Geometric Model, L. Brill No. 28. Ser. 4 No. 4, Hyperbolic Paraboloid (Ruled Surface)

Geometric Model, L. Brill No. 28. Ser. 4 No. 4, Hyperbolic Paraboloid (Ruled Surface)

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This fixed string model shows a ruled surface, that is to say a surface swept out by a moving straight line. The model was published by the firm of Ludwig Brill in Darmstadt beginning in 1879. This example was exhibited at the German Educational Exhibit at the Columbian Exposition held in Chicago in 1893, where it was purchased by Wesleyan University.
The surface is the saddle-shaped hyperbolic paraboloid, shown in red strings and bounded by a black metal frame. The frame has two straight edges along opposite bottom sides, joined by curved edges to form a four-sided base. Above the two opposite straight base edges are edges in the shape of a parabolas. The parabolas are joined at the top by a cross bar. A row of holes extends along each curved edge at the base and along each parabola.
Ludwig Brill, Catalog mathematischer Modelle..., Darmstadt: L. Brill, 1892, p. 9, 59-60.
Henry Burchard Fine and Henry Dallas Thompson, Coordinate Geometry, New York: Macmillan Company, 1931, pp. 243-244. An example of this model is shown in Figure 7.
Currently not on view
Object Name
geometric model
date made
L. Brill
place made
Germany: Hesse, Darmstadt
Physical Description
string (overall material)
metal (overall material)
overall: 22.5 cm x 17.5 cm x 30 cm; 8 27/32 in x 6 7/8 in x 11 13/16 in
ID Number
catalog number
accession number
Credit Line
Gift of Wesleyan University
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Data Source
National Museum of American History
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