Schneider telegraph relay

Description
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.
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.”
Location
Currently not on view
Object Name
relay
telegraph relay
date made
ca 1845
maker
Schneider, Louis Henry
Vail, Alfred
Physical Description
brass (overall material)
iron (overall material)
ivory (overall material)
Measurements
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
iron ring: 1/2 in x 2 1/4 in; 1.27 cm x 5.715 cm
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
ID Number
EM*237666
catalog number
237666
accession number
45161
subject
Communications
Telegraph Relays & Repeaters
See more items in
Work and Industry: Electricity
Telegraph Relays & Repeaters
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
from James Johnson Clark
Additional Media

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