Hart Combination Protractor, Rule, and Square

This paper semicircular protractor is divided by degrees and marked by tens from 10 to 170 degrees in both directions. The letter A is printed in the bottom left corner of the protractor, and B is printed in the bottom right corner of the protractor. Centered under the origin point of the protractor is printed the inventor's mark: Combination Protractor, Rule, and Square (/) W. W. Hart, University of Wisconsin.
A ruler along the top edge is divided to 1/8-inch and marked by ones from 0 to 5. A ruler along the bottom edge is divided to millimeter and marked by ones from 0 to 12. The typeface of the inventor's mark is similar to that shown in Hart's textbooks published in the 1920s, such as Walter Wilson Hart, Junior High School Mathematics, vol. 1 (Boston: D. C. Heath & Co., 1921), vii, 131. See also MA*304722.06.
Currently not on view
Object Name
date made
ca 1925
Hart, Walter Wilson
Physical Description
paper (overall material)
overall: .1 cm x 13.5 cm x 8.2 cm; 1/32 in x 5 5/16 in x 3 7/32 in
place made
United States: Wisconsin, Madison
ID Number
accession number
catalog number
Science & Mathematics
Education, High School
See more items in
Medicine and Science: Mathematics
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
Gift of Brown University Department of Mathematics

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