Patent Model - Improvement in Duplex Telegraph Instruments
Maker and role
Joseph Stearns (b.1831, d.1895), Patentee
Production date
Feb 25 1873
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Object detail
Media/Materials
Walnut (visual), brass, steel
Measurements
9 3/8 x 9 7/8 x 2 1/8" (23.8 x 25.1 x 5.4cm)
Description
Stearns's invention "relates to apparatus for the simultaneous transmission of two signals from opposite ends of the same line-wire; and consists of a key of the peculiar construction..., and of its combination with a magnet or coil excited by the main-line battery, a neutralizing or opposing magnet or coil excited by an equating battery, and a suitable resistance for the purpose of preventing the receiving magnet or relay, though always in the circuit, from being affected by currents transmitted from the home station." (Patent Number 136,274)
Collection
Object number
2015.14.1540a,b
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