Paradigm Lost: Nikola Tesla's True Wireless Page 17

by this impedance, we might think we have obtained the current on the earth.

But what voltage are we to use? Because the antenna illuminates the earth with an electromagnetic wave, the concept of voltage difference or potential difference cannot be applied. It was known in the late 19^th century that electric potential difference between two points is calculated by the line integral of the electric field along a path between those points. When there is a time-varying electromagnetic field between these points the result will depend on the path taken and so the concept of voltage difference ceases to be of use.⁴⁸

Note that Tesla skirts entirely the phenomenon of airplane-to-airplane wireless communication, which had been observed during the war.⁴⁹ Such communication could not possibly involve earth currents if the transmission took place over a desert or dry sandy soil.

The Hertzian Wave Discourse

The publication of Maxwell’s Treatise on Electricity and Magnetism in 1873, which described his work of the previous decade, together with Hertz’s experiments of 1886–9, created the paradigm shift which Tesla was unable to accept. We might be a little indulgent here — the new paradigm was slow to be accepted — consider Marconi for example.

By the late 19^th century Marconi was being lionized in the British press because of his demonstrations of wireless telegraphy, but an interview in McClure’s magazine from 1899 has him declining to say what sort of waves he was using: “What kind of waves they were Marconi did not pretend to say; it was enough for him that they did their business well.”⁵⁰ When asked about the difference between his waves and those used by Hertz he replied “I don’t know. I am not a scientist, but I doubt if any scientist can tell you…”⁵¹ What seemed to impede the connection of Marconi’s waves to those of Hertz’s was that it was known by 1897 that the former’s radiation could pass through the walls of a building while Hertz’s, which was based on a model of radiation as visible light, would apparently not perform such a feat.⁵²

Marconi’s first British patent, number 12039, which was filed in 1896, speaks of an arrangement that he calls “a Hertz radiator” producing effects “which propagate through space [as] Hertzian rays.” But he also talks of electrical actions or manifestations “…transmitted through the air, earth, or water by means of electrical oscillations of high frequency.” For a while, Marconi’s manifestations in the ether were known in some circles as Marconi waves, but the term soon died. Some further indication of the confusion, circa 1900, is a question raised by the historian of early wireless, J. J. Fahie, in his publication of 1901, “… is the Marconi effect under all circumstances truly Hertzian…?”⁵³

After 1899, we find that Marconi began to refer more frequently in his work to “Hertzian waves.” In a speech given before the Institution of Electrical Engineers (now the IET) in