Inventions That Changed the World
S01E04
S01E0460 min· aired 2/6/2004

The Telephone

TMDb0.0
Nexus es445404TMDb ep 393605TVDb ep 118862

Overview

At the time of Alexander Graham Bell and Thomas Watson's first successful telephone transmission in 1875, the only wires strong enough to be strung over long distances were made of iron. Iron wires had been used for telegraph systems but they were unsuitable for long-distance telephone links. But, in 1877, an American, Thomas Doolittle, developed a method of manufacturing copper wires strong enough to be strung between telegraph poles. Copper's superior conductivity preserved the integrity of the telephone signal to an extent that iron could not. The age of mass communications was born.