Metre Bridge
“The Metre Bridge is employed - a piece of apparatus which is illustrated [here]. It consists of a wooden base, upon the upper face of which is mounted a metallic rectangle; three sides of this rectangle are formed by a broad substantial copper band - having a negligible resistance - and the fourth consists of a platinum silver wire w w joining the copper blocks P and p. This wire is exactly one meter long, and over it slides a key K, which when depressed makes contact by means of a platinum knife-edge with the wire; the exact point on the wire at which this contact is made is indicated by an arrow-head on the key, which slides against a scale, as shown.” (Britannica, 1891)
Source
Benson John Lossing, ed. The New Popular Educator (London, England: Cassell & Company Limited, 1891)
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