Essays by A.T. Williams
Part I: Sneaking Up On Einstein
In physics, as elsewhere, the map is not the territory.
– A.T. Williams
Section 1 Section 2 Section 3 Section 4 Section 5 Section 6
Chapter 5: The Energetic Primordial Medium
Section 1: Beyond Electromagnetic Induction
Michael Faraday devoted his scientific career to discovering and describing in plain language the physical unity and interconvertibility of the diverse chemical, electrical, and magnetic forces manifested by, and through, particulate matter. After graduating from Trinity College, Cambridge, in 1854 mathematician James Clerk Maxwell embarked on his career by interpreting Faraday’s experimental results within the framework of classical (Newtonian) physics. Albert Einstein used Maxwell’s dynamical electromagnetic field theory as the foundation of his 1905 special theory of relativity.
In early 19th century England Faraday was an internationally renowned experimentalist without peer in physical chemistry, electricity, and magnetism. Both successful and unsuccessful experiments provided useful insights and information in his laboratory at the Royal Institution, London. Faraday made fundamental discoveries in electrochemistry, electrostatics, electricity, magnetism, and electromagnetism. The series of experiments which resulted in his discovery of electromagnetic induction in 1831 spanned a period of 10 years. 1
Elected to the Royal Society of London in 1824, Faraday became a charter member of the British Association for the Advancement of Science in 1831. 2 Ill health forced him to suspend his strenuous experimental schedule in 1839. At the British Association meeting following William Thomson’s 1845 graduation from Cambridge, Faraday asked Thomson’s opinion on the mathematics included in a paper he had received from Amedeo Avogadro in Italy. 3
Thomson, who later became Lord Kelvin, handily performed the task and asked three personal questions concerning dielectrics at the end of his 6 August 1845 written response. 4 Thomson’s questions intrigued Faraday and motivated him to resume his electromagnetic experiments. The new investigations into the great mystery of electromagnetism had barely resumed later that year when Faraday encountered an even greater mystery; namely, the mystery of the physical nature of magnetism per se.
An unsolved mystery:
Faraday’s electromagnetic experiments in the 1830’s were designed to discover the unifying principles underlying what seemed to be several kinds of electricity and magnetism. Electricity and magnetism per se were classified as imponderables belonging to one of the two kinds of physical substance recognized by classical 19th century natural philosophy (physics):
Ponderable matter: Material substance which has a nonzero mass, is capable of being weighed, and occupies space.
Imponderable matter: Material substance assumed to have a nonzero mass and occupy space, but which could not be weighed. For example:
Faraday’s new investigations motivated by Thomson’s dielectric questions in the letter of 6 August quickly expanded in scope. In a 1 November 1845 letter to William R. Grove, he wrote:
Royal Institution | 1 Novr. 1845
I am ashamed to say that I forgot until now to thank you on my wife’s part for the birds you sent her but I have been very busy & am so still – & the results or some of them you shall hear of shortly[.]
Ever Truly Yours | M. Faraday
W.R. Grove Esq | &c &c 5
Editor Frank A.J.L. James adds an explanatory footnote:
This was Faraday’s discovery of the magneto-optical [transmission] effect,6 that the state of polarization of light could be changed by a magnet when the light passed through a piece of heavy glass. He made this discovery on 13 September 1845 … following his failure to find a change in light passing through a transparent dielectric … and on which he had been working since. … The transparent bodies which he found displayed this property he quickly called ‘dimagnetics’7,8 … in analogy with dielectrics,… .9
The “heavy glass” James refers to in the footnote above was considerably more than a piece of ordinary glass. It had been specially manufactured by Faraday himself at the Royal Institution. Biographer Williams writes: “There were, in the laboratory, pieces of the heavy glass that Faraday had made back in 1830 for the Royal Society. This glass had an extraordinarily high refractive index, indicating that it acted powerfully upon light.”10
In his laboratory Diary, paragraph 7504, Faraday wrote:
A piece of heavy glass … which was 2 inches by 1.8 inches, and 0.5 of an inch thick, being a silico borate of lead, and polished on the two shortest edges, was experimented with. It gave no effects when the same magnetic poles or the contrary poles were on opposite sides (as respects the course of the polarized ray) – nor when the same poles were on the same side, either with the constant or intermitting current – BUT,* when contrary magnetic poles were on the same side, there was an effect produced on the polarized ray, and thus magnetic force and light were proved to have relation to each other. This fact will most likely prove exceedingly fertile and of great value in the investigation of both conditions of natural force . (Faraday’s emphasis)
* This word is underlined three times in the manuscript.11
Through this remarkable entry in his laboratory Diary we are privy to the method, the means, and the historical event on 13 September 1845 during which Faraday discovered the physical relationship between visible light (nonmaterial electromagnetic energy) and magnetism (nonmaterial magnetic energy). Note well that visible light is electromagnetic energy and magnetism is exclusively magnetic energy. In other words, magnetic energy per se is separate and distinct from the electromagnetic radiation spectrum.
By the time he penned a response to Sir John Herschel’s letter of 9 November,12 Faraday had tested the phenomenon thoroughly and was prepared to describe the new magneto-optical transmission effect to Herschel. On 13 November 1845, he wrote:
It was only the very strongest conviction that Light, Mag & Electricity must be connected that could have led me to resume the subject & persevere through much labour before I found the key. Now all is simplicity itself.
The results briefly are these[.] If certain transparent substances be placed between the poles of a magnet so that that line of power commonly called the Magnetic curve pass through them & a ray of polarized light be also passed through parallel to the line of magnetic force then the ray is rotated: if the line of Magnetic force pass one way the rotation is in one direction: if it pass the other way the rotation is in the contrary direction[.] If these same substances be placed in a helix & the electric current be sent round them whilst a polarized ray passes along the axis of the helix, it is in these substances rotated one way for one direction of the current the other way for the other direction[.] (Faraday’s emphasis)13
The magneto-optical transmission phenomenon was only the first of two new discoveries Faraday described in the letter to Herschel on 13 November 1845. In the last paragraph he revealed he also discovered a novel magnetic effect:
I have however (guided by my views of the action of magnets across dimagnetics: Exp Researches 1709-1736)14 discovered other means of examining the extraordinary state into which bodies generally are thrown by the magnetic forces, than their effect on a ray of light, and not only do doubly refracting crystals but opaque bodies – metals & I conclude all bodies come into subjection. … My next paper to the R.S [Royal Society]15 will contain an account of new magnetic actions & conditions of matter. (Faraday’s emphasis)16
James describes the word “dimagnetics” in the first sentence as “A slip of the pen for dielectrics.” Perhaps it was. There is no doubt Faraday was focused on the new magnetic actions and eager to get on with experimentally investigating the novel diamagnetic condition he had discovered in transparent and opaque ponderable bodies.
In a separate note James succinctly describes Faraday’s discovery of the diamagnetic condition in a transparent ponderable body:
On 4 November 1845, Faraday had discovered that a piece of heavy glass when hung between the poles of an electro-magnet aligned itself equatorially between the poles when the current was on. This he noted would probably allow him to extend dimagnetic properties into opaque bodies.17
Faraday later learned that the diamagnetic repulsion and the central axis equatorial alignment of opaque ponderable bodies had been observed and noted by several previous investigators, none of whom investigated the phenomenon further:
Brugmans first observed the repulsion of bismuth by a magnet in 1778.18 Coulomb appears to have seen a needle of wood set itself across a magnetic field; Edmond Becquerel reported the effect on wood in 1827, the same year that le Baillif published a paper on the magnetic repulsion of bismuth and antimony. In 1828 Seebeck reported the same effect with other substances. (L.Pearce Williams’ emphasis)19
Faraday’s experiments into the phenomenon of diamagnetism demonstrated that virtually every ponderable object is diamagnetic to one degree or another. In contrast to simply being either unaffected by, or attracted to, the strongest part of the magnetic field by aligning its central axis parallel to the magnetic field lines like an ordinary magnet, he discovered that in a sufficiently strong magnetic field virtually every ponderable material object behaves diamagnetically.
That is to say – and this is crucial to understanding the phenomenon – virtually any material object will be repelled by a sufficiently strong magnetic field, and the object will seek the weakest point of that incident magnetic field while aligning its central axis perpendicular (90 degrees) to the incident magnetic lines of flux.
Recognizing that his experimental results pertaining to diamagnetism would require a broader classification of imponderable magnetic phenomena, Faraday contacted his learned friend, William Whewell. Whewell suggested the continued use of the term “diamagnetic” to indicate the new properties and adding the term “paramagnetic” to indicate previously known magnetic properties, thereby dividing magnetic phenomena into two classes. Ferromagnetic, antiferromagnetic, and ferrimagnetic phenomena, among others, have been added to the list over the past 150 years.
Continued in Section 2: The Map Is Not The Territory
Reference Notes (Click on the Note number to return to the text):
1 Joseph Henry, working independently in the United States, also discovered electromagnetic induction in 1831. Faraday published his experimental results before Henry did, thus Faraday received the priority (credit) for making the discovery.
2 Williams, L. Pearce. Michael Faraday, A Biography, p. 355. Da Capo Press, Inc., New York, NY, 1965. ISBN 0-306-80299-6
3 James, Frank A.J.L., editor. The Correspondence of Michael Faraday, Volume 3, 1841-1848, Letter 1674, pp. 317-318. The Institution of Electrical Engineers, London, United Kingdom, 1996. ISBN 0-86341-250-5
4 Ref. 3, Letter 1765, William Thomson to Faraday, p. 406.
5 Ref. 3, Letter 1779, Faraday to William Robert Grove, p. 421.
6 There is a distinct difference between the Faraday magneto-optical transmission effect discovered by Michael Faraday in 1845 (the Faraday effect), and the Kerr magneto-optical reflection effect discovered by John C. Kerr in 1875 (the Kerr effect).
7 Ref. 3, Letter 1797, Faraday to William Whewell, p. 441.
8 Ref. 3, Letter 1798, William Whewell to Faraday, p. 442:
As to the name for the antithetical classes of bodies, I consider thus. I suppose you called one class dimagnetic from analogy with dielectric. I think you ought to have said diamagnetic; for the bodies through (dia) which electricity goes would have been called diaelectric, but that vowels in such cases coalesce. I think you may keep diamagnetic for this class, and give to the opposite class a name implying that they rank along with magnetic bodies. I propose paramagnetic. (Whewell’s emphasis)
9 Ref. 3, Letter 1779, footnote 1, p. 421.
10 Ref. 2, p. 386.
11 Ref. 2, p. 386.
12 Ref. 3, Letter 1783, John Frederick William Herschel to Faraday, pp. 423-425.
13 Ref. 3, Letter 1784, Faraday to John Frederick William Herschel, p. 426.
14 Faraday, Michael. Experimental Researches in Electricity , vol. 1, Fourteenth Series, sec. 21, pp. 545-552. Green Lion Press, Santa Fe, NM, 2000. 3 volume Set, ISBN 1-888009-15-2
For a more precise reference in his laboratory Diary, it was Faraday’s custom to reference the paragraph numbers of material previously published in ERE rather than page numbers.
15 Ref.3, p. 427.
16 Ref. 14, vol 3, Twentieth Series, pp. 27-53.
17 Ref. 3, pp. 427-428.
18 Brugmans, Anton. Philosophische Versuch über die magnetische Materie, und deren Wirkung in Eisen und Magnet. Leipzig, 1784.
19 Ref. 2, p. 393. (cf., ERE, vol. 3, p. 82.)
Back to Chapter 4: Faraday, Maxwell, and Newtonian Physics.
Index: Consciousness, Physics, and the Holographic Paradigm.
Last Edit: June 22, 2006.
Comments and suggestions welcome.
This paper is a work in progress.
Please check for the latest update before quoting in other venues the concepts and hypotheses presented here.
Copyright © 2002-2008 by Alan T. Williams. All rights reserved.