Protractor and Ruler Scale
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- W. & L. E. Gurley
- Gurley, Lewis E.
- Gurley, William
- This steel semicircular protractor is divided by half-degrees and is marked by tens from 360 to 180 and from 180 to 0, both in the counterclockwise direction. A 3/8" line is engraved at the origin point. On its left side, the protractor slides along a steel bar or straight edge. Two thumbscrews at the top of the protractor hold in place a removable scale, which is divided into units of four and marked by 40s from 0 to 720. Forty units correspond to approximately one centimeter. The bottom of each screw is marked "2." The scale moves approximately 60 units to the left or right by turning a third screw against a serrated edge on the scale.
- An additional scale accompanies the object. This scale is divided by fifties and marked by thousands from 0 to 12,000. Ten units correspond to approximately 1.5 centimeters. The protractor was originally stored in a mahogany case, apparently discarded by 1959. The protractor was purchased by the U.S. Geological Survey between 1879 and 1907.
- See also ID number MA.247968.
- Currently not on view
- Credit Line
- Transfer from U.S. Geological Survey
- ID Number
- accession number
- catalog number
- Object Name
- Physical Description
- steel plate (overall material)
- copper (overall material)
- overall: 2 cm x 23 cm x 30.5 cm; 25/32 in x 9 1/16 in x 12 in
- place made
- United States: New York, Troy
- See more items in
- Medicine and Science: Mathematics
- Science & Mathematics
- National Museum of American History
- Record ID
- Metadata Usage (text)
- GUID (Link to Original Record)
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