Hi Suhas,

my impression (only gained from the literature) is that Hertz's contact (by correspondence) with the Maxwellians started only after his crucial findings (generation, detection, reflection, refraction of EM waves).  For some time, Hertz worked (partly on his doctoral dissertation) in Berlin under Helmholtz, who was a kind of "father figure" for German physicists, and around this time Helmholtz declared a certain task officially as a problem of foremost importance in the domain of experimental physics.  I seem to remember that the subject had something to do with EM wave propagation in dielectrics, and that one purpose was to decide between Maxwell's field theory and Weber's action-at-a-distance theory.

Hertz was certainly studious and ambitious enough to be enchanted by the possibility of solving this officially announced task by his former superior Helmholtz. So I think the direction of his work was set by Helmholtz some years before the success.  But Hertz went from Berlin first to the university of Kiel where he seemingly had neither time nor means to work experimentally.  Circumstances changed favorably with his move to Karlsruhe. He stayed in contact with Helmholtz all the time.

The question remains how far Hertz's ideas for his experimental setup were based on the work of others.  I'm pretty sure that his way of detecting EM waves by microscopic sparks in a resonant circuit was his own idea.  Also regarding his transmitter, I feel that he employed resonance more purposeful than anyone before him.

I think I read somewhere that one of the Maxwellians started to pursue an idea for an experimental setup which might have led to something similar to Hertz's apparatus but before having implemented anything he read about Hertz' success.

From another angle, I think the transmitting dipole was in Hertz's view (similar to modern understanding) the source of the radiated fields while the Maxwellians, at least at the outset, held that in every case the fields were primary, and the processes in conductors and dielectrics secondary.

So, I agree that the Maxwellians did NOT significantly influence Hertz while Maxwell's theory did so profoundly, of course.

The question remains how far Hertz's ideas for his experimental setup were based on the work of others. Hmmm...

Hello Suhas,

I didn't mean "... remains to this day" but "... remains in the course of my writing", and the next two sentences were meant to answer this question, at least partly. Certainly, electromagnetic phenomena caused by sparks were known before Hertz's experiments, but I think that his receiver was crucial to his findings, and I would be surprised to learn that someone else before him had built or suggested anything similar.

I believe it was Hertz who discovered EM waves. Maxwell was always silent about EM waves generation and detection. Maxwell’s ideas and equations were expanded, modified, and made understandable by the efforts of Hertz, FitzGerald, Lodge, and Heaviside. The last three are being referred to as the “Maxwellians.” "Certainly, electromagnetic phenomena caused by sparks were known before Hertz's experiments". Maybe that is why Hertz is kept apart from the "Maxwellians"!

Electron discovery came much later after Maxwell's death. Maxwell concluded dimensionally that light was EM in nature. Maxwell coudn't solve the 20 equations as he didn't have the proper boundary conditions. 

It took 20 years for the reduction of 20 equations of Maxwell by Oliver Heaviside and Heinrich Hertz to the 4 scalar and vector equations that we use today! 

Even Kirchoff's job of nodal and loop theorems were completed by Maxwell. 

In 1871, Maxwell showed how a circuit containing both capacitance and inductance would respond when connected to generators containing alternating currents of different frequencies. Maxwell thus developed the phenomenon of electrical resonance in parallel to acoustic resonance first presented by Sir John William Strutt, Lord Rayleigh. Maxwell provided a simpler mathematical expression for the wave velocity and group velocity than what was described by Rayleigh.

Maxwell developed a coherent set of units of measurement of electricity and magnetism in 1863. They were later adopted almost unchanged as the first internationally accepted system of units, which became known misleadingly as the Gaussian system, which is a combination of the electrostatic units and the electromagnetic units. Maxwell also introduced the M, L, and T notation in dimensional analysis in physics which is used currently, and yet nobody wonders who first thought about it. He also produced the first standard of electrical resistance in 1868

Hi Suhas,

could you please tell the title of Maxwell's publication on resonance? I searched the contents of Niven's "The Scientific Papers of James Clerk Maxwell" but somehow missed it.

Maybe the fact that someone outside the circle of Maxwellians proved the existence of EM waves can be looked at as an example of the dialectical "thesis, antithesis, synthesis"-sequence, and the almost always present overshooting of the antithesis:  The thesis was Weber's theory proclaiming action-at-a-distance (consider the "electrified" bodies only).  The antithesis was Faraday's notion of fields, brought into mathematical form by Maxwell.  The overshooting was the Maxwellians' view "Consider exclusively the fields".  The first step of synthesis was Helmholtz's approach to unite Weber's and Maxwell's theories by a set of equations containing one variable (not representing any physical quantity) whose value determines whether the equations act Weber-wise or Maxwell-wise. (I have to admit that I never concerned myself with these equations, and in hindsight they are of no further consequence.)  Hertz, as Helmholtz's pupil, lived in both Weber's and Maxwell's worlds, and was thus able to contribute the second (and arguably greatest) step of the synthesis, the third step being the discovery of electrons (resp. charged elementary particles in general), the fourth Lorentz's microscopic electrodynamics.

"Synthesis" in this context means of course not that we have a mixed Weber-Maxwell theory today but the view that charges and currents are not just epiphenomena of fields but real things, even coupled to matter.

Sir @Joerg Fricke,

I believe it is: on a paper by John William Strutt on the theory of resonance 13 January 1871.

Harman PH (2002b) The Scientific Letters and Papers of James Clerk Maxwell, vol II. Cambridge

University Press (1862–1873), London

On Progressive waves: Harman PH (2002c) The Scientific Letters and Papers of James Clerk Maxwell, vol III. Cambridge

University Press (1874–1879), London

Sorry for the late reply!

Hello Suhas,

many thanks for this reference, and especially for steering my attention to this collection edited by Harman! Somehow, I missed it up till now, and it seems to be a rich source of information.

You are welcome sir!

Hello Suhas Dinesh and Joerg Fricke ,

I should like to point out that David Edward Hughes actually transmitted and received radio waves before Heinrich Hertz and that his detector, a self-restoring coherer, was far superior to Hertz's spark gaps in terms of both sensitivity and ease of use, see my 1993 Thesis "Coherers, a review" on RG, see in particular pp. 12-18. It should be noted that early books on the history of radio acknowledged Hughes as the first person to transmit and receive radio waves, but later books simply obliterated all mention of Hughes' work. For a more recent book on Hughes and his many accomplishments, see the following:

Ivor Hughes, David Ellis Evans; Before We Went Wireless, David Edwards Hughes FRS, His Life, Inventions and Discoveries; Images from the Past; 2011.

Regards,

Tom Cuff

Hello, Thomas Cuff ,

thanks for this hint! Your thesis seems to make an interesting read, I'm already well beyond page 18. :-)

I didn't know that there are monostable coherers. I guess Hertz' receiving dipol with attached spark gap had at least one advantage compared to coherers: One can detect the orientation of linearly polarized waves. Or is this possible with coherers, too?

According to your thesis, several people observed phenomena based on electromagnetic radiation before Hertz and even before Maxwell's equations were published (Henry 1842) but (understandably) had no clue how to reconcile the observation with theory (Hughes even gave in to Stokes.). Hertz, on the contrary, advanced from theory to experiment, had his share of luck, too, but could explain well what was going on.

I don't know if Hertz knew about coherers but even if he did his decision in favor of a dipol with spark gap as receiver seems logical to me. Certainly, he had a publication in mind from the outset, and something like "nobody understands the working principle of coherers but I used one to prove the propagation of radiation" wouldn't sound too convincingly.

Thank you for the reference to the book on Hughes, too. I'm looking forward to reading it.

All the best, Joerg

Hello Joerg Fricke ,

Thank you for your kind words about my thesis. I hope you enjoy reading it as much as I enjoyed writing it.

Re your question about using the coherer to detect the orientation of linearly polarized RF radiation. The answer is maybe and yes. The coherer used by Marconi, for example, was simply a detector and required an external antenna and Earth connection. With the proper antenna, it might have worked to detect the direction of polarization, but Marconi was using a much lower RF carrier frequency than Hertz and Hertz also used LOS (Line of Sight) experiments. However, modern versions of the coherer, MOM (Metal-Oxide-MOM), or more non-judgementally MIM (Metal-Insulator-Metal), 'diodes', which can be thought of as a single mechanical contact coherer, are used for laser heterodyning. And these catwhisker type devices, where the detector and antenna (metal post and springy catwhisker) are so integral to one another and the wavelength of the impinging electromagnetic radiation is so short, hundreds or thousands of nanometers, can be used to detect the orientation of linearly polarized waves, see "Appendix A - MOM Devices" of the thesis.

Hertz had the advantage that he understood and, more importantly, believed Maxwell's mathematics and the conclusions drawn from these same mathematics. People forget that contemporaries of Maxwell did not necessariy sing his praises. It was not until Oliver Heaviside made Maxwell's notation more user friendly that Maxwell's idea really gained eventual acceptance, though, again, it was not universal. Consider Newton and calculus. Today no one uses Newton's notation, we all use the notation of Leibniz. And vector analysis and calculus owes it widespread use due to the user friendly notation of J. W. Gibbs. Remember what the playwright Oscar Wilde said: style is what you wear, fashion is what everyone else wears. And certainly Leibniz, Heaviside, and Gibbs had style, we are just fashion fanboys and fangirls.

Regards,

Tom