Edison Records
Thomas A. Edison invented the phonograph, the first device for recording and playing back sound, in 1877. After patenting the invention and benefiting from the publicity and acclaim it received, Edison and his laboratory turned their attention to the commercial development of electric lighting, playing no further role in the development of the phonograph for nearly a decade. Edison's original phonograph recorded on sheets of tinfoil and was little more than a crude curiosity, although one that fascinated much of the public. These earliest phonographs were sold mainly to entrepreneurs who made a living out of traveling around the country giving "educational" lectures in hired halls or otherwise demonstrating the device to audiences for a fee. The tinfoil phonograph was not fit for any real practical use and public interest soon waned.
Acoustic camera
The term acoustic camera has first appeared at the end of the 19th century: A physiologist, J.R. Ewald, was investigating the function of the inner ear and introduced an analogy with the Chladni plates (a domain nowadays called Cymatics), a device enabling to visually see the modes of vibration of a plate. He called this device an acoustic camera. The term has then been widely used during the 20th century to designate various types of acoustic devices, such as underwater localization systems or active systems used in medicine. It designates nowadays any transducer array used to localize sound sources (the medium is usually the air), especially when coupled with an optical camera.