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bridge testing switch
bridge testing switch

bridge testing switch

Datelate 19th-early 20th Century
Inventory Number0283
ClassificationSwitch
Subject
    Cultural Region
      Place of Origin
        Place of Use
          Dimensions7.4 × 27 × 18 cm (2 15/16 × 10 5/8 × 7 1/16 in.)
          Material
            Accessories
            DescriptionSliding contact switch. Double pull, double throw switch (DPDT switch) with heavy contacts. Assorted connecting leads attached. Mounted on rectangular wooden base. Leveling screws missing.
            Signedbase plaque engraved: THE LEEDS AND NORTHRUP CO. / SCIENTIFIC INSTRUMENTS PHILADELPHIA. 7312; another base plaque engraved: HARVARD UNIVERSITY / 465
            Curatorial RemarksLeveling screw missing. Was first incorrectly catalogued as 1997-1-0229, so slide will have that number.
            FunctionUsed to create and break an electrical circuit.
            ProvenanceFrom the Harvard University Engineering School. Removed to this collection November 1956.
            key for resistance bridge
            Leeds & Northrup Company
            Date: mid 20th Century
            Object number: 1998-1-0607
            bridge key with dual key for battery and galvonometer circuits
            Morris E. Leeds & Company
            Date: 1899-1903
            Object number: 0386
            box containing A.C. relays, electrical bells, and timers
            Leach Relay Company
            Date: 1890-1930
            Object number: RS0531
            reversing switch with mercury contacts for bridge work, D.P.D.T.
            American
            Date: late 19th-early 20th Century
            Accessories: tilting arm (0380b)
            Object number: 0380a
            Green wooden storage box containing switches
            Date: 1890-1930
            Object number: RS0486
            mercury contact switch for bridge work, D.P.D.T.
            Date: late 19th-early 20th Century
            Object number: 0379
            Green wooden storage box containing transformers.
            Date: 1900-1930
            Object number: RS0653
            tilting arm with six contacts for reversing switch
            American
            Date: late 19th-early 20th Century
            Accessories: goes with reversing switch (0380a)
            Object number: 0380b
            rotor and brush switch
            Harvard Engineering School
            Date: early 20th Century
            Object number: 0382