Accession No

1021

Brief Description

gunter sector, by Henry Sutton, English, 1660

Origin

England; London

Maker

Sutton, Henry

Class

calculating; mathematics

Earliest Date

1660

Latest Date

1660

Inscription Date

1660

Material

metal; brass

Dimensions

length 240mm; breadth 40mm

Special Collection

Provenance

On loan from Trinity College, University of Cambridge from 1951.

Inscription

(1) ‘H: Sutton fecit. 1660.’ (obverse)
(2)’Trin: Coll: Cant: Ex Dono Tho Scattergood Arm’ (reverse)

Description Notes

Two arms held by flat circular hinge with crossing strut at non-hinge end; all with scales. [Crossing strut appears to be a later replacement, as it is not engraved in the style of Henry Sutton.]

Obverse: both arms carry scales for sines and tangents.
Sine scale marked ‘S’, divided [0] - 90˚, numbered by 10˚.
Tangent scale in two parts, both marked ‘T’, first part divided [0] - 45˚, numbered by 10˚; second part divided 45˚ - ‘63-26’, numbered by 5˚.
Running along the outer edges are two scales which are continuous when the sector is opened out fully. These are a scale of log sines, marked ‘S’, divided [0] - 90˚, [0] - 60˚, numbered 1, 2, 3…10, 20…90, 20, 30, 40, 50, 60; a scale of log versed sines, marked ‘VS’, divided [0] - 90˚, numbered by 10˚. A further set of three scales also - first is possibly for solar altitude as it is marked with a solar symbol, divided [0] - 90˚, numbered by 10˚; scale of chords, marked ‘C’, divided [0] - 90˚, numbered by 10˚; scale marked ‘ST’, divided [0] - 90˚, numbered by 10˚.
Reverse: both arms carry scales for chords, secants and equal parts. Chord scale marked ‘C’, divided [0] - 60˚, numbered by 10˚. Secant scale marked ‘S’, divided [5]˚ - 60˚, numbered by 10˚. Line of lines or of equal parts, marked ‘L’, divided [0] - 10, numbered by 1.
Running along the outer edges are scales which are continuous when the sector is opened out fully. On the very edge is a scale of log numbers, marked ‘N’, divided [1] - 20[0], numbered 2, 3, 4…9, 1[0], 2[0]…9[0], 10[0], 20[0]. Within this a scale of latitudes, marked ‘L’, divided [0] - 90˚, numbered by 10˚; an unidentified scale, marked ‘I’, divided 0 - [1] - 0; a scale of hours, marked ‘H’, divided 0 - 6, numbered by 1. The innermost scales are another scale of latitudes, marked ‘L’, divided and numbered as before; and a scale of hours, marked ‘H’, divided and numbered as before.
On the outer rims of the arms, forming a continuous scale when sector is fully open is a scale of log tangents, marked ‘T’, divided [0] - 70˚, numbered 1, 2,…9, 10, 20…70. A scale of log cotangents is also included on here, unnamed, divided 20˚ - 80˚, numbered by 10˚. Also an unidentified scale, divided [0] - 50˚, numbered by 10˚ (perhaps a scale of lesser tangents for use in dialling in conjunction with the strut).
On the inner rims of one arm is a scale of inches, unnamed, divided [0] - [9] and back to [18], numbered by 1.
Strut obverse:
dialling scales - latitude scale, solar declination scale and date scale. Latitude scale divided 90˚ - 0 - 90˚, numbered by 10˚. Declination scale divided [23˚ 30´] - 0 - [23˚ 30´], numbered by 10˚. Date scale in two parts, divided solstice to solstice, marked by initials for months (IFMAMIIASOND). Equinoxes at 9.25 March, 12.25 September.
Strut reverse: scales of equal parts, divided in one direction [0] - 8 and in the other direction by [0] - 18, both numbered by 1. Transversal scales at each end for division to 10ths, numbered 2, 4, 6, 8.

good condition

References

Mikey McGovern; 'The Sector'; Explore Whipple Collections online article; Whipple Museum of the History of Science; University of Cambridge: https://www.whipplemuseum.cam.ac.uk/explore-whipple-collections/calculating-devices/sector

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