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Commentary on Ritz's Electrodynamics

Given at the

Natural Philosophy Alliance Meeting - February 14, 1998 - Philadelphia PA
Robert S. Fritzius, 305 Hillside Drive, Starkville, MS 39759 U.S.A.

Installed 30 Nov 1998 - Latest Update 07 Jun 2017
Updated material is in bold.


In 1908 Walter Ritz identified seven areas of difficulty with regard to the Maxwell-Lorentz electromagnetic field equations, which are based on the concept of a solid deformable ether. (1) Electric and magnetic forces really express relations about space and time and should be replaced with non-instantaneous elementary actions (his emission theory). (2) Advanced potentials don't exist (and their erroneous use led to the Rayleigh-Jeans ultraviolet catastrophe). (3) Localization of energy in the ether is vague. (4) It is impossible to reduce gravity to the same notions. (5) The unacceptable inequality of action and reaction is brought about by the concept of absolute motion with respect to the ether. (6) Apparent relativistic mass increase is amenable to a different interpretation. (7) The use of absolute coordinates, independent of all motions of matter, requires throwing away the time honored use of Galilean relativity and our notions of rigid ponderable bodies.


Historians of science generally recognize three early contenders in the quest for a relativity theory consistent with the null result of the Michelson-Morley experiment. These were H.A. Lorentz, Henri Poincaré, and Albert Einstein. We might call these the three musketeers of relativity.

It is not so well known but there was a relativity D'Artagnan as well. He was Swiss physicist Walter Ritz. But Ritz died in battle and it seems as though the Cardinal placed his ideas under the ban. They do, however, surface from time to time.

This presentation, which is done in the spirit of "lifting the ban," combines selected comments about Ritz's work by William Hovgaard, of M.I.T., in 1932 and by Myron Evans, of Wales, in 1997 [Professor Evans is the Director of the Alpha Foundation Institute for Advanced Study (AIAS).] I'll inject a few remarks to enlarge on certain topics.

The Evans material is from his running commentary of a 1980 translation of Ritz's 1908 critique on Maxwell-Lorentz. The quotes from his commentary are used with his kind permission. Evans, who is pro-Einstein on relativity, generated his commentary from front-to-back, one section at a time. He found a surprise when he got to Ritz's relativistic considerations on mass, length, and time.

Selected Hovgaard Comments on Ritz

Lorentz, the first of our relativity musketeers, stressed the fact that his system of partial differential equations, was tied to the concept of a solid ether electromagnetic field. (L1)

[Hovgaard] Lorentz regarded the ether as immobile... The earth was conceived as moving through the ether without disturbing it and it followed that there must be an "ether drift," which it should be possible to detect. But this proved impossible. ...It was felt necessary to resort to new hypotheses. [Enter musketeers number two and number three.]

Poincaré proposed to use Galilean relativity to resolve the problem. (The speed of light c is relative to the source.) The sources and detectors were moving at the same velocity, hence no speed of light variations were detected.

[Hovgaard] Einstein ... interpreted the Michelson-Morely experiments as showing simply that the velocity of light was the same for an observer in motion as for one at rest.(This is Einstein's second postulate of special relativity.)

In 1921 Einstein asserted, "The space-time theory and the kinematics of the special theory of relativity were modelled on the Maxwell-Lorentz theory of the electromagnetic field. (E1)


Enter the relativity D'Artagnan.

Walter Ritz

Walter Ritz, 1878 - 1909

In his detailed 1908 critique of Maxwell-Lorentz theory, Ritz concluded that:

"The [Maxwell-Lorentz] partial differential equations and the notion of ether are essentially inappropriate to express the comprehensive laws for the propagation of electrodynamic actions."(172)

If Ritz's conclusion comes to be validated, then we are justified in looking for those other creeks in which to paddle.


[Hovgaard] In 1908 [Ritz] published his first and most comprehensive memoir on electrodynamics ... in which he subjected Maxwell's theory, as modified by Lorentz, to a critical analysis and outlined a new theory of electrodynamics. This memoir was followed by several papers on the same and allied subjects such as the theory of the ether and of gravitation. (H1-218)

[Ritz] Experiment has shown that [electrodynamic] actions are not instantaneous; also it hasn't revealed any trace of a medium which could exist in materially empty space. I therefore felt I could restrict myself to give to the law of propagation of these actions, a very simple kinematic interpretation, borrowed from the [Newtonian] emanative theory of light and satisfying the principle of relativity of motion. [This is the same relativity principle as proposed by Poincaré.]

[Ritz] Fictitious particles are constantly emitted in all directions by electric charges. They keep on moving indefinitely in straight lines with constant speed, even through material bodies. The action undergone by a charge depends uniquely on the disposition, velocity, etc. of these particles in its immediate surroundings.(150)

Ritz claimed that his mathematical model was exactly equivalent to Lorentz's version of Maxwell. (He didn't get into the nuts and bolts of how the actions were generated.) If he got the job done though, if his model really is equivalent to Maxwell- Lorentz, then problems with his model are also problems with Maxwell-Lorentz. ...

[Hovgaard] Ritz proposed ...complete abandonment of the ether. Lorentz and FitzGerald advanced the so-called "contraction hypothesis." according to which all bodies should contract when they move through the ether..... Lorentz accepted Einstein's theory, [the second postulate]and attempted at the same time to uphold the theory of the ether, but this led to highly artificial and complicated conceptions both in electrodynamics and optics. (H1-219,220)

In keeping with Maxwell-Lorentz principles Ritz observed strict adherence to the superposition theorem in his (1908) reasonings. (The superposition theorem says that charged material particles, protons, electrons, etc., don't get in the way of one another or cause reactive effects on the source field . Supposedly there is no decrease in a charge's ability to affect distant charges as a result of its actions imparted to intervening charges ). Ritz claimed the superposition viewpoint was not in accordance with experimental evidence, and because of this, his temporary version of Lorentz's views would be flawed with regard to the speed of light in dispersive media.

Evans' Comments on

Critical Researches on General Electrodynamics

Introduction. (145-152)

(The page and section numbering used here are from Ritz's original article.)

[Evans] Ritz set out to make incisive and helpful criticisms of the state of electrodynamics, advocating the use of elementary actions rather than fields. He traces difficulties, which he ascribes to a common origin, the concept of ether, and uses the theory in the form given by Lorentz. This is the same in most if not all textbooks now as in 1908. So the difficulties perceived then are there now.

[Evans] On page 146 {Ritz} notes that electric and magnetic fields can be eliminated entirely from the Maxwell-Lorentz theory and represent only relations of space and time, ... He advocates a return to elementary actions with the sole difference that they are not instantaneous (i.e. retarded potentials). He notes on p. 147 that the [electromagnetic] field theory [characterized by continuum partial differential equations] admits an infinite number of solutions, only some of which are physical. The retarded potential formalism eliminates unphysical solutions and introduces irreversibility in time, while the field equations allow reversibility.

1. - Recall of Lorentz's Theory. (152-159)

[Evans] The Maxwell Lorentz [field] theory (when integrated using retarded Newtonian potentials) is delayed action at a distance. The only difference from the older Clausius and Weber theories is that action in these theories is instantaneous.. (157)

Part 2

2. - Criticism of notions of Electric and Magnetic Fields. (159-163)

[Evans] They really express relations about space and time

[Ritz] ".....the field never plays a role in pure ether. In fact, we can only determine the field's magnitude and direction by placing a body and observing the mechanical forces that it feels or rather its motions and those of the ions in its near vicinity, motions which are indicated by luminous, thermal, chemical, etc. phenomena. Therefore we know only F (force), and that only in points of x, y, z where there is electrified matter, and we deduce E and H by reasoning ... . This is to say that it will suffice, in all cases, to know the formula that gives F as the result of elementary actions exerted by an element of charge on another element of charge, and that this second representation is, with regard to the facts, exactly equivalent to the first one, which is based on the field and its partial differential equations which only play a purely mathematical role. We can if we please, dispense completely with the notions of electric and magnetic fields."(161)

3. - Irreversibility and Retarded Potentials. (163-172)

Maxwell's field equations, which are based on the idea of a solid ether, admit time reversible solutions. Ritz held that electromagnetic phenomena are, in general, irreversible because of radiation.(164)

He claimed that advanced potentials (future states affecting the present, i.e. supplying energy to run present processes) have no place in reality.(164) (In a later paper he stated that the Rayleigh-Jeans ultraviolet catastrophe derived from this departure from reality. Ritz and Einstein argued this issue, along with the issue of the origin of the second law of thermodynamics in 1908-1909, culminating in a joint (1909) paper (RE) in which each author stated his opinion. This joint article was Ritz's last published journal article.)

Ritz says that Lorentz chose to reject the idea of electromagnetic waves converging on a charge by admitting that charged elements are the only points of origin for disturbances.(170)

[Ritz] "...to eliminate the physically impossible solutions [of Maxwell's equations] it only requires adoption a priori of the formulae for retarded potentials, which distinguish the elementary actions as in the classical theories, and to prove that they satisfy the equations is to say that they can replace them completely, whereas the inverse is not the case." (171)

[Ritz] "...it is the formulae of elementary actions, and not the system of partial differential equations, which is the complete and exact expression of Lorentz's theory." (172)

4. - Energy. (172-179)

[Ritz] "..energy can be expressed in the form of an integral extended over all space. ... Maxwell admits...that each element of volume is effectively the seat of a quantity of energy."(172)

"The [Poynting] theorem states itself elegantly in considering the energy as being comprised of an indestructible fluid which moves parallel to the radiant vector."(173)

[Evans] The problem with this picture, as pointed out by Ritz, is that the extended integral throughout space can be defined in an infinite number of ways. The localization of energy is undetermined. Similarly, the flux of energy (the Poynting Theorem) can be modified in an arbitrary way. Ritz summarizes this situation by stating that

[Ritz] "The localization of energy must therefore be attributed to a number of logically useless (and perhaps harmful) conceptions in the Maxwell Lorentz theory."(176,177)

[Evans] This difficulty carries through into the definition of photon in the later quantum theories.

[Ritz] "...as long as we have not introduced the hypothesis of retarded potentials, a continuous portion of the energy, from converging waves coming from infinity, remains just as possible as the lost energy that we observe in reality. If an engine could perpetually draw energy from ether solely, independently of the presence of material bodies, it could have perpetual motion."

[Evans] The most telling criticism by Ritz appears on p. 179.

[Ritz] "In the most general case of electromagnetic radiation, conservation of energy is no longer a law, but a convention."(179)

5. - Gravitation. (179-181)

[Ritz] "We can again say that the condition of stability of a continuous medium, elastic or otherwise, is always such that the energy is minimum when deformation is zero; here, [where the gravitational force is equal to zero] it is maximum; the gravitational field would be in unstable equilibrium at infinity and wherever the force is zero. ... The notion of field doesn't seem applicable to gravitation; it shouldn't therefore be an issue to consider as a general base for the explanation of physical phenomena." ..."On the contrary, the law of elementary action which results from Lorentz's theory, if we replace electric charges by masses, can, as in the similar laws of Weber, Gauss, etc., replace the classical law of gravitation..." (180)

This is mathematics. The nuts and bolts aren't here. In a later article on gravitation (R2) he hypothesized that spinning atomic charges produce gravity through high order residuals of magnetic interactions. (Ritz was proposing spinning charges in 1908. He does mention Lorentz's idea on the subject.

[Ritz] "Zöllner's explanation, adopted by Lorentz, is as we know, that the attraction of two electrical charges of opposite sign, is slightly less than the repulsion of two charges of like sign and of the same absolute value. This explanation destroys the unity of the electric field, and is thus applicable only to elementary actions."(181)

6. - Action and reaction. (181-186)

[Ritz] "With the ether acting on ions without undergoing action itself, [this is related to the superposition principle] Newton's principle [of action and reaction] is not satisfied by Lorentz's theory, ...... can we, from the view-point of the facts, draw from this inequality of action and reaction an objection to Lorentz's theory? The answer is affirmative. (181) .....the inequality of action and reaction constitutes therefore a serious objection to Lorentz's theory." (183)

[Evans] He supports this objection with reference to the experiment, on the pressure of light on material in [the best available] vacuum.(184)

[Ritz] "If we are content with the forces exerted by ions on one another existing without the intervention of an intermediate, such as ether, then the finite speed of propagation leads to the lack of simultaneity and to the inequality of actions of ions on one another when they are separated ...." (185)

[Ritz] "We...use Poincaré's example, the recoil of an artillery piece and the force experienced by a body that transmits a wave of radiant energy in a certain direction are absolutely analogous, which is not the case when, instead of using this model, we consider the energy to be propagated (the ether theory)."(185)

[Evans] About fifty years or more later Jackson ... summarized the way in which this [radiative] recoil was introduced in the [1903-1904] Abraham-Lorentz equation of motion... . it was not present in the original Lorentz theory ... . This is a problematical equation with unphysical runaway solutions. It is not rigorous or fundamental ...

7. - Analogy Between Ether and Elastic Bodies. (186-189)

Ritz is a currently recognized, widely referenced, authority on vibrations in solids.

[Evans] The most serious difficulty of all is that the transversal view of radiation propagating in ether violates the third law of Newton, because this view is based on the Maxwell-Lorentz theory without the reaction corrections of Abraham and Lorentz. ... Ritz describes clearly ... that an ether supporting only transverse propagation is mechanically unstable because it has zero resistance to compression. [He] concludes that such an ether does not exist, and follows Schwarzschild in showing that the Maxwell-Lorentz theory is equivalent in all respects to DELAYED action at a distance. Action and reaction are not equal and instantaneously opposite in the Maxwell-Lorentz theory.

[Evans] Ritz rejects the transversality condition in the pure ether, or vacuum, as early as 1908. ... Nearly ninety years later, this question is still being discussed, despite the fact that there is so much accumulated evidence to show that the transversality condition is a false imposition on a linear, incomplete, theory, Maxwell Lorentz electrodynamics.

8. - Electrodynamic Mass. (189-197)

Ritz's theory employed Galilean relativity and offered a rationale for how the magnitudes of electrodynamic forces could be functions of relative velocities, between force carrying particles and electrical charges rather than masses being relativistically variable.

On Ritz's interpretation of Kaufmann's experiments on magnetic and electrical bending of fast electrons (beta rays):

[Ritz] "...instead of a mass becoming infinite when we approach the speed of light, we would have forces that are annulled because they propagate precisely with the velocity of the mobile electron." (194)

[Ritz] "Kaufmann's experiments can equally be interpreted by modifying the existing laws of Electrodynamics in a manner that eliminates absolute motion and by making the electrodynamic mass constant.(196)

9. - Absolute Motion. (197-205)

[Evans] ... Ritz discusses special relativity. Here, I am less sure that Ritz grasped the full significance of the special theory of relativity, but since that theory was only three years old at the time of writing (1908) this is not surprising. He is reluctant to accept Einstein's 1905 paper, preferring the earlier suggestions by Poincaré and Lorentz.

Evans goes to bat for Einstein's two postulates of relativity and then states:

[Evans] This notwithstanding, the criticisms of the 1905 paper by Melbourne Evans in about 1960 are valid. It is time that the academic physicists considered this analysis. However successful, the logical basics of special relativity are troublesome. Similar problems appear in QED, as described most vividly by Feynman himself. Ritz senses this trouble with special relativity, but in my own opinion he does not give Einstein the credit due to him. Perhaps there was an element of personal rivalry, as is so often the case in real-life physics.

[Evans] Ritz finds the FitzGerald-Lorentz contraction impossible to swallow:

[Ritz] "It is evident that this hypothesis confuses our notions of solids,..." and "Does the assertion of the reality of this contraction have any sense? It results, from the researches of Einstein, to which we return later on, that the answer is negative." [The idea is that the contractions are only observationally apparent.]

[Evans] We are led to expect that Ritz will now regurgitate the Einstein theory without criticism, but he does not. This is either very perceptive or a lack of understanding of Einstein's reasoning, I am not sure which. He accepts the need to eliminate absolute motion as addressed by Lorentz, Poincaré and Einstein, 1903 to 1905:

[Ritz] "If therefore we do not wish to admit that the speed of light depends on that of bodies emitting it, and is purely relative, like all speeds (and the ether concept alone prevents drawing out of the relativity principle this so natural consequence) we will have to modify the definition of time."

[Evans] There is an inherent contradiction in this understanding of the Einstein Principle, the signal velocity c is a universal constant and Lorentz invariant. This at once abolishes and uniquely depends on the ether, according to Ritz. ...

10. - Summary and Conclusions. (205-209)

[Evans] Repeated readings of these characteristically brilliant criticisms by Walter Ritz has led me to conclude that he rejected, at least in part, the notion of in-vacuo electromagnetic transversality. The idea of ether was firmly rejected and with it, the notion of light propagation in a strange elastic medium (light-ether or lichtaether) which supports only transverse waves with no resistance to compression and with unstable mechanical equilibrium.

[Evans]... Ritz leaves open the question of whether the Fresnel diffraction experiments prove transversality or not. ...With this single, but important, reservation I feel that Ritz almost certainly rejected transversality in the vacuum as early as 1908, at a point when the new Lorentz theory was in its relative infancy and by no means widely accepted

Ritz knew that the speed of light aspect of his preliminary hypothesis was not consistent with Fizeau's experiment on the entrainment of waves. It was a result of his insistence on honoring the superposition theorem. (His fictitious particles were not affected in their actions on matter.) He did this to be faithful to Lorentz's model. (It is as though D'Artagnan was fighting with one hand tied behind his back.) He planned a revision, ... but he died in 1909, at age 31, and his work languishes.

Perhaps the time is right for more musketeers.


(E1) Einstein, A., Sidelights on Relativity (1922 translation), p. 11.

(E2) Evans, M., Commentary on Ritz's 1908 electrodynamics article. His commentary, which is pro-Einsteinan in outlook, was prepared as an accompaniment to an English translation of the Ritz article, that is "slated" to appear in the on-line journal Apeiron. [The translation was never submitted, (author had other irons in fire) but Professor Evans kindly gave permission for his comments to be used in this Philadelphia NPA paper. 12 Feb 2005.]

(H1) Hovgaard, W., Ritz's Electrodynamic Theory, Math & Phys, 218, (1931-1932)
[SAO/NASA ADS link added 07 Jun 2017.]

(L1) LORENTZ, H.A., Archives neerl., t. XXV, 1892; Versuch einer Theorie der elektrischen und optischen Erscheninungen in bewegten Körpern, Leiden, 1895; Elektronentheorie: Enzyklopädie der math, Wissenschaften. Bd. V, Heft l, Leipzig, 1904.
[Ref corrected on 04 Dec 2015.]

(R1) Ritz, W., Recherches Critiques Sur L'Electrodynamique Generale; Ann. de Chim. et de Phys3, 145 (1908). For an English translation of this work, see: Critical Researches on General Electrodynamics.

(R2) Ritz, W., La gravitation, Scientia, 10, 2, (1909).

(RE) Ritz, W., and A. Einstein, Phys. Zeits.,10, 323, (1909). For an English translation and commentary on this article, see, Fritzius, R., The Ritz-Einstein Agreement to Disagree, Physics Essays, 3, 371, (1990).
A reprint of this article is on this web site.


For a current Pro Ritz viewpoint I recommend the 1995 "History of Physics" article titled Walter Ritz as a theoretical physicist and his research on the theory of atomic spectra, by M.A. El'yaschevich, N.G. Kembrovskaya, and L.M. Tomil'chik which appeared in Uspekhi Fizicheskikh Nauk, Vol 165, pp. 435-455. The article, in English, touches on 23 of Ritz's 25 publications. In addition to the technical details in the history, the authors make the following statements about Ritz and how his ideas have been handled. Page numbers in parentheses are from their article.

"..his [Ritz's] actual role in the prehistory of theoretical spectroscopy was much more significant than is usually accepted, and the real scale and originality of his personality have not yet been given proper acknowledgement." (p. 435)

"His untimely death was bitterly regretted by such scientists as Rayleigh, Sommerfield and Rozhdestvenskií." (p. 436)

"While describing the scientific work of Ritz, it should be stressed that the modern historiography devoted to him is extremely scanty." (p. 436)

"Analysis of the elastic and magnetic atomic models proposed by Ritz to explain spectral regularities is completely absent; ..." (p. 436)

"Practically no reference is made to Ritz's works in the account of the history of electrodynamics, although they, undoubtedly are worthy of this. The only publication in the world which is specifically devoted to his scientific activity as a whole seems to be an article by the American science historian Forman published in volume 11 of the multi-volume Dictionary of Scientific Biography, edited in 1976 (Charles Schribner, New York). Regretfully, this excellently written and very informative essay is as little known to physicists as the complete works collection itself." (p. 436)

"The astonishing, although now little known, fact remains that Ritz managed to construct mathematical models from which one can logically derive, as natural consequences, analytical expressions for the spectral terms and their differences which not only excellently fitted the experiments, but were also confirmed later on by the quantum theory. " (p. 437)

"...it is necessary to emphasize that one cannot agree with the purely negative assessment of Ritz's studies on electrodynamics which constitute a very significant part of his scientific heritage." (p. 438)

"Usually attention is exclusively fixed on the point of Ritz's general concept which is connected with denying one of the basic postulates of special relativity theory, the principle of the independence of light speed from the source velocity." (p. 438)

"In Ritz's studies on electrodynamics one can clearly distinguish the critical and constructive parts, each of which is worth further historical and methodological analysis." (p. 438)

Paul Forman's biography on Ritz, mentioned above, closes with the opinion that the Michelson-Morley experiment, repeated in 1924 with astronomical light sources, told against Ritz's theory. (For a counter argument see John Fox's article, Evidence Against Emisson Theories, Am. J. Phys., 67, 1 (1965).

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