Theremin

Lev Termen (Leon Theremin) was known for many feats,
From X-ray crystallography to TV making. Neat?
Alas, he was the Bolshevik who made the Great Seal bug,
Unseen by our ambassadors for seven years; oh, ugh.
However, few Americans remember him for much
Except a certain instrument that’s played without a touch.
He’d made a motion sensor and discovered that the sound
It made would change in pitch because he moved his hand around.
He added an antenna to control the volume too.
Across the 1920s, this would help his fame accrue.
He called his work the etherphone, but other folk preferred
A term that’s more eponymous, and that’s the final word.