aware there was such good evidence for a much earlier use of a compass. Thanks for sharing and for your kind words.
Faraday's 'field' was a concept, an idea, or a form - something that Aristotle greatly opposed. If anything, I would think, Faraday's physics was anti-Aristotelian.
That's not the interpretation I take away from Faraday's writing...
Faraday did not regard lines of force as merely an abstraction, however. He believed his lines of force corresponded to actual physical behavior.
"...I cannot refrain from again expressing my conviction of the truthfulness of the representation, which the idea of lines of force affords in regard to magnetic action. All the points which are experimentally established with regard to that action, i.e. all that is not hypothetical, appear to be well and truly represented by it."
Faraday hypothesized physical mechanisms that might underlie the behavior of fields, although he was unable to demonstrate them to his satisfaction. Fields were more than just a conceptual abstraction of idea to him.
So were Michael Faraday's lines of forces defining a force field, as understood in the eighteenth century, or a new form of matter, as became understood after the work of James Clerk Maxwell?
It would take some work to pin down their exact opinions. I recall Faraday spoke of lines of force as a "truthful representation." I don't believe Maxwell or any of his contemporaries regarded them as physically real entities in and of themselves, except in so far as they represented physically real stresses or strains or tensions in the aether. Maxwell disavowed the reality of his aether models except to the extent he affirmed that energy is stored in free space. That he meant to be taken literaly. I found a good essay by FitzGerald I'm going to reprint in a few weeks on this subject:
https://archive.org/details/scientificwriti00fitzgoog/page/162/mode/2up
I see Kirk McDonald recently wrote an excellent essay on this subject as well:
http://kirkmcd.princeton.edu/examples/fieldlines.pdf
Ye Olde sailors (Phoenician merchants) used the lodestone to find their way esp. at night using Polaris. Originally amber exhibited electric properties when rubbed (from whence the term 'electron'), but it has been proposed the ancients used a rudimentary but perfectly viable form of compass; a (magnetite) lodestone with iron filings.
https://www.researchgate.net/figure/Proposed-replica-of-the-Magnetic-Compass-with-lodestone-magnetite-A-E-A-Wooden_fig2_273125430
Which walks straight in to Don Scott's modelling of a Birkeland current (https://www.youtube.com/watch?v=yIFR67sckK0) whereby one can imagine our planet aligned with Polaris across those vast distances and the sailors tapping in to that natural power. This is how metaphysics functions in our deepest reality too. But as Aristotle's publisher supposedly said, we ought to know the physics before the metaphysics. Great post.
The earliest firm dates we have on using compasses for navigation date to the thirteenth century, and there's some dispute whether ir originated in Europe or in China. I was not aware there was such good evidence for a much earlier use of a compass. Thanks for sharing and for your kind words.
Faraday's 'field' was a concept, an idea, or a form - something that Aristotle greatly opposed. If anything, I would think, Faraday's physics was anti-Aristotelian.
That's not the interpretation I take away from Faraday's writing...
Faraday did not regard lines of force as merely an abstraction, however. He believed his lines of force corresponded to actual physical behavior.
"...I cannot refrain from again expressing my conviction of the truthfulness of the representation, which the idea of lines of force affords in regard to magnetic action. All the points which are experimentally established with regard to that action, i.e. all that is not hypothetical, appear to be well and truly represented by it."
Faraday hypothesized physical mechanisms that might underlie the behavior of fields, although he was unable to demonstrate them to his satisfaction. Fields were more than just a conceptual abstraction of idea to him.