Earth Inductor or Delzenne Circle
name: label: maker
content: Hawkins & Wale
notes: label: Description
content: Michael Faraday found that the magnetic force of the earth could induce electrical currents in metallic bodies in motion. Building on this idea, Charles Delezenne in France introduced an earth inductor of this sort in 1844.
label: Description
content: This example belonged to the U.S. Military Academy at West Point and dates from the early 1870s. The inscription reads "HAWKINS & WALE MAKERS STEVENS INSTITUTE HOBOKEN, N.J.'
label: Description
content: Ref: Charles Delezenne, "Notions élémentaire sur les phénoménes d'induction," <i>Mémoires de la Societé; des Sciences de Lille</i> 23 (1844): 1-132, on 109-120.
label: Description
content: Adolphe Ganot, <i>Elementary Treatise on Physics</i> (London, 1867), pp. 701-702.
label: Description
content: James W. Queen & Co., <i>Priced and Illustrated Catalogue of Physical Instruments</i> (Philadelphia, 1888), p. 106.
label: Location
content: Currently not on view
place: label: Place Made
content: United States: New Jersey, Hoboken
topic: label: Subject
content: Science & Scientific Instruments
label: Subject
content: Science & Scientific Instruments
setName: label: See more items in
content: Medicine and Science: Physical Sciences
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content: Science & Mathematics
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content: Measuring & Mapping
creditLine: label: Credit Line
content: U.S. Department of Defense, U.S. Military Academy
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: PH.316432
label: accession number
content: 223721
label: catalog number
content: 316432
objectType: label: Object Name
content: earth inductor
physicalDescription: label: Physical Description
content: wood (overall material)
label: Measurements
content: base: 29 in x 29 in; 73.66 cm x 73.66 cm
label: Measurements
content: overall: 27 1/2 in; 69.85 cm
label: Measurements
content: overall: 16 in x 29 in x 29 in; 40.64 cm x 73.66 cm x 73.66 cm