Before the first commercial radio broadcast, when vacuum tubes were large, expensive, and short-lived, Leon Theremin invented the first electronic instrument. Two antennas respond to the position of the hands, one for volume, one for pitch, without the need to touch the antennas. Anyone could make sound from it, and the most difficult thing is to get used to how exquisitely sensitive it is, so that tiny movements make notes of the scale.
The headline above came from a newspaper review after the 1928 Carnegie Hall debut by Leon Theremin himself.
The theremin has experienced a renaissance in the last 10 years. Its sounds can be made more like a human voice than any other instrument. Theremins excel at slow, sentimental melodies in the soprano range
but it's not possible to play quick, exciting music on the theremin because no one can jump the hand with sufficient control.
(This is Carolina Eyck. When she rises an octave for the second time through, all the hand motions have to be half as big as the first time.)