Schneider telegraph relay
date: label: date made
content: ca 1845
name: label: maker
content: Schneider, Louis Henry
label: maker
content: Vail, Alfred
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: These parts are remnants of a very early telegraph relay. An old museum label (probably written by curator George C. Maynard around 1900) reads: "Parts of a telegraph relay. The three pieces are: A base with trunnions supporting the circular armature (the part attracted by the magnets), an iron ring which originally had four electro-magnets supported through the holes, and a frame which includes the contacts and the armature adjusting spring. These were made by L. H. Schneider, of Washington, D.C., shortly after the Morse telegraph was introduced (1844), and was evidently to the order of Alfred Vail, Morse's associate, as the base is stamped with both Schneider's and Vail's names." Maynard reported that, “Dr. Clark says he thinks this instrument was made not long after the Morse telegraph was introduced (1844), and he thinks it was devised by Alfred Vail as it is characteristic of Vail's plans which always demanded heavy apparatus.”
label: Location
content: Currently not on view
setName: label: See more items in
content: Work and Industry: Electricity
label: See more items in
content: Communications
label: See more items in
content: Telegraph Relays & Repeaters
creditLine: label: Credit Line
content: from James Johnson Clark
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: EM.237666
label: catalog number
content: 237666
label: accession number
content: 45161
objectType: label: Object Name
content: relay
label: Object Name
content: telegraph relay
physicalDescription: label: Physical Description
content: brass (overall material)
label: Physical Description
content: iron (overall material)
label: Physical Description
content: ivory (overall material)
label: Measurements
content: base: 1 1/4 in x 4 1/2 in x 4 1/2 in; 3.175 cm x 11.43 cm x 11.43 cm
label: Measurements
content: iron ring: 1/2 in x 2 1/4 in; 1.27 cm x 5.715 cm
label: Measurements
content: frame: 2 1/2 in x 2 5/8 in x 2 1/4 in; 6.35 cm x 6.6675 cm x 5.715 cm