Accession No

1927

Brief Description

slide rule, by Nairne and Blunt, English, 1785 (c)

Origin

England; London

Maker

Nairne and Blunt

Class

calculating

Earliest Date

1785

Latest Date

1785

Inscription Date

Material

wood (boxwood); metal (brass)

Dimensions

length 830mm; breadth 65mm; thickness 20mm

Special Collection

Cavendish collection

Provenance

Transferred from the Cavendish Laboratory, University of Cambridge in 07/1974.

Inscription

‘Nairne
& Blunt’ (cursor)

Description Notes

Boxwood rule, ends of stock bound with brass, brass slow motion screw for fine adjustment of slide, brass cursor engraved with names of scales.
Obverse:
upper part of stock: scales of sine rhumbs marked ‘Sin Rum’ and ‘S.R.’, divided 1 - 8, numbered by 1, 1 - 8 subdivided to 1/8, 7 - 8 subdivided to 0.5. Scale of tangent rumbs, marked ‘Tan Rum’ and ‘T.R.’ divided 17 - 4[0], numbered 17, 26, 35, 4[0]; each section between numbers subdivided to 1/8. Scale of versed sines marked ‘Ver. Sin’ and ‘V Sin’, divided [168˚ 30´] - [0], numbered by 10˚ and for 165˚; 168˚ 30´ - 150˚ subdivided to 10´, 150˚ - 130˚ subdivided to 15´, 130˚ - 100˚ subdivided to 20´, 100˚ - 60˚ subdivided to 30´, 60˚ - 10˚ subdivided to 1˚. Scale of sines marked ‘Sin’, divided [40´] - 90˚, numbered 1, 2, 3...10, 20...90; 40´ - 20˚ subdivided to 10´, 20˚ - 30˚ subdivided to 15´, 30˚ - 50˚ subdivided to 20´, 50˚ - 60˚ subdivided to 30´, 60˚ - 85˚ subdivided to 1˚.
Slide: scale of sines, as on stock. Scale of numbers marked ‘Num’, divided 1 - 10[0], numbered 1, 2, 3...1[0], 12, 15, 2[0], 3[0]...10[0]; 1 - 2 subdivided to 0.01, 2 - 4 subdivided to 0.02, 4 - 7 subdivided to 0.025, 7 - 10 subdivided to 0.05, 10 - 20 subdivided to 0.1, 20 - 40 subdivided to 0.2, 40 - 70 subdivided to 0.25, 70 - 100 subdivided to 0.5. Scale of tangents marked ‘Tan’ divided [40´] - 45˚ and back to [89˚ 20´], numbered 1, 2...10, 20, 30, 40, 45, 50, 55, 60, 70, 80; 40´ - 10˚ subdivided to 10´, 10˚ - 45˚ subdivided to 15´.
Lower part of stock: scales of tangents and numbers as on slide. Scale of meridian degrees, marked ‘D Mer’ divided [0] - 50, numbered by 1, subdivided to 0.1. Second scale of meridian degrees marked ‘Mer Con’ and ‘M D’, divided 50 - [75], numbered by 1, subdivided to 0.1. Scale of degrees of longitude marked ‘D L’, divided [0] - 58˚, numbered by 1˚, subdivided to 0.1.

Reverse: scale of inches divided [0] - [30], numbered by 1, subdivided to 0.1. Scale of ‘Sea Feet’ divided 0 - 2ft 1inch, numbered by 1 inch. Scales of equal parts of an inch, marked for 10, 12 1/2, 15, 20, 25, 30, 35, 40, 45 and 50. Scale of hours marked ‘Hou’ divided [0] - VI, numbered by I, subdivided to 10 minutes. Scale of latitudes marked ‘Lat’ divided [0] - [90˚], numbered by 10˚, 0 - 70˚ subdivided to 1˚, 70˚ - 80˚ subdivided to 2˚. Scale of inclined meridian, marked ‘In Mer’, divided [0] - 90˚, numbered by 10˚, subdivided to 1˚. Two scales of rumbs marked ‘Rum’, divided [0] - 8, numbered by 1, subdivided to 0.25. Scale of meridian longitude, marked ‘M= Lon’, divided 60˚ - [0], numbered by 10˚, subdivided to 1˚. Three scaes of chords, marked ‘Cho’, divided [0] - 90˚, numbered by 10˚, subdivided to 1˚. Scale of Sines marked ‘Sin’, divided [0] - [90˚], numbered by 10˚ to 70˚; 0 - 70˚ subdivided to 1˚, 70˚ - 80˚ subdivided to 2˚, 80˚ - 90˚ subdivided to 5˚. Scale of secants marked ‘Sec’, divided 10 - [80˚ 50´], numbered by 10 and for 75˚; 10˚ - 20˚ subdivided to 2˚, 20˚ - 50˚ subdivided to 1˚, 50˚ - 60˚ subdivided to 30´, 60˚ - 80˚ subdivided to 15´, remainder subdivided to 10´. Scale of tangents, marked ‘Tan’, divided [0] - [81˚], numbered 10, 20, 30, 40, 50, 60, 65, 70, 75, 80; 0 - 40˚ subdivided to 1˚, 40˚ - 60˚ subdivided to 30´, 60˚ - 80˚ subdivided to 15´, remainder subdivided to 10´. Scale of semitangents marked ‘S Tan’ uses same divisions as scale of tangents, but all numbers are doubled.

Condition good; complete.

References

Events