Geometric Model, L. Brill No. 196. Ser. 16, No. 9, Union of a Confocal Ellipsoid, Hyperboloid of One Sheet, and Hyperboloid of Two Sheets

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In 1888, Ludwig Brill of Darmstadt published a series of nine models for teaching about surfaces of the second degree that have the same foci (confocal surfaces). The plaster models were patterned after some designed by the Finnish mathematician Edvard Rudolf Neovius (1851-1917) of Helsinki. This, the ninth in the series, represents the union of models I, IV and V in the series – that is to say a confocal ellipsoid, hyperboloid of one sheet, and hyperboloid of two sheets. A torn paper tag on the model reads: [. . .] 6. A second torn paper tag reads: [. . .] ids mit [. . .] (/) [. . .] und ein [. . .] (/) [. . .] Hyperbolo [. . .] (/) [. . .] Ser. I. Nr. IX.
This example of the model was exhibited at the Columbian Exposition, a world’s fair held in Chicago in 1893, where it was purchased by Wesleyan University.
Compare 1990.0571.20.
L. Brill, Catalog mathematischer Modelle. . ., Darmstadt: L. Brill,1892, p. 37, 76.
Currently not on view
date made
L. Brill
place made
Deutschland: Hessen, Darmstadt
Physical Description
plaster (overall material)
overall: 21.5 cm x 29.5 cm x 15.5 cm; 8 15/32 in x 11 5/8 in x 6 3/32 in
ID Number
catalog number
accession number
Credit Line
Gift of Wesleyan University
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Data Source
National Museum of American History


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