Details

Material referring to the development of the microphone by Professor Hughes, including reports of his early experiments and his links with European developments in the same field. This was later used as evidence to support his case against Edison that he had developed the microphone independently from Edison, and that Preece had not broken Edison's confidentiality, and much of the correspondence relates to Hughes' efforts to clear both his and Preece's name. There are also some reports of experiments which Hughes conducted on telegraph wire for Preece.