Morse "Port-rule" telegraph transmitter
date: label: Date made
content: 1837
name: label: maker
content: Morse, Samuel Finley Breese
notes: label: Description (Brief)
content: This is Samuel F. B. Morse’s prototype telegraph transmitter made in 1837. Morse (1791-1872), a painter of modest renown, reinvented himself by becoming an inventor. At age 41, returning from an art sojourn in Europe, Morse conceived of a way to send electric signals over a single wire: the telegraph. With the assistance of machinist Alfred Vail and others, Morse refined his ideas and made this proof-of-concept telegraph transmitter called a port rule. After several years of refinements, Morse and Vail sent the famous message “What Hath God Wrought” over a line between Washington, DC and Baltimore, Maryland. Adopted by news organizations, the military, and railroads, the almost instantaneous nature of telegraphs revolutionized communications and helped create a sense of nationhood. Eventually ordinary people (if they could afford the fee) could send fast messages called telegrams to friends and family anywhere in the country.
label: Description (Brief)
content: The object consists of a wooden base in the center of which is mounted a wooden bracket that supports a wooden lever arm on a pivot. A metal plate is set in one end of the lever arm and a copper wire passes through the other end. A slotted wooded carriage rides on a cloth belt under the lever arm and is moved by a wooden crank on the base. Lead slugs, each cut to represent an alpha-numeric character, are set in the slot. The sender turns the crank so the carriage passed under the lever arm. The metal plate rides along the top of the lead slugs, causing the arm to move up and down. As the arm moves, the copper wire on the other end dips into two small brass cups filled with mercury.
label: Description (Brief)
content: The cups were connected to a battery and to an electromagnet on the receiver. When the wire dipped into the mercury, electricity flowed from the battery to the receiver. When the arm lifted the wires out of the mercury, the electricity stopped flowing. The receiver recorded a wavy line that matched the shape of the lead slugs—the message—on a piece of paper.
setName: label: See more items in
content: Work and Industry: Electricity
label: See more items in
content: Communications
label: Exhibition
content: Inventing In America
label: Exhibition Location
content: National Museum of American History
creditLine: label: Credit Line
content: Gift of the Western Union Telegraph Co.
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: EM.181250.02
label: catalog number
content: 181250.02
label: accession number
content: 31286
objectType: label: Object Name
content: Telegraph Instrument
label: Object Name
content: telegraph transmitter
physicalDescription: label: Measurements
content: overall: 7 1/2 in x 7 in x 36 3/4 in; 19.05 cm x 17.78 cm x 93.345 cm