Geometric Model, L. Brill No. 12. Ser. 4, No. 2, Cylinder, Cone and Plane Transformable into One-Sheeted Hyperboloid and Hyperbolic Paraboloid

From the early nineteenth century, mathematicians and engineers have studied surfaces generated by motion. The gold threads of this model form a cylinder, the red ones a double cone. Rotating the top circle of the frame twists the gold threads and untwists the red ones, forming surfaces called hyperboloids. The blue threads, which initially lie in a plane, become a hyperbolic paraboloid. This model was made in Germany and exhibited at the Columbian Exposition, the world's fair held in Chicago in 1893. It came to the Smithsonian from the mathematics department of Wesleyan University in Connecticut.
Currently not on view
Object Name
geometric model
Date made
Brill, L.
Physical Description
metal (overall material)
string (overall material)
glass (overall material)
overall: 63.5 cm x 35 cm x 16 cm; 25 in x 13 3/4 in x 6 5/16 in
Place Made
Deutschland: Hessen, Darmstadt
ID Number
accession number
catalog number
Worlds Fair
Science & Mathematics
See more items in
Medicine and Science: Mathematics
Data Source
National Museum of American History, Kenneth E. Behring Center
Adjustable String Model
Credit Line
Gift of Wesleyan University

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