Aquatic telephones let skin divers talk under water (Dec, 1957)
Aquatic telephones let skin divers talk under water
This swimmie-talkie uses water as a medium for sending high-frequency sound waves, on the principle of the hydrophone employed in the early 1900′s for communicating between ships, and in World War I for detecting submarines. Being adjusted here on a frogman, the Aquavox includes a face-mask mike, transducer (on belt, left), transceiver (right), earphones (on thigh). Cotton Associates, Philadelphia, developed it.