This ivory instrument has two rectangular arms with flat edges and is held together by a circular brass hinge. The scales run from top to bottom on each arm, unlike the paired double scales on Italian and French sectors. On one side, each arm has a sine scale, running from 10 to 80 degrees; a tangent scale, running from 45 to 75 degrees; and a second tangent scale, running from 10 to 45 degrees. Spanning both arms on the outer edge are three scales: log tangent, running from 2 to 40 degrees; log sine, running from 1 to 70 degrees; and logarithmic, running from 2 to 10 and then from 1 to 10. A double line separates these scales from the inner, diagonal set of scales. The top face of the instrument has a scale of equal parts that runs from 90 to 10. There is no maker's mark.
The other side has a double scale along the fold line for regular polygons, labeled POL and running from 12 to 4 sides. Each arm has a scale of equal parts, running from 1 to 10 and labeled L; a secant scale, running from 20 to 75 and labeled S; and a scale of chords, running from 10 to 60 and labeled C. The scales for dialing typically found on English-style sectors are not present. Spanning both arms on the outer edge is a scale of inches, running from 11 to 1 and divided to tenths of an inch. The sector likely dates to the mid-19th century. Compare to MA.335351, MA.333937, and MA.321755.
The donor kept this object and 1985.0580.01 in a blue cardboard box that originally held 12 Eldorado 4H no. 2 pencils made by the Joseph Dixon Crucible Company of Jersey City, N.J. Dixon sold this brand from 1917 to the mid-1950s.
Reference: Dennis B. Smith, "Wood Cased Drafting Pencils," Leadholder: The Drafting Pencil Museum, http://leadholder.com/wood-dixon-eldorado.html.
This ivory instrument has two rectangular arms with flat edges and is held together by a circular brass hinge. The scales run from top to bottom on each arm. On one side, each arm has a sine scale, running from 10 to 80 degrees; a tangent scale, running from 50 to 75 degrees; and a second tangent scale, running from 10 to 45 degrees. Spanning both arms on the outer edge are three scales: log tangent, running from 2 to 45 degrees; log sine, running from 1 to 70 degrees; and logarithmic, running from 1 to 10 twice. The top face of the instrument has a scale of equal parts that divides one foot into 100 increments and runs from 90 to 10. There is no maker's mark.
The other side has a double scale along the fold line for regular polygons, labeled POL and running from 12 to 4 sides. Each arm has a scale of equal parts, running from 1 to 10 and labeled L; a secant scale, running from 40 to 75 and labeled s; and a scale of chords, running from 10 to 60 and labeled C. The scales for dialing typical of 18th-century English-style sectors are not present. Spanning both arms on the outer edge is a scale of inches, running from 12 to 1 and divided to tenths of an inch. The sector likely dates to the mid-19th century. Compare to 1985.0580.06, MA.335351, and MA.321755.
This brass instrument has two hinged arms, each with three curves at the end. Six double scales (i.e., the scales on one arm are identical to those on the other arm) are on one side. The outermost runs from 1 to 12 and is labeled "Forti" on one arm. The second scale is labeled "Lin : Metali :" on the other arm and marked with the letters: I, T, C, S, L, Q, G. These correspond to the specific weights of different metals. The third scale runs from 30 to 3 and is labeled "Div Cir" on the first arm. The fourth scale runs from 10 to 180 and is not labeled. The fifth scale runs from 5 to 100. The sixth scale is located where the two arms meet and is marked with engravings of various polyhedra. Two short single scales are on the lower arm near the hinge; one is marked L and the other is marked I.
The reverse side also has six double scales. The outermost is marked with polyhedra. The second runs from 3 to 30 and is labeled sub poli on one arm. The third is a scale of equal parts that runs from 10 to 200. The fourth runs from 15 to 3 and is labeled Tetrag : on one arm. This is a scale of tetragonic lines, for squaring regular areas and the circle. The fifth runs from 10 to 100 and is labeled Qua on one arm. The innermost scale is marked 1/6 of the distance from the hinge with a 6, 1/5 of the way with a 5, and so on to halfway down the instrument with a 2. The scale is labeled "Divid :" on the lower arm.
Galileo outlined this arrangement of scales in 1606, which is why this example is considered to be in the Italian style. The previous owner believed it was made in the 18th century. The inside edge of one arm is marked with the letters I S, but nothing else is known about the maker.
Reference: Galileo Galilei, Operations of the Geometric and Military Compass, trans. and intro. Stillman Drake (Washington, D.C.: Smithsonian Institution Press, 1978).
The silver hinge is undecorated on this ivory instrument with rectangular arms. On one side and from the top down, each arm has a sine scale, running from 10 to 90 degrees; a tangent scale, running from 45 to 75 degrees; and a second tangent scale, running from 10 to 45 degrees. Spanning both arms on the outer edge are three scales: log tangent, running from 2 to 30 degrees; log sine, running from 1 to 70 degrees; and logarithmic, labeled num and running from 1 to 10 twice and then from 10 to 20. The hinge is marked: Ramsden (/) London.
The other side has a double scale along the fold line for regular polygons, from 12 to 4 sides. Each arm has a scale of equal parts, running from 1 to 10 and labeled L; a secant scale, running from 20 to 75 and labeled s; and a scale of chords, running from 10 to 60 and labeled C. The upper arm has scales labeled IM and Cho that each run from 10 to 90. The lower arm has scales labeled Lat, running from 10 to 70; and Hou, running from I to VI. These four scales are associated with making sundials. Spanning both arms on the outer edge is a scale of inches, running from 11 to 1 and divided to tenths of an inch.
After training under several notable makers of instruments, Ramsden operated his own shop from before 1765 to 1800. His equatorial telescopes and sextants were of especially high quality, and he invented a dividing engine for engraving angular divisions on circular instruments. The second model for his dividing engine is now owned by the Smithsonian, MA.215518.
The object was purchased in 1960.
References: Gloria Clifton, Directory of British Scientific Instrument Makers 1550–1851 (London: National Maritime Museum, 1995), 277; Anita McConnell, Jesse Ramsden (1735–1800): London's Leading Scientific Instrument Maker (Aldershot, England: Ashgate, 2007); Randall C. Brooks, "Dividing Engine," in Instruments of Science: An Historical Encyclopedia, ed. Robert Bud and Deborah Jean Warner (New York and London: Garland Publishing, 1998), 184–186.
The arms of this brass instrument have straight edges, but the hinge is decorated with a flower. One side has double scales of chords, running from 10 to 180; of solids, running from 1 to 64; and for the specific weights of five metals, marked with their symbols. On one arm, the outer edge has a scale that runs from 4 to 24 and is labeled "Poids des Boulets." The sector is marked: Lennel à La (/) Sphére à Paris.
The other side has double scales for equal parts, running from 10 to 200; for architectural drawings, running from 1 to 64; and for the lengths of the sides of inscribed regular polygons, from 12 sides to three sides. On one arm, the outer edge has a scale running from 4 to 24 and labeled "Calibre des Pieces."
In 1774, Louis-Pierre-Florimond Lennel took over the Paris workshop operated by his teacher, Jacques Canivet, who previously had succeeded his uncle, the famous instrument maker Claude Langlois. All three men supplied telescopes to French astronomers. By 1781, Lennel called himself the official maker for France's king and the navy. He died by 1784 and was succeeded by his widow.
References: Maya Hambly, Drawing Instruments, 1580–1980 (London: Sotheby's Publications, 1988), 28; Harriet Wynter and Anthony Turner, Scientific Instruments (New York: Charles Scribner's Sons, 1975), 158; Adler Planetarium, Webster Signature Database, http://historydb.adlerplanetarium.org/signatures/.
The two arms on this brass hinged sector have decorative curves at one end. An acanthus scroll motif is on the hinge. Five double scales (i.e., the scales on one arm are identical to those on the other arm) are on one side. The scales are labeled on both legs. The outermost scale is labeled Metallorum and marked with the letters: Aur, Mer, Plu, Arg, Cup, Fer, Sta, Mar, Sax. These correspond to the specific weights of different metals. The second scale runs from 4 to 40 and is labeled Quadratrix Segmentorum. The third scale is marked with engravings of various polyhedra and the letters: D, I, C, S, O, T. It is labeled Solidorum Regularum. The fourth scale runs from 20 to 3. The letters D and R are on either side of the number 7. The scale is labeled Planorum AEqualium. The innermost scale runs from 10 to 180 and is labeled Graduum Circuli.
The reverse side has four double scales. The outermost runs from 20 to 3 and is labeled Figurarum Regularium. The second runs from 1 to 100 and is labeled Planorum. The third runs from 1 to 125 and is labeled Solidorum. The innermost scale runs from 20 to 300 and is labeled Partium AEqualium. One arm has a scaled diagram, labeled Orthographia Munimentorum, for dividing various heights, lengths, and depths of military fortifications into sections. The other arm has a table labeled Tabula Ignographia Munimentorum that gives the proportional dimensions for areas of fortifications that have between four and ten sides.
The outer edges of the arms have scales that run from 1/4 to 64. One is labeled Poids des boulets, and the other is labeled Calibre des pieces. Although most of the scales on this instrument reflect the Italian style of sector, these scales are typical of sectors made for the French market. See, for example, MA.321676 and MA.333929.
In the closed position, the front of the sector reads: Iacobus Lusuerg (/) Mutinensis Faciebat (/) Roma Ao. 1683. Jacob Lusuerg and his son, Dominicus, made mathematical instruments in Rome and Modena from 1674 until 1719. Henry Russell Wray, the previous owner of this instrument, graduated from the University of Pennsylvania and was a businessman in Colorado Springs, Colo., in the early 20th century.
References: Jim Bennett and Stephen Johnston, The Geometry of War, 1500–1750 (Oxford: Museum of the History of Science, 1996); Maya Hambly, Drawing Instruments, 1580–1980 (London: Sotheby's Publications, 1988), 25.
This ivory instrument has two rectangular arms with flat edges and is held together by a circular brass hinge. The scales run from top to bottom on each arm. On one side, each arm has a sine scale, running from 10 to 90 degrees; a tangent scale, running from 45 to 75 degrees; and a second tangent scale, running from 10 to 45 degrees. Spanning both arms on the outer edge are three scales: log tangent, running from 2 to 45 degrees; log sine, running from 1 to 70 degrees; and logarithmic numbers, running from 1 to 10 twice. The top face of the instrument has a scale of equal parts that divides one foot into 100 increments and runs from 90 to 10. There is no maker's mark.
The other side has a double scale along the fold line for regular polygons, labeled POL and running from 12 to 4 sides. Each arm has a scale of equal parts, running from 1 to 10 and labeled L; a secant scale, running from 40 to 75 and labeled s; and a scale of chords, running from 10 to 60 and labeled C. The scales for dialing typically found on 18th-century English-style sectors are not present. Spanning both arms on the outer edge is a scale of inches, running from 11 to 1 and divided to tenths of an inch. The sector likely dates to the 19th century. Compare to 1985.0580.06, MA.333937, and MA.335351.
Before slide rules were widely used by engineers and draftsmen, instrument makers often included a sector in a set of drawing instruments. Users opened the sector to a desired angle, measured distances between numbers with a pair of dividers, and made calculations according to the principles of similar triangles. The donor reported that her husband's ancestor, Lt. Col. Alexander Matheson (b. 1788), was the original owner of this drawing instrument. He settled in Perth, Canada, after serving in the British military during the War of 1812.
Reference:
Thomas Kentish, A Treatise on a Box of Instruments and the Slide Rule (London: Relfe & Fletcher, 1847), 39–61.
This small brass instrument has two hinged arms, each with a steel point at the end. On one side, both arms have a single scale that runs from 8 (near the hinge) to 1 and is labeled Lin. Recta. If 1 is the full length of the line, 2 represents 1/2 the length, 3 is 1/3 the length, and so on. One arm on this side also has a scale marked with the number 3 at both ends. It is 1/3 the length of the instrument. The single scale on the other side runs from 15 to 6 and is labeled Lin. Circularis. It is used to indicate the length of arcs of a circle. If the points are set at opposite ends of the radius of a circle (the distance marked "6"), a polygon inscribed in the circle with sides equal to that distance will have six sides. A polygon inscribed in the circle at the separation marked "7" will have seven sides, and so on.
Instruments of this type were introduced in Italy, probably by Guidobaldo del Monte, and first described by G. P. Gallucci in a book about mathematical instruments published in Venice in 1598. They were used into the seventeenth century, but they were superseded by more complicated sectors. In particular, Galileo expanded on and publicized the arrangement of scales in 1606, and his form became known as the Italian style.
Reference: Galileo Galilei, Operations of the Geometric and Military Compass, trans. and intro. Stillman Drake (Washington, D.C.: Smithsonian Institution Press, 1978), 12.
The arms of this brass instrument have plain ends, but the hinge is decorated with a flower. One side has a double scale of chords that runs from 10 to 180; a double scale for "les Solides" that runs from 1 to 60; and a double scale for the specific weights of five metals, marked with their symbols. The outer edge of both arms has a scale that runs from 1/4 to 60 and is labeled Diamettre [sic] et Poids des Boulets. The sector is marked: Butterfield (/) AParis.
On the other side, the outer edge has a scale that runs from 1/4 to 60 and is labeled Calibre des Pieces. There are double scales of equal parts, running from 10 to 200; for "les plans," running from 10 to 60; and for inscribed regular polygons, from 12 sides to three sides. Compare to MA.321676 and 1985.0580.04.
Michael Butterfield (1635–1724) was an English instrument maker who worked in France from around 1677 until his death. He was best known for his distinctive sundials.
References: Maya Hambly, Drawing Instruments, 1580–1980 (London: Sotheby's Publications, 1988), 24, 134–135; Anthony Turner, "Sector," in Instruments of Science: An Historical Encyclopedia, ed. Robert Bud and Deborah Jean Warner (New York and London: Garland Publishing, 1998), 526–528.
The arms of this brass instrument have straight edges, but the hinge is decorated with a sunburst. One side has double scales of chords, running from 10 to 180; of architectural drawings, running from 5 to 60; and for the specific weights of four metals, marked with their symbols. The outer edge has a scale that runs from 1/4 to 64 and is labeled Calibres des Pieces. There is no maker's mark.
The other side has double scales for equal parts, running from 0 to 200; for solids, running from 5 to 60; and for the lengths of the sides of inscribed regular polygons, from 12 sides to three sides. The outer edge has a scale running from 1/4 to 64 and labeled Poids des Boulets. The outside face of the instrument has scales for English feet and French feet, each running from 1 to 6. This instrument was found in Smithsonian storage in 1956.
This small, one-sided brass sector has two flat rectangular arms, hinged at one end. A flower decorates the hinge. The instrument has double scales of chords, running from 10 to 90, and of specific weights for five metals, marked with their symbols. The outer edge has a scale that runs from 1/4 to 33 and is labeled Pouts [sic] des boulets. The instrument is marked: N Bion (/) A –Paris. The signature is slightly different from the one on the other sector from Bion's workshop in the collection, 1985.0580.05.
Nicolas Bion (c. 1652–1733) made and sold mathematical instruments in Paris in his own shop and as royal maker for Louis XIV. He included a lengthy discussion of sectorial scales in his famous 1709 manual on the construction and use of mathematical instruments. Bion's son, Jean-Baptiste, took over the shop in 1731.
The Smithsonian acquired this sector in 1962 from Jacob (Jake) Zeitlin and Josephine Ver Brugge Zeitlin, who operated a rare books store for over 40 years in West Hollywood, Calif.
References: Nicolas Bion, Traité de la construction et des principaux usages des instruments de mathematique (Paris, 1709), 29–74; Gloria Clifton, Directory of British Scientific Instrument Makers 1550-1851 (London: National Maritime Museum, 1995), 2–3; Beverly Beyette, "Zeitlin Auction: A Bittersweet Final Chapter," Los Angeles Times, February 4, 1988; Mary Rourke, "Josephine Ver Brugge Zeitlin, 90; Sold Rare Books, Journals," Los Angeles Times, February 26, 2005.
This yellowed ivory instrument has two rectangular arms with flat edges and is held together by a circular brass hinge. The lower arm is broken. The scales run from top to bottom on each arm. On one side, each arm has a sine scale, running from 10 to 80 degrees; a tangent scale, running from 45 to 75 degrees; and a second tangent scale, running from 10 to 45 degrees. Spanning both arms on the outer edge are three scales: log tangent, running from 3 to 45 degrees; log sine, running from 1 to 70 degrees; and logarithmic numbers, running from 1 to 10 twice. A double line separates these scales from the inner, diagonal set of scales. The top face of the instrument has a scale of equal parts that divides one foot into 100 increments and runs from 90 to 10. There is no maker's mark.
The other side has a double scale along the fold line for regular polygons, labeled POL and running from 12 to 4 sides. Each arm has a scale of equal parts, running from 1 to 10 and labeled L; a secant scale, running from 20 to 75 and labeled s; and a scale of chords, running from 10 to 60 and labeled C. The scales for dialing typically found on 18th-century English-style sectors are not present. Spanning both arms on the outer edge is a scale of inches, running from 12 to 1 and divided to tenths of an inch. Compare to MA.321755, MA.333937, and 1985.0580.06.
This sector may have been used at the New York Meteorological Observatory in Central Park, established and directed by Daniel Draper from 1868 to 1911.
References: Christopher J. Sangwin, "Edmund Gunter and the Sector," January 21, 2003, http://web.mat.bham.ac.uk/C.J.Sangwin/Sliderules/sector.pdf; Robert S. Harding and Jeffrey L. Tate, "Draper Family Collection, ca. 1826–1936," Archives Center, National Museum of American History, http://amhistory.si.edu/archives/d8121.htm.
The arms of this brass instrument have straight edges, but the hinge is decorated with a straight and squiggly lines. One side has a double scale of chords that runs from 10 to 130; a double scale for "Les Solides" that runs from 1 to 60; and a double scale for the specific weights of four metals, marked with their symbols. Two holes are drilled on either side of the 80 mark on the scales of chords on the lower arm. The outer edge of the lower arm has a scale that runs from 4 to 24 and is labeled "pd des boulets" (for the weight of iron shot).
On the other side, the outer edge has a scale that runs from 4 to 24 and is labeled "Cbres des Pieces" (for the size of iron shot, given the diameter of the barrel and the weight of the shot). There are double scales of equal parts, running from 10 to 200; for architectural drawings, running from 10 to 60; and for inscribed regular polygons, from 12 sides to three sides. Compare to MA.321676 and 1985.0580.04.
According to the accession file, the donor collected this instrument in Mobile, Ala., around 1898 and sent it to the Smithsonian in 1936.
The arms of this small brass instrument have straight ends. One side has a double scale of chords that runs from 10 to 90. The outer edge on one arm has a scale that runs from 4 to 24 and is labeled poids des boulets. The inner edge of both arms has a double scale for the specific weights of four metals, marked with their symbols. The sector is marked: Butterfield (/) AParis. The hinge is decorated with a flower.
On the other side, the outer edge of one arm has a scale that runs from 4 to 24 and is labeled Calibre des pieces. Both arms have double scales of equal parts, running from 10 to 120, and for inscribed regular polygons, from 12 sides to three sides. Compare to MA.321677 and 1985.0580.04.
Michael Butterfield (1635–1724) was an English instrument maker who worked in France from around 1677 until his death. He was best known for his distinctive sundials.
References: Maya Hambly, Drawing Instruments, 1580–1980 (London: Sotheby's Publications, 1988), 24, 134–135; Adler Planetarium, Webster Signature Database, http://historydb.adlerplanetarium.org/signatures/; Henri Michel, Scientific Instruments in Art and History, trans. R. E. W. Maddison and Francis R. Maddison (Barrie and Rockliff, 1967), 206.
This large brass instrument has two rectangular arms with flat ends and an undecorated hinge. On one side and from the top down, each arm has a sine scale, running from 10 to 90 degrees; a tangent scale, running from 45 to 75 degrees; and a second tangent scale, running from 10 to 45 degrees. The top arm has a scale labeled "Rum." that runs from 1 to 8, and the lower arm has a scale labeled "Lon." that runs from 60 to 10. Spanning both arms on the outer edge are four scales: log tangents, running from 1 to 45 degrees; log sines, running from 1 to 90 degrees; log versed sines, running from 165 to 10 degrees; and logarithmic, labeled "Num." and running from 1 to 10 twice. The front is marked: Thos. Harris & Son (/) British Museum London.
The other side has a double scale along the fold line for regular polygons, from 12 to 4 sides. Each arm has a "line of lines" scale, running from 1 to 10; a secant scale, running from 10 to 75; and a scale of chords, running from 10 to 60. The upper arm has a scale of equal parts, running from 90 to 10, and scales for the inclined meridian, chords, and sines, each running from 10 to 90. The lower arm has scales for tangents, running from 10 to 45; latitude, running from 10 to 90; hours, running from I to VI; and chords, running from 0 to 180. Spanning both arms along the outer edge is a scale of inches, running from 24 to 1 and divided to twentieths of an inch.
The London telescope maker Thomas Harris (about 1750–1827) took his son, William, as a partner in 1806. By 1817, the firm was located on Great Russell Street, across from the entrance to the British Museum, and presented itself as "opticians to the Royal Family." In 1846, the workshop moved to High Holburn Street; it remained in business until the 20th century.
References: Gloria Clifton, Directory of British Scientific Instrument Makers 1550–1851 (London: National Maritime Museum, 1995), 125–126; Adler Planetarium, Webster Signature Database, http://historydb.adlerplanetarium.org/signatures/.
This ivory instrument has two rectangular arms with flat edges and a circular brass hinge. The scales run from top to bottom on each arm, unlike the paired double scales on Italian and French sectors. On one side, each arm has a sine scale, running from 10 to 90 degrees; a tangent scale, running from 45 to 75 degrees; and a second tangent scale, running from 10 to 45 degrees. Spanning both arms on the outer edge are three scales: log sine, running from 2 to 70 degrees; log tangent, running from 1 to 45 degrees; and logarithmic, running from 1 to 10 twice and then from 10 to 20. The top face of the instrument has a scale of equal parts that runs from 100 to 10. The front is marked: *Gilkerson* (/) Tower-Hill-London.
The other side has a double scale along the fold line for regular polygons, labeled POL and running from 12 to 4 sides. Each arm has a scale of equal parts, running from 1 to 10 and labeled L; a secant scale, running from 20 to 75 and labeled s; and a scale of chords, running from 10 to 60 and labeled C. The upper arm has scales labeled Im and Ch that each run from 10 to 90. The lower arm has scales labeled La, running from 10 to 70; and H, running from I to VI. These four scales (inclinations of meridians, chords, latitudes, and hours) are associated with making sundials. Spanning both arms on the outer edge is a scale of inches, running from 11 to 1 and divided to tenths of an inch.
James Gilkerson was in business in Tower Hill, London, from 1809 to 1825. Donor Ada B. Richey reported that her husband's ancestor, Lt. Col. Alexander Matheson (b. 1788), was the original owner of this drawing instrument. He settled in Perth, Canada, after serving in the British army during the War of 1812.
References: Gloria Clifton, Directory of British Scientific Instrument Makers 1550–1851 (London: National Maritime Museum, 1995), 113; J. F. Heather, Mathematical Instruments: Their Construction, Adjustment, Testing, and Use, rev. ed. (London: Crosby Lockwood and Co., 1870), i:42–52; Samuel Sturmy, "The Art of Dialling," The Mariner's Magazine (London, 1669).
This brass instrument has rectangular arms hinged at one end. The hinge is decorated with a flower on both sides. One side has double scales of chords, running from 10 to 140; of solids, running from 10 to 60; and for the specific weights of four metals, marked with their symbols. The outer edge of one arm has a scale that runs from 4 to 24 and is labeled poids des boulets. The sector is marked: Butterfield (/) AParis.
The other side has a double scale of equal parts that runs from 10 to 200; an unlabeled double scale that runs from 10 to 60 and is presumably for making architectural drawings; and a double scale for inscribed regular polygons, from 12 sides to three sides. The outer edge of one arm has a scale for Calibre des pices [sic] that runs from 4 to 24. Compare to MA.321676 and MA.321677.
Michael Butterfield (1635–1724) was an English instrument maker who worked in France from around 1677 until his death. He was best known for his distinctive sundials.
References: Maya Hambly, Drawing Instruments, 1580–1980 (London: Sotheby's Publications, 1988), 24, 134–135; Harriet Wynter and Anthony Turner, Scientific Instruments (New York: Charles Scribner's Sons, 1975), 113.
The arms of this brass instrument have straight edges, while the hinge is decorated with a floral design. The sector is marked: P. Le Maire (/) AParis. One side has double scales of chords, running from 10 to 180; of solids, running from 1 to 60; and for the specific weights of four metals, marked with their symbols. The outer edge has a scale running from 1/4 to 60 and labeled Diamettres [sic] et Poids des Boulets (for the diameter and weight of iron shot).
The other side has double scales for equal parts, running from 10 to 200; for architectural drawings, running from 1 to 60; and for the lengths of the sides of inscribed regular polygons, from 12 sides to four sides. The outer edge has a scale that runs from 1/4 to 60 and is labeled Calibres des Pieces (for the size of iron shot, given the diameter of the barrel and the weight of the shot). This arrangement of scales is standard for sectors manufactured in France.
Pierre Le Maire (1717–1785) took over his father Jacques's workshop in the late 1730s. Large numbers of his sundials, mathematical instruments, and lodestones survive. He and his workers initially signed instruments with "le Fils," so this example was probably made after 1750. The donor received this sector from a distant relative, Gunther Mathies, who emigrated from Germany in the early 20th century and worked for the Thomaston Clock Company in Connecticut.
This brass instrument has rectangular arms hinged at one end. The hinge is decorated with a flower on both sides. One side has double scales of chords, running from 10 to 180; of solids, running from 1 to 64; and for the specific weights of five metals, marked with their symbols. The outer edge has a scale that runs from 1/4 to 64 and is labeled poids des Boulets. The sector is marked: N. Bion (/) AParis.
The other side has double scales for equal parts, running from 10 to 200; for architectural drawings, running from 1 to 64; and for the lengths of the sides of inscribed regular polygons, from 12 sides to three sides. The outer edge has a scale running from 1/4 to 64 and labeled Calibre des pieces.
Nicolas Bion (c. 1652–1733) made and sold mathematical instruments in Paris in his own shop and as royal maker for Louis XIV. He included a lengthy discussion of sectorial scales in his famous 1709 manual on the construction and use of mathematical instruments. Albert Haertlein (1895–1960), who collected this sector, graduated with a bachelor's degree in civil engineering from the Massachusetts Institute of Technology in 1918, served in the engineering corps of the U.S. Army during World War I, and taught engineering at Harvard from 1919 until 1959. He was prominent in the American Society of Civil Engineers.
References: Nicolas Bion, Traité de la construction et des principaux usages des instruments de mathematique (Paris, 1709), 29–74; "News From the Classes," Technology Review 21 (1919): 645; Albert Haertlein, Papers, HUG4444, Harvard University Archives, Cambridge, Mass.
This brass instrument has two arms with flat edges, an undecorated hinge, and a central crossbar attached to the end of one arm that fits into a notch on the other arm to hold the sector open at a fixed acute angle. On one side and from the top down, each arm has a sine scale, running from 10 to 90 degrees; a tangent scale, running from 45 to 75 degrees; and a second tangent scale, running from 10 to 45 degrees. The top arm has a scale labeled "Rum." that runs from 1 to 8, and the lower arm has a scale labeled "Lon." that runs from 60 to 10. Spanning both arms on the outer edge are three scales: log tangents, running from 1 to 45 degrees and labeled "Tan."; log sines, running from 1 to 75 degrees and labeled "Sines"; and logarithmic, running from 1 to 10 twice and labeled "Num." This side is marked: Wm. Harris Holborn (/) London.
The other side has a double scale along the fold line for regular polygons, from about 8 to 4 sides. Each arm has a "line of lines" scale, running from 1 to 10; a secant scale, running from 30 to 75; and a scale of chords, running from 10 to 60. The upper arm has scales for the inclined meridian, chords, and sines, each running from 10 to 90. The lower arm has scales for tangents, running from 10 to 45; latitude, running from 10 to 90; and hours, running from I to VI. Spanning both arms along the outer edge is a scale of equal parts, running from 90 to 10; and a scale of inches, running from 12 to 1 and divided to tenths of an inch. On both sides of the instrument, the scales are small, worn, and difficult to read.
William Harris owned a workshop that made spectacles, telescopes, and mathematical and philosophical instruments on High Holburn Street in London from 1799 to 1839, when the workshop was renamed William Harris & Son.
References: Gloria Clifton, Directory of British Scientific Instrument Makers 1550–1851 (London: National Maritime Museum, 1995), 126; Adler Planetarium, Webster Signature Database, http://historydb.adlerplanetarium.org/signatures/.