The German Genius

accompanied by the rise to prominence of the idea of a universal ether as a “quasi-hypothetical,” continuous, and all-pervading medium through which forces were propagated at a finite speed. 4 This helped people consider the possibility that the foundation of these forces was electromagnetic rather than mechanical. In this environment, new ideas began to proliferate—rudimentary notions of antimatter, for example, of extra dimensions, most important a new field of “energetics,” put forward by the German physicist Georg Helm and his chemist colleague Ludwig Ostwald. In this view, energy, not matter, was the essence “of a reality that could be understood only as processes of actions.” Energetics turned out to be important in that, although turn-of-the-century physics revolved around the two “upheavals” mentioned earlier, the first German name to shine was in a different but related field, where the “ether,” electromagnetism, and, by implication, energy, were also important elements.
    Heinrich Rudolf Hertz was born in Hamburg in 1857, the son of a Jewish lawyer who had converted to Christianity. Heinrich was a clever linguist, learning Arabic and Sanskrit but he also had a liking for the natural sciences and a facility for building experimental equipment, particularly in physics. He went to the university in Munich and afterward in Berlin where he studied under Gustav Kirchoff and Hermann von Helmholtz and also attended Treitschke’s lectures. 5 His PhD dissertation in 1880 was so well received that he became Helmholtz’s assistant, after which he was appointed a lecturer in theoretical physics at Kiel. Though distinguished enough as a university, Kiel was not very big and, unlike other institutions, had hardly any laboratory space—this was why theoretical physics flourished there, a relatively new discipline, as we have seen, in which Germany led the way. At Kiel, Hertz produced his first important contribution when he derived Maxwell’s equations but in a way that was different from Maxwell’s own and did not involve the assumption of an ether. 6 On the strength of this, Hertz was appointed the following year at the age of twenty-eight to the chair of physics at Karlsruhe, a much bigger, better-equipped university. There his first significant discovery was of the photoelectric effect, whereby ultraviolet radiation releases electrons from the surface of a metal (Einstein’s explanation of the photoelectric effect, not his work on relativity, won him the Nobel Prize—see below). Hertz was becoming the theoretical physicist par excellence.
    With his gift for manufacturing laboratory equipment, in 1888 he produced his most innovative device yet. The central element here was a metal rod in the shape of a hoop with a minute (3mm) gap at midpoint (not unlike a large key-ring). 7 When a sufficiently strong current was passed through the hoop, sparks were generated across the gap (he darkened the room to facilitate observation). 8 At the same time violent oscillations were set up in the rod forming the hoop. Hertz’s crucial observation was that these oscillations sent out waves through the nearby air, a phenomenon he was able to prove because a similar circuit some way off could detect them. In later experiments Hertz showed that these waves could be reflected and refracted—like light waves—and that they traveled at the speed of light but had much longer wavelengths than light. Later still, he observed that a concave reflector could focus the waves and that they passed unchanged through non-conducting substances. These were originally called Hertzian waves, and their initial importance lay in the fact that they confirmed Maxwell’s prediction that electromagnetic waves could exist in more than one form—light. Later they were called radio.
    Asked by a student what use might be made of his discovery, Hertz famously replied, “It’s of no use whatsoever. This is just an experiment that proves Maestro Maxwell was right—we just have these mysterious electromagnetic waves that we cannot see with the naked eye.” Asked, “So what’s next?” he answered, “Nothing, I guess.” A young Italian, on holiday in the Alps, read Hertz’s article about his discovery and immediately wondered whether the waves set off by Hertz’s spark oscillator might be used for signaling. Guglielmo Marconi rushed back home to see whether his idea might work. 9 Had Hertz lived (he died from bone disease at