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Early 17th Century English Sector
[Text discription below]
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40012
An Early 17th Century English Sector:
English ca. 1635. This 20 inch Gunther’s Sector is constructed entirely of pinned, laminated brass, is 6 mm thick, and signed on the hinge “John Allen Fecit.” Length closed is 27.5 cm; Length opened is 50.7 cm. Weight is 584.2 g. The sector has a hinged, fold out triangulation bridge which is revealed when the sector is opened. John "1" Allen (w 1630-1642) was a mathematical instrument maker working near the Savoy in the Strand, London. John "1" Allen started his apprenticeship with his father Elias Allen on June 25, 1617 (3). He was made free of the Grocers’ Company on January 11, 1632, and took Walter Hayes as an apprentice on February 22, 1632. According to the Webster Database at the Adler Planetarium (4), he is recorded to have sold Sectors, Equinoctial meridian sundials, Astrolabes, Quadrants, etc. However, a review of major museum and private collections reveals that surviving instruments by him are not only rare, they are in fact, exceedingly rare. A Gunther’s Sector signed by John Allen is in the Science Museum, London (5) (Object 1986-262). An almost identical sector, although unsigned and attributed to either Elias or John Allen, is in the museum of the History of Science in Oxford (MHS Inventory #14776) (1). The Webster Database also indicates an astrolabe quadrant and a double horizontal sundial by him in the Musees Royaux in Brussels, Belgium (BMR). (The museum has yet to confirm the existence of these instruments.) A ring dial on a stand (ROM-674) and an equinoctial meridian sundial (ROM-7768) are at the Monte Mario Observatory in Rome, Italy.
This sector includes scales of metals, indicated by the appropriate planetary signs (Fig. 1), as well as the usual scales of meridional parts and trigonometrical functions. The scales of metals were used for finding proportional weights of metals and for transforming the data of a given substance into those of another material or size. “Meridional parts” is the length of the arc of a meridian between the equator and a given parallel on a mercator chart. Expressed on the sector in units of 1 arc minute of longitude at the equator (2).
English ca. 1635. This 20 inch Gunther’s Sector is constructed entirely of pinned, laminated brass, is 6 mm thick, and signed on the hinge “John Allen Fecit.” Length closed is 27.5 cm; Length opened is 50.7 cm. Weight is 584.2 g. The sector has a hinged, fold out triangulation bridge which is revealed when the sector is opened. John "1" Allen (w 1630-1642) was a mathematical instrument maker working near the Savoy in the Strand, London. John "1" Allen started his apprenticeship with his father Elias Allen on June 25, 1617 (3). He was made free of the Grocers’ Company on January 11, 1632, and took Walter Hayes as an apprentice on February 22, 1632. According to the Webster Database at the Adler Planetarium (4), he is recorded to have sold Sectors, Equinoctial meridian sundials, Astrolabes, Quadrants, etc. However, a review of major museum and private collections reveals that surviving instruments by him are not only rare, they are in fact, exceedingly rare. A Gunther’s Sector signed by John Allen is in the Science Museum, London (5) (Object 1986-262). An almost identical sector, although unsigned and attributed to either Elias or John Allen, is in the museum of the History of Science in Oxford (MHS Inventory #14776) (1). The Webster Database also indicates an astrolabe quadrant and a double horizontal sundial by him in the Musees Royaux in Brussels, Belgium (BMR). (The museum has yet to confirm the existence of these instruments.) A ring dial on a stand (ROM-674) and an equinoctial meridian sundial (ROM-7768) are at the Monte Mario Observatory in Rome, Italy.
This sector includes scales of metals, indicated by the appropriate planetary signs (Fig. 1), as well as the usual scales of meridional parts and trigonometrical functions. The scales of metals were used for finding proportional weights of metals and for transforming the data of a given substance into those of another material or size. “Meridional parts” is the length of the arc of a meridian between the equator and a given parallel on a mercator chart. Expressed on the sector in units of 1 arc minute of longitude at the equator (2).
Fig. 1: Sector's symbol identification chart.
Condition:
Very fine with brass patination consistent with its age. Built of exceptional quality. One to last for the ages. The three-leaf hinge with a well set linch-pin. All engraving is crisp and with excellent definition. A remarkable surviving instrument from the early 17th century, in a fine state of preservation.
Bibliography:
1. Museum of the History of Science: [www.mhs.ox.ac.uk/collections].
2. History of Computing: [www.nzeldes.com/HOC/Gunter.htm].
3. Clifton, Gloria (1995) Directory of British Scientific Instrument Makers 1550-1851, IBSN [0 302 00634 6] p. 6.
4. Adler Planetarium’s Webster Database (p. 9; OCT 7, 2012; Chicago, IL). Please see: [http://historydb.adlerplanetarium.org/signatures/a.pl].
5. The Science Museum London [www.nmsi.ac.uk] lists a sector signed by John "1" Allen (Cf. Object No. 1986-262) with the dimensions: 4.5 X 247 X 59 mm.
Fig 1. A rare engraving of Elias Allen ca. 1653, by Wenceslaus Hollar.
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