Model of a Cylindroid by Richard P. Baker, Baker #83 (a Ruled Surface)

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This string model was constructed by Richard P. Baker, possibly before 1905 when he joined the mathematics faculty at the University of Iowa. Baker believed that models were essential for the teaching of many parts of mathematics and physics, and over one hundred of his models are in the museum collections. Baker mentioned the model in a 1905 listing of one hundred models he had constructed as well as in a 1931 catalog.
A typed paper label on the top of the wooden base of this model reads: No. 83 (/) CYLINDROID.
Like several other models Baker made, this shows a ruled surface, also called a scroll. Such a surface is swept out by a moving line. This line is represented by the blue string in the model. The string rotates periodically about the vertical access, and at the same time moves uniformly up (or down) the vertical axis. The surface also is known as Plücker’s conoid after the German mathematician and physicist Julius Plücker.
R. P. Baker, A List of Mathematical Models, [1905], p. 13.
R. P. Baker, Mathematical Models, Iowa City, Iowa, 1931, p. 72.
Currently not on view
date made
ca 1900-1935
Baker, Richard P.
place made
United States
Physical Description
thread (overall material)
wood (overall material)
metal (overall material)
blue (overall color)
black (overall color)
screwed and threaded (overall production method/technique)
average spatial: 19.7 cm x 17.3 cm x 16.9 cm; 7 3/4 in x 6 13/16 in x 6 21/32 in
ID Number
accession number
catalog number
Credit Line
Gift of Frances E. Baker
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Data Source
National Museum of American History


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