William Du Bois Duddell (1872-1917), British electrical engineer, inventor and instrument maker. His inventions include a thermo-ammeter (measuring the heating effect of AC current), a thermo-galvanometer (a sensitive thermocouple meter). Based on the first electromechanical oscilloscope, invented by the French physicist Andr矇 Blondel, he developed his moving-coil oscillograph for the direct measurement and analysis of the waveforms of alternating currents by photographic recording and observation. Duddell is well known for inventing the ???inging Arc?? He had been tasked with eliminating the unpleasant noises emitted from street lighting by the electric arc lamps. He found that they were caused by current instabilities and that varying the voltage input via a keyboard created musical tones. Duddell produced and demonstrated one of the first electronic musical instruments.