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Iron borings coherer (Branly type), 1894
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Iron borings coherer (Branly type), 1894, result 1 of 1

Item Details
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Title
Iron borings coherer (Branly type), 1894
Iron borings coherer (Branly type)
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Work Type
Radio Communication
Date
1894
Location
England
Material
copper (alloy)
glass
wood (unidentified)
Measurements
overall: 50 mm x 260 mm x 65 mm, .26 kg
Description
Iron borings coherer (Branly type), probably made by Oliver Lodge, England, 1894. Mounted on wooden baseboard.
Iron borings coherer (Branly type), probably made by Oliver Lodge, England, 1894. Mounted on wooden baseboard.
The coherer was the first practical device for detecting Hertzian waves. It was devised by French physicist Edouard Branly in about 1890. Branly did not, however, investigate its use for detecting Hertzian waves. Its most familiar form was a tube containing metal filings or turnings loosely packed between metal plugs. This presented a high resistance to current but changed to low resistance in the presence of electric waves because the filings 'cohered' or stuck together. In order to restore the high-resistance state the tube needed to be given a mechanical tap or jolt. This particular coherer was used as a receiver during Lodge s British Association lecture on 14 August 1894, but contrary to some later accounts the signals sent did not form an intelligible message. The electric bell mechanism was used as the vibrator to restore the borings to the high-resistance state.
Repository
Science Museum, Information Age Gallery: Cable
Donated by Mr. Oliver Lodge [Grandson of Sir Oliver Lodge]
Accession Number
Subject
coherer
ID Number
co8005611
Source
Image and original data from Science Museum Group
Rights
The source metadata displayed in the Description field is released under a Creative Commons Attribution 4.0 license.
All other source metadata is released under Creative Commons Zero.
File Properties
File Name
large_1924_0037_0001__0001_.jpg
SSID
26235153

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