Protractors - Surveying
Since the first protractors appeared near the turn of the 17th century, around the same time that the technique of triangulation was developed for surveying, their utility for this activity appeared evident from early on. Surveyors typically carried at least one protractor in their field kits. The instrument might be combined with another drawing instrument, such as a set of parallel rules. By the 19th century, makers tried to blend convenience with multi-functionality, offering rectangular protractors that fit easily in a case or pocket and that were packed with aids for reducing real-world distances to proportional scales. They also showed off their improving craftsmanship with fine objects that retained accuracy in measurement. (See also the page on Engineering & Drafting.)
"Protractors - Surveying" showing 5 items.
Protractor and Parallel Rule
- Description
- This brass parallel rule has a semicircular protractor attached to the top blade. The protractor is divided to degrees and marked by tens from 10 to 90 to 10. A movable arm attached to the origin point of the protractor contains a vernier, which was intended to permit the measurement of angles to 5 minutes of accuracy. The hinges connecting the blades of the rule are straight. There is no maker’s mark.
- Mathematician James McKenna gave this measuring instrument to the Smithsonian. He reported that an ancestor used it at Bedford, Pa., before 1800. A name, scratched on one of the tools in the set of drawing instruments (MA*310891) that accompanied this protractor, suggests that the ancestor was John A. Stuart, a "surveyor in Bedford County whose name is still associated with a line he laid out on Wills Mountain in that area." (p. 90)
- Compare this instrument to 1978.2110.06.
- Reference: Peggy A. Kidwell, "American Parallel Rules: Invention on the Fringes of Industry," Rittenhouse 10, no. 39 (1996): 90–96.
- Location
- Currently not on view
- date made
- late 18th century
- ID Number
- MA*310890
- catalog number
- 310890
- accession number
- 131549
- Data Source
- National Museum of American History, Kenneth E. Behring Center
Rectangular Protractor Sold by McAllister & Co.
- Description
- This ivory rectangular protractor is three times larger in area than many surviving ivory rectangular protractors from the nineteenth century, which tend to be short and narrow enough to fit in a pocket. (See MA*335349, MA*321754, and MA*321014.) Catalogs of the time period advertise foot-long rectangular protractors comparable to this one, but at approximately $12 each, they were 3 to 8 times as expensive as 6-inch versions. Thus, surveyors probably did not purchase and use the large protractors as often.
- This protractor is graduated to half-degrees and marked by tens from 10 to 170 in both the clockwise and counterclockwise directions. The interior of the protractor contains a maker's mark: LONDON MADE. FOR MCALLISTER & CO. PHILADELPHIA. The front of the protractor also contains a diagonal scale; a scale of chords which is divided by half-degrees and marked by tens from 10 to 90; and scales for dividing 1 inch into 10, 20, and 30 parts. These scales were used to create drawings in which 1 inch represented 1, 2, and 3 feet, respectively.
- A chain scale is on the bottom edge of the protractor, facing outwards (i.e., appearing upside-down as one looks at the front of the protractor). The scale is graduated to half-units and marked by ones from 1 to 44 and from 44 to 1. The numbers from 44 to 1 are called an "offset." Ten units on the scale total 1/4" in length. A surveyor's chain was 66 feet long and contained 100 links. Thus, this chain scale represented 4 links to each inch. The number 40 (described as a "line of 40" or a "scale of 40" in trade catalogs) is marked at the midpoint of the protractor, in between the chain scale and the scale dividing 1 inch into 30 parts. The markings are worn off the protractor in a few places.
- The back of the protractor bears scales for dividing the inch into 80, 60, 55, 50, 45, 40, 35, and 30 parts. There are also scales for 1/8, 1/4, 3/8, 1/2, 5/8, 3/4, 7/8, and 1 inch to the foot. The protractor is stored in a black and red leather and cardboard case that is badly worn.
- William Young McAllister (1812–1896) was a third-generation optician and dealer of mathematical instruments in Philadelphia. His firm was known as McAllister & Co. between 1836 and 1853. From 1830 to 1836, he partnered with his father, John McAllister Jr., and between 1853 and 1865 he partnered with his brother, Thomas, who subsequently worked as an optician in New York City. This protractor is slightly different from the 12-inch ivory protractor described in McAllister's 1867 catalog: this object is 1/4" wider; there are eleven scales of equal parts instead of ten; there are eight scales of feet and inches instead of twelve; there is one scale of chords instead of two; and there is a chain scale. John C. Armstrong of Washington, D.C., donated the protractor to the Smithsonian in 1933.
- References: William Ford Stanley, Mathematical Drawing and Measuring Instruments 6th ed. (London: E. & F. N. Spon, 1888), 227–230; Catalogue of Keuffel & Esser, 33rd ed. (New York, 1909), 176; "McAllister Family Business Timeline," The John A. McAllister Collection, Library Company of Philadelphia, http://www.librarycompany.org/mcallister/pdf/McAllister%20family%20business%20timeline.pdf; A Priced and Illustrated Catalogue of Mathematical Instruments . . . Sold Wholesale and Retail by William Y. McAllister (Philadelphia, 1867), 25.
- Location
- Currently not on view
- date made
- 1836-1853
- maker
- McAllister, William Young
- ID Number
- MA*310743
- accession number
- 127352
- catalog number
- 310743
- Data Source
- National Museum of American History, Kenneth E. Behring Center
Protractor Retailed by Benjamin Pike & Son
- Description
- This brass circular protractor was manufactured in the mid-19th century and made available for sale by the New York City firm headed by Benjamin Pike (1777–1863). Pike, a dealer of optical, mathematical, and philosophical instruments whose firm serviced the entire United States, partnered at various times with his sons, Benjamin Jr., Daniel, and Gardner. The business was called “Benjamin Pike & Son,” as is marked on the vernier limb of this protractor, between 1831 and 1841 and between 1843 and 1850.
- This protractor likely would have been of interest to surveyors and engineers. The object is divided by single degrees. It bears two sets of markings by tens in the clockwise direction: from 0° to 90° to 0° to 90° to 0°, and from 10° to 360°. Brass arms extend into the center to divide the protractor into quadrants. The arms are not placed at the 0° and 90° points, as one might expect, but rather at the 50/50, 40/140, 50/230, and 40/320 markings. There are rounded, beveled notches at the 90/90 and 90/270 markings. A round hole (5/8" diameter) is at the center. Crosshairs would typically have been placed in this hole to mark the origin point for measuring angles, but no crosshairs are present. Instead, a brass piece fills about one-third of the hole.
- An arm pivoted from the center carries a vernier, which allows the user to read off angles to 10 minutes of arc. The vernier is marked by 30s from 60 to 0 to 60. The vernier arm is marked: Benj-n Pike & Son New York. The arm extends beyond the vernier. A brass strip, fastened on top of the arm, contains a sharp metal pin that pokes through a hole near the end of the arm. The pin was used to prick, or mark, angle points.
- This protractor has some notable differences from the circular protractor depicted in Pike catalogs of 1848 and 1856: its outer edge is smooth instead of appearing to bear gear teeth; it has one vernier arm instead of two; and it has two sets of markings instead of one.
- References: Deborah J. Warner, “Browse by Maker: Pike,” National Museum of American History Physical Sciences Collection: Surveying and Geodesy, http://americanhistory.si.edu/collections/surveying/maker.cfm?makerid=22; Benjamin Pike Jr., Pike’s Illustrated Descriptive Catalogue of Optical, Mathematical, and Philosophical Instruments (New York, 1848), 43–45; Benjamin Pike Jr., Pike’s Illustrated Descriptive Catalogue of Optical, Mathematical, and Philosophical Instruments (New York, 1856), 43–45; facsimile with historical introduction by Deborah J. Warner (Dracut, Mass., and San Francisco, 1984).
- Location
- Currently not on view
- date made
- 1831-1850
- maker
- Pike, Jr., Benjamin
- ID Number
- MA*304826.059
- accession number
- 1973.304826
- catalog number
- 304826.059
- Data Source
- National Museum of American History, Kenneth E. Behring Center
Protractor and Ruler Scale
- Description
- 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.
- Location
- Currently not on view
- date made
- 1879-1907
- maker
- W. & L. E. Gurley
- Gurley, Lewis E.
- Gurley, William
- ID Number
- MA*247967
- accession number
- 47736
- catalog number
- 247967
- Data Source
- National Museum of American History, Kenneth E. Behring Center
Protractor and Ruler Scale
- Description
- According to the accession record, this "special protractor and scale" is attributed to the factory operated by William and Lewis Ephraim Gurley in Troy, N.Y. No examples of this protractor could be identified in Gurley catalogs, although the "special" may refer to a special order placed by the U.S. Geological Survey, which in 1907 declared this instrument "obsolete" and transferred it to the Smithsonian.
- This semicircular steel protractor within a rectangular frame is exactly like ID number MA*247967, except that there is no second scale to replace the sliding scale screwed to the top of the protractor. The number 1 is marked on the bottom of each of these two screws. This instrument also retains the bottom half of its original mahogany case, which is lined with blue velvet and bears two brass hooks for latching the case. The protractor is disassembled from the straight edge on which it slides so that both pieces fit in the case.
- Reference: Deborah J. Warner, "Browse by Maker: Gurley," National Museum of American History Physical Sciences Collection: Surveying and Geodesy, http://americanhistory.si.edu/collections/surveying/maker.cfm?makerid=14.
- Location
- Currently not on view
- date made
- 1879-1907
- maker
- W. & L. E. Gurley
- Gurley, Lewis E.
- Gurley, William
- ID Number
- MA*247968
- accession number
- 47736
- catalog number
- 247968
- Data Source
- National Museum of American History, Kenneth E. Behring Center