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 18 items.
Page 2 of 2
Felsenthal FAE-23A Artillery Protractor
- Description
- This clear plastic semicircular protractor is divided by tens and marked by hundreds from 100 to 3,100 mils and from 3,300 to 6,300 mils. Mils are units used in artillery and other military applications; 1,000 mils is equivalent to 56.25°. A pinhole is at the origin point. The bottom edge of the protractor is divided by hundreds and marked by thousands from 3,000 to 0. A vernier appears to the right of the scale. The scale is labeled: 1/25,000 METERS. Superimposed on the scale is a second scale, divided by two hundreds and marked (in red) by two thousands from 0 to 6,000. A vernier appears to the left of that scale, which is labeled (in red): 1/50,000 METERS.
- The interior of the protractor has a relatively small semicircular opening with a groove parallel to the origin point. Below the opening is a maker's mark: 8 INCH (/) FELSENTHAL INSTRUMENTS CO. (/) CHICAGO (/) FAE-23A. The letters U.S. are printed above the origin point. Donor Ben Rau, who worked for Felsenthal, dated the object to 1951. The form of the signature indicates the protractor was probably manufactured for the U.S. Army in the 1960s.
- This protractor is very similar to 1977.1141.11. See also 1977.1141.01, 1977.1141.02, 1977.1141.03, 1977.1141.05, 1977.1141.08, 1977.1141.09, 1977.1141.10, 1977.1141.18, 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.
- Reference: Copyright Office, Library of Congress, "Books and Pamphlets," Catalog of Copyright Entries, 3rd ser., 16, part 1, no. 2 (1964): 1392.
- Location
- Currently not on view
- date attributed by donor
- 1951
- date made
- 1960s
- maker
- Felsenthal Instrument Co.
- ID Number
- 1977.1141.12
- accession number
- 1977.1141
- catalog number
- 336396
- Data Source
- National Museum of American History, Kenneth E. Behring Center
Felsenthal FAE-22A Artillery Protractor
- Description
- This clear plastic semicircular protractor is divided by tens and marked by hundreds from 100 to 3,100 mils and from 3,300 to 6,300 mils. Mils are units used in artillery and other military applications; 1,000 mils is equivalent to 56.25°. A pinhole is at the origin point. The bottom edge of the protractor is divided by hundreds and marked by thousands of meters from 6,000 to 0. A vernier appears to the right of the scale. The scale is labeled: 1/25,000. Superimposed on the scale is a second scale, divided by two hundreds and marked (in red) by two thousands from 0 to 12,000. A vernier appears to the left of that scale, which is labeled (in red): 1/50,000.
- The interior of the protractor has a semicircular opening with a groove parallel to the origin point. Below the opening is a maker's mark: FSN 6675-556-0118 (/) PROTRACTOR, 16 INCH (/) FELSENTHAL INSTRUMENTS CO. (/) CHICAGO (/) FAE-22A. The letters U.S. are printed above the origin point. Donor Ben Rau, who worked for Felsenthal, dated the object to 1950, but the form of the signature indicates the protractor was probably manufactured for the U.S. Army in the 1960s.
- This protractor is very similar to 1977.1141.12. 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, 1977.1141.18, 1977.1141.19, 1977.1141.21, 1977.1141.22, 1977.1141.23, 1977.1141.24, 1977.1141.30, and 1977.1141.39.
- Reference: Copyright Office, Library of Congress, "Books and Pamphlets," Catalog of Copyright Entries, 3rd ser., 16, part 1, no. 2 (1964): 1392.
- Location
- Currently not on view
- date attributed by donor
- 1950
- date made
- 1960s
- maker
- Felsenthal Instrument Co.
- ID Number
- 1977.1141.20
- accession number
- 1977.1141
- catalog number
- 336404
- Data Source
- National Museum of American History, Kenneth E. Behring Center
Felsenthal FAE-21Artillery Protractor
- Description
- This clear plastic semicircular protractor is divided by tens and marked by hundreds from 100 to 3,100 mils and from 3,300 to 6,300 mils. Mils are units used in artillery and other military applications; 1,000 mils is equivalent to 56.25°. A pinhole is at the origin point. The bottom edge of the protractor is divided by hundreds and marked by five hundreds from 0 to 7,000. A small vernier appears to the left of the scale, and the scale is labeled: 1/25,000 METERS.
- The interior of the protractor has a semicircular opening with a groove parallel to the origin point. Below the opening is a maker's mark: 12 INCH (/) G. FELSENTHAL & SONS, INC. (/) FAE-21. Donor Ben Rau dated the object to 1945, but the form of the signature indicates the protractor was probably manufactured for the U.S. Army in the 1950s.
- This protractor is very similar to 1977.1141.11. See also 1977.1141.01, 1977.1141.02, 1977.1141.03, 1977.1141.05, 1977.1141.08, 1977.1141.09, 1977.1141.10, 1977.1141.12, 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 attributed by donor
- 1945
- date made
- 1960s
- maker
- G. Felsenthal & Sons, Inc.
- ID Number
- 1977.1141.22
- accession number
- 1977.1141
- catalog number
- 336406
- Data Source
- National Museum of American History, Kenneth E. Behring Center
Felsenthal FAE-21A Artillery Protractor
- Description
- This clear plastic semicircular protractor is divided by tens and marked by hundreds from 100 to 3,100 mils and from 3,300 to 6,300 mils. Mils are units used in artillery and other military applications; 1,000 mils is equivalent to 56.25°. A pinhole is at the origin point. A second hole with diameter 3mm appears just above the origin point. The bottom edge of the protractor is divided by hundreds and marked by thousands from 5,000 to 0. A vernier appears to the right of the scale. The scale is labeled: 1/25,000 METERS. Superimposed on the scale is a second scale, divided by two hundreds and marked (in red) by two thousands from 0 to 10,000. A vernier appears to the left of that scale, which is labeled (in red): 1/50,000 METERS. The red markings are significantly faded.
- The interior of the protractor has a relatively small semicircular opening with a groove parallel to the origin point. Below the opening is a maker's mark: 12 INCH (/) FELSENTHAL INSTRUMENTS CO. (/) CHICAGO (/) FAE-21A. The letters U.S. are printed above the origin point. Donor Ben Rau dated the object to 1950, but the form of the signature indicates the protractor was probably manufactured for the U.S. Army in the 1960s.
- This protractor is very similar to 1977.1141.12. 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, 1977.1141.18, 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.
- Reference: Copyright Office, Library of Congress, "Books and Pamphlets," Catalog of Copyright Entries, 3rd ser., 16, part 1, no. 2 (1964): 1392.
- Location
- Currently not on view
- date attributed by donor
- 1950
- date made
- 1960s
- maker
- Felsenthal Instrument Co.
- ID Number
- 1977.1141.23
- accession number
- 1977.1141
- catalog number
- 336407
- Data Source
- National Museum of American History, Kenneth E. Behring Center
Felsenthal Range Deflection Protractor
- Description
- This clear plastic sixth-circle protractor is graduated into 10 groups of 20 divisions, each labeled with the number 50. The unit of angular measure is mils, which was utilized in artillery applications. There are 6,400 mils in a circle (i.e., 1 mil = 0.05625 degrees). The arc on this instrument is 1,000 mils, or 56.25 degrees, in length.
- An arm extends from the left side of the protractor. The arm is divided to half-units and marked by five (scaled) meters from 160 to 10. Two holes with diameters of 5mm are next to the 145–140 and 30–25 marks. The vertex of the protractor bears a small notch.
- The interior of the protractor is marked: PROTRACTOR, RANGE DEFLECTION (/) SCALE 1:25,000 (/) RANGE 16,000 (/) METERS. Stamped inside a box is the text: THIS TRAINING AID WILL BE RETURNED (/) TO THE FIELD ARTILLERY SCHOOL (/) UPON COMPLETION OF THE SUB-COURSE (/) WITH WHICH ISSUED. Donor Ben Rau dated the instrument to 1965.
- See also 1977.1141.01, 1977.1141.02, 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, 1977.1141.30, and 1977.1141.39.
- Location
- Currently not on view
- date made
- 1965
- maker
- Felsenthal Instrument Co.
- ID Number
- 1977.1141.03
- accession number
- 1977.1141
- catalog number
- 336387
- Data Source
- National Museum of American History, Kenneth E. Behring Center
Felsenthal FAE-28 Artillery Protractor
- Description
- This clear plastic circular protractor is divided by tenths and marked by ones from 1 to 63. In the 48-64 quadrant, it is also marked in red print by ones from 32 to 17. The scale is labeled: AZIMUTH-MILS (100). The interior of the 16–32 quadrant is cut out. Each of the straight sides bears a scale divided by fifties and marked by thousands from 0 to 4,000. The scales are labeled: METERS RF 1: 50,000.
- An arm extending from the 0-16 quadrant is divided by tenths and marked by ones from 1 to 17. The scale is labeled: RANGE METERS (1000). The interior of the 32–48 quadrant bears a maker's mark: FELSENTHAL INSTRUMENTS CO. (/) MFR'S CODE 22040 (/) MFR'S PART NO. FAE-28. The protractor was used to predict the direction and distance of artillery rounds. Donor Ben Rau wrote "Massengale" (which may refer to a particular U.S. Army officer) on the tag he provided with this instrument, and he dated the object to 1966.
- See also 1977.1141.01, 1977.1141.02, 1977.1141.03, 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, 1977.1141.30, and 1977.1141.39.
- Location
- Currently not on view
- date attributed by donor
- 1966
- maker
- Felsenthal Instrument Co.
- ID Number
- 1977.1141.05
- accession number
- 1977.1141
- catalog number
- 336389
- Data Source
- National Museum of American History, Kenneth E. Behring Center
Felsenthal FAE-19A Artillery Protractor
- Description
- While many protractors simply measure angles in degrees, others have been adapted for more specialized contexts. For instance, they may be combined with other drawing instruments, such as rulers or templates for flow chart components. Or, they may make measurements in other scales for angles, such as radians. Before computerized and satellite navigation equipment was in wide use, protractors were employed in military applications, including positioning artillery.
- Thus, this clear plastic protractor, which is in the shape of a sixth-circle, permitted the user to plot the distance traveled by a projectile from the time that elapsed before the sound of the projectile was heard. The outer edge of the protractor's arc is divided by hundredths and marked by tenths from +3.4 to +0.1 (in black print) and from -0.1 to -3.4 (in red print). The scale is labeled: TIME INTERVAL, SECONDS and MIDPOINTS FOR 4-SECOND SUB-BASE, 1/25000.
- A scale marked DEGREES is further inside the arc. It is divided by minutes and marked by fives from 55° to 0°. Finally, a scale for MILS is divided by tens and marked by hundreds from 1000 to 100. 1000 mils is equivalent to 56.25°. A scale for THOUSANDS OF YARDS 1/25000 is along the right edge of the protractor. It is divided by five-hundredths and marked by ones from 14 to 1.
- The maker's mark is near the vertex: 4 SOUND SECONDS (/) FELSENTHAL INSTRUMENTS CO. (/) MFR'S PART NO. FAE-19A (/) MFR'S CODE 22040.
- 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 1977.1141.02, 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, 1977.1141.30, and 1977.1141.39.
- Reference: Deborah J. Warner, “Browse by Maker: Felsenthal,” National Museum of American History Physical Sciences Collection: Navigation, http://americanhistory.si.edu/collections/navigation/maker.cfm?makerid=173.
- Location
- Currently not on view
- date attributed by donor
- 1950
- date made
- 1970s
- maker
- Felsenthal Instrument Co.
- ID Number
- 1977.1141.01
- accession number
- 1977.1141
- catalog number
- 336385
- Data Source
- National Museum of American History, Kenneth E. Behring Center
Felsenthal FAE-19B Artillery Protractor
- Description
- This clear plastic sixth-circle protractor is divided along its outer edge by hundredths and marked by tenths from +1.7 to +0.1 (in black print) and from -0.1 to -3.4 (in red print). The scale is labeled: TIME INTERVAL, SECONDS. The left edge of the protractor is divided by tens and marked by hundreds from 2000 to 600. The scale is labeled: LENGTH OF SUB-BASE, YARDS. The right edge of the protractor is divided by halves and marked by ones from 14 to 1. The scale is labeled: THOUSANDS OF YARDS (/) 1/25000.
- The interior of the protractor is filled with diagonal lines. Three scales are among the diagonal lines, each numbered by tenths in black and in red print. The outermost is numbered from 3.9 to 0.1; the middle scale is numbered from 3.0 to 0.1; and the innermost is numbered from 2.2 to 0.1.
- The maker's mark is near the vertex, which is notched: 2 SOUND SECONDS (/) TEMPLATE, 1/25000 (/) FELSENTHAL INSTRUMENTS CO. (/) MFR'S PART NO. FAE-19B (/) MFR'S CODE 22040. There is a large plus sign to the right of the maker's mark.
- The Chicago firm that manufactured this protractor was known as Felsenthal Instruments Co. in the 1960s and 1970s. Ben Wharton Rau (1904–1995) and his wife, Margery Felsenthal Rau (1916–2010), arranged the donation of this object and many other instruments to the Smithsonian. Margery's father, Irving (1887–1956), was one of the "Sons" of G. Felsenthal & Sons, as the company was known in the 1940s and 1950s. Margery's grandfather, Gabe Felsenthal, founded the firm in 1899.
- Ben Rau worked for the Felsenthals. His duties included touring military facilities with a large display of the company's products. He catalogued hundreds of instruments when the company went out of business in 1976. He dated this protractor and 1977.1141.01 to 1950. While the form was indeed probably older, the maker's name on the instrument indicates it was manufactured in the 1960s or 1970s. Rau also held patents on a collapsible film reel, a proportional divider, and a belt buckle assembly.
- See also 1977.1141.01, 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, 1977.1141.30, and 1977.1141.39.
- References: Deborah J. Warner, “Browse by Maker: Felsenthal,” National Museum of American History Physical Sciences Collection: Navigation, http://americanhistory.si.edu/collections/navigation/maker.cfm?makerid=173; "Irving G. Felsenthal," Chicago Tribune, February 26, 1956, http://www.susaneking.com/genealogy/showsource.php?sourceID=S01752&tree=GreenebaumSam; Copyright Office, Library of Congress, "Books and Pamphlets," Catalog of Copyright Entries, 3rd ser., 16, part 1, no. 2 (1964): 1392; Ben W. Rau, "Collapsible Film Reel" (U.S. Patent 3,447,759 issued June 3, 1969), "Proportional Divider" (U.S. Patent D214,399 issued June 10, 1969), "Belt Buckle Assembly" (U.S. Patent 3,475,797 issued November 4, 1969).
- Location
- Currently not on view
- date attributed by donor
- 1950
- date made
- 1970s
- maker
- Felsenthal Instrument Co.
- ID Number
- 1977.1141.02
- accession number
- 1977.1141
- catalog number
- 336386
- Data Source
- National Museum of American History, Kenneth E. Behring Center