At the end of the 19th century several inventors were attempting to record sound photographically. In 1888 the American Alexander Blake photographed a pencil of light from a vibrating mirror, using a glass photographic plate which he kept in motion by means of a clockwork mechanism. Later on a Professor Simon in Germany found that if a DC arc was modulated by sound currents, the original sound could be heard acoustically, whilst at the same time the light intensity varied. He called his invention 'The Talking Arc'.
In 1900, also in Germany, Ernst Ruhmer was able to photograph The Talking Arc on to normal motion picture film, and so became the first person to produce a photographic sound negative. He devised an instrument something like today's sound camera which he called a Photographophon. The camera speed was 10 feet per second, and the sound track extended over the full width of the film. His apparatus was practical and the system worked extremely well with excellent definition on the recording.
Amongst the early inventors one must not forget that intrepid Dutchman called Hedick who, in 1887, discovered that a manometric flame (produced by gas under pressure) could be modulated by sound waves. Image the scene today if his idea had been adopted - "OK, roll for a take"....... (Pass the matches, Fred)!.
JOHN ALDRED