Geometric Model by Eberbach, Cylinder Transformable Into Hyperboloid of One Sheet
date: label: date made
content: ca 1900
name: label: maker
content: Eberbach
notes: label: Description
content: 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.
label: Description
content: A metal tag on the base of the model reads: EBERBACH (/) MAKER (/) ANN ARBOR, MICH
label: Description
content: The model came to the Smithsonian from the Department of Mathematics at the University of Michigan.
label: Description
content: 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
label: Description
content: For another string model by Eberbach, see 1985.0795.31.
label: Description
content: References:
label: Description
content: “A Maker of Scientific Instruments . . .,” <I>Bulletin of Pharmacy</I>, February 1921, vol. 35 #2, p. 75. This is an obituary of Ottmar Eberbach.
label: Description
content: Lela Duff, “Ann Arbor Yesterdays,” <I>Ann Arbor News</I>, June 12, 1961.
label: Description
content: U.S. Census data, Michigan death records, Ann Arbor city directories from ancestry.com.
label: Location
content: Currently not on view
place: label: place made
content: United States: Michigan, Ann Arbor
topic: label: Subject
content: Mathematics
setName: label: See more items in
content: Medicine and Science: Mathematics
label: See more items in
content: Science & Mathematics
creditLine: label: Credit Line
content: Gift of the Department of Mathematics, The University of Michigan
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: 1982.0795.28
label: catalog number
content: 1982.0795.28
label: accession number
content: 1982.0795
objectType: label: Object Name
content: Geometric Model
physicalDescription: label: Physical Description
content: string (overall material)
label: Physical Description
content: brass (overall material)
label: Measurements
content: 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