Accession No

6115

Brief Description

brass gunter sector, by Henry Sutton, English, 1652

Origin

England; London

Maker

Sutton, Henry

Class

calculating; mathematics

Earliest Date

1652

Latest Date

1652

Inscription Date

1652

Material

metal (brass)

Dimensions

length 240mm; breadth 46mm

Special Collection

Provenance

Purchased from Trevor Philip & Sons Ltd., 75a Jermyn St, on or before 20/4/2007.

Inscription

‘H:Sutton fecit. 1653.’ (obverse)

Description Notes

Brass gunter sector by Henry Sutton; English, 1652.

Two arms held by flat circular hinge with crossing strut at non-hinge end; all with scales.

Obverse: both arms carry scales for tangents, a line of lines; 3 logarithmic scales run across the two arms. Tangent scale in two parts, both marked ‘T’, first part divided [0] - 45˚, numbered by 10˚; second part divided 45˚ - 75˚, numbered by 5˚. Line of lines marked ‘L’, divided [0] - 10, numbered by 1. First logarithmic scale unmarked, divided 5, 6, 7, 8, 9, 1 - 10, numbered by 1. Second logarithmic scale unmarked, divided, 3 - 70, numbered 3, 4 ... 10, 20 ... 70. Third logarithmic scale unmarked, divided [0] - 45, and back on itself, 45 - [90], numbered, 2, 3 ... 10, 20 ... 40, 45, the numbered upside down, 50, 60 ... 80, 85, 88.
Reverse: both arms carry scales for sines, ‘S’ and chords; 4 unmarked scales run across the two arms. Sines scale marked ‘S’, divided [0] - 90, numbered by 10. Scale marked ‘S’, divided [0] - 90, numbered by 10. Chords marked ‘C’, divided [0] - 90, numbered by 10. First unmarked scale divided [0] - [90], numbered 0 - 70 by 10 then 75 - 90 by 5. Second unmarked scale divided [0]-200, numbered by 10. Third unmakred scale divided [0] - 180, numbered by 10 [omitting 170]. Fourth unmarked scale divided and numbered with the signs of the zodiac.
Outer edge or arm with blade: unmarked scale of inches divided [0] -9, numbered by 1, unmarked scale divided [0] -7, numbered by 1.
Outer edge of arm without blade: unmared scale, divided [0] - 70, numbered by 10.

good condition

References

Events

Description
Sector
Sectors were used for calculation by navigators, surveyors, gunners and draftsmen (and, famously, by Galileo) from the about the mid 16th century to the mid 19th century. During the 16th century, they were used as general mathematical tools, but the introduction of logarithms drastically expanded their application. Usually made of brass, wood or ivory, they look like a jointed rule with scales engraved on either side.

Sectors use the principle of similar triangles (that the ratio of lengths of two sides of similar triangles will always be the same) with scales of proportion for calculating mathematical functions such as finding the line of equal parts, inscribing a rectangular polygon inside a circle of a given radius and protracting angles. This made them useful for similar calculations to a slide rule.

This gunter sector was made by Henry Sutton, a highly talented and well-known craftsman of his time. He was a prolific manufacturer, making, in particular, paper sundials, which were cheap and also very popular.
18/10/2002
Created by: Saffron Clackson on 18/10/2002

FM:46584