Geometric Model, L. Brill No. 149. Ser. 1 No. 2a, Central Surface of a Paraboloid


This white plaster model has a rectangular base. The surface rising from the base begins as an ellipse and rises to a central peak. No curves are drawn on it.

This model was designed in 1877 by L. Schleiermacher under the supervision of Ludwig Brill at the technical high school in Munich and published as part of the first series issued by Brill. It shows the locus of centers of principal curvature of an elliptic paraboloid (that is to say, the envelope or caustic of reflected rays). The mantels are separated. A tag on the base of the model reads: 149. Another tag reads: Centralfläche des Paraboloids. (/) Verl. v. L. Brill. 1. Ser. Nr. IIa.

See also 1985.0112.0118

This example of the model was exhibited at the German Educational Exhibit at the Columbian Exposition, a World’s Fair held in Chicago in 1893. It there was purchased by Wesleyan University in Connecticut, and subsequently was donated to the Smithsonian.


Ludwig Brill, Catalog mathematischer Modelle. . ., Darmstadt: L. Brill, 1892, p. 3, 86.

Accession file.

Date Made: 1892

Maker: L. Brill

Location: Currently not on view

Place Made: Germany: Hesse, Darmstadt

Subject: Mathematics


See more items in: Medicine and Science: Mathematics, Science & Mathematics


Exhibition Location:

Credit Line: Gift of Wesleyan University

Data Source: National Museum of American History

Id Number: 1985.0112.117Catalog Number: 1985.0112.117Accession Number: 1985.0112

Object Name: geometric modelgeometric model

Physical Description: plaster (overall material)Measurements: overall: 9 cm x 10 cm x 8.5 cm; 3 17/32 in x 3 15/16 in x 3 11/32 in


Record Id: nmah_693993

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