Bell Demonstrates the Telephone Summary

  • Last updated on November 10, 2022

Alexander Graham Bell’s first public demonstrations of the telephone caused a sensation at Philadelphia’s Centennial Exposition and captured the interest of scientists and inventors throughout the world, launching a new era in communications.

Summary of Event

Alexander Graham Bell’s path to his invention of the telephone began in his early interest in teaching speech to the deaf. He developed that interest as a result of his father’s own work in the area and the influence of his mother, who was hearing-impaired. The elder Bell, like his father before him, devoted himself to the mechanics of sound and is regarded as a pioneer teacher of speech to the deaf. Alexander worked with his father in Edinburgh, Scotland. Inventions;telephone Bell, Alexander Graham Telephone;invention of Watson, Thomas Augustus [kw]Bell Demonstrates the Telephone (June 25, 1876) [kw]Demonstrates the Telephone, Bell (June 25, 1876) [kw]Telephone, Bell Demonstrates the (June 25, 1876) Inventions;telephone Bell, Alexander Graham Telephone;invention of Watson, Thomas Augustus [g]United States;June 25, 1876: Bell Demonstrates the Telephone[4900] [c]Inventions;June 25, 1876: Bell Demonstrates the Telephone[4900] [c]Communications;June 25, 1876: Bell Demonstrates the Telephone[4900] [c]Science and technology;June 25, 1876: Bell Demonstrates the Telephone[4900] Helmholtz, Hermann von Reis, Johann Philipp

After immigrating to the United States, Bell became a teacher at the Boston School for the Deaf and later became a professor of vocal physiology at Boston University. While in Boston, he improved his knowledge of electricity and continued the study he had begun before coming to the United States of the theories of Hermann von Helmholtz Helmholtz, Hermann von , a German physicist concerned with the mechanical production of sound. During the 1850’s, Helmholtz had described the method by which the inner ear responds to differences in pitch and had shown that sound quality as recognized by the human ear is a product of a number of overtones that are developed from rapid vibrations over the original sound source.

Bell’s invention of the telephone stemmed from his conviction that sound-wave vibrations could be converted into electric Electricity;and telephone[Telephone] current, and that at the other end of an electric circuit, the current could be reconverted into identical sound waves. Thus, he believed, it would be possible to establish voice communications that would operate at the speed of light.

Prior to Bell’s effort, Johann Philipp Reis Reis, Johann Philipp , working in Frankfurt, Germany, had developed an apparatus he called a telephone, that could alter an electric current through sound power. His device, which was functioning successfully as a laboratory tool after 1860, reproduced audible sounds but did not transmit speech. His failing, apparently, was in not understanding that vibratory mechanisms were necessary at both the transmitting and receiving ends of a circuit in order to reproduce voices.

In 1874, Bell was able to describe to his father an “electric speaking telephone,” Electricity;and telephone[Telephone] but he was not then convinced that the human voice was strong enough to produce the necessary undulating electric current. However, as a result of experiments done the next year, he was able to give his laboratory assistant, Thomas Augustus Watson, the necessary instructions for building an electromagnetic Electromagnetism transmitter and receiver.

On March 10, 1876, the first voice communication was made by means of impulses transmitted through wires when Bell, as a result of a laboratory accident, called out to his assistant, “Mr. Watson, please come here. I want you.” Watson was on another floor of the building with the receiving apparatus, and distinctly heard this utterance. Bell’s success after many experiments in what he called “telephony” came shortly after he began using a liquid transmitter. This discovery secured for Bell full credit for the development of the telephone. He had received a U.S. patent for his invention only a few days before.

Exhibit of Bell Telephone equipment at the Exposition Universelle in Paris in 1889.

(Library of Congress)

Public demonstrations of the telephone soon followed. The most significant of these took place on June 25, at the Centennial Exposition Centennial Exposition (1876);telephone Philadelphia;Centennial Exposition in Philadelphia. The telephone was hardly a perfect instrument. For one thing, its liquid transmitter delivered only a feeble electric Electricity;and telephone[Telephone] current and made the instrument cumbersome and sensitive to motion. Even so, it was considered the most remarkable of all the exhibits at the 1876 exposition. Bell himself demonstrated the device, to the delight of those present, including the Brazilian emperor, Dom Pedro II Pedro II [p]Pedro II[Pedro 02];and telephone[Telephone] , who exclaimed when he heard Bell’s voice in the receiver: “It talks!” This statement found its way into numerous newspaper headlines, and news of Bell’s invention soon spread throughout the scientific community as well. Back in Boston, Bell and Watson succeeded in holding the first telephone conversation in October of the same year.

Improvements in Bell’s early instrument were soon forthcoming. Perhaps the most important of those made almost immediately was the carbon granule transmitter credited to Thomas Alva Edison Edison, Thomas Alva [p]Edison, Thomas Alva;and telephone[Telephone] . This device transmitted electricity by compressing or expanding the fluctuating air vibrations set up by sound. After Bell began demonstrating the telephone’s ability to carry conversations over telegraph wires, interest in the telephone as a practical means of communication soon increased.

Technical improvements in the telephone led to its commercial development. The first telephone line was installed in 1877. It soon was possible to realize Bell’s 1878 prediction that the day would come when a grand system of connecting lines would be established so that people not only could communicate with one another in the same city but could also communicate over long distances through central receiving and transmitting stations. The direct result of Bell’s foresight was the establishment, within about ten years, of the framework of the twentieth century Bell Telephone system.


Although Bell’s imagination and scientific understanding led him to further innovations in the years following the invention of the telephone, none were to achieve commercial success. Not long after he invented the telephone, he rededicated his energies to his lifelong project of educating the deaf. He began a school for the deaf in Washington, D.C., formed a national society to promote the learning of speech by the hearing-impaired, and was influential in increasing public funding for deaf education in several states. However, the world chiefly remembers Bell for the remarkable device he made when he was only twenty-nine years of age. On the day of his burial in Scotland, in 1922, telephone service was brought to a halt for one minute in the United States in honor of Bell and his contribution to technology.

Further Reading
  • citation-type="booksimple"

    xlink:type="simple">Bruce, Robert B. Bell: Alexander Graham Bell and the Conquest of Solitude. Boston: Little, Brown, 1973. Nearly definitive biography of Bell. Thorough and engaging, it provides a clear, detailed look into the scientific and practical struggles associated with the development of the telephone.
  • citation-type="booksimple"

    xlink:type="simple">Du Moncel, Theodore. The Telephone, the Microphone, and the Phonograph. 1879. Reprint. New York: Arno Press, 1974. Traces the history of the invention of the telephone, with special emphasis on the scientific knowledge involved in its development.
  • citation-type="booksimple"

    xlink:type="simple">Fischer, Claude S. America Calling: A Social History of the Telephone to 1940. Berkeley: University of California Press, 1992. Comprehensive account of the history of the commercial development of the telephone in the United States. Discusses the role of the telephone in changing U.S. social life.
  • citation-type="booksimple"

    xlink:type="simple">Giberti, Bruno. Designing the Centennial: A History of the 1876 International Exhibition in Philadelphia. Lexington: University Press of Kentucky, 2002. Detailed analysis of the Philadelphia exposition at which Bell gave his first public demonstrations of the telephone.
  • citation-type="booksimple"

    xlink:type="simple">Grosvenor, Edwin S., and Morgan Wesson. Alexander Graham Bell: The Life and Times of the Man Who Invented the Telephone. New York: Harry N. Abrams, 1997. Lavishly illustrated biography of Bell that focuses on the early history of the telephone.
  • citation-type="booksimple"

    xlink:type="simple">Mackay, James. Alexander Graham Bell: A Life. New York: John Wiley & Sons, 1997. Mackay depicts Bell as a man of great intelligence and curiosity, and describes his varied interests and inventions. Provides new information about Bell’s early years and how they influenced his later life and work.
  • citation-type="booksimple"

    xlink:type="simple">MacKenzie, Catherine. Alexander Graham Bell: The Man Who Contracted Space. Boston: Houghton Mifflin, 1928. Early biography of Bell, based in part on his own recollections of his struggle to invent the telephone, as told to the author.
  • citation-type="booksimple"

    xlink:type="simple">Ronell, Avital. The Telephone Book: Technology, Schizophrenia, Electric Speech. Lincoln: University of Nebraska Press, 1989. The history and significance of the telephone considered from a variety of perspectives, including philosophy, history, literature, and psychoanalysis. Challenging, but valuable for its efforts to connect Bell’s interest in deaf communications with his interest in the telephone.
  • citation-type="booksimple"

    xlink:type="simple">Watson, Thomas A. Exploring Life. New York: D. Appleton, 1926. This autobiography of Bell’s laboratory assistant provides a vivid account of the invention of the telephone and of the personality of its inventor.

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