1) Sound measurement 
The phonomotor or `vocal engine` was a device invented by Thomas Edison in 1878 to measure the mechanical force of sound. It converted sound energy or sound power into rotary motion which could drive a machine such as a small saw or drill. It derived from his work on the telephone and phonograph. ==Operation== Sound waves entering a mouthpiece a.....
• (n.) An instrument in which motion is produced by the vibrations of a sounding body.
Pho`no·mo'tor noun [ Phono- + -motor .] (Physics) An instrument in which motion is produced by the vibrations of a sounding body.