Microphonic air gap motion picture

Verso: "Showing bead of moisture ans metaliic dust drawn together by the capillary action of contact space. Width of gap about 1/4000". It was transmitting sound very strong, during and after taking of picture.
Roy M. Allen, Bloomfield, N.J., Photomicrograph, subject:Microphonic Air Gap. No. C-88, magnification 460x." Originally housed in envelop labeled: "Roy M. Allen 1926."

Emile Berliner 1851 – 1929 was a German-born American inventor and businessman. He is best known for his development of the flat disc record and the Gramophone. Berliner worked in the telegraph industry experimenting with sound recording and reproduction. He also developed a new type of phonograph, called the Gramophone. The flat disc records made of hard rubber were easy to produce, and the Gramophone was more durable and easier to use than earlier phonographs. These helped popularize recorded music. Berliner has been credited with developing the first microphone and the first telephone answering machine. His Berliner Gram-o-phone Company in 1895 later evolved into the Victor Talking Machine Company.