Horophone Type A Crystal Radio Receiver

ca. 1913

Until the development of radio, many business syncronized their clocks and pocket watches with the chimes of the local bell-tower. In 1910 a time-signal service was begun from the Eiffel Tower (the signal was carried as much as 5,200 km at night, half this distance during the day.) The Horophone was designed specifically to receive these signals. Once the signal was received, the operator would set the attached pocket watch to the correct time. Others in the building could then use this "standard" to set their own watches and clocks.