Center For Integrating Research and Learning

Education Home > MagLab U > Museum of Electricity & Magnetism

ArrowMorse Telegraph

The early 1800s marked a time of rapid discovery in the fields of electricity and magnetism. Before long, inventors were actively seeking ways to harness the new knowledge for practical purposes. In 1831, American Joseph Henry demonstrated to his classes at the Albany Academy in New York an electromagnetic means of communication. Known for developing incredibly strong electromagnets, Henry used a battery linked to an electromagnet by a mile of copper wire to ring a bell. In 1832, after accepting a professorship at the College of New Jersey (later Princeton University), he relayed messages from his laboratory to his home via this early form of the telegraph.

Morse Telegraph

It would fall to another man, however, to commercialize the telegraph and help introduce it to other people around America. Samuel Morse, a professor at New York University, developed a form of the telegraph in the 1830s that used an electric current to move an electromagnet attached to a marker that left a written code on a piece of paper. The recipient could then decipher the code. In 1836, Morse improved the device so that the code was embossed on the paper, rather than written. Later versions rendered the code not visually, but audibly. A transmitter sent an electric current through a wire, which at the receiving end flowed through an electromagnet. This created a magnetic field that caused the receiver’s metal key to be attracted to an underlying plate, resulting in a sound.

The code Morse used was of his own design. Dubbed “Morse code,” the system consisted of various combinations of dots, dashes and spaces to represent letters, numbers and punctuation. To produce a dot or dash, the sender pressed down on a simple key made of steel, hitting a metal plate beneath it. The contact completed an electric circuit, producing a pulse of electricity that traveled from the transmitter down a telegraph wire to the receiver. The amount of time the sender held down the key determined whether a dot or dash was received at the other end (a dash being equivalent to about three dots). Spaces occurred whenever the key was raised and the electric circuit broken. The length of a space signaled whether the code that followed was part of the same symbol or marked the beginning of a new symbol or word in the message.

Morse gave a public demonstration of the telegraph in 1838. But despite the tremendous potential of his invention, he struggled to find financial backers with the kind of money needed to build a working line across a long distance. Finally, after five years, Congress granted Morse $30,000 to build a trial telegraph line between Washington, DC, and Baltimore, Maryland. The line made its debut before it was even finished, on the occasion of the 1844 national convention of the Whig party in Baltimore. A party member carried to Annapolis Junction (between Baltimore and Washington) the news that Henry Clay was their nominee for president. From there, Morse’s partner, Alfred Vail, sent the message the rest of the way by telegraph wire.

A few weeks later, the line was complete. For the official opening, Morse allowed a family friend to select the first message to be sent. She chose a verse from the Bible, “What hath God wrought!” On May 24, 1844, Morse sent that verse in Morse code from the Capitol to Vail, who was at the receiving end in Baltimore. As they say, the rest is history. The telegraph soon proved a tremendous success. Morse received funds to extend his line to additional cities, and telegraph companies began popping up across the country. Western Union, which became one of the largest, opened for business in 1851. Ten years later, their lines stretched from coast to coast, chiefly alongside railways, which were expanding at about the same time. In 1861, engineers built the first transcontinental telegraph line, and by the end of the century the telegraph connected much of the developed world. Some modifications of Morse code were required to accommodate different languages, but it proved adaptable.

Related Electricity & Magnetism Pages


© 1995–2014 National High Magnetic Field Laboratory • 1800 E. Paul Dirac Drive, Tallahassee, FL 32310–3706 • Phone: (850) 644–0311 • Email: Webmaster

NSF and State of Florida logos NSF logo State of Florida logo


Site Map   |   Comments & Questions   |   Privacy Policy   |   Copyright   |   This site uses Google Analytics (Google Privacy Policy)
Funded by the National Science Foundation and the State of Florida