Bell’s Photophone

On June 3, 1880, Alexander Graham Bell transmitted the first wireless telephone message on his newly invented photophone from the top of the Franklin School in Washington, D.C.

Alexander Graham Bell. Timoléon Lobrichon, artist; photograph of 1882 painting. [between 1882 and 1960]. Gilbert H. Grosvenor Collection of Alexander Graham Bell photographs. Prints & Photographs Division
Franklin School, Wash., D.C.. Frances Benjamin Johnston, photographer, [ca. 1900]. Johnston (Frances Benjamin) Collection. Prints & Photographs Division

Bell believed that the photophone was his most important invention. The device allowed the transmission of sound on a beam of light. Of the eighteen patents granted in Bell’s name alone, and the twelve that he shared with his collaborators, four were for the photophone.

Bell’s photophone worked by projecting the 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 that the photophone used light as a means of projecting the information and 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 modern fiber optics.

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  • The Alexander Graham Bell Family Papers contain correspondence, scientific notebooks, journals, blueprints, speeches, 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 Timeline 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.
  • Follow the excitement of new developments in science and technology through articles found in the Library’s database of historic American newspapers, Chronicling America. Invention of the Telephone: Topics in Chronicling America highlights important dates and sample articles related to Bell’s invention.
  • The collection Making of AmericaExternal contains numerous articles about Alexander Graham Bell. News of his most recent inventions was certain to be documented in the scientific and technical literature of the time such as Manufacturer and BuilderExternal.
  • The Library’s pictorial collections contain over one million images; Alexander Graham Bell’s family life and work is extensively documented.
  • 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 Today in History on the keywords inventor or invention to find more portraits of creative Americans including Samuel F. B. Morse, Elias Howe, and Henry Ford.

Battle of Cold Harbor

On June 3, 1864, the second battle of Cold Harbor began. After securing a costly victory at the Battle of Spotsylvania Court House, Union General Ulysses S. Grant encountered Confederate troops as he made his way to Richmond. The Confederates, under command of General Robert E. Lee, were entrenched behind earthworks at Cold Harbor, a crossroads ten miles northeast of the Confederate capital. Over the course of the next nine days, the Union lost 7,000 men while the Confederates suffered 1,500 casualties. Grant moved on toward Petersburg and began the last major siege of the war. Confederate forces finally abandoned Petersburg and Richmond on April 2, 1865.

Cold Harbor, Va. Gen. Burnside and his staff at 9th Corps headquarters. Engraving from a photograph by Mathew Brady; illus. from Harper’s weekly, July 23, 1864, p. 469. Civil War Glass Negatives and Related Prints. Prints & Photographs Division

The first battle of Cold Harbor, also called the battle of Gaines’ Mill, took place on June 27, 1862. It was part of the Seven Days’ Battles (June 25-July 1) that ended General George McClellan’s Peninsular Campaign — an early attempt to capture the Confederate capital.

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