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This is one of a set of seven models of surfaces representing space curves of fourth order designed by Karl Rohn, professor of mathematics at the technical high school in Dresden. The series was first published by Brill in 1892. The black metal frame of the string model has two round sides and two H-shaped sides. The top and bottom are in the general shape of quadrilaterals. The threads are green and red, with gold beads. At this writing, most threads are broken.
This example of the model was exhibited at the Columbian Exposition, a World’s Fair held in Chicago in 1893.
Compare models 1985.0112.181, 1985.0112.182, 1985.0112.183, 1985.0112.184, and 1985.0112.186.
L. Brill, Catalog mathematischer Modelle..., Darmstadt: L. Brill, 1892, pp. 40-42, 75.
An example of this model is #8 in the Altgeld collection of mathematical models at the University of Illinois. An image of it has a tag with the Brill series 21, number 5 designation. See http://www.mathmodels.illinois.edu/cgi-bin/cview?SITEID=4&ID=372.
Currently not on view
Germany: Hesse, Darmstadt
string (overall material)
glass (overall material)
metal (overall material)
overall: 21.6 cm x 18.7 cm x 20.5 cm; 8 1/2 in x 7 3/8 in x 8 1/16 in