Photoelectric Computing Device, Gibson Graph Comparator
date: label: date made
content: ca 1950
name: label: maker
content: Gibson, Gordon D.
notes: label: Description
content: The search for a rapid mechanical method of assessing the similarity between two time series, and particularly for matching pairs of tree ring width measurements, led Gordon D. Gibson of the University of Chicago to construct this photoelectric instrument in 1949. The lid and base are of wood, with metal hinges and handles, locks on both sides, and a key. The comparator is aluminum with black finish on its face. The sloping front panel has on its left side a metal toggle switch and twelve plastic-topped switches labeled 11 and then 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, and 11. Also on the left is a round light and a push button switch. The center has a glass opening to show the scale on the galvanometer inside. A metal lever is under this. Six square plastic dials and a round dial are on the right side of the front face. A rectangular box protrudes from the back of the instrument. Eleven knobs along the back of the box that connect to eleven glass lamps inside. The inside of the entire instrument is partitioned, so that light from one lamp shines on a particular segment of the front of the machine.
label: Description
content: On the base of the machine, at both sides in front, are synchronized sprockets and film guides. On the right side is a mechanical counter with brass handle. Film may be fed across the front of the machine. A bank of transparent rectangles fits in front of the film, just below the front plate.
label: Description
content: Gibson (1915-2007) carried out studies using the Gibson graph comparator as a graduate student in anthropology at the University of Chicago following World War II. He obtained his PhD. from Chicago in 1952. From 1958 to 1983 he was curator of African ethnology in the Department of Anthropology at the Smithsonian's Museum of Natural history.
label: Description
content: See other materials in accession 1987.0694.
label: Location
content: Currently not on view
topic: label: Subject
content: Mathematics
setName: label: See more items in
content: Medicine and Science: Mathematics
creditLine: label: Credit Line
content: Gift of Gordon D. Gibson
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: 1987.0694.01
label: accession number
content: 1987.0694
label: catalog number
content: 333878
objectType: label: Object Name
content: Comparator
physicalDescription: label: Physical Description
content: aluminum (overall material)
label: Physical Description
content: wood (overall material)
label: Measurements
content: overall: 27 cm x 104 cm x 53.5 cm; 10 5/8 in x 40 15/16 in x 21 1/16 in