Crozet Protractor Signed by Pike

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This German silver semicircular protractor fits (and slides) within a rectangular brass frame. The protractor is graduated to half-degrees and marked by tens from 0° to 90° to 0° in both the clockwise and counterclockwise directions. The frame is open on the interior except for an extension at the center, to which is screwed a German silver trapezoid with points extending from each side of the base. The trapezoid bears a signature: Crozet's Protractor. B. Pike & Son. N. York. Two sliding thumbscrews in the trapezoid piece permit four different brass scales to be attached. Each scale is rectangular and beveled on the graduated side. The first scale is 10.4 cm long (4-1/4 inches) and is marked from 0 to 13, with each mark divided into 10 parts. The second is the same length and marked in the same way but in the opposite direction (right to left). The third is not numbered; it is 9 cm (3-17/32 inches) long and divided into 17-1/2 sections, each divided into 10 parts. The fourth is 10.4 cm long and marked from 0 to 10.7, with each mark divided into 10 parts.
In 1831, Benjamin Pike (1777–1863) of New York took his eldest son, Benjamin Jr., into his business of retailing optical, mathematical, and philosophical instruments, renaming his firm "Benjamin Pike & Son." Son Daniel joined the firm in 1841, necessitating a change in name to "Benjamin Pike & Sons." The name reverted to the singular "Son" in 1843, when Benjamin Jr. established his own business. In 1850, the youngest son, Gardner, joined Benjamin Pike & Son, and the firm again was known as "Benjamin Pike & Sons." The business was called "Benjamin Pike's Son" from 1867 to 1916. Thus, this protractor was presumably made in the 1830s or 1840s. However, it was not advertised in Pike's 1848 or 1856 catalogs, nor is it listed in later Pike catalogs.
This form of protractor is associated with Claudius Crozet (1789–1864), a French civil engineer who taught at the U.S. Military Academy at West Point, NY, from 1817 to 1823. Crozet served as principal engineer for the state of Virginia until 1832, was a founding faculty member of the Virginia Military Institute between 1837 and 1845, and surveyed roads, railways, and aqueducts throughout his life. The date Crozet devised this instrument is not known. By the late 19th century, it was widely publicized. The entry for "protractor" in Farrow's Military Encyclopedia reads in part: "Crozet's protractor . . . is named from its inventor, an officer of the United States Engineer Corps, and is considered the best among the various protractors yet devised. It may be used with the T-rule or straight edge. The feather edge is always set to the starting point and the line produced without puncturing the paper. The feather edge is the only metallic bearing upon the paper, small ivory projections on the underside of the frame keep the metal from contact with the paper and prevent soiling it." The "Crozet's protractor" illustrating the entry, and other depictions in various trade catalogs, do not have the arm and interchangeable scales on the lower edge of the instrument, however. Instead, they have thumbscrews and a vernier within the T-square frame housing the protractor.
Nonetheless, this instrument is not unique. In 1993, Christie's of London auctioned a Crozet's protractor exactly like this one and bearing the same maker's mark.
This particular instrument is very tarnished. John William Christopher Draper and James Christopher Draper of Pittsburgh donated it to the Smithsonian in 1973.
References: Deborah J. Warner, “Browse by Maker: Pike,” National Museum of American History Physical Sciences Collection: Surveying and Geodesy,; Benjamin Pike Jr., Pike’s Illustrated Descriptive Catalogue of Optical, Mathematical, and Philosophical Instruments, vol. 1 (New York, 1848), 11–13, 28–32, 39–40, 43–45; Illustrated Catalogue of Instruments and Materials for Drawing, Surveying and Civil Engineering. Manufactured, Imported, and For Sale by Benj. Pike's Son & Co. (New York, [ca. 1880]), 30–33; James W. Queen & Co., Catalogue of Mathematical and Engineering Instruments and Materials (Philadelphia, 1887), 56; Edward S. Farrow, comp., Farrow's Military Encyclopedia (New York, 1895), ii:598; W. & L. E. Gurley, A Manual of the Principal Instruments Used in American Engineering and Surveying, 31st ed. (Troy, N.Y., 1895), 321; Catalogue of Keuffel & Esser Co. (New York, 1909), 168; Christie's, "Sale 6105/Lot 138: A lacquered brass Crozet's Protractor,"
Currently not on view
date made
Pike, Jr., Benjamin
place made
United States: New York, New York
Physical Description
metal (overall material)
wood (overall material)
velvet (overall material)
overall: 2.8 cm x 18.3 cm x 12.3 cm; 1 3/32 in x 7 7/32 in x 4 27/32 in
ID Number
accession number
catalog number
Credit Line
Gift of John William Christopher Draper and James Christopher Draper
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Data Source
National Museum of American History


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