Protractor, Stolp's Circular Dividing Instrument

Protractor, Stolp's Circular Dividing Instrument

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This German silver instrument is in a cruciform wooden case lined with velvet. According to the patentee, Myron G. Stolp of Aurora, Illinois, it is an "instrument for dividing a circle into any required number of parts, however minute, and which is, at the same time, adapted for the dividing arrangement of a gear-cutter or dividing engine, and which is also adapted for ascertaining the radius for gear-wheels when the number of teeth and the pitch of the teeth are given, and which is also adapted for use as a protractor for laying out an angle, and for similar and kindred purposes."
The mechanism is described in the patent. A piece of red tape attached to the outside of the box, as well as the source of the object, suggest that it was submitted as a patent model.
Myron Greeley Stolp (1848-1906), the inventor of this device, graduated from Cornell University in 1872, a member of the first class of civil engineers there to comple a four-year course. He then returned to his native Aurora, Illinois, to work in the family woolen mills, and held a variety of other engineering positions. Stolp took out several patents.
"Improvement in Circle-Dividing Instruments," U.S. Patent 192,092, June 19, 1877.
"Myron G. Stolp, '72," Transactions of the Association of Civil Engineers of Cornell University, vol. XIV, 1905-1906, pp. lv-lvi.
Currently not on view
Object Name
date made
Stolp, Myron G.
place made
United States: Illinois, Aurora
Physical Description
German silver (instrument material)
wood (case material)
fabric (case lining, holder for tag material)
case: 5 cm x 41.2 cm x 23 cm; 1 31/32 in x 16 7/32 in x 9 1/16 in
ID Number
catalog number
accession number
Ruling and Dividing Engines
See more items in
Medicine and Science: Mathematics
Single Drawing Instruments
Data Source
National Museum of American History
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