Protractors - War
Military operations frequently require surveying and navigational activities. In addition to the tasks described on those pages of this exhibit, early modern military architects used protractors to create designs for fortifications. In the 20th century, protractors were utilized to position artillery pieces. The collections are especially rich in examples from the Felsenthal Instruments Company, a Chicago manufacturer of scientific instruments that was influential from the 1940s to the 1970s.
"Protractors - War" showing 3 items.
Felsenthal A-10 Protractor and Map Coordinator
- Description
- This clear plastic semicircular protractor is divided by ten mils and marked by hundreds from 100 to 3,100 in both the clockwise and counterclockwise directions. It is also divided by single degrees and marked by tens from 0° to 180° in both directions. Diagonal lines extend some of the measurement markings out to the edges of the rectangle surrounding the protractor. Pinholes are at the origin point and in the upper left and right corners. The interior of the protractor has cutout stencils for a circle, triangle, square, and two oblong shapes. The middle also contains scales placed at right angles to each other. They are divided and marked by hundreds from 1,000 to 2[00]. The scales are labeled: 1:21120.
- The left edge of the rectangular plastic piece is divided by tenths of an inch and marked by ones from 1 to 3. Inside the 3-inch ruler is a scale for mils divided by hundreds and marked by thousands from 5,000 to 1,000. The scale continues on the top of the rectangle, again divided by hundreds and marked by thousands from 5,000 to 1,000. The scale is labeled: 1:62500. On the right side of the top is a scale labeled: 1:20,000. It is divided and marked by hundreds from 1,000 to 2[00]. This scale also repeats on the right side of the rectangle. On the right edge of the rectangle, there is a scale divided by millimeters and marked by ones from 1 to 7. It is labeled: METRIC.
- The bottom of the protractor bears a scale divided by hundreds and marked by thousands from 1,000 to 8,000. It is labeled: 1:62500. The bottom edge has a second scale, divided by hundreds and marked by five hundreds from 500 to 3,000. It is labeled: 1:21120. The name of the instrument is printed on the very bottom edge: MAP COORDINATOR AND PROTRACTOR - A-10. Donor Ben Rau dated the object to 1942.
- See also 1977.1141.01, 1977.1141.02, 1977.1141.03, 1977.1141.05, 1977.1141.08, 1977.1141.09, 1977.1141.10, 1977.1141.11, 1977.1141.12, 1977.1141.18, 1977.1141.19, 1977.1141.20, 1977.1141.22, 1977.1141.23, 1977.1141.24, 1977.1141.30, and 1977.1141.39.
- Location
- Currently not on view
- date attributed by donor
- 1942
- maker
- Felsenthal
- ID Number
- 1977.1141.21
- accession number
- 1977.1141
- catalog number
- 336405
- Data Source
- National Museum of American History, Kenneth E. Behring Center
Felsenthal FAE-31Artillery Protractor
- Description
- This semicircular protractor is cut out from the center of a white piece of rectangular plastic. The front is marked in black print. The protractor is divided by half-degrees and marked by tens from 0° to 180° and from 180° to 360°. An arrow points to the index, or origin, point. The bottom edge of the rectangle is divided by two millimeters and marked by single centimeters from 0 to 20. The number 5731 is printed above the left side of the centimeter ruler.
- The upper-left corner is divided by fifties and marked by thousands from 3000 to 1000 to 1000 to 3000. The scale is labeled: YARDS (/) RF = 1:50,000. Between the scale and protractor is printed: USMA (/) MODEL (/) 1953. The upper-right corner is divided by twenties and marked by hundreds from 5 to 1, 1000 to 1[00] to 1000, and 1 to 5. The scale is labeled: YARDS (/) RF = 1:25,000. Between the scale and protractor is printed: PROPERTY OF (/) M. T. AND G. (/) USMA.
- The back of the protractor is marked in red print. The protractor is divided into units of twenty mils and marked by two hundreds from 0 to 3200 and from 3200 to 6400. An arrow points to the index point. The bottom edge of the rectangle is divided by tenths of an inch and marked by ones from 0" to 8".
- The upper-left corner is divided by fifties and marked by thousands from 3,000 to 1,000 to 1,000 to 3,000. The scale is labeled: METERS (/) RF = 1:50,000. Between the scale and protractor is printed: USMA (/) MODEL (/) 1953. The upper-right corner is divided by twenties and marked by hundreds from 5 to 1, 1,000 to 1[00] to 1,000, and 1 to 5. The scale is labeled: METERS (/) RF = 1:25,000. Between the scale and protractor is printed: PROPERTY OF (/) M. T. AND G. (/) USMA.
- Felsenthal Instruments Company manufactured this protractor for the United States Military Academy at West Point, N.Y. Donor Ben Rau, who worked for Felsenthal, dated the object to 1954.
- See also 1977.1141.01, 1977.1141.02, 1977.1141.03, 1977.1141.05, 1977.1141.08, 1977.1141.09, 1977.1141.10, 1977.1141.11, 1977.1141.12, 1977.1141.18, 1977.1141.19, 1977.1141.20, 1977.1141.21, 1977.1141.22, 1977.1141.23, 1977.1141.24, and 1977.1141.39.
- Location
- Currently not on view
- date attributed by donor
- 1954
- maker
- Felsenthal
- ID Number
- 1977.1141.30
- accession number
- 1977.1141
- catalog number
- 336414
- Data Source
- National Museum of American History, Kenneth E. Behring Center
Felsenthal FAO-44 Artillery Protractor
- Description
- This clear plastic semicircular protractor is divided by twenties and marked by two hundreds from 0 to 3,200 and from 3,200 to 6,400. A pinhole is at the origin point. The interior is labeled: ANGULAR MILS; 8016738. This protractor was item no. FAO-44. Felsenthal Instruments Company manufactured it for the U.S. Army about 1958.
- The Felsenthal Instruments Company was the leading supplier of mathematical instruments to the U.S. Army Air Force and the U.S. Navy Bureau of Aeronautics, particularly during World War II (when the firm was known as G. Felsenthal & Sons). After the company ceased operations in approximately 1976, it provided a large sample of its products to the Smithsonian.
- See also 1977.1141.01, 1977.1141.02, 1977.1141.03, 1977.1141.05, 1977.1141.08, 1977.1141.09, 1977.1141.11, 1977.1141.12, 1977.1141.18, 1977.1141.19, 1977.1141.20, 1977.1141.21, 1977.1141.22, 1977.1141.23, 1977.1141.24, 1977.1141.30, and 1977.1141.39.
- Location
- Currently not on view
- date made
- ca 1958
- maker
- Felsenthal
- ID Number
- 1977.1141.10
- accession number
- 1977.1141
- catalog number
- 336394
- Data Source
- National Museum of American History, Kenneth E. Behring Center