Who was first to demonstrate radio waves? The German physicist Heinrich Hertz gets official credit, but the English physicist Oliver Lodge proved Maxwell’s theory at around the same time. Why one became internationally famous practically over night and the other only earned an honorable mention is a fascinating story.
Hertz declined the challenge by Hermann von Helmholtz, the dean of German science, to prove an obscure but crucial aspect of Maxwell’s theory (displacement current). Hertz’s explanation at the time was that he did not know enough about Maxwell’s theory and, in any event, could not think of any relevant experiments.
Then Hertz observed an unexpected but subtle phenomenon while preparing a demonstration for his students. It wasn’t long before he demonstrated radio waves—proving Maxwell’s theory—and discovered the photoelectric effect to boot in the process.
Hertz set out to teach his students about electric induction. (Today, induction is used for purposes such as stepping down 110 volts from a power outlet to 12 volts.) In the school’s laboratory he found a couple of heavy wire coils that terminated in spark gaps and immediately realized they could be used to provide a visual demonstration. A surge of electricity in the first coil would cause it to spark and induce a sufficient current in the second coil to make it spark, too. But when he tried it he was surprised at how easy it was to make the second coil spark. He suspected something other than induction was at work.
He straightened out the first coil but kept the spark gap; in place of the second coil, he used a ring of heavy wire that didn’t quite make a full circle (creating another spark gap). He found he could “induce” a spark in the wire ring even from across the room. As he moved the ring further away, the size of the sparks might increase, then decrease, and then increase again—suggesting he was observing the peaks and nulls of a wave. To better see the sparks, he sometimes placed the ring in a wooden box with a little window. He noticed the sparks were smaller in the darkened box and concluded that light affected the size of the sparks, as well.
After months of experimenting, he knew that he had proved Maxwell’s theory, and published a paper that caused an immediate sensation. Ironically, when asked by newspaper reporters about the waves, Hertz assured them it was just an interesting phenomenon with no practical applications.
Oliver Lodge was also a talented physicist, but he seemed to have a knack for coming up short. He did an experiment that involved discharging a Leyden jar and produced peaks and nulls along a long wire. Satisfied his experiments proved Maxwell’s theory he promptly left on vacation, figuring there would be plenty of time to publish when he got back. He returned to hear the news that Hertz had beat him to the punch. (Later, he realized that the wire only served to guide the waves; it would have been a more dramatic experiment without the wire.)
Lodge also demonstrated wireless signaling before Marconi but neglected to use Morse code. Then Lodge invented a method for dividing the radio spectrum into different frequency channels—what he called “syntony” and we now call "channel surfing." This time he was smart: he patented his invention and eventually sold the rights to Marconi.
Though Lodge did not think it would ever be possible to communicate across the Atlantic Ocean using radio waves, he did believe it is possible to communicate with the dead.
Next time: How Morse and Bell Invented Wire Communications--Setting the Stage for Wireless