Accession No

0689

Brief Description

sinical quadrant, 1675

Origin

Maker

Class

drawing

Earliest Date

1675

Latest Date

1675

Inscription Date

1675

Material

ivory

Dimensions

radius 96 mm

Special Collection

Robert Whipple collection

Provenance

Purchased by F.C. Dannot, Paris, France, from a collection of M. Dubreuil on 05/01/1933.

Inscription

‘1675 H.A.S.V.W.’

Description Notes

Ivory. Limb graduated [0] - 12, numbered by 1; subdivided to sixteenths from [0] - 5 and to eighths from 5 - 12 (sixteenths still marked with a dot; 18-1-2000). Index arm graduated [0] - 8, numbered to 1, subdivided to 1/4. Index arm with clip underneath. Straight edges graduated [0] - 8, numbered to 1, subdivided to 4 (subdivided to 1/4; 18-1-2000) with rectilinear network extended across quadrant.
Reverse: arc graduated 90˚ - 32˚, numbered by 10, subdivided to 1˚. Also some lines and letters marked, one labelled ‘Geodisie 1/4 de cercle’.

Condition: good.

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:42749