Geometric Model by Eberbach, Cylinder Transformable Into Hyperboloid of One Sheet

Geometric Model by Eberbach, Cylinder Transformable Into Hyperboloid of One Sheet

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Description
In the late nineteenth century, a few Americans began to make geometric models like those previously imported from Europe. This string model, made by the firm of Eberbach in Ann Arbor, Michigan, is somewhat similar to ones made in France and in Germany at about the same time. The model is adjustable. Two metal rings painted black are mounted vertically, facing one another. A circle of holes lies around the center of each ring – the holes are joined by red threads that form straight lines. If the rings are aligned, the red threads represent a cylinder. If one is rotated, the surface becomes a hyperboloid of one sheet.
A metal tag on the base of the model reads: EBERBACH (/) MAKER (/) ANN ARBOR, MICH
The model came to the Smithsonian from the Department of Mathematics at the University of Michigan.
Christian Eberbach (1817-1921) and his son Ottmar Eberbach (1845-1921) both trained in Germany as pharmacists and worked as druggists in Ann Arbor, Michigan. The 1892 Ann Arbor city directory described them as “druggists and manufacturing chemists, dealers in chemical and physical apparatus.” Surviving catalogs of the successor firm of Eberbach Corporation indeed focus on chemical and physical apparatus, not mathematical models. However, the Eberbachs had close ties to the University of Michigan, so it seems likely that they supplied this instrument
For another string model by Eberbach, see 1985.0795.31.
References:
“A Maker of Scientific Instruments...,” Bulletin of Pharmacy, February 1921, vol. 35 #2, p. 75. This is an obituary of Ottmar Eberbach.
Lela Duff, “Ann Arbor Yesterdays,” Ann Arbor News, June 12, 1961.
U.S. Census data, Michigan death records, Ann Arbor city directories from ancestry.com.
Location
Currently not on view
Object Name
Geometric Model
date made
ca 1900
maker
Eberbach
place made
United States: Michigan, Ann Arbor
Physical Description
string (overall material)
brass (overall material)
Measurements
overall: 35.8 cm x 30.7 cm x 21.8 cm; 14 3/32 in x 12 3/32 in x 8 19/32 in
ID Number
1982.0795.28
catalog number
1982.0795.28
accession number
1982.0795
Credit Line
Gift of the Department of Mathematics, The University of Michigan
subject
Mathematics
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Data Source
National Museum of American History
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