Vector analysis and the vector form of the field equations
The modern vector language in which the four familiar equations of the electromagnetic field are written today. Maxwell himself had written the field relations mostly in Cartesian components, scattered across many articles of the Treatise; he gave quaternion expressions only as a separate summary he barely used.
In 1884-1885 the Englishman Oliver Heaviside recast Maxwell's theory in vector notation, threw out the potentials and kept only the fields E and H, and four recognisable equations are already visible in his work, although he never gathered them into a single group of four and reserved the name 'duplex' for the coupled pair of curl formulas. Heaviside built his vector calculus himself, at the same time as the American Josiah Willard Gibbs, who reached a similar system earlier but published later. The German Heinrich Hertz arrived independently at the same duplex form and himself conceded priority to Heaviside, which is why people long spoke of the Maxwell-Hertz equations, as Einstein still does in 1905.
On Arthur's reading, it was only the Dutchman Hendrik Lorentz in 1902 who assembled the four into one fundamental set in the form familiar today. That is, the content of the equations is Maxwell's, the vector language is Heaviside's, and the canonical set of four took shape later still.
Why this date
The year is counted from the series 'Electromagnetic Induction and Its Propagation', which Heaviside began publishing in the London journal The Electrician in 1885; by his own account he had been using his vector algebra in papers from 1883 onward, so the period is given as 1884-1885. Sources differ on how the equations are counted: Hunt assigns twenty equations to the 1873 Treatise, Rautio speaks of twenty equations in twenty variables without tying the count to a particular text, Wheeler describes the Treatise as relations scattered over more than twenty pages across two chapters, and Donaghy-Spargo counts twenty-two and moreover calls the original notation quaternionic, unlike Crowe, Hunt and Wheeler.
What it grew from
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Hamilton's quaternions
improved · Confidence: high
The vector analysis of Gibbs and Heaviside was obtained by directly simplifying the quaternion calculus: both came to it through quaternion texts and both discarded the union of scalar and vector parts into a single product, after which quaternions were displaced from physics without ever being refuted.
Dispute: Quaternions were never shown to be false: they were displaced by a more convenient notation, while the algebra itself stayed valid. Historians differ on whether vector analysis was a direct descendant of quaternions. Crowe documents the actual route: both Gibbs and Heaviside came to vectors through the quaternion texts of Tait and Maxwell. Heaviside himself, by contrast, claimed that vector analysis could have been derived by any mathematician directly from the mechanics of Cartesian mathematics, without quaternions at all, and on that reckoning the dependence would be indirect only.
Link sources
- Oliver Heaviside, quoted in Bruce J. Hunt, Oliver Heaviside: A First-Rate Oddity, Physics Today 65 (11), 48-54 (2012) Verified 20 Sep 2026
I dropped out the quaternion altogether, and kept to pure scalars and vectors, using a very simple vectorial algebra in my papers from 1883 onward.
- J. Willard Gibbs, quoted in Michael J. Crowe, A History of Vector Analysis (lecture text), p. 12 (2002) Verified 20 Sep 2026
where Quaternion notations are considerably used, I became convinced that to master those subjects, it was necessary for me to commence by mastering those methods.
- Michael J. Crowe, A History of Vector Analysis (lecture text), p. 16 (2002) Verified 20 Sep 2026
by 1910, the Gibbs-Heaviside, i.e., the modern system had won out in the struggle for existence
- Simon L. Altmann, Hamilton, Rodrigues, and the Quaternion Scandal, Mathematics Magazine 62 (5), 291-308, p. 306 (1989)
nothing that they did, however, succeeded in preventing the rise of vectors and the consequent decline of quaternions
"Verified" means that on that day the quotation was found at the address given, word for word. No date means we have not been able to open the source yet, not that the quotation is wrong.
- Oliver Heaviside, quoted in Bruce J. Hunt, Oliver Heaviside: A First-Rate Oddity, Physics Today 65 (11), 48-54 (2012) Verified 20 Sep 2026
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Maxwell's electromagnetic theory of light
improved · Confidence: medium
In 1884-1885 Heaviside recast Maxwell's electromagnetic theory in vector notation, removing the potentials and keeping only the fields, and it is out of that notation of his that the form of the field equations familiar today grew.
Dispute: Both the count of the original equations and the question of who produced the canonical set of four are contested. Hunt assigns twenty equations to the 1873 Treatise, Rautio speaks of twenty equations in twenty variables, Donaghy-Spargo of twenty-two, and Wheeler describes them as scattered over more than twenty pages. The short formula that Heaviside gave the equations their modern form comes mainly from popular accounts (Rautio); Arthur's detailed study shows that Heaviside never gathered the four into one group, that he reserved the name 'duplex' for the pair of curl formulas, that Hertz reached the same form independently and conceded priority to Heaviside, and that the four were first given as a single fundamental set by Lorentz in 1902. The role of quaternions is disputed separately: Brezov (2025) writes that Maxwell derived his equations using Hamilton's quaternion differential calculus, whereas Crowe, Hunt and Wheeler hold the opposite, that the main notation was Cartesian component form and that Maxwell was nearly indifferent to the quaternion expressions.
Link sources
- James C. Rautio, The Long Road to Maxwell's Equations, IEEE Spectrum 51 (12), 36 (2014) Verified 20 Sep 2026
It was Heaviside, working largely in seclusion, who put Maxwell's equations in their present form.
- Oliver Heaviside, quoted in James C. Rautio, The Long Road to Maxwell's Equations, IEEE Spectrum 51 (12), 36 (2014) Verified 20 Sep 2026
I never made any progress until I threw all the potentials overboard
- Bruce J. Hunt, Oliver Heaviside: A First-Rate Oddity, Physics Today 65 (11), 48-54 (2012) Verified 20 Sep 2026
In 1884–85 Oliver Heaviside rewrote the 20 fundamental equations of Maxwell's Treatise on Electricity and Magnetism into a new and more compact form that by the late 1890s had become standard.
- John W. Arthur, The Evolution of Maxwell's Equations From 1862 to the Present Day, IEEE Antennas and Propagation Magazine 55 (3) (2013) Verified 20 Sep 2026
nor did he even put the four main equations together into a single group as we know them now, but what he produced did contain four familiar looking equations
"Verified" means that on that day the quotation was found at the address given, word for word. No date means we have not been able to open the source yet, not that the quotation is wrong.
- James C. Rautio, The Long Road to Maxwell's Equations, IEEE Spectrum 51 (12), 36 (2014) Verified 20 Sep 2026
Node sources
- James C. Rautio, The Long Road to Maxwell's Equations, IEEE Spectrum 51 (12), 36 (2014) Verified 20 Sep 2026
It was Heaviside, working largely in seclusion, who put Maxwell's equations in their present form.
- Bruce J. Hunt, Oliver Heaviside: A First-Rate Oddity, Physics Today 65 (11), 48-54 (2012) Verified 20 Sep 2026
In 1884–85 Oliver Heaviside rewrote the 20 fundamental equations of Maxwell's Treatise on Electricity and Magnetism into a new and more compact form that by the late 1890s had become standard.
- Bruce J. Hunt, Oliver Heaviside: A First-Rate Oddity, Physics Today 65 (11), 48-54 (2012) Verified 20 Sep 2026
Maxwell had written most of his equations in Cartesian coordinates, which yielded long and complicated expressions for such things as the curl of a flux.
- John W. Arthur, The Evolution of Maxwell's Equations From 1862 to the Present Day, IEEE Antennas and Propagation Magazine 55 (3) (2013) Verified 20 Sep 2026
nor did he even put the four main equations together into a single group as we know them now, but what he produced did contain four familiar looking equations
- John W. Arthur, The Evolution of Maxwell's Equations From 1862 to the Present Day, IEEE Antennas and Propagation Magazine 55 (3) (2013) Verified 20 Sep 2026
the only identifiable 'special set' seems to be (III) and (IV) which, because of their cross-coupling, he called the 'duplex equations'
- John W. Arthur, The Evolution of Maxwell's Equations From 1862 to the Present Day, IEEE Antennas and Propagation Magazine 55 (3) (2013) Verified 20 Sep 2026
he gave us Maxwell's equations as a fundamental set for what appears to be the first time
- Heinrich Hertz, quoted in John W. Arthur, The Evolution of Maxwell's Equations From 1862 to the Present Day, IEEE Antennas and Propagation Magazine 55 (3) (2013) Verified 20 Sep 2026
In this respect, Mr. Heaviside has the priority.
- Christopher Donaghy-Spargo, On Heaviside's contributions to transmission line theory: waves, diffusion and energy flux, Phil. Trans. R. Soc. A 376, 20170457 (2018)
Heaviside was first to recast the 22 Maxwell equations into this Vector algebra form, as is common today in almost all textbooks on the subject
- Nicholas Wheeler, Theories of Maxwellian Design, Reed College Physics Department (1998) Verified 20 Sep 2026
scattered throughout more than twenty pages of text spanning two chapters
- A. Einstein, Zur Elektrodynamik bewegter Körper, Annalen der Physik 17, 891-921, § 6 (1905) Verified 20 Sep 2026
Transformation der Maxwell-Hertzschen Gleichungen für den leeren Raum.
"Verified" means that on that day the quotation was found at the address given, word for word. No date means we have not been able to open the source yet, not that the quotation is wrong.