mitted the first wireless telephone message on his newly-invented "photophone." Bell believed the photophone was his most important invention. The device allowed for the transmission of sound on a beam of light. Of the eighteen patents granted in Bell's name alone, and the twelve he shared with his collaborators, four were for the photophone. Bell's photophone worked by projecting voice through an instrument toward a mirror. Vibrations in the voice caused similar vibrations in the mirror. Bell directed sunlight into the mirror, which captured and projected the mirror's vibrations. The vibrations were transformed back into sound at the receiving end of the projection. The photophone functioned similarly to the telephone, except the photophone used light as a means of projecting the information, while the telephone relied on electricity.
Although the photophone was an extremely important invention, it was many years before the significance of Bell's work was fully recognized. Bell's original photophone failed to protect transmissions from outside interferences, such as clouds, that easily disrupted transport. Until the development of modern fiber optics, technology for the secure transport of light inhibited use of Bell's invention. Bell's photophone is recognized as the progenitor of the modern fiber optics that today transport over eight percent of the world's telecommunications.
The Library of Congress has a multitude of information related to Bell's life. Search the following collections:
- Read Bell's correspondence and scientific notebooks. The Alexander Graham Bell Family Papers contains correspondence, scientific notebooks, journals, blueprints, articles, and photographs documenting Bell's invention of the telephone and his involvement in the first telephone company, his family life, his interest in the education of the deaf, and his aeronautical and other scientific research. Use the Time Line to learn more about the inventor or peruse some of the Collection Highlights. To dig deeper into the collection, browse the different series of papers or search on terms of special interest
- Learn more about the inventor. A biography of Bell is featured on the March 10 Today in History. Also, see the feature on the National Geographic Society of which Bell was a founder and first president.
- Search the Today in History Archive on the keywords inventor or invention to find more portraits of creative Americans including Samuel F.B. Morse, Elias Howe, and Henry Ford.
