Polsey telegraph relay
date: label: date made
content: ca 1862
name: label: maker
content: J. Polsey & Co.
notes: label: Description
content: Telegraph relays amplified electrical signals in a telegraph line. Telegraph messages traveled as a series of electrical pulses through a wire from a transmitter to a receiver. Short pulses made a dot, slightly longer pulses a dash. The pulses faded in strength as they traveled through the wire, to the point where the incoming signal was too weak to directly operate a receiving sounder or register. A relay detected a weak signal and used a battery to strengthen the signal so that the receiver would operate.
label: Description
content: This relay was made by John Polsey & Company of Boston, a firm better known for making clocks. Polsey (1816-1873) established the firm about 1859 and closed it in 1864. Western Union Company donated the relay to the Smithsonian in 1904 and reported that the relay was "a relic of the Confederacy and was used at Fort Sumter by W. R. Cathcart, manager for many years of their Columbia, SC office who was stationed at that fort as a military operator."
label: Location
content: Currently not on view
place: label: place made
content: United States: Massachusetts, Boston
setName: label: See more items in
content: Work and Industry: Electricity
label: See more items in
content: Communications
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content: Telegraph Relays & Repeaters
creditLine: label: Credit Line
content: from Western Union Telegraph Company
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: EM.230788
label: catalog number
content: 230788
label: accession number
content: 43225
objectType: label: Object Name
content: telegraph relay
physicalDescription: label: Physical Description
content: marble (overall material)
label: Physical Description
content: metal (overall material)
label: Physical Description
content: plastic (overall material)
label: Measurements
content: overall: 4 in x 10 1/4 in x 5 1/2 in; 10.16 cm x 26.035 cm x 13.97 cm