Brass quadrant by Peter and John Dollond, 18 inch radius with optical sights on tripod

Made:
1780-1820 in London
maker:
Peter and John Dollond, Peter & John
Portable brass quadrant of 18-inch radius with optical sights Portable brass quadrant of 18-inch radius with optical sights Portable brass quadrant of 18-inch radius with optical sights Portable brass quadrant of 18-inch radius with optical sights Portable brass quadrant of 18-inch radius with optical sights Portable brass quadrant of 18-inch radius with optical sights Portable brass quadrant of 18-inch radius with optical sights Portable brass quadrant of 18-inch radius with optical sights

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Portable brass quadrant of 18-inch radius with optical sights
Science Museum Group Collection
© The Board of Trustees of the Science Museum, London

Portable brass quadrant of 18-inch radius with optical sights
Science Museum Group Collection
© The Board of Trustees of the Science Museum, London

Portable brass quadrant of 18-inch radius with optical sights
Science Museum Group Collection
© The Board of Trustees of the Science Museum, London

Portable brass quadrant of 18-inch radius with optical sights
Science Museum Group Collection
© The Board of Trustees of the Science Museum, London

Portable brass quadrant of 18-inch radius with optical sights
Science Museum Group Collection
© The Board of Trustees of the Science Museum, London

Portable brass quadrant of 18-inch radius with optical sights
Science Museum Group Collection
© The Board of Trustees of the Science Museum, London

Portable brass quadrant of 18-inch radius with optical sights
Science Museum Group Collection
© The Board of Trustees of the Science Museum, London

Portable brass quadrant of 18-inch radius with optical sights
Science Museum Group Collection
© The Board of Trustees of the Science Museum, London

Brass quadrant of 18-inch radius with optical sights on a tripod stand. Made by Peter and John Dollond, St Paul’s churchyard, London, and issued by the British Admiralty for surveying work in Lower Canada.

This London-made quadrant was supplied by the British Admiralty around 1800 for surveys in Lower Canada, present-day Quebec. It is associated with Lt.-Colonel Joseph Bouchette (1774-1841), the Surveyor-General of Lower Canada.

Quadrants are used to measure the altitude of celestial objects and the angular distance between them. They were used by surveyors to determine precisely their longitude and latitude.

Much of the territory in Lower Canada was relatively unknown to the British. They produced maps, charts and topographical sketches of the region as they sought to defend their interests against indigenous peoples, and against the French and Americans.

Details

Category:
Astronomy
Object Number:
1911-214
Materials:
brass and glass
Measurements:
overall: 990 mm x 810 mm x 515 mm, 32 kg
type:
quadrant - optical
credit:
British Admiralty (Hydrographic Department)

Parts

Spirit level from brass quadrant

Spirit level from brass quadrant

Object Number:
1911-214/3
type:
spirit levels
Base (foot) from brass quadrant

Base (foot) from brass quadrant

Object Number:
1911-214/4
type:
quadrants
Base (foot) from brass quadrant

Base (foot) from brass quadrant

Object Number:
1911-214/5
type:
quadrants
Base (foot) from brass quadrant

Base (foot) from brass quadrant

Object Number:
1911-214/6
type:
quadrants
Glass beaker from brass quadrant

Glass beaker from brass quadrant

Object Number:
1911-214/7
type:
quadrants
Brass weight from brass quadrant

Brass weight from brass quadrant

Object Number:
1911-214/8
type:
quadrants