Cardboard Disc
notes: label: Description
content: William J. Hammer (1858-1934) began working with Thomas Edison in 1879, assisting in the development of the incandescent light bulb. In time he was known as an electrical engineer and expert on electric power distribution. Other interests included radium, selenium cells, aeronautics, and the transmission of sounds. This cardboard disc is part of his apparatus for measuring light.
label: Description
content: Ref: William J. Hammer, “Method of Measuring Light,” U.S. Patent 333,308 (May 26, 1908).
label: Location
content: Currently not on view
setName: label: See more items in
content: Medicine and Science: Physical Sciences
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: PH.320556.03.04
label: catalog number
content: 320556.03.04
label: accession number
content: 241402
objectType: label: Object Name
content: cardboard disc
physicalDescription: label: Measurements
content: overall: 1/8 in x 24 in; .3175 cm x 60.96 cm