L. Brill No. 159, Ser. 10.1 No. 7, D41,6

L. Brill No. 159, Ser. 10.1 No. 7, D41,6

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The German label on this white plaster model indicates that it is a model of a wave surface for a uniaxial optical crystal, Brill Ser. 6 No. 3. The catalog entry for that Brill number adds (with negative birefringence) at the end of the title. Such a model always has an outer shell that is an ellipsoid and an inner shell that is a sphere. However, this model is a sphere with one octant cut away to reveal part of an ellipsoid. Thus this is a model of a wave surface of a positive uniaxial crystal, whose Brill model number is No. 159, Ser. 10.1 No. 7.
Stand 304722.23.01 may be for this model, as both have tag D41,6.
Compare to 1985.0112.125.
The correct label for this model appears on 1982.0795.23.
This is one of a series of models designed at the Munich polytechnic high school under the direction of Alexander Brill in 1885.
L. Brill, Catalog, 1892, p. 21, 87.
For examples of related models, with a reference to a related publication, see the Goettingen collection of mathematical models, model numbers 283 (Schilling #356) and 284 (Schilling #357).
Francis A. Jenkins and Harvey E. White, Fundamentals of Optics, New York: McGraw Hill, 1976, p. 553-555.
Currently not on view
Object Name
Geometric Model
Other Terms
Geometric Model; Wave Surface
date made
L. Brill
place made
Physical Description
plaster (overall material)
overall: 10 cm x 10 cm x 10 cm; 3 15/16 in x 3 15/16 in x 3 15/16 in
ID Number
catalog number
accession number
Credit Line
Gift of the Department of Mathematics, The University of Michigan
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Data Source
National Museum of American History
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