Accession No

1031

Brief Description

Quadrant for surveying, c. 1700-1750

Origin

England

Maker

Class

surveying

Earliest Date

1700

Latest Date

1750

Inscription Date

Material

metal (brass)

Dimensions

radius 117mm; thickness 14mm

Special Collection

Provenance

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

Inscription

Description Notes

Brass. Limb graduated 0-90˚ clockwise and anti-clockwise to 15’. Slit sights mounted on reverse at both ends of both straight edges. Compass set into quadrant. 16 point brass rose graduated 0-90-0˚ twice by 10 and 0-90-0˚ twice in single degrees on upper scale. Blued needle. Point for suspension of plumb bob. (Missing).

References

Events

Description
Quadrant
A quadrant is a quarter of a circle, and there are different types of instrument that come under that description. The size of quadrants varied hugely from Tycho Brahe’s highly successful huge 2m radius one, to the more portable versions of the 18th century. In all examples it was important to keep movement, wear and flexure to a minimum, especially if results were to form part of an extended research program and to be compared with one another.

The quadrant was the principle measuring instrument of astronomy in the 17th and 18th centuries, being used in all major observatories. Plain sights (where the angle was simply read off by eye) were replaced by telescopic sights in more sophisticated examples.

18/10/2002
Created by: Saffron Clackson on 18/10/2002

FM:43348