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

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

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Science Museum Group Collection
© The Board of Trustees of the Science Museum, London

Science Museum Group Collection
© The Board of Trustees of the Science Museum, London

Science Museum Group Collection
© The Board of Trustees of the Science Museum, London

Science Museum Group Collection
© The Board of Trustees of the Science Museum, London

Science Museum Group Collection
© The Board of Trustees of the Science Museum, London

Science Museum Group Collection
© The Board of Trustees of the Science Museum, London

Science Museum Group Collection
© The Board of Trustees of the Science Museum, London

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

Brass quadrant by Peter and John Dollond of 18-inch radius with optical sights on a tripod

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.

More

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.

Materials:
glass and brass (copper, zinc alloy)
Object Number:
1911-214/1
type:
optical quadrant - measuring device
Image ©
The Board of Trustees of the Science Museum, London
Components for Dollond portable quadrant

Components for Dollond portable quadrant

Components for Dollond portable quadrant

Object Number:
1911-214/2
type:
optical quadrant - measuring device
Image ©
The Board of Trustees of the Science Museum
Spirit level from brass quadrant

Spirit level from brass quadrant

Spirit level from portable brass quadrant of 18-inch radius with optical sights on a tripod stand by Dollond, London.

Object Number:
1911-214/3
type:
spirit levels
Image ©
The Board of Trustees of the Science Museum
Base (foot) from brass quadrant

Base (foot) from brass quadrant

Circular brass foot from portable brass quadrant of 18-inch radius with optical sights on a tripod stand by Dollond, London, larger side of foot is smooth and flat, tapers to a smaller diameter with concentric circle indentations

Object Number:
1911-214/4
type:
quadrants
Image ©
The Board of Trustees of the Science Museum
Base (foot) from brass quadrant

Base (foot) from brass quadrant

Circular brass foot from portable brass quadrant of 18-inch radius with optical sights on a tripod stand by Dollond, London, larger side of foot is smooth and flat, tapers to a smaller diameter with concentric circle indentations

Object Number:
1911-214/5
type:
quadrants
Image ©
The Board of Trustees of the Science Museum
Base (foot) from brass quadrant

Base (foot) from brass quadrant

Circular brass foot from portable brass quadrant of 18-inch radius with optical sights on a tripod stand by Dollond, London, larger side of foot is smooth and flat, tapers to a smaller diameter with concentric circle indentations

Object Number:
1911-214/6
type:
quadrants
Image ©
The Board of Trustees of the Science Museum
Glass beaker from brass quadrant

Glass beaker from brass quadrant

Glass beaker from portable brass quadrant of 18-inch radius with optical sights on a tripod stand by Dollond, London, slightly flared out from base with small brass hook

Object Number:
1911-214/7
type:
quadrants
Image ©
The Board of Trustees of the Science Museum
Brass weight from brass quadrant

Brass weight from brass quadrant

Brass weight from portable brass quadrant of 18-inch radius with optical sights on a tripod stand by Dollond, London, short brass cylinder with six holes in a parallel line from top to bottom, with small hook to attach

Object Number:
1911-214/8
type:
quadrants
Image ©
The Board of Trustees of the Science Museum