musicmavericks: "The Rhythmicon was a musical keyboard instrument built in 1931 by Leon Theremin at the request of composer/theorist Henry Cowell. Each key of the Rhythmicon played a repeated tone, proportional in pitch and rhythm to the overtone series (the second key played twice as high and twice as fast as the first key. The third key played three times higher and repeated three times faster then the first key, etc.)." Read on
