Ruhmkorff electric machine
notes: label: Description (Brief)
content: Appears to be a Ruhmkorff current machine. Painted: "L3A4" and stamped: "W452". Foucault's apparatus for rotation of a copper disc in a magnetic field, 1855. See: Foucault apparatus in: J. Jamin, Cours de Physique de l’École Polytechnique (Paris, 1869), volume 3, page 304. Also in A. Privat Deschanel, Elementary Treatise on Natural Philosophy (New York, 1874), part 2, pages 447-450.
label: Description (Brief)
content: An account of this unit's operation is as follows: “A striking example of the transformation, as it were, of the force of motion into heat is exhibited by an article of apparatus [...] devised by M. Leon Foucault, of Paris. Between the poles of a strong electric-magnet a heavy metallic disc is made to rotate, and although the revolving body does not touch the magnet, yet its motion is stopped by it in a few seconds. The momentum of the disc which is thus overcome gives rise to heat; for the re-action of the magnet produces a current of electricity, and in the resistance to this the heat is generated. A body in motion is in a state of power, and it cannot come to rest without producing some effect on the surrounding matter. The ultimate effect in this case is an agitation of the atoms of the metal.” Joseph Henry, “Terrestrial Physics, and Temperature,” (1857), reprinted in Scientific Writings of Joseph Henry (Washington, 1886), volume 2, page 138.
label: Location
content: Currently not on view
setName: label: See more items in
content: Work and Industry: Electricity
creditLine: label: Credit Line
content: from Columbia University, Department of Physics, thru Alvin P. Tramm
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: EM.322953
label: accession number
content: 249200
label: catalog number
content: 322953
objectType: label: Object Name
content: generator
physicalDescription: label: Measurements
content: overall w/ handle: 15 1/2 in x 14 1/2 in x 14 3/4 in; 39.37 cm x 36.83 cm x 37.465 cm