David Edward Hughes FRS (1831-1900), British-born American inventor, experimental physicist and electrical engineer. From his interest in the new electric telegraph he invented a much-improved type-printing machine. It was commercially successful and widely adopted internationally. He is credited with the invention of the carbon microphone in 1878, the first practical working microphone that enabled proper voice telephony. A year later he invented the induction balance (later used in metal detectors). He observed and recorded experiments where sparks from a telephone receiver emitted signals that affected a nearby induction balance. He had unknowingly come across the phenomenon of radio waves nine years before Heinrich Hertz proved their existence in 1888 and sixteen years before Marconi's wireless telegraphy.