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Description: | Siemen's Relay for operating a local device such as a bell that takes a substantial amount of current from the weak current received down a telegraph line. Nos 221 on mahogany base.
"Siemen's Polarised Telegraphic Relay When one of the early nineteenth century pioneers of the telegraph approached the Admiralty for support, he was told that 'telegraphs of any kind were wholly unnecessary'. Even when the superior instruments of Wheatstone and Cooke were developed, few investors with money and foresight were forthcoming. The arrest of the murderer John Tawell in London changed the public perception of telegraphy. Tawell had been seen boarding a train at Slough and his description telegraphed ahead of him to Paddington Station. That was around the year 1845. Within thirty years, the telegraph could rival the steam engine as an invention that had profoundly influenced society. Speed and distance were the telegraph's assets. However, the longer the wire, the weaker the signal. When it arrived, the signal could be too feeble to activate a normal receiver. An early development to overcome this difficulty was the relay, a sensitive electromagnet that could respond quickly to weak signals and, in doing so, close an attached switch. The switch controlled a local circuit with a battery powerful enough to operate a bell, or a morse receiver or, indeed, to re-transmit the signal down many more miles of wire. Our relay was made in the 1880's by the notable but short-lived partnership of Muirhead, Warden & Clark. It looks and feels more like the product of the clockmaker's craft than a key component of the communications industry."
Author: Reid,John.S Date: 1994 Purpose: University.Newsletter | License: | http://www.abdn.ac.uk/historic/Copyright_terms_conditions.shtml | Publisher: | ABDNP University of Aberdeen, Natural Philosophy Collection of Historical Scientific Instruments | Rights holder: | 47718 | Temporal: | 1870-1889 | Source: | University of Aberdeen | Creator: | Warden, Muirhead & Clark, Westminster | Identifier: | http://calms.abdn.ac.uk/Geology/dserve.e... | Go to resource |
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