|Leon in action
The instrument would come to be known as the Theremin.
Theremin invented the contraption in St. Petersburg shortly after the Russian revolution. It consisted of a small wooden cabinet which contained glass tube oscillators and two antennae that produced electromagnetic fields. In 1922 Theremin demonstrated his instrument in the Kremlin for Lenin, who reportedly was pretty darned impressed.
Lenin sent him on tour in Russia to show off Theremin and his Theremin as an example of Russian progress and ingenuity.
In 1927, Theremin traveled to the U.S., where he played Carnegie Hall and licensed RCA to build his instruments.
But the BBC article said the real reason he came to the U.S. was to engage in industrial espionage. "He had special access to firms like RCA, GE, Westinghouse, aviation companies and so on, and shared his latest technical know how with representatives from these companies to get them to open up to him about their latest discoveries," Theremin biographer Albert Glinsky told the BBC.
Here is a video of Theremin demonstrating his instrument in 1954,
The Theremin was praised by composers like Edgard Varese (he demonstrated one at a lecture at the University of New Mexico in Albuquerque in 1936 according an article in Theremin.info. But it didn't really catch on in American pop culture until the '40s and '50s in movie soundtracks like the ones below.
Hungarian composer Miklos Rozsa used a Theremin in Alfred Hitchcock's Spellbound as well as this 1945 noir classic.
Here's a contemporary Theremin artist, Dorit Chrysler.
The Beach Boys brought the Theremin to rock 'n' roll with "Good Vibrations" in 1966. But the rocker who seems to to have the most fun with a Theremin is Jon Spencer, who usually does a Theremin number in his shows with The Jon Spencer Blues Explosion. This is a strange clip from some even stranger TV I just found.